Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Training of primary chicken monocytes results in enhanced pro-inflammatory responses
    Verwoolde, Michel B. ; Biggelaar, Robin H.G.A. van den; Baal, Jürgen van; Jansen, Christine A. ; Lammers, Aart - \ 2020
    Veterinary Sciences 7 (2020)3. - ISSN 2306-7381
    Flow cytometry - Inflammatory response - Innate immune memory - Macrophages - Primary chicken monocytes - Β-glucan

    Beta-glucan-stimulated mammalian myeloid cells, such as macrophages, show an increased responsiveness to secondary stimulation in a nonspecific manner. This phenomenon is known as trained innate immunity and is important to prevent reinfections. Trained innate immunity seems to be an evolutionary conserved phenomenon among plants, invertebrates and mammalian species. Our study aimed to explore the training of primary chicken monocytes. We hypothesized that primary chicken monocytes, similar to their mammalian counterparts, can be trained with β-glucan resulting in increased responses of these cells to a secondary stimulus. Primary blood monocytes of white leghorn chickens were primary stimulated with β-glucan microparticulates (M-βG), lipopolysaccharide (LPS), recombinant chicken interleukin-4 (IL-4) or combinations of these components for 48 h. On day 6, the primary stimulated cells were secondary stimulated with LPS. Nitric oxide (NO) production levels were measured as an indicator of pro-inflammatory activity. In addition, the cells were analyzed by flow cytometry to characterize the population of trained cells and to investigate the expression of surface markers associated with activation. After the secondary LPS stimulation, surface expression of colony stimulating factor 1 receptor (CSF1R) and the activation markers CD40 and major histocompatibility complex class II (MHC-II) was higher on macrophages that were trained with a combination of M-βG and IL-4 compared to unstimulated cells. This increased expression was paralleled by enhanced NO production. In conclusion, this study showed that trained innate immunity can be induced in primary chicken monocytes with β-glucan, which is in line with previous experiments in mammalian species. Innate immune training may have the potential to improve health and vaccination strategies within the poultry sector.

    Innate immune training and metabolic reprogramming in primary monocytes of broiler and laying hens
    Verwoolde, Michel B. ; Biggelaar, Robin H.G.A. van den; Vries Reilingh, Ger de; Arts, Joop A.J. ; Baal, Jürgen van; Lammers, Aart ; Jansen, Christine A. - \ 2020
    Developmental and Comparative Immunology 114 (2020). - ISSN 0145-305X
    Chickens - Immune training - Lipopolysaccharide - Metabolism - Monocytes - β-glucan

    Recently, we have reported trained innate immunity in laying chicken monocytes. In the present study, we further investigated trained innate immunity of monocytes in layers and broilers. Monocytes of both breeds isolated from blood were trained in vitro with β-glucan, rec-chicken IL-4 or a combination of both, and restimulated with lipopolysaccharide (LPS), after which inflammation and metabolism-related responses were measured. Training of laying and broiler hen monocytes resulted in increased mRNA levels of IL-1β, iNOS and HIF-1α, but enhanced surface expression of CD40 and NO production was only observed in layers. Our in vitro study demonstrates that monocytes from different genetic backgrounds can be trained. However, the observed differences suggest a differential effect on immune functionality associated with innate training. Whether these differences in immune functions between layers and broilers have effect on disease resistance remains to be elucidated.

    The rin, nor and Cnr spontaneous mutations inhibit tomato fruit ripening in additive and epistatic manners
    Wang, Rufang ; Lammers, Michiel ; Tikunov, Yury ; Bovy, Arnaud G. ; Angenent, Gerco C. ; Maagd, Ruud A. de - \ 2020
    Plant Science 294 (2020). - ISSN 0168-9452
    Colorless non-ripening - Fruit ripening - non-ripening - ripening inhibitor - Spontaneous mutation - Tomato

    Tomato fruit ripening is regulated by transcription factors (TFs), their downstream effector genes, and the ethylene biosynthesis and signalling pathway. Spontaneous non-ripening mutants ripening inhibitor (rin), non-ripening (nor) and Colorless non-ripening (Cnr) correspond with mutations in or near the TF-encoding genes MADS-RIN, NAC-NOR and SPL-CNR, respectively. Here, we produced heterozygous single and double mutants of rin, nor and Cnr and evaluated their functions and genetic interactions in the same genetic background. We showed how these mutations interact at the level of phenotype, individual effector gene expression, and sensory and quality aspects, in a dose-dependent manner. Rin and nor have broadly similar quantitative effects on all aspects, demonstrating their additivity in fruit ripening regulation. We also found that the Cnr allele is epistatic to rin and nor and that its pleiotropic effects on fruit size and volatile production, in contrast to the well-known dominant effect on ripening, are incompletely dominant, or recessive.

    Early-life microbiota transplantation affects behavioural responses, serotonin and immune characteristics in chicken lines divergently selected on feather pecking
    Eijk, J.A.J. van der; Rodenburg, T.B. ; Vries, H.J.A. de; Kjaer, J.B. ; Smidt, H. ; Naguib, M. ; Kemp, B. ; Lammers, A. - \ 2020
    Scientific Reports 10 (2020). - ISSN 2045-2322 - 13 p.
    Gut microbiota influences host behaviour and physiology, such as anxiety, stress, serotonergic and immune systems. These behavioural and physiological characteristics are related to feather pecking (FP), a damaging behaviour in chickens that reduces animal welfare and productivity. Moreover, high FP (HFP) and low FP (LFP) lines differed in microbiota composition. However, it is unknown whether microbiota can influence the development of FP. For the first time, we identified the effects of microbiota transplantation on FP, and behavioural and physiological characteristics related to FP. HFP and LFP chicks received sterile saline (control), HFP or LFP microbiota transplantation during the first two weeks post-hatch. Microbiota transplantation influenced behavioural responses of the HFP line during treatment and of the LFP line after treatment. In both lines, homologous microbiota transplantation (i.e., receiving microbiota from their line) resulted in more active behavioural responses. Furthermore, microbiota transplantation influenced immune characteristics (natural antibodies) in both lines and peripheral serotonin in the LFP line. However, limited effects on microbiota composition, stress response (corticosterone) and FP were noted. Thus, early-life microbiota transplantation had immediate and long-term effects on behavioural responses and long-term effects on immune characteristics and peripheral serotonin; however, the effects were dependent on host genotype. Since early-life microbiota transplantation influenced behavioural and physiological characteristics that are related to FP, it could thus influence the development of FP later in life
    Gut microbiota affects behavioural responses of feather pecking selection lines
    Eijk, J.A.J. van der; Naguib, M. ; Kemp, B. ; Lammers, A. ; Rodenburg, T.B. - \ 2019
    In: Book of abstracts of the 70th Annual Meeting of the European Federation of Animal Science (EAAP). - Wageningen Academic Publishers (Book of Abstracts ) - ISBN 9789086863396 - p. 200 - 200.
    Early life environmental factors have a profound impact on an animal’s behavioural development. The gut microbiota could be such a factor as it inuences behavioural characteristics, such as stress and anxiety. Stress sensitivity and fearfulness are related to feather pecking (FP) in chickens, which involves pecking and pulling out feathers of conspecics. Furthermore, high (HFP) and low FP (LFP) lines differ in gut microbiota composition. Yet, it is unknown whether gut microbiota affects FP or behavioural characteristics related to FP. Therefore, HFP and LFP birds orally received a control, HFP or LFP microbiota treatment within 6 hrs post hatch and daily until 2 weeks of age. FP behaviour was observed via direct observations at pen-level between 0-5, 9-10 and 14-15 weeks of age. Birds were tested in novel object (3 days & 5 weeks of age), novel environment (1 week of age), open eld (13 weeks of age) and manual restraint (15 weeks of age) tests. Microbiota transplantation inuenced behavioural responses, but did not affect FP. HFP receiving HFP microbiota tended to approach a novel object sooner and more birds tended to approach than HFP receiving LFP microbiota at 3 days of age. HFP receiving HFP microbiota tended to vocalise sooner compared to HFP receiving control in a novel environment. LFP receiving LFP microbiota stepped and vocalised sooner compared to LFP receiving control in an open eld. Similarly, LFP receiving LFP microbiota tended to vocalise sooner during manual restraint than LFP receiving control or HFP microbiota. Thus, early life microbiota transplantation had short-term effects in HFP birds and long-term effects in LFP birds. Previously, HFP birds had more active responses compared to LFP birds. Thus, in this study HFP birds seemed to adopt behavioural characteristics of donor birds, but LFP birds did not. Interestingly, homologous microbiota transplantation resulted in more active responses, suggesting reduced fearfulness.
    The influence of genetic background on trained innate immunity in chicken macrophages
    Verwoolde, M.B. ; Biggelaar, Robin H.G.A. van den; Baal, J. van; Jansen, Christine A. ; Lammers, A. - \ 2019
    Short-term compensatory growth is observed after delayed nutrition in broiler chickens
    Hollemans, M.S. ; Lammers, A. ; Vries, S. de - \ 2019
    In: Proceedings of the 44th Animal Nutrition Research Forum. - - p. 22 - 23.
    Gut microbiota and feather pecking : Integrating microbiota, behaviour, stress, serotonin and the immune system
    Eijk, Jerine Alexandra Johanna van der - \ 2019
    Wageningen University. Promotor(en): M. Naguib; B. Kemp, co-promotor(en): T.B. Rodenburg; A. Lammers. - Wageningen : Wageningen University - ISBN 9789463951562 - 242

    Early-life factors can have a profound impact on an animal’s behavioural development. An important moment early in life is the rapid microbial colonization of the gut, leading to the establishment of the gut microbiota. From rodent studies it is clear that the gut microbiota influences host behaviour and physiology, such as anxiety, stress, and the serotonergic and immune systems. First indications show that microbiota affects similar behavioural and physiological characteristics in poultry. Through these effects microbiota could alter an animal’s ability to cope with environmental and social challenges, such as those encountered in animal production systems, and could thereby affect the development of damaging behaviours in production animals.

    Fearfulness, stress, and the serotonergic and immune systems have been related to severe feather pecking (FP), a damaging behaviour in chickens which involves pecking and pulling out feathers of conspecifics, negatively affecting animal welfare and productivity. Furthermore, high FP (HFP) and low FP (LFP) selection lines were shown to differ in gut microbial metabolites and microbiota composition determined from caecal droppings. These findings suggest a link between the gut microbiota and FP. Yet, it is unknown whether gut microbiota influences the development of FP. Therefore, the aim of this thesis was to identify effects of gut microbiota on the development of FP. First, I identified behavioural and physiological characteristics in FP genotypes (i.e. HFP and LFP lines) and FP phenotypes (i.e. feather pecker, victim, feather pecker-victim and neutral) that were related to FP and shown to be influenced by microbiota. Second, I identified whether microbiota influences FP, and behavioural and physiological characteristics related to FP.

    Feather pecking genotypes

    FP genotypes differed in behavioural responses, where HFP birds had more active behavioural responses compared to LFP birds (chapter 2, 3 and 6), especially at young age. The active behavioural responses suggest lower fearfulness, higher social and exploration motivation, or higher activity in HFP birds compared to LFP birds. For the stress response, HFP birds struggled later and less, but vocalized sooner and more compared to LFP birds during restraint (chapter 3 and 6). However, FP genotypes did not differ in corticosterone (CORT, the major stress hormone) level after restraint (chapter 3 and 6), suggesting differences in behavioural findings might not be related to stress. With regard to the serotonergic system, whole blood serotonin (5-Hydroxytryptamine or 5-HT) level was measured as indicator for central 5-HT and HFP birds had lower whole blood 5-HT levels compared to LFP birds (chapter 3 and 6). For the immune system, nitric oxide production by monocytes was measured as indicator for the innate immune system, specific antibody level was measured as part of the adaptive immune system, and natural (auto)antibody level was measured, as natural antibodies play an essential role in both innate and adaptive immunity. HFP birds had lower IgM and higher IgG natural (auto)antibody levels, higher nitric oxide production by monocytes, and a tendency for higher IgM and IgG specific antibody levels compared to LFP birds, but did not differ in relative abundances of immune cell subsets (chapter 3, 4 and 6). Moreover, FP genotypes had distinct luminal microbiota composition, where HFP birds had a higher relative abundance of genera of the order Clostridiales, but lower relative abundance of Lactobacillus compared to LFP birds (chapter 5). Yet, FP genotypes did not differ in mucosa-associated microbiota composition. In summary, these findings indicate that divergent selection on FP not only affects FP but also (in)directly affects behavioural responses, peripheral 5-HT level, different arms of the immune system and microbiota composition, but did not affect CORT level.

    Feather pecking phenotypes

    FP phenotypes differed in behavioural responses, where feather peckers tended to have more active behavioural responses compared to victims and neutrals at young age (chapter 2), which suggests lower fearfulness, higher exploration motivation or activity in feather peckers. Furthermore, victims had more active responses compared to neutrals at young age (chapter 2), which suggests lower fearfulness or higher activity in victims. For the stress response, feather peckers tended to have less active behavioural responses compared to neutrals, while victims had more active behavioural responses compared to other phenotypes during restraint (chapter 3). However, FP phenotypes did not differ in CORT level after restraint (chapter 3), suggesting differences in behavioural findings might not be related to stress. With regard to the serotonergic system, feather peckers had higher whole blood 5-HT levels compared to neutrals at adult age (chapter 3). However, FP phenotypes did not differ in natural antibody level (chapter 3) or gut microbiota composition (chapter 5). In summary, these findings indicate that performing and receiving FP is related to more active behavioural responses and that performing FP is further related to high peripheral 5-HT level.

    Feather pecking genotypes vs. phenotypes

    When comparing findings from FP genotypes to those from FP phenotypes, there is a similar relation between high FP and behavioural responses. HFP birds had more active responses compared to LFP birds (chapter 2, 3 and 6) and similarly feather peckers tended to have more active responses compared to victims and neutrals (chapter 2), especially at young age. Furthermore, victims had more active responses compared to other phenotypes at adult age (chapter 3). Thus, activity level might be used as potential indicator for FP at group level or even as indicator for individuals that perform or receive FP. Since feather peckers seem to have more active responses at young age (chapter 2), it would be interesting to identify whether activity level at young age could be used to predict which individuals will become feather peckers.

    There is an opposite relation between high FP and whole blood 5-HT level, where HFP birds had lower whole blood 5-HT levels compared to LFP birds (chapter 3 and 6), while feather peckers had higher whole blood 5-HT levels compared to neutrals (chapter 3). The actual performance of FP might increase peripheral 5-HT level in feather peckers, possibly due to feather eating. Feather peckers often ingest feathers, which may increase peripheral 5-HT level by providing structural components, as the gut releases 5-HT in reaction to these structural components. However, this relation between feather eating and increased peripheral 5-HT level needs further investigation.

    Similar to findings for FP genotypes, FP phenotypes did not differ in CORT level after restraint, indicating that the stress response might not be related to FP in FP genotypes and phenotypes. Furthermore, although differences between FP genotypes were found for the immune system and gut microbiota composition, no such differences were identified for FP phenotypes. This might indicate that differences in immune characteristics and gut microbiota composition are more related to genotype than to actual FP behaviour. Yet, cause and consequence cannot be disentangled from each other based on these findings. Therefore, microbiota transplantation was used to identify gut microbiota effects on the development of FP.

    Microbiota and the development of feather pecking

    Since FP genotypes differed in gut microbiota composition, but FP phenotypes did not, I focussed on FP genotypes for the second objective. The difference in microbiota composition was used to create a HFP and LFP microbiota pool. I identified effects of early-life microbiota transplantation on FP and on the same behavioural and physiological characteristics that were identified in chapter 2, 3 and 5. Newly hatched HFP and LFP chicks received a control treatment, HFP or LFP microbiota daily during the first two weeks post hatch.

    Although limited effects of early-life microbiota transplantation on microbiota composition were found, microbiota transplantation did affect behavioural responses, natural antibody level and whole blood 5-HT level. Thus, microbiota transplantation may have influenced brain, immune and serotonergic system functioning, which (in)directly resulted in differences in behavioural responses, natural antibody level and whole blood 5-HT level.

    With regard to behavioural responses, birds receiving microbiota from their own line (i.e. homologous transplantation) had more active behavioural responses compared to birds receiving microbiota from the other line or control treatment. These active behavioural responses suggest low fearfulness, high exploration and social motivation or activity in birds receiving homologous transplantation. For the stress response, LFP birds receiving homologous transplantation had more active stress responses compared to LFP birds that received HFP microbiota or control treatment. However, microbiota transplantation did not influence CORT level after restraint, suggesting these behavioural findings might not be related to stress.

    With regard to the serotonergic system, LFP birds receiving HFP microbiota tended to have lower whole blood 5-HT level compared to LFP birds receiving control treatment. Yet, microbiota transplantation effects on whole blood 5-HT level do not seem to be explained by the HFP pools’ microbiota composition. Especially since microbiota composition did not differ between treatments within the LFP line.

    For the immune system, birds receiving LFP microbiota had higher IgM natural antibody level compared to birds receiving control treatment, but microbiota transplantation did not affect IgG natural antibody level. Thus, being exposed to an adult microbiota composition might be sufficient to increase IgM natural antibody level. Further research is needed to identify whether microbiota transplantation could influence other immune characteristics in poultry, such as innate and adaptive immune characteristics.

    For the first time, effects of early-life microbiota transplantation on FP were investigated. However, early-life microbiota transplantation had limited effects on FP at young age (till 15 weeks of age) (chapter 6), which might be explained by FP usually increasing from the egg laying period onwards (around 20 weeks of age). Thus, further research is needed to identify effects of microbiota transplantation on FP at adult age.

    Effects of microbiota transplantation depend on genotype

    During treatment, microbiota transplantation influenced behavioural responses in the HFP line, while after treatment it influenced behavioural responses in the LFP line. A potential explanation for this could be that the HFP line has a more responsive immune system (chapter 3, 4 and 6), which responds more strongly to the environment or in this case to microbiota transplantation, with the synthesis and release of pro-inflammatory cytokines. These cytokines in turn act on the brain and alter neurotransmission, thereby potentially influencing behavioural responses. After treatment, microbiota transplantation influenced behavioural responses in the LFP line. These effects do not seem to be explained by the difference in whole blood 5-HT level. Still, it is interesting that LFP birds receiving HFP microbiota had lower whole blood 5-HT levels, as HFP birds had lower whole blood 5-HT levels compared to LFP birds (chapter 3 and 6). This might increase the risk for developing FP in LFP birds receiving HFP microbiota, as high FP is usually related to low whole blood 5-HT level. However, it remains unknown through which pathway microbiota transplantation influences behavioural responses in the LFP line.

    Homologous transplantation

    It is interesting to note that homologous transplantation resulted in birds having more active responses, suggesting reduced fearfulness. Therefore, homologous transplantation could be a potential approach to reduce fearfulness in chickens. High FP is usually related to high fearfulness, indicating that receiving homologous transplantation might reduce FP. Homologous transplantation might result in reduced fearfulness because of a match between transplanted microbiota composition and host genotype as opposed to a mismatch or control treatment. Homologous transplantation could be seen as a type of vertical transmission, where microbiota is transferred from mother hens to chicks. Vertical transmission might play an important role in initiating a host-specific gut microbiota, which might improve host immune system and brain development. Thus, homologous transplantation might have improved immune system and brain development, thereby altering behavioural responses. It would be interesting to identify whether homologous transplantation can be used to reduce fearfulness in poultry and FP in laying hens.

    Role for the immune system in feather pecking?

    There is increasing evidence for a role of the immune system in FP. For FP genotypes, HFP birds had higher specific antibody levels, IgG natural (auto)antibody levels and nitric oxide production by monocytes (chapter 3, 4 and 6), suggesting that high FP is related to a more responsive innate and adaptive immune system. Although it should be noted that FP phenotypes did not differ in natural antibody level (chapter 3). The immune system could be a potential route through which microbiota transplantation affects behavioural responses, especially in HFP birds as they seem to have a more responsive immune system (chapter 3, 4 and 6) and microbiota transplantation had immediate but no long-term effects on behavioural responses in HFP birds (chapter 6). Yet, the exact mechanisms through which the immune system affects the development of FP remain unknown, providing an interesting avenue for further research.

    Feather pecking selection lines as model system

    The HFP and LFP lines were used throughout this thesis as a model system to identify effects of gut microbiota on FP. As these lines are specifically selected on high and low FP, findings with regard to FP should be interpreted with caution when transferring them to other experimental or commercial lines. Overall, high FP was related to low fearfulness, low whole blood 5-HT level and a more responsive immune system in the FP selection lines (chapter 2-6). Previous studies in other experimental and commercial lines show that high FP is related to high fearfulness, low whole blood 5-HT level and a more responsive immune system. Findings with regard to CORT level after restraint are less consistent, with high FP being related to low CORT level after restraint or not. Thus, the FP selection lines seem to show similar relations between high FP, whole blood 5-HT level and immune responsiveness as commercial lines, but an opposite relation between high FP and fearfulness as other experimental and commercial lines. Furthermore, there is inconsistency with regard to the relation between high FP and the stress response. Therefore, findings from the FP selection lines should be used with caution when developing control or preventive methods that are to be applied in production systems. Still, this thesis provides new interesting insights into the relation between FP, behavioural and physiological characteristics related to FP and the gut microbiota.

    Conclusion

    Divergent selection on FP affects fearfulness, activity, peripheral serotonin, immune characteristics and gut microbiota composition, but not the physiological stress response (i.e. corticosterone). FP phenotypes differ in fearfulness, activity and peripheral serotonin, but not in the physiological stress response, immune characteristics or gut microbiota composition. Yet, relations between high FP and behavioural or physiological characteristics are not always similar for FP genotypes and phenotypes, indicating the importance of taking FP genotype and phenotype into account when studying FP.

    Gut microbiota could influence the development of FP, as early-life microbiota transplantation affects fearfulness, activity, peripheral serotonin and immune characteristics, with effects being either immediate or long-term. However, effects depend on age, donor’s and recipient’s genotype, indicating the importance of taking donor’s and recipient’s genotype into account when studying microbiota transplantation effects on behaviour. Overall, this thesis provides new interesting insights into the relationship between gut microbiota, host behaviour and physiology in poultry, which could further be of interest for other species.

    Chicken lines divergently selected on feather pecking differ in immune characteristics
    Eijk, Jerine A.J. van der; Verwoolde, Michel B. ; Vries Reilingh, Ger de; Jansen, Christine A. ; Rodenburg, Bas ; Lammers, Aart - \ 2019
    Physiology and Behavior 212 (2019). - ISSN 0031-9384
    Feather pecking - Immune system - Natural (auto)antibodies - Nitric oxide production - Specific antibodies

    It is crucial to identify whether relations between immune characteristics and damaging behaviors in production animals exist, as these behaviors reduce animal welfare and productivity. Feather pecking (FP) is a damaging behavior in chickens, which involves hens pecking and pulling at feathers of conspecifics. To further identify relationships between the immune system and FP we characterized high FP (HFP) and low FP (LFP) selection lines with regard to nitric oxide (NO) production by monocytes, specific antibody (SpAb) titers, natural (auto)antibody (N(A)Ab) titers and immune cell subsets. NO production by monocytes was measured as indicator for innate pro-inflammatory immune functioning, SpAb titers were measured as part of the adaptive immune system and N(A)Ab titers were measured as they play an essential role in both innate and adaptive immunity. Immune cell subsets were measured to identify whether differences in immune characteristics were reflected by differences in the relative abundance of immune cell subsets. Divergent selection on FP affected NO production by monocytes, SpAb and N(A)Ab titers, but did not affect immune cell subsets. The HFP line showed higher NO production by monocytes and higher IgG N(A)Ab titers compared to the LFP line. Furthermore the HFP line tended to have lower IgM NAAb titers, but higher IgM and IgG SpAb titers compared to the LFP line. Thus, divergent selection on FP affects the innate and adaptive immune system, where the HFP line seems to have a more responsive immune system compared to the LFP line. Although causation cannot be established in the present study, it is clear that relationships between the immune system and FP exist. Therefore, it is important to take these relationships into account when selecting on behavioral or immunological traits.

    Early life microbiota transplantation affects behaviour and peripheral serotonin in feather pecking selection lines
    Eijk, J.A.J. van der; Naguib, M. ; Kemp, B. ; Lammers, A. ; Rodenburg, T.B. - \ 2019
    In: Proceedings of the 53rd Congress of the International Society for Applied Ethology (ISAE). - Wageningen, The Netherlands : Wageningen Academic Publishers - ISBN 9789086863389 - p. 98 - 98.
    Early life environmental factors have a profound impact on an animal’s behavioural andphysiological development. In animal husbandry, early life factors that interfere with thebehavioural and physiological development could lead to the development of damagingbehaviours. The gut microbiota could be such a factor as it influences behaviour, such as stressand anxiety, and physiology, such as the serotonergic system. Stress sensitivity, fearfulness andserotonergic system functioning are related to feather pecking (FP), a damaging behaviourin chickens which involves pecking and pulling out feathers of conspecifics. Furthermore,high (HFP) and low FP (LFP) lines differ in gut microbiota composition. Yet, it is unknownwhether gut microbiota affects FP or behavioural and physiological characteristics related toFP. Therefore, HFP and LFP chicks orally received 100μL of a control, HFP or LFP microbiotatreatment within 6 hrs post hatch and daily until 2 weeks of age (n=96 per group) using apipette. FP behaviour was observed via direct observations at pen-level between 0-5, 9-10 and14-15 weeks of age. Birds were further tested in a novel object test at 3 days and 5 weeks of age,a novel environment test at 1 week of age, an open field test at 13 weeks of age and a manualrestraint test at 15 weeks of age after which whole blood was collected for serotonin analysis. Weanalysed treatment effects within lines using mixed models with treatment, batch, sex, observerand test time as fixed factors and pen within treatment as random factor or Kruskal-Wallistests. Early life microbiota transplantation influenced behavioural responses and peripheralserotonin, but did not affect FP. HFP receiving HFP microbiota tended to approach a novelobject sooner and more birds tended to approach than HFP receiving LFP microbiota at3 days of age (P<0.1). HFP receiving HFP microbiota tended to vocalise sooner comparedto HFP receiving control (P<0.1) in a novel environment. LFP receiving LFP microbiotastepped and vocalised sooner compared to LFP receiving control (P<0.05) in an open field.Similarly, LFP receiving LFP microbiota tended to vocalise sooner during manual restraintthan LFP receiving control or HFP microbiota (P<0.1). LFP receiving HFP microbiota tendedto have lower serotonin levels compared to LFP receiving control (P<0.1). Thus, early lifemicrobiota transplantation had short-term effects (during treatment) in HFP birds and longtermeffects (after treatment) in LFP birds. Previously, HFP birds had more active responsesand lower serotonin levels compared to LFP birds. Thus, in this study HFP birds seemed toadopt behavioural characteristics of donor birds, while LFP birds seemed to adopt physiologicalcharacteristics (i.e. serotonin level) of donor birds. Interestingly, homologous microbiotatransplantation resulted in more active responses, suggesting reduced fearfulness.
    Differences in gut microbiota composition of laying hen lines divergently selected on feather pecking
    Eijk, J.A.J. van der; Vries, H.J.A. de; Kjaer, Joergen B. ; Naguib, M. ; Kemp, B. ; Smidt, H. ; Rodenburg, T.B. ; Lammers, A. - \ 2019
    Poultry Science 98 (2019)12. - ISSN 0032-5791 - p. 7009 - 7021.
    Feather pecking (FP), a damaging behavior where laying hens peck and pull at feathers of conspecifics, is multifactorial and has been linked to numerous behavioral and physiological characteristics. The gut microbiota has been shown to influence host behavior and physiology in many species, and could therefore affect the development of damaging behaviors, such as FP. Yet, it is unknown whether FP genotypes (high FP [HFP] and low FP [LFP] lines) or FP phenotypes (i.e., individuals differing in FP, feather peckers and neutrals) differ in their gut microbiota composition. Therefore, we identified mucosa-associated microbiota composition of the ileum and cecum at 10 and 30 wk of age. At 30 wk of age, we further identified luminal microbiota composition from combined content of the ileum, ceca, and colon. FP phenotypes could not be distinguished from each other in mucosa-associated or luminal microbiota composition. However, HFP neutrals were characterized by a higher relative abundance of genera of Clostridiales, but lower relative abundance of Lactobacillus for the luminal microbiota composition compared to LFP phenotypes. Furthermore, HFP neutrals had a higher diversity and evenness for the luminal microbiota compared to LFP phenotypes. FP genotypes could not be distinguished from each other in mucosa-associated microbiota composition. Yet, FP genotypes could be distinguished from each other in luminal microbiota composition. HFP birds were characterized by a higher relative abundance of genera of Clostridiales, but lower relative abundance of Staphylococcus and Lactobacillus compared to LFP birds. Furthermore, HFP birds had a higher diversity and evenness for both cecal mucosa-associated and luminal microbiota compared to LFP birds at adult age. In conclusion, we here show that divergent selection on FP can (in)directly affect luminal microbiota composition. Whether differences in microbiota composition are causal to FP or a consequence of FP remains to be elucidated.
    Combining tree species and decay stages to increase invertebrate diversity in dead wood
    Andringa, Joke I. ; Zuo, Juan ; Berg, Matty P. ; Klein, Roy ; van't Veer, Jip ; Geus, Rick de; Beaumont, Marco de; Goudzwaard, Leo ; Hal, Jurgen van; Broekman, Rob ; Logtestijn, Richard S.P. van; Li, Yikang ; Fujii, Saori ; Lammers, Mark ; Hefting, Mariet M. ; Sass-Klaassen, Ute ; Cornelissen, Johannes H.C. - \ 2019
    Forest Ecology and Management 441 (2019). - ISSN 0378-1127 - p. 80 - 88.
    Biodiversity - Chilipoda - Coarse woody debris - Coleoptera - Diplopoda - Habitat heterogeneity - Invertebrates - Isopoda - Managed forest - Wood decomposition

    Dead wood availability and the variability in dead wood quality, i.e. tree species and decay stages, are often low in managed forests, which negatively affects biodiversity of invertebrate species. Leaving more (coarse) dead wood can increase invertebrate richness, but it remains unclear how many and which combinations of tree taxa and decay stages are required to optimize niche heterogeneity in managed forests. We investigated the diversity of the main arthropod groups associated with dead wood, i.e. millipedes, centipedes, isopods and beetles, through the first four years of decomposition of logs of twenty common temperate tree species placed in the “common garden” experiment LOGLIFE. We hypothesized that (1) invertebrate richness for combinations of a given number of tree species would be promoted by mixing both tree species and decay period and that (2) invertebrate richness increases up to a saturation point with more tree species at different decay stages added. We also hypothesized that (3) an increase in phylogenetic distance among the tree species in combinations would promote their overall invertebrate diversity. We found that the better combinations, in terms of invertebrate richness, after one and two years of decay, but not after four years, consisted of a mix of gymnosperms and angiosperms, indicating that variation in tree species is especially important during the initial decomposition period. The best combinations in terms of invertebrate richness consisted of at least one tree species from each decay period, indicating that also variation in the decay stage of the tree is important to promote invertebrate diversity. We observed that at least four wood types were required to approach the 95% saturation point for species richness. The third hypothesis, that dissimilarity in phylogenetic position could be a predictive tool for increasing invertebrate richness in combinations of tree species, was not supported by our results. Thus, in order to maintain diversity of dead wood invertebrates in forests we recommend not only to provide richness in tree species, but also to plant particular combinations of trees (preferably angiosperm-gymnosperm combinations) that differ in the invertebrate communities they typically host and to temporally spread the logging of trees. This way the logging residues cover different resources and habitats at each moment in time, which is likely to result in a large diversity of dead wood invertebrates.

    Early-life microbiota transplantation affects behavioural responses of chicken lines divergently selected on feather pecking
    Eijk, J.A.J. van der; Lammers, A. ; Kemp, B. ; Naguib, M. ; Rodenburg, T.B. - \ 2019
    In: Trade-offs in science – keeping the Balance. - Wageningen University & Research - p. 17 - 17.
    Trained innate immunity in chicken macrophages
    Verwoolde, M.B. ; Biggelaar, Robin H.G.A. van den; Baal, J. van; Jansen, Christine A. ; Lammers, A. - \ 2019
    In: Trade-offs in science – keeping the Balance. - Wageningen University & Research - p. 27 - 27.
    Re-evaluation of transcription factor function in tomato fruit development and ripening with CRISPR/Cas9-mutagenesis
    Wang, Rufang ; Rocha Tavano, Eveline Carla da; Lammers, Michiel ; Martinelli, Adriana Pinheiro ; Angenent, Gerco C. ; Maagd, Ruud A. de - \ 2019
    Scientific Reports 9 (2019)1. - ISSN 2045-2322

    Tomato (Solanum lycopersicum) is a model for climacteric fleshy fruit ripening studies. Tomato ripening is regulated by multiple transcription factors together with the plant hormone ethylene and their downstream effector genes. Transcription Factors APETALA2a (AP2a), NON-RIPENING (NOR) and FRUITFULL (FUL1/TDR4 and FUL2/MBP7) were reported as master regulators controlling tomato fruit ripening. Their proposed functions were derived from studies of the phenotype of spontaneous mutants or RNAi knock-down lines rather than, as it appears now, actual null mutants. To study TF function in tomato fruit ripening in more detail, we used CRISPR/Cas9-mediated mutagenesis to knock out the encoding genes, and phenotypes of these mutants are reported for the first time. While the earlier ripening, orange-ripe phenotype of ap2a mutants was confirmed, the nor null mutant exhibited a much milder phenotype than the spontaneous nor mutant. Additional analyses revealed that the severe phenotype in the spontaneous mutant is caused by a dominant-negative allele. Our approach also provides new insight into the independent and overlapping functions of FUL1 and FUL2. Single and combined null alleles of FUL1 and FUL2 illustrate that these two genes have partially redundant functions in fruit ripening, but also unveil an additional role for FUL2 in early fruit development.

    Stress response, peripheral serotonin and natural antibodies in feather pecking genotypes and phenotypes and their relation with coping style
    Eijk, Jerine A.J. van der; Lammers, Aart ; Kjaer, J.B. ; Rodenburg, T.B. - \ 2019
    Physiology and Behavior 199 (2019). - ISSN 0031-9384 - p. 1 - 10.
    Feather pecking - genotype - natural antibody - phenotype - serotonin - stress response

    Feather pecking (FP), a serious welfare and economic issue in the egg production industry, has been related to coping style. Proactive and reactive coping styles differ in, among others, the stress response, serotonergic activity and immune activity. Yet, it is unknown whether genetic lines divergently selected on FP (i.e. FP genotypes) or individuals differing in FP (i.e. FP phenotypes) can be categorized into coping styles. Therefore, we determined peripheral serotonin (5-HT) levels, natural antibody (NAb) titers, behavioral and corticosterone (CORT) responses to manual restraint (MR) in FP genotypes (high FP (HFP), low FP (LFP) and unselected control (CON) line) and FP phenotypes (feather pecker, feather pecker-victim, victim and neutral). We further examined the consistency of and relationships between behavioral and physiological measures. FP genotypes differed in behavioral responses to MR, 5-HT levels and NAb titers, but not in CORT levels after MR. HFP birds had less active responses at adolescent age, but more active responses at adult age compared to LFP and CON birds. The CON line had higher 5-HT levels at adolescent age, while the HFP line had lower 5-HT levels than the other lines at adult age. Overall, the HFP line had lower IgM NAb titers, while the LFP line had lower IgG NAb titers compared to the other lines. FP phenotypes differed in behavioral responses to MR and 5-HT levels, but not in CORT levels after MR or NAb titers. Within the HFP line, feather peckers tended to have less active responses compared to neutrals at adolescent age, while victims had more active responses compared to the other phenotypes at adult age. Feather peckers had higher 5-HT levels than neutrals at adult age. Behavioral and CORT responses to MR were not consistent over time, suggesting that responses to MR might not reflect coping style in this study. Furthermore, proactive behavioral responses were correlated with reactive physiological measures and vice versa. Thus, it was not possible to categorize FP genotypes or FP phenotypes into specific coping styles.

    Feather pecking phenotype affects behavioural responses of laying hens
    Eijk, J.A.J. van der; Lammers, A. ; Rodenburg, T.B. - \ 2018
    In: Proceedings of the 52nd Congress of the International Society for Applied Ethology. - Wageningen, The Netherlands : Wageningen Academic Publishers - ISBN 9789086863228 - p. 169 - 169.
    Feather pecking (FP) is a major welfare and economic issue in the egg production industry. It involves hens pecking and pulling at feathers of conspecics, thereby negatively aecting welfare. Behavioural characteristics, such as fearfulness, have been related to FP. Although many studies have identied dierences in fearfulness between lines that dier in FP, the relationship between actual FP behaviour (i.e. FP phenotypes) and fearfulness is not well understood. erefore, we compared responses of birds with diering FP phenotypes to several behavioural tests at young and adult ages. We used birds from a genetic line selected for high feather pecking. FP phenotypes of individual birds were identied via FP observations at 3-4, 12-13, 15-16 and 28-29 weeks of age. e total number of severe feather pecks (SFP) given and received over two subsequent weeks was used to categorize birds as feather peckers (P, SFP given >1), feather pecker-victims (P-V, SFP given and received >1), victims (V, SFP received >1) or neutrals (N, SFP given and received 0 or 1) at each age point. Birds were tested individually in a novel environment (NE) test at 4 weeks of age, an open eld (OF) test at 15 weeks of age and a tonic immobility (TI) test at 13 and 28 weeks of age. Experimenters were blinded to the phenotypes. Data were analysed using linear mixed models, with phenotype and batch as xed factors and pen as a random factor. Test time was added as a xed eect for the NE and OF test. Experimenter was added as a xed eect for the NE and TI test. Testing order was included as a xed eect for the TI test. Phenotype eects were tested for each behavioural test and age separately using the most recent FP phenotype categorization. FP phenotype aected the number of ight attempts (F3, 119=3.18, P<0.05) during the NE test, where victims showed more ight attempts compared to neutrals (V=2.3 vs n=1.6; P<0.05) and tended to show fewer ight attempts compared to feather peckers (V=2.3 vs P=2.7; P<0.1). FP phenotype further tended to aect step frequency (F3, 75=2.64, P<0.1) during the OF test, where feather peckers tended to walk more compared to neutrals (P=24.6 vs n=15.7; P<0.1). No FP phenotype eects were found for the TI test. Feather peckers tended to show more active responses (i.e. tended to show more ight attempts compared to victims and tended to walk more compared to neutrals), which could suggest lower fearfulness, compared to victims at 4 weeks of age and compared to neutrals at 15 weeks of age. ese ndings give rst indications that FP phenotypes seem to dier in fearfulness. It should be noted that we only found dierences in the NE and OF test, where behavioural responses could also be related to activity or coping style. Further research is needed to identify whether FP phenotypes dier in activity and whether they can be classied into dierent coping styles.
    In vitro model to study trained innate immunity in chicken primary monocytes
    Verwoolde, M.B. ; Biggelaar, Robin H.G.A. van den; Baal, J. van; Jansen, Christine A. ; Lammers, A. - \ 2018
    Early-life microbiota transplantation affects behavioural responses in feather pecking selection lines
    Weetering, Y. van de; Eijk, J.A.J. van der; Lammers, A. ; Rodenburg, T.B. - \ 2018
    Feather pecking (FP) is a major welfare and economic problem in the laying hen industry, as it can cause feather damage and could lead to injuries or even mortality of victims. FP is multifactorial and has been related to behaviours such as fearfulness. Gut microbiota might contribute to FP, as it influences behaviours in rodent models that have been linked to FP such as anxiety. Moreover, recent studies have found that high and low FP lines differ in their cecal microbial metabolites and composition. However, it is unknown whether a causal link between the gut microbiota and FP exists. Therefore, we orally administered adult microbiota to newly hatched chicks (daily, day 0-14 of age). We used genetic lines selected for high (HFP, n = 288) and low (LFP, n = 288) FP. The microbiota transplants were collected from pooled gut content of 30 week old HFP and LFP donor birds. Each line received either HFP microbiota, LFP microbiota or control treatment. FP behaviour was observed via direct observations on pen-level between 0-5, 8-10 and 13-15 weeks of age. Furthermore, birds were tested in two behavioural tests; the Novel Object (NO) test at 3 days and 5 weeks of age and the Open Field (OF) test at 13 weeks of age. Although we did not find an effect of line*treatment interactions or treatment on FP, we did observe that birds treated with LFP microbiota stepped sooner (P < 0.01) and more and vocalized sooner compared to the control treated birds during the OF test (P < 0.05). Additionally, they stepped sooner during the OF, yet took longer to approach the NO compared to HFP microbiota groups (P < 0.05). Therefore, we conclude that early-life microbiota treatment affects behavioural responses, which might be related to fearfulness, social motivation or coping style.
    Protein fermentation profiles in pigs
    Lammers-Jannink, Kim - \ 2018
    Growth rate of broiler chickens is influenced by early life feeding strategy
    Hollemans, M.S. ; Lammers, A. ; Vries, S. de - \ 2018
    In: The XVth European Poultry Conference (EPC). - Zagreb, Croatia : - ISBN 9789082915709 - p. 579 - 579.
    delayed nutrition - early nutrition - Intestinal permeability - compensatory growth
    After hatching in conventional systems, broiler chickens have a delay to nutrition thatcan last for 72h, depending on length of the hatch window, internal hatchery proceduresand transport duration. Previous research on early life feeding strategies has shownnegative effects on bodyweight (BW) gain after delayed nutrition (DN), compared withearly nutrition (EN). However, it is not known whether DN chickens can (partially)compensate for their lower BW between hatch and slaughter. In this study, we tested thehypothesis that DN chickens have an increased growth rate, as a result of compensatorygrowth. Data from 3 independent experiments were used. In these studies, broilerswere subjected to either EN or DN with different durations of DN (38 to 72 h) and daysto slaughter (14 to 35 d). In all experiments, DN groups had lower BW compared withEN which was sustained until slaughter. Relative differences in BW, however, decreasedfrom 114 to 176% post placement to 102 – 112 % at slaughter (35 d). Growth curves of DNand EN chickens were analysed to study whether compensatory growth could explain thedifferences in BW between EN and DN. Absolute average daily gain (aADG) was higher inEN chickens from start until slaughter. To analyse the growth curve independent of BW,relative ADG (rADG) between two ages was calculated as follows:Differences in rADG between DN and EN chickens were greater in the first 14 d (DN:63%, EN: 47%; P < 0.001), but smaller in the remaining grow-out period (14 – 28 d:DN: 18%, EN: 16%; 28 – 35 d: DN: 8%, EN: 7%; both P <0 .001). Based on these results,it seems that DN broilers compensate for their lag in BW during the first 14 d postplacement. As differences in absolute BW were still present at 35 d, the increase in rADGseems insufficient to catch up with EN broilers. EN chickens have higher aADG untilslaughter, however, rADG is lower, showing that growth rate is influenced by feedingstrategy. Previous literature describes interactions between compensatory growth andnutrient composition of diets on nitrogen and fat retention. This may give reason forfuture work to evaluate effects of early life feeding strategy on carcass traits.
    Body weight is affected by early life feeding strategy and hatch moment in broiler chickens
    Hollemans, M.S. ; Noorloos, Marit ; Vries, S. de; Lammers, A. - \ 2018
    In: The XVth European Poultry Conference (EPC). - Zagreb, Croatia : - ISBN 9789082915709 - p. 259 - 259.
    delayed nutrition - early nutrition - Intestinal permeability - compensatory growth
    After hatching in conventional systems, broiler chickens have a delay to nutrition that can last for 72h, depending on length of the hatch window, internal hatchery procedures and transport duration. Previous research on early life feeding strategies has shown negative effects on bodyweight (BW) gain after delayed nutrition (DN), compared with early nutrition (EN). However, it is not known whether DN chickens can (partially)compensate for their lower BW between hatch and slaughter. In this study, we tested the hypothesis that DN chickens have an increased growth rate, as a result of compensatory growth. Data from 3 independent experiments were used. In these studies, broilers were subjected to either EN or DN with different durations of DN (38 to 72 h) and days to slaughter (14 to 35 d). In all experiments, DN groups had lower BW compared withEN which was sustained until slaughter. Relative differences in BW, however, decreased from 114 to 176% post placement to 102 – 112 % at slaughter (35 d). Growth curves of DN and EN chickens were analysed to study whether compensatory growth could explain the differences in BW between EN and DN. Absolute average daily gain (aADG) was higher in EN chickens from start until slaughter. To analyse the growth curve independent of BW, relative ADG (rADG) between two ages was calculated as follows: Differences in rADG between DN and EN chickens were greater in the first 14 d (DN:63%, EN: 47%; P < 0.001), but smaller in the remaining grow-out period (14 – 28 d:DN: 18%, EN: 16%; 28 – 35 d: DN: 8%, EN: 7%; both P <0 .001). Based on these results,it seems that DN broilers compensate for their lag in BW during the first 14 d postplacement. As differences in absolute BW were still present at 35 d, the increase in rADG seems insufficient to catch up with EN broilers. EN chickens have higher aADG until slaughter, however, rADG is lower, showing that growth rate is influenced by feeding strategy. Previous literature describes interactions between compensatory growth and nutrient composition of diets on nitrogen and fat retention. This may give reason for future work to evaluate effects of early life feeding strategy on carcass traits.
    Learning by Creating a MOOC
    Frederiks, Gwenda ; Mirck, Sanne ; Stalpers, Serge ; Lammers, Sietske - \ 2018
    In: Proceedings of 2018 Learning With MOOCS, LWMOOCS 2018. - Institute of Electrical and Electronics Engineers Inc. - ISBN 9781538665336 - p. 127 - 130.
    MOOC - OER - open pedagogy - skills development - student-created MOOC

    Massive Open Online Courses (MOOCs) can be a platform for campus students to publish co-created educational material. Involving students in the creation of a MOOC has the potential to lead to a more learner-centered MOOC while also providing students with the opportunity to gain skills. This exploratory case study evaluates that potential. We analyze the learning gains of the students, the MOOC they created (the product), and our own support during the development process. Analysis shows that the MOOC had a similar quality to our other MOOCs. Videos and assignments were more creative than usual, but were not created with a much more learner-centered focus. The students gained valuable skills while making the MOOC, such as leadership skills and video presenting skills. The support from university staff was seen as very valuable, but could have been expanded to truly elevate the quality of the content. We end this paper with some practical recommendations for other teams wishing to help students create a MOOC.

    Exploring practice based theories for health promotion among families with low socio-economic status
    Hogeling, L. ; Crijns-Lammers, Christianne ; Vaandrager, L. ; Koelen, M.A. - \ 2018
    Ant-like Traits in Wingless Parasitoids Repel Attack from Wolf Spiders
    Harvey, Jeffrey A. ; Visser, Bertanne ; Lammers, Marl ; Marien, Janine ; Gershenzon, Jonathan ; Ode, Paul J. ; Heinen, Robin ; Gols, Rieta ; Ellers, Jacintha - \ 2018
    Journal of Chemical Ecology 44 (2018)10. - ISSN 0098-0331 - p. 894 - 904.
    Batesian mimicry; Müllerian mimicry - Chemical defense - Formica - Gelis - Hymenoptera - Lasius - Predation

    A recent study showed that a wingless parasitoid, Gelis agilis, exhibits a suite of ant-like traits that repels attack from wolf spiders. When agitated, G. agilis secreted 6-methyl-5-hepten-2-one (sulcatone), which a small number of ant species produce as an alarm/panic pheromone. Here, we tested four Gelis parasitoid species, occurring in the same food chain and microhabitats, for the presence of sulcatone and conducted two-species choice bioassays with wolf spiders to determine their degree of susceptibility to attack. All four Gelis species, including both winged and wingless species, produced sulcatone, whereas a closely related species, Acrolyta nens, and the more distantly related Cotesia glomerata, did not. In two-choice bioassays, spiders overwhelmingly rejected the wingless Gelis species, preferring A. nens and C. glomerata. However, spiders exhibited no preference for either A. nens or G. areator, both of which are winged. Wingless gelines exhibited several ant-like traits, perhaps accounting for the reluctance of spiders to attack them. On the other hand, despite producing sulcatone, the winged G. areator more closely resembles other winged cryptines like A. nens, making it harder for spiders to distinguish between these two species. C. glomerata was also preferred by spiders over A. nens, suggesting that other non-sulcatone producing cryptines nevertheless possess traits that make them less attractive as prey. Phylogenetic reconstruction of the Cryptinae reveals that G. hortensis and G. proximus are ‘sister’species, with G. agilis, and G.areator in particular evolving along more distant trajectories. We discuss the possibility that wingless Gelis species have evolved a suite of ant-like traits as a form, of mimicry to repel predators on the ground.

    Feather pecking genotype and phenotype affect behavioural responses of laying hens
    Eijk, Jerine A.J. van der; Lammers, Aart ; Li, Peiyun ; Kjaer, Joergen B. ; Rodenburg, T.B. - \ 2018
    Applied Animal Behaviour Science 205 (2018). - ISSN 0168-1591 - p. 141 - 150.
    Activity - Coping style - Fearfulness - Feather pecking - Genotype - Phenotype

    Feather pecking (FP) is a major welfare and economic issue in the egg production industry. Behavioural characteristics, such as fearfulness, have been related to FP. However, it is unknown how divergent selection on FP affects fearfulness in comparison to no selection on FP. Therefore, we compared responses of birds selected on low (LFP) and high feather pecking (HFP) with birds from an unselected control line (CON) to several behavioural tests (i.e. novel object (NO), novel environment (NE), open field (OF) and tonic immobility (TI)) at young and adult ages. Furthermore, the relation between actual FP behaviour (i.e. FP phenotypes) and fearfulness is not well understood. Therefore, we compared responses of birds with differing FP phenotypes. Feather pecking phenotypes of individual birds were identified via FP observations at several ages. The number of severe feather pecks given and received was used to categorize birds as feather peckers, feather pecker-victims, victims or neutrals. Here we show that HFP birds repeatedly had more active responses (i.e. they approached a NO sooner, vocalized sooner and more, showed more flight attempts and had shorter TI durations), which could indicate lower fearfulness, compared to CON and LFP birds at both young and adult ages. Within the HFP line, feather peckers had more active responses (i.e. they tended to show more flight attempts compared to victims and tended to walk more compared to neutrals), suggesting lower fearfulness, compared to victims and neutrals. Thus, in this study high FP seems to be related to low fearfulness, which is opposite to what previously has been found in other experimental and commercial lines. This stresses the need for further research into the genetic and phenotypic correlations between FP and fearfulness in various populations of chickens, especially in commercial lines. Findings from experimental lines should be used with caution when developing control and/or prevention methods that are to be applied in commercial settings. Furthermore, activity and/or coping style might overrule fearfulness within the HFP line, as HFP birds and feather peckers within the HFP line had more active responses. This might indicate a complex interplay between fearfulness, activity and coping style that could play a role in the development of FP.

    Effects of early feeding and dietary interventions on development of lymphoid organs and immune competence in neonatal chickens : A review
    Taha-Abdelaziz, Khaled ; Hodgins, Douglas C. ; Lammers, Aart ; Alkie, Tamiru Negash ; Sharif, Shayan - \ 2018
    Veterinary Immunology and Immunopathology 201 (2018). - ISSN 0165-2427 - p. 1 - 11.
    Antimicrobial peptides - Chicken - Dietary supplementation - Early feeding - Feed additives - Heat stress - Immune system - In ovo feeding - Lymphoid organs - Nanoparticles - Phytobiotics - Prebiotics - Probiotics - TLR ligands
    With the ongoing intensification of the poultry industry and the continuous need to control pathogens, there is a critical need to extend our understanding of the avian immune system and the role of nutritional interventions on development of immune competence in neonatal chicks. In this review, we will focus on the ontogeny of the lymphoid organs during embryonic life and the first 2 weeks post-hatch, and how early feeding practices improve heath and modulate the development and function of the immune system in young chicks. The evidence for the positive impact of the nutrition of breeder hens on embryonic development and on the survival and immunity of their chicks will also be outlined. Additionally, we will discuss the vital role of supplemental feeding either in ovo or immediately post-hatch in chick health and immunity and the importance of these approaches in ameliorating immune system functions of heat-stressed chicks. To conclude, we provide some perspectives on a number of key issues, concerning the mechanisms of nutritional modulation of immunity, that need to be addressed. A thorough investigation of these mechanisms may assist in the formulation of diets to improve the immunity and general health status.
    Effects of early nutrition and transport of 1-day-old chickens on production performance and fear response
    Hollemans, M.S. ; Vries, S. de; Lammers, A. ; Clouard, C.M. - \ 2018
    Poultry Science 97 (2018)7. - ISSN 0032-5791 - p. 2534 - 2542.
    broiler - chicken - early nutrition - transport - behavior - production performance
    The importance of optimal early life conditions of broilers to sustain efficient and healthy production of broiler meat is increasingly recognized. Therefore, novel husbandry systems are developed, in which immediate provision of nutrition post hatch is combined with on-farm hatching. In these novel systems, 1-day-old-chick handling and transport are minimized. To study whether early nutrition and reduced transport are beneficial for broiler performance and behavior, the effects of early or delayed nutrition and post-hatch handling and transport were tested from hatch until 35 d of age, in a 2 × 2 factorial arrangement. In total, 960 eggs were hatched in 36 floor pens. After hatch, chicks were given immediate access to water and feed (early nutrition) or after 54 h (delayed nutrition). Eighteen hours after hatch, chicks remained in their pens (non-transported control), or were subjected to short-term handling and transport to simulate conventional procedures. Subsequently, chicks returned to their pens. Compared with delayed-fed chickens, early-fed chickens had greater body weight up to 21 d of age, but not at slaughter (35 d of age). No effects of transport or its interaction with moment of first nutrition were found on performance. At 3 d post hatch, transported, early-fed chicks had a greater latency to stand up in a tonic immobility test than transported, delayed-fed chicks, but only in chicks that were transported. At 30 d post hatch, however, latency was greater in transported, delayed-fed chickens than in transported, early-fed chicks. This may indicate long-term deleterious effects of delayed nutrition on fear response in transported chickens. It is concluded that early nutrition has mainly beneficial effects on performance during the first 2 wk post hatch, but these beneficial effects are less evident in later life. The combination of transport and early nutrition may influence the chicken's strategies to cope with stressful events in early and later life.
    Early life feeding strategy and hatch moment affects early life body weight development
    Hollemans, M.S. ; Noorloos, Marit ; Vries, S. de; Lammers, A. - \ 2018
    In: Abstract of the WIAS Science Day 2018. - - p. 28 - 28.
    Antigen-dependent effects of divergent selective breeding based on natural antibodies on specific humoral immune responses in chickens
    Berghof, T.V.L. ; Arts, J.A.J. ; Bovenhuis, H. ; Lammers, A. ; Poel, J.J. van der; Parmentier, H.K. - \ 2018
    Vaccine 36 (2018)11. - ISSN 0264-410X - p. 1444 - 1452.
    Breeding - Chicken - General disease resistance - Keyhole limpet hemocyanin (KLH) - Natural antibody - Specific antibody
    NAb are defined as antigen binding antibodies present without a known previous exposure to this antigen. NAb are suggested to enhance specific antibody (SpAb) responses, but consequences of different NAb levels on immunization are largely unknown. Layer chickens were divergently selected and bred for keyhole limpet hemocyanin (KLH)-binding NAb titers, resulting in a High line and a Low line. In this study, we investigated: (1) the relation of NAb levels with SpAb titers; and (2) the effect of immunization on NAb titers. The 50 highest females of the High line and the 50 lowest females of the Low line of generation 2 were intramuscularly immunized at 33 weeks of age with 1 mL phosphate buffered saline (PBS) containing one of four treatments: (1) negative control (no antigen), (2) 500 μg KLH, (3) 100 μg avian tuberculin purified protein derivative of Mycobacterium avium (PPD), or (4) 250 μg human serum albumin (HuSA). IgM and IgG titers of NAb and SpAb in plasma were determined prior to immunization and weekly for 5 weeks post immunization by indirect ELISA. In addition, antibody affinity was investigated. No differences in SpAb and NAb response against KLH and PPD were observed as a consequence of different NAb titers, but increased and prolonged SpAb and NAb titer responses against HuSA were observed for the High line compared to the Low line. Different natural antibody titers did not impair SpAb dynamics and SpAb affinity. NAb titers were not, or for only short-term, affected by immunization. We show here that NAb may enhance SpAb responses, but that this effect is antigen-dependent. We hypothesize that NAb play a role in general disease resistance through enhancement of the humoral adaptive immune response.
    Effect of butyrate concentration in the GIT on innate and adaptive immune responses of broilers
    Moquet, P.C.A. ; Konnert, G.D.P. ; Lammers, A. ; Onrust, L. ; Kwakkel, R.P. - \ 2017
    Abstract #25757
    Early nutrition strategy and transport play a role in the development of fear response and production performance
    Hollemans, M.S. ; Vries, S. de; Lammers, A. ; Clouard, C.M. - \ 2017
    - p. 55 - 56.
    Behavioural and physiological characterisation of laying hen lines divergently selected on feather pecking
    Eijk, J.A.J. van der; Lammers, A. ; Rodenburg, T.B. - \ 2017
    In: Xth European Symposium on Poultry Welfare, 19-22 June 2017, Ploufragan - France. - World's Poultry Science Association (WPSA) - p. 60 - 60.
    broiler breeders - nesting behaviour - genetics - nest design - housing - climate - laying hens - feather pecking - fearfulness - coping style - stress - imune system
    Broilers have been selected for growth related characteristics, which are negatively correlated to reproductive traits. This genetic background creates challenges in broiler breeders, as the hens do not make optimal use of the nests provided. This project aims to investigate what factors determine nesting behaviour, i.e. where a broiler breeder hen prefers to lay her eggs. Factors such as genetic background, social interactions, physical characteristics of the nest and climate might interfere with the natural nesting behaviour of the hen. Also fundamental trade-offs between different motivations, such as hunger, comfort and safety, might influence nesting behaviour. Behaviour and use of space will be measured in experimental set-ups in order to gain insight in the importance of different system components. This knowledge will be used to optimise housing conditions and develop strategies that stimulate the hen to lay her egg in the nest. The performance of this improved system will be tested in field experiments to investigate the transferability of results from experimental to field conditions.
    Feather pecking: is it in the way hens cope with stress?
    Eijk, J.A.J. van der; Rodenburg, T.B. ; Lammers, A. - \ 2017
    In: Proceedings of the 51st Congress of the International Society for Applied Ethology (ISAE), 7-10 August 2017, Aarhus, Denmark. - Wageningen : Wageningen Academic Publishers - ISBN 9789086863112 - p. 139 - 139.
    animal welfare - animal behaviour


    Effects of early nutrition and transport of one-day-old chickens on production performance and behavior
    Hollemans, M.S. ; Vries, S. de; Lammers, A. ; Clouard, C.M. - \ 2017
    In: Abstract of the WIAS Science Day 2017: Beyond Sustainability. - - p. 9 - 9.
    Nutrition of pigs kept under low and high sanitary conditions : effects on animo acid and energy metabolism and damaging behaviour
    Meer, Yvonne van der - \ 2017
    Wageningen University. Promotor(en): W.J.J. Gerrits, co-promotor(en): A.J.M. Jansman; A. Lammers. - Wageningen : Wageningen University - ISBN 9789463431972 - 181
    pigs - feeds - pig feeding - animal nutrition - amino acid metabolism - animal health - energy metabolism - abnormal behaviour - behaviour disorders - immune system - nutrition physiology - varkens - voer - varkensvoeding - diervoeding - aminozuurmetabolisme - diergezondheid - energiemetabolisme - abnormaal gedrag - gedragsstoornissen - immuunsysteem - voedingsfysiologie

    It is economically and environmentally important to match the nutrient supply to the nutrient requirements in pig production. Until now, the effects of different sanitary conditions on energy and nutrient requirements are not implemented in recommendations for nutrient composition of pig diets. The current nutrient requirement data are based on studies with pigs in experimental settings, which can be regarded as rather optimal. Changes in nutrient requirements caused by differences in sanitary conditions are poorly documented. As in the pig production sector farm conditions are variable it is of major importance to determine the effects of low sanitary conditions (LSC) on requirements for amino acids and energy in growing pigs. Pigs under LSC have an increased risk of clinical and subclinical infections, resulting in a chronic stimulation of their immune system. Immune system stimulation is known to influence energy and amino acid metabolism. However, most studies in pigs evaluating the relationship between immune system stimulation and nutrient requirements often use specific experimental challenge models. Whereas such models have the obvious advantage of reproducibility and allow mechanistic insight in the effects of stimulating specific parts of the immune system, these models often induce clinical illness, rather than subclinical infections. Results obtained with such models may therefore be difficult to translate to practical situations. Therefore the objective of the present thesis was to study the effect of low and high sanitary conditions (HSC) on amino acids and energy metabolism in pigs. Also interactions between the immune system, nutrient metabolism and damaging behaviour of pigs were considered in this thesis.

    The experiment described in Chapter 2 was designed to study the effect of different dietary crude protein levels and extra amino acid supplementation on the growth performance of pigs kept under different sanitary conditions. In a 2×2×2 factorial arrangement, 68 groups of 9 pigs were allocated to either LSC or HSC, and were offered ad libitum access to two different diets, a normal crude protein concentration diet or a low crude protein concentration diet, each having either a basal dietary amino acid profile or supplemented dietary amino acid profile containing 20% more methionine, threonine, and tryptophan compared with the basal profile. The pigs were followed from 10 weeks of age until slaughter. Haptoglobin concentrations in serum and IgG antibody titers against keyhole limpet heamocyanin, collected in the starter, grower, and finisher phases, and pleuritis scores at slaughter were greater for LSC pigs compared with HSC pigs, illustrating that sanitary conditions affected health conditions. The average daily gain and gain to feed ratio were greater for HSC pigs compared with LSC pigs. A 20% increase in dietary supplementation of methionine, threonine, and tryptophan relative to lysine increased gain to feed ratio more in LSC than in HSC pigs. The results therefore illustrated that dietary requirements for methionine. threonine, and tryptophan were greater for LSC compared with HSC pigs.

    In Chapter 3 the damaging behaviour of 576 pigs from the experiment in Chapter 2 was evaluated. At 15, 18, and 24 weeks of age, prevalence of tail and ear damage, and of tail and ear wounds was scored. At 20 and 23 weeks of age, frequencies of biting behaviour and aggression were scored by behaviour sampling. The prevalence of ear damage during the finisher phase and the frequency of ear biting were increased in LSC compared with HSC pigs. The frequency of ear biting was increased in low protein fed pigs compared with normal protein fed pigs. The supplemented AA profile reduced ear biting only in LSC pigs. The prevalence of tail wounds was lower for pigs in LSC than for pigs in HSC in the grower phase. Regardless of dietary amino acid profile or sanitary status, pigs fed low protein diets showed more ear biting, tail biting, belly nosing, other oral manipulation directed at pen mates, and aggression than pigs fed normal protein diets, with no effect on ear or tail damage. In conclusion, both LSC and a reduction of dietary protein increased the occurrence of damaging behaviours in pigs and therefore may negatively impact pig welfare.

    The experiment of Chapter 4 was designed to quantify the difference in energy requirements for maintenance, and in incremental efficiencies for deposition of dietary energy and protein in the body of clinically healthy pigs kept under LSC or HSC, fed a basal diet either or not supplemented with additional methionine, threonine and tryptophan.

    In a 2 × 2 factorial arrangement, 24 groups of 6 pigs each were allocated to either a LSC or HSC, and were offered two different diets having either a basal or a dietary amino acid profile supplemented with methionine, threonine, and tryptophan. For each group of pigs, complete energy and nitrogen balances were determined during two consecutive weeks, during which feed was available ad libitum or at 70% of ad libitum. Fasting heat production was determined over a 25 h period of fasting after a period of restricted feeding. Low sanitary conditions increased fasting heat production from 696 to 750 kJ/(kg BW0.6 . d), regardless of the dietary amino acid supplementation. The incremental efficiency of ingested nitrogen for retention in the body was reduced in LSC pigs from 73 to 53%, but incremental efficiencies of digestible energy intake for fat deposition in the body were unaffected by the experimental treatments. These findings showed that the effects of continuous immune stimulation by introducing LSC, was affecting energy and nutrient efficiencies of pigs both at maintenance level and at a feeding level close to ad libitum intake.

    In Chapter 5 diurnal patterns for heat production, respiratory quotient, and carbohydrate and fat oxidation of the pigs studied in the experiment of Chapter 4 were evaluated to get more insight in the mechanisms behind the effects found in Chapter 4. The LSC pigs had reduced activity compared with HSC and a higher resting metabolic rate during the period of restricted feeding, especially during the light parts of the day. Therefore the diurnal energy expenditure pattern of LSC and HSC pigs can be considered as different. Fat and carbohydrate oxidation patterns were not different for LSC and HSC pigs, indicating that protein and fat deposition during the day was similar for LSC and HSC pigs.

    Overall, the results of this thesis indicate that both energy and AA requirements are greater in LSC pigs compared with HSC pigs. It is questionable, however, whether it is nutrient and cost effective and biologically possible to satisfy these increased nutrient requirements in LSC pigs, as the incremental efficiency of N for retained protein is low, and ADFI is reduced for LSC pigs compared with HSC pigs. The present thesis demonstrates that care should be taken in reducing dietary protein concentrations to improve protein efficiency in pigs, as it incurs a risk to increased damaging behaviours, particularly when pigs are kept under LSC.

    High-throughput sequencing of African chikanda cake highlights conservation challenges in orchids
    Veldman, Sarina ; Gravendeel, Barbara ; Otieno, Joseph N. ; Lammers, Youri ; Duijm, Elza ; Nieman, Aline ; Bytebier, Benny ; Ngugi, Grace ; Martos, Florent ; Andel, Tinde R. van; Boer, Hugo J. de - \ 2017
    Biodiversity and Conservation 26 (2017)9. - ISSN 0960-3115 - p. 2029 - 2046.
    CITES - Disa - Ethnobotany - Habenaria - Ion-Torrent PGM - Satyrium - Wildlife forensics
    Chikanda is a traditional dish made with wild-harvested ground orchid tubers belonging to three orchidioid genera, Disa, Satyrium and Habenaria, all of which are CITES appendix II-listed. Identification of collected orchid tubers is very difficult and documentation of constituent species in prepared chikanda has hitherto been impossible. Here amplicon metabarcoding was used in samples of six prepared chikanda cakes to study genetic sequence diversity and species diversity in this product. Molecular operational taxonomic unit identification using similarity-matching reveals that species of all three genera were present in the chikanda samples studied. Disa was present in all of the samples, Satyrium in five out of six and Habenaria in one of the samples, as well as a number of other plants. The fact that each sample contained orchids and the presence of a wide variety of species from all genera in this traditional dish raise serious concerns about the sustainability of this trade and the future of wild orchid populations in the main harvest areas. This proof-of-concept study shows that Ion-Torrent PGM is a cost-effective scalable platform for metabarcoding using the relatively long nrITS1 and nrITS2 regions. Furthermore, nrITS metabarcoding can be successfully used for the detection of specific ingredients in a highly-processed food product at genus level, and this makes it a useful tool in the detection of possible conservation issues arising from commercialized trade or processed plant products.
    Splicing-related genes are alternatively spliced upon changes in ambient temperatures in plants
    Verhage, D.S.L. ; Severing, Edouard ; Bucher, J. ; Lammers, M. ; Busscher-Lange, J. ; Bonnema, A.B. ; Rodenburg, Nicole ; Proveniers, Marcel C.G. ; Angenent, G.C. ; Immink, G.H. - \ 2017
    PLoS ONE 12 (2017)3. - ISSN 1932-6203
    Plants adjust their development and architecture to small variations in ambient temperature. In a time in which temperatures are rising world-wide, the mechanism by which plants are able to sense temperature fluctuations and adapt to it, is becoming of special interest. By performing RNA-sequencing on two Arabidopsis accession and one Brassica species exposed to temperature alterations, we showed that alternative splicing is an important
    mechanism in ambient temperature sensing and adaptation. We found that amongst the differentially alternatively spliced genes, splicing related genes are enriched, suggesting that the splicing machinery itself is targeted for alternative splicing when temperature changes. Moreover, we showed that many different components of the splicing machinery are targeted for ambient temperature regulated alternative splicing. Mutant analysis of a splicing related gene that was differentially spliced in two of the genotypes showed an altered flowering
    time response to different temperatures. We propose a two-step mechanism where temperature directly influences alternative splicing of the splicing machinery genes, followed by a second step where the altered splicing machinery affects splicing of downstream genes involved in the adaptation to altered temperatures.
    Notitie ‘Verdeling van beschikbare N uit drijfmest over het seizoen op grasland’
    Schroder, J.J. ; Curth-van Middelkoop, J.C. - \ 2016
    Wageningen UR Livestock Research, Commissie Bemesting Grasland en Voedergewassen - 8
    Ongeveer de helft van de stikstof (N) in rundveedrijfmest is organisch gebonden. Voor varkensdrijfmest is dat ongeveer een derde (Den Boer et al., 2012). Deze organisch gebonden N moet worden afgebroken (‘mineraliseren’) om door gewassen te kunnen worden opgenomen. Volledige afbraak kan tientallen jaren kosten. Bij een langdurig voortgezet gebruik van eenzelfde hoeveelheid organische mest-N komen de jaarlijkse aanvoer en de geaccumuleerde ‘staartjes’ afbraak met elkaar in evenwicht. Omstandig bewijs hiervoor kan gevonden worden in het feit dat de hoeveelheden organische stof in Nederlandse landbouwbodems niet lijken te stijgen (Reijneveld et al., 2009). Sluijsmans & Kolenbrander (1976) namen op basis van laboratoriumproeven met verdund zwavelzuur aan dat de helft van de organisch gebonden N in rundveedrijfmest al gedurende het eerste jaar na het moment van toediening mineraliseert (‘Ne’) en de andere helft (‘Nr’) in de (vele) jaren daarna. Overeenkomstige waarden voor varkensdrijfmest bedragen tweederde (‘Ne’) en één derde (‘Nr’). Op zichzelf is het begrijpelijk dat de mest van een met ruwvoer gevoede meermagige lastiger afbreekbaar is dan die van een éénmagige. Op basis van deze uitgangspunten berekende Lammers (1983) de eerstejaars N-werking van, onder meer, rundveedrijfmest en varkensdrijfmest.
    Selection for or against feather pecking: what are the consequences?
    Eijk, J.A.J. van der; Lammers, A. ; Kemp, B. ; Naguib, M. ; Rodenburg, T.B. - \ 2016
    In: 16th International Conference on Production Diseases in Farm Animals. - Wageningen, The Netherlands : Wageningen Academic Publishers - ISBN 9789086862856 - p. 176 - 176.
    Early-life behavioural development of lines divergently selected on feather pecking behaviour
    Eijk, J.A.J. van der; Lammers, A. ; Kemp, B. ; Naguib, M. ; Rodenburg, T.B. - \ 2016
    In: Proceedings of the 50th Congress of the International Society for Applied Ethology. - Wageningen, The Netherlands : Wageningen Academic Publishers - ISBN 9789086862870 - p. 85 - 85.
    The behavioural development of an animal is affected by the interplay between its genetic background and its environment. In laying hens, feather pecking is a damaging behaviour that involves pecking and pulling at the feathers or tissue of conspecifics, negatively affecting welfare. Feather pecking is a heritable trait, but its development can be affected by manyfactors, including environmental factors. In order to better understand the development of this damaging behaviour, we characterised the early-life behavioural development of lines selected both for and against feather pecking. We used genetic lines selected for high (HFP)and low (LFP) feather pecking and an unselected control line. Lines were housed separately in groups of 19 birds per pen, with 8 pens per line. Group size was reduced by 2-3 birds at0, 5 and 10 weeks of age. There were two batches that differed two weeks in age. Birds were tested at 0 and 10 weeks of age in a novel object test, at 4 weeks of age in a novel environment test and at 15 weeks of age in an open field test. Data were analysed using mixed models, with selection line as fixed factor and pen nested within batch as random factor. When data were not normally distributed the non-parametric Kruskal Wallis test was used. HFP birds had a shorter latency to approach the novel object compared to LFP and control birds at both 0 weeksof age (HFP=36 s, LFP=120 s and control=117.5 s, F2,20=36.52, P<0.0001) and 10 weeks ofage (HFP=16.88 s, LFP=79.75 s and control=61 s, F2,20=12.60, P=0.0003). Furthermore, HFP birds had a shorter latency to vocalize compared to LFP and control birds at both 4 weeks of age (HFP=5.48 s, LFP=15.16 s and control=16.2 s, X22=42.23, P<0.0001) and 15 weeks of age(HFP=26.34 s, LFP=50.27 s and control=37.63 s, X22=15.59, P=0.0004). Thus, based on these three tests, HFP birds were less fearful at all studied ages compared to control and LFP birds. In addition, HFP birds showed a more pro-active coping style than control and LFP birds. In conclusion, our results suggest that selection for feather pecking affects early-life behavioural characteristics. These results can help to better understand the development of feather pecking behaviour, and possibly to identify early-life behavioural characteristics as potential indicators of feather pecking.
    Divergent selection on feather pecking affects natural antibody levels
    Eijk, J.A.J. van der; Lammers, A. ; Kemp, B. ; Naguib, M. ; Rodenburg, T.B. - \ 2016
    In: Proceedings of the Benelux ISAE Conference 2016, Proceedings of the Benelux ISAE Conference 2016 Berlicum, The Netherlands : International Society for Applied Ethology (ISAE) - ISBN 9789462573949 - p. 23 - 23.
    Do feather pecking hens go with their guts?
    Eijk, J.A.J. van der; Vries, H.J.A. de; Naguib, M. ; Kemp, B. ; Smidt, H. ; Rodenburg, T.B. ; Lammers, A. - \ 2016
    In: Abstracts of lectures and posters Mind, Mood & Microbes Conference 2016. - Amsterdam : - p. 69 - 69.
    Do feather pecking hens go with their guts?
    Eijk, J.A.J. van der; Vries, H.J.A. de; Naguib, M. ; Kemp, B. ; Smidt, H. ; Rodenburg, T.B. ; Lammers, A. - \ 2016
    Does a reduction in dietary protein affect immune status of pigs kept under different sanitary conditions?
    Meer, Y. van der; Gerrits, W.J.J. ; Jansman, A.J.M. ; Kemp, B. ; Lammers, A. - \ 2016
    In: Energy and protein metabolism and nutrition. - Wageningen Academic Publishers (EAAP publication 137) - ISBN 9789086862863 - p. 163 - 164.
    Performance of pigs kept under different sanitary conditions affected by protein intake and amino acid supplementation
    Meer, Y. van der; Lammers, A. ; Jansman, A.J.M. ; Rijnen, M.M.J.A. ; Hendriks, W.H. ; Gerrits, W.J.J. - \ 2016
    Journal of Animal Science 94 (2016)11. - ISSN 0021-8812 - p. 4704 - 4719.
    Amino acid - Immune system - Performance - Pig - Protein - Sanitary conditions

    There is growing evidence that requirements for particular AA increase when pigs are kept under low sanitary conditions. The extent towhich reduction in growth performance is related to these increased requirements is unclear. To evaluate this relationship, an experiment (2 × 2 × 2 factorial arrangement) was performed with 612 male pigs (9 per pen) kept under low sanitary conditions (LSC) or high sanitary conditions (HSC) and offered ad libitum access to either a normal CP concentration diet (NP; 17, 15, and 15% CP for the starter, grower, and finisher phase, respectively) or a low CP concentration diet (LP; 20% CP reduced relative to NP for each phase), each of which containing a basal AA profile (AA-B) or a supplemented AA profile (AA-S). The supplemented diet type contained 20% more Met, Thr, and Trp relative to Lys on an apparent ileal digestible basis compared with the basal diet type. Pigs were followed for a complete fattening period and slaughtered at a targeted pen weight of 110 kg. Haptoglobin concentrations in serum (0.92 g/L for LSC and 0.78 g/L for HSC) and IgG antibody titers against keyhole limpet hemocyanin (3.53 for LSC and 3.08 for HSC) collected in the starter, grower, and finisher phases and pleuritis scores at slaughter (0.51 for LSC and 0.20 for HSC) were greater for LSC pigs compared with HSC pigs (P ≤ 0.01), illustrating that sanitary conditions affected health conditions. The ADG and G:F were greater for HSC pigs compared with LSC pigs (P ≤ 0.01). The number of white blood cells (WBC) was higher in (AA-S)–fed pigs compared with (AA-B)–fed pigs when kept at LSC but not at HSC [SS (sanitary conditions) × AA interaction, P = 0.04]. Pigs fed NP had a lower number of WBC compared with pigs fed LP (P = 0.02). The number of platelets in pigs fed AA-S diets was higher compared with pigs fed AA-B diets (P ≤ 0.01). A 20% reduction in dietary supplementation of Met, Thr, and Trp relative to Lys decreased G:F more in LSC pigs than in HSC pigs (interaction, P = 0.03), illustrating that dietary requirements for these AA differ depending on sanitary conditions. This study, performed under practical conditions, shows that AA requirements are dependent on sanitary conditions. Furthermore, supplementation of diets with particular AA may improve performance, especially under poor hygienic conditions. Dietary protein concentration as well as Met, Thr, and Trp supplementation can modify immune status, which may influence resistance to sub-clinical and clinical diseases.

    Intestinal immune maturation is accompanied by temporal changes in the composition of the microbiota
    Hartog, C.G. den; Vries Reilingh, G. de; Wehrmaker, A.M. ; Savelkoul, H.F.J. ; Parmentier, H.K. ; Lammers, A. - \ 2016
    Beneficial Microbes 7 (2016)5. - ISSN 1876-2883 - p. 677 - 685.
    IgA - development - homeosta - intestine - oponisation of bacteria
    In animals establishment of the intestinal microbial ecosystem is influenced by mucosal immune functions. As mucosal immune functions dynamically change during development of juvenile layer chicken, this study focused on dynamics in the ileal microbiota composition in relation to intestinal immune development. In addition, the levels of immunoglobulin (Ig) in serum and amount of bacteria coated with IgA, a hallmark of intestinal immune maturation, were analysed. The composition of the intestinal microbiota transiently changed at the age of 14-42 days compared to the microbiota composition before and after this period. This temporal deviation in microbiota composition was associated to a temporal increase in transcriptional activity of pro-inflammatory cytokine genes. Furthermore, before week two limited amounts of faecal bacteria were bound by IgM and from week two increasing amounts of bacteria were bound by IgA, reaching a maximal level of 70% of IgA-coated bacteria at 6 weeks of age. These data could indicate that prior to achievement of intestinal homeostasis at 6-10 weeks post hatch, activation of inflammatory pathways cause a temporal disturbance of the microbiota composition. This period of imbalance may be essential for adequate immune development and establishment of intestinal homeostasis.
    Does dietary protein reduction affect immune status of pigs kept under different sanitary conditions?
    Meer, Y. van der; Gerrits, W.J.J. ; Jansman, A.J.M. ; Kemp, B. ; Lammers, A. - \ 2016
    EAAP publication 137
    Do feather pecking hens go with their guts?
    Eijk, J.A.J. van der; Lammers, A. ; Kemp, B. ; Naguib, M. ; Rodenburg, T.B. - \ 2016
    Effects of early life dextran sulfate sodium administration on pathology and immune response in broilers and layers
    Simon, K. ; Arts, J.A.J. ; Vries Reilingh, G. De; Kemp, B. ; Lammers, A. - \ 2016
    Poultry Science 95 (2016)7. - ISSN 0032-5791 - p. 1529 - 1542.
    Chicken - DSS - Immune response - Intestinal homeostasis

    Intestinal pathology early in life may affect immune development and therefore immune responses later in life. Dextran sulfate sodium (DSS) induces colitis in rodents and is a widely used model for inflammatory bowel diseases. The present study investigated DSS as a model for early life intestinal pathology and its consequences on intestinal pathology, ileal cytokine, and immunoglobulin mRNA expression levels as well as the antibody response towards an immunological challenge later in life in chickens. Broiler and layer chicks received 2.5% DSS in drinking water during d 11 through d 18 post hatch or plain drinking water as a control. As an immunological challenge all birds received a combination of Escherichia coli lipopolysaccharide (LPS) and human serum albumin (HuSA) intramuscularly (i.m.) at d 35, and antibody titers against LPS, HuSA, and keyhole limpet hemocyanin (KLH) were determined to investigate effects of intestinal inflammation early in life on humoral immunity later in life. DSS treated birds showed a decrease in BW from which broilers quickly recovered, but which persisted for several weeks in layers. Histological examination of intestinal samples showed symptoms similar to those in rodents, including shortening and loss of villi and crypts as well as damage of the epithelial cell layer of different parts of the intestine. Effects of DSS on intestinal morphology were less severe in broilers that also showed a lower mortality in response to DSS than layers. No effect of DSS on ileal cytokine expression levels could be observed, but ileal immunoglobulin expression levels were decreased in DSS treated broilers that also showed lower antibody titers against LPS in response to the challenge. In conclusion, DSS may serve as a model for intestinal pathology early in life, although more research on the appropriate dose is necessary and is likely to differ between breeds. Results from the present study could indicate that broilers are less susceptible to DSS compared with layers or have a better capacity to recover from intestinal pathology.

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