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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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    Consequences of dry period length and dietary energy source on physiological health variables in dairy cows and calves
    Mayasari, Nova - \ 2017
    Wageningen University. Promotor(en): B. Kemp, co-promotor(en): A.T.M. Knegsel; H.K. Parmentier. - Wageningen : Wageningen University - ISBN 9789463431408 - 221
    dairy cows - calves - dry period - feed rations - feeds - energy balance - animal health - inflammation - antibodies - adaptation physiology - immunology - melkkoeien - kalveren - gustperiode - voedingsrantsoenen - voer - energiebalans - diergezondheid - ontsteking - antilichamen - adaptatiefysiologie - immunologie

    During the transition period, dairy cows experience a negative energy balance (NEB) caused by the high energy requirement for milk yield, while feed intake is limited. Severity of the NEB has been associated with an increased incidence of metabolic disorders and infectious diseases, inflammation, immunosuppression and oxidative stress. It is known that shortening or omitting the dry period or feeding a glucogenic ration improves the energy balance (EB) in dairy cows in early lactation. It can be expected that an improvement of the EB due to shortening or omitting the dry period results in reduced inflammation, immunosuppression and less oxidative stress in dairy cows in early lactation. The first objective of this thesis was to study the effects of dry period length and dietary energy source on immune competence, inflammatory biomarkers and oxidative stress in dairy cows over 2 subsequent lactations. The second objective was to study the consequences of maternal dry period length on colostrum immunoglobulin content and immune competence of calves in the first 12 weeks of life. In the current study, 167 cows were assigned to 3 dry period lengths (0, 30, or 60 d) and 2 early lactation rations (glucogenic or lipogenic). Cows were planned to have the same dry period length and ration over 2 subsequent lactations. Omitting the dry period reduced plasma bilirubin levels compared with a conventional dry period, which is line with the better EB in cows with a 0-d dry period. Effects of dry period length on inflammatory biomarkers, oxidative stress variables and natural antibodies (NAb) titers were, however, less consistent. Omitting the dry period increased not only negative acute phase proteins (APP) in plasma, but also positive APP, oxidative stress variables in plasma, and NAb in milk. Shortening the dry period to 30-d did not influence inflammatory biomarkers and oxidative stress compared with a conventional dry period of 60-d. Occurrence of clinical health problems did not differ between cows with different dry period lengths. In the current study, changes in positive APP and oxidative stress variables in plasma and NAb in milk could be explained by the occurrence of clinical health problems related to inflammation (clinical mastitis, fever, metritis and retained placenta), rather than a better EB due to a shorter or no dry period. Moreover, a higher titer of IgG binding lipopolysaccharide in plasma was associated with decreased odds of high somatic cell count and occurrence of clinical mastitis. In the first lactation after implementation of dry period length and dietary treatments, feeding a glucogenic ration in early lactation increased NAb titers in milk compared with a lipogenic ration, which could be explained partly by a better EB. In the second lactation after implementation of dry period length and dietary treatments, feeding a lipogenic ration in early lactation increased cholesterol levels in plasma compared with a glucogenic ration, which could be related to the high fat content in this ration. Cows with a 0-d dry period had a lower colostrum production and less immunoglobulins in colostrum compared with cows with a 30-d or 60-d dry period. After colostrum uptake, NAb titers in plasma of calves from cows with a 0-d dry period were lower during the first week of life compared with calves from cows with a 30-d or 60-d dry period. Levels of specific antibodies in calves, after immunization in week 6 and 10, in calves were not affected by the maternal dry period length. Birth weight of calves from cows with a 0-d dry period was lower compared with calves from cows with a 30-d dry period, but not compared with calves from cows with a 60-d dry period. Growth of calves until 12 weeks of life was not affected by dry period length. In conclusion, although shortening and omitting the dry period improved the EB in early lactation, this did not result in clear consistent effects of dry period length on inflammation or oxidative stress. Changes in inflammation biomarkers, oxidative stress variables and NAb in milk were a reflection of the occurrence of health problems related to inflammation in particular clinical mastitis and compromised uterine health. Furthermore, albeit omitting the dry period compared with shortening or conventional dry period cows resulted in a reduced immunoglobulin content in colostrum and reduced NAb titers in plasma of their calves in the first week of life, but did not affect specific immune response of the calves in the first 12 weeks of life.

    Physiological and molecular adaptations of Lactococcus lactis to near-zero growth conditions
    Ercan, O. - \ 2014
    Wageningen University. Promotor(en): Michiel Kleerebezem, co-promotor(en): Eddy Smid. - Wageningen : Wageningen University - ISBN 9789462570719 - 206
    lactococcus lactis - adaptatiefysiologie - voedselmicrobiologie - groeitempo - groeispanning - transcriptomica - metabolomica - lactococcus lactis - adaptation physiology - food microbiology - growth rate - growth stress - transcriptomics - metabolomics

    Lactococcus lactis is an important lactic acid bacteria (LAB) species that is used for the manufacture of dairy products, such as cheese, buttermilk, and other fermented products. The predominant function of this bacterium in dairy fermentation is the production of lactic acid, as its major fermentation end-product that contributes to preservation and microbial safety of the product. Moreover, L. lactis is frequently encountered in natural ecosystems such as in (rotting) plant material.

    Due to restricted energy source availability, natural microbial communities commonly live in a situation that can be characterized as ‘hunger’, which is different from strict nutrient-starvation. As a consequence, environmental microbes commonly grow at very low-growth rates as compared to laboratory cultures. Analogously, microorganisms can experience such nutrient-poor conditions in diverse industrial fermentation applications. For example, LAB encounter extreme low or no energy source availability during the extended ripening process of cheeses or dry sausages, which can take months. Despite these harsh environmental conditions, many LAB are able to remain viable in these processes for months and sustain a low-level metabolic activity, which plays an important role in their contribution to flavor and aroma formation in the product matrix.

    In this thesis, the quantitative physiology of L. lactis at near-zero specific growth rates was studies, employing both metabolic and genome-wide transcriptome studies in an experimental set-up of carbon-limited retentostat cultivation. Chapter 2 describes how retentostat cultivation enables uncoupling of growth and non-growth related processes in L. lactis, allowing the quantitative analysis of the physiological adaptations of this bacterium to near-zero growth rates. In chapter 3, transcriptome and metabolome analyses were integrated to understand the molecular adaptation of L. lactis to near-zero specific growth rate, and expand the studies in chapter 2 towards gene regulations patterns that play a profound role in zero-growth adaptation. Chapter 4 describes the enhanced robustness to several stress conditions of L. lactis after its adaptation to extremely low-specific growth rate by carbon-limited retentostat cultivation. In this chapter correlations were modelled that quantitatively and accurately describe the relationships between growth-rate, stress-robustness, and stress-gene expression levels, revealing correlation coefficients for each of the varieties involved. Chapter 5 evaluates the distinction between the transcriptome responses to extended carbon-limited growth and severe starvation conditions, where the latter condition was elicited by switching off the medium supply of the retentostat cultures described in chapter 1. Chapter 6 highlights the comparison of the physiological and molecular adaptations of industrially important microorganisms towards carbon-limited retentostat conditions. In conclusion, this thesis describes the quantitative physiological, metabolic, and genome-wide transcriptional adaptations of L. lactis at near-zero specific growth rates induced by carbon source limited retentostat cultivation, and compares these molecular adaptations to those elicited by strict carbon-starvation conditions.

    Metabolic adaptation of white adipose tissue to nutritional and environmental challenges
    Hoevenaars, F.P.M. - \ 2014
    Wageningen University. Promotor(en): Jaap Keijer, co-promotor(en): Evert van Schothorst. - Wageningen : Wageningen University - ISBN 9789461739162 - 166
    muizen - vetweefsel - metabolisme - adaptatiefysiologie - voeding - milieufactoren - obesitas - energieopname - zuurstoftekort - ontsteking - voedingsfysiologie - diermodellen - mice - adipose tissue - metabolism - adaptation physiology - nutrition - environmental factors - obesity - energy intake - oxygen deficiency - inflammation - nutrition physiology - animal models

    Summary of main findings

    When adipose tissue is present in excessive amounts, as in obesity, it predisposes to a number of pathologies. Obesity is a complex, multifactorial condition as it influences many endogenous genetic, endocrine, and inflammatory pathways. Excess dietary intake is one of the important factors which are responsible for the increasing prevalence of obesity. For the understanding of the reciprocity between

    consumed diet and excessive amounts of adipose tissue, it is essential to investigate underlying functioning. In this thesis, I have addressed three important aspects that play a role in the development of diet induced obesity and its pathologies with a focus on adipose tissue metabolism.

    Does a body weight set-point exist?

    How is the diet-induced metabolic response affected by housing at


    Does oxygen restriction induce inflammation in white adipose tissue?

    The first aspect investigated was the existence of a body weight set point. A body weight set point is defined as a pre-determined or preferred level of body weight which is preserved by an internal feedback control mechanism. In chapter 2, a dietary intervention with none, one, or two diet alterations of purified diets was performed in C57BL/6J mice to investigate if a long lasting effect on body weight persistence was present. Diets contained equal protein content and source of ingredients but differed in the fat-to-sugar ratio. Therefore, energy content and amount of fat was different for either the low fat diet or the high fat. In the intervention the last consumed diet of the mice determined energy intake, energy expenditure, body weight, body fat stores, circulating hormones and metabolites. These data support the settling point theory as body weight and metabolic parameters ‘settle’ based on current energetic input and output and do not support the set point theory. Next to that it underlines the importance of diet choice in intervention studies focusing on aspects on the crossroads of nutrition and physiology.

    In chapter 3adipose tissue physiology and molecular regulation was further investigated by exposure to more metabolic stress in the form of a weight loss challenge with different purified diets. Diet-induced obese C57BL/6J mice were fed a high fat diet restricted to 70% intake of previous ad libitum high fat diet

    intake or they were changed to ad libitum low fat diet for 5 weeks. Beneficial effects were seen in both interventions regarding physiological parameters. However, molecular parameters in white adipose tissue differed between the two restriction interventions, with increased activation of mitochondrial carbohydrate and fat metabolism in high fat diet restricted mice. When extrapolated to the human

    situation this may suggest that a reduction of portion size is the best method for weight loss.

    It is standard practice to house mice at ambient temperature during physiological intervention studies. Unfortunately mice are then exposed to a temperature below their thermal neutral zone. This implies that their metabolism is chronically increased which is known to influence study outcomes. In chapter 4the second question; “how is the diet-induced metabolic response affected by housing at thermoneutrality?”was investigated. A 14-week dietary intervention with two semi-purified diets, a

    low fat diet and a moderately high fat diet, was performed at 28°C in C57BL/6J mice. This resulted in a large diet-induced difference in bodyweight, adipose tissue mass, adipocyte size, and serum leptin level. But no differential effects of the diets were seen on serum glucose, free fatty acids, triacylglycerides, insulin, a panel of cardiovascular markers, and a number of (metabolic) parameters in liver and muscle.

    Although adipose tissue mass and adipocyte size was increased significantly, there was no sign of inflammation or dysfunction in the adipose tissue. This study suggests that diet-induced obesity of C57BL/6J mice at thermoneutrality results in a suitable model for the metabolically ‘healthy’ obese (people who are significantly overweight but show none of the usual metabolic problems). Next to that, this study emphasizes the importance of consideration and control of housing temperature for mice, as it has profound effects on study outcomes.

    The third and last question investigated was if oxygen restriction is able to induce inflammation in white adipose tissue. There is substantial evidence that white adipose tissue becomes hypoxic when excessively enlarged. Due to fast expansion of white adipose tissue the vasculature is not able to keep pace with growth. Next to that, adipocytes are able to increase in size beyond the limit of oxygen diffusion. To investigate if hypoxia was able to induce inflammation in white adipose tissue, the model for healthy obese adipocytes (developed in chapter 4) was used and exposed to ambient oxygen restriction (13%) to challenge adipose tissue metabolism. This resulted in the presence of systemic oxygen restriction as shown by increased levels of hemoglobin and hematocrit. Furthermore a switch to glycolytic metabolism, which is indicative for tissue hypoxia, was present. No differences in adipose tissue macrophage infiltration (as marker for inflammation) were found. But, serum branched chain amino acids and adipokines were affected. Branched chain amino acids were increased in mice exposed to oxygen restriction which shows resemblance with findings in humans where increased levels were found in lean versus obese people. The peptide hormone adiponectin was increased in serum, without differences in WAT expression. On the other hand, the peptide hormones CCDC3 and CCK showed decreased transcript levels in white adipose tissue without significant change in serum levels, although for CCDC3 a trend was seen. Together these results suggest that oxygen restriction does not induce inflammation in adipose tissue. However, it does affect adipokine regulation.

    After performing these studies it was clear that composition of the diet has a major influence on outcome parameters of physiological studies as shown in chapter 2. To compare functional effects of different nutrients, it is important to use standardized purified diets. Not only the experimental intervention diet is of importance but also the reference control diet can influence outcomes. For example, when an intervention is performed with a high fat purified diet and the reference diet is chow this will lead to a difficult comparison. The content of chow is variable as it is grain or cereal based (ground corn, ground oats alfalfa meal, soybean meal and ground wheat). Nutritional adequacy is ensured by addition of vitamins, minerals, and fat. However, the exact amount of the various ingredients is frequently kept secret by the manufacturer. Next to that, due to the plant based origin of chow it will contain nutritive (protein, carbohydrate, fat) components but also non-nutritive components (phytochemicals). The content of the chow diet will vary from batch to batch as the nutritive and nonnutritive value will change between harvests. When using a chow reference diet in

    comparison to a purified diet you will never know exactly what you are comparing, i.e. difference in amino acids or effects of phytochemicals etc. Therefore, a reference diet for physiology was designed (chapter 6) to improve comparison of study outcomes and to increase efficiency of resources and material. A key feature of the diet is the fixed protein concentration, which allows for an exchange of carbohydrate and fat in a high fat version of the diet.

    To conclude, the work presented in this thesis provides clear insight in factors that are of importance for improvement of translatability of mouse studies to the human situation. It was shown that when investigating the weight balance many parameters, i.e. genetics, metabolic rate, environmental factors like ambient housing temperature and light and cognitive behavior, besides the diet and its composition are able to influence the outcome parameters. As most mouse experiments are performed

    in a fixed environment with no choices of food and a standard temperature set to 22°C. This is clearly not reflective of humans under free living conditions. However, these fixed conditions are able to result in experiments that unravel underlying mechanisms of weight balance, which form the basis for discovering a solution to the obesity epidemic.

    Living on the edge: physiological and behavioural plasticity of African antelopes along a climatic gradient
    Shrestha, A.K. - \ 2012
    Wageningen University. Promotor(en): Herbert Prins; Steven Bie, co-promotor(en): Sip van Wieren. - S.l. : s.n. - ISBN 9789461733856 - 135
    antilopen - taurotragus oryx - connochaetes taurinus - aepyceros melampus - klimaatverandering - microklimaat - diergedrag - thermoregulatie - microhabitats - warmtestress - adaptatiefysiologie - antelopes - taurotragus oryx - connochaetes taurinus - aepyceros melampus - climatic change - microclimate - animal behaviour - thermoregulation - microhabitats - heat stress - adaptation physiology

    Climate change, habitat loss and fragmentation individually or synergistically force species to
    live in a sub-optimal condition in terms of climate and resource posing threat to fitness and
    survival of the species. Hence, a very pressing issue for biodiversity conservation at present is
    to understand if species are able to keep pace with these rapidly changing environment
    conditions. To persist with these changes, phenotypic plasticity of behaviour and physiology
    may be the most likely response for long-lived endothermic species because of their longer
    generation times. Therefore, the central aim of this thesis is to investigate intra- and intervariability
    of behavioural and physiological adaptation of range of African antelopes along
    spatio-temporal scales in their natural habitats.
    With the aim to understand the behavioural plasticity of African antelopes to the climatic
    stress, in Chapter 2, I investigated effect of heat stress on diurnal activity pattern of three
    species of antelopes of different body size and feeding types namely, eland Taurotragus oryx
    (≈ 420 kg; mixed feeders), blue wildebeest Connochaetes taurinus (≈180 kg; grazer) and
    impala Aepycerus melampus (≈ 50 kg; mixed feeder) across season and extreme climatic
    condition as indicated by the 10 hottest days. During summer when the heat stress was its
    highest, the heat stress negatively influenced diurnal activity of all the three species.
    However, they shifted the timing of their activity more to the early morning (eland) or late in
    the evening, or both (wildebeest and impala) to avoid heat stress and maximize intake of food
    in a season when forage is abundant. During the spring and the 10 hottest days over the entire
    study period, only the diurnal activity of the larger antelopes (eland and wildebeest) was
    negatively influenced by the heat stress whereas the smaller impala was unaffected.
    Therefore, these large African antelopes apparently suffer from heat stress during spring and
    the extreme hottest days due to their limited capacity to dissipate heat.
    In chapter 3, to understand possible behavioural adaptation of the largest African antelope
    eland against the thermal stress, I investigated the daily and seasonal selection of
    microhabitats based on altitude and microclimate at the southern limits of its distributional
    range. Eland actively selected lower altitudes with warm microclimates during the winter and
    the five coldest days when the ambient conditions were below its thermal neutral zone. In
    contrast, eland did not select higher altitudes or cooler climate when it was warm in the
    summer. However, selection of cooler microhabitats was only evident in the three extremely
    hottest days when the heat stress was close to the upper end of its thermal neutral zone.
    Hence, the eland was able to use diverse topography as a thermal refuge to buffer the adverse
    effect of both cold and very hot condition.
    In the fourth chapter, to study behavioural response of African antelopes to variation in food
    resources which is predicted to exacerbate due to climate change and habitat loss and
    fragmentation, I investigated adaptation of home range sizes of eland, impala (both mixed
    feeders) and wildebeest (a grazer) over time (seasons) and between two climatically
    contrasting areas in South Africa, taking Mapungubwe National Park as the core area and
    Asante Sana Game Reserve as the edge area. This comparative study not only showed the
    home range size of wildebeest in Mapungubwe was larger during the resource-poor dry
    season compared to the resource-rich wet season but their home range size in the core area
    was also a four to seven times larger in the dry season than those in the edge area. In contrast,
    the home range size of impala was 3-14 times larger in the edge area than those in the core
    area. Surprisingly, the home range size of eland neither differs across any season within study
    areas nor between Asante Sana and Mapungubwe, while their average year-round home
    range size in core area was larger than that in edge area. These results suggest that the home
    range size of these African antelope is most likely a response to resource quality and
    availability specific to the local habitat.
    With an attempt to investigate physiological plasticity of African antelopes over a spatiotemporal
    context, in Chapter 5, I compared intraspecific variation of body temperature, as
    measured by amplitude, of the eland, blue wildebeest and impala in the two climatically
    contrasting areas: one with a less seasonal pattern and a mild winter (Mapungubwe National
    Park) and the other with a more seasonal pattern and a long and cold winter (Asante Sana
    Game Reserve). The 24-hour amplitude of body temperature of both mixed feeder (eland and
    impala) did not differ between the study sites, regardless of season. In contrast, the grazer
    (wildebeest) at a less seasonal site exhibited not only a higher variability in the 24-hour
    amplitude of body temperature (Tb)(~4ºC) but also a lower daily minimum body temperature
    by ~2 ºC compare to the normothermic level during the dry season than the wildebeest at a
    seasonal site. Further, the variation in Tb amplitude were influenced both by temperature
    (positive effect) and rainfall (negative effect), a proxy for food availability only among the
    wildebeest from less seasonal site. This suggest that these physiological response of higher
    variability of Tb amplitude and reduced minimum Tb among the wildebeest in Mapungubwe
    is a response to nutritional stress rather than a response to cold climate.
    These behavioural (home range) and physiological (body temperature) response of African
    antelopes to stressful conditions are specific for species and habitats. The smallest impala,
    which is a mixed feeder, maintained homeothermy even though they were exposed to
    stressful habitats by selecting the most productive habitat, i.e., riparian habitat in
    Mapungubwe. In Asante Sana, impala maintained homeothermic status by extending their
    dry season home range size when their principle food Acacia Karoo was not available. The
    largest antelope (eland) maintained homeostasis by ranging over large areas to track
    heterogeneously distributed resources, which is only possible due to their large size and
    ability to cope with lower quality food. Eland in Mapungubwe had larger home range sizes
    compared to Asante Sana which was most probably due to the poor quality of the habitat in
    Mapungubwe. Interestingly, the wildebeest in Mapungubwe did not maintain homeothermy
    particularly in dry season. Not only their amplitude of Tb was much larger (~4ºC) and
    Minimum Tb lowered by 2 ºC compared to normothermic level, they also extended their
    home range size four to seven folds compared to the wildebeest in Asante Sana. This failure
    to maintain homeothermy and extension of home range size was due to nutritional stress and
    therefore these antelopes are living in a physiologically stressful environment. With the
    predicted increase in the frequency and intensity of drought periods in southern Africa due to
    climate change, wildebeest, and other grazers, will likely experience greater nutritional stress
    in the future.
    To conclude, this thesis shows importance of studying behavioural and physiological traits
    among a range of species along temporal and spatial scales in their natural habitats to
    understand the adaptive capacity, therefore sensitivity of animal species. Apparently,
    homeothermic mammals cannot cope well with heat stress, which negatively influence the
    larger ones more than the smaller ones. However, mammals can overcome these stresses by
    shifting time of their activity to cooler parts of the day or by selecting optimal microhabitats
    that minimize absorption of heat at high temperatures or that maximize the absorption of heat
    at low temperatures. The behavioural (larger home range size) and physiological (reduced
    body temperature) response of wildebeest, a grazer to dry season but not that of the mixed
    feeder emphasizes that grazers will become more nutritionally stressed than mixed feeders at
    times of low rainfall. With the predicted increase in low rainfall events in many parts of the
    world and changes in vegetation structure in savannas due to climate change, browsers and
    mixed feeders will be likely to benefit more in future than the ruminant grazers.

    The second parity sow : causes and consequences of variation in reproductive performance
    Hoving, L.L. - \ 2012
    Wageningen University. Promotor(en): Bas Kemp, co-promotor(en): Nicoline Nieuwenhuizen-Soede. - S.l. : s.n. - ISBN 9789461731470 - 171
    varkens - zeugen - voortplanting - voortplantingsvermogen - adaptatiefysiologie - pigs - sows - reproduction - reproductive performance - adaptation physiology

    Many sows show reduced litter sizes in their second parity compared with their first parity. The aim of the current thesis was to describe causes and consequences of variation on second parity reproductive performance and to evaluate if feeding strategies during early gestation affect reproductive performance and sow body weight recovery after first lactation. In a first study, effects of sow weight development from first insemination up to first weaning on second parity reproductive performance were studied. Weight gain from first insemination up to first weaning showed a positive effect on non-pregnancy as well as on litter size, especially on a farm where gilts were relatively young and light at time of first insemination. In a second study, effects of weight loss during lactation were evaluated on embryonic survival and metabolic parameters during lactation and gestation in primiparous sows that were fed close to ad libitum. Sows with a high (>13.8%) weight loss showed a lower embryonic survival and fewer vital embryos at day 35 of gestation compared with sows with a lower weight loss, whilst no differences in metabolic parameters (IGF-1, NEFA, urea) were seen. The fact that the number of implantation sites was lower in high weight loss sows compared with low weight loss sows indicates that the negative effects of weight loss were already present during late lactation or early gestation. In a third study, a data-analysis using 46,500 sows was performed to assess relations between second parity performance and reproductive performance in later parities. Results showed that farrowing rate and litter size in parity 3 and up, as well as parity at culling, were related to second parity reproductive performance. These relations with second parity litter size were affected by first parity litter size. In practice, feed allowance during early gestation is often limited and might not be sufficient to support growth and recovery from lactation. The question was therefore raised if increased feed or protein intake during early pregnancy could improve litter size. In two experiments, the effects of an altered feeding strategy during the first month of gestation on farrowing rate and litter size (exp. 1) and embryonic survival and embryonic and placental development and metabolic parameters (exp. 2) were assessed. In Experiment 1, a 30% higher feeding level increased litter size with two piglets, without negatively affecting piglet birth weight. In Experiment 2, designed to find a physiological explanation for these results, an increased feeding level did not affect embryonic survival, embryonic development or placental development. Furthermore, no relations with metabolic parameters were found. From this thesis it can be concluded that second parity reproductive performance is related to reproductive performance in later parities. In order to improve second parity reproductive performance, weight loss during first lactation should be limited and gilts should be heavier at first weaning than at first insemination. Further, increased feeding levels during early gestation improve sow body weight recovery, without negatively affecting reproductive performance.

    Leren vreten als een varken
    Makkink, C.A. ; Oostindjer, M. ; Souza Da Silva, C. ; Bolhuis, J.E. - \ 2011
    De Molenaar 15 (2011). - ISSN 0165-4284 - p. 38 - 39.
    zeugen - varkenshouderij - biggen - adaptatiefysiologie - diervoedering - varkensvoeding - sows - pig farming - piglets - adaptation physiology - animal feeding - pig feeding
    Hoe leren biggen eten? Hun moeder speelt daarbij een cruciale rol. De verticale informatieoverdracht tussen zeug en biggen was het onderwerp waar Marijke Oostindjer cum laude op promoveerda aan Wageningen Universiteit
    Adaptive capacity of rearing hens : effects of early life conditions
    Walstra, I. - \ 2011
    Wageningen University. Promotor(en): Bas Kemp, co-promotor(en): Henry van den Brand; Jan ten Napel. - [S.l.] : S.n. - ISBN 9789461731265 - 147
    hennen - opfoktechnieken - broeden - uitbroeden - embryogenese - experimentele infectie - warmtestress - immuniteitsreactie - immunologie - adaptatiefysiologie - hens - rearing techniques - incubation - hatching - embryogenesis - experimental infection - heat stress - immune response - immunology - adaptation physiology

    The traditional strategy to deal with pathogens in the layer industry is based on monitoring and control methods, primarily aimed at minimizing the risk of infection with the pathogen. The aim of this thesis was to investigate whether the adaptive capacity of layers could be influenced by early life conditions as they may occur in layer practice, as an alternative strategy for improving layer health and disease resistance. The first study investigated whether suboptimal versus optimal incubation, hatch and early rearing conditions could influence the adaptive capacity during infectious challenges with Eimeria and Infectious Bronchitis (IB). The second study investigated effects of prenatal high temperature manipulation on postnatal temperature preference and adaptive response of layers to heat stress. The third study investigated effects of suboptimal and optimal incubation temperature on the adaptive response to Eimeria under normal circumstances or following exposure to a high (35oC) environmental temperature. The fourth study investigated effects of feed provision immediately after hatch (early feeding) and suppression of gram negative intestinal bacteria (by use of the antibiotic Colistin) for 21 d post hatch on microbial composition of the intestines, layer development and response to a mix challenge with lipopolysaccharide (LPS) and humane serum albumin (HuSA). Finally, effects of early feeding and Colistin treatment on organ weights and response to an infectious challenge with Eimeria were investigated. Results demonstrated that optimized incubation, hatch and rearing resulted in a better adaptive response to Eimeria and IB, as was shown by a higher feed intake and reduced weight loss. Optimal incubation as a single early life condition also had a positive influence on the adaptive response of layers toEimeria, as demonstrated by tendencies to higher feed intake and BW gain, less duodenal lesions and a lower oocyst production. Early feeding resulted in higher body and organ weights, a changed microbiota composition in the intestines, and a changed response to E. acervulina and LPS/HuSA. Colistin treatment resulted in a changed microbiota composition of the intestines and a changed response to E. acervulina and LPS/HuSA. These results confirmed the hypothesis that early life conditions can be used to influence the adaptive capacity to infectious challenges. In conclusion, improving the adaptive capacity with the use of particular early life conditions may be the first step towards an alternative method to maintain or improve layer health and disease resistance.

    Rumen-protected rice bran to induce the adaptation of calcium metabolism in dairy cows
    Martín-Tereso López, J. - \ 2010
    Wageningen University. Promotor(en): Martin Verstegen; Leonard den Hartog, co-promotor(en): H. van Laar. - [S.l. : S.n. - ISBN 9789085856085 - 182
    melkkoeien - rijstzemelen - calcium - pensmetabolisme - pensfermentatie - melkziekte - voer - rundveevoeding - diervoeding - voedingsfysiologie - adaptatiefysiologie - dierziektepreventie - dairy cows - rice bran - calcium - rumen metabolism - rumen fermentation - parturient paresis - feeds - cattle feeding - animal nutrition - nutrition physiology - adaptation physiology - animal disease prevention
    Dairy cows suffer from hypocalcaemia in the days around calving, which may result in a condition generally known as milk fever. Calcium metabolism sharply shifts at the start of lactation, because Ca needs suddenly become much greater than at the end of gestation. Calcium metabolism is able to adapt to different physiological situations, but adaptation requires several days to be effective, resulting in this transient hypocalcaemia. A way to prevent milk fever is to induce adaptation of Ca metabolism weeks before calving by reducing dietary availability of Ca, to prepare Ca metabolism for calving. Rice bran contains a very low level of Ca and a high level of phytic acid, which is a well-know dietary antagonist of Ca in monogastric species. Preventing the ruminal degradation of phytic acid, rice bran can reduce the nutritional availability of dietary Ca in cows. In this thesis, fat coating and formaldehyde treatment proved effective to protect phytic acid in rice bran from ruminal degradation. Formaldehyde treatment was chosen as the preferred method, because it had no detrimental effects on voluntary feed intake. Feeding rumen-protected rice bran reduced dietary Ca availability, thereby inducing the adaptation of Ca metabolism. Furthermore, the product, fed before calving to multiparous cows, improved calcaemia for the first three days after calving. Rumen-protected rice bran, fed in the last weeks of gestation, could represent a practical dietary strategy to prevent milk fever.

    De evolutionaire dimensie van duurzaam visserijbeheer
    Rijnsdorp, A.D. - \ 2008
    IJmuiden : IMARES (Rapport / Wageningen IMARES C105/08) - 19
    visserij - visserijbeheer - evolutionaire genetica - adaptatiefysiologie - soortvorming - duurzaamheid (sustainability) - fisheries - fishery management - evolutionary genetics - adaptation physiology - speciation - sustainability
    Dit rapport behandelt de evolutionaire consequenties van visserij en de implicaties hiervan voor het duurzaam beheer. Visserij verhoogt de kans dat vissen worden weggevangen voordat ze volwassen worden en zich kunnen voortplanten. Dit betekent dat de dieren die genetisch geprogrammeerd zijn om op jongere leeftijd volwassen te meer nakomelingen zullen produceren dan dieren die pas op latere leeftijd volwassen worden. Een andere eigenschap die beïnvloed kan worden is de voortplantingsinspanning (aantal eieren) en de groeisnelheid. Dieren die meer eieren produceren zijn in het voordeel. Een verlaging van de geslachtsrijpe leeftijd en een verhoging van de voortplantingsinspanning resulteert in een afname van de groeisnelheid. Visserij leidt dus tot verschuivingen in de genetische eigenschappen (evolutionaire veranderingen) van de geëxploiteerde bestanden. In dit rapport wordt een overzicht gegevens van de huidige wetenschappelijk inzichten in de door de visserijgeïnduceerde evolutie en de implicaties die dit heeft voor het visserijbeheer. Speciale aandacht wordt gegeven aan de beschikbare kennis over Noordzee platvis en de mogelijkheden die er zijn om op basis van deze kennis tot een Evolutionair Impact Assessment voor deze bestanden te komen.
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