Staff Publications

Staff Publications

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    '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.

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Early Methanogenic Colonisation in the Faeces of Meishan and Yorkshire Piglets as Determined by Pyrosequencing Analysis
Su, Y. ; Bian, G.R. ; Zhu, Z.G. ; Smidt, H. ; Zhu, W.Y. - \ 2014
Archaea : an international microbiological journal 2014 (2014). - ISSN 1472-3646
gut microbiota - methanobrevibacter-smithii - intestinal microbiota - postnatal-development - sequence-analysis - bacterial - lactobacillus - community - archaeal - methane
Gut methanogenic archaea of monogastric animals are considered to be related to energy metabolism and adipose deposition of the host; however, information on their development in young piglets is limited. Thus, to investigate early methanogenic colonisation in the faeces of Meishan and Yorkshire piglets, faecal samples were collected from piglets at 1, 3, 7, and 14 days after birth and used to analyse the methanogenic community with 16S rRNA gene pyrosequencing. Results showed that the diversity of the methanogenic community in the faeces of neonatal piglets decreased from one to 14 days of age, as the total methanogen populations increased. The age of piglets, but not the breed, significantly affected the diversity of the methanogenic community which was dominated by the genus Methanobrevibacter. From the ages of one to 14 days, the abundance of M. smithii-related operational taxonomic units (OTUs) increased significantly, while the abundances of M. thaueri- and M. millerae-related OTUs decreased significantly. The substitution of M. smithii for M. thaueri/M. millerae was faster in Yorkshire piglets than in Meishan piglets. These results suggest that the early establishment of microbiota in neonatal piglets is accompanied by dramatic changes in the methanogenic community, and that the changes vary among pigs of different genotypes.
Time course and role of luteinizing hormone and follicle-stimulating hormone in the expansion of the Leydig cell population at the time of puberty in the rhesus monkey (Macaca mulatta)
Verhagen, I. ; Ramaswamy, S. ; Teerds, K.J. ; Keijer, J. ; Plant, T.M. - \ 2014
Andrology 2 (2014)6. - ISSN 2047-2927 - p. 924 - 930.
gonadotropin-secretion - postnatal-development - human testis - proliferation - testosterone - fsh - differentiation - fascicularis - spermatogonia - localization
In higher primates, development of the adult population of Leydig cells has received little attention. Here, the emergence of 3beta-hydroxysteroid dehydrogenase (HSD3B) positive cells in the testis of the rhesus monkey was examined during spontaneous puberty, and correlated with S-phase labeling in the interstitium at this critical stage of development. In addition, the relative role of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in initiating the pubertal expansion of Leydig cells was studied by precociously stimulating the juvenile testis in vivo with pulsatile 11-day infusions of recombinant LH and FSH, either alone or in combination. At the time of castration, testes were immersion fixed in Bouin's, embedded in paraffin, and sectioned at 5mum. Leydig cells/testis were enumerated using HSD3B as a Leydig cell marker. Leydig cell number per testis increased progressively during puberty to reach values in the adult approximately 10 fold greater than in early-pubertal animals. The rise in cell number was associated with an increase in nuclear diameter. That the pubertal expansion of Leydig cell number was driven primarily by the increase in LH secretion at this stage of development was suggested by the finding that precocious stimulation of mid-juvenile monkeys with LH, either alone or in combination with that of FSH, resulted in a 20-30 fold increase in the number of HSD3B-positive cells. Interestingly, precocious FSH stimulation, alone, also resulted in appearance of Leydig cells as indicated by the occasional HSD3B-positive cell in the interstitium. The nuclear diameter of these Leydig cells, however, was less than that of those generated in response to LH.
A defined intestinal colonization microbiota for gnotobiotic pigs
Laycock, G. ; Sait, L. ; Inman, C. ; Lewis, M. ; Smidt, H. ; Diemen, P. van; Jorgensen, F. ; Stevens, M. ; Bailey, M. - \ 2012
Veterinary Immunology and Immunopathology 149 (2012)3-4. - ISSN 0165-2427 - p. 216 - 224.
antibody repertoire development - germ-free pigs - real-time pcr - immune-system - gastrointestinal-tract - postnatal-development - filamentous bacteria - newborn piglets - oral tolerance - gut bacteria
Maximising the ability of piglets to survive exposure to pathogens is essential to reduce early piglet mortality, an important factor in efficient commercial pig production. Mortality rates can be influenced by many factors, including early colonization by microbial commensals. Here we describe the development of an intestinal microbiota, the Bristol microbiota, for use in gnotobiotic pigs and its influence on synthesis of systemic immunoglobulins. Such a microbiota will be of value in studies of the consequences of early microbial colonization on development of the intestinal immune system and subsequent susceptibility to disease. Gnotobiotic pig studies lack a well-established intestinal microbiota. The use of the Altered Schaedler Flora (ASF), a murine intestinal microbiota, to colonize the intestines of Caesarean-derived, gnotobiotic pigs prior to gut closure, resulted in unreliable colonization with most (but not all) strains of the ASF. Subsequently, a novel, simpler porcine microbiota was developed. The novel microbiota reliably colonized the length of the intestinal tract when administered to gnotobiotic piglets. No health problems were observed, and the novel microbiota induced a systemic increase in serum immunoglobulins, in particular IgA and IgM. The Bristol microbiota will be of value for highly controlled, reproducible experiments of the consequences of early microbial colonization on susceptibility to disease in neonatal piglets, and as a biomedical model for the impact of microbial colonization on development of the intestinal mucosa and immune system in neonates.
Rearing environment affects development of the immune system in neonates
Inman, C.F. ; Haverson, K. ; Konstantinov, S.R. ; Jones, P.H. ; Harris, C. ; Smidt, H. ; Miller, B. ; Bailey, M. ; Stokes, C. - \ 2010
Clinical and Experimental Immunology 160 (2010)3. - ISSN 0009-9104 - p. 431 - 439.
dendritic cells - lamina-propria - t-cells - postnatal-development - gnotobiotic pigs - small-intestine - atopic disease - swine model - allergy - bacteria
P>Early-life exposure to appropriate microbial flora drives expansion and development of an efficient immune system. Aberrant development results in increased likelihood of allergic disease or increased susceptibility to infection. Thus, factors affecting microbial colonization may also affect the direction of immune responses in later life. There is a need for a manipulable animal model of environmental influences on the development of microbiota and the immune system during early life. We assessed the effects of rearing under low- (farm, sow) and high-hygiene (isolator, milk formula) conditions on intestinal microbiota and immune development in neonatal piglets, because they can be removed from the mother in the first 24 h for rearing under controlled conditions and, due to placental structure, neither antibody nor antigen is transferred in utero. Microbiota in both groups was similar between 2 and 5 days. However, by 12-28 days, piglets reared on the mother had more diverse flora than siblings reared in isolators. Dendritic cells accumulated in the intestinal mucosa in both groups, but more rapidly in isolator piglets. Importantly, the minority of 2-5-day-old farm piglets whose microbiota resembled that of an older (12-28-day-old) pig also accumulated dendritic cells earlier than the other farm-reared piglets. Consistent with dendritic cell control of T cell function, the effects on T cells occurred at later time-points, and mucosal T cells from high-hygiene, isolator pigs made less interleukin (IL)-4 while systemic T cells made more IL-2. Neonatal piglets may be a valuable model for studies of the effects of interaction between microbiota and immune development on allergy.
Prenatal induced chronic dietary hypothyroidism delays but does not block adult-type Leydig cell development
Rijntjes, E. ; Teerds, K.J. ; Swarts, H.J. - \ 2009
American Journal of Physiology. Endocrinology and Metabolism 296 (2009)2. - ISSN 0193-1849 - p. E305 - E314.
rat sertoli cells - thyroid-hormone - neonatal-hypothyroidism - luteinizing-hormone - testicular development - postnatal-development - interstitial-cells - iodine deficiency - prepubertal rat - testis
Transient hypothyroidism induced by propyl-2-thiouracyl blocks postpartum Leydig cell development. In the present study, the effects of chronic hypothyroidism on the formation of this adult-type Leydig cell population were investigated, using a more physiological approach. Before mating, dams were put on a diet consisting of an iodide-poor feed supplemented with a low dose of perchlorate and, with their offspring, were kept on this diet until death. In the pups at day 12 postpartum, plasma thyroid-stimulating hormone levels were increased by 20-fold, whereas thyroxine and free tri-iodothyronine levels were severely depressed, confirming a hypothyroid condition. Adult-type progenitor Leydig cell formation and proliferation were reduced by 40¿60% on days 16 and 28 postpartum. This was followed by increased Leydig cell proliferation at later ages, suggesting a possible slower developmental onset of the adult-type Leydig cell population under hypothyroid conditions. Testosterone levels were increased 2- to 10-fold in the hypothyroid animals between days 21 and 42 postpartum compared with the age-matched controls. Combined with the decreased presence of 5-reductase, this implicates a lower production capacity of 5-reduced androgens. In 84-day-old rats, after correction for body weight-to-testis weight ratio, plasma insulin-like factor-3 levels were 35% lower in the hypothyroid animals, suggestive of a reduced Leydig cell population. This is confirmed by a 37% reduction in the Sertoli cell-to-Leydig cell ratio in hypothyroid rats. In conclusion, we show that dietary-induced hypothyroidism delays but, unlike propyl-2-thiouracyl, does not block the development of the adult-type Leydig cell population
Ecophysiology of the developing total bacterial and Lactobacillus communities in the terminal small intestine of weaning piglets
Pieper, R. ; Janzcyk, P. ; Zeyner, A. ; Smidt, H. ; Guiard, V. ; Souffrant, W.B. - \ 2008
Microbial Ecology 56 (2008)3. - ISSN 0095-3628 - p. 474 - 483.
in-situ hybridization - targeted oligonucleotide probes - fecal samples - gastrointestinal microbiota - postnatal-development - porcine microbiota - escherichia-coli - flow-cytometry - immune-system - lactic-acid
Weaning of the pig is generally regarded as a stressful event which could lead to clinical implications because of the changes in the intestinal ecosystem. The functional properties of microbiota inhabiting the pig's small intestine (SI), including lactobacilli which are assumed to exert health-promoting properties, are yet poorly described. Thus, we determined the ecophysiology of bacterial groups and within genus Lactobacillus in the SI of weaning piglets and the impact of dietary changes. The SI contents of 20 piglets, 4 killed at weaning (only sow milk and no creep feed) and 4 killed at 1, 2, 5, and 11 days post weaning (pw; cereal-based diet) were examined for bacterial cell count and bacterial metabolites by fluorescence in situ hybridization (FISH). Lactobacilli were the predominant group in the SI except at 1 day pw because of a marked reduction in their number. On day 11 pw, bifidobacteria and E. coli were not detected, and Enterobacteriaceae and members of the Clostridium coccoides/Eubacterium rectale cluster were only found occasionally. L. sobrius/L. amylovorus became dominant species whereas the abundance of L. salivarius and L. gasseri/johnsonii declined. Concentration of lactic acid increased pw whereas pH, volatile fatty acids, and ammonia decreased. Carbohydrate utilization of 76 Lactobacillus spp. isolates was studied revealing a shift from lactose and galactose to starch, cellobiose, and xylose, suggesting that the bacteria colonizing the SI of piglets adapt to the newly introduced nutrients during the early weaning period. Identification of isolates based on partial 16S rRNA gene sequence data and comparison with fermentation data furthermore suggested adaptation processes below the species level. The results of our study will help to understand intestinal bacterial ecophysiology and to develop nutritional regimes to prevent or counteract complications during the weaning transition
Involvement of the hypothalamic-pituitary-thyroid axis and its interaction with the hypothalamic-pituitary-adrenal axis in the ontogeny of avian thermoregulation: a review
Debonne, M. ; Baarendse, P.J.J. ; Brand, H. van den; Kemp, B. ; Bruggeman, V. ; Decuypere, E. - \ 2008
Worlds Poultry Science Journal 64 (2008)3. - ISSN 0043-9339 - p. 309 - 321.
corticotropin-releasing-factor - precocial japanese-quail - altricial european starlings - chick-embryo - immunocytochemical demonstration - postnatal-development - developmental-changes - thyrotropin release - neonatal chicks - growth-hormone
The emergence of thermoregulation in avian species is a complex matter in which neural as well as hormonal processes are involved. In a previous paper, the neural aspects of primary avian thermoregulation were discussed. In this paper the role of the hypothalamus-pituitary-thyroid axis (HPT-axis) and the hypothalamus-pituitary-adrenal axis (HPA-axis) in the ontogeny of avian thermoregulation is evaluated. The regulatory mechanisms and different important hormones of both axes, which have stimulatory or inhibitory effects, are discussed. Because the onset of functionality of the thermoregulatory system is of great interest, the ontogeny and functionality of the hormonal axes are clarified. There is a great difference between precocial and altricial birds in hormonal events as well as in neural processes which are involved in the emergence of thermoregulation. In precocial avian species the HPT-axis becomes functional during the mid- to late embryonic period while the same axis only becomes fully functional during the first week post-hatch in altricial avian species. As early as the sixties, the emergence of homeothermy in chickens was investigated. It was concluded that the thyroid gland plays an important role in the thermoregulatory mechanisms of newly hatched chicks. More recent studies however were not able to show any direct effect of the thyroid hormones on the thermoregulation of day-old chicks, although blocking the conversion of T4 to T3 caused a decrease in body temperature in young chicks. Thyrotropin releasing hormone (TRH) is known to act in thermoregulation in mammals and several authors have found an effect of TRH on the metabolism of young and older chicks. However, the exact mechanism still remains unclear. Because the HPT- and the HPA-axis show close relationships, the role of the HPA-axis in the ontogeny of thermoregulation is also taken into consideration in this review. In mammals as well as in birds, corticotropin releasing hormone (CRH) is involved in the primary thermoregulation. We conclude that the HPT-axis has an important role in the ontogeny of avian thermoregulation. The exact role of the HPA-axis remains largely unclear although at least CRH is definitely of some importance.
Oncostatin-M inhibits luteinizing hormone stimulated Leydig cell progenitor formation in vitro
Teerds, K.J. ; Dissel-Emiliani, F.M.F. van; Miguel, M.P. de; Boer-Brouwer, M. de; Körting, L.M. ; Rijntjes, E. - \ 2007
Reproductive Biology and Endocrinology 5 (2007)43. - ISSN 1477-7827 - p. 1 - 9.
receptor knockout mice - rat testis - sertoli-cells - mouse testis - testicular development - postnatal-development - interstitial-cells - gene-expression - germ-cells - factor lif
Background: The initial steps of stem Leydig cell differentiation into steroid producing progenitor cells are thought to take place independent of luteinizing hormone (LH), under the influence of locally produced factors such as leukaemia inhibitory factor (LIF), platelet derived growth factor A and stem cell factor. For the formation of a normal sized Leydig cell population in the adult testis, the presence of LH appears to be essential. Oncostatin M (OSM) is a multifunctional cytokine and member of the interleukin (IL)-6 family that also includes other cytokines such as LIF. In the rat OSM is highly expressed in the late fetal and neonatal testis, and may thus be a candidate factor involved in Leydig cell progenitor formation. Methods: Interstitial cells were isolated from 13-day-old rat testes and cultured for 1, 3 or 8 days in the presence of different doses of OSM ( range: 0.01 to 10 ng/ml) alone or in combination with LH ( 1 ng/ml). The effects of OSM and LH on cell proliferation were determined by incubating the cultures with [3H] thymidine or bromodeoxyuridine ( BrdU). Developing progenitor cells were identified histochemically by the presence of the marker enzyme 3beta-hydroxysteroid dehydrogenase (3beta-HSD). Results: OSM, when added at a dose of 10 ng/ml, caused a nearly 2-fold increase in the percentage of Leydig cell progenitors after 8 days of culture. Immunohistochemical double labelling experiments with 3beta-HSD and BrdU antibodies showed that this increase was the result of differentiation of stem Leydig cells/precursor cells and not caused by proliferation of progenitor cells themselves. The addition of LH to the cultures consistently resulted in an increase in progenitor formation throughout the culture period. Surprisingly, when OSM and LH were added together, the LH induced rise in progenitor cells was significantly inhibited after 3 and 8 days of culture. Conclusion: Taken together, the results of the present study suggest that locally produced OSM may not only play a role in the regulation of Sertoli cell proliferation and the initiation of spermatogenesis but may also play a role in the regulation of Leydig cell progenitor formation by keeping the augmenting effects of LH on this process in abeyance.
The development of rat Leydig cell progenitors in vitro: how essential is luteinising hormone?
Teerds, K.J. ; Rijntjes, E. ; Veldhuizen-Tsoerkan, M.B. ; Rommerts, F.F.G. ; Boer-Brouwer, M. de - \ 2007
Journal of Endocrinology 194 (2007)3. - ISSN 0022-0795 - p. 579 - 593.
follicle-stimulating-hormone - ethylene dimethane sulfonate - human chorionic-gonadotropin - postnatal-development - testicular development - androgen biosynthesis - interstitial-cells - gene-expression - sertoli cells - knockout mice
Luteinising hormone(LH) appears to be important for the establishment of the adult-type Leydig cell population. The role of LH in the initial steps of stem Leydig cell/precursor cell differentiation is less clear. The aim of the present study was to elucidate the role of LH in the differentiation of spindle-shaped mesenchymal-like cells into Leydig cell progenitors. Interstitial cells were isolated from rat testes at three different ages reflecting different phases in development, and cultured in the presence of increasing concentrations of LH (ranging from 0.01 to 10 ng/ml). Cells were isolated from 10-day-old rats when stem Leydig cells/precursor cells are abundant; 13-day-old rats when the first 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD)-positive Leydig cell progenitors have developed in the strain of rats used in this study; and 18-day-old rats just prior to the wave of progenitor proliferation. Immunohistochemistry revealed that before stem Leydig cells differentiate into progenitor cells, they acquire functional LH receptors and become precursor cells. This was confirmed by an in vivo immunohistochemical double-labelling experiment. Addition of LH to the cultures increased the percentage of LH/3 beta-HSD-labelled Leydig cell progenitors, while the percentage of cells solely expressing the LH receptor decreased. Cell proliferation was negligible, suggesting that the increase in 3 beta-HSD-positive cells is the result of precursor cell differentiation. When interstitial cells were isolated from 13-day-old rats and to a lesser extent from 10-day old rats, a small proportion of the precursors could develop into progenitor cells independent of the presence of LH. In conclusion: before Leydig stem cells differentiate into 3 beta-HSD-positive progenitor cells, they acquire LH receptors and become precursor cells. LH appears to be essential, even at very low doses for the differentiation of these precursor cells into 3 beta-HSD-positive progenitors, although a subpopulation of precursor cells can develop into progenitors independently of LH.
Neuronal Number, Volume, and Apoptosis of the Left Dentate Gyrus of Chronically Stressed Pigs Correlate Negatively With Basal Saliva Cortisol Levels
Beek, E.M. van der; Wiegant, V.M. ; Schouten, W.G.P. ; Eerdenburg, F.J.C.M. van; Loijens, L.W.S. ; Plas, C. ; Benning, M.A. ; Vries, H. de; Kloet, E.R. de; Lucassen, P.J. - \ 2004
Hippocampus 14 (2004)6. - ISSN 1050-9631 - p. 688 - 700.
pituitary-adrenal axis - chronic psychosocial stress - unipolar major depression - granule cell layer - hippocampal volume - glucocorticoid-receptors - postnatal-development - stereotyped behavior - alzheimers-disease - hypoxia-ischemia
Although the consequences of stress and hypercortisolemia for the rodent hippocampal dentate gyrus (DG) are well known, little is known about other species. For pigs, tethered housing represents a well-established chronic stressor that shares many similarities with restraint paradigms, as evidenced by profound changes in behavior and autonomic and endocrine dysfunction, including flattened cortisol rhythms and hypercortisolemia all conditions that may threaten hippocampal viability in rat. Here, we studied structural parameters of the porcine DG after 5 months of tethered housing in relation to basal saliva cortisol measured antemortem. We further investigated whether any neuropathology or alterations in apoptosis had occurred in the left hippocampal hemisphere. Stereological analysis revealed high correlations between DG volume and neuron number in individual animals in both hemispheres. Within individual animals, neuron numbers of the left and right lobes were not correlated. Notably, basal cortisol was negatively correlated with volume and neuron number of the left, but not the right DG. Although obvious neuropathology was absent, apoptosis was present in DG and alveus and less so in CA areas. Despite the short window of time during which apoptosis is detectable, their stereologically estimated numbers in the DG, but not in other regions, were negatively correlated with cortisol. In conclusion, our data indicate for the first time a profound lateralization in the relationship between DG structure, apoptosis, and basal cortisol after stress in pigs. Five months of chronic stress failed to induce lasting neuropathology. Although accumulating changes in apoptosis could have contributed to the structural DG alterations, further studies should reveal whether stress has been instrumental, or whether the differences between animals were present from birth onward. The present lateralization after stress is, however, consistent with lateralized hippocampal volume changes in stress-related human disorders and suggests that these effects are not limited to this species alone.
Mechanism of thyroid-hormone regulated expression of the SERCA genes in skeletal muscle: Implications for thermogenesis
Simonides, W.S. ; Thelen, M.H.M. ; Linden, C.G. van der; Muller, A. ; Hardeveld, C. - \ 2001
Bioscience Reports 21 (2001)2. - ISSN 0144-8463 - p. 139 - 154.
sarcoplasmic-reticulum ca2+-atpase - cold-acclimated ducklings - messenger-rna levels - heat-production - postnatal-development - differential expression - uncoupling protein - receptor isoforms - force development - twitch muscle
Thyroid hormone increases the Ca2+-ATPase activity of the sarcoplasmic reticulum (SR) in skeletal muscle, thereby increasing the energy-turnover associated with Ca2+-cycling during contraction and rest. The fast-muscle isoform of the Ca2+-ATPase (SERCA1) and the slow-muscle isoform (SERCA2a), are encoded by two genes that are transcriptionally regulated by T3. The SERCA1 isoform can be expressed to considerably higher levels than the SERCA2a isoform. The stimulation of transcription of the SERCA1 gene by T3 is mediated by two thyroid hormone response elements, located in the promoter of this gene. The intracellular [Ca2+] can modulate the effect of T3. The increase in SR Ca2+-ATPase activity seen when T3-levels rise above normal, results from the induction of SERCA1 expression in slow muscle fibers. Concomitant high levels of Ca2+-ATPase activity are associated with down-regulation of SERCA2a expression in these fibers. The observed T3-dependent increase in SERCA1 expression and associated Ca2+-ATPase activity will increase the overall metabolic rate of the organism significantly under normal conditions, because of the high average level of contractile activity of slow fibers. Given the rise in serum T3-levels during prolonged cold exposure, these data suggest that fiber-specific stimulation of SERCA1 expression contributes to the thermogenic response in non-shivering thermogenesis. This mechanism may be particularly relevant in larger mammals, which have a relatively high percentage of slow fibers in skeletal muscle, and which need to rely on tissues other than brown fat for the generation of extra heat
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