In piglets, the post-weaning growth check is commonly associated with the weaning process that occurs within the European Union at approximately 3-4 weeks of age. The aims of the studies reported here were to investigate the contribution and importance of nutritional influences on the complex and multi-factorial problem of the post-weaning growth check in the piglet. Multi-disciplinary investigations focussed upon the relationship between post-weaning nutrition and the gut ecosystem with specific emphasis on gut physiology, immunity and microflora. The influence of dietary acid binding-capacity (ABC) on gut morphology characteristics was investigated in 20 newly-weaned piglets up to 14 days post-weaning. Piglets offered the low ABC diet displayed more rapid recovery of villus height (after a degree of villus atrophy) than control animals (P<0.001). Prior to the initial villus atrophy, villus height increased significantly throughout the experimental period for both dietary treatment groups (P<0.001; <0.001 (L); <0.001 (Q)). In control animals, villus width was greater (P=0.006) compared with treatment animals, and villus width increased over time for both groups (P<0.001; <0.001 (L); 0.014 (Q)). Crypt depth also increased temporally (P<0.001; <0.001 (L)) for both dietary groups, with treatment animals exhibiting the greatest overall dietary mean (P=0.009). No significant differences between ileal digesta pH and feed intake levels were determined. Despite the improvements in intestinal structure post-weaning, these effects were not manifested in increased performance, i.e. DLWG. The improvements in intestinal structure may not have been of significant magnitude to influence performance parameters. Dietary zinc oxide (ZnO) and avilamycin supplementation was found to exert a beneficial (although non-significant: P>0.05) effect on gut morphology; villus atrophy occurred over the initial 2 days post-weaning for animals fed ZnO, avilamycin or ZnO plus avilamycin (diets 2-4 respectively), compared to 4 days for control animals. No significant differences between intestinal coliform and lactobacilli load were established with respect to dietary treatment. Any differences observed in microflora load are most likely to be age-dependent. A positive relationship was established between dietary treatment (ZnO, avilamycin and ZnO plus avilamycin) on daily live weight gain post-weaning (P<0.001). Although not significant (P>0.05), a positive influence of dietary ZnO supplementation on feed intake levels was apparent, which may account, in part, for the enhanced growth performance. This finding was not however manifested through modifications of intestinal morphology or the lactobacilli and coliform populations studied. This further suggests that dietary ZnO may exert an effect either luminally or systemically. Further research is required to determine the mechanism responsible for the enhanced feed intake and DLWG response. The effects of feeding a yeast-based nucleotide source pre- and post-weaning revealed no significant differences with respect to villus height and width. Crypt depth was significantly greater in animals fed the treatment diet post-weaning (P<0.001). Post-weaning nucleotide-supplemented diets were found to significantly reduce intestinal coliform load (P=0.033). Such an effect was not evident in animals fed the diets pre-weaning, suggesting that the gut microflora may have adapted to the dietary regimen throughout the pre-weaning period. Lymphocyte blastogenesis assays revealed that piglets fed a yeast-based nucleotide source post-weaning might be immunosuppressed at the time weaning. Conversely, when the same diets (in terms of composition) were fed from 14 days pre-weaning (study 4), no indication of immunosuppression was evident. Since no dietary effects were apparent in either study, it is postulated that this could be a general effect of the diet per se and not the actual dietary composition. It is however also possible that the animals involved in study 4 were experiencing hypersensitivity reactions to the pre-weaning dietary antigens. These animals were also combating an E. coli infection. Additional studies are however required to identify conclusively a cause and effect relationship, and elucidate the complicated interactions between nutrition or feed intake and immunobiology in the post-weaned piglet. Implementation of dietary nucleotide-supplementation from 7 days pre-weaning through to 25 days post-weaning within a commercial environment was found to enhance significantly DLWG (P<0.001). In summary, the current work extends current knowledge and offers a greater understanding of the factors and complex process that influence the gut ecosystem and physiology in the post-weaned piglet. This thesis confirms the crucial role feed intake or, more specifically luminal nutrition, in post-weaned piglets and has highlighted key areas for future investigation.

20 Large White x Landrace sows were kept throughout 4 parities on 1 of 2 exercise treatments, free (F) or restricted (R), imposed at 2 stages of the production cycle (namely gestation and farrowing/lactation), thus giving 4 treatments: FF, FR, RF and RR. During gestation, the sows were housed in cubicles - group a being tethered while group F were allowed unrestricted movement within the cubicle and dunging area. From day 110 of gestation to weaning, all sows were kept in the same farrowing house, group R in conventional crates, group F in strawed pens. Management of the sows was otherwise identical. All farrowings were monitored with regard to the duration of parturition and stillbirth rate, while various behavioural and physiological measurements were recorded as indicators of piglet viability. Observations were also made of now behaviour at various stages of the production cycle. There were significant (P< 0.001) behavioural differences in gestation with groups R and F spending 45% v. 25% of the time lying and 27% v. 42% in manipulating straw. There were also significant (P<0.001) differences in amount and type of locomotor activity with the restricted sows making more minor movements while the free sows made more pace movements. At farrowing, all sows showed increased restlessness but group a made more leg movements and exhibited significantly (P<0.01) more straining and quivering (both pre- and intrapartum) than group F, although the latter stood and nested more frequently during the farrowing process (P< 0.001). There were no significant differences between treatments during lactation. In terms of reproductive performance, the differences between treatments were non significant, but sows in pens (group F) farrowed more quickly (a mean birth interval of 21 v. 39 minutes), produced more live pigs (11.3 v. 10.5) and fewer stillborn pigs (0.5 v. 0.8) per litter, than sows in crates (group a). Group F sows also produced piglets which had been subjected to less hypoxia as evidenced by their lower (P <0-05) serum lactic acid levels at birth (140 v. 158 m.I.U./ml) although there were no significant differences between piglets of groups F and R in times taken to breathe following birth or (53 v. 45 seconds), to suckle (36 v. 32 minutes) or in plasma immunoglobulin levels at 36 hours post partum (41.5 v. 41.7 mg/ml). Neither were there any significant treatment effects on piglet growth rate and pre-weaning mortality.

Leptin is produced primarily by white adipose tissue but also by brown adipose tissue (BAT) and the placenta. It has a major physiological role in the control of energy balance. BAT is critically important for the initiation of non-shivering thermogenesis in precocial newborns through the uncoupling protein, UCP1 unique to BAT. This is particularly important in neonatal lambs and infants in which levels of UCP1 peak at birth concomitant with a peak in plasma leptin and a surge in Cortisol. Other mitochondrial proteins may contribute to this effect e.g. VDAC which is located in the outer mitochondrial membrane. The aim of this thesis was to: 1. investigate the role of the late gestation Cortisol surge on BAT development 2. investigate the effect of route of delivery on subsequent neonatal plasma leptin concentrations 3. assess the effect of leptin administration to neonatal lambs on thermoregulation Late gestation fetuses were infused with Cortisol or saline or underwent adrenalectomy or sham operation. BAT was sampled at 129 and 144 days of gestation, respectively. UCPl abundance was significantly increased in the animals receiving Cortisol treatment compared to controls and was significantly reduced in adrenalectomised animals. Plasma leptin was analysed from lambs delivered vaginally or near term by caesarean section (CS). Cord plasma leptin decreased significantly after birth, an adaptation that was delayed by CS delivery. Acute and chronic administration of leptin to neonatal lambs improved thermoregulation by preventing a decline in body temperature. Chronic leptin treatment over 7 days (lOOp-g daily) promoted the loss of UCP1 mRNA and protein, but had no deleterious effects on body temperature. Polyclonal antibodies were developed against mitchondrial voltage-dependent anion channel (VDAC). The postnatal ontogeny of VDAC was found to be similar to that of UCP1 and cytochrome c, with abundance peaking around one day of age. VDAC was found in high abundance in organs with high metabolic requirements such as heart, muscle and BAT. These results suggest that VDAC is involved in ensuring BAT maintains a maximal rate of thermogenesis after birth. In conclusion, I have shown for the first time that leptin has an important role in thermogenesis during the transition from fetal to neonatal life. This is attenuated in CS animals, possibly linked to a reduced sympathetic nervous system activity. The rapid loss of UCP1 mRNA, which occurs within the first few days of life, appears to be modulated by leptin, possibly stimulating the development of white adipose tissue and generation of body heat through mechanisms other than nonshivering thermogenesis in BAT. VDAC may be important during this period in ensuring adequate substrate delivery to BAT. Intact adrenal glands are also necessary for the increase in UCP1 abundance during late gestation, an effect mediated in part by Cortisol. NB. This ethesis has been created by scanning the typescript original and may contain inaccuracies. In case of difficulty, please refer to the original text.

The biological activity and genomic variation of five Kenyan, three Asian and two sublethal isolates of Plutella xylostella granulovirus (PlxyGV) were determined and compared in P. xylostella larvae reared on artificial diet. Optimal production of PlxyGV occlusion bodies (occluded virus, OB) was observed in larvae reared in isolation rather than communally. Incorporation of a juvenile hormone analogue in the artificial diet increased OB production seven times. The pathogenicity and infectivity of the isolates was compared using neonate P. xylostella. A single Kenyan isolate (PlxyGV-2.18) was shown to have a significantly shorter median lethal time to death (LT50) than the other nine isolates in other geographical populations of P. xylostella. No synergism was observed between the isolates in mixed inoculations of P. xylostella and a slower killing isolate predominated over a faster killing isolate in mixed inoculations. The presence and nature of “sub-lethal” infections of PlxyGV observed in stock cultures of P. xylostella collected in Kenya and England was studied. Sub-lethal infections were observed in approximately 23% of apparently healthy stock larvae from two of the stocks of P. xylostella (one from England and one from Kenya) but was absent from a third stock originating in England. It was possible to isolate OBs from apparently healthy P. xylostella larvae in the two virus positive stocks, indicating some productive infection. The sub-lethal isolates had similar pathogenicity and infectivity to the other Kenyan and Asian isolates (excluding PlxyGV-2.18). The genomes of the isolates were compared by restriction fragment length profiling and by sequencing specific regions of the viral genome.

<p> The successful application of whole wheat in the EU indicated that dietary structural material, such as coarsely ground corn (CC), could be included in US broiler diets to improve live performance. The main objective of this study was to evaluate the effects of broiler feed structure and litter conditions on broiler live performance, nutrient digestibility, and gastrointestinal tract (GIT) development and function in different scenarios. It was hypothesized that dietary CC inclusion and new litter condition may significantly improve broiler live performance and nutrient digestibility, as well as influence the functional development and motility of the broiler GIT. We also hypothesized that dietary CC would decrease feed cost and litter nitrogen, moisture, and ammonia emission. Our objective was to understand and quantify the effects of dietary structural material inclusion and litter management on broiler live performance and development of different GIT sections by measuring the relevant physical, morphological, and histological parameters of the GIT during broiler feeding trials. </p><p> Therefore, the focus of this dissertation was: 1) to study the impact of corn particle size distribution with litter conditions on broiler live performance and nutrient digestibility; 2) to investigate the influence of corn particle size distribution and litter condition on broiler GIT development and function by measuring the relevant physical, morphological, and histological parameters; 3) to investigate the effects of corn particle size distribution on broiler litter nitrogen, moisture, and ammonia emission; and 4) to quantify and develop a feeding regime of dietary corn particle size distribution that decreased feed cost while optimizing broiler live performance and GIT development and function. </p><p> The dissertation research carried out 2 cages studies, 4 floor studies, and 1 grinding cost analysis study. Experiment 1 evaluated the effects of six dietary CC inclusion levels in two feed form on broiler live performance, BW uniformity, relative gizzard weight, fecal nitrogen, and particle size preference behaviors of broiler raised in cages from 0 to 14 d of age. Experiment 2 and 3 investigated the effects of gender, litter conditions, and dietary CC inclusion on live performance, gizzard and proventriculus development, litter characteristics, and colon bacterial profiles of broiler raised on a litter-covered floor from 0 to 49 d of age. Experiment 4 was a 45 d cage study that investigated the effects of three dietary CC inclusions on broiler live performance, GIT development, apparent ileal digestibility (AID) of energy and nitrogen, jejunum digesta particle size distribution, and feed retention time. Experiment 5 evaluated the effects of two dietary CC inclusions and two litter conditions on broiler live performance, litter characteristics, GIT development, apparent ileal digestibility of energy and nitrogen, and intestinal morphology. Experiment 6 investigated the effects of two dietary CC inclusion and three different floor types on broiler live performance, litter characteristics, GIT development, apparent ileal digestibility of energy and nitrogen, intestinal morphology, and ammonia emission. Corn grinding cost by hammermill and roller mill was also compared. </p><p> In conclusion, dietary CC inclusion decreased feed cost, improved nitrogen and energy digestibility, altered GIT bacterial population, improved feed efficiency, and reduced litter ammonia emission through the modulation of GIT function as evidenced by increased gizzard weight, greater digesta retention time, decreased digesta pH, modified intestinal morphology structure, and decreased litter moisture and nitrogen. We also found that the effects of dietary CC inclusion could confound pellet quality, while new litter had only a marginal benefit on broiler live performance. Particle size distribution was found to be more important than the geometric mean diameter by mass (dgw) with regard to the paradoxical role of particle size on poultry feed manufacturing and nutrition.</p>

No description available.

Currently, the quality of oocytes matured in vitro is still not satisfactory. In fact, only 5-10% of oocytes were evaluated to be intrinsically capable to produce in vitro embryos with full developmental competence. Recent studies have highlighted the importance of epigenetics, a mechanism controlling activation and repression of gene expression, in embryonic development. Indeed, several proteins involved in histone modifications including histone deacetylase 1 (HDAC-1), lysine specific demethylase 1 (LSD-1), and brahma related gene 1 (BRG-1) were shown vital to early development. We described the presence of these proteins during porcine oocyte maturation and embryo development and investigated whether these proteins were also involved in the regulation of developmental competence. We detected the three proteins in all stages of development, but nuclear localization was not always confirmed. We noticed that these three proteins followed the same general trend before activation but while the fluorescence signal of HDAC-1 increased after activation those of LSD-1 and BRG-1 decreased. Moreover, oocytes and embryos of lower developmental competence were observed to have differences in the fluorescence signal of HDAC-1, LSD-1, and BRG-1. The occurrence of targeted LSD-1 histone modifications, histone 3 lysine 4 mono- (H3K4me1) and di- (H3K4me2) methylation, were also found to be different in embryos of different developmental competence. This study suggests that HDAC-1, LSD-1 and BRG-1 are developmentally regulated during early development of swine embryos and are potentially involved in the acquisition of the embryonic developmental competence. / Aujourd'hui, la qualité des ovocytes maturés in vitro n'est toujours pas satisfaisante. En effet, seulement 5 à 10% des ovocytes peuvent intrinsèquement engendrer in vitro des embryons avec entière compétence développementale. Récemment, des études ont montré l'importance qu'a l'épigénome, mécanisme qui active ou inhibe l'expression des gènes, dans le développement embryonnaire. Effectivement, plusieurs protéines reconnues capables de modifier les histones telles que l'histone déacétylase 1 (HDAC-1), la déméthylase spécifique aux lysines 1 (LSD-1), ainsi que le gène brahma related 1 (BRG-1), ont été démontrées vitales aux premiers stades développementaux. Nos expériences ont pour buts de décrire par immuno-détection la présence des ces protéines pendant la maturation méiotique et le développement d'ovocytes et d'embryons porcins et de savoir si ces protéines sont aussi impliquées dans la régulation de la compétence développementale de ces-derniers. Nous avons décelé la présence des trois protéines à tous les stades de développement bien que leurs localisations nucléiques n'aient pas été toujours confirmées. De plus, nous avons observé que l'intensité du signal de fluorescence des trois protéines fluctue similairement au cours de la maturation des ovocytes. Cependant, après l'activation, la fluorescence de HDAC-1 augmente alors que celles de LSD-1 et BRG-1 diminuent. D'autre part, nous avons pu constater que les ovocytes et embryons de moindre compétence développementale présentent des différences de fluorescence pour les trois protéines étudiées. En outre, nous avons également détecté des différences dans la présence de mono- (H3K4me1) et di- (H3K4me2) méthylations sur la 4e lysine de l'histone 3, cibles de LSD-1, dans des embryons de différentes compétences développementales. Cette étude suggère que les protéines HDAC-1, LSD-1 et BRG-1 sont régulées aux premiers stades de développement po

Four studies were conducted using high water soluble carbohydrate (WSC), sweet (SM) and low WSC, regular (RM) pearl millet and high WSC (SS) and low WSC (RS) sorghum cultivars. The first and the second studies evaluated the chemical composition and ensiling characteristics of those cultivars. Millet cultivar had no effect on pH. SM silage contained less neutral and acid detergent fiber than RM silage. SS cultivar had less pH than RS cultivar at any ensiling period. RS silage contained greater acid detergent lignin and less non protein nitrogen than SS silage. The third and the fourth studies investigated the feeding value of SM and SS silages. Cows fed SM silage produced milk with greater fat concentration, energy corrected milk, 4% fat corrected milk, and solid corrected milk yield than cows fed corn silage. Milk fat was greater, while milk yield and lactose concentration were less for cows fed SS silage than cows fed alfalfa silage. In conclusion, there is a good potential for pearl millet silage as a source of forage for dairy cows. Further investigations are required to optimize the feeding value of sorghum silage. / Quatre études ont été conduites utilisant deux variétés de millet perlé [i.e. riches en glucides solubles (GS) (MS) et pauvre en GS (MR)] ainsi que deux variétés de sorgho [i.e. riches en GS (SS) et pauvre en GS (SR)]. Les première et deuxième études évaluèrent la composition chimique et les caractéristiques d'ensilage des différentes variétés. La variété de millet n'eut pas d'effet sur le pH. L'ensilage de MS contenait moins de fibre NDF et ADF que l'ensilage de MR. La variété de SS avait un pH inférieur au SR à tout moment lors de la période d'ensilage. L'ensilage de SR contenait une quantité supérieure de lignine et moins d'azote non protéique que l'ensilage de SS. Les troisième et quatrième études investiguèrent la valeur nutritive des ensilages de MS et SS. Les vaches soignées à l'ensilage de MS ont produit du lait plus concentré en gras, énergie du lait corrigée, 4% gras du lait corrigé et rendement en solides du lait corrigé que les vaches soignées à l'ensilage de maïs. La concentration en gras du lait était la même tandis que le rendement en lait et la concentration en lactose furent inférieurs pour les vaches soignées à l'ensilage de SS comparativement à celle soignées à l'ensilage de luzerne. En conclusion, il y a un grand potentiel pour l'ensilage de millet perlé en tant que source de fourrage pour les vaches laitières. D'autres études seraient nécessaires pour optimiser les valeurs nutritives de l'ensilage de sorgho.

The influence of 4, 5 and 6 generations of selection for duration of fertility of frozen-thawed chicken semen on fertility and hatchability of frozen-thawed semen, fertility of fresh semen, semen volume, concentration of spermatozoa, spermatozoal motility and on spermatozoa and seminal plasma cholesterol and phospholipid levels and their ratios (generations 5 and 6) as well as the genetic influence on these traits was studied. A selected line and an unselected control line of broiler chickens were used. / All estimates of fertility of frozen-thawed and fresh semen were significantly (P 0.05). / The heritabilities of fertility of frozen-thawed and fresh semen and semen characteristics were generally low and those for spermatozoa lipid levels and their ratios were generally medium. / The positive phenotypic correlations between estimates of fertility within frozen-thawed and fresh semen were high but low between fertility of frozen-thawed and fresh semen. The phenotypic correlations between semen characteristics and fertility were inconsistent. The phenotypic correlations of spermatozoa and seminal plasma cholesterol with fertility of frozen-thawed semen were negative as were the phenotypic correlations of seminal plasma cholesterol with fertility of fresh semen. Genetic correlations were also calculated and were similar in direction to the phenotypic correlations but their magnitudes exceeded unity in many cases. The level of inbreeding was uncorrelated with either fertility, semen characteristics, spermatozoa and seminal plasma lipids or their ratios.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006. / Source: Dissertation Abstracts International, Volume: 68-02, Section: B, page: 0677. Adviser: James K. Drackley. Includes bibliographical references. Available on microfilm from Pro Quest Information and Learning.