Doctor of Philosophy / Department of Animal Sciences and Industry / John M. Gonzalez / This series of studies focuses on the impact of intra-litter variation on fetal myogenesis, and the ability of porcine progenitor cells to respond to growth promoting stimuli. In study 1, the smallest (SM), median (ME), and largest (LG) male fetuses from each litter were selected for muscle morphometric analysis from gilts at d-60 ± 2 and 95 ± 2 of gestation. On d-60 and 95 of gestation LG fetuses had greater whole muscle cross-sectional area (CSA) than ME and SM fetuses, and ME fetuses had greater whole muscle CSA than SM fetuses. Indicating that SM and ME fetuses are on a delayed trajectory for myogenesis compared to LG fetuses. At d-60 the advanced trajectory of LG compared to ME fetuses was due to increased development of secondary muscle fibers; whereas, the advanced myogenic development of LG and ME fetuses compared to SM fetuses was due to the presence of fewer primary and secondary muscle fibers. At d-95 of gestation the advanced myogenic development of LG and ME was due to increased hypertrophy of secondary muscle fibers. For study 2, porcine fetal myoblasts (PFM) were isolated from SM, ME, and LG fetuses from d-60 ± 2 of gestation fetuses and for study 3, porcine satellite cells (PSC) were isolated from the piglet nearest the average body weight of the litter. Both myogenic cell types were utilized to evaluate effects of porcine plasma on proliferation, differentiation, and indications of protein synthesis. For the proliferation assay, cells were exposed to one of three treatments: high serum which consisted high-glucose Dulbecco's Modified Eagle Medium supplemented with 10% (vol/vol) fetal bovine serum, 2% (vol/vol) porcine serum, 100 U penicillan/mL, 100 µg of strepmycin/mL, and 20 µg of gentamicin/mL (HS), low serum which consisted of HS without 10% FBS (LS), and LS supplemented with 10% (wt/vol) porcine plasma (PP). Treatments for the differentiation and protein synthesis assays consisted of either HS or LS media that either contained porcine plasma at 10% (wt/vol; PPP) or 0% (wt/vol; PPN). The HS-PFM had a greater proliferation rate compared to the LS and PP-PFM, and PP-PFM had a greater proliferation rate compared to LS-PFM. The LG fetuses’ PFM had a reduced proliferation rate compared to SM and ME fetuses’ PFM, which were similar. The PPP-PFM had a decreased myotube diameter compared to PPN-PFM. Small fetuses’ PFM had a greater myotube diameter compared to ME and LG fetuses’ PFM, and ME fetuses’ PFM had a greater myotube diameter compared to LG fetuses’ PFM. The proliferation rate of PP-PSC was decreased compared to the HS- and LS-PSC, and HS-PSC had a greater proliferation rate compared to LS-PSC. The PPP-PSC had greater differentiation capacity and myotube diameter than PPN-PSC. In conjunction these results indicate divergent myogenic development among different fetal sizes within a litter and suggest that porcine plasma supplementation stimulates myogenic progenitor cell activity in an age specific manner.

Transportation of swine is an emerging welfare issue, especially for piglets weaned and then immediately transported. Weaned pigs fed starter diets containing SDPP display improved growth performance. The objective of this study was to determine effects of pre-weaning SDPP on indicators of health, welfare, and performance in transported weaned pigs. Pigs were assigned to treatments: I. SDPP + transport, II. Water + transport, III. SDPP + no transport, or IV. Water + no transport. Pigs received their gavage twice daily for 5 d prior to weaning. Pigs were weaned and either transported or moved directly to the wean-to-finish barn. Rectal temperatures and blood samples were obtained at weaning and after relocation. Body weight was determined on d 1, at weaning, after relocation, and at weekly intervals for 5 wk thereafter. Blood chemistry profiles and serum cortisol concentrations were also determined. Rectal temperature and potassium increased and calcium decreased after groups I and II were transported. Glucose was lowest in group II. Total protein was greater in group I compared to group III. Albumin was greatest in group I compared to all other groups. Sodium was greatest in group II compared to all other groups. Anion gap was greatest in group II compared to group IV. Cortisol, phosphorus, gamma-glutamyltransferase, and chloride, were greater in groups I and II after transportation. In summary, transportation impacted several physiological indicators of health and well-being in weaned pigs, and providing SDPP prior to weaning prevented transportation-induced changes in sodium, glucose, and anion gap levels. / Master of Science

L'objectiu és millorar els gels de plasma porcí induïts per calor a pH àcid utilitzant transglutaminasa microbiana (MTGasa). El tractament millora textura i CRA dels gels a pH 5,5, però les millores no són suficients per recuperar les pèrdues degut a l'acidificació. L'estructura globular de les proteïnes dificulta l'atac enzimàtic. La reactivitat de l'enzim no millora amb l'addició de cisteïna a plasma amb MTGasa. El tractament del plasma amb MTGasa sota alta pressió (HP) millora la duresa dels gels. No obstant, la CRA només millora lleugerament. La duresa es pot incrementar mantenint les solucions de plasma pressuritzat sota refrigeració, encara que no millora la CRA. Es pot concloure que les pèrdues en la textura dels gels de plasma induïts per calor a pH àcid es poden recuperar parcialment tractant amb MTGasa, especialment afegint cisteïna o sota HP. Encara que la CRA només es veu lleugerament millorada en el segon cas. / The objective of the thesis is to improve the heat-induced gel properties of porcine blood plasma at acid pH using microbial transglutaminase (MTGase). The enzymatic treatment enhances texture and WHC of plasma gels at pH 5.5, although increases are not enough to overcome loses on gelling properties. The globular structure of proteins can make the enzymatic attack difficult. The enzyme reactivity is not enhanced when cysteine is added to plasma treated with MTGase. Treating plasma with MTGase under HP increases hardness. However, WHC is only slightly modified. These achievements on hardness can be enhanced by holding pressurised-plasma solutions at refrigeration conditions. In contrast, it has no effects on WHC. Overall, losses in texture of heat-induced plasma gels at acid pH are recovered to an important degree by treating plasma with MTGase, especially with added cysteine or under HP conditions. However, their WHC is only slightly enhanced for the later.