PHYSIOLOGICAL APPROACHES TO INCREASE THE EFFICIENCY OF PORK PRODUCTION THROUGH IMPROVED NUTRITIONAL AND REPRODUCTIVE COMPETENCE
Location: Reproduction Research
Title: Contributions of the maternal uterine environment and piglet genotype on weaning survivability potential: I. Development of neonatal piglets after reciprocal embryo transfers between Meishan and White crossbred gilts
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 6, 2012
Publication Date: July 1, 2012
Citation: Miles, J.R., Vallet, J.L., Ford, J.J., Freking, B.A., Cushman, R.A., Oliver, W.T., Rempel, L.A. 2012. Contributions of the maternal uterine environment and piglet genotype on weaning survivability potential: I. Development of neonatal piglets after reciprocal embryo transfers between Meishan and White crossbred gilts. Journal of Animal Science. 90(7):2181-2192.
Interpretive Summary: Sow productivity has a significant economic impact on the swine industry and is influenced by a number of factors including preweaning piglet mortality. The greatest susceptibility for preweaning mortality occurs in low birth weight piglets. Despite their overall decreased birth weights, Meishan piglets have lower preweaning mortality rates compared with contemporary Western breeds. This study investigated the contributions of the piglet and maternal genotypes and their interactions on the development of neonatal piglets pertaining to preweaning survival using reciprocal embryo transfer between Meishan and White crossbred gilts. At day 1 of age, there were significant genotypic effects in favor of Meishan piglets compared with White crossbred piglets on stomach content weights, percentage of fat and nitrogen within the body composition, liver, bicep femoris, and longissimus dorsi glycogen concentrations, and serum albumin levels, which illustrate possible mechanisms of improved preweaning survivability in Meishan piglets. The results of this study demonstrate that the Meishan breed serves as a good model for studying preweaning survivability and that focusing on components relating to energy stores, appetite, and activity has the potential to identify factors associated with piglet survival.
In commercial pigs, the greatest susceptibility for preweaning mortality occurs in low birth weight piglets. However, despite their overall decreased birth weight, Meishan (MS) piglets have lower preweaning mortality rates compared with contemporary Western breeds. The objective of the current study was to determine the contributions of the maternal uterine environment, the piglet genotype, and their interaction on the development of neonatal piglets pertaining to preweaning survivability using reciprocal embryo transfer between MS and White crossbred (WC) pigs. Twenty-five successful pregnancies were produced from two farrowing seasons generating litters of maternal uterine environment (ME) by piglet genotype (PG) combinations; MS x MS (n=4 litters), MS x WC (n=7 litters), WC x MS (n=7 litters), and WC x MS (n=7 litters). At approximately 24 h of age (d 1), piglets (n=173) were weighed and a blood sample was taken. Hematocrit, hemoglobin, glucose, plasma urea nitrogen, albumin, NEFA, lactate, and cortisol were measured in all blood samples. In addition, representative piglets (n=46) from each litter were harvested and body measurements (i.e., organ weights, tissue glycogen content, and body composition) were determined. Piglet data were analyzed by analysis of variance using MIXED model procedures. Both ME (P<0.001) and PG (P<0.01) had significant effects on piglet weight illustrating piglets gestated in WC gilts were heavier than piglets gestated in MS gilts and WC piglets were heavier than MS piglets. Serum albumin levels were increased (P<0.05) in MS piglets compared with WC piglets, indicating greater liver maturity. Significant ME-by-PG interactions were observed for hematocrit and hemoglobin in which the greatest levels were observed in MS piglets gestated in MS and WC gilts and the lowest levels were observed in WC piglets gestated in WC gilts, demonstrating increased oxygen carrying capability. The percentage of fat and nitrogen as well as the gross energy of the body were greater (P<0.05) in MS piglets, indicating greater energy stores. Liver, bicep femoris, and longissimus dorsi glycogen concentrations were greater (P<0.01) in WC piglets compared with MS piglets, suggesting enhanced glycogen metabolism in MS piglets. This study demonstrated that the MS breed serves as a good model for studying preweaning survivability and components relating to energy stores and glycogen metabolism potentially influences piglet survival.