Systems biology of piglet maturity
Résumé
In recent decades, improvement of prolificacy and body composition (towards more muscle) was the main goal in pig breeding but the genetic progress has been accompanied by a substantial increase in piglet mortality before weaning. The most critical period is the perinatal period, mostly during the first 24-48 hours after birth. Piglet maturity, defined as the state of full development for survival at birth, is an important determinant of early mortality. However, evaluation of maturity at birth is difficult because of the lack of markers of this complex trait. The objective of our project (PORCINET, ANR09GENM005) is to take advantage of current knowledge about two pig breeds, Large White (LW) pigs selected for prolificacy and body composition and Meishan (MS) pigs being more robust piglets, to identify new markers of this trait. Maturity of several tissues and metabolite profiles of various fluids are analyzed on the fetuses (LW, MS and reciprocal F1) at day 90 or 110 of gestation (birth at day 114). The vitality of the piglets and the maternal behavior are analyzed during the two first weeks after birth. The 1H-NMR metabolic profiles of fetal plasma show that 1) the four genotypes are effectively different and that 2) variation in metabolite profiles amongst fetuses highly increases between day 90 and day 110 of gestation. Physiological parameters (e.g. cortisol, fructose and albumin) differed significantly between genotypes and developmental stages. These data associated with transcriptomic and proteomic data will enrich our understanding of piglet maturity determinism.