Late Fetal Blood Transcriptomic Approach To Get Insight Into Biology Related To Birth Survival

In recent decades, improvement of prolificacy and body composition has been accompanied by a substantial increase in the mortality of piglets before weaning. The most critical period is the perinatal period, mostly during the first 24-48 hours following birth. The maturity of piglets, defined as the state of full development for survival at birth, is an important determinant of early mortality. The objective of our project 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. 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). Here we presented the transcriptomic analysis done on total blood samples (N=63). We did two different statistical analyses, a supervised one to reveal differential pathways for the interaction between gestational stages and genotypes and an unsupervised analysis (hclust and differential analyses) to identify potential predictors of a lesser maturity at birth. All p-values were adjusted with a Bonferroni correction < 1%. The 265 genes differential for the interaction (Bonferroni 1%) in blood samples revealed many genes for mitochondrial ATP synthesis, transcriptional regulation, and response to hypoxia (overexpressed in LW at day 110 of gestation)

Exploring transcriptomic diversity in muscle revealed that cellular signaling pathways mainly differentiate five Western porcine breeds

Among transcriptomic studies, those comparing species or populations can increase our understanding of the impact of the evolutionary forces on the differentiation of populations. A particular situation is the one of short evolution time with breeds of a domesticated species that underwent strong selective pressures. In this study, the gene expression diversity across five pig breeds has been explored in muscle. Samples came from: 24 Duroc, 33 Landrace, 41 Large White dam line, 10 Large White sire line and 39 Piétrain. From these animals, 147 muscle samples obtained at slaughter were analyzed using the porcine Agilent 44 K v1 microarray. A total of 12,358 genes were identified as expressed in muscle after normalization and 1,703 genes were declared differential for at least one breed (FDR < 0.001). The functional analysis highlighted that gene expression diversity is mainly linked to cellular signaling pathways such as the PI3K (phosphoinositide 3-kinase) pathway. The PI3K pathway is known to be involved in the control of development of the skeletal muscle mass by affecting extracellular matrix - receptor interactions, regulation of actin cytoskeleton pathways and some metabolic functions. This study also highlighted 228 spots (171 unique genes) that differentiate the breeds from each other. A common subgroup of 15 genes selected by three statistical methods was able to differentiate Duroc, Large White and Piétrain breeds. This study on transcriptomic differentiation across Western pig breeds highlighted a global picture: mainly signaling pathways were affected. This result is consistent with the selection objective of increasing muscle mass. These transcriptional changes may indicate selection pressure or simply breed differences which may be driven by human selection. Further work aiming at comparing genetic and transcriptomic diversities would further increase our understanding of the consequences of human impact on livestock species

Des approches multi-omiques pour caractériser la fin du développement foetal et mieux comprendre le déterminisme de la maturité à la naissance en lien avec la survie néonatale

Session : Génétique et qualitéNational audienceSelection for high prolificacy and lean growth rate in swine has been associated with a substantial increase in piglet mortality. The first 24‐48 hours after birth represent a critical period for survival. A major determinant for early survival is piglet maturity at birth which relies greatly on the process of tissue maturation during the last month of gestation. The objective of this study was to compare the progenies from Large White (LW) and Meishan (MS) breeds which differ for piglet survival and neonatal mortality.This project proposes multi‐disciplinary and multi‐omic approaches to identify the molecular and genetic basis related to maturity and perinatal survival. The metabolome was analyzed on plasma, urine, and amniotic liquid on 612 fetuses: it displayed higher heterogeneity at the end of gestation. The transcriptome of adrenal glands, muscle, liver, subcutaneous adipose tissue, and small intestine and the proteome of muscle and adipose subcutaneous tissue were analyzed on 64 fetuses. The first analyses identified the biological processes involved in development and maturity, and key genes that may explain the differences observed between LW and MS

Additional file 1: of Exploring transcriptomic diversity in muscle revealed that cellular signaling pathways mainly differentiate five Western porcine breeds

1,859 genes were identified to be differentially expressed between five breeds according to statistical analysis. 1,703 were differentially expressed with a linear mixed model (FDR < 0.1 %, column Pval. Breed.effect. BHcorrection) and 1,655 are declared differentially expressed between breeds with a pairwise analysis (FDR < 0.1 %; FDR < 5 % only for LWM compared to LWF, columns E to Y). This additional file corresponds to the analysis not restricted to autosomes. DU: Duroc; LWF: Large White dam line; LWM: Large White sire line; LR: Landrace; PI: Piétrain. (XLSX 515 kb

El adelantado : Periódico de Intereses Morales y Materiales, Ciencias, Literatura y Artes: Año XX Número 1255 - 1899 marzo 16

Copia digital. Madrid : Ministerio de Cultura. Subdirección General de Coordinación Bibliotecaria, 200