Transcriptome profiling to predict piglet early development and vitality from umbilical cord blood
Résumé
The objective was to identify molecular predictors of piglet level of vitality and development at birth. The parental genetic influences on early-life traits were analyzed with comparison of purebred and crossbred piglets born in the same litter, from Meishan (MS) or Large White (LW) sows. We used mixed semen from the 2 breeds to inseminate first parity sows. Phenotypes included growth, body mass indexes and indicators of vitality, i.e., reactivity scores, with repeated measurements. The study included litters from 8 LW sows and 9 MS sows producing a total of 245 piglets. Blood samples were collected at birth from the umbilical cord in PAXgene Blood RNA Tube. Transcriptome analyses were carried out with the Agilent 60K microarray on 3 to 8 newborn piglets from each litter, resulting in a total of 21 LWLW, 19 MSLW, 22 LWMS and 19 MSMS samples. Statistical analyses were carried out with restricted maximum likelihood methodology, differential and discriminant analyses. Crossbred piglets from LW sows had a higher early growth than their purebred counterparts (P<0.01). No significant differences were observed between purebreds and crossbreds born from MS sows. Among the 2,247 differentially expressed genes that were identified with a significance threshold of 1%, 1962 genes were expressed differentially according to genotype. Co-variation between phenotypes and whole blood transcriptome profiling were investigated by multivariate approaches. Clusters of genes that co-vary with early growth were identified, in favour of crossbreds from LW sows. We are refining the analyses. Samples from LW piglets dead in early-life were added to the data base. The identification of genes biomarkers for early-life development and vitality is in progress and confirmed by RT-qPCR.