ARS | Publication request: USE OF TRANSCRIPTIONAL PROFILING TO UNDERSTAND GENETIC MECHANISMS CONTROLLING FEED INTAKE AND EFFICIENCY IN PIGS

Submitted to: International Conference on Animal Genetics
Publication Type: Abstract Only
Publication Acceptance Date: June 30, 2006
Publication Date: August 1, 2006
Citation: Lkhagvadorj, S., Qu, L., Cai, W., Couture, O., Wang, Y., Andrson, L., Dekkers, J., Ettleton, D., Tuggle, C., Barb, C.R., Hausman, G.J., Rekaya, R. 2006. Use of transcriptional profiling to understand genetic mechanisms controlling feed intake and efficiency in pigs [abstract]. 30th International Conference on Animal Genetics. p. C532.

Technical Abstract: Feed is the major variable cost in pork production. Determination of genetic mechanisms that control feed intake (FI) and feed efficiency (FE) remains a major challenge for the improvement of FE and FI. Although feed is associated with production traits such as growth and composition, considerable variation in FE and FI exists independent of these traits. This variability is called residual feed intake (RFI) and has heritability of 15-40% in pigs. In this study, using transcriptional profiling of key tissues, we aimed to identify genetic mechanisms differing between control pigs and pigs that have been under selection for low RFI for three generations. A further aim was to determine the pathways responding to feed restriction within these lines and any line x treatment interactions resulting in gene expression differences. Low RFI pigs (n=4) and control pigs (n=4) were allowed feed ad libitum or were feed restricted to 80% of maintenance for 7 days in a complete 2 x 2 factorial design. Total RNA was isolated from liver and fat tissues from all pigs, and analyzed using hybridization to the 24,123 probe set Affymetrix Porcine GenechipTM. A mixed linear model was fit to each tissue and each gene using SAS Proc Mixed. Preliminary results indicate that 2,809 genes in fat (p<0.04, q<0.2; among which 1,219 genes with q<0.15) and 61 genes in liver (p<0.001, q<0.2) showed differential expression in response to feed restriction. Also, 1,247 genes (p<0.02, q<0.2; among which 344 genes with q<0.15) showed differential expression between low RFI and control pigs and 38 genes (p<0.001, q<0.2) showed a line x feed interaction in liver. Based on these results, candidate genes will be selected as a first step in hypothesis formation. Along with blood hormone assays, confirmation of expression of candidate genes will be performed to determine potential pathways that control FI and FE in pigs.