The Effects of Porcine Peroxisome Proliferator-Activated Receptorg (PPARg) in Four Commercial Breeds of Swine
Rebecca S. Emnett1, Eli Grindflek2, Max F. Rothschild3, Steven J. Moeller1, David L. Meeker1 and Keith M. Irvin1
1The Ohio State University, Columbus, Ohio 2Agricultural University of Norway, Ås, Norway and 3Iowa State University, Ames, Iowa
Currently the improvement of meat quality is one of the top priorities of the swine industry. Several environmental and genetic factors contribute to the ultimate quality of both fresh and processed pork. The objective of this study was to investigate the effects of a meat quality candidate gene, Peroxisome Proliferator-Activated Receptor g (PPARg), in four breeds of swine. PPARg is a transcription factor involved in regulating expression of genes associated with lipid metabolism. Previous results show PPARg involvement in adipocyte differentiation in several species and therefore it may be associated with intramuscular fat. However, the effects of this gene on meat quality in the pig have yet to be determined. Berkshire (n=160), Hampshire (n= 142), Duroc (n= 74) and Landrace (n=54) pigs, that had been highly characterized for production, carcass and meat sensory traits in the 1998 National Barrow Show Progeny Test were genotyped based on PCR-RFLP procedures. Statistical analyses were completed for the entire population (n= 430) and for each breed separately using the GLM procedure in SAS with fixed effects of sire, sex, genotype and off test date. Total population analysis revealed effects (p<.05) of PPARg on cooking loss, Instron tenderness and juiciness score. Allelic frequencies were similar among all breeds except Berkshire. Individual breed analysis also indicated significant (p<.05) PPARg effects on Instron tenderness (Landrace), backfat (Duroc and Landrace), cooking loss (Hampshire), and flavor score (Berkshire). These results, while promising, warrant larger scale investigation to determine the potential use of PPARg in selection for meat quality traits in swine.
Key Words: Meat Quality, Molecular Marker, PPARg