A further look at candidate genes for glycolytic potential: association with meat quality and production traits in Italian Large White pigs.

Glycolytic potential (GP) is a measure related to the energy metabolism of the skeletal muscle. This parameter is correlated to several meat quality traits, like pH, meat colour, drip loss and processing yield. Previously, we investigated in pigs tens of candidate genes for GP chosen among those involved in the glycogen metabolism and glycolysis pathways as well as their regulation in skeletal muscle. Polymorphisms identified or analysed in these genes have been screened in a first association study with meat quality traits in commercial pig hybrids. Significant results were obtained for muscle pyruvate kinase (PKM2), muscle phosphoglycerate mutase (PGAM2) and gamma 3 non-catalytic subunit AMP-activated protein kinase (PRKAG3) genes. Here we further investigated these three genes to evaluate their putative effects on meat quality and production traits in pure bred Italian Large White (ILW) pigs. Glycogen and lactate content, GP, pH1 and pH2 were determined on muscle longissimus dorsi of 270 ILW sib tested animals. Estimated breeding values were calculated by ANAS for average daily gain (ADG), back fat thickness and lean content (LC). These animals were genotyped for single nucleotide polymorphisms of the PKM2, PGAM2 and PRKAG3 (T30N, G52S and I199V mutations) genes. Association analysis between genotypes at these loci and the indicated traits was performed using the GLM procedure of SAS. Significant results (P<0.05) were obtained for PKM2 (pH1, GP, ADG, LC) and PRKAG3 I199V (pH1).