Investigation of porcine candidate genes for improving marbling score and meat quality traits in commercial swine breeds in Thailand
The objective of this research was to identify candidate gene markers based on their function related to marbling score and meat quality traits in pigs. A total of 313 commercial pigs with five different Duroc (DR) breed fractions: 1 = 100%DR (n = 227), 2 = 50%DR x 50% Large white (LW)(n = 7), 3 = 50%DR x 50%Landrace (LR)(n = 41), 4 = 75%DR x 25%LW (n = 18), and 5 = 50%DR x 25%LW x 25%LR (n = 20) were measured for marbling score (score 3; MB3 and score 6; MB6), Color (L*), % cooking loss and shear force meat characters. The pigs were slaughtered at around 190 days of age, at an average weight of 122 kg. Five candidate genes (LIPE, LEPR, ADRB3, CAPN1, and CAST) were genotyped by using -RFLP. The genetic parameters were estimated with Bayesian analysis via Gibbs sampling and analyzed by estimated breeding value by BLUP. The breed group had an effect on traits, especially marbling traits, percent cooking loss, and shear force. In Duroc purebreds, the marbling scores were significantly higher than in Duroc crossbreds. Al parameters were significantly higher in 50%DR x 50% Large white (LW) compared with the others. Association analysis showed that the AG genotype of the ADRB3 gene had a higher marbling score than the GG genotype (2.22 vs 1.99 for MB3, 2.92 vs 2.49 for MB6; P < 0.05). The lowest estimated breeding values (EBVs) for color (L*)(3.88) and % cooking loss (2.64) were obtained in the CC genotype of the CAPN1 gene. The GG genotype showed lower shear force and EBVs compared to the AG genotype of CAST gene (4.08 vs 4.85 for shear force (P < 0.05) and -0.03 vs 0.05 for EBV’s, P < 0.01). The AG genotype of ADRB3 could be used in marker assisted selection to improve marbling scores. Also, the GG genotype of CAST is the most appropriate for selection for pork tenderness.