THE EFFECT OF SKELETAL-MUSCLE RYANODINE RECEPTOR GENOTYPE ON PIG PERFORMANCE AND CARCASS QUALITY TRAITS

Six different breed groups (Yorkshire (Y), Pietrain (P), a Pietrain derivative breed Near Pietrain (NP), and crosses NP X P, P X NP and F-2) were tested for breed, skeltal muscle ryr1 genotype (hal gene), and sex effects on growth, performance and carcass traits. Within the C/C (homozygous normal for the hal gene) or T/T (homozygous recessive for the hal gene) ryr1 genotypes there were significant differences among breed groups in a number of performance and carcass quality traits. In contrast, the performance and carcass quality traits of the C/T (heterozygous for the hal gene) ryr1 genotype-containing breed groups were similar. In the four breeds containing C/T and T/T ryr1 genotypes, the additional copy of the ryr1 T allele had a significantly positive effect on all measures of amount of lean meat with a negative effect on all meat quality scores (P < 0.001). Notably, the C/C and T/T ryr1 genotypes in the NP and F-2 breed groups differed significantly in all measures of amount of fat and lean; the C/T genotype was intermediate to the C/C and T/T genotypes in all traits with the C allele exhibiting partial dominance for these measures. It is concluded that within breed groups of similar genetic background, the ryr1 genotype has positive effects on al measures of the amount of fat and lean, with associated negative effects on meat quality. The availability of the DNA-based test to identify the ryr1 genotype allows pig breeders to take advantage of the beneficial traits or to eliminate the deleterious traits associated with this gene from their populations.