The effect of skeletal muscle ryanodine receptor genotype on pig performance and carcass quality traits

Six different breed groups (Yorkshire (Y), Pietrain (P), a Pietmin derivative breed Near Pietrain (NP), and crosses NP × P, P × NP and F₂) were tested for breed, skeltal muscle ryrl 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) ryrl 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) ryrl genotype-containing breed groups were similar. In the four breeds containing C/T and T/T ryrl genotypes, the additional copy of the ryrl 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 ryrl genotypes in the NP and F₂ 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 ryrl genotype has positive effects on all 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 ryrl genotype allows pig breeders to take advantage of the beneficial traits or to eliminate the deleterious traits associated with this gene from their populations.