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 de rivative 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 s ex effects on growth, performance and carcass traits. Within the C/C ( homozygous normal for the hal gene) or T/T (homozygous recessive for t he hal gene) ryr1 genotypes there were significant differences among b reed groups in a number of performance and carcass quality traits. In contrast, the performance and carcass quality traits of the C/T (heter ozygous for the hal gene) ryr1 genotype-containing breed groups were s imilar. In the four breeds containing C/T and T/T ryr1 genotypes, the additional copy of the ryr1 T allele had a significantly positive effe ct on all measures of amount of lean meat with a negative effect on al l meat quality scores (P < 0.001). Notably, the C/C and T/T ryr1 genot ypes in the NP and F-2 breed groups differed significantly in all meas ures of amount of fat and lean; the C/T genotype was intermediate to t he C/C and T/T genotypes in all traits with the C allele exhibiting pa rtial dominance for these measures. It is concluded that within breed groups of similar genetic background, the ryr1 genotype has positive e ffects on al measures of the amount of fat and lean, with associated n egative effects on meat quality. The availability of the DNA-based tes t to identify the ryr1 genotype allows pig breeders to take advantage of the beneficial traits or to eliminate the deleterious traits associ ated with this gene from their populations.