Effect of swine stress gene on quality and quantity of carcass

The swine stress gene (hal gene) in recessive homozygosis (nn) is associated with the occurrence of the Porcine Stress Syndrome (PSS) and with the occurrence of pale, soft and exudative pork (PSE). In heterozygosis (Nit) it is related to low quality of carcass, but higher carcass weight. This study has characterized the genotype of hal gene by DNA-testing. obtained by alkaline extraction from a single hair root, in a sample of 160 swines. These animals were slaughtered and carcass traits for each animal were measured. Among the 160 animals, 82 (52.58%) were identified as NN, 67 (41.80%) as Nit, and 9 (5.62%) as nn. Variation in carcass traits across genotypes was evaluated by analysis of variance, using SAS. The NN, Nit and tin animals did not differ for: hot carcass weight, backfat thickness, muscle depth, lean meat percentage, and longissimus dorsi muscle color. However, variation in carcass color was lower for NN (40.82%) than for Nit (49.77%) and nn (53.83%) animals. These results indicate that the presence of hat gene in heterozygosis or recessive homozigosis was not associated with better carcass weight and the utilization of these animals may lead to lower carcass quality. Therefore, the intentional use of heterozygous and recessive homozygous animals should not be encouraged.