Allely frequency of porcine stress syndrome in Nuevo Leon by PCR-RFLP analysis

Abstract

PORCINE STRESS SYNDROME (PSS), CAUSED BY A POINT MUTATION IN THE GENE CODING FOR THE RYANODINE RECEPTOR (LOCUS RYR-1), IS ONE OF THE PROBLEMS THE PORK INDUSTRY IS FACING TODAY. PSS, ALSO KNOWN AS MALIGNANT HYPERTHERMIA, CAUSES DEATH IN ANIMALS OR LOWER MEAT PRODUCT QUALITY. THESE PROBLEMS ARISE IN THE AFFECTED ANIMALS WHEN THEY ARE UNDER STRESSFUL CONDITIONS, SUCH AS DURING TRANSPORTATION. CURRENTLY, THERE ARE NO DATA ON THE GENE FREQUENCY OF THE CONDITION IN NUEVO LEON ; HOWEVER, ANECDOTAL EVIDENCE POINTS TO A FREQUENCY SIMILAR TO THAT OF COUNTRIES IN WHICH DATA DO EXIST FOR THE LANDRACE, DUROC, LARGE WHITE AND HAMPSHIRE BREEDS. IN THE PRESENT STUDY A MOLECULAR BIOLOGY TECHNIQUE WAS USED TO DETERMINE THE GENOTYPE OF ANIMALS FOR THE SYNDROME, BASED ON THE POLYMERASE CHAIN REACTION AND THE DIGESTION OF ITS PRODUCTS WITH A RESTRICTION ENZYME (PCR-RFLP). A TOTAL OF 77 ANIMALS WERE ANALYZED, OF WHICH 23 PRESENTED THE RECESSIVE ALLLE (29.9%); ACCORDING TO THE GENOTYPE, 26% WERE CARRIERS (N/N). THERE WAS NO SIGNIFICANT DIFFERENCE IN MUTATION FREQUENCY BETWEEN MALES (33.4%) AND FEMALES (26.3%), ALTHOUGH THERE WERE MORE AFFECTED FEMALES THAN MALES (NN). GENOTYPE FREQUENCIES FOUND WERE 0.70 (54/77) FOR THE DOMINANT HOMOZYGOTYE (NN), 2.6 (29/77) FOR THE HETEROZYGOTE (NN) AND 0.04 (3/77) FOR THE RECESSIVE HOMOZYGOTE. FREQUENCIES WERE 0.17 FOR THE RECESSIVE ALLELE (N) AND 0.83 FOR THE DOMINANT ONE (N).