EFFECT OF DANTROLENE TREATMENT ON MUSCLE METABOLISM AND MEAT QUALITY OF ANESTHETIZED PIGS OF DIFFERENT HALOTHANE GENOTYPES

Muscle metabolism was studied in pigs of different halothane genotypes by taking blood and muscle biopsy samples during a 45-min preslaughte r period of anesthesia. Dantrolene was administered to half the pigs o f each genotype to investigate whether possible differences in muscle metabolism could be explained by differences in resting myoplasmic cal cium concentrations. Dantrolene influenced muscle metabolism of all ha lothane genotypes to the same extent, leading to higher (P < .05) glyc ogen and creatine phosphate concentrations and lower (P < .05) lactate and creatine concentrations. Dantrolene could not reduce the small bu t significant (P < .05) differences observed in resting muscle metabol ism between the genotypes, and halothane-positive pigs had lower (P < .05) glycogen and creatine phosphate contents. Postmortem muscle metab olism showed differences (P < .05) between the three halothane genotyp es, with the highest rate of glycolysis in halothane-positive pigs. Da ntrolene resulted in a significantly slower (P < .05) glycogen and cre atine-P breakdown, which led to a less rapid (P < .05) accumulation of lactate and creatine in both muscles. Meat quality characteristics di ffered between the halothane genotypes but no PSE meat was detected. D antrolene administration resulted in an elevation (P < .05) of the pH in the longissimus lumborum and in lower (P; < .05) rigor values of th e semimembranosus, both measured at 45 min after slaughter. Water-hold ing capacity was higher (P < .05) and Hunter L-values lower (P < .05) in dantrolene-treated pigs than in the control animals. It was conclu ded that due to the method of anesthesia there were only small differe nces in muscle metabolism at slaughter between pigs differing in their genetic susceptibility to stress that were not reduced by dantrolene administration, and in practice reducing the amount of preslaughter st ress might be more important for NN- and Nn-pigs than for nn-pigs.