Seasonal effects on Ca(2+) transport of sarcoplasmic reticulum and on meat quality of pigs with different malignant hyperthermia status.

The intracellular Ca(2+) concentration is mainly regulated by the sarcoplasmic reticulum (SR). A disturbed regulation leads to an increased metabolism and ultimately to inferior meat quality. In this study, pigs with normal and mutated calcium release channels (referred to as MHR and MHS, respectively) were used. One batch of pigs was slaughtered in winter months and another in summer months. The intention was to elucidate the impact of season on the Ca(2+) transport of SR and on meat quality in dependence of the MH-status. The results show an impact of MH-status and of season on the meat quality with inferior values in summer months, and in MHS pigs. Immediately after slaughter the rate of Ca(2+) sequestration of the SR with biochemically closed and with opened calcium release channels (CRC) was not different between experimental groups. However, with basic CRC (not biochemically manipulated) the Ca(2+) uptake rate of MHR muscle of summer pigs was significantly reduced and at the level of that of MHS pigs. The results indicate an impact of summer season on the ability of SR to regulate Ca(2+) concentration properly even in pigs with a normal CRC. This disturbed Ca(2+) regulation is correlated with diminished meat quality.