The effect of experimental stress on sarcoplasmic reticulum Ca 2+ transport and meat quality in pig muscle

Abstract

Stress before slaughter affects the meat quality of pigs and a disorder in the Ca 2+ transport of the sarcoplasmic reticulum (SR) results in inferior meat quality. The object of this work was to determine the impact of stress on SR Ca 2+ transport in pig muscle in animals with no mutation in the Ca 2+ release channel. At about 80 kg live weight, pigs were stressed either by running for 4 min ( n=9) or by a 5 min application of a nose snare ( n=7). Immediately before and after the application of the stress, as well as 4 h after the stress, biopsy samples of the longissimus muscle were taken and the Ca 2+ uptake of the homogenised muscle samples determined. The nose snare stress reduced the rate of Ca 2+ uptake by 9% ( P=0.02) and running by 18% ( P=0.06). Uptake in samples taken 4 h after the stress was at initial levels. The pigs were slaughtered at an average live weight of 109 kg. Half the pigs were stressed just before slaughter for 5 min by the use of a nose snare. Immediately after exsanguination longissimus muscle samples were taken, Ca 2+ uptake measured, and later standard meat quality parameters were determined. Although the stress reduced the Ca 2+ uptake rate (61.3 vs. 46.4 nM/min per mg protein for control and stressed pigs; P=0.04), the meat quality was not significantly affected.