Effects of preslaughter muscle exercise on muscle metabolism and meat quality studied in anesthetized pigs of different halothane genotypes.

Abstract

The influence of preslaughter muscle activity was studied on porcine muscle metabolism and meat quality, whereas other stress factors were minimized. Muscle exercise was stimulated by electrical pulses in anesthetized pigs of different halothane genotypes (NN, Nn, nn). A part of the LM and SM was stimulated during the last 15 min of a 45-min period of anesthesia. The contralateral part of each muscle was taken as a non-stimulated control. Antemortem blood and muscle biopsy samples were taken to study the muscle energy metabolism by measuring different metabolites. The same metabolites and certain meat quality characteristics were determined after slaughter. Stimulated muscle exercise led to lower (P < .01) antemortem glycogen and creatine phosphate concentrations and increased (P < .01) lactate and creatine values in pigs of all halothane genotypes. No difference was seen between the three halothane genotypes in the measured glycogen breakdown just before slaughter. Postmortem glycolysis differed between pigs of different halothane genotypes. This resulted in lower (P < .05) glycogen and creatine phosphate values and higher (P < .05) lactate and creatine concentrations for nn pigs than for NN pigs, with intermediate metabolite concentrations for Nn pigs. Water-holding capacity was lower (P < .05) in exercised muscles of NN and Nn pigs than in the muscles of controls. Meat color was only lighter (P < .05) after muscle stimulation in NN pigs. The exercise did not deteriorate the already light color and lower water-holding capacity in nn pigs. Muscle pH can already be low at slaughter and is not only the result of an increased postmortem glycolysis. Preslaughter muscle exercise is relatively more important in determining meat quality from NN and Nn pigs.

Regulation of post-mortem glycolysis in ruminant muscle

“…This in contrast to the large body of evidence published for pigs (e.g. Klont and Lambooy 1995;Warriss et al 1995;Channon et al 2000;Støier et al 2001). The general finding across these studies was that stress just before stunning resulted in lower initial muscle pH, higher initial muscle temperature, and a faster rate of pH decline in the first hour after death but similar rates beyond that.…”

The use of simultaneous 1H & 31P magic angle spinning nuclear magnetic resonance measurements to characterize energy metabolism during the conversion of muscle to meat

“…Both PCr and ATP were degraded within the first 2 h post‐mortem. Considering that the animals were sacrificed by an overdose of Nembutal and thereby not exposed to any pre‐slaughter stress, the degradation rates are very fast in comparison with values previously reported in muscles from pigs sacrificed under anaesthesia and therefore not exposed to pre‐slaughter stress (Klont & Lambooy, 1995; Bertram et al. , 2001, 2002b).…”

“…At present, most studies that include lactate determinations within muscle and meat quantify lactate by biochemical analysis of biopsy samples (Fernandez et al. , 1992; Klont & Lambooy, 1995; Schäfer et al. , 2002).…”

Acute stress induced by the preslaughter use of electric prodders causes tougher beef meat

“…This is in contrast with the large body of recent research in pigs (e.g. Klont and Lambooy 1995;Warriss et al 1995;Channon et al 2000;Stoier et al 2001). The general finding across these pig studies was that stress just before stunning resulted in lower initial muscle pH, higher initial muscle temperature and a faster rate of pH decline in the first hour after death, although similar rates were observed beyond that.…”