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Abstract: One factor affecting meat quality is pre-slaughter stress. We investigated the effects of exercise stress on drip loss and toughness in relation to resting times of 0, 1 or 3h following exercise on a treadmill. This exercise stress was regarded as combined physical and physiological stress. Exercise stress increased the muscle temperature, reduced the creatine phosphate, ATP and glycogen content of pigs slaughtered immediately after stress exposure. These conditions lead to a reduced pH early post mortem and an increased drip loss, while only 1h of rest after exercise stress normalised these effects. However, an overshooting effect was noted when pigs were rested for 1–3h before slaughter, emphasising the importance of critical control of the resting period when studying exercise stress-induced effects on meat quality. Furthermore, meat from exercise stressed pigs, irrespective of resting, had increased toughness compared to controls, indicating that the toughness was not related to drip loss in meat from exercise stressed pigs. [Copyright &y& Elsevier]

ABSTRACT In commercial production, chickens are subjected to feed withdrawal prior to slaughter and exposed to stress during transport and handling of the animals at the slaughterhouse; this causes plasma glucose and glycogen stores in liver and muscle to decrease, which has a negative impact on meat quality. The aim of the present study was to investigate how supplementation of the energy complements creatine and pyruvate during the fasting period would affect postmortem pH decrease, water-holding capacity, and color of the meat. Female Ross 208 broilers were supplemented with glucose combined with either pyruvate or creatine via the drinking water for 18 or 42 h prior to slaughter, i.e., before and throughout the fasting period. Chickens were slaughtered at 42 or 43 d of age. Temperature and pH were measured at 1, 10, 30, and 45 min and 1, 2, 4, 8, and 12 h postmortem. The results showed that the pyruvate and glucose supplementation increased the pH at 45 min postmortem by 0.25 units and decreased drip loss of musculus pectoralis major (PM) by 50 to 65% in chickens supplemented for 42 h. The creatine and glucose supplementation reduced pH at 3 and 4 h postmortem by 0.32 to 0.42 units, increased the lightness (L*) by 2.3 to 5.6 units, and increased drip loss by 51 to 137% in the PM of chickens supplemented for 18 and 42 h. Pyruvate and glucose supplementation thus appear beneficial but whether this is concomitant with an overall improvement in meat quality remains to be determined. [ABSTRACT FROM AUTHOR]

Abstract: Nuclear magnetic resonance (NMR)-based metabonomics was applied to investigate the effects of pre-slaughter exercise stress on the plasma metabolite profile at time of slaughter. The study included a total of 40 slaughter pigs, which were exposed to one of the following treatments: No pre-slaughter stress (control treatment), pre-slaughter exercise on a treadmill and subsequently 0, 1, or 3h rest prior to slaughter. NMR-based metabonomics revealed a clear difference in the plasma metabolite profile at time of slaughter between control pigs and pigs exercised without rest, which mainly could be ascribed to increased plasma lactate due to exercise. A resting period of 1 or 3h prior to slaughter reversed the stress-induced perturbations in the plasma metabolite profile. The plasma metabolite profile at time of slaughter was highly correlated with muscle temperature 1min post-mortem, and a correlation to WHC was also demonstrated. Lactate was found to be the metabolite of importance for the association between the plasma metabolome and pH, temperature and WHC. [Copyright &y& Elsevier]