Excess methionine supply during a short period improves technological and sensory pork quality
Résumé
Both meat industries and consumers claim for better pork quality. Production factors including nutritional strategies affect muscle properties before pig slaughtering, which might improve technological and sensory meat quality traits. However, many of those factors deteriorate growth performance, limiting their application in pig production. Methionine (Met) is the second limiting amino acid in pigs, and is an essential component for glutathione (GSH) synthesis, the main non-enzymatic cellular antioxidant. Reduced protein and lipid oxidations during meat storage may limit drip loss and improve the stability of meat color. This study aimed at evaluating whether dietary Met provided in excess might improve pork quality. During the last 14 days before slaughter, crossbred [(LWxLD)xPietrain] pigs were individually fed one (n=15 pigs/diet) of three pelleted finishing diets (13.6% protein, 5.8% fat, 2,488 kcal/kg Net energy, 0.73% Lys) supplemented with 0 (CONT), 5 (Met+) or 10 (Met++) g/kg of OH-Met (HMTBA). Dietary Met content was 0.22% (growth requirement), 0.66% (3X) and 1.1% (5X) in CONT, Met+ and Met++ diets, respectively. After 14 days of feeding, pigs were slaughtered. Growth rate, feed intake and feed conversion ratio were not significantly different between groups. Carcass weight, carcass composition and lean meat content were similar in the 3 groups. In the Longissimus muscle, GSH content was greater (P<0.001) in Met++ pigs than in the two other groups. Ultimate pH in the loin and ham muscles was also higher in Met++ pigs (+0.10 to 0.15 units, P<0.01). Drip losses, meat lightness and hue angle (yellow color) of loin after 7 d storage at 4 °C were the lowest (P<0.10) in Met++ pigs. Technological meat quality index of ham was improved by Met supplementation in a dose-dependent manner (P<0.01). Thus, dietary Met in excess (5X requirement) improves the technological quality and color stability of pork during storage, without any adverse effects on pig performance or carcass traits.