The effect of dietary magnesium oxide supplementation on postmortem 31P NMR spectroscopy parameters, rate of Ca2+ uptake and ATPase activity of M-longissimus dorsi and meat quality of heterozygous and normal on malignant hyperthermia pigs

Twenty four crossbred (Large White, White Meaty, Pietrain, Hampshire) pigs were tested by DNA probe for a mutation on the ryanodine receptor RYR1 (malignant hyperthermia-MH). An equal number of pigs heterozygote (monomutant-MON) and normal on MH (nonmutant-NON) were used in the experiment. The pigs were fed finisher feed (control group) or finisher feed supplemented with magnesium (3.6 g MgO per pig per day; MgO group) for 5 days prior to slaughter. Pigs fed the diet supplemented with MgO had higher plasma Mg concentrations. Phosphorus nuclear magnetic resonance (P-31 NMR) measurements on postmortem (15 min) muscle samples (longissimus muscle) showed the highest phosphocreatine levels in normal pigs fed MgO (P < 0.05). The MgO supplementation caused increased Ca2+ uptake and Ca2+ ATPase activity only in normal (NON) pigs. ATPase activity was lowest (P < 0.05) in heterozygote control pigs. Pigs fed MgO supplemented diet had higher pH (45 min postmortem). A significant lower pH (P < 0.05) was obtained in heterozygous (MON) control pigs. Also pigs fed with MgO had lower percentage of drip losses and significant differences (P < 0.05) were obtained between heterozygous (MON) pigs. The results indicate that dietary MgO supplementation can improve parameters of muscle energetic metabolism, Ca2+ uptake and meat quality (pH, drip loss).(C) 2003 Elsevier Ltd. All rights reserved.