Glutathione peroxidase activity, tissue and soluble selenium content in beef and pork in relation to meat ageing and pig RN phenotype

Since glutathione peroxidase (GSHPx) may be important for meat quality, its activity was examined in relation to animal species (beef and pork), muscle type (oxidative and glycolytic), selenium content, meat ageing and RN phenotype in Hampshire crossbred pigs. The GSHPx activity in bovine M. Longissimus dorsi [LD; 1.9 (0.4) U/g, mean (S.D.)] was significantly higher (P<0.001) than in M. Psoas major [PM; 1.5 (0.5) U/g] and the activities in the two muscles were correlated (r=0.66; P<0.001). Pork LD had a several fold lower GSHPx activity [0.4 (0.2) U/g] than bovine muscles but, in contrast, a somewhat higher content of selenium [113 (15) ng/g] than bovine LD [106 (12) ng/g] and PM [95 (17) ng/g]. The proportion of soluble selenium in bovine LD (72%) tended to be higher than that in bovine PM (64%), and it was significantly lower in pork LD (52%). Significant correlations between GSHPx activity and soluble selenium were obtained in both beef and pork. Thus, GSHPx activity varied among single animals, with species and muscle type, whereas meat ageing and pig RN phenotype had no effect.