MUSCLE METABOLIC TRAITS, POST-MORTEM PH-DECLINE AND MEAT QUALITY IN PIGS SUBJECTED TO REGULAR PHYSICAL-TRAINING AND SPONTANEOUS ACTIVITY

Ninety-six female and male pigs were assigned to one of three treatmen ts, 'confined' (C), 'trained' (T) or 'free' (F) allowing for different levels of physical activity during the growth interval from 30 to 100 kg. Treatment C consisted of individual housing in pens of 2.5 m(2); treatment T of individual housing and regular treadmill training and t reatment F of housing in pens of 36 m(2) (40 pigs/pen). In m. biceps f emoris (BF), the activity of lactate dehydrogenase (LDH) was decreased between 9 and 12% by training (treatment T vs C). Likewise, in BF fro m female pigs, training increased the activity of citrate synthase (CS ) and of 3-OH-acyl-CoA-dehydrogenase (HAD) by 18 and 21%, respectively . Spontaneous activity (treatment F) reduced the activity of LDH for f ive muscles between 10 and 16% when compared with treatment C. Around the time of slaughter, glycogenolysis of BF was less for treatment F ( 6-17%) than for C and T (33-38%). Moreover, in BF from female pigs in treatment F, the initial but not the ultimate pH was increased when co mpared with treatment C. In comparison to C and T, treatment F improve d juiciness in BF from male pigs and increased the amount of salt solu ble protein in m. longissimus dorsi. (C) 1997 Elsevier Science Ltd.