Chemical fat composition of muscles of the indigenous Nigerian pigs as influenced by age and sex

Seven selected muscles of 96 indigenous Nigeria (32 female, 32 castrated male and 32 intact male) pigs aged between birth and 504 days were analysed for chemical fat. Highly significant age effects were observed for the seven muscles. Statistically significant sex differences were observed for all the muscles except semitendinosus. Generally, fat values for muscles of intact male pigs were lower than for the other two sexes. While non-significant sex-age interactions were observed for biceps femoris, semitendinosus, semimembranosous and longissimus dorsi muscles, highly significant effects were observed for psoas major, triceps brachii and infraspinatus. Growth coefficients b derived from log-log regressions of intramuscular fat weight on body weight ranged from an average of 1·088 (R(2) = 0·956) for M. infraspinatus to 1·348 (R(2) = 0·934) for M. biceps femoris and from 0·604 (R(2) = 0·945) to 0·756 (R(2) = 0·941) when related to carcass fat. Average growth coefficients for fore limb muscles were less than for hind limb and spinal column muscles. Fat growth in other depots is reported for comparison with growth of intramuscular fat.