It is well known that accelerated/compensatory growth may occur in pigs after a
period of feed restriction. However, very few data are available on the possible consequences of accelerated
growth on muscle protein-turnover in pigs (growth rate of muscle, nucleic acid
contents, proteolytic enzyme activities). The content of DNA and RNA, as well as
their mutual proportions, influences the capacity of muscle for protein synthesis.
Similarly, the activity of proteolytic enzymes (e.g. m- and m-calpain) influences
muscle growth (Goll et al. 1998). The majority of studies on this topic investigated
final effects, mainly at slaughter weight (e.g. Kristensen et al. 2002; Oksbjerg et al.
2002; Therkildsen et al. 2002, 2004). In this study, these effects are examined in
growing pigs from 25–105 kg bodyweight (BW) at several stages of bodyweight. Based on the results it can be concluded that limitation of protein and energy intake during early growth of pigs does not strongly influence
daily muscle gain and protein deposition in the LD muscle. Similarly, re-introducing
adequate feeding did not influence these features. However, protein/energy
restriction decreases DNA concentration in the LD muscle, and during the following
recovery period the DNA concentration tends towards its normal content.
Moreover, higher rate of gain of total content of DNA in the LD muscle of
temporarily restricted pigs do not cause increased protein deposition in the muscle. As far as the activity of m-calpain is concerned, our results do not prove that it could
be increased in recovering pigs.