Protein, nucleic acid content and activity of μ- and m-calpain in the longissimus dorsi muscle as affected by protein and energy restriction during early growth of pigs

Abstract

The study was conducted to determine the changes in growth rate, protein deposition, concentration of nucleic acids, and activity of calpain enzymes in the longissimus dorsi muscle of pigs, which received a low protein and low energy diet from 25–50 kg bodyweight (BW) followed by adequate feeding to 105 kg BW in comparison with pigs fed adequately throughout the study. The muscle of pigs subjected to limitation tended to grow slower and deposit less protein daily (by 25%, p < 0.10), but have a significantly lower DNA concentration (by 13%, p < 0.01). The activity of μ- and m-calpain was also significantly lower compared with control pigs (0.942 vs. 1.92 and 0.246 vs. 0.403 U/g, respectively). After resumption of adequate feeding, the daily gain of muscle and protein deposition did not differ from control pigs. Moreover, at 80 kg and 105 kg BW the DNA and RNA concentration as well as the activity of m-calpain and μ-calpain did not differ between groups.

Keywords:

• pigs
• growth
• DNA
• RNA
• calpain