Effect of Calpastatin Gene Polymorphism on Lamb Growth and Muscling

The calpain-calpastatin system plays a key role in skeletal muscle growth and development processes. It is known that calpastatin activity correlates highly with muscle growth rate, which implies that skeletal muscle growth is likely to result from reduced protein degradation due to compromised activity of calpains or substantial increase of calpastatin activity. The objective of the present research was to identify polymorphic forms in intron 12 of the ovine calpastatin gene in sheep of synthetic lines BCP and SCP, followed by determination of the correlation between each polymorphic form of CAST gene and chosen traits characterizing lamb growth and muscling. The present study's results suggest that lambs carrying the "b" and "e" alleles and the "ae" genotype could be preferred when selecting for growth rate. The breeding efforts to obtain substantial increases in sheep muscle mass could focus on animals carrying the "ac" genotype. No statistically significant relationship was observed in any of the analysed cases between values of the traits and the CAST genotype. However, a highly significant effect of the study year on the analysed traits was found. The results should be regarded as preliminary. The research should be continued on a larger group of animals to ensure the adequate number of each genotype. The trends mentioned and discussed above may also serve as an indicator showing the future direction of further studies in this area.