H.Y. Chung, M.E. Davis1, and H.C. Hines
The Ohio State University Department of Animal Sciences
Abstract
Relationships of the calpastatin system with calpastatin activity, meat tenderness and carcass traits were examined in 47 purebred Angus bulls from the Eastern Ohio Resource Development Center (EORDC). The bulls were from two lines divergently selected for blood serum insulin-like growth factor-I (IGF-I) concentration. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis at the calpastatin locus. Following selection of PCR primers based on the bovine cDNA sequences, one set of primers was generated from calpastatin domain I (CAST67), and a second set from domain IV (CAST28). Bulls approximately 13 to 15 months of age were slaughtered, and carcass traits, including fat thickness (FAT), longissimus muscle area (LMA), percentage of kidney, pelvic and heart fat (KPH), hot carcass weight (HCW), marbling score (MAR) and quality grade (QUL) were measured. In addition, the activity of calpastatin (CAC), and Warner-Bratzler Shear Force (WBS) were measured. The statistical model for this analysis included fixed effects of calpastatin genotypes, age of dam, IGF-I selection line, and a covariate for age of bull. Genetic polymorphisms among individuals were observed for both domains of the calpastatin locus (AA, AB, and BB). Significant differences among CAST67 genotypes were found for KPH (P < 0.01) and CAC (P < 0.05). Genotypes of CAST28 also influenced KPH (P < 0.01) and CAC (P < 0.05). Least significant differences among CAST67 and CAST28 genotypes were found at the P = 0.05 level for KPH (BB>AB>AA) and CAC (BB>AB>AA). CAC was highly correlated with FAT and MAR (P < 0.05). It may be possible to use calpastatin genotypes classified by PCR-RFLP and SSCP in marker assisted selection programs to improve carcass traits and calpastatin activity.