Bos indicus cattle possess greater basal concentrations of HSP 27 , alpha B-crystallin , and HSP 70 in skeletal muscle in vivo compared with Bos taurus cattle 1

The objectives of the present study were to evaluate the basal concentrations of heat shock proteins (HSP) between Bos indicus and Bos taurus cattle and to determine if HSP basal concentrations change as an animal matures. A total of 40 cattle were used in a 2 x 2 factorial design to evaluate the effects of genotype and age (heifers and mature cows) on basal concentrations of heat shock protein 27 (HSP27), a B-crystallin (Cryab), and heat shock protein 70 (HSP70). Each experimental group of 10 animals was sampled on a separate day over a period of 4 wk during July 2014. A muscle sample was collected from the longissimus thoracis (LT) and concentrations of HSP were quantified using ELISA. There were no significant differences in HSP concentration for the interaction between age and genotype or for age alone. Bos indicus cattle had greater (P < 0.05) basal concentrations of HSP27, Cryab, and HSP70 in the LT than B. taurus cattle. The results of this study show that basal in vivo HSP concentrations differ between B. indicus and B. taurus cattle. However, further studies are needed to investigate the relationship between HSP concentrations and meat tenderness with respect to genotypes to see if HSP concentrations account for at least some variability in tenderness differences.