Summer season induced heat stress associated changes on meat production and quality characteristics, myostatin and HSP70 gene expression patterns in indigenous goat

The study was conducted to assess the effect of heat stress on the meat production and quality variables in indigenous Malabari breed goats. The study was conducted during 45 days using twelve 10 months to one year old Malabari goats. The goats were randomly allocated into two groups: MC (n = 6; Malabari control) and MHS (n = 6; Malabari Heat stress). The MC group animals were housed inside the shed without exposure to outside environment while the MHS group animals were exposed to summer heat stress by keeping them outside the shed from 10:00 h to 16:00 h. At the end of the study, animals were slaughtered and their meat characteristics were assessed. The findings from the study revealed that heat stress caused significant reduction in live weight (P < 0.05), pre-slaughter weight (P < 0.01), hot carcass weight (P < 0.05), loin eye area (LEA) (P < 0.01), and fat score (P < 0.01). Fore saddle is the only primal cut which was significantly (P < 0.05) lower in weight in MHS as compared to MC group. Further, meat quality variables such as ultimate meat pH, water holding capacity (WHC) and shear force significantly (P < 0.01) increased during heat stress. Among the sensory characteristics, appearance (P < 0.01) and flavour (P < 0.05) reduced significantly in MHS group. However, plasma leptin level was significantly (P < 0.01) higher in MHS group. In addition, the skeletal muscle myostatin gene expression pattern was significantly (P < 0.05) lower while HSP70 gene expression was significantly (P < 0.05) higher in MHS as compared to MC group. Thus, it may be concluded from the study that indigenous Malabari goats possessed the inherent ability to maintain meat production by overcoming the adverse effects of heat stress. However, the severity of heat stress was reflected on the meat quality variables in this breed.