Effects of Taurine Supplementation on Heat Shock Protein 70 and In Vitro Protein Syntheses in Liver of Broiler Chicks under Chronic Heat Stress

Abstract

This study was conducted to investigate the effect of taurine supplementation on heat shock protein 70 and in vitro protein turnover in broiler chicks under chronic heat stress. Chicks were allocated into 3 groups of 10 birds per group; the control group was maintained at a temperature of 24℃ without taurine (CO group), the heat-stressed group maintained at a temperature of 34℃ without taurine (HO group), and heat-stressed group maintained at a temperature of 34℃ with taurine (HT group). The final body and liver weights of broilers in the HO and HT groups were significantly lower than those of broilers in the CO group (P<0.05). However, these parameters of the broilers in the HT group were significantly higher than those of broilers in the HO group (P<0.05). The heat shock protein 70 (hsp70) concentration in the liver of broilers in the HO group was significantly higher than that of broilers in the CO and HT groups, but the hsp70 concentration in the liver of broilers in the HT group was not different from that of broilers in the CO group. Liver homogenates of 21 day-old broilers were incubated at temperatures of 37°C and 45℃ to prove the effect of high temperature and taurine on total protein syntheses. Neither high temperature nor taurine supplementation affected protein syntheses in liver homogenates of the broilers. However, the more the temperature increased, the more the degradation rates of cytoplasmic protein in liver homogenates increased; however, taurine supplementation had no effects on the protein syntheses in the liver of the broiler. It is possible that taurine indirectly affected protein turnover via various physiological mechanisms.(Key words: broiler chicks, heat stress, taurine, protein syntheses) † To whom correspondence should be addressed : ksshim@jbnu.ac.kr 서 론 최근 기후 변화로 인한 폭염이 극심하게 발생하였으며, 이 에 따라 가축에게 미치는 영향에 대한 관심이 지속적으로 높 아지고 있다 (Hoffmann, 2010). 특히, 닭은 땀샘이 없어 고온 환경에서 체온 조절이 어렵기 때문에 사육 온도는 가금 산업 에서 매우 중요한 환경적 요인이다 (Yu and Bao, 2008).