Influence of Dietary Energy Level on Hepatic70-kDa Heat Shock Protein Expression in Broiler Chickens Submitted to Acute Heat Stress

Abstract

This experiment was carried out to study the effect of dietary energy on the colonic temperature and hepatic Hsp70 content in broiler chicken at room temperature and after heat stress conditions. Broiler chickens were reared up to 51 days of life, and fed diets containing high (HE -13,186 kJ ME/kg) or low (LE -12,139 kJ ME/kg) energy. At 21 and 51 days of age, the colonic temperature was measured at room temperature and liver samples were obtained for Hsp70 quantification by Western blotting analysis. It was also investigated at these ages the time course response of colonic temperature and hepatic Hsp70 level during heat stress (35º C/5 h). The data showed that at early age, at room temperature, colonic temperature or hepatic Hsp70 levels were not affected by dietary energy, but at 51 days of life low energy fed broilers had lower Hsp70 concentration in the liver. During heat stress, the increase in both colonic temperature and hepatic Hsp70 concentration were significantly less in high energy fed birds. The findings of this study suggest that hepatic Hsp70 synthesis is affected by dietary energy, and that broiler chicken fed high-energy diet can change the thermoresistance during acute heat stress.

Keywords

• broiler chicken
• dietary energy level
• heat shock protein
• heat stress