Hsp90, Hsp60 and HSF-1 genes expression in muscle, heart and brain of thermally manipulated broiler chicken

• The Tb of TM chicks was significantly lower than those of the controls during TC.
• TM chicks had a higher T4 and a lower T3 levels compared with the controls during TC.
• TM enhances the Hsp90 and Hsp60 mRNA expression during embryonic and posthatch chicks.
• Higher Hsps mRNA expressions were detected in the muscle and heart during TC.
• The magnitude of mRNA expressions was tissue- and initial TM duration-dependent.

The effect of thermal manipulation (TM) during embryogenesis (ED 12–18) on mRNA expressions of heat shock proteins (Hsp90, Hsp60 and HSF-1) in muscle, heart and brain tissues during thermal challenge (TC) at post-hatching days 10 and 28 was investigated. Fertile chicken eggs were randomly divided into four groups: Control group (37.8 °C), TM1 (39 °C for 9 h), TM2 (39 °C for 12 h) and TM3 (39 °C for 18 h). At days 10 and 28 of age, chicks in TC groups were subjected to thermal challenge (TC) at 43.0 °C for 6 h while naïve chicks were kept under regular conditions. When compared with the control, TM resulted in a significant increase in mRNA levels of Hsp90, Hsp60 and HSF-1in muscle, heart and brain tissues during embryogenesis and during TC at days 10 and 28 post-hatching. These results indicate a long-term enhancement of Hsp90, Hsp60 and HSF-1 gene expressions associated with improved thermotolerance acquisition in thermally manipulated chicks.