Thermal manipulation during broiler chicken embryogenesis: Effect on mRNA expressions of Hsp108, Hsp70, Hsp47 and Hsf-3 during subsequent post-hatch thermal challenge

• During TC, the Tb of TM chicks was significantly lower than those of the controls.
• TM enhances the Hsp108 and Hsp70, Hsp47 and Hsf-3 mRNA expression in post-hatch chicks.
• Higher Hsps mRNA expressions were detected in the muscle and heart during TC.
• The magnitude of mRNA expressions was initial TM duration and tissue-dependent.

Effects of thermal manipulation during broiler chicken embryonic days 12–18 on body temperature (Tb) and mRNA expressions of Hsp108, Hsp70, Hsp47 and Hsf-3 in muscle, heart and brain tissues during subsequent thermal challenge (TC) were investigated. Fertile chicken eggs were divided randomly into four groups (n = 375): eggs in the control group were maintained at 37.8 °C and 56% (RH). Eggs in TM1 group were subjected to TM at 39 °C for 9 h during ED 12–18. Eggs in the TM2 and TM3 groups were subjected to the same protocol of TM1 except for increasing the period of exposure to 12 h and 18 h, respectively. During TC (43 °C for 6 h) at days 10 and 28, Tb of TM chicks was significantly lower compared to controls. Furthermore, significant changes in mRNA expressions of Hsp108, Hsp70 and Hsp47 in muscle, heart and brain tissues were observed.