Abstract
BackgroundLimited data are available about the kinetics of mRNA expressions of Heat shock proteins (HSPs) and heat shock factors (HSFs) in the thermally manipulated (TM) broiler chicks during acute heat stress. Therefore, this study aimed to investigate effects of thermal manipulation (TM) of broiler chicken during embryonic days (ED) 12-18 on the basal and dynamics mRNA expression of heat shock proteins (HSP108 and HSP90) and heat shock factors (HSF-1 and HSF-2) in the muscle tissue during late embryogenesis, first week of life and during heat stress (HS) on post-hatch days 14 and 28. One thousand and five hundred fertile Ross 315 broiler eggs were randomly allocated to five groups: control group (37.8 degrees C), TM1 (38.5 degrees C for 18h), TM2 (39 degrees C for 18h), TM3 (39.5 degrees C for 18h) and TM4 (40 degrees C for 18h). Chicks from each treatment group were then randomly sub-divided into two further treatment groups, naive and thermal challenged (TC). On post-hatch days 14 and 28, thirty chicks from each TC group were subjected to heat stress (41 degrees C for 6h), while naive chicks of each group (n=30) were kept under regular conditions. The response of chicks to heat stress was investigated by evaluating the change in mRNA expressions of HSP108, HSP90, HSF-1 and HSF-2 in muscle tissue after 1, 3 and 5h of heat stress.ResultsWhen compared to the control group, TM resulted in significant increases in the basal mRNA expression of HSPs and HSFs during embryogenesis and altered their dynamic expressions in the muscle tissue after heat stress on post-hatch days 14 and 28.Conclusionthe current study indicated short- and long-term enhancement of HSPs and HSFs gene expression which was associated with acquisition of improved thermotolerance in thermally manipulated chicks.