Examination the effect of post-hatch heat-treatment and heat-stress in Transylvanian Naked Neck chicken

Abstract

Background One of the most critical global problem nowadays is the increased environmental temperature. Agriculture is very susceptible to this adverse effect because the productivity of animals and poultry decreased. Although several studies reported the effects of heat-stress in chicken, the expression profile of heat-shock proteins and heat shock factors was not investigated in the gonads and germ cells of Transylvanian Naked Neck chickens. Methods In the first experiment, 24 hours after hatching 80 chicks were heat treated on 38.5oC ambient temperature with 60% humidity for 12 hours. After maturation, their primary productivity parameters, such as egg production, abnormalities in embryo development, sperm quantity, concentration, and motility were studied following two weeks of heat-stress on 30 °C room temperature. In the second experiment, the thermal manipulation of 60 chicks was the same but 15 treated and 15 control chicks were sacrificed immediately after the treatment. The other 15–15 chickens were raised to maturity. Expression levels for two heat-shock proteins and four heat shock factors were determined by real-time PCR in the gonads of heat-treated and heat-stressed chickens. Results We found that the heat-treated layers had significantly higher egg production than the control group in heat-stressed conditions. In cockerels, the sperm quality did not differ significantly between the heat-treated and heat-stressed group and the heat-stressed but not heat-treated group. We examined the expression pattern of HSPs and HSFs in the gonads. We found that the expression of HSP90 and HSF4 increased significantly (p < 0.05) in heat-treated female chick gonads but in adult females the expression of HSF2 and HSF3 were significantly lower compared to the control. In case of adult heat-treated males, the HSP70, HSF1 and HSF3 expression levels showed a significant increase in both gonads, compared to the control expression levels (P < 0.05). Conclusion Heat shock proteins and heat-shock factors protect cells against different stressors, including heat stress. Our findings show a significant effect on egg production but not on the sperm quality after post-hatch heat treatment in heat stress condition. The presented significant differences might be related to the increased expression level of HSP90 and HSF4 in heat-treated chickens.