Effects of probiotic (Saccharomyces cerevisiae) and ascorbic acid on oxidative gene damage biomarker, heat shock protein 70 and interleukin 10 in broiler chickens exposed to heat stress

Heat stress is a prominent factor responsible for losses economically in poultry meat industry due to adverse effects on the general performance of broiler chickens. In this study, we evaluated the effects of probiotic (Saccharomyces cerevisiae) and ascorbic acid on oxidative gene damage biomarker, heat shock protein 70 (HSP70) and interleukin 10 (IL-10) in broiler chickens exposed to heat stress under natural conditions. Fifty-six broiler chickens served as the subjects, they were divided into 4 groups of 14 as follows: group I (control), group II (probiotic S. cerevisiae at 1 g/kg of feed), group III (ascorbic acid at 200 mg/kg of feed) and group IV (probiotic + ascorbic acid at 1 g/kg and 200 mg/kg of feed, respectively). The treatments were administered via feed for 35 days (D1 to D35). Enzyme-linked immunosorbent assay (ELISA) and one step real time reverse transcription polymerase chain reaction (RT-PCR) was utilised to study the effects of heat stress on the expression levels of 8-hydroxy-2′-deoxyguanosine (8-OHdG), HSP70 and IL-10 respectively, in broiler chickens raised during the hot summer season. The level of 8-OHdG gene was significantly lower in the probiotic administered group. The expression level of HSP70 was lowest in the ascorbic acid group while, IL-10 level of expression was highest in the probiotic + ascorbic acid group. The administered antioxidants were efficient in exhibiting anti-stress effects at the level of gene expression. We conclude that probiotic, ascorbic acid and probiotic + ascorbic acid reduced oxidative gene damage, affected the expression of HSP70 and increased the level of IL-10 gene respectively, in broiler chickens exposed to heat stress.