HSP70 as a marker of heat and humidity stress in Tarai buffalo

Heat and humidity stress is a constant challenge to buffalo rearing under tropical climatic conditions. Heat shock proteins (HSPs) constitute a ubiquitous class of highly conserved proteins that contribute to cell survival during different conditions of stress. The present study was carried out in Tarai buffaloes to study the expression of HSP70 in their peripheral blood mononuclear cells during different seasons and establish it as a marker of heat and humidity stress in buffaloes. Blood samples were collected from each healthy, non-lactating and non-pregnant buffalo above 2 years of age, once in the month of January (temperature-humidity index (THI) < 72) and in the month of May (THI > 72). Blood samples were also collected during October (THI = 72) to be used as calibrator/control. Real-time PCR was used to profile the HSP70 gene expression in the peripheral blood mononuclear cells (PBMCs). The relative expression values of HSP70 in Tarai buffalo was found to be significantly higher (P < 0.05) during summer season (2.37 +/- 0.12) as compared to winter season (0.29 +/- 0.04). The expression positively correlated with changes in physiological parameters like respiration rate (RR), pulse rate (PR) and rectal temperature (RT). In conclusion, it can be said that RR and HSP70 may act as characteristic physiological and cellular markers of heat and humidity stress in buffaloes.