Functional resilience of Kangayam cattle under thermal stress: Insights into cellular and immune adaptations

The study for the first time, investigates cellular and immune resilience of Kangayam cattle to heat stress in comparison with Jersey cattle. The study involves twenty-four adult cows (Kangayam cows (n = 12); Jersey cows (n = 12)) allocated randomly into four different groups of six animals each (Kangayam heat stress, Kangayam control, Jersey heat stress, Jersey control). The study period (45-days) spans over April to May months of the summer season during which the animals in control group were housed in a shed, while the other groups were expose to environmental thermal stress daily. At the end of experimental period, haematology, biochemical, cortisol, heat shock protein 70 and cytokines levels, redox status and peripheral blood mononuclear cell responses were recorded. Results revealed reduced variability in haemato-biochemical parameters, cortisol, NEFA and haptoglobin levels and significantly elevated (P < 0.001) heat shock protein 70 in heat stressed Kangayam cattle. Moreover, Kangayam cattle exhibited high stability in the expression of IL-1β, IL-6 and tumor necrosis factor and also their redox status like antioxidant enzymes activities, malondialdehyde and intracellular ROS levels, free radical scavenging activity and total thiol level were unaltered during thermal stress. In addition, Kangayam cattle PBMCs demonstrated unaltered apoptotic rate with preserved DNA integrity and increased mitochondrial membrane potential and decreased matrix metalloproteinase 2 and 9 activities. In conclusion, the current study highlights the superior cellular and immune resilience of Kangayam cattle under thermal stress conditions for the first of its kind.