RESUMO
Superoxide radicals cause damage to cell by inhibiting some critical enzyme activities of the cell, lipid peroxidation in the membranes and DNA damage. Superoxide dismutases (SOD) play a critical role in regulating the oxidative stress and heat stress. As SOD regulates cell defense during heat stress, therefore the present study was designed to analyse the SOD activity in lactating animals and in growing kids of Jamunapari goats during peak heat stress period. Heat stress susceptible and tolerant phenotypes were identified based on distribution of respiration rate (RR) and heart rate (HR), the animals exhibiting RR ≥50 and HR ≥130 are recognised as heat stress susceptible (HSS) phenotype and RR ≤30 and HR ≤100 individuals are recognized as heat stress tolerant (HST) in adult goats during heat stress period. SOD activity (Inhibition percent) was 31.63% and 36.92% in lactating goats and kids at 9 months of age, respectively. Sex and birth type had significant effect (P <0.01) on SOD activity at 9 months of age of growing kids. Males had lower SOD activity than females at 9 month of age. The SOD activity of heat stress susceptible (HSS) individuals was significantly higher (P <0.01) than heat stress tolerant (HST) animals in lactating goats. There was no significant difference (P> 0.01) observed in SOD activity of kids on a within HSS and HST phenotype. Heat stress tolerant individuals had lower SOD activity than heat stress susceptible individuals during lactating stage. SOD play significant role during lactating condition as compared to growth stage in Jamunapari goats.