author(s)
A Sihag, SS Singhal, Sunita and N Kataria

abstract
A study was carried out in male and female buffalo calves of Murrah breed belonging to arid tracts from India to find out status of antioxidants and free radical scavenging enzymes during hot ambience. Blood sample were collected during moderate and hot ambiences. Maximum ambient temperature ranged from 44.5-46.5 degree centigrade. All calves were managed in similar condition and were apparently healthy. The antioxidants selected were Vitamin C and Glutathione and free radical scavenging enzymes was Glutathione reductase. The moderate (control) mean values of vitamin C and Glutathione in erythrocytes were 2.50±0.02 µmol gHb-1 and 1.51±0.03µmol gHb-1, respectively. The mean values of vitamin C and Glutathione in erythrocytes were 1.54 and 1.23 times lower, respectively during extreme hot ambience than respective moderate ambience mean values. The moderate (control) mean values of Glutathione reductase in erythrocytes were 0.82±0.01kU gHb-1. The erythrocytes mean values was 1.97 times higher during extreme hot ambience than respective moderate ambience mean values. The sex and age effects were significant (p≤0.05) in moderate and hot ambiences for all parameter studied. The mean values were significantly (p≤0.05) higher in male buffalo calves than female buffalo calves. In each ambience the age effect showed a significant (p≤0.05) increase in the mean values being highest in the buffalo calves of 6 months- one year of age. Results clearly indicated that status of antioxidants and free radical scavenging enzymes changed in heat stressed calves probably to scavenge higher number of free radicals formed during hot ambience. All above three parameter used as important biomarker of oxidative stress. Present study provided data which can be used as reference values to for future studies and for diagnostic purposes.