Nitroblue tetrazolium reduction of neutrophils in heat stressed goats is not influenced by selenium and vitamin E injection

Experiment was designed to determine whether heat stress suppresses neutrop hil function and injections of selenium and vitamin E prior to heat stress prevent suppression of neutrophil function in goats. Twelve female goats we re divided into 2 groups of 6 each and were kept at 25 degrees C. Goats in the treatment group were injected intramuscularly with 0.1 mg/kg of seleniu m and 2.72 IU/kg of vitamin E at 8 and 1 day prior to the initiation of hea t stress. The other group was kept as control. All goats were exposed to ho t environment at 38 degrees C from day 0 through 8. Decreased tendency in p lasma cortisol concentrations and temporary increase in plasma glucose conc entrations were shown in both groups. In the control group, plasma selenium concentration gradually increased and alpha-tocopherol concentration decre ased during the first 2 days. After the second injection with selenium and vitamin E, plasma selenium and alpha-tocopherol concentrations significantl y increased and remained higher than those in the control group. Whole bloo d glutathione peroxidase (GSH-Px) activity in the treatment group tended to be greater than that in the control group, but no significant difference w as observed between 2 groups. The nitroblue tetrazolium (NBT) reduction by activated neutrophils significantly decreased on day 6 in the control group but not in the treatment group. The NBT reduction by resting neutrophils s ignificantly decreased in both groups. These data suggest that heat stress depresses neutrophil function, and selenium and vitamin E injection prior t o heat stress has no apparent effect on neutrophil function during the stre ss.