Neutrophil function in experimentally induced mastitis in goats, inoculated with Staphylococcus aureus supplemented and not supplemented with vitamin E (acetate DL-a-tocopherol) was evaluated. Fourteen pregnant Saanen goats, between 8 and 12 months of age all negative in bacteriological milk cultures, were used. Seven goats were treated with 2,000 IU of vitamin E, by intramuscular injection, on the day of the parturition and seven days later, and seven goats were not tested. On the 10th day the two groups were inoculated with 300 colony forming units of Staphylococcus aureus (ATCC 25923), diluted in 10ml of physiologic saline, by injection in the left mammary gland through ductus papillari. Blood samples were evaluated for neutrophil function by the nitroblue tetrazoliun test (NBT), before infection and at zero, 12, 24, 48 and 72 hours post-infection. At this moment, intra-mammary antimicrobial treatment was instituted, and a final assessment of neutrophil function was made 48 hours after the last treatment. Blood samples for vitamin E concentration were collected on the day of the parturition, at the day of infection, 48 hours post-infection and 48 hours post-treatment. The vitamin E concentration was determined by high performance liquid chromatography. The results of NBT-NE (not stimulated) did not detect chronological or group differences. However, by the test of NBT-E (stimulated) a significant difference between treatments on 12 and 72 hours post-infection, with higher values in the animals without supplementation of vitamin E was detected. It is concluded that the supplementation with vitamin E reduced the percentage of positive NBT-E neutrophils.
vitamin E; neutrophil function; NBT; goats
