Effects of dietary vitamin E on chickens infected with eimeria maxima: observations over time of primary infection.

Two trrials were conducted to define temporal changes in plasma D-alpha-tocopherol (AT) caused by infection with Eimeria maxima in chickens that consumed either low (25 ppm) or high (225 ppm) levels of dietary DL-alpha-tocopheryl acetate (VE-AC) from 1 day of age. In both trials, rates of weight gain were depressed between days 5 and 7 post-inoculation (PI) and were not influenced by the level of dietary VE-AC. Plasma AT was consistently depressed at 5 and 7 days PI in chickens consuming either level of dietary VE-AC. The pattern and degree of plasma AT depression correlated with those of plasma carotenoids. Plasma levels of NO2- + NO3- were significantly increased at 5 and 7 days PI. In trial 1, the average increase during that period was not as high in chicks consuming 225 ppm VE-AC, but in trial 2, diet had no effect on the degree of increase. Also, there were no consistent effects of dietary VE-AC on lesion scores or amount of oocysts shed. These results are in general accord with findings of earlier experiments, and we conclude that feeding high levels of VE-AC to broiler chicks from 1 day of age is not effective in mitigating the pathology, including weight gain depression and development of mucosal lesions, during E. maxima infections or in modifying immune response events associated with phagocytosis as indexed by plasma NO2- + NO3-. The likely basis for the ineffectiveness of feeding this fat-soluble form of vitamin E is that it is malabsorbed during E. maxima infection in the same manner as carotenoids and becomes less biologically available to infected tissues during the acute phase of infection.