Dietary Supplementation of Vitamin C and/or Vitamin E before or after Experimental Infection withStreptococcus iniaeHas Limited Effects on Survival of Hybrid Striped Bass

Abstract

Abstract To examine the prophylactic and therapeutic value of dietary vitamins C and/or E given in megadoses against disease, juvenile reciprocal-cross hybrid striped bass (female white bass Morone chrysops × male striped bass M. saxatilis) were fed experimental diets with 2,500 mg vitamin C/kg diet (100× the established dietary requirement), 300 mg vitamin E/kg (10× the dietary requirement), or both at the requirement or megadose levels for 3 or 6 weeks before and 0, 3, or 7 d after experimental exposure to Streptococcus iniae. The first dead fish was observed 3 d following intraperitoneal injection with S. iniae, and mortality did not appear to be significantly affected by dietary vitamin level or length of feeding. Infection with S. iniae reduced tissue total ascorbate and α-tocopherol levels at 14 and 21 d postinjection relative to those in uninfected control fish. Dietary vitamin E at 300 mg/kg significantly increased mortality when fed for 3 weeks before exposure. Additionally, dietary vitamin C at ...