EVALUATION OF PHYSIOLOGICAL INDEXES IN MICE VACCINATED WITH PROTEIN-ERGOTAMINE CONJUGATES AND FED AN ENDOPHYTE-INFECTED FESCUE DIET

Objectives-To assess effects of vaccination against fescue toxicosis o n weight gain, serum prolactin and cholesterol concentrations, and alk aline phosphatase (ALP) activity in mice fed an endophyte-infected (EI ) or endophyte-free (EF) fescue diet. Animals-50 six-week-old male BAL B/c mice. Procedure-Mice were randomly allocated to the following 5 gr oups: 1, vaccinated intraperitoneally with a bovine serum albumin-ergo tamine (EG) conjugate and fed an EI fescue diet; 2, orally vaccinated with cholera toxin (CT) subunit B-EG conjugate mixed with free CT and fed an EI fescue diet; 3, not vaccinated and fed an EI fescue diet; 4, passively vaccinated with monoclonal antibodies specific for ergovali ne (EV) and fed an EI fescue diet; and 5, not vaccinated and fed an EF fescue diet. Results-Antibodies against EG and EV were in serum of mi ce of groups 1 and 4, respectively. Secretory IgA and IgG coproantibod ies against EG were induced in mice of group 2. Weight increased in gr oups 1 and 2 and tended to be increased in group 4 versus group 3. Pro lactin concentration was similar in all groups; cholesterol concentrat ion was decreased in groups 1, 3, and 4, compared with group 5. Compar ed with that in group 5, serum ALP activity decreased in groups 1 and 4 and was further decreased in group 1, compared with that in groups 2 and 3; it was negatively correlated with anti-EG titer. Conclusions a nd Clinical Relevance-Induction of anti-EG antibodies and administrati on of EV monoclonal antibodies tended to increase short-term weight ga in in this murine model of fescue toxicosis. However, systemic IgG ant ibodies against EG or EV antibodies were not protective against decrea ses in serum ALP activity and cholesterol concentrations. Clinical sig nificance of decreased ALP activity associated with vaccination is unk nown, but represents a worsening of a response often associated with f escue toxicosis in cattle.