Effects of fumonisin B-1 on selected immune responses in broiler chicks

Three experiments were conducted to evaluate immune responses in chicks fed fumonisin B-1 (FB1). Day-old male chicks were randomly allotted to dietary treatments: 0, 50, 100, or 200 mg FB1/kg diet. In Experiment 1, chicks wer e fed diets for 3 wk and were injected intravenously with 4.6 x 10(6) Esche richia coli on Day 21. Blood samples were collected at 60, 120, and 180 min postinjection, and liver, spleen, and lung were collected after 180 min. C hicks fed 200 mg FB1/kg diet had significantly higher numbers of bacterial colonies in blood, spleen, and liver (P < 0.05) than control chicks. In Exp eriment 2, chicks were placed on the diets for 4 wk and were injected with 0.5 mL inactivated Newcastle Disease virus vaccine on Weeks 2 and 3 of the experiment, and primary and secondary antibody titers were measured 7 d aft er each injection. The secondary antibody response in chicks fed 200 mg FB1 /kg diet was significantly lower (P < 0.05) than that of control chicks. In Experiment 3, lymphocyte proliferation in chicks exposed to FB1 in vivo or in vitro was determined. Results of the in vivo study showed that cell pro liferation in response to mitogens was lower (P < 0.05) in chicks fed 200 m g FB1/kg diet than in control chicks. For the in vitro study, cell prolifer ation was lower (P < 0.05) when cells were exposed to 2 2.5 mu g FB1/mL. Da ta of the current study suggested that FB1 is immunosuppressive in chicks w hen present in the ration at 200 mg FB1/kg diet.