Effects of moniliformin on performance and immune function of broiler chicks

Three trials were conducted to evaluate the effect of moniliformin (M) on p erformance and immune function in chicks. Day-old chicks were randomly assi gned to four dietary treatments (0, 50, 75, or 100 mg M/kg diet). In Trial 1, chicks were placed on treatments for 3 wk and were injected intravenousl y with 4.6 x 10(6) Escherichia coli on Day 21. Blood samples were collected at 60, 120, and 180 min after inoculation, and liver, spleen, and lung wer e collected at 180 min postinjection. Compared with control chicks, chicks fed 75 and 100 mg MI kg diet had higher (P < 0.05) numbers of E. coli colon ies in the circulation, liver, and spleen. In Trial 2, chicks were placed o n diets for 4 wk and were injected with 0.5 mt Newcastle disease virus (NDV ) vaccine intramuscularly on Weeks 2 and 3 of the experiment. The primary a nd secondary anti-NDV antibody titers were measured 7 d after each injectio n. Chicks fed 100 mg M/kg diet had lower (P < 0.05) secondary antibody tite rs than did control chicks. In Trial 3, lymphocyte proliferation in chicks exposed to M in vivo and in vitro was determined. Results of the in vivo st udy showed that cell proliferation in response to mitogens from control- an d M-fed chicks did not differ (P > 0.05). For the in vitro study, lymphocyt e proliferation decreased linearly (P < 0.01) with increased concentrations of M. In all three trials, chicks fed 100 mg M/kg diet had lower (P < 0.05 ) feed intake and weight gain than did control chicks. Data from the curren t study suggested that M decreased performance and immune response in chick s at the level of 75 mg/kg diet.