Aflatoxin B1, Selenium and Saccharomyces cerevisiae in the immune response of broiler chickens in Zulia state, Venezuela

This research aimed at evaluating a 42 day long exposure to Aflatoxin B-1 70 mu/kg (AFB(1)) on poultry immune responses and an application of 2.5 mg/kg of selenium (SEL) and 0.1% Saccharomyces cerevisiae (SC) as a dietary supplement to prevent aflatoxicosis. In a factorial experiment design with eight treatments of 15 chickens each and four repetitions (480 male Hubbard x Hubbard) was used. The treatments were: T-1= control (basal diet common for all the groups); T-2= AFB(1); T-3= SC; T-4 = AFB(1)+ SC; T-5= SEL; T-6= AFB(1)+ SEL; T-7= SC + SEL; T-8= AFB(1)+ SC+ SEL. The parameters evaluated were: number of leucocytes (WC); percentage distribution of leucocytes (LEU); antibody title for Gumboro and Newcastle (AT); Serum proteins (SP), Gamma-globulins (Gamma) Albumin/globulin index (alb/glo); Bursa/body Weight (B/BW); viable lymphocyte percentage in Fabricius Bursa (VLP); Bursal degree of Histopathological lesion (LD). Data were analyzed using Variance analysis using the SAS GLM procedure. Treatment means were analyzed by Dunnet's test, while the Kruskal Wallis test was used to analyze LID variable. Results indicated that AFB(1) decreased GB, induced an arise in lymphocytes and a hetherophylic depletion, decreased PS and B/BW, and increased the degree of lesion in Bursa. Thus, the immune response was impaired. Selenium in the presence of AFB(1) increased PS, improved cellular response and showed an important preventive effect in relation to Bursal damage. The yeast culture did not prevent alterations in any immunological variable affected by AFB(1). This data suggest that long time-low level exposure to AFB(1) affects immune response in broilers and that supplementation with 2.5 mg/kg of Selenium is a useful tool in preventing the problem. The Saccharomyces cerevisiae level used in this assay showed no profitable results.