EVALUATION OF BACILLUS SPP. AS DIRECT FED MICROBIAL (DFM) CANDIDATES FOR AFLATOXIN Bl BIODEGRADATION IN BROILER CHICKENS

摘要

The limits of physical and chemical methods to decrease aflatoxins in feed ingredients, stimulated the search on biological approaches of degradation. Recently, we identified three Bacillus spp. candidates that showed in vitro activity to biodegradateaflatoxin Bl (AFBJ). The aim of this study was to evaluate the biodegradation potential of previously selected Bacillus spp. provided as a direct-fed microbial candidate (DFM), in broiler chickens consuming feed containing different concentrations ofAFBl. In the present study, three independent experiments were conducted. In Exp 1, broilers were allocated randomly to four groups: Control feed; feed + DFM; feed + 2ppm AFBl;feed + DFM + 2 ppm AFB1. Each group had six replicates of 20 chickens (n = 120/group). In Exp 2, broilers were allocated randomly to six groups: Control feed; feed + DFM; feed + 1 ppm AFBl;feed + DFM + / ppm AFBUfeed + 1.5ppm AFB1; feed + DFM + 1.5ppm AFB1. Each group had 5 replicates of 16 chickens (n = 801 group). In Exp 3, broilers were allocated randomly to six groups: Control feed; feed + DFM; feed + 50 ppb AFBUfeed + DFM + 50 ppb AFBUfeed + 500 ppb AFBUfeed + DFM + 500ppb AFB1, each group had 5 replicates of 10 chickens (n = 80/group). In all experiments, chickens were fed starter (dl-d7) or grower diet (d8-d21) ad libitum until the end of the experiment at day 21. All broilers were individually weighed and body weight (BW), body weight gain (BWG), feed intake (FI) and feed conversion ratio (FCR) were obtained weekly. The results of the present study show clear evidence, that not all DFM are the same, and in this case, administration of 106 spores/gram of feed showed no beneficial performance effects in two out ofthree independent experiments. In addition, even though the individual isolates incorporated in the DFM showed some in vitro activity to biodegradate AFBl, when administered in the diets at 5 different concentrations of AFBl, no significant performance differences were observed when compared with their respective control diets.