Biodetoxification of aflatoxin-contaminated chick feed.

Two studies were done to study detoxification of aflatoxin (AF)-contaminated chick feed with Nocardia corynebacteroides (NC). In the first study, pathogenicity of the bacteria was studied; in the second, the nutritional value of detoxified feed was evaluated. Commercial corn was divided into 2 sublots, one of which was contaminated with AF. Both lots were divided into 2 parts; the first was inoculated with NC. Four corn-soybean diets were prepared from the 4 corn lots. A completely randomized design was used with 2 x 2 factorial arrangement in which the factors were AF contaminated or not and NC inoculated or not. One hundred Ross 308 chicks (1-d-old, male) were used in 4 treatments with 5 repetitions and 5 chickens per cage. Bird weight and feed consumption were recorded weekly. Each week, 1 chick per treatment repetition was killed for histopathologic analysis of liver, kidney, bursa of Fabricius, pancreas, and small intestine (duodenum, jejunum, and ileum) and for analysis by scanning electron microscopy of the 3 sections of the intestine. At 21 d (the end of both experiments), 1 chick per treatment repetition was killed, and moisture, lipid content, and residual AF in liver were detected. Results at 3 wk did not show differences between treatments (P > 0.05) in any of the variables. In the second study, the same methodology was used except that greater levels of AF were used (800 and 1,200 mug of AFB1/kg of feed). Results showed differences (P < 0.05) in body weight, lipid content, and residual AF in liver. Histopathologic studies showed statistical differences in lesion severity in liver, duodenum, and kidney. Scanning electron microscopy analysis showed severe lesions of intestinal mucosa that mainly affected tight junctions in AF treatments. It can be concluded that NC is safe for chicks and may be used to partly detoxify chicken feed contaminated with AF.