Individual and Combined Effects of Aflatoxin and Ochratoxin A on Bruising in Broiler Chickens

A 2 × 2 factorial design with treatments of 0 and 2.5 μg/g aflatoxin and 0 and 2.0 μg/g ochratoxin A was used to evaluate the individual and combined effects of these mycotoxins on bruising and bloody thigh syndrome in broiler chickens. Trial 1 consisted of four replicate pens of 10 broilers per replicate, which were maintained on these dietary treatments from 0 to 3 weeks of age. At 3 weeks of age two replicate pens per treatment were randomly selected and placed on toxin-free feed with two replicate pens remaining on toxin feed until they were 6 weeks of age when the trial was concluded. In Trial 2 three replicate pens of 38 broilers per treatment were maintained on toxin feed from 0 to 3 weeks of age. At 3 weeks of age 13 broilers per replicate were placed on toxin-free feed with 25 broilers per replicate remaining on toxin until they reached 7 weeks of age when Trial 2 was concluded. These data indicate that a synergistic toxicity exists between aflatoxin and ochratoxin A to significantly (P<.05) decrease body weight. Body weights of broilers on aflatoxin or ochratoxin A diets for only 3 weeks partially recovered by 6 or 7 weeks of age; however, the body weights of broilers on the interaction treatments for only 3 weeks remained significantly (P<.05) depressed at 6 and 7 weeks of age. Although frank hemorrhaging was. not associated with this mycotoxin interaction, elevated prothrombin times and increased incidence and severity of thigh and breast bruises implicate these mycotoxins individually and in combination with increased susceptibility to bruising during live-haul and processing. Prothrombin times fully recovered in broilers receiving these treatments for only 3 weeks; however, susceptibility to bruising did not recover. These data also suggest that the effects of ochratoxin A are longer lasting than the effects of aflatoxin.