Toxicogenicity of Moldy Feed for Young Chicks

Abstract

Feeds suspected of causing a hemorrhagic syndrome in young pigs were found to prolong the prothrombin time of chicks. To study the role of specific mold species present in these feeds, mold cultures isolated from the source feeds were grown on moistened corn and soybean meal substrates. The moldy substrate made up 45% of the total weight of the test diet subsequently fed to small groups of day-old White Plymouth Rock chicks. Most of the molds were innocuous, and permitted normal growth and feed conversion. Species that had no serious adverse effects included A spergillus candidus, A. niger, A. repens, A. ruber, Penicillium cyclopium, Trichoderma viride, and some isolates of Fusarium moniliforme. In a few cases some growth stimulation was observed. However, in most cases growth was slightly depressed.None of the molds tested had any significant effect on the chicks’ prothrombin times. One isolate of F. moniliforme produced a thiaminase. The thiamine deficiency caused by this isolate could be prevented by adding more thiamine to the diet, by autoclaving the moldy substrate, or by injecting the chicks with thiamine hydrochloride. Aspergillus ochraceus was toxic, although the toxicity was not due to ochratoxin. This culture depressed chick growth and caused mortality; on gross examination of the chicks, the only abnormality was enlarged gall bladders. Molds are highly individualistic in their effects upon young chicks. Most are harmless, but a few produce vitamin antagonists or potent toxins.