Toxicity of Diplodia maydis to broilers, ducklings, and laying chicken hens.

The toxicity of corn culture material of Diplodia maydis to ducklings, chicken broilers, and laying hens was investigated. Screening trials in ducklings using a 50% dietary concentration of D. maydis culture material showed that thirteen out of sixteen isolates obtained from different corn samples from South Africa as well as ones from the US and Argentina were highly toxigenic. Culture material of two isolates added as 20, 10, and 5% of the diet also proved to be toxic in ducklings. Incorporation of D. maydis culture material of two different South African isolates at 5%, 2% and 1% dietary concentrations in broilers resulted in significantly poorer weight gains. These isolates, both capable of inducing diplodiosis in ruminants and both acutely toxic in ducklings, nevertheless differed significantly in their toxigenic effect in broilers. Feeding of 5% culture material to laying hens for 7 days resulted in a drastic (43%) drop in egg production. Even at a .5% dietary level, egg production as well as egg weights of laying hens were significantly reduced. These results show that the regular and widespread occurrence of D. maydis in South African corn may be of economic importance in the poultry industry.