Toxic secondary metabolite production by thermophilic fungi of feedlot compost and silage

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Rogers, Laurence C., 1947-
Hendrickson, Donald E.
Issue Date
Thesis (M.S.)--Ball State University, 1975.
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Extensive research has been compiled on mycotoxin production by mesophilic fungi. However, toxin production by the thermophilic fungi has only slightly been explored. In 1970 Sister Donovan of this laboratory hinted at the possibility of mycotoxin production in thermophiles when she demonstrated that extracts of Fenicillium duponti were toxic towards brine shrimp (Artemia,salina).Thermophilic fungi from natural composting substrates and from existing laboratory stock cultures were investigated to determine the possibility of mycotoxin production by thermophilic fungi. Three bioassay organisms were used to test the toxicity of the thermophilic fungi extracts.Sixteen of the 16 thermophiles reduced brine shrimp viability by more than 25% over controls. Ten of the 16 thermophiles produced toxic substances at each of three fungal incubation temperatures.Germinating Bacillus megatherium spores were found sensitive to extracts of 9 of the 16 thermophiles. Five of the nine thermophiles produced bacterial toxic substances at each of three fungal incubation temperatures.All embryos exposed to the thermophilic extracts lived and developed normally showing no sign of somatic deformities upon opening the eggs. One-day-old hatched chicks were then investigated. Sixteen of the 48 chicks injected with thermophilic extracts manifested viscerallesions of the heart, liver and stomach on autopsy seven days after injection.Results of three bioassays indicate that the toxic secondary metabolites were found to be present in crude extracts of 16 thermophilic fungi. Data indicated that many of the thermophiles produced toxic substances at each of three incubation temperatures.Ball State UniversityMuncie, IN 47306