Growth of fungi in broiler houses.

The growth of fungi in broiler houses with and without histories of problems of unknown etiology or of mycotoxicoses was studied. Fungal growth data were obtained by the strip bait method and results expressed as frequency and relative density. The frequency and relative density of fungal growth of several species were higher in problem houses than in those without problems. In problem houses many known toxic fungi and several fungi of unknown toxicity were found growing, increasing in density and frequency during the rearing period. Houses without problems (control houses) were dominated throughout the rearing period by the growth of Scopulariopsis brevicaulis. This fungus grew infrequently and in low relative density in problem houses. There was no correlation between species composition and litter removal, pH, and moisture in problem and control houses. Fungi did not grow in inside feed hoppers or in dust on rafters in the broiler houses. One thermotolerant and two thermophilic species of fungi were found growing in outside feed bins. Three generalized fungal growth patterns in litter are described and theoretical consideration of environmental factors on these patterns are discussed.