Five-Month Oral (Diet) Toxicity/lnfectivity Study of Bacillus thuringiensis Insecticides in Sheep

Five-Month Oral (Diet) Toxicity/Infectivity Study of Bacillusthuringiensis Insecticides in Sheep. HADLEY, W. M., BURCHIEL,S. W., MCDOWELL, T. D., THILSTED, J. P., HIBBS, C. M., WHORTON,J. A., DAY, P. W., FRIEDMAN, M. B., and STOLL, R. E. (1987).Fundam. Appl. Toxicol. 8, 236–242. Bacillus thuringiensisinsecticides (Bt) [Dipel (test substance D or Thuri-cide-HP(test substance T)] were administered in the diet for 5 monthsto castrated mixed ram-bouillet/merino sheep (24–34 kgat the beginning of the study) at a dose of 500 mg/kg/day (approximately10¹² spores per day). No treatment-related effect was seen onweight gain or clinical chemistry parameters nor were significantgross clinical changes observed. Several blood and tissue samplestaken just prior to the time the animals were killed or at necropsywere found to be positive for Bt when cultured. Detailed grossand microscopic pathologic examination of the sheep revealedseveral incidental lesions. However, the only lesion that mayhave been associated with the treatment was lymphocytic hyperplasiain Peyer's patches seen in the cecum of three sheep and it wasnot considered to be clinically significant.