Gavage administration of the fungal toxin fumonisin B1 to female Sprague-Dawley rats

The fungal toxin fumonisin B(1) (FB(1)) is a contaminant of corn-based foods and feeds produced by members of the genus Fusarium. Fumonisin B(1) toxicity was examined using gavage administration of purified toxin to female Sprague-Dawley rats. For 11 consecutive days each rat received a single dose of FB, at the following concentrations: control (saline), 1, 5, 15, 35, or 75 mg FB(1)/kg body weight/d. Significantly depressed body weight and food consumption occurred at 35 and 75 mg FB(1)/kg/d. By the end of the dosing period there were no significant changes in food consumption. Kidneys and bone marrow were most sensitive to FB(1) exposure. Changes in renal morphology were observed from 5 to 75 mg FB(1)/kg/d, accompanied by transient changes in urine osmolality and urine enzyme levels. increased cellular vacuolation was the primary change associated with bone-marrow toxicity, starting at doses of 5 mg FB(1)/kg/d. Hepatotoxicity was indicated by reduced liver weight, elevated serum alanine amonitransferase (ALT), and mild histopathological changes occurring at doses of 15 mg FB(1)/kg/d and higher. Increased cytoplasmic vacuolation of adrenal cortex cells occurred in rats treated with 15 mg FB(1)/kg/d and higher, indicating that the adrenals are also potential targets of FB(1). Elevated serum cholesterol, which is a consistent response to FB(1), was observed at 5 mg FB(1)/kg/d and higher. Based on responses in this study, gavage is an appropriate substitute for longer feeding studies. Compared to previous work with male rats, gender-related differences in FB(1) responses lacked consistency but indicated that males may be marginally more sensitive than female Sprague-Dawley rats.