Six-month toxicity study of butylated hydroxyanisole in beagle dogs

Abstract

Groups of three or four male and female beagle dogs were maintained for 6 months on diets containing BHA at concentrations of 0 (control group), 0.25, 0.5 and 1.0% (w/w). The average daily intake of BHA was about 60 mg/kg body weight in the 0.25% group, 110 mg/kg in the 0.5% group and 220 mg/kg in the 1.0% group. All animals survived the entire experimental period without showing signs of toxicity other than a dose-related retardation of growth. Serum biochemical examinations conducted at 1, 3 and 6 months revealed a slight decrease in albumin concentration and an elevation of alkaline phosphatase and leucine aminopeptidase activity in the higher dose groups. Histopathological and histometrical examination showed no evidence of mucosal alteration in the stomach, oesophagus or duodenum attributable to the administration of BHA. The mitotic index in the squamous epithelium of the distal oesophagus was comparable in the control and BHA-treated groups. Liver weights were increased in BHA-treated groups, but there were no related histopathological changes. From these data it is concluded that feeding of BHA-supplemented diets at palatable concentrations for 6 months has no pathological effects on the stomach, oesophagus, duodenum or liver of beagle dogs.