title: Carcinogenesis Bioassay of Gum Arabic (CAS No. 9000-01-5) in F344 Rats and B6C3F1 Mice (Feed Study).
abstract: A carcinogenesis bioassay of gum arabic (81-86% pure), a widely used food stabilizer, was conducted by feeding diets containing 25,000 or 50,000 ppm of the test substance to 50 F344 rats and 50 B6C3F1 mice of each sex for 103 weeks. Groups of untreated rats and mice of each sex served as controls. Throughout most of the study, mean body weights of dosed male and female mice and of dosed male rats were comparable with those of the controls; mean body weights of the dosed female rats were slightly lower than those of the controls. No other compound-related clinical signs or effects on survival were observed. Mean daily feed consumption by high-dose rats and mice of either sex was 85% to 94% that of the controls. The high dose (50,000 ppm) used in this bioassay is the maximum concentration (5%) currently used in feed studies. Statistically significant (P<0.05) increasing trends were observed for the number of female mice with hepatocellular carcinomas (1/49, 2/50, 6/50), and with total liver tumors (4/49, 2/50, 10/50). No statistically significant differences were obtained when comparing the control rates with those observed in the treated groups. These observations were not considered to be clearly associated with the dietary administration of gum arabic. Thus, no compound-related neoplastic or nonneoplastic lesions were found in rats or mice of either sex. Under the conditions of this bioassay, gum arabic was not carcinogenic for F344 rats or B6C3F1 mice of either sex. Levels of Evidence of Carcinogenicity: Male Rats: Negative Female Rats: Negative Male Mice: Negative Female Mice: Negative Synonym: gum acacia