Abstract for TR-221

A carcinogenesis bioassay of locust bean gum, a widely used food stabilizer,was conducted by feeding diets containing 25,000 or 50,000 ppm of the testsubstance to 50 F344 rats and 50 B6C3F1 mice of either sex for 103 weeks.Groups of 50 untreated rats and mice of either sex served as controls.

Mean body weights of high-and low-doserats of either sex, of low-dosemale mice, and of high-and low-dosefemale mice were comparable with those of the controls; mean body weightsofhigh-dosemale mice were slightly lower than those of controls. No othercompound-relatedclinical signs or effects on survival were observed. Although the rats andmice might have been able to tolerate higher doses, 50,000 ppm (5%) is therecommended maximum concentration of a test chemical mixed in feedaccording tothe guidelines of the Bioassay Program.

Although alveolar/bronchiolar adenomas occurred in low-dose male mice at asignificantly (P=0.017) higher incidence than that in the controls (7/50,17/50, 11/50), no significant statistical results were obtained when thecombined incidence of animals with either alveolar/bronchiolar adenomas orcarcinomas was analyzed (14/50, 21/50, 14/50). Cortical adenomas in theadrenalgland of female rats occurred with a statistically significant (P=0.042)positive trend (1/50, 4/50, 6/50), but comparisons between test groups andthecontrol group were not statistically different.

Under the conditions of this bioassay, locust bean gum was not carcinogenicformale or female F344 rats or B6C3F1 mice.