Mutagenicity of carbadox and several quinoxaline 1,4-dioxide derivatives.

Carbadox (2-formylquinoxaline 1, 4-dioxide carbomethoxyhydrazone), a feed additive for swine, showed mutagenicity against Salmonella typhimurium TA 98 and TA 100 both in the absence and presence of S-9 mix. The mutagenic activity was stronger than that of quinoxaline 1, 4-dioxide and was close to that of benzo [a] pyrene.