It suggested that the nitrites reaching 900 mg/kg in feeds caused poor performance and had ill-effect on health of ducks. The NOEL of nitrite in formula feed for ducks may be 600 mg/kg.

• 因此 ,日粮中亚硝酸盐含量达到 90 0mg kg时 ,肉鸭健康状况明显受到不良影响 ,建议饲料中亚硝酸盐的无明显作用水平 (NOEL)定为 6 0 0mg kg。