This study was designed to evaluate and characterize any adverse effect of
nisin A, when administered to both sexes of F344/DuCrlCrlj rats (10 males and 10 females in each group) at dietary levels of 0%, 0.2%, 1.0% and 5.0% for 90 days. Animals given NaCl at a dietary level of 3.712% (equivalent to the NaCl content in 5.0%
nisin A diet) served as a reference material treated group. There were no deaths, and the treatment had no toxicologically significant effects on clinical signs,
body weights, food consumption, ophthalmology, hematology, or gross pathology. Statistically significant increases of water consumption, urine volume, and urinary
sodium and
chlorine, and decreases of urinary
potassium and serum
sodium, along with increases of absolute and relative kidney weight, and incidences of minimal squamous cell
hyperplasia of limiting ridge in the forestomach, were found in
nisin A-treated groups. It was considered that these changes were related to NaCl, since they were also noted in rats given diet containing the reference substance. Thus, no toxicologically significant changes were apparent in both sexes of F344/DuCrlCrlj rats fed diet containing 0%, 0.2%, 1.0% and 5.0%
nisin A for 90 days. Therefore, the no-observed-adverse-effect level (NOAEL) for
nisin A was concluded to be a dietary level of 5.0% (2996 mg/kg/day for males and 3187 mg/kg/day for females).