Objective   To investigate the potential effects of promoting growth additive on part of reproductive function of female rats and toxic action.

  Methods   Animal experiment was applied, and rats was treated with various doses of growthpromoting additive by oral gavage to study productive parameters and toxic index, such as age vaginal opening(VO), estrous cycle, gland/body weight coefficient.

  Results   Compared with control group(1)Rats of lower dose group had apparently higher body weight and body weight increased at the end of the experiment(P < 0.05).(2)For rats of lower dose group, age at VO was advanced significantly(P < 0.05).(3)After two-week treatment, the number of lower dose rats which entered the first estrous cycle was remarkably more than that of control group(P < 0.05), while the number of mid-dose and higher dose rats showed no obvious difference but a trend of declination.(4)Rats uterus/body weight and ovary/body weight coefficients in various groups were slightly different(P > 0.05), and also showed a trend of declination from lower to high-dose group.

  Conclusion   Growth-promoting additive showed estrogen-like effects on rats which may have certain correlation with the concentration of the former.