Research on the acute toxicity and teratogenicity of the feeding L-tryptophan

In order to evaluate the safety of the feeding L-tryptophan, we conducted acute toxicity test and teratogenicity test in rats. Rats were fed with L-tryptophan by gavage. The oral LD 50 was more than 20.0g/kg b.w. In the teratogenicity test, the doses of L-tryptophan were 5.0g/Kg b.w., 2.5g/Kg b.w. and 1.25g/Kg b.w. We set up a normal control group. The rats were fed by gavage once a day from the 7th to 17th day of pregnancy. At the 20th day of pregnancy, we counted and measured the litter size, placenta weight, live baby weight, body length, tail length, fetus malformation rate, live fetus average malformation rate, maternal fetus malformation rate, fetus death rate, absorptive fetus rate and other indicators. Then we use SPSS12.0 software to carry out data statistical analysis, and One-Way ANOVA and t-test for comparison between groups. The results showed that, when each dose group compared with the control group, there was no significant difference in average body weight, body length, tail length, placenta weight, fetus live rate, fetus death rate and absorptive fetus rate when compared to the normal control group( P >0.05), and there was no significant difference in the common deformity indexes, such as fetus malformation rate, live fetus average malformation rate and maternal fetus malformation rate between each dose group and the normal control group( P >0.05). The oral LD 50 of L-tryptophan to Wistar rats was more than 20.0g/kg b.w., and the traditional teratogenicity test was negative, indicating that the feed additive belongs to the actually non-toxic level and has no obvious teratogenicity.