饲用五环三萜提取物的致突变试验

Mutagenicity test of feed pentacyclic triterpenoid extract

试验旨在通过鼠伤寒沙门氏菌回复突变试验(Ames试验)、小鼠骨髓细胞微核和精子畸变试验,评价五环三萜提取物作为饲料添加剂是否具有潜在的致突变性。Ames试验中受试物剂量组为0.008、0.040、0.200、1.000、5.000 mg/皿,另设阴性对照(灭菌水、DMSO)及阳性对照组,每个处理分别设有代谢活化系统(+S9)和无代谢活化系统(-S9)两个系列,测定试验菌的回变菌落数。小鼠骨髓细胞微核试验中受试物剂量组采用1.25、2.50、5.00 g/kg灌胃给药,并设阳性对照(环磷酰胺)及阴性对照(1%羧甲基纤维素液),共给药2次,每次间隔24 h,测定小鼠骨髓细胞微核率。精子畸变试验中受试物剂量组采用1.25、2.50、5.00 g/kg灌胃给药,设阳性对照(环磷酰胺)及阴性对照(1%羧甲基纤维素液),共给药5次每次间隔24 h,于第1次给药5周后处死小鼠,统计精子畸形率和畸形种类。结果显示:不同剂量组与对照组相比,Ame试验中平均回变菌落数均在溶剂组2倍以内,无剂量-反应关系;骨髓细胞微核率和精子畸变率均无显著影响(P>0.05);致突变试验结果均为阴性。研究表明,受试物五环三萜提取物不具有致突变作用。

The purpose of the experiment is to evaluate whether pentacyclic triterpeneds extracts as a feed additive has potential mutagenicity through Ames test,micronucleus test and sperm deformity test.In Ames test,substance dose groups were set as 0.008,0.040,0.200,1.000 and 5.000 mg/dish.Negative control(steriled water,DMSO)and positive control groups were set.Each treatment was set with two series of metabolic activation system(+S9)and non metabolic activation system(-S9),determining the number of returning mutant colonies of test bacteria.In the micronucleus test,the dose groups of test substance were set as 1.25,2.50 and 5.00 g/kg by gavage,and the positive control(cyclophosphamide)and negative control(1%carboxymethyl cellulose solution)were set up.The micronucleus rate of mouse bone marrow cells was measured at an interval of 24 h after twice administration.In the sperm deformity test,the dose groups of test substance were set as 1.25,2.50 and 5.00 g/kg by gavage,and the positive control(cyclophosphamide)and negative control(1%carboxymethyl cellulose solution)were set up.The interval was 24 h for each of the five times of administration.The mice were killed 35 d after the first administration,and the sperm abnormality rate and types were counted.Compared with the control group,the average number of retrogressive colonies in Ame experiment was less than twice that in solvent group,and there was no dose-response relationship.The micronucleus rate of bone marrow and sperm aberration rate had no significant effect(P>0.05).Mutagenic test results were all negative.The results shows that pentacyclic triterpenoids exhibits no mutagenic effect.