生防细菌枯草芽孢杆菌A97对小鼠的急性毒理作用研究

枯草芽孢杆菌(Bacillus subtilis)A97是一株具有广谱抗真菌活性的生防细菌,对常见果蔬采后病害有显著防治效果。通过小鼠急性经口毒性和细菌移位试验,评价B.subtilis A97及其代谢产物对哺乳动物的生物安全性,为该菌株在果蔬采后病害防治中的安全应用提供依据。采用最大剂量耐受法连续14 d每天对小鼠灌喂菌体浓度为1.0×109 CFU/m L的B.subtilis A97发酵液0.4 m L(对照组灌喂无菌生理盐水),观察和测定小鼠的一般体征、脏器指数、血相和肝脏生化等指标,并检测小鼠血液和组织中是否发生细菌移位。结果表明,B.subtilis A97发酵液对小鼠的半数致死剂量大于20 000 mg/kg BW,各处理组小鼠未出现明显中毒症状及死亡现象。处理组小鼠一般体征、脏器指数、血清和肝脏生化指标与对照组相比差异不显著,且小鼠血液和其他组织样本中均未检测到由B.subtilis A97引起的细菌移位。由此推断B.subtilis A97及其代谢产物对哺乳动物安全无毒副作用,可在农业生产中使用。

Acute Toxic Effect of Antagonistic Bacteria Bacillus subtilis A97 on Mice

Bacillus subtilis A97 had broad-spectrum antifungal activity and significant control effects on postharvest diseases of fruits and vegetables. The mouse acute oral toxicity and bacterial translocation test were made to evaluate the safety of B. subtilis A97 and its metabolite for mammal and provides basis for safety application of this antagonist bacteria in the horticultures postharvest protection. The acute oral toxicity test was using maximum tolerated dose intragastric administration fermentation broth of B.subtilis A97 (1.0×109 CFU/mL) with mice for consecutive 14 days (the control mice were fed with sterilized saline water), then the physical signs, visceral index, hemogram and liver biochemical indicators were observed and recorded. And check the bacterial translocation in blood and tissues specimens. The results showed that, the median lethal dose(LD50) of B.subtilis A97 fermentation broth was more than 20 000 mg/kg BW. There was no evident poisoning symptom and death in treated groups, and all indicators had no significant differences with the control group. Also there was no detectable bacterial translocation which caused by B.subtilis A97 in blood and tissues specimens in mice. It followed that B.subtilis A97 and its metabolite had no significant toxic and side effects for mammal, and it could be applied in agricultural production.