Bactericidal principle of the fermented aqueous extract of Stevia rebaudiana Bertoni and a possible use of the Stevia extract as a feed supplemen for prevention of the digestive tract infections.

我们以前已经证明，从菊科植物甜叶菊Bertoni的发酵提取物对广泛的食源性致病菌具有很强的杀菌活性，但它对双歧杆菌和乳酸杆菌没有显示出显著的杀灭活性。本文研究了发酵提取物的杀菌原理，并对其作为饲料添加剂预防家畜肠道感染和促进动物生长的可能性进行了试验.甜菊发酵水提物经乙酸乙酯萃取、ODS（C_）柱高效柱层析分离<18>。得到两个杀菌级分和一个增强剂级分。E.在37℃下与杀菌组分孵育1h后，大肠杆菌的活菌数从10^9cfu/ml降至&lt;10^3cfu/ml。其中一个杀菌组分在280 nm处有最大吸收，对光敏感。另一个杀菌组分被鉴定为乳酸.在实验室实验中，对沙门氏菌感染的小牛口服甜菊提取物减少了肠道中的活菌和细菌组织入侵，尽管没有阻止细菌的致死作用。3.在田间试验中，甜菊提取物口服给药对猪肠道感染有效。许多早期腹泻的动物在治疗后3天内恢复，3天后其生长速度正常。口服稀释的甜叶菊提取物促进猪的生长。在屠宰场，评价Stervia饲养猪的肝脏非常健康。猪肉的味道很好。

We have previously shown that a fermenteds extract from the Paraguayan composite plant, Stevia rebaudiana Bertoni has strong bactericidal activity towards a wide range of food-borne pathogenic bacteria, but it shows no significant killing activity to Bifidobacteria and Lactobacilli. Here we studied bactericidal principle of the fermented extract, and tested the extract for possible use as a feed supplement for prevention of the intestinal tract infections of domestic animals and for promotion of animal growth.1. Fermented aqueous extract of Stevia rebaudiana Bertoni was fractionated by the partition with ethyl acetate, followed by the high performance column chromatography using an ODS (C_<18>) column. Two bactericidal fractions and one enhancer fraction were obtained. Viability of E. coli was reduced from 10^9 cfu/ml to <10^3 cfu/ml when incubated with the bactericidal fractions at 37℃ for 1 h. One bactericidal fraction has the maximal absroption at 280 nm, and it was sensitive to light irradiation. The other bactericidal fraction was identified as lactic acid.2. In the laboratory experiments, oral administration of the Stevia extract to the Salmonella-infected calves reduced viable bacteria in the intestinal tract and bacterial tissue invasion, although not prevented the lethal effect of the bacterium.3. In the field experiments, oral administration of the Stevia extract was effective to the intestinal tract infections of piggys. Many of the animals with early-staged diarrhea were recovered within 3 days after the treatment, and their growth rate was normal threeafter. Oral adminitration of the diluted Stevia extract promoted growth of pigs. Livers of the Stervia-fed pigs were evaluated to be very healthy at the slaughter house. Taste of the pork meat was exellent.