玉米、豆粕和麦麸提取物对4株乳酸杆菌胆盐耐受力的影响

Influence of corn,soybean meal,wheat bran extracts on the bile tolerance of four strains of Lactobacilli

模拟猪十二指肠高胆盐环境,研究玉米、豆粕和麦麸提取物对乳酸杆菌胆盐耐受力的影响.将约氏乳酸杆菌JJB3、SNZ10,罗伊氏乳酸杆菌MNZ8、KNZ4等4株菌在分别含有玉米、豆粕和麦麸提取物的1.0%胆盐、pH7.0的磷酸盐缓冲液中作用4h,检测活菌数;另以不同浓度葡萄糖和酵母提取物替代3种提取物,探讨饲料原料提取物对乳酸杆菌胆盐耐受力的作用机制.结果表明:在未添加提取物的对照组,4株乳酸杆菌活菌数极显著下降(P<0.01),其中MNZ8对胆盐最敏感,活菌数下降1.74个对数值,而KNZ4的耐受力最强,仅下降1.16个对数值.分别添加3种提取物后,4株乳酸杆菌的胆盐耐受力均显著提高(P<0.05),其中,玉米、豆粕和麦麸提取物对JJB3的胆盐保护作用最强,菌株存活率从对照组的78.12%分别提高到99.35%、99.48%、99.74%,对MNZ8的胆盐保护作用最弱.葡萄糖能显著提高乳酸杆菌耐胆盐能力,而酵母提取物作用较弱.说明在胆盐环境中,3种提取物均能显著提高4株乳酸杆菌的耐受力,对乳酸杆菌的保护作用是:麦麸提取物>豆粕提取物>玉米提取物.

The effects of corn, soybean meal and wheat bran extracts on the viability of Lactobacilli were evaluated under simulated high bile level in the pig intestine. The viable counts of the tested strains JJB3, SNZ10, MNZ8 and KNZ4 were detected at the presence of the feed extracts added with l. 0% bile salt dissolved in pH 7.0 phosphate-saline buffer for 4 h. In order to evaluate the effect of the feed constituents on the cell survival, the individual effect of glucose and free amino nitrogen （FAN） was examined. The results indicate that the viable numbers showed a significant decrease （P〈0. 01） in the absence of feed extracts. L. reuteri MNZ8 decreased by 1.74 logarithm value, while L. reuteri KNZ4 dropped by 1.16 logarithm value. However, the viability of the four strains tested was improved significantly in the presence of feed extracts （P〈0.05）. The bile tolerance of the strain JJB3 was the strongest, while that of MNZ8 was relatively low among the strains tested. The viability rate of JJB3 was increased from 78. 12% to 99.35%, 99.48%, 99.74% in the presence of corn, soybean meal and wheat bran extracts, respectively. The extent of improvement was related to the concentration of glucose and FAN, while glucose influenced the viability greatly. As a result, the best protecting effect was provided by wheat bran extracts, subsequently by soybean meal and corn.