益生乳酸菌Lactobacillus casei Zhang和Lactobacillus plantarum P8对全价饲料pH及微生物类群变化的研究

Beneficial Lactobacillus casei and Lactobacillus plantarum P8 on the Influence and Changes of pH and Microbial Groups in Complete Feed

研究了益生乳酸菌干酪乳杆菌Zhang(Lactobacillus casei Zhang)和植物乳杆菌P8(Lactobacillus planta-rum P8)对全价饲料pH及微生物类群变化的影响。分别将L.casei Zhang、L.plantarum P8单一菌种及复合菌种(11)以6.30 lg cfu/g的接种总量发酵全价饲料,测定25℃10 d发酵期间全价饲料pH和微生物类群的变化,应用选择培养基测定发酵饲料中的乳酸菌及杂菌(酵母菌、霉菌、大肠菌群、芽胞杆菌和梭状芽胞杆菌)的动态变化,应用RT-PCR技术测定试验组中的L.casei Zhang和L.plantarum P8的动态变化。结果显示,试验组pH下降显著,发酵10 d时,L.casei Zhang、L.plantarum P8单一菌种和复合菌种发酵饲料的pH分别为4.23、4.24和4.22,显著低于对照组(P<0.05);L.casei Zhang、L.plantarum P8单一菌种和复合菌种发酵饲料中的L.casei Zhang、L.plantarum P8活菌数分别为8.91、8.89、6.58和8.69 lg cfu/g。发酵期间,试验组中酵母菌、霉菌、大肠菌群、芽胞杆菌及梭状芽胞杆菌活菌数显著低于对照组(P<0.05),其中L.plantarum P8单一菌种发酵和复合菌种发酵对杂菌抑制效果显著优于L.casei Zhang单一菌种发酵(P<0.05)。结果表明,全价饲料经L.casei Zhang、L.plantarum P8发酵可以显著降低其pH,抑制其中杂菌的生长,同时L.casei Zhang、L.plantarum P8在饲料中具有良好的稳定性。

The influence of changes of Lactobacillus casei and Lactobacillus plantarum P8 on pH and microbial groups in complete feed were investigated.L.casei and L.plantarum P8 were inoculated alone or mixed（1：1） with 6.30 lg cfu/g of total inoculation volume to ferment complete feed.The changes of pH and microbial groups in complete feed were monitored during ten days fermentation at 25 ℃.The dynamic changes of lactobacteria and sundry microbes（yeasts,moulds,E.coli,Bacillus,and Clostridium） were determined using selective media;as well as the dynamic changes of L.casei and L.plantarum P8 with RT-PCR.The results showed that the pH of the tested groups decreased noticeably,10 days after the fermentation,the pH of fermented feed that inoculated with L.casei and L.plantarum P8 alone and mixed were at 4.23,4.24 and 4.22,respectively,significantly lower（P〈0.05） than the control groups.The active numbers of L.casei and L.plantarum P8 in fermented feed with single and mixed were 8.91,8.89 lg,6.58,and 8.69 lg cfu/g respectively.During the fermentation,the active number of yeasts,moulds,E.coli,Bacillus,and Clostridium were significantly lower than the control group（P〈0.05）.Among them the inhibition against sundry microbes fermented with L.plantarum alone significantly outwent L.casei.Therefore,the results indicated that the pH and the growth of sundry microbes in complete feed could be significantly reduced and inhibited by fermentation with L.casei and L.plantarum P8.At the same time L.casei and L.plantarum P8 possesses fine stability in feed.