山羊瘤胃内产乳酸菌的分离鉴定及其产D-、L-乳酸特性的研究

Isolation and Identification of Lactic Acid Bacteria and Characteristics of D-and L-lactate Production in Goat Rumen

为阐明瘤胃中产乳酸菌的种类及其产乳酸特性,本试验以饲喂精粗比例为6∶4的健康山羊瘤胃液为接种物,利用厌氧分离技术,经形态学和16S rRNA序列分析法,从山羊瘤胃中分离获得6株细菌(分别命名为L2、L3、L5、L8、L10和L12)。菌株主要为3类:L2、L8、L10为牛链球菌,L5为马链球菌,L3和L12为食窦魏斯氏菌。L3和L12属首次从反刍动物瘤胃中分离获得。生长曲线测定结果表明,在接种后10 h内,各菌株生长进入平台期;培养24 h后,各菌株发酵液中D-、L-乳酸测定结果显示,L3、L5、L8、L10和L12的L-乳酸浓度均在14 mmol/L以上;L3、L5和L12的D-乳酸浓度均在14 mmol/L以上,L2和L10的D-乳酸浓度分别为4.17和5.07 mmol/L,L8的D-乳酸浓度低于1 mmol/L。结果显示,在常规饲粮条件下,山羊瘤胃中主要的产乳酸菌是牛链球菌、马链球菌和食窦魏斯氏菌,且以产混合型乳酸为主。

This study was conducted to isolate the lactic acid bacteria and investigate its characteristics of lactate production in the rumen of goat.Six strains of lactic acid-producing bacteria（named L2,L3,L5,L8,L10 and L12） were isolated from the rumen contents of goats with the methods of anaerobic isolation technics,morphology and 16S RNA sequence analysis.L2,L8 and L10 were identified as Streptococcus bovi.,L5 was identified as Streptococcus equinus,and L3 and L12 were identified as Weissella cibaria.L3 and L12 were the first time isolated from the rumen to obtain.The results of growth curves showed that the strain entered a stationary phase of growth after 10 h incubation.After 24 h incubation,the concentrations of L-lactate of L3,L5,L8,L10 and L12 were all beyond 14 mmol/L;the concentrations of D-lactate of L3,L5 and L12 were all beyond 14 mmol/L;the concentrations of D-lactate of L2,L10 and L8 were 4.17,5.07 and 0.83 mmol/L,respectively.The results indicate that the Streptococcus bovis,Streptococcus equinus and Weissella cibaria are the predominant lactate producer in the rumen of goats,and they can produce both the D-and L-lactate.