Diversity and activity of cellulolytic bacteria, isolated from the gut contents of grass carp (Ctenopharyngodon idellus) (Valenciennes) fed on Sudan grass (Sorghum sudanense) or artificial feedstuffs
Diversity and activity of cellulolytic bacteria, isolated from the gut contents of grass carp (Ctenopharyngodon idellus) (Valenciennes) fed on Sudan grass (Sorghum sudanense) or artificial feedstuffs
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从以苏丹草 (Sorghum sudanense) 或人工饲料喂养的草鱼 (Ctenopharyngodon idellus) (Valenciennes) 的肠道内容物中分离出的纤维素分解细菌的多样性和活性
DOI：
10.1111/are.12478
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发表时间：
2016-01-01
影响因子：
2
通讯作者：
Wang, Guitang
中科院分区：
文献类型：
--
作者：
Li, Huan;Wu, Shangong;Wang, Guitang
草食性草鱼（Ctenopharyngodon idellus）具有很强的消化水生植物纤维素的能力，这取决于消化纤维素的细菌群落在胃肠道（GI）中产生的纤维素酶复合物。然而，仍然不确定哪些细菌类群可能积极参与食物纤维的消化。采用羧甲基纤维素、微晶纤维素和纤维二糖琼脂培养基，从饲喂苏丹草（242株）和人工饲料（257株）的草鱼肠道内容物中随机分离到499株纤维素分解菌，并对其进行了鉴定。结果表明，半数以上的菌株能降解羧甲基纤维素和纤维二糖，其余菌株仅能降解微晶纤维素。16SrDNA序列分析表明，纤维素分解菌以气单胞菌属（Aeromonas）为主，其次为肠杆菌属（Enterobacter）、肠球菌属（Enterococcus）、柠檬酸杆菌属（Citrobacter）、芽孢杆菌属（Bacillus）、拉乌尔氏菌属（Raoultella）、克雷伯氏菌属（Klebsiella）、水滑石菌属（Hydrotalea）、假单胞菌属（Pseudomonas）、短芽孢杆菌属（Brevibacillus）和一些未分类的细菌。值得注意的是，草鱼喂养的草与高纤维含量窝藏更高的多样性的纤维素分解细菌比低纤维饲料喂养的。研究结果为草鱼肠道纤维素分解菌的多样性与食物纤维含量之间存在正相关关系提供了依据。因此，改善草鱼肠道中GI纤维分解微生物的生长条件和纤维素酶活性是有效利用高纤维饲料的关键。
Herbivorous grass carp (Ctenopharyngodon idellus) has a powerful capability to digest cellulose from aquatic plants, depending on the cellulase complex produced by the cellulolytic bacterial community in the gastrointestinal (GI) tract. However, it remains uncertain which bacteria taxa may actively participate in the digestion of food fibre. In this study, a total of 499 cellulolytic bacteria from the gut content of grass carp fed on Sudan grass (242 strains) and artificial feedstuffs (257 strains) were randomly isolated and characterized using carboxymethyl-cellulose, microcrystalline cellulose and cellobiose agar media. The results showed that more than half of the isolates were capable of degrading carboxymethyl-cellulose and cellobiose, while the remaining isolates were restricted to microcrystalline cellulose decomposition, exclusively. The cellulolytic bacterial community was dominated by Aeromonas, followed by Enterobacter, Enterococcus, Citrobacter, Bacillus, Raoultella, Klebsiella, Hydrotalea, Pseudomonas, Brevibacillus and some unclassified bacteria, as revealed by 16S rDNA sequence analysis. Notably, grass carp fed on grass with high-fibre content harboured a higher diversity of cellulolytic bacteria than the ones fed on low-fibre feedstuffs. Our results provided evidence for a positive correlation between the content of food fibre and the diversity of cellulolytic bacteria in grass carp intestines. Thus, improving growth conditions and cellulase activities for GI cellulolytic microorganisms in grass carp intestines are critical for effective utilization of feedstuffs containing high fibre levels.