Department of Animal Science, Faculty of Animal Science and Food Technology, Agricultural Sciences and Natural Resources University of Khuzestan, Mollasani, Ahvaz, Iran.
Department of Biology, Faculty of Science, Shahid Chamran University of Ahvaz, Khuzestan, Iran.
J Appl Microbiol. 2019 Aug;127(2):344-353. doi: 10.1111/jam.14251. Epub 2019 Jun 7.
This study was conducted to isolate and identify the cellulolytic bacteria from gastrointestinal tract of Arabian horse and investigate their effect on the nutritional value of wheat straw (WS).
Fresh faeces were collected from four Arabian horses. The cellulose-hydrolytic bacteria were isolated by using a medium amended with carboxymethyl cellulose (CMC). The activity of CMC was determined by measuring the release of reducing sugars from CMC. Among the isolates, four isolates (L11, L12, L2 and Z2) showed maximum hydrolysis capacity. 16S rRNA sequence analysis showed that these isolates possessed 99, 99, 99 and 98% similarity with Paenibacillus polymyxa, Paenibacillus polymyxa, Enterobacter cloacae and Escherichia coli respectively. Wheat straw was incubated with the isolated bacteria in liquid medium. Disappeared dry matter (DM) and crude protein (CP), neutral detergent fibre (NDF), indigestible NDF (iNDF) and acid detergent fibre (ADF) contents of WS were affected by microbial treatments (P < 0·05). The highest disappearance of DM and CP contents and the lowest NDF, iNDF and ADF contents of WS were observed by treating with P. polymyxa L11. The values of NDF, iNDF and ADF were the highest and CP was the lowest in control. Gas production parameters and digestibility of processed samples were determined. Bacterial treatments enhanced (P < 0·05) DM, OM, CP, NDF and ADF digestibility of WS. The highest and lowest (P < 0·05) DM, OM, CP, NDF and ADF digestibilities were observed for WS treated with isolates L12 and control respectively. Potential of gas production (b), truly degraded organic matter (TDOM) and microbial biomass of bacteria treatments were significantly higher (P < 0·05) compared to control.
Generally, the results of this study showed that the isolated bacteria from horse faeces are capable of changing the chemical composition, increasing digestibility as well as enhancing nutrition value of WS.
Wheat straw is a major agro-residue fed to ruminants. However, high fibre contents reduce digestibility and limit animal productivity. It seems that enhancement of ruminal degradation of these by-products is necessary. The results of this study revealed that cellulolytic bacteria isolated from gastrointestinal tract of horse can be used for biological treatment of WS.
本研究旨在从阿拉伯马胃肠道中分离并鉴定出纤维素分解菌，并研究其对小麦秸秆（WS）营养价值的影响。
从四匹阿拉伯马中采集新鲜粪便。通过使用添加羧甲基纤维素（CMC）的培养基从粪便中分离出纤维素水解菌。通过测量从 CMC 释放的还原糖来测定 CMC 的活性。在分离株中，L11、L12、L2 和 Z2 四个分离株显示出最大的水解能力。16S rRNA 序列分析表明，这些分离株与多粘类芽孢杆菌、多粘类芽孢杆菌、阴沟肠杆菌和大肠杆菌的相似度分别为 99%、99%、99%和 98%。将分离的细菌在液体培养基中与小麦秸秆共培养。微生物处理（P<0.05）影响 WS 的消失干物质（DM）和粗蛋白（CP）、中性洗涤纤维（NDF）、不可消化 NDF（iNDF）和酸性洗涤纤维（ADF）含量。用多粘类芽孢杆菌 L11 处理 WS 时，DM 和 CP 含量的消失率最高，NDF、iNDF 和 ADF 含量最低。对照中 NDF、iNDF 和 ADF 含量最高，CP 含量最低。测定处理后样品的产气量参数和消化率。细菌处理（P<0.05）提高了 WS 的 DM、OM、CP、NDF 和 ADF 消化率。L12 处理和对照的 WS 的 DM、OM、CP、NDF 和 ADF 消化率最高和最低（P<0.05）。与对照相比，细菌处理的产气量（b）、真正降解的有机质（TDOM）和细菌微生物生物量显著更高（P<0.05）。
一般来说，本研究结果表明，从马粪便中分离出的细菌能够改变 WS 的化学成分，提高其消化率，增强其营养价值。
小麦秸秆是反刍动物的主要农业残余物。然而，高纤维含量会降低消化率并限制动物生产力。似乎有必要增强这些副产品在瘤胃中的降解。本研究结果表明，从马胃肠道中分离出的纤维素分解菌可用于 WS 的生物处理。
