Aims
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).
Methods and Results
Fresh faeces were collected from four Arabian horses. The cellulose鈥恏ydrolytic 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聽<聽0路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聽<聽0路05) DM, OM, CP, NDF and ADF digestibility of WS. The highest and lowest (P聽<聽0路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聽<聽0路05) compared to control.
Conclusions
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.
Significance and Impact of the Study
Wheat straw is a major agro鈥恟esidue fed to ruminants. However, high fibre contents reduce digestibility and limit animal productivity. It seems that enhancement of ruminal degradation of these by鈥恜roducts 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.