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Screening of Alkali-Resistant Cellulolytic Bacteria for Improving the Nutritional Value of Ammoniated Wheat Straw: Identification of Optimal Strain and Storage Duration
by
, ,
Guofang Chen
1, 
Haichao Yan
1,
Jiawei Lu
1,
Luyao Zhang
2,
Qiang Liu
1,
Cong Wang
1,
Gang Guo
1,
Lei Chen
1 and
Wenjie Huo
1,* 1
College of Animal Sciences, Shanxi Agricultural University, 1 Minxian Street, Jinzhong 030801, China
2
Heilongjiang Animal Husbandry General Station, 243 Haping Road, Xiangfang District, Harbin 150069, China
*
Author to whom correspondence should be addressed.
Animals 2026, 16(14), 2138; https://doi.org/10.3390/ani16142138
Submission received: 4 June 2026
/
Revised: 23 June 2026
/
Accepted: 8 July 2026
/
Published: 9 July 2026
(This article belongs to the Section Animal Nutrition)
Simple Summary
Wheat straw is an abundant and low-cost feed resource for ruminants, but its high fiber content limits its digestibility. Treating straw with ammonia helps break down some of these fibers. In this study, we added five different types of alkali-resistant, fiber-degrading bacteria to ammoniated wheat straw and stored them for up to 21 days. We found that these bacterial additives further improved the nutritional value of straw by breaking down more structural carbohydrates. This led to better digestibility and increased energy availability (volatile fatty acids) during lab-simulated rumen fermentation, although it also resulted in higher methane production. The best results were achieved by adding the Bacillus pumilus strain S87 and storing for only 7 days. This work provides an effective, low-cost biological strategy to upgrade agricultural by-products like wheat straw into a higher-quality feed, although the trade-off between improved digestibility and increased methane production warrants further investigation for environmental sustainability.
Abstract
Wheat straw (WS) is an abundant crop residue with considerable potential as a ruminant feed; however, its utilization is severely constrained by a recalcitrant lignocellulosic structure. This study evaluated the effects of five alkali-resistant cellulolytic bacterial inoculants on the structural carbohydrate composition and in vitro ruminal fermentation characteristics of ammoniated wheat straw. A 6 × 3 factorial arrangement was employed, with six treatments (ammoniated WS as a control and five cellulolytic bacterial strains: X67, C72, S87, D100, and X107) and three storage durations (7, 14, and 21 days). The results showed that the bacterial treatments caused moderate losses of dry matter (DM), neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose, and cellulose at 7 and 14 days. The X107 treatment exhibited the lowest hemicellulose content, 2.1% lower than the ammoniated control. After 48 h of in vitro incubation, all bacterial treatments significantly increased potential gas production, 48 h methane production, in vitro DM digestibility (IVDMD), and in vitro NDF digestibility (IVNDFD). The S87 treatment achieved the highest IVDMD and IVNDFD, exceeding the ammoniated control by 14.9% and 32.5%, respectively, at 7 days (p < 0.05). All bacterial treatments maintained relatively high total volatile fatty acid (VFA) concentrations. Furthermore, the bacterial treatments increased the relative proportions of ruminal cellulolytic microbes at 7 and 14 days. By 21 days, no significant differences were observed in DM loss or microbial proportions among treatments. These findings indicate that the application of cellulolytic bacterial additives, with appropriate selection of bacterial strain and storage duration, exerts synergistic positive effects on the feeding value of alkali-pretreated wheat straw. The S87 treatment with a 7-day storage duration proved most effective.
