Cellulase Interacts with Lactic Acid Bacteria to Affect Fermentation Quality, Microbial Community, and Ruminal Degradability in Mixed Silage of Soybean Residue and Corn Stover.

Chao Zhao,Lihua Wang,Xin Jiang,Yonggen Zhang,Jinshan Yang,Jingyi Lv,Guangming Ma

doi:10.3390/ani11020334

Chao Zhao, Lihua Wang + Show 5 more

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https://doi.org/10.3390/ani11020334

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Abstract

Simple SummaryThe purpose of this experiment was to investigate the effects of lactic acid bacteria (LAB) and cellulase (CE) on the fermentation quality, bacterial community and ruminal degradability of soybean residue (SR) and corn stover (CS) mixed silage. The fermentation quality, rumen degradation rate and microbial diversity of mixed storage of SR and CS were effectively improved by adding lactic acid bacteria or cellulase, and the mixed addition of LAB and CE had a better effect, increased the abundance of beneficial lactic acid bacteria and reduced the abundance of harmful microorganisms, including Rahnella. In summary, in long-term mixed silage, the effect of mixed addition of lactic acid bacteria and cellulase was better than that of single addition.The objective of this experiment was to investigate the effect of lactic acid bacteria (LAB) and cellulase (CE) on the fermentation quality, rumen degradation rate and bacterial community of mixed silage of soybean residue (SR) and corn stover (CS). The experiment adopted a single-factor experimental design. Four treatment groups were set up: the control group (CON), lactic acid bacteria treatment group (LAB), cellulase treatment group (CE) and lactic acid bacteria + cellulase treatment group (LAB + CE). Among them, the amount of added LAB was 1 × 106 CFU/g, and the amount of added CE was 100 U/g. After 56 days of mixed silage, samples were taken and analyzed, and the chemical composition, fermentation quality, rumen degradation rate and microbial diversity were determined. The results showed that the pH of each treatment group was significantly (p < 0.05) lower than that of CON, while the lactic acid and ammoniacal nitrogen contents of each treatment group were significantly higher than that of CON, with the highest contents in the LAB + CE group. The contents of DNFom (Ash-free NDF), ADFom (Ash-free ADF) and DM in the LAB + CE group were significantly lower than those in the CON group, while the content of crude protein (CP) was significantly higher than that in the CON group. The in situ effective degradation rates of DM (ISDMD), DNF (ISNDFD) and CP (ISCPD) were all significantly (p < 0.05) higher in each treatment group than in the control group. The results of principal component analysis showed that the bacterial composition of the LAB, CE and LAB + CE groups was significantly different from that of the CON group (p < 0.05). Bacterial genus level analysis showed that the content of lactic acid bacteria was significantly higher in the LAB + CE group than in the other treatment groups (p < 0.05), while the content of undesirable bacteria was significantly lower than in the other treatment groups. The results showed that the addition of Lactobacillus and/or cellulase in mixed silage of SR and CS could effectively improve the quality of mixed silage fermentation, rumen degradation rate and microbial diversity, with better results when Lactobacillus and cellulase were added together, which provides new ideas for better application of SR and CS in dairy production.

Highlights

In recent years, there has been unprecedented interest in the efficient use of agricultural byproducts, as their application can significantly reduce feed production costs and manage crop-induced environmental problems [1]
The results showed that the addition of Lactobacillus and/or cellulase in mixed silage of soybean residue (SR) and corn stover (CS) could effectively improve the quality of mixed silage fermentation, rumen degradation rate and microbial diversity, with better results when Lactobacillus and cellulase were added together, which provides new ideas for better application of SR and CS in dairy production
The high moisture content of soybean residue makes it difficult to preserve for long periods of time even with silage, making it difficult to use as animal feed [2]

Summary

Introduction

There has been unprecedented interest in the efficient use of agricultural byproducts, as their application can significantly reduce feed production costs and manage crop-induced environmental problems [1]. Corn straw fibers are not digested by animals, which makes them difficult to use as animal feed, and they are discarded directly or burned in large quantities This causes environmental pollution and leads to the underutilization of feed resources [4,5]. Mixing high-moisture SR with dry CS silage reduces the moisture content and eliminates some of the undesirable fermentation characteristics of mixed silage, such as undesirable odor and low digestibility, and these characteristics can improve some of the undesirable responses of cattle to forage [6] This approach reduces the undesirable disposal and environmental impacts of SR and CS and helps to provide low-cost and high-quality animal feed for ruminant-fed farms. The adequacy of the bacterial population is an important issue that affects the quality of silage [7]

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