The potential and effects of saline-alkali alfalfa microbiota under salt stress on the fermentation quality and microbial

Duo Wen Sa,Lin Sun,Qiang Lu,Zhen Wang,Gentu Ge,Yushan Jia

doi:10.1186/s12866-021-02213-2

Abstract

BackgroundThe objective of this study was to evaluate the chemical compositions and microbial communities of salt-tolerant alfalfa silage. Salt-tolerant alfalfa was ensiled with no additive control, and cellulase for 30 and 60 to 90 days. In this study, the dry matter (DM) content of the raw material was 29.9% DM, and the crude protein (CP) content of the alfalfa was 21.9% CP.ResultsAfter 30 days of fermentation, the DM content with the cellulase treatment was reduced by 3.6%, and the CP content was reduced by 12.7%. After 60 days of fermentation, compared with alfalfa raw material, the DM content in the control group (CK) was reduced by 1%, the CP content was reduced by 9.5%, and the WSC (water-soluble carbohydrates) content was reduced by 22.6%. With the cellulase, the lactic acid content of the 30- and 60-day silages was 2.66% DM and 3.48% DM. The content of Firmicutes in salinized alfalfa raw material was less than 0.1% of the total bacterial content. Before and after ensiling, the microbes had similar composition at the phylum level, and were composed of Firmicutes, Actinobacteria, Bacteroidetes, and Proteobacteria. The abundance of Pantoea was dominant in fresh alfalfa. In the absence of additives, after 30 days and 60 days of silage, the dominant lactic acid bacteria species became Lactococcus and Enterococcus.ConclusionsThe results showed that LAB (Lactobacillus, Lactococcus, Enterococcus, and Pediococcus) played a major role in the fermentation of saline alfalfa silage. It also can better preserve the nutrients of saline alfalfa silage. The use of cellulase enhances the reproduction of Lactobacillus. The fermentation time would also change the microbial community of silage fermentation.

Highlights

The objective of this study was to evaluate the chemical compositions and microbial communities of salt-tolerant alfalfa silage
Alfalfa is showing high salt tolerance to saline-alkali soil and appropriate salt stress would improve the quality of alfalfa, including amino acids, proteins, and other important nutrients [5, 6]
Given the need to make full use of salinized land resources and expand the forage sources, the purpose of the study was to investigate the influence of time and additives on salttolerant alfalfa fermentation characteristics and the bacterial community of silage, to improve the quality of alfalfa under salinization

Summary

Introduction

The objective of this study was to evaluate the chemical compositions and microbial communities of salt-tolerant alfalfa silage. It has become increasingly important to obtain more protein feed from limited land resources. Salinized soil resources were distributed in more than 100 countries around the world, and there is a global salinized land area of 955 million hm2 [2]. Soil salinization is an issue affecting the development of global agriculture and animal husbandry. Alfalfa [Medicago sativa L.] has high levels of crude protein, digestible nutrients, minerals [3]. Alfalfa is showing high salt tolerance to saline-alkali soil and appropriate salt stress would improve the quality of alfalfa, including amino acids, proteins, and other important nutrients [5, 6].

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