Effects of Citric Acid and Lactobacillus plantarum on Silage Quality and Bacterial Diversity of King Grass Silage.

Xuejuan Zi,Renlong Lv,Yeyuan Chen,Jun Tang,Hanlin Zhou,Mao Li

doi:10.3389/fmicb.2021.631096

Abstract

To better understand the mechanism underlying the citric acid (CA)-regulated silage fermentation, we investigated the bacterial community and fermentation quality of king grass (KG) ensiled without (CK) or with Lactobacillus plantarum (L), CA and the combination of L and CA (CAL). The bacterial community was characterized by using the 16Sr DNA sequencing technology. The L and CA treatments altered the silage bacterial community of KG, showing reduced bacterial diversity, while the abundance of desirable genus Lactobacillus was increased, and the abundances of undesirable genus Dysgonomonas and Pseudomonas were decreased. The additives also significantly raised the lactic acid content, dropped the pH, and reduced the contents of acetic acid, propionic acid, and ammonia-N in ensiled KG (P < 0.01). Besides, the combination treatment was more effective on silage fermentation with the highest pH and lactic acid content, while the contents of acetic acid, propionic acid, and ammonia-N were the lowest (P < 0.01). Moreover, CAL treatment exerted a notable influence on the bacterial community, with the lowest operational taxonomic unit (OTU) number and highest abundance of Lactobacillus. Furthermore, the bacterial community was significantly correlated with fermentation characteristics. These results proved that L and CA enhanced the KG silage quality, and the combination had a beneficial synergistic effect.

Highlights

As a Pennisetum grass species, king grass (Pennisetum purpureum Schumacher × P. glaucum (Linnaeus) R
To further investigate the effects of additives on the bacterial community during ensiling, we examined the bacterial structures of king grass (KG) silage at the genus level (Figure 3 B)
The positive effect of citric acid (CA) on forage chemical composition has been reported in previous studies (Li et al, 2016; Ke et al, 2017, 2018; He et al, 2019b). These results suggested that a combination of L. plantarum and CA could improve the feeding value of KG to some extent

Summary

Introduction

As a Pennisetum grass species, king grass (Pennisetum purpureum Schumacher × P. glaucum (Linnaeus) R. KG) is widely distributed in the tropical and subtropical regions worldwide (Zhao et al, 2019). KG is a multifunctional plant, and it is extensively used in ecological environmental protection, bioenergy industry, and animal husbandry (Li et al, 2014; Li M. et al, 2019). KG vigorously grows in the summer or rainy season. Its growth lags in the winter or drought season, resulting in biomass shortages (Li et al, 2014). Due to its seasonal harvest, KG should be properly preserved to provide a continuous supply. Ensiling is an approach for the longterm preservation of green forage. It is hard to make high-quality silage since KG or other

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Discussion

Conclusion