Effect of Ellagic Acid on Fermentation Quality and Bacterial Community of Stylo Silage

Xuan Zou,Dandan Chen,Peng Zheng,Hongjian Lv,Qing Zhang

doi:10.3390/fermentation7040256

Abstract

This study was conducted to investigate the effect of ellagic acid on the bacterial community and fermentability of stylo silage. Three treatments of stylo silage were used: control (CK) and treated with 1% or 2% ellagic acid (EA1 and EA2) on a fresh matter basis. All silage was stored at ambient temperature and opened on days 3, 7, 14, and 30. Fermentation characteristics, protein fraction, and bacteria community of all periods of silage were analyzed. Results showed that dry matter and crude protein content were increased, and pH value, number of coliform bacteria, contents of acetic acid, and ammonium nitrogen were decreased with the addition of ellagic acid. The antioxidant activity of 1% and 2% ellagic acid treated silages was significantly higher than the control. Meanwhile, the relative abundance of Klebsiella and Clostridium was decreased with the addition of ellagic acid, and the abundance of Lactobacillus, Weissella, and Enterococcus was increased with prolonged days of ensiling. Adding ellagic acid to stylo silage could improve the fermentation quality and preservation of protein, and reduce the abundance of harmful bacteria.

Highlights

This study was conducted to investigate the effect of ellagic acid on the bacterial community and fermentability of stylo silage
The dry matter of fresh stylo was 34.3%, which was relatively high compared with the findings of He et al [22], and it reached the ideal dry matter content (30–35%) for good silage [2]
A higher proportion of TP indicates better nutritional value of the protein given that non-protein nitrogen (NPN) is less efficiently utilized in ruminants relative to true protein [22]

Summary

Introduction

This study was conducted to investigate the effect of ellagic acid on the bacterial community and fermentability of stylo silage. Stylo (Stylosanthes guianensis Sw.), known as pencilflower, a common flowering legume that is native to South America, grows mainly in tropical and subtropical regions In the subtropics, it is considered an important feed source for ruminants, with high yields, high nutrient levels, and wide adaptability [5]. Silage quality is affected by many factors, legumes like stylo are difficult to ensile directly without additives because of their high buffering capacity, low water-soluble carbohydrate content, and high dry matter content [7,8]. Undesirable microorganisms such as Clostridia and Enterobacter are always present in legume silage during ensiling, which leads to butyric acid accumulation and proteolysis [9]. Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations

Methods

Results

Conclusion