Exogenous Probiotics Improve Fermentation Quality, Microflora Phenotypes, and Trophic Modes of Fermented Vegetable Waste for Animal Feed.

Guilin Du,Baoguo Zhang,Jiping Shi,Chenyang Yuan,Zhanying Zhang,Xiangcen Liu,Zhiguo Ma,Jingxian Zhang,Mark D Harrison

doi:10.3390/microorganisms9030644

Abstract

The fermentation of leaf vegetable waste to produce animal feed reduces the environmental impact of vegetable production and transforms leaf vegetable waste into a commodity. We investigated the effect of exogenous probiotics and lignocellulose enzymes on the quality and microbial community of fermented feed (FF) produced from cabbage waste. The addition of exogenous probiotics resulted in increased crude protein (CP) content (p < 0.05), better odor (moderate organic acid and ethanol, with low ammonia-N, p < 0.05), and a lower relative abundance (RA) of pathogens (below 0.4%, p < 0.05) in FF, compared to without. With the addition of exogenous probiotics, only Pediococcus and Saccharomyces were enriched and symbiotic in FF; these were the keystone taxa to reduce the abundance of aerobic, form-biofilms, and pathogenic microorganisms, resulting in an efficient anaerobic fermentation system characterized by facultative anaerobic and Gram-positive bacterial communities, and undefined saprotroph fungal communities. Thus, inoculation of vegetable waste fermentation with exogenous probiotics is a promising strategy to enhance the biotransformation of vegetable waste into animal feed.

Highlights

Improved standards of living result in changes in the way in which horticultural products are selected for harvesting, storage, transport, and sale
Ethanol content in probiotics treatment group (PTGP) was increased on day 5 (66.3 g kg−1 dry matter (DM)) compared to CTGP
Diversity and richness were significantly lower in the PTGP group during fermentation than either CTGP or enzyme treatment group (ETGP) (p < 0.05). These results suggest that exogenous probiotics and abundant ethanol decreased the colonization of undesirable microorganisms in PTGP, which resulted in the reduced richness and diversity compared with CTGP and ETGP observed in this study

Summary

Introduction

Improved standards of living result in changes in the way in which horticultural products are selected for harvesting, storage, transport, and sale This is true of leafy vegetables such as cauliflower, white cabbage, leek, and carrots [1,2,3]. Vegetable cultivation accounts for more than 10% of major crop cultivation in China and is critical in meeting human nutritional requirements, but it generates 800 million tons of vegetable waste per annum. This vegetable waste causes environmental challenges including plant/animal pathogen propagation, atmospheric and water pollution, and greenhouse gas emissions [3,4,5,6]. Vegetable wastes are typically seasonal and have high (80 wt.%) moisture content, abundant macro- and micro-nutrients, and a relatively high pathogen load [1,7].

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Conclusion