Influence of Fermented Mulberry Leaves as an Alternative Animal Feed Source on Product Performance and Gut Microbiome in Pigs

Abstract

Mulberry leaves are rich in nutrients but contain anti-nutrient factors that hinder their digestion and absorption. Feeding animals with mulberry leaves directly could harm their health. The microbial fermentation of mulberry leaves could reduce their anti-nutritional factors’ content and improve their nutritional value. Sequencing and analyzing mulberry leaves before and after fermentation showed that fermentation increased the relative abundance of Pediococcus, Bradyrhizobium, Hydrotalea, and Rhodanobacteria, and decreased that of Enterobacter. Fermentation improved the quality of mulberry leaves by rebuilding the bacterial community. Finishing pigs were raised on fermented mulberry leaves (FML), and their carcass performance, meat quality, economic benefits, and gut microbiome were evaluated. FML had no negative impact on pig carcass performance, meat quality, and antioxidant capacity, and could somewhat improve the economic benefits. FML decreased the relative abundance of Proteobacteria in the colon and Streptococcus in the feces, and increased that of Actinobacteria (cecum, colon, feces) and Prevotella (colon). The gut core microorganisms in the FML group were mainly enriched with Actinobacteria, Bifidobacterium, Bifidobacteriaceae, Bifidobacteriales, and other beneficial microorganisms. Dietary FML reduced ammonia, indole, and skatole contents in the feces. In conclusion, FML reshaped the gut microbiota without negatively affecting pig product performance, produced cleaner waste, and improved environmental protection and sustainability, making it an attractive prospective feed for pigs.