Effects of fermented mulberry leaves on growth, serum antioxidant capacity, digestive enzyme activities and microbial compositions of the intestine in crucian ( <i>Carassius carassius</i> )
Wenjuan Zhu, Siyuan Xiao, Siyu Chen, Qian Xu, Zheng Yang, Jing Liu, Hongquan Wang, Shile Lan
Abstract
Mulberry (Morus alba) leaves are rich in proteins, vitamins and trace elements, which serve as ingredients of feed. However, the application of mulberry leaves is limited by the anti-nutritional factors present in them. In this study, we fermented the mulberry leaves using complex microorganisms containing lactic acid bacteria and yeast and investigated the effects of feed containing 0%, 5%, 10%, 15% and 20% FMLs on growth performance, serum antioxidant capacity, digestive capacity and intestinal microbiota composition in crucian (Carassius carassius). The intestinal microbiota composition was investigated using high-throughput sequencing of 16S rRNA gene. Our results showed that adding 5% FMLs to feed promoted growth performance, serum antioxidant capacity and intestinal digestive enzyme activities of crucian. There was no significant difference between the gut microbiota composition of crucian fed 5% FMLs and the blank control. When added FMLs exceeded 10%, the growth performance, serum antioxidant capacity and intestinal digestive enzyme activities decreased, and the homeostasis of gut microbiota was destroyed. These findings indicated that addition of 5% FMLs not only significantly promoted the growth of crucian, but also improved the antioxidant capacity and digestive capacity.