Changes in the intestine microbial, digestion and immunity of Litopenaeus vannamei in response to dietary resistant starch

Yafei Duan,Yun Wang,Hua Li,Hongbiao Dong,Jiasong Zhang,Qingsong Liu,Dalin Xiong

doi:10.1038/s41598-019-42939-8

Abstract

Resistant starch (RS) is a constituent of dietary fibre that has beneficial effects on the intestine physiological function of animals. However, the roles of RS on shrimp intestine health is unknown. In this study, we investigated the the effects of dietary RS on the microbial composition, and digestive and immune-related indices in the intestine of Litopenaeus vannamei. The shrimp were fed with diets containing different levels of RS: 0 g/kg (Control), 10 g/kg (RS1), 30 g/kg (RS2) and 50 g/kg (RS3) for 56 days. The results showed that dietary RS improved the morphology of the intestine mucosa. RS also increased the activity of digestive enzymes (AMS, LPS, Tryp, and Pep) and immune enzymes (PO, T-AOC, T-NOS, and NO), and the expression levels of immune-related genes (proPO, ALF, Lys, HSP70, Trx, Muc-1, Muc-2, Muc-5AC, Muc-5B, and Muc-19). A microbiome analysis indicated that dietary RS increased the short-chain fatty acids (SCFAs) contents and altered the composition of the intestine microbial. Specifically, RS increased the abundances of Proteobacteria and decreased the abundance of Bacteroidetes. At the genus level, the beneficial bacteria (Lutimonas, Ruegeria, Shimia, Mesoflavibacter, and Mameliella) were enriched, which might be involved in degrading toxins and producing beneficial metabolites; while potential pathogens (Formosa and Pseudoalteromonas) were decreased in response to dietary RS. Our results revealed that dietary RS could improve the intestine health of L. vannamei, probably via modulating the intestine microbial composition and SCFAs contents, and enhancing the digestion and immunity of the shrimp.

Highlights

The intestine microbial has a mutual relationship with its host which influences the digestibility, metabolism, and immunity of the host[1,2]
The total nitric oxide synthase (T-NOS) activity was highest in the RS3 group (P < 0.05), and there were no differences between the RS1 and RS2 groups
The intestine health influences the shrimp health because intestine mucosa provides an important barrier to pathogens

Summary

Introduction

The intestine microbial has a mutual relationship with its host which influences the digestibility, metabolism, and immunity of the host[1,2]. The production of SCFAs occurs mainly through the bacterial fermentation of fibre that non-digestible by the gastrointestinal systems of animals[7]. Dietary interventions, especially via supplementation with fiber, are efficient for regulation of the intestinal microbial, will be beneficial to the host health. As a constituent of dietary fibre, resistant starch (RS) is non-digestible in the intestine of animals but can be fermented by resident microbial[9]. Diets that are rich in RS have beneficial effects to animal health, especially produce SCFAs by microbial fermentation, which can acidify the intestine environment, modify and stabilize intestine microbial[10]. In this study, we explored the effects of dietary RS on the intestine health of L. vannamei, in terms of intestine histological structure, the digestive and immune indices, and the intestine microbial composition and metabolite SCFAs contents

Methods

Results

Conclusion