Alternative Feed Raw Materials Modulate Intestinal Microbiota and Its Relationship with Digestibility in Yellowtail Kingfish Seriola lalandi

Chinh Thi My Dam,Richard Smullen,Michael Salini,Abigail Elizur,Tomer Ventura,Igor Pirozzi,Mark Booth

doi:10.3390/fishes5020014

Abstract

Gut microbiota plays a crucial role in nutrient digestibility and fish health. This study aimed to investigate the effects of alternative feed raw materials on the bacterial communities in the distal intestine and its relationship with nutrient digestibility in yellowtail kingfish (YTK), Seriola lalandi. Two 4-week digestibility trials were conducted to evaluate fish meal (FM), two sources of poultry by-product meal (PBM-1 & PBM-2), blood meal (BLM), faba bean meal (FBM), corn gluten meal (CGM), soy protein concentrate (SPC) and wheat flour (WH). The nutrient digestibility value was determined using the stripping fecal collection method. Bacterial communities were characterized by high-throughput sequencing based on V3-V4 region of the 16S rRNA gene. The most abundant phylum identified in the present study was Proteobacteria. A significant change in the distal intestine was observed in fish fed diets containing CGM and BLM, characterized by a reduction of species richness and diversity. Additionally, significant correlation between nutrient digestibility and intestinal microbiota was observed. Allivibrio, Vibrio, Curvibacter, Ruminococcaceae, and Clostridium were positively correlated, whereas Ralstonia genus was negatively correlated with nutrient digestibility. This study demonstrated that intestinal microbiota could be a useful tool for evaluating the digestibility of feed raw materials; however, further culture-based study is needed to confirm this observation.

Highlights

The increasing global demand for aquatic food products for human consumption has resulted in aquaculture being a rapidly growing industry worldwide in recent decades, supplying about 47% of aquatic food in the world [1]
Our results indicated that the members of Vibrionaceae family were highly represented (> 60%) in distal intestine of fish fed diet containing fish meal (FM), PBM1, PBM2, faba bean meal (FBM), soy protein concentrate (SPC) and wheat flour (WH), while the inclusion of corn gluten meal (CGM) and blood meal (BLM) in the diet of our fish favored the high relative abundance of Enterobacteriaceae
In the present study, we found the dominance of the Ralstonia genus, where most sequences of this genus were closely related to sequences identified as Ralstonia picketti in diet containing CGM and BLM

Summary

Introduction

The increasing global demand for aquatic food products for human consumption has resulted in aquaculture being a rapidly growing industry worldwide in recent decades, supplying about 47% of aquatic food in the world [1]. The continued high reliance on fish meal (FM) in aquaculture feed has resulted in a situation that is both ecologically and economically unsustainable. The investigation of alternative feed raw materials has been required to satisfy the demand of the growing aquaculture sector. Alternative feed raw materials can be for most derived from plants or land animals, and many have potential use in aquaculture diet formulation [2,3,4,5,6]. The most commonly used alternatives are plant raw materials (i.e., soybean products, canola, rapeseed, lupin, faba bean, corn and wheat)

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