Abstract
Innovative fish diets made of terrestrial plants supplemented with sustainable protein sources free of fish-derived proteins could contribute to reducing the environmental impact of the farmed fish industry. However, such alternative diets may influence fish gut microbial community, health, and, ultimately, growth performance. Here, we developed five fish feed formulas composed of terrestrial plant-based nutrients, in which fish-derived proteins were substituted with sustainable protein sources, including insect larvae, cyanobacteria, yeast, or recycled processed poultry protein. We then analyzed the growth performance of European sea bass (Dicentrarchus labrax L.) and the evolution of gut microbiota of fish fed the five formulations. We showed that replacement of 15% protein of a vegetal formulation by insect or yeast proteins led to a significantly higher fish growth performance and feed intake when compared with the full vegetal formulation, with feed conversion ratio similar to a commercial diet. 16S rRNA gene sequencing monitoring of the sea bass gut microbial community showed a predominance of Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes phyla. The partial replacement of protein source in fish diets was not associated with significant differences on gut microbial richness. Overall, our study highlights the adaptability of European sea bass gut microbiota composition to changes in fish diet and identifies promising alternative protein sources for sustainable aquafeeds with terrestrial vegetal complements.
Highlights
Aquaculture is the fastest growing animal-food producing sector, supplying over half of fish and seafood for human consumption [1]
The four other feed formulas were composed of approximately 85% vegetal feed (VEG) and 15% experimental alternatives proteins sources: cyanobacterium (Arthrospira platensis, SPI), processed animal protein composed by a mix of poultry blood meal and hydrolyzed poultry feathers (PAP), yeast protein fraction from Saccharomyces cerevisiae (YEA) (Nutrisaf® 503, Phileo by Lesaffre, France), and an hydrolyzed insect larvae meal
insect larvae (INS) and YEA final body weight was significantly higher than PAP (p < 0.01), itself higher than VEG (p < 0.001), in turn significantly higher than SPI, which had tMhiecrlooorwgaensitsmbso2d0y20w, 8e, xigFhOtR(pPEGvdf9lieosa7srhwin.ym9dse%oiurSlf,argPaivrnrIitogdvdowraiiooceltawtthrhstai)tepnthlreegesdrtdrfnwioeetonortesmndrleaoeasfgw>ntiame9cetr7erii.vd,l9gawea%rryoiimt,tw2ohi8nptoehda(tvFcihpceitegaenorrutnifsdrnooeoigrme2mvtn,eesaoprnana
Summary
Aquaculture is the fastest growing animal-food producing sector, supplying over half of fish and seafood for human consumption [1]. Marine algae, yeast, and alternative animal proteins, including insects, are currently considered as new protein sources, their impact on fish gut microbiota, intestine health, and growth performance are not yet fully known [7,8,9,10]. Previous studies have shown that partially substituting fishmeal by terrestrial plant protein extract alone or in combination with vegetal oils does not affect European sea bass survival and growth performance [4,12,13,14,15,16,17]. Proteins from poultry, brewer’s yeast (Saccharomyces cerevisiae), larvae insect meal (Hermetia illucens and Tenebrio molitor), or microalgae were reported to advantageously replace up to 76% of fishmeal without significantly impacting European sea bass performance [21,22,23,24,25,26]. Data concerning the effects of fishmeal substitution on sea bass gut microbiota are scarce, and only focused on partial replacement of fishmeal by alternative protein sources [4,27]
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