Integrative Metabolomics for Assessing the Effect of Insect (Hermetia illucens) Protein Extract on Rainbow Trout Metabolism

Simon Roques,Annick Moing,Daniel Jacob,Nadège Richard,Yann Marchand,Benoit Fauconneau,Sandrine Skiba-Cassy,Laurence Guimas,Catherine Deborde

doi:10.3390/metabo10030083

Abstract

Nutrition of high trophic species in aquaculture is faced with the development of sustainable plant-based diets. Insects seem particularly promising for supplementing plant-based diets. However, the complex effect of whole insect meal on fish metabolism is not well understood, and even less is known about insect meal extracts. The purpose of this work was to decipher the metabolic utilization of a plant-based diet supplemented with the gradual addition of an insect protein extract (insect hydrolysate at 0%, 5%, 10% and 15%). 1H-NMR profiling was used to assess metabolites in experimental diets and in fish plasma, liver and muscle. A significant dose-dependent increase in growth and feed efficiency with increasing insect extract amounts was observed. The incremental incorporation of the insect extract in diet had a significant and progressive impact on the profile of dietary soluble compounds and trout metabolome. The metabolites modulated by dietary insect extracts in plasma and tissues were involved in protein and energy metabolism. This was associated with the efficient metabolic use of dietary free amino acids toward protein synthesis through the concomitant supply of balanced free amino acids and energy substrates in muscle. The findings provide new insights into how the dietary food metabolome affects fish metabolism.

Highlights

Fish meal (FM) will no longer be sustainable for aquaculture in the foreseeable future because it is produced from limited stocks of pelagic fish, while the amount of feed used for farmed fish continues to increase [1]
Supplementation of the plant-based (PB) diet with the insect extract had a positive and significant effect on fish final body weight (ANOVA, P-value = 4.10−4 ) with a progressive increase in final body weight depending on the amount of insect extract (INS)
The final body weight of fish fed the diet with 5% of insect extract (INS05) was not significantly different from that of the PB diet and the same was observed between fish fed the INS10 and INS15 diets

Summary

Introduction

Fish meal (FM) will no longer be sustainable for aquaculture in the foreseeable future because it is produced from limited stocks of pelagic fish, while the amount of feed used for farmed fish continues to increase [1]. The addition of H. illucens larvae in fish feed composition already gives encouraging results on growth performance and is a good nutritional alternative to FM [4,5,6,7]. It has a high protein content, ranging from 40% to 63% of the total biomass depending on the rearing substrate [8], and an adequate amino acid profile quite similar to that of FM, especially regarding sulfur amino acids and lysine, which are limiting in most plant protein ingredients [9]. Teleosts can benefit of the direct absorption of small peptides in the larval stage and in the later stages, especially through the PepT1 transporter, which is activated during refeeding after a fasting state to ensure compensatory growth as compared to mammals and birds [14,15]

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