Production performance, nutrient digestibility, serum biochemistry, fillet composition, intestinal microbiota and environmental impacts of European perch (Perca fluviatilis) fed defatted mealworm (Tenebrio molitor)

Hung Quang Tran,Markéta Prokešová,Mahyar Zare,Jan Matoušek,Ilario Ferrocino,Laura Gasco,Vlastimil Stejskal

doi:10.1016/j.aquaculture.2021.737499

Hung Quang Tran, Markéta Prokešová + Show 5 more

Open Access

https://doi.org/10.1016/j.aquaculture.2021.737499

Copy DOI

Abstract

Yellow mealworm (Tenebrio molitor) larvae meal (TM), one of the seven insect species approved for use in aquafeed in Europe, is a frequently investigated candidate for fish diets. This study aimed to investigate the effects of dietary defatted TM on production performance, serum biochemistry, nutrient digestibility, fillet traits, intestinal microbiota, and environmental impacts of perch (Perca fluviatilis). Four experimental diets, characterized by defatted TM inclusion levels of 0, 6.8, 13.5 and 20.3%, respectively, or 0, 25, 50, and 75% replacement for fishmeal on a w/w basis (TM0, TM25, TM50, and TM75, respectively), were fed to juvenile perch (bodyweight 20.81 ± 3.36 g, total length 117.7 ± 7.2 mm) (quadruplicated per diet) for 105 days. Inclusion levels of 6.8% or 25% fishmeal replacement by defatted TM did not show a significant effect on specific growth rate and feed conversion ratio, while further levels of 13.5 and 20.3%, or 50 and 75% fishmeal replaced by defatted TM, respectively, displayed a significant delay in the former (P = 0.01), but increase in the latter indice (P = 0.04) compared to TM0 diet. The aspartate aminotransferase activities in perch's serum increased with increasing dietary TM (P = 0.02). Protein digestibility of perch exhibited a negative correlation with dietary TM (P = 0.03). Dietary defatted TM did not, alter fillet composition of perch (P > 0.05) and modify diversity of fish gut microbiota (Chao1 index, P = 0.742; Shannon index, P = 0.557; and observed species, P = 0.522), but significantly reduced abundance of Lactobacillus (P = 0.04) and Streptococcus (P = 0.01). Diets containing more than 6.8% TM generated a comparable amount of total solid waste and solid phosphorus waste as the TM0, whereas solid nitrogen waste significantly increased with elevated TM levels (P < 0.001). The estimated environmental impacts of perch fed TM25 were comparable to TM0 for global warming potential, acidification, and land use (P > 0.05), whereas TM50 and TM75 exerted heavier burdens on energy use, eutrophication, and water use than TM0 (P < 0.001). Fishmeal replacement by TM significantly reduced the economic fish-in fish-out ratio (P < 0.001). Results of this multidisciplinary study revealed important considerations for formulating diets with insect meals and their potential effects on fish performance and environmental impacts.

Highlights

The increasing use of alternative aquafeed ingredients for fishmeal (FM) and fish oil is necessary to ensure the sustainability of the aquaculture sector [1]
We investigated the environmental consequence of dietary insect meal (T. molitor) in perch aquafeeds, concerning solid waste output, environmental impact associated with one kg of perch produced, and economic fish-in fish-out (eFIFO), which has been considered as an important proxy for environmental sustainability of aquaculture sector [26, 27, 44]
The present study highlighted the possibility of using defatted insect meal (T. molitor) in the diets of European perch (P. fluviatilis), an emerging, potential aquaculture candidate in Europe

Summary

Introduction

The increasing use of alternative aquafeed ingredients for fishmeal (FM) and fish oil is necessary to ensure the sustainability of the aquaculture sector [1]. The limitations associated with specific unfavorable nutritional components [4], and the environmental consequences of product intensification, especially the increasing demand for arable land - the immense pressures on the planet [5, 6], could hamper their expanding use in aquafeeds. Fishery and aquaculture by-products, together with insect meal, represent the most excellent protein sources to satisfy the aquafeed demand in the coming years [7, 8]. Insect meal has become a sustainable protein source for livestock and aquaculture production due to its favorable nutritional values [10], health benefits for the fed organisms [11], lower environmental impacts associated with land and water resource demand than that of plant proteins [12, 13], and positive effects on the aquatic environment than an FM-based diet [14]. Yellow mealworm (Tenebrio molitor) larvae meal (TM), one of seven approved insect species used in aquafeeds, is a frequently investigated candidate for fish diets

Objectives

Methods

Results

Discussion

Conclusion