Fishmeal Replacement with Hermetia illucens Meal in Aquafeeds: Effects on Zebrafish Growth Performances, Intestinal Morphometry, and Enzymology

Letizia Brogi,Mahanama De Zoysa,Rosario Licitra,Francesca Abramo,Vincenzo Miragliotta,Francesca Coppola,Simona Sagona,Carlo Bibbiani,Baldassare Fronte,Lucia Casini

doi:10.3390/fishes6030028

Abstract

Fishmeal (FM) is still the most important protein source in aquafeeds. However, due to the reduction of wild fish stocks used for FM production, its manufacturing it is now unsustainable. Insect meal represents a valid alternative to FM, due to the low carbon footprint of its production and its high nutritional value. The aim of this study was to investigate the potentials of replacing FM with black soldier fly (Hermetia illucens) meal (HIM) in aquafeeds, using zebrafish as the animal model. Four diets were formulated with increasing HIM/FM replacement rate (the control diet contained 20% FM). Mortality rates, growth performances, and feed consumptions were measured, and fish intestine samples were collected for histological and enzymatic analysis. After 49 days, all groups almost tripled their initial body weight (cumulative body weight gain ranged between 143.9 and 155.2 mg), and no statistically significant differences among treatments were observed in relation to growth performances and histological traits. Contrarily, trypsin, alkaline phosphatases, and alpha amylase–glucoamylase activities were significantly reduced when the FM replacement rate was increased. In conclusion, HIM may represent an alternative to FM, since no adverse effects were observed when it was included up to 20% in the zebrafish diet, even when replacing 100% of the FM.

Highlights

Fishmeal (FM) is still one of the most important protein source in aquafeeds, especially for carnivorous fishes and crustaceans [1]
Due to the reduction of wild fish stocks used for FM production, its manufacturing it is no longer sustainable [2,3]
No alterations of fish feeding behavior were observed during the experimental period, and the diets containing Hermetia illucens meal (HIM) were macroscopically similar to that containing FM and not HIM

Summary

Introduction

Fishmeal (FM) is still one of the most important protein source in aquafeeds, especially for carnivorous fishes and crustaceans [1]. FM in aquafeeds has been replaced mainly with vegetable ingredients such as cereals and legumes [1], and several studies have reported that FM can be successfully partially replaced by plant sources [4,5,6] These ingredients are often characterized by unbalanced amino acid profiles, low palatability, presence of anti-nutritional factors, and limited digestibility rates [7,8], with these impairing fish growth and welfare when used to fully replace FM. In this context, insect meal may represent a valid alternative protein source due to its reduced carbon footprint and its high nutritional value [9]. Since July 2017, an EU regulation has allowed the use of insect meal in aquafeeds

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Conclusion