Sustainable Fish Feeds with Insects and Probiotics Positively Affect Freshwater and Marine Fish Gut Microbiota

Abstract

Aquaculture is the fastest-growing agricultural industry in the world. Fishmeal is an essential component of commercial fish diets, but its long-term sustainability is a concern. Therefore, it is important to find alternatives to fishmeal that have a similar nutritional value and, at the same time, are affordable and readily available. The search for high-quality alternatives to fishmeal and fish oil has interested researchers worldwide. Over the past 20 years, different insect meals have been studied as a potential alternate source of fishmeal in aquafeeds. On the other hand, probiotics—live microbial strains—are being used as dietary supplements and showing beneficial effects on fish growth and health status. Fish gut microbiota plays a significant role in nutrition metabolism, which affects a number of other physiological functions, including fish growth and development, immune regulation, and pathogen resistance. One of the key reasons for studying fish gut microbiota is the possibility to modify microbial communities that inhabit the intestine to benefit host growth and health. The development of DNA sequencing technologies and advanced bioinformatics tools has made metagenomic analysis a feasible method for researching gut microbes. In this review, we analyze and summarize the current knowledge provided by studies of our research group on using insect meal and probiotic supplements in aquafeed formulations and their effects on different fish gut microbiota. We also highlight future research directions to make insect meals a key source of proteins for sustainable aquaculture and explore the challenges associated with the use of probiotics. Insect meals and probiotics will undoubtedly have a positive effect on the long-term sustainability and profitability of aquaculture.

The Replacement of Fish Meal with Poultry By-Product Meal and Insect Exuviae: Effects on Growth Performance, Gut Health and Microbiota of the European Seabass, Dicentrarchus labrax

“…The use of insects in animal feed is strictly regulated by the European Union (EU), which authorizes the use of eight insect species in feed for aquaculture, namely the common housefly (Musca domestica), the black soldier fly (Hermetia illucens), lesser mealworm (Alphitobius diaperinus), mealworm (Tenebrio molitor), house cricket (Acheta domesticus), field cricket (Gryllus assimilis), banded cricket (Gryllodes sigillatus), and silkworm (Bombyx mori). Among them, the black soldier fly and mealworm are the most used insect species in aquafeed [22,23].…”

“…In addition, the combination of BSF and PBM restored the gut microbiota of fish negatively affected by a plant-based diet by improving the richness of bacterial species and abundance of beneficial bacteria [25,26]. This prebiotic effect is principally due to chitin, the indigestible polysaccharide that makes up the exoskeleton of insects [22,27]. The addition of insect meal usually increases the amount of lactic acid bacteria (LAB) and the genus Bacillus, which are commonly used as probiotics in aquaculture.…”

Microplastics contamination in fish feeds: Characterization and potential exposure risk assessment for cultivated fish of Bangladesh

“…These species include the black soldier fly ( Hermetia illucens ), the yellow mealworm ( Tenebrio molitor ), and the common housefly (Musca domestica ) [ 86 , 87 ]. Regardless of the various techniques employed for the propagation and production of diverse species, insects have demonstrated encouraging outcomes in terms of their potential utilization as a protein and oil resource in aqua feed [ 88 ].…”

Transcriptome analysis and immune gene expression of channel catfish (Ictalurus punctatus) fed diets with inclusion of frass from black soldier fly larvae

“…Furthermore, the majority of insect larvae can grow on low-quality organic wastes so that the reuse of the remaining organic substrate results in efficient bioconversion and the larvae or prepupae can have enriched proteins, lipids, minerals, and vitamins ( Rana et al, 2015 ; Yildirim-Aksoy et al, 2020a ; Yildirim-Aksoy et al, 2020b ; Xu et al, 2021 ; Mohan et al, 2022 ). Additionally, many insect species have shown an inhibitory effect on fungal and bacterial growth such that their dietary inclusion may increase the shelf life of feed and also provide beneficial effects on the gut of fish ( Sheppard et al, 2002 ; Van Huis et al, 2013 ; Hounmanou et al, 2018 ; De Silva et al, 2019 ; Hoc et al, 2019 ; Koutsos et al, 2022 ; Hasan et al, 2023 ).…”