Possible Dietary Effects of Insect-Based Diets across Zebrafish (Danio rerio) Generations: A Multidisciplinary Study on the Larval Phase

Abstract

Insects represent a valuable and sustainable alternative ingredient for aquafeed formulation. However, insect-based diets have often highlighted controversial results in different fish species, especially when high inclusion levels were used. Several studies have demonstrated that nutritional programming through parental feeding may allow the production of fish better adapted to use sub-optimal aquafeed ingredients. To date, this approach has never been explored on insect-based diets. In the present study, five experimental diets characterized by increasing fish meal substitution levels with full-fat Black Soldier Fly (Hermetia illucens; BSF) prepupae meal (0%, 25%, 50%, 75% and 100%) were used to investigate the effects of programming via broodstock nutrition on F1 zebrafish larvae development. The responses of offspring were assayed through biometric, gas chromatographic, histological, and molecular analyses. The results evidenced that the same BSF-based diets provided to adults were able to affect F1 zebrafish larvae fatty acid composition without impairing growth performances, hepatic lipid accumulation and gut health. Groups challenged with higher BSF inclusion with respect to fish meal (50%, 75% and 100%) showed a significant downregulation of stress response markers and a positive modulation of inflammatory cytokines gene expression. The present study evidences that nutritional programming through parental feeding may make it possible to extend the fish meal substitution level with BSF prepupae meal in the diet up to almost 100% without incurring the well-known negative side effects of BSF-based diets.

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

“…Dietary inclusion of 50, 60, or 100% BSFL meal did not adversely impact Atlantic salmon pre-smolt that had no significant gene expression ( il4 , tgf1 , il10 , ifn , il8 , and myd88 ) when compared to the control ( Li et al, 2019 ) and seawater phase ( il1b , il17a , myd88 , il8 , il4 , mhcl , il10 , ifn , tgf , cd8 , and foxp3 ) with no significant expression of cytokines ( Li et al, 2020 ). Immune gene expression was activated in the intestines of both larval and juvenile zebrafish ( IL1b , IL10 , IL6 , and tnfa ) ( Zarantoniello et al, 2018 ; Zarantoniello et al, 2019 ; Zarantoniello et al, 2020a ; Zarantoniello et al, 2020b ; Zarantoniello et al, 2021 ; Zarantoniello et al, 2022 ), juvenile rainbow trout ( IL10 , tnf , and tlr5 ) ( Cardinaletti et al, 2019 ), both the proximal and distal intestines of Atlantic salmon ( cd3 and foxp3 ) ( Li et al, 2019 ), and in the distal intestine of rainbow trout ( il1b and tlr1 ) ( Mohan et al, 2022 ; Ratti et al, 2023 ), which supports our research findings in the channel catfish. As an alternative to fish meals, BSFL-supplemented meals had no detrimental effects on growth and dramatically increased the cytokine expression in the gut of seabass ( Hender et al, 2021 ).…”

The Application of Synthetic Flavors in Zebrafish (Danio rerio) Rearing with Emphasis on Attractive Ones: Effects on Fish Development, Welfare, and Appetite

“…Starting from a commercial diet for zebrafish (Zebrafeed; Sparos LDA, Olhão, Portugal), used as control (CTRL diet) (for composition, please see [48]), four experimental diets were prepared as follows: (i) PG diet obtained by adding 1% (w/w) of Propylene Glycol (the basic solvent of the flavors; PG) to the control diet; (ii) A1 + diet obtained by adding 1% (w/w) of F25 as attractive/positive flavor to the control diet; (iii) A2 + diet obtained by adding 1% (w/w) of F35 as attractive/positive flavor to the control diet; (iv) A − diet obtained by adding 1% (w/w) of F32 as repulsive/negative flavor to the control diet. Flavors and PG were added daily to the right amount of the control diet at 1% (w/w) using a micropipette and vigorously mixed to guarantee a homogenous distribution in the feed.…”

“…Starting from day 5 dpf to the end of the trial (60 dpf), zebrafish were fed the experimental diets, tanks were cleaned and dead specimens collected and counted, according to Rashidian et al [52] and Zarantoniello et al [48].…”

New Eco-Sustainable Feed in Aquaculture: Influence of Insect-Based Diets on the Content of Potentially Toxic Elements in the Experimental Model Zebrafish (Danio rerio)

“…Hi can bioaccumulate potentially toxic elements from the rearing substrate [ 15 , 16 , 17 ], but their content is generally lower than the legal limit for feed [ 45 ]. Therefore, Hi prepupae have been proposed as a substitute for FM in fish feed [ 54 , 55 , 56 , 57 , 58 , 59 ].…”