Black Soldier Fly (Hermetia illucens) Larvae and Prepupae Defatted Meals in Diets for Zebrafish (Danio rerio)

Abstract

The black soldier fly (BSF) Hermetia illucens is receiving increasing attention as a sustainable fishmeal alternative protein source for aquaculture. To date, no studies have explored the effects of fishmeal replacement with BSF V instar larvae or prepupae meals due to their peculiar nutritional properties on fish performances. This study investigated the effects of 100% replacement of fishmeal (control diet) with defatted BSF meals (V instar larvae and prepupae meals, treatments) on growth performance and welfare of zebrafish (Danio rerio), from larvae to adults, in a 60-day feeding trial. Following the inclusion of BSF meals, the expression of key genes involved in growth (igf1, igf2, mstnb, myod1, myog, myf5), hydrolysis of chitin (chia.2, chia.3, chia.5), immune- (il1b, il6, tnfα), and stress- (hsp70 and nr3c1) responses, as assessed by qPCR, was modulated in all of the molecular pathways, except for the stress response. Overall, our findings showed that both BSF meals can totally replace fishmeal without adverse impacts on adult zebrafish growth parameters (final total and standard length, final body weight, weight gain, daily growth rate, specific growth rate) and welfare, with BSF prepupae meal inducing the most beneficial effects, thus suggesting their potential application to meet fish requirements in aquaculture.

Replacing Dietary Fish Meal with Defatted Black Soldier Fly (Hermetia illucens) Larvae Meal Affected Growth, Digestive Physiology and Muscle Quality of Tongue Sole (Cynoglossus semilaevis)

“…Therefore, 40% inclusion of DBLM can be used successfully in standard diets for P. fluviatilis ( Stejskal et al, 2020 ). The abovementioned similar findings were confirmed once again in Danio rerio , which also revealed the positive impacts of DBLM on fish at the molecular level ( Lanes et al, 2021 ). In general, the DBLM not only has high nutritive value but also represents good palatability, characteristics that can be better absorbed and utilized, and some beneficial effects on farmed fish.…”

The effect of laboratory diet and feeding on growth parameters in zebrafish

“…This revealed a significant effect of diet on zebrafish SGR (One-way ANOVA: F (3, 233) = 311.1, p < 0.0001) with the optimal diet identified as category 4, defatted prepupae meal (Fig. 7A) 37 .…”

“…7B). Further analysis with Tukey's multiple comparison test revealed an insect-based diet (defatted prepupae meal) to be optimal for percentage weight gain compared to all other feeding categories, closely followed by animal-based diet with 50% FM 37 . No significant difference was seen between the other feeding categories 25,27,29,36 .…”

Alternative Proteins for Fish Diets: Implications beyond Growth

“…When Atlantic salmon are fed diets with insect meal (black soldier fly larvae meal at 10% and 15% inclusion) for 56 days, LPS-challenged isolated leukocytes showed a lower expression of the stress-related markers heat shock proteins (HSP70 and HSP27) [142]. When zebrafish were fed defatted black soldier fly V instar or prepupae meal (50% inclusion totally replacing fishmeal) for 60 days (from larvae to adults), an increase in the expression of HSP70 and nr3c1 (glucocorticoid receptor) was observed [198]. Interestingly, differential expressions were observed only in juvenile zebrafish, and HSP70 was only modulated by V instar black soldier fly meal, whereas nr3c1 was only modulated by prepupae meal.…”