Effects of Graded Dietary Inclusion Level of Full-Fat Hermetia illucens Prepupae Meal in Practical Diets for Rainbow Trout (Oncorhynchus mykiss)

This study investigated the effects of dietary inclusion levels of full-fat Hermetia illucens prepupae meal (H) on growth and gastrointestinal integrity in rainbow trout (Oncorhynchus mykiss). A 98-day study was conducted using triplicate groups of trout (initial body weight, 137 \ub1 10.5 g) kept in 1-m3 tanks in a flow-through well water system. Three dietary treatments were prepared: one based on fishmeal and purified protein-rich vegetable ingredients (H0), and two experimental diets including graded levels of H meal (25% and 50%, referred to as H25 and H50, respectively). At the end of the feeding trial, no differences were observed in growth performance and plasma metabolite levels, with the biometric data confirmed by the liver expression of the genes involved in somatic growth regulation (igf1 and mstn1a). In the H50 group, a three-fold up regulation of liver hsp70 was observed. An activation of the stress/immune response (il-10, tnf-\u3b1, and tlr-5) was observed in medium intestine in the H25 and H50 groups (p < 0.05) together with a villi length reduction detected through histological analyses. Liver histology and Fourier Transform Infrared Imaging (FTIRI) spectroscopy highlighted an increase in lipid deposition. These findings suggest that caution should be taken into account when 50% replacement of conventional ingredients with H is selected

Reducing the Use of Antibiotics in European Aquaculture with Vaccines, Functional Feed Additives and Optimization of the Gut Microbiota

This review presents several alternatives to replace antibiotic therapy and make the European aquaculture industry more friendly and environmentally sustainable. The first part of this review highlights the growing importance of the aquaculture industry worldwide for its ability to supply low-cost proteins and lipids. The second part discusses different strategies for these replacements, from recombinant vaccines to diets with low environmental impact and rich in bioactive molecules that can benefit other species. Specifically, the beneficial effects of bioactive compounds present within insect meals are discussed. In addition, particular focus is placed on the importance of adopting sustainable protocols for fish farming, including supplements such as probiotics, prebiotics, and synbiotics capable of modulating the gut microbiota as the second brain. Those feed additives can stimulate European farmed species’ immunological systems, growth, and welfare

Black Soldier Fly (Hermetia illucens) reared on roasted coffee by-product and Schizochytrium sp. as a sustainable terrestrial ingredient for aquafeeds production

none16noPromoting circularity in the aquaculture sector through the conversion of great amount of organic by-products produced on land is a valuable strategy for a further development of the aquaculture sector. In this regard, insects represent a very promising example of bio-converting organisms; their application in aquafeeds, however, still faces possible limitations because of their lack in polyunsaturated fatty acids and the presence of chitin. The aim of the present study was to apply circularity to Black Soldier Fly (BSF) (Hermetia illucens) culture and to improve the insect's biomass fatty acid composition by culturing them on a land-produced by-product (coffee silverskin) enriched with a 10% Schizochytrium sp. The insect biomass was then used to formulate five fish diets containing 0, 25, 50, 75 and 100% of insect meal respect to fish meal, respectively. Diets were used for a feeding trial during zebrafish (Danio rerio) larval development (21 days) and a multidisciplinary approach including biometry, histology, gas chromatography, spectroscopy (FTIR), microbiota analyses and molecular biology was applied to better understand fish responses to the new diets. Results showed that the 50% substitution of fish meal with insect meal represented the best compromise between ingredient sustainability and proper fish growth and welfare. Fish fed with higher BSF inclusions (75 and 100%) showed a severe degree of hepatic steatosis, microbiota modification, a higher lipid content (FTIR), fatty acid modification and higher expression of both stress and immune response markers.mixedZarantoniello, Matteo; Zimbelli, Andrea; Randazzo, Basilio; Compagni, Martina Delli; Truzzi, Cristina; Antonucci, Matteo; Riolo, Paola; Loreto, Nino; Osimani, Andrea; Milanović, Vesna; Giorgini, Elisabetta; Cardinaletti, Gloriana; Tulli, Francesca; Cipriani, Renato; Gioacchini, Giorgia; Olivotto, IkeZarantoniello, Matteo; Zimbelli, Andrea; Randazzo, Basilio; Compagni, Martina Delli; Truzzi, Cristina; Antonucci, Matteo; Riolo, Paola; Loreto, Nino; Osimani, Andrea; Milanović, Vesna; Giorgini, Elisabetta; Cardinaletti, Gloriana; Tulli, Francesca; Cipriani, Renato; Gioacchini, Giorgia; Olivotto, Ik