Potential of shrimp waste meal and insect exuviae as sustainable sources of chitin for fish feeds

Aquaculture is one of the world's fastest growing food-producing sectors, providing more than half all fish consumed globally for human nutrition. However, to maintain such growth and meet increasing demand aquatic food, sustainable raw materials feeds are needed. In this regard, insects represent most promising alternatives meal (FM) protein source use in aquafeeds. addition protein, contain bioactive compounds, as chitin, which a natural polysaccharide abundantly present pupal exuviae some insects. Studies have shown that dietary chitin or its derivate chitosan acts prebiotic thus modulating gut microbial communities fish. Accordingly, study aimed evaluate effect two waste products rich i.e., shrimp head (SHM), insect (Hermetia illucens) on microbiota rainbow trout (Oncorhynchus mykiss). Three isoproteic, isolipidic, isoenergetic diets containing either FM, SHD, combination FM 1.6% (PEM) were tested through 91-day feeding trial. At end experiment, no differences final mean body weight, specific rate, feed conversion ratio values observed between experimental groups. Mortality was <1% it did not correlate with diet entire duration modulatory detected. Indeed, bacterial species richness improved by including exuviae. particular, Firmicutes Actinobacteria phyla, mainly represented Bacillus, Facklamia, Brevibacterium, Corynebacterium genera, enriched receiving These genera chitinolytic short-chain fatty acids (SCFAs)-producing bacteria. SCFAs production confirmed gas chromatography analysis, detected highest amount butyrate feces fed meal. Functional inference analysis intestinal using PICRUST metagenome prediction tool, showed response diet. eleven pathways significantly different control PEM diet, whereas twenty functional traits SHM Overall, our data from insect's represents ingredient, better SHM, positively trout.