Defatted black soldier fly larvae meal as a dietary ingredient for tambaqui ( Colossoma macropomum ): Digestibility, growth performance, haematological parameters, and carcass composition

Black soldier fly (BSF, Hermetia illucens) meal is a prominent ingredient to keep up with the increasing demand of protein sources for aquafeeds. This study evaluated the digestibility of defatted BSF larvae meal (DBSFL) by indirect method, growth performance, haematological parameters, and carcass composition of tambaqui (Colossoma macropomum) fed diets containing DBSFL. The apparent digestibility coefficient of protein from DBSFL was 84.2%, corresponding to 42.9% of digestible protein. For the feeding trial, juvenile tambaqui (3.25 ± 0.01 g) were randomly distributed in 18 experimental units (100 L; n = 3; 27 fish/tank) in a recirculation system. Fish were fed to apparent satiation for 60 days with isoproteic and isocaloric diets containing 0%, 6%, 12%, 18%, 24% or 30% of DBSFL meal. At the end of feeding trial, fish length and weight were recorded; blood samples were drawn from caudal vein of three fish per tank, and three fish from each replicate were euthanized for analysis of carcass proximate composition. The inclusion of up to 30% DBSFL meal did not impair tambaqui growth performance and fish body composition. The blood cholesterol level of the fish fed diet with 30% DBSFL inclusion was higher, but within the limits recorded for that species. DBSFL meal seems to be an interesting and safe protein source for tambaqui farming. The use of this ingredient as protein source can encourage the circular economy by promoting environmental sustainability.