Tenebrio molitor larvae meal as alternative ingredient for farmed blackspot sea bream (Pagellus bogaraveo): effect on physical and chemical fillet traits.

Fish meal is the main protein source for carnivorous freshwater and marine fish. However, the increase of fish meal request has dramatically caused the reduction of natural stocks, and environmental impact. Recently, insects have been identified as one alternative sustainable protein source for feeding fish and its utilization seems to have numerous advantages. Nevertheless, more information are necessary for better understanding its possible role on fish quality. The aim of this study was to evaluate the partial replacement of fishmeal (FM) with Tenebrio molitor larvae meal (TM) on final quality muscle of farmed blackspot seabream (Pagellus bogaraveo), a promising finfish species for aquaculture. Three experimental isoenergetic diets were formulated: TM0, contained only FM as main protein source, TM28 and TM50 at 28 and 50% of Tenebrio molitor larvae replacing FM, respectively. Diets were fed to three replicate tanks of fish per treatment (14 fish/tank) for 131 days. After the trial, eight fish per diet treatment were randomly sampled for determination of physical and chemical meat characterization. In this study, the performed physical analyses on fish flesh were colour of skin and fillets, pH, texture and Water Holding Capacity. Regarding chemical features, proximate composition (moisture, crude protein, ether extract and ash) and fatty acids profile of fish were also analysed. Different diets did not affect the colour of skin. However, significant variations were observed in colour of fish fillets with a higher yellowness (b*) when insect meal was added in the diets (2.51 and 2.67 vs 0.69 in TM25, TM50 and TM0, respectively); instead Hue* was resulted higher with only FM in diet (165.89 vs 134.45 and 132.91 in TM0, TM25 and TM50, respectively). No significant differences were detected for Water Holding Capacity, hardness, cohesiveness, resilience, gumminess and adhesiveness. pH was found lower in TM50 (5.97) than TM0 and TM28 (6.12 and 6.15) specimens. Proximate composition of fillets was not affected by the diets. Fatty acid composition of samples was also determined. No detrimental effects on fillet quality have been reported. Therefore, the use of Tenebrio molitor larvae as alternative protein source in feeding of blackspot seabream seems to be encouraging