Black soldier fly (Hermetia illucens) pre-pupae larvae meal in diets for European seabass (Dicentrarchus labrax) juveniles: Effects on liver oxidative status and fillet quality traits during shelf-life

A study was undertaken to evaluate the effect of dietary fishmeal (FM) replacement with Hermetia illucens prepupae larvae meal (HM) on oxidative stress indicators and fillet quality traits during shelf-life of European seabass (Dicentrarchus labrax) juveniles. HM was used replace 0%, 15%, 30% and 45% of dietary FM, corresponding to an inclusion level of 0%, 6.5%, 13%, and 19.5% of HM. After a feeding period of 62 days, fillet quality traits were analysed immediately after sampling (TO) and after three days of storage at +2/4 degrees C (T3). At the end of the feeding trial, hepatic lipid peroxidation and activities of superoxide dismutase decreased, catalase activity decreased at intermediary HM inclusion levels, while glutathione peroxidase and glutathione reductase activities were unaffected with the dietary inclusion of HM. Irrespectively of the diet, storage time did not affect the skin and fillet (dorsal and ventral regions) colour, while fillet pH was higher at the highest dietary HM inclusion level. Biometry traits, slaughter yield, fillet proximate composition, and liver fatty acid (FA) profile were not affected by dietary treatment. Fillet fatty acid profile was also unaffected by diet or storage time, except total C18-FA that decreased at the two intermediary levels of HM inclusion, n-6 PUFA that was higher in fillets from fish fed the HM-based diets, and total n-3 PUFA that decreased with the increase of dietary HM level at T3. The n3/n-6 ratio was not affected by the diets but decreased with the refrigeration time. Docosapentaenoic acid (DPA; 22:5n-3) decreased with the storage time, irrespectively of the dietary treatment. Fillet lipid peroxidation increased with storage time but decreased with the dietary inclusion of HM. Overall, dietary replacement of fish meal by HM up to 19.5% (22.5% of total dietary protein) did not affect the fillet quality traits and shelf-life of European seabass while reducing fillet lipid oxidation.