Oxidative Stress Response of Meagre to Dietary Black Soldier Fly Meal

Simple Summary Given the need of replacing fishmeal with more sustainable ingredients, insect meal has appeared as a suitable alternative. As a result, in recent years, a large number of studies have emerged regarding the use of insect meal in diets for several fish species. However, chitin, a component of insect meal, is frequently pointed as a potential bottleneck for the inclusion of high levels of insect meal in aquafeeds. On the other hand, dietary chitin was also highlighted as having positive effects on fish antioxidant status. In fact, insect meal antioxidant potential can also be related with the insect's nutritional composition, namely the lipid fraction. Nonetheless, few papers assessed the antioxidant effect of insect meal, particularly in marine fish species. The present study evaluated the effects of Hermetia illucens meal dietary inclusion on meagre liver and intestine oxidative status. The results show that with the tested Hermetia illucens meal levels, chitin or insect lipid composition does not greatly affect meagre liver or intestine oxidative status. Overall, it may be concluded that Hermetia illucens meal can be included as up to 30% of the diet without compromising meagre antioxidant status. This study aimed to assess the effect of Hermetia illucens meal (HM) dietary inclusion on meagre oxidative status. Thus, fish were fed a fishmeal-based diet (CTR diet) and three other diets with increasing levels of HM inclusion, namely 10%, 20%, and 30% (diets HM10, HM20, and HM30, respectively). At the end of the trial, hepatic and intestine superoxide dismutase, catalase, and glucose-6-phosphate dehydrogenase activities and malondialdehyde concentration were unaffected by the diet composition. Liver glutathione peroxidase activity was higher in the fish fed the HM20 diet than in the fish fed the CTR and HM30 diets, and glutathione reductase activity linearly increased with the dietary HM level. The hepatic total glutathione and reduced glutathione contents were significantly lower in fish fed the HM20 diet than in fish fed the CTR and HM10 diets. In the intestine, the oxidized glutathione (GSSG) content and oxidative stress index linearly increased with the increase in dietary HM level, with the GSSG content of fish fed the HM20 diet being significantly higher than of fish fed the CTR diet. In conclusion, 30% HM might be included in meagre diets without negatively affecting hepatic and intestine oxidative status.