25/03/2026

In this study, Hermetia illucens meal was used as an ingredient in the diet of flathead grey mullet (Mugil cephalus) for the first time. This fish species is receiving increasing global attention due to its favourable biological characteristics, including low trophic feeding habits and high adaptability to diverse environmental conditions. In addition, its relatively low dietary protein requirement makes it a promising candidate for aquaculture diversification in the Mediterranean region, where carnivorous species still dominate production. Our results identified an inclusion threshold for H. illucens meal in the M. cephalus diet. Above this threshold, gut and spleen histology were negatively affected, likely due to the high chitin content of the ingredient. In contrast, low inclusion levels did not impair growth and promoted stimulation of the intestinal innate immune response. We conclude that H. illucens meal represents a suitable dietary ingredient for flathead grey mullet when included at low levels.

Defatted Black Soldier Fly Meal as a Dietary Protein Source for Grey Mullet (Mugil cephalus): Effects on Growth Performance, Gut Morphology, Spleen and Liver Health