Fishmeal Replacement by Full-Fat and Defatted Hermetia illucens Prepupae Meal in the Diet of Gilthead Seabream (Sparus aurata)

Insect proteins are considered as suitable low environmental impact alternatives to fishmeal for sustainable aquafeeds. Among the different insect species, Hermetia illucens has attracted research and industrial interest due to its ability to grow well on organic side streams, its high protein content and favorable amino acid profiles. Its lipid content although high is characterized by a lack of EPA and DHA that are essential to fish nutrition and thus a defatted form of Hermetia meal might be of better use in fish diets. Hence, two feeding trials were conducted to investigate the effects of the partial fishmeal replacement by increasing levels of a full-fat (up to 276 g/kg) and a defatted (up to 174 g/kg) H. illucens meal on feed intake, growth, feed utilization and nutrient compositions of gilthead seabream (Sparus aurata). Results showed that both the fat content and the inclusion level of H. illucens meal are critical for the success of fishmeal replacement in the diets of S. aurata as they strongly affect feed consumption. A lower palatability of H. illucens meal was observed when included at high dietary levels with the defatted form being more readily accepted by fish. The defatted H. illucens meal is more suitable than the full-fat type to replace fishmeal, with a dietary level of about 81-104 g/kg supporting the highest feed consumption, the highest growth, an unaffected proximate composition and a better feed utilization by S. aurata.

Automated summary

Insect proteins, particularly Hermetia illucens meal, have been identified as potential substitutes for fishmeal in aquafeeds. The lipid content and inclusion level of H. illucens meal have significant effects on feed consumption and palatability for fish. The defatted form of H. illucens meal is more suitable than the full-fat type for fishmeal replacement, with an optimal dietary level of approximately 81-104 g/kg for the highest feed intake, growth, unchanged proximate composition, and improved feed utilization by gilthead seabream.