Abstract

Common carp (Cyprinus carpio) fry were fed diets containing defatted Hermetia illucens (HI) larvae meal at three inclusion levels to investigate its effects on the nutriphysiological status, focusing on protein and fat digestibility (in vitro and in vivo), growth performance parameters, diet utilization, somatic indices, and GIT histomorphology. The HI meal was included at 0%, 2%, 4%, and 6%. A total of 240 carp fry were randomly divided into four groups, six replicates each (10 fish/tank), and the growth trials lasted 60 days. The dietary inclusion of HI meal up to 6% in carp feed did not significantly affect growth performance, feed utilization, or homeostasis. In vitro protein digestibility exceeded 97% across all treatments with pepsin, indicating efficient hydrolysis. However, the highest crude protein digestibility coefficients were recorded in all treatment groups, which differed significantly from the control group (90.5%). Also, villus width and crypt depth did not differ significantly; however, other parameters, such as villus height and area, showed some significant variations across the treatment groups. No adverse effects were observed on liver condition, structure, or function, reinforcing the safety of HI up to 6% in carp diets. In conclusion, this study demonstrates that HI can be incorporated as a functional, health-promoting ingredient in the diets of common carp fry.

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