The effect of defatted black soldier fly meal (Hermetia illucens) inclusion in the formulated diet on the growth, gene expression, and histopathology of juvenile lobster (Panulirus ornatus Fabricius, 1798)

The present study investigated the potential use of defatted black soldier fly (Hermetia illucens) meal as a protein source in the formulated feed for juvenile lobsters, Panulirus ornatus. A total of 160 heads of juvenile lobsters with initial weight of 0.24 ± 0.01 g and initial length of 21.77 ± 0.32 mm were distributed evenly into 16 rectangular fiberglass aquaria and kept individually for 8 weeks of the feeding experiment. Four formulated feeds containing defatted BSF meal as fishmeal replacements at 0%, 25%, 35%, and 50% and total dietary protein to energy ratio of ~ 26 g CP MJ−1 were prepared and assigned as BSF0, BSF25, BSF35, and BSF50, respectively. Fishmeal is technically a suitable aquafeed ingredient in terms of crude protein, moisture, and amino acid compositions. The partially substituted defatted BSF meal has higher crude lipid and ash content than fishmeal. At the end of week 8 of feeding trial, the specific growth rate, length increment, survival rate, and moulting rate of juvenile lobster were not significantly (P > 0.05) affected by the fishmeal replacement. The fishmeal replacement with the defatted BSF meal did not significantly (P > 0.05) alter the whole-body proximate composition of the juvenile lobster. However, it significantly (P < 0.05) affected the superoxidase dismutase of juvenile lobsters. The cytokine cell expression analysis indicated that up to 35% of fishmeal replacement increased the inflammatory cytokine cells (Interleukin 8 and 17) of juvenile lobster, while an adverse impact was observed on juvenile lobster receiving 50% of fishmeal replacement by BSF meal. Histopathological analysis showed that the hepatopancreas cells of juvenile lobsters were damaged following fishmeal replacement beyond 35%. The present study indicated that up to 35% of defatted BSF meal can be used as fishmeal replacement in the formulated feed of juvenile lobster.