Black Soldier Fly, <em>Hermetia illucens</em> as an Alternative to Fishmeal Protein and Fish Oil: Impact on Growth, Immune Response, Mucosal Barrier Status, and Flesh Quality of Juvenile Barramundi, <em>Lates calcarifer</em> (Bloch, 1790)

• Main Authors: Amanda Hender, Muhammad A.B. Siddik, Janet Howieson, Ravi Fotedar
• Format: Article
• Language: English
• Published: MDPI AG 2021-06-01
• Series: Biology
• Subjects: Insect larvae; fishmeal replacement; intestinal morphology; acidic mucin; fatty acid; cytokine expression
• Online Access: https://www.mdpi.com/2079-7737/10/6/505

A feeding trial was conducted to test the effects of partial replacement of fishmeal (FM) protein and fish oil (FO) with partially defatted black soldier fly, <i>Hermetia illucens</i> insect protein, and oil, respectively, on growth performance, immune response, gut and skin barrier status, and flesh quality in juvenile barramundi. Four isonitrogenous and isocaloric diets used in the study were a control diet based on FM, 30% FM replaced with <i>H. illucens</i> protein (HiP), 30% FO replaced with <i>H. illucens</i> oil (HiO), and both 30% FM and 30% FO replaced with <i>H. illucens</i> protein and oil (HiPO). Diets were fed twice a day to satiety in triplicated groups of barramundi with an initial body weight of 1.74 ± 0.15 g per fish. At the end of the trial, growth and feed utilization indices were found insignificant (<i>p</i> > 0.05) between the test diets and control. A significant increase in bactericidal activity was observed in fish fed the HiP diet while serum lysozyme activity was unchanged. Stress-related heat shock proteins (HSP70 and HSP90) did not differ significantly among the test diets while immune-relevant genes (IL-1β and IL-10) were significantly upregulated in HiP and HiOP groups. The number of mucin cells were increased in the gut and skin of HiP and HiOP fed fish when compared to the control diet. The total fatty acid compositions (∑SFA, ∑MUFA, ∑PUFA, ∑n-3, and ∑n-6) in the muscles of barramundi were not significantly influenced with <i>H. illucens</i> protein and oil diets when compared to the control.