Dietary flavonoids from Allium mongolicum Regel promotes growth, improves immune, antioxidant status, immune-related signaling molecules and disease resistance in juvenile northern snakehead fish (Channa argus)

The present study was conducted to evaluate the effects of dietary flavonoids from Allium mongolicum Regel (AMRF) supplementation on growth, antioxidant and immune status, immune-related genes expression and disease resistance in Channa argus. A basal diet was supplemented with AMRF at 0, 10, 20 or 40 mg/kg feed for 56 days. The result revealed that weight gain (WG) and specific growth rate (SGR) were significantly increased (P < .05) with the increase of dietary AMRF levels from 0 to 40 mg/kg. All AMRF-supplemented groups (10, 20 or 40 mg/kg) significantly enhanced (P < .05) serum AKP, lysozyme activity, C3, IgM concentration, liver antioxidant enzymes activity (SOD, CAT and GSH-Px) or decreased (P < .05) serum cortisol, liver MDA content, serum ALT and AST activity. Meanwhile, AMRF administration significantly up-regulated (P < .05) the expression of SOD, IgM, HSP70, HSP90, I kappa B-alpha and GR or down-regulated (P < .05) NF-kappa B p65 and inflammatory cytokines (TNF-alpha, IL-1 beta and IL-8) transcription in head kidney of C. argus. After challenge with Aeromonas hydrophila, survival rates in all AMRF treatment groups were significantly increased (P < .05). These results indicated that dietary intake containing AMRF enhanced growth, antioxidant and immune response and regulated immune-related genes expression and increased disease resistance against Aeromonas hydrophila in snakehead fish, with greatest effects in fish given 40 mg/kg AMRF for 56 days.