Astaxanthin enhances hematology, antioxidant and immunological parameters, immune-related gene expression, and disease resistance against in Channa argus

The present study was aimed to add 0, 50, or 100mg/kg of astaxanthin (AST) to the basal diet of Channa argus and determine the effects on hematology, antioxidant and immunological parameters, immune-related genes expression, and disease resistance. Adding 50 or 100mg/kg AST significantly enhanced (P<0.05) Hb content at 14, 21, and 28days and also the levels of Ht and RBC at 21 and 28days. Supplementing 50 or 100mg/kg of AST for 21 and 28days significantly increased (P<0.05) the level of serum antioxidant enzymes (SOD, CAT, and GSH-Px) or decreased (P<0.05) serum MDA content. The level of serum lysozyme significantly enhanced (P<0.05) at 28days and also IgM and C3 at 21days in 100mg/kg AST treatment and at 28days in 50 or 100mg/kg AST treatment. Meanwhile, 50 and 100mg/kg AST treatment significantly upregulated (P<0.05) the expression of HSP70, HSP90, IB-, and GR or downregulated NF-B p65 and inflammatory cytokines (TNF-, IL-1, and IL-8) transcription at 21 and 28days. Fish fed 50 and 100mg/kg AST enhanced (P<0.05) disease resistance against Aeromonas hydrophila (survival rate 51.0% and 58.0%, respectively). The present results suggested that AST enhanced hematology and serum antioxidant and immune response, regulated immune-related gene expression, and increased disease resistance against A. hydrophila in C. argus.