Effects of Arnebia benthamii Extract on Growth Performance, Immunological Parameters and Disease Resistance against Flexibacter columnare in Spotted Snakehead Channa punctata (Bloch)

Herbal immunostimulants are known to improve disease resistance in fish by enhancing specific and non-specific defensive mechanisms. The present study was conducted to evaluate the effects of Arnebia benthamii extract (AE) on growth rate, immune status, and disease resistance towards Flexibacter columnare in spotted snakehead Channa punctata. Each experimental group of healthy C. punctata was fed on one of the four experimental diets viz. basal diet (without any AE supplementation), AE10 (supplemented with 10 mg AE/kg basal diet), AE20 (supplemented with 20 mg AE/kg basal diet) and AE40 (supplemented with 40 mg AE/kg basal diet) for 42 days. When the concentration of Arnebia benthamii was raised from 0 to 40 mg/kg, the weight gain (WG) and specific growth rate (SGR) were considerably enhanced. The lysozyme activity, C3, C4, and serum globulin levels were also significantly increased in all Arnebia benthamii supplemented groups. IgM concentration in fish fed on AE40 diet was significantly higher than in fish fed on basal diet. All A. benthamii treatment groups exhibited significantly higher survival rates after being challenged with F. columnare. These findings showed that supplementing diet of C. punctata with A. benthamii improved growth, immunological response, and disease resistance against F. columnare, with the greatest benefits in fish fed on AE40 diet for 42 days.