Effect of oligochitosan and oligo‐β‐glucan supplementation on growth, innate immunity, and disease resistance of striped catfish (Pangasianodon hypophthalmus)

Oligochitosan (COS) and oligo‐β‐glucan (βOG) were prepared by gamma Co‐60 irradiation of chitosan/H2O2 and β‐glucan/H2O2 solutions. The striped catfish (Pangasianodon hypophthalmus) was fed diets containing 0–200 mg COS, βOG, and a mixture of COS/βOG per kg feed for 45 days, and then challenged with Edwardsiella ictaluri bacterium. The effects of supplemented COS, βOG, and a mixture of COS/βOG on immune stimulation and growth performance in striped catfish were investigated. The results indicated that when striped catfish fed with 100–200 mg COS or βOG/kg feed the growth performance was significantly improved and the mortality was considerably decreased. Furthermore, striped catfish fed with supplementation of 50 mg COS + 50 mg βOG/kg feed was the best for increasing weight gain (∼26%) and for decreasing mortality (∼38%) compared with the control group. Moreover, phagocytic activity and lysozyme activity of fish were enhanced by feeding diet‐supplemented COS and/or βOG. Thus, COS and/or βOG can be potentially utilized as the immunostimulants and growth promoters for aquaculture.