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/H O and β-glucan/H O 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.