Dietary Supplementation with Prebiotic Chitooligosaccharides Enhances the Growth Performance, Innate Immunity and Disease Resistance of Nile Tilapia (Oreochromis niloticus)

Abstract

Prebiotics acting as immunosaccharides exhibit immunomodulatory functions to improve the immune defense of the host against infectious diseases. The purpose of the present study was to investigate the effects of dietary chitooligosaccharide (COS) supplementation on the growth, innate immunity and disease resistance of Nile tilapia (Oreochromis niloticus) fed a diet containing 0.4%, 0.8% and 1.2% COSs for 8 weeks. The results showed significant increases in weight gain (WG), feed efficiency (FE) and specific growth rate (SGR) in COS-supplemented fish compared to fish in the control group. The fish exhibited a significant decrease in cumulative mortality in fish fed 0.8% and 1.2% COS when challenged with Streptococcus iniae. The immune parameters, including phagocytotic activity (PA), respiratory burst (RB) activity, and superoxide dismutase (SOD) activities of the head kidney and serum lysozyme, as well as the expression of TNF-α, IL-1β and IL-8, were revealed in 0.8% and 1.2% COS-supplemented fish. These results demonstrated that COS could be used as a prebiotic and that dietary supplementation with 0.8% COS could improve growth performance and innate immunity against pathogen infections in Nile tilapia.