Submitted to: Fish Nutrition and Feeding Symposium Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: April 12, 2004
Publication Date: May 2, 2004
Citation: Whittington, R., Lim, C.E., Klesius, P.H. 2004. Effect of ß-d-glucan on the growth response and efficacy of streptococcus iniae vaccine in nile tilapia, oreochromis niloticus. 11th International Symposium on Nutrition and Feeding in fish, Phuket Island, Thailand. Technical Abstract: ß-D-glucans are one of the most frequently used immunostimulants in aquaculture. Thus this study was conducted to determine the effect of feeding ß-D-glucans pre- and post vaccination on the growth response and resistance of Nile tilapia to Streptococcus iniae. Vaccinated and non-vaccinated fish were fed 0, 50, 100 or 200 mg ß-D-glucan/kg diet to satiation twice daily for 10 weeks. Following S. iniae challenge, relative percent survivals (RPS) were 97, 100, 100, and 93 percent for vaccinated fish fed 0, 50, 100, and 200 mg ß-D-glucan/kg feed, respectively. However, RPS for non-vaccinates fed 50, 100, and 200 mg ß-D-glucan/kg diet were 28, 54 and 38 percent, respectively. The feed efficiency ratio and mean weight gain were not significantly affected. ß-D-glucans did not enhance vaccine efficacy. However, ß-D-glucans at 100 mg/kg diet did significantly increase non-specific immune responses of fish to S. iniae. Although the glucans at 100 mg/kg diet did enhanced non-specific immune defenses against S. iniae, this stimulation did not improve specific immune defenses provided by vaccination.