Effect of dietary β-glucan on survival and resistance to Cryptocaryon irritans infection of Chaetodon auriga

Abstract

Chaetodon auriga is not only the most common fish in Nha Trang bay, but also the most popular fish in aquarium now. This species is very sensitive with pathogens, especially the marine white spot disease caused by Cryptocaryon irritans. Aim of this study is to evaluate the effectiveness of β-glucan supplemented diet on survival and resistant ability of the fish to C. irritans infection. The fishes were fed by 0% and 2% β-glucan supplemented diets for duration of 30 days, then infected with C. irritans through the C. irritans - infected fish and the fishes were then evaluated on survival and hematology parameters. Results showed that the survival of fishes fed on βglucan supplemented diet (52.38%) was higher than that of the fishes fed on the diet without β-glucan supplementation (14.29%) (p<0.05). The number of erythrocyte, leukocyte, percentage of leukocyte types, thrombocytes of the fishes fed on 2% β-glucan supplemented diet was higher than that of the fishes fed on 0% β-glucan supplemented diet. The study results show that the diet with β-glucan supplementation at 2% increases natural immunity of C. auriga to C. irritans infection.