Effect of Serum and Mucus of Blue Tilapia, Oreochromis aureus on Infectivity of the Parasitic Dinoflagellate, Amyloodinium ocellatum in Cell Culture

Abstract

We studied the ability of Amyloodinium ocellatum to infect gill cell cultures in the presence of serum or mucus from naive blue tilapia Oreochromis aureus. Serum concentrations as low as 1.25 % markedly inhibited parasite infectivity. Serum concentrations greater than 10 % were completely inhibitory. Mucus had considerably less inhibitory activity than serum. Heating serum to 47°C for 20 min or 56°C for 30 min, as well as treating serum with zymosan or carrageenan, suggested that a complement-like factor was responsible for at least some of the activity, but that other factors may also influence parasite infectivity.