Immunity stimulation of humpback grouper, Cromileptes altivelis juvenile against viral nervous necrosis (VNN) infection by immersion vaccination
2004
Roza, D. | Johnny, F. | Tridjoko((Balai Besar Riset Perikanan Budidaya Laut, Gondol (Indonesia)))
Vaccination may one of effective prevention method, practical and cheap. An experiment to evaluate the effectiveness of vaccine delivered by different dosages of vaccine and different duration of immersion periods was conducted at the Disease Laboratory of Research Institute for Mariculture, Gondol-Bali, Phase I; 360 fishes of humpback grouper juveniles (about 2-3 cm in total length) were bathed in VNN inactive vaccine for one hour at different dosages, namely 15 ml/l (A), 10 ml/l (B), 5 ml/l (C), and 0 ml/l (D) as a control. Phase II; fishes of humpback grouper juveniles were bathed in VNN inactive vaccine at different immersion periods, namely 1 hour (A), 2 hours (B), 3 hours (C), and 0 hour (D) as a control. Ten juveniles from each treatment were then subjected to challenge tests with VNN virus (LD50) phase I for 6 hours at 10 , 25 and 40 post vaccination and phase II at 10, 20 and 30 days post vaccination. The experiment was arranged in completely randomized design with four treatments and three replications. Clinical signs and survival of each groups were observed for two weeks. Phase I; result of challenge test showed that highest survival was gave by treatment as 15 ml/l (86.67 percent) 25 days post vaccination. Phase II; showed that treatment as 3 hours (86.67 percent) 20 days post vaccination. It was suggested that humpback grouper juveniles gave positive response to vaccination and 15 ml/l is optimum dosage of vaccine at least for 25 days, and the optimum immersion period to enhance immunity of humpback grouper juveniles against VNN is 3 hours.
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