Pengaruh Salinitas Air terhadap Tingkat Patogenitas Viral Nervous Necrosis pada Benih Kerapu Macan (Epinephelus Fuscoguttatus)

Abstract

A study of the effect of water salinity to pathogenicity of viral nervous necrosis in seed tigers grouper (Epinephelus fuscoguttatus) was conducted from January 2011 to April 2011 at the Laboratory of Molecular Biology of Fish Quarantine Center Class I Polonia, Medan and the Laboratory of Anatomy Pathology and Laboratory of Biochemical Investigation Center and Veterinary Testing Regional I Medan. The study aim was to determine the effect of salinity to the pathogenicity of viral nervous necrosis (VNN) in tiger grouper infected with VNN. Completely Randomized Design (CRD) was used in this study. The study consisted of five salinity treatments namely S20 (20 ppt), S25 (25 ppt), S30 (30 ppt), S35 (35 ppt) and S40 (40 ppt) and control K30 (30 ppt) without infection of VNN. Each treatment with three replication of 10 fish/20L sea/aquarium. Fish was injected with the virus intra muscular of 10-4/0,1ml (FID50). The data were analyzed using SPSS release 13. The results showed that salinity level affected pathogenicity of VNN, (p <5%). S30 showed high pathogenicity of VNN to the fish while S25 showed low pathogenicity. Some confirmation tests like hematology tests showed that erythrocytes number decreased while leukocytes number increased. Histopathology test showed that there were vacuolization around glial cells and the obstruction of blood vessels containing erythrocytes. RT-PCR test confirmed that S30 showed highest level of pathogenicity, while the S25 showed the lowest one. Of all the test confirmation showed the effect of salinity on the pathogenicity level of VNN in tiger grouper seed.