Bệnh mù mắt do liên cầu khuẩn gây ra ở cá bớp nuôi tại Khánh Hòa

Abstract

     Streptococcosis is one of the most serious diseases in a variety of fish species. This study describes the streptococcus isolated from blind cobia culture in Khanh Hoa province. All isolated strains were identified as S. iniae by morphological and biochemical tests. The 16S rRNA sequences of the 4 S. iniae isolates showed 100% similarities to reference sequences from Genbank (NCBI) based on the 493-500 bp. The virulence of the isolates is high. Experimental challenge of cobia via intraperitoneal injection resulted the LD50 ranging from 10^3.6 – 10^4.6 CFU/fish within a seven days period. Twelve days after challenge, S. iniae can not be isolated from any organism of surviving cobia.

Keywords: Cobia, streptococcus, virulence, LD50