MICROBIOLOGICAL STUDIES ON CHARACTERISTICS OF STREPTOCOCCUS INIAE ISOLATED FROM DISEASED TILAPIA NILOTICA AND AQUATIC ENVIRONMENTS | ||
| Veterinary Medical Journal (Giza) | ||
| Volume 50, Issue 2, April 2002, Pages 273-297 PDF (2.1 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/vmjg.2002.369252 | ||
| Author | ||
| L RADWAN* | ||
| Bacteriology, Mycology and Immunology Department | ||
| Abstract | ||
| Seventy-eight isolates of Streptococcus inte were recovered from 200 diseased brackish water Oreochromis niloticus (Nile tilapia) fish with an incidence of 86.7% of the total number of isolated Streptococcus species. To investigate the effect of nitrite, alkaline pH, salinity and water temperature on the susceptibility of Oreochromis niloticus (Nile tilapia) to streptococcosis; ten water sam- ples were collected and the results obtained were as follows: nitrite concentration was 3.2 ug/L wa- ter. pH was 8.2, salinity was 18 ppt (part per thou- sand) and water temperature was 26±2°C. environmentally stressed and experimentally infected fish showed mortality rate of 73.3% compared with a mortality rate of 46.6% in non- environmentally stressed fish. In the meantime, LD50 values for S. Iniae were 1 x 105.1 cfu/ml for environmentally stressed fish compared with Ix 105.5 cfu/ml for non-stressed tilapia. | ||
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