Submitted to: Annual Meeting World Aquaculture Society
Publication Type: Abstract Only
Publication Acceptance Date: March 30, 2002
Publication Date: February 18, 2003
Citation: DARWISH, A.M., RAWLES, S.D., GRIFFIN, B.R. DOSE TITRATION OF OXYTETRACYCLINE AGAINST STREPTOCOCCUS INIAE INFECTION BLUE TILAPIA, TILAPIA AUREA.. ANNUAL MEETING WORLD AQUACULTURE SOCIETY. 2003. p.71. Technical Abstract: Experimental trails were performed to evaluate the efficacy of oxytetracycline (OTC) in controlling Streptococcus iniae infection in blue tilapia, Tilapia aurea. Minimum-inhibitory-concentration studies of OTC against several S. iniae isolates indicated general sensitivity at concentration of 0.25-0.5 ?g/mL. Oxytetracycline dose levels tested were 25, 50, 75 and 100 mg active ingredient per kilogram of fish body weight per day. Administration of medicated feed started within few hours after infection by waterborne exposure to S. iniae (after skin scraping) and continued for 14 consecutive days, followed by 21 d post-treatment observation. The 50 mg OTC treatment significantly increased the survival of the infected tilapia from 7 % in the infected non-medicated group to 45 %. The 75 and 100 mg OTC treatments had survival rates (85 and 98 %, respectively) significantly higher than the 50 mg treatment. There was no significant difference among both the 75 and 100 mg treatments and the uninfected non-medicated treatment (100 % survival). Survivors of the 100 mg OTC treatments were not carriers of the infection whereas 10 % of survivors receiving the 75 mg OTC level were carriers.