National Academy of Agricultural Sciences (NAAS)
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PRINT ISSN : 2319-7692
Online ISSN : 2319-7706 Issues : 12 per year Publisher : Excellent Publishers Email : editorijcmas@gmail.com / submit@ijcmas.com Editor-in-chief: Dr.M.Prakash Index Copernicus ICV 2018: 95.39 NAAS RATING 2020: 5.38 |
Aeromonas hydrophila is a potent pathogen that causes mortalities in tilapia. The present study evaluated the effectiveness of oxytetracycline (OTC) oral and bath therapies on Nile tilapia Oreochromis niloticus against A. hydrophila infection. Medicated feed was prepared by admixing oxytetracycline dihydrate powder and fed to fish at 60 mg OTC kg/biomass/day for 10 days. Bath therapy was done by immersing the fries in OTC suspensions (20 mg/l) for 1 h for 4 days. Aeromonas hydrophila was moderately virulent, causing 20-55% mortalities at 2×106 - 2×107cfu/ml level by abrasion-bath treatment. The LD50 value for juvenile tilapia was 6×107cfu/fish. Efficacy of OTC was evaluated by abrading the tilapia followed by immersion in A. hydrophila suspension containing 2×107-5×107cfu/ml for an hour. After 3 days of disease progression, the fish were given OTC feed and/or bath treatment. The oral and bath therapies in fries with OTC recorded low mortalities (17 and 21%) than the respective control (37 and 24%). The juveniles appeared to be susceptible to A. hydrophila than the fries. It recorded 66.7% mortality in OTC fed group than in control (90%). The oral therapy was better than the bath therapy against A. hydrophila infection. Since OTC is one of the approved antibiotics for treating bacterial diseases of fish and effective in controlling A. hydrophila, judicious use of OTC feed is recommended for the control of Aeromonas infection in tilapia.
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