Fish Hatchery Management - fisheries & aquaculture

FISH HEALTH MANAGEMENT 281For the treatment of Aeromonas, Pseudomonag and Flexibacter sp- infectionsin catfish, the nitrofurans are fed at the rate of 4-5 grams active ingredientper 100 pounds of fish per day for 7-10 days. If the fish undertreatment are being fed at 3% of their body weight daily, it is necessary toincorporate 133-167 grams active ingredient per 100 pounds of food. Fishnever should be fed either of the nitrofurans for less than 7 days.Nitrofurans have been used as a prolonged-bath treatment for externalbacterial infections and as a prophalaxis during the transport of warmwaterfish. The levels recommended vary from 5 to 30 parts per million active ingredient.However, severe losses of channel catfish sac fry and swim-up fryhave occurred during treatment with 15 and 25 parts per million active nitrofurozone.Five parts per million should be adequate. It is suggested thatnitrofurazone not be used to treat channel catfish sac fry or swim-up fry. Ifit must be used, apply only the lowest concentration, with caution.Furanace (p-Ztgg, nitrofurpirinol) is a relatively new nitrofuran that hasbeen used to control bacterial infections of trout and salmon. It also appearseffective against bacterial infections in catfish, although it has beenused only on a limited basis for that species.Continued treatment of catfish is discouraged because furanace may causeinjury to the skin during prolonged exposures. In trout and salmon culture,furanace is used as a bath at I part per million active ingredient (0.038 gramper l0 gallons; 0.283 gram per 10 cubic feet) for 5-10 minutes, or at 0.1 partper million active ingredient (0.OOg8 gram active per 10 gallons; 0.0283gram active per l0 cubic feet) for an indefinite period. It is also fed at100-200 milligrams of active ingredient per 100 pounds of fish for 3-5 days.Thus, if fish are being fed 3% of their body weight daily, it is necessary tohave 3.3-6.7 grams of active ingredient per 100 pounds of food'SULFONAMIDESSulfonamides have been used since 1946 to treat bacterial infections of salmonids,but have been applied rarely to warmwater fish. They are registeredby the Food and Drug Administration.Presently, sulfamerazine and sulfamethazine are the sulfonamides mostwidely used. Generally, they are fed at a therapeutic level of 5-10 grams ofdrug per 100 pounds of fish per day for l0-21 days. Sulfonamides may betoxic to some fish species when the high dosages (10 gta-. per 100 poundsof fish per day ot mo.e) are fed. However, with the possible exception ofbacterial hemorrhagic septicemia caused by Aeromonas hydrophilia or Pseudomonasfluorescens, high drug levels seldom are required.ACRIFLAVINEAcriflavine is not registered by the Food and Drug Administration. A bacteriostat,it has been used widely for many years in the treatment of