1. Drugs in Aquaculture Dr. Craig Kasper

2. Drugs/chemicals used in aquaculture Feed additives (Sulfonamides) –Sulfamerazine (fish grade) and Romet-30 Effective for bacterial infections 220 mg/kg fish for 14 days. Some treatments recommend 3 days, fewer side-effects. –Toxicity may occur - Kidney damage (drug crystal formation in renal tubules) Clinical signs – bloating/dropsy (stomach full of water) Trout very suceptable. Commercial availability in feed has limited many problems

3. Drugs/chemicals used in aquaculture Sulfonamides (continued) –Sulfamerazine (fish grade) No longer available –Romet-30 Suggested dose (furunculosis) – 50mg/kg fish/day for 5 to 7 days Also effective for ESC Still used in the catfish industry.

4. Drugs/chemicals used in aquaculture Terramycin (oxytetracycline) – TM50 –Generally drug of choice in aquaculture –Recommended dose – 55-83mg/Kg fish/day for 10 days –Effective against gram neg. bacteria (BKD?) ERM, Furunculosis, CWD, etc. – Requires withdrawal period of at least 21 days. –Should not be fed on prophylactic basis! Resistance to oxytetracycline can occur in most bacterial fish pathogens (Meyer and Schnick 1989)

5. Drugs/chemicals used in aquaculture Therapeutants added to water –Methods Static bath – most reliable for raceways/tanks/troughs Constant flow – safe and can be used in most situations when fish reared in running water Prolonged – lower doseage, but constant emersion. –Chemicals Formalin –Most widely used agent in fish culture –(solution contains 37% formaldehyde in water)

6. Drugs/chemicals used in aquaculture Chemicals (cont.) –Quaternary Ammonium compounds Benzalkonium chloride/Hyamine Antibacterial, toxic!!! 48 hr LD50 at 1.12 g (catfish) Now only limited use in food fish –Potassium Permanganate Strong oxidizing agent Great for fungus!!

7. Drugs/chemicals used in aquaculture Chemicals (cont.) –Copper Sulfate (<6.4 mg copper/L water) –Also called Cutrine Algaecide/bactericide/parasiticide Effective on scaled fish, but can cause problems with scaleless fish (catfish). Can produce kidney necrosis, destruction of hematopoietic tissue, increased liver fat and inhibition of digestive enzymes. –NaCl (salt) (uniodized!!) Most overlooked treatment Can be very effective Was classified as a drug until recently. 3% recommended if possible (10-30 min)

13. Always the legal stuff....

18. What else is good? Some options are not “drugs,” per se, but natural products that haven’t been applied to fish (at least not in any scientific method.) Many products in traditional medicine/herbs, etc. can and are used for fish health!

19. GRAS (generally regarded as safe) Spices/flavorings: basil, garlic, salt, fennel Essential oils: from the above spices/plants. Natural solvent-free extracts: peach kernal (persic oil) Many others haven’t even been considered