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United States Department of Agriculture

Agricultural Research Service

Research Project: EVALUATION OF COMPOUNDS AND STRATEGIES FOR CONTROLLING AQUATIC ANIMAL DISEASE

Location: Harry K. Dupree Stuttgart National Aquaculture Research Center

2008 Annual Report


1a.Objectives (from AD-416)
Develop data needed to demonstrate safety (animal, human, and environmental) and efficacy of compounds that are relevant to the needs of aquaculture. Determine the efficacy of compounds, biological control strategies, clearance rate and pathogenesis of parasites and fungi applicable to catfish, baitfish, and Morone sp. culture.

Conduct production efficiency trials with Channel x Blue catfish hybrids at multiple densities. Evaluate pond management using water circulators to improve production. Develop disease challenge models for catfish.


1b.Approach (from AD-416)
Submit the FDA-required Efficacy data for control of Ichthyophthiriasis by Potassium Permanganate. Submit the environmental assessment data for potassium permanganate and copper sulfate on channel catfish in earthen ponds. Submit the target animal safety data for potassium permanganate in channel catfish. Use in vivo challenge models and in vitro assays to investigate the efficacy of florofenicol against streptococcus infection in hybrid striped bass and tilapia. Evaluate the safety of florofenicol use in hybrid striped bass and tilapia. Evaluate praziquantel for control of asisan tapeworm in grass carp and golden shiners. Evaluate the biological control of trematode vectoring mollusks by determining comparative consumption and preference by snail-eating fishes. Determine the clearance rate of the catfish trematode (bobophorus) in channel catfish and the gil trematode in hybrid striped bass, golden shiners, and channel catfish. Determine the prevalence of trematodes in black and yellow crown night herons, little blue herons, snowy egrets, cattle egrets, and belted kingfishers. Determine efficacy of dimilin for the control of anchor parasites and fish lice in morone sp., golden shiners, and gold fish. Evaluate copper sulfate treatments to control snails under commercial farm conditions. Use the DNA sequence of F. columnare and F. psychrophilum or F. Branchiophilum to detect and "fingerprint" strains of pathogens by molecular techniques as restriction fragment length polymorphism (RELP) using polymerase chain reaction, or pulse field gel electrophoresis (PEGE).

Pond evaluations of channel/blue hybrids will be initiated. Simultaneously, channel/blue hybrids will be challenged by Flavobacterium columnare and Edwardsiella ictaluri to evaluate hybrid disease resistance. Coupled with the pond and disease challenge studies, engineering principles will be applied to develop improved methods for efficient, reduced-stress production, harvesting and transport of standard and hybrid catfish.


3.Progress Report
Conducted a field dose-confirmation study on the use of copper sulfate to control fungus on catfish eggs. Determined the margin of safety of copper sulfate to catfish eggs. Developed an applicable procedure to determine the rate copper sulfate dissolves, and determined this rate at different temperatures and in various water chemistries. Developed an effective treatment for a protozoan parasite (Costia) infesting sunshine bass in tanks. Evaluated hydrogen peroxide against a natural fungi infestation on channel catfish eggs under conditions of a typical catfish hatchery. Developed an effective coldwater net disinfectant treatment for red-rim melania, an aquatic snail that spreads parasites to cultured fishes and can become entrapped in fish nets and other equipment. Evaluated red-ear sunfish female X green sunfish male and the reverse hybrid for their ability to consume rams-horn snails. Initiated a 1.5-year study to determine the longevity of Bolbophorus daminificus, a catfish trematode, in the flesh of channel catfish. Developed a standardized methodology to determine the antibiotic susceptibility of Flavobacterium columnare by microdilution. Evaluated the efficacy of potassium permanganate in vivo as a therapeutant and prophylactic treatment against sub-acute columnaris on catfish. Diquat efficacy was evaluated in vivo against an acute experimental F. columnare infection in channel catfish. Copper sulfate was evaluated as a therapeutant and as a prophylactic treatment against columnaris in channel catfish. Manuscripts have been submitted to or accepted by peer-reviewed journals (ARIS #190798, 221268, 221758, 219919, 217437, 217436, 213203, 218691). (NP 106, Component 4b)

Conducted a pond study to examine the impact of paddlefish on channel catfish production ponds. Conducted a pond study to compare production characteristics of channel catfish to channel X blue hybrid catfish when fed full or restricted rations. Conducted a study on the stocking density of NWAC 103 strain channel catfish on production characteristics and rearing unit water quality in lined raceways. Initiated a follow-up study (based on results of the above study) with the addition of a diffuser grid in each raceway to improve water quality and increase production rates. Manuscripts have been submitted to or accepted by peer-reviewed journals (ARIS #220024, 224888). (NP106, Component 7b)

Conducted a study to evaluate effects of hauling density on golden shiners. Conducted a field trial of a grading device for use in rectangular holding vats. Developed a method for estimating oxygen needs of catfish during transport and a method to evaluate a grading process. Manuscripts have been submitted to or accepted by peer-reviewed journals (ARIS #220027, 220588, 228923). (NP106, Components 7e and 9a)


4.Accomplishments
1. FDA-REQUIRED LABORATORY STUDY ON THE SAFETY OF COPPER SULFATE TO CATFISH EGGS: The margin of safety for using copper sulfate to control fungus on catfish eggs is unknown, but required as a component of the FDA-approval process. A Target Animal Safety study was completed that demonstrated that the proposed recommended treatment (10 mg/L) was safe for treating catfish eggs daily. Also demonstrate that 3 or 5 times the recommended treatment was safe for treating catfish eggs daily. These studies are required by FDA for a future label claim. The impact will be to complete a major component of the approval process, thereby improving the economics of the industry by providing another legal means to increase survival rates in catfish hatcheries. (NP-106, Component 4b)

2. TANK TREATMENT FOR ICHTHYOBODA INFESTING SUNSHINE BASS: Commercially raised sunshine bass held in tanks and infested with the protozoan parasite ichthyoboda (costia) undergo high mortality. The efficacy of bath treatments of copper sulfate and potassium permanganate were evaluated on fish with a heavy ichthyoboda infestation. The efficacious doses were determined and results indicate that bath treatments of copper sulfate nearly eliminated the parasite. The impact will be an economic benefit by allowing producers to intensively raise more fish to a harvestable size with a low-cost, more effective treatment. (NP 106, Component 4b)

3. COPPER SULFATE AND POTASSIUM PERMANGANATE HAVE A PROPHYLACTIC EFFECT ON COLUMNARIS-EXPOSED CATFISH: Copper sulfate and potassium permanganate were evaluated as therapeutants and as a prophylactic treatment against F. columnare infection in channel catfish. The studies clearly demonstrated the prophylactic effect, but the therapeutic effect was limited under experimental conditions. Copper sulfate produced 90% reduction in the bacterial colony-forming units count of the water. Understanding the benefits and the limitations of these compounds is essential for developing effective control methods for columnaris, one of the two most costly diseases to the channel catfish industry in the United States. (NP 106, Component 4b)

4. FDA-REQUIRED FIELD STUDY ON USING COPPER SULFATE TO CONTROL FUNGUS ON CATFISH EGGS: This research addresses egg mortality from fungus (i.e., watermolds) aggressively destroying eggs in catfish hatcheries. A field dose-confirmation study in cooperation with a local hatchery was completed that demonstrated a statistical difference between treating catfish eggs daily with 10 ppm copper sulfate and a sham treatment. This field study was required by FDA for a future label claim. The impact will be to improve the economics of the industry by providing increased survival rates in catfish hatcheries. (NP106, Component 4b)

5. FUNGUS TREATMENTS FOR CATFISH EGGS INCUBATED IN HATCHING TROUGHS: Water molds or fungi can destroy entire egg masses in hatching troughs and potentially cause producers to have a shortage of catfish fingerlings. Hydrogen peroxide and formalin were applied as flow-through treatments and evaluated on egg masses that were naturally infected with fungus. Both compounds were observed to lower the incidence and intensity of fungi and to produce a higher egg survival; the highest survival and lowest incidence of fungi was at 250 mg/L hydrogen peroxide and 400 mg/L formalin, about 30% of the label rate. This accomplishment demonstrates that farmers can use much lower concentrations (of either chemical) than the recommended label rate and still maintain effective treatment for controlling fungal infestations on catfish eggs. The impact will be an economic benefit by allowing producers to hatch more eggs, use less of these costly chemicals, and avoid shortfalls in their fingerling production quotas. (NP 106, Component 4b)

6. EFFECTS OF HARVESTING/HAULING ON BLOOD PHYSIOLOGY/FILLET QUALITY OF CATFISH: Handling can affect the health of the fish and cause the fillets to be of low quality. Investigation showed that harvest and transport caused significant elevation in the stress response of food-size channel catfish. Results indicate that routine capture and hauling procedures are stressful to commercially produced food-size channel catfish and that using liquid oxygen for aerating fish in holding socks does not significantly improve fillet quality or reduce stress levels. The impact of this research provides stakeholders with a means by which they can plan, monitor, and evaluate critical aspects of harvest and transportation of live fish. (NP-106, Component 9a)

7. SENSITIVITY OF BACTERIA TO DIQUAT DETERMINED: New chemicals to control bacterial infections in cultured fish are sorely needed. The in vitro efficacy of Diquat against F. columnare isolates was assessed. Isolates were sensitive to Diquat at =5mg/L. These findings will lead to effective treatment protocols for F. columnare infections, one of the two most costly infections to the channel catfish industry in the United States. (NP-106, Component 4b)

8. CATFISH NET YIELD INCREASES LINEARLY: Net yield of catfish in intensively managed earthen ponds is well documented, but new technologies are sought to increase yields. A prototype combined photoautotrophic-chemoautrophic production system used to investigate intensified production at increased stocking rates resulted in net yields that increased linearly as stocking rate increased. This research demonstrated that increased channel catfish yield was possible by using the prototype combined photoautotrophic-chemoautrophic production system. (NP 106, Component 7b)

9. EFFECTS OF LOADING DENSITIY ON GOLDEN SHINERS DURING TRANSPORT: Live-haulers typically transport golden shiners at a density of 1 lb fish/gal water. Oxygen requirements during the transport of live fishes were investigated and resulted in development of a dissolved oxygen management model for aquaculture. Results indicated that successful transportation of golden shiners at twice the typical rate is possible. The impact is that this research mitigates the increasing transportation cost and will economically benefit the baitfish industry. (NP-106, Component 7e)


6.Technology Transfer

Number of Non-Peer Reviewed Presentations and Proceedings17

Review Publications
Straus, D.L. 2008. Copper sulfate toxicity to channel catfish fry: Yolk sac versus swim-up fry. North American Journal of Aquaculture. 70(3):323-327.

Griffin, B.R., Mitchell, A.J. 2007. Susceptibility of channel catfish, Ictalurus punctatus, to Edwardsiella ictaluri challange following copper sulfate exposure. Journal of Fish Diseases. 30:581-585.

Mitchell, A.J., Snyder, S.G., Wise, D., Mischke, C. 2007. Evaluating slurried-hydrated lime pond-shoreline treatments for reducing populations of rams-horn snails. North American Journal of Aquaculture. 69:313-316.

Mitchell, A.J., Hobbs, M., Brandt, T. 2007. The effect of chemical treatments on Melanoides tuberculatus, and exotic snails that serve as vectors of trematodes to fish and other species in the United States. North American Journal of Fisheries Management. 27:1287-1293.

Green, B.W. 2007. Stocking strategies for production of Litopenaeus vannamei (Boone) in amended freshwater in inland ponds. Aquaculture Research. 39:10-17.

Green, B.W., Popham, T.W. 2008. Probabilities of low nighttime temperatures during stocking and harvest seasons for inland shrimp culture. Journal of the World Aquaculture Society. 39:91-103.

Min, B., Green, B.W. 2008. Use of microbial transglutaminase and non-meat proteins to improve functional properties of low NaCl, phosphate-free patties made from channel catfish (Ictalurus punctatus) belly flap meat. Journal of Food Science. 73(5):E218-E226.

Minchew, D., Beecham, R., Pearson, P.R., Green, B.W., Kim, J., Bailey, S. 2007. The effects of harvesting and hauling on the blood physiology and fillet quality of adult channel catfish. North American Journal of Aquaculture. 69(4):373-380.

Darwish, A.M., Mitchell, A.J., Hobbs, M.S. 2008. In vitro and in vivo evaluation of potassium permanganate treatment efficacy for the control of acute experimental infection of flavobacterium columnare in channel catfish. North American Journal of Aquaculture. 70:314.322.

Last Modified: 9/23/2014
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