Location: Warmwater Aquaculture Research Unit
Title: Improving Therapeutic Treatments of Channel and Hybrid Catfish Egg Diseases Author
Submitted to: Catfish Culture Research Symposium
Publication Type: Abstract Only
Publication Acceptance Date: November 27, 2005
Publication Date: February 24, 2006
Citation: Small, B.C. 2006. Improving therapeutic treatments of channel and hybrid catfish egg diseases. Catfish Culture Research Symposium - Catfish Farmers of America Annual Meeting, San Antonio, TX. Technical Abstract: Despite the number of therapeutic agents being used commercially to treat catfish eggs, only one, formalin, is specifically approved by the US-FDA for managing catfish egg diseases. Other therapeutants, such as copper sulfate, hydrogen peroxide, and iodine currently fall under FDA exceptions that allow for their use in catfish hatcheries. Although dosage recommendations for these four chemicals (formalin, copper sulfate, hydrogen peroxide, and iodine) can be found in FDA, scientific, and extension literature, treatment methods often need to be “tweaked” for individual hatcheries because of differences in environmental, physical, and disease parameters, as well as different management techniques. Low hybrid catfish hatching success has also brought to question whether hybrid eggs should be treated differently. Several studies were conducted to improve egg disease management with hydrogen peroxide and to identify effective treatments for improving hybrid catfish hatching success. Prior research in our laboratory conducted at 26 degrees Celsius showed that hydrogen peroxide was as effective as formalin for reducing egg disease and improving hatching success. In fact, we reported a 30% improvement in hatching rate with a once daily 15-minute bath at 250 ppm hydrogen peroxide. Others have recommended higher doses (e.g. 1000 – 2000 ppm); however, those studies were conducted in cooler (22 degrees Celsius) water, suggesting that temperature may affect hydrogen peroxide efficacy. Recent results in our laboratory show that the optimal concentration of hydrogen peroxide for treatment of channel catfish eggs increases at lower temperatures. At 28 degrees Celsius , a 100 ppm solution of hydrogen peroxide was found to yield the highest hatching rates, but at 24 degrees Celsius, 500 ppm yielded the highest hatching rate for channel catfish. Hybrid catfish eggs differ from channel catfish eggs in development, and have a higher proportion of dead eggs as a result of the strip-spawning process. In a series of studies conducted between 26 and 28 degrees Celsius, formalin administered 3 times daily as 15-minute, 100 ppm bath was shown to greatly improve hybrid hatching rates when compared to other therapeutic treatments. The combined results of these studies identify chemotherapeutic treatment regimes for improving channel and hybrid catfish hatching success by as much as 40%.