Issue 4, April 2000
About this Newsletter

Meeting the Challenges of Keeping Aquatic Animals Healthy

Among agriculturally important animals, fish pose unique challenges for maintaining health. More than 50 diseases affect fish and shellfish cultured in the United States, and managing diseases and parasites is one of the industry’s highest priorities. ARS supports about two dozen scientists in three main laboratories that work together to support fish health.

ARS researchers study how fish transmit and contract disease in their watery surroundings. For example, current research indicates that the bacterium Streptococcus iniae likely enters the fishes’ nostrils through the water. Also, parasitic worms that can infect fish can pass from birds who feed on the fish into the ponds. The worms then develop in aquatic snails, then enter the fish.

Understanding such complex relationships helps scientists devise the best approach to disease control. Much of the work at ARS’ Aquatic Animal Health Research Laboratory in Auburn, Alabama, focuses on vaccine development. A new vaccine for S. iniae reduced mortality in tilapia and hybrid striped bass by more than 80 percent in the laboratory. Another recent success was the first approved modified live-bacterium fish vaccine to protect young channel catfish from enteric septicemia.

The Auburn staff works closely with geneticists in Stoneville, Mississippi, to improve fishes’ natural ability to resist disease. To date, genetic improvement in agriculture has focused on livestock, poultry, and crops. Now ARS researchers hope to bring both traditional breeding and molecular biology to bear on disease management in aquatic systems.

ARS has a long history of helping fish farmers deal with parasites. Researchers in Stuttgart, Arkansas, conduct experiments to support regulatory approval of compounds such as copper sulfate and potassium permanganate that can be added to the water to reduce parasites. That’s important because few chemicals are approved to treat diseases and parasites. Water-based treatments are often more effective because ill fish don’t eat, so medication can’t be delivered effectively through food.

Other research projects include developing diagnostic tests for important diseases, characterizing the fish immune system, and improving nutrition for cultured aquatic animals.

For more information, visit the web site describing this national program.

Or contact any of the following:

Phillip Klesius, Auburn, AL
Donald Freeman, Stuttgart, AR
William Wolters, Stoneville, MS

Research Briefs

Growth charts of sunshine bass and zooplankton developed by ARS scientists help aquaculturists protect their fish by stocking them at a precise time when they can grow fast and not become prey to the zooplankton.
Gerald M. Ludwig
(870) 673-4483

To improve piglet health and growth after weaning, ARS researchers are comparing the immune system responses of piglets fed spray-dried plasma to those without the supplemental protein. Piglets fed the plasma showed evidence of being better able to resist infections.
Jeffery A. Carroll
(573) 882-6261

The first animal model to study tuberculosis spread in white-tailed deer, developed by ARS scientists, has allowed researchers to find that deer saliva, nasal secretions, urine, and feces contain the disease organism. That’s helping them define how infected deer spread TB and should help eradication efforts.
Diana L. Whipple
(515) 663-7325

A new, ARS-designed air-cleaning system reduced Salmonella by 94 percent in a commercial poultry hatchery.
Bailey W. Mitchell
(706) 546-3443

Insectary leftovers make nutritious cattle feed, ARS and University of Hawaii scientists found. The mix, based on wheat germ or corn cobs, is originally used to raise sterile fruit flies for insect control programs.
Eric. B. Jang
(808) 959-4300

ARS laboratory experiments showed that sodium carbonate kills E-coli and other harmful microbes in cow manure. This finding could lead to a cost-effective way to improve livestock and human health.
James B. Russell
(607) 255-3904

Entomologist Edward F. Knipling died March 17 at his home. Knipling pioneered the sterile male insect technique that led to eradication of the wild screwworm population in the United States, Mexico and parts of Central America.

Awards

These ARS researchers have been honored recently for their achievements:

ARS Scientist of the Year Awards:

Phillip H. Klesius, Aquatic Animal Health Research Laboratory, for outstanding research to improve the health of farm-raised fish.

Ann M. Donoghue, Germplasm and Gamete Physiology Laboratory, for significant contributions in understanding turkey sperm function, physiology, preservation, and quality.

Robert A. Bellows, Ft. Keogh Livestock and Range Research Laboratory, named Outstanding Agricultural Leader of Montana by Montana State University for exceptional research contributions in beef cattle physiology and reproduction.

Eric P. Hoberg, , Biosystematics and National Parasite Collection Unit, appointed Museum Affiliate to the University of Alaska’s Mammalogy Department.

Jeffrey A. Carroll, Robert L. Matteri, Cheryl J. Dyer, Animal Physiology Research Unit, awarded the National Pork Producers 2000 Award for Innovative Basic Research.

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