An on-farm detection kit for Salmonella enteritidis has been developed by ARS scientists through a cooperative research and development agreement with Neogen, Inc., of Lansing, MI. The ARS detection kit allows the egg producer to test birds on the premises without costly procedures, which are now necessary. Using monoclonal antibodies developed by ARS researchers, the scientists developed and evaluated a test panel kit for rapidly identifying S. enteritidis organisms isolated from poultry samples. The panel is able to detect S. enteritidis in a diluted egg and chemical mixture spiked with one S. enteritidis organism and then incubated for 24 hours at 37 degrees C. The samples are applied directly to the panel, which looks like a home pregnancy test stick. S. enteritidis is indicated by a blue line on the stick. Fecal and environmental samples taken from infected birds gave similar results. Overall, the panels appear to offer the producer a simple means to identify the presence of S. enteritidis in samples collected at the farm. To confirm the lab findings, scientists will conduct further testing in labs that routinely perform Salmonella testing for egg producers.

Southeast Poultry Research Laboratory, Athens, GA
Peter Holt, (706) 546-3442, pholt@seprl.usda.gov

The recently discovered hormone adrenomedullin can act as an indicator of disease stress in livestock and may be able to serve as a biomarker, ARS scientists have found. The discovery could keep some contamination out of meat processing-and save producers money. Adrenomedullin (AM) is a naturally occurring amino acid peptide hormone produced in many tissues, including the adrenal medulla, lungs, kidneys, and heart. It is involved in many physiological and pathological processes. Increases in the hormone appear to be associated with some forms of infection in cattle, goats, pigs, and sheep, according to the study done in collaboration with the National Institutes of Health. In ARS experiments, calves that harbored internal parasites had 67 percent more AM in their blood than healthy calves. Monitoring of AM levels may give livestock producers the opportunity to help sick animals recover from illness and make them safe for processing, which would be a plus for the producer and the consumer.

Growth Biology Laboratory, Beltsville, MD
Theodore H. Elsasser, (301) 504-8222, elsasser@lpsi.barc.usda.gov

ARS is launching its National Animal Germplasm Program by storing semen from special research lines of chickens at the National Seed Storage Laboratory (NSSL) in Fort Collins, CO. The laboratory, opened in 1958, provides long-term storage of seeds and other reproductive plant material known as germplasm. Today, the location routinely houses nearly 360,000 samples from about 5,000 crop species and their wild relatives. Germplasm—including semen, embryos, and other tissues—from cattle, swine, poultry, sheep, goats, and fish will also be stored at the site as the main repository for livestock. Researchers and producers will be able to access the germplasm to develop new genetic lines or to reintroduce traits that may have been lost. ARS scientists in East Lansing, MI, developed breeding lines of chickens with varying degrees of genetic resistance to viral-induced lymphoid tumors. The chickens have been used to help researchers understand genetic resistance to tumors and to test the efficacy of Marek's disease vaccines. The East Lansing laboratory began storing cryopreserved chicken semen in 1984 and will donate up to half of the samples from each line to the NSSL collection. Researchers with the new program are developing a comprehensive database of the primary characteristics of livestock breeds and breeding lines. Users will be able to evaluate these breeds for genetic merit across varying environments and production systems.

National Seed Storage Laboratory, Fort Collins, CO
Harvey Blackburn, (970) 495-3200, hblackbu@lamar.colostate.edu
Avian Disease and Oncology Laboratory, East Lansing, MI
Larry Bacon, (517) 337-6828, baconld@msu.edu

A new method for mass-producing white blood cells called macrophages has been developed by ARS animal scientists. Now, instead of obtaining them by flushing precursor cells called monocytes from an animal's lungs or peritoneal cavity, biomedical and veterinary scientists can culture macrophages using small blood or tissue samples. The amoebalike macrophages originate in bone marrow and reside in various tissues as a first-line defense against germs that cause infection or disease. They do this by absorbing germs and then adorning themselves with pieces of digested protein. This helps mobilize immune system "T" cells and "B" cells, which make antibodies. But one swine pathogen, called porcine reproductive and respiratory syndrome virus (PRRSV), infects macrophage cells so it can replicate and spread. In pigs, this can cause late-term abortions, stillbirths, and other problems. With macrophage culturing, scientists can accelerate research aimed at finding new drugs that might target weaknesses in the virus' biological machinery. In pigs, the approach calls for culturing monocyte cells from blood samples and a layer of feeder cells that promotes growth. After several weeks, the monocytes mature into hundreds of millions of healthy, dividing macrophages that can either be stored or harvested for immediate research.

Gene Evaluation and Mapping Research Laboratory, Beltsville, MD
Neil Talbot, (301) 504-8216, ntalbot@lpsi.barc.usda.gov