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Slim Chickens: New Technique To Measure Leptin Activity


  Chicken meat is already lean, but Agricultural Research Service scientists have made a key genetic discovery that could help produce chickens with even less fat.


Chris Ashwell of the agency's Growth Biology Laboratory in Beltsville, Maryland, recently discovered the presence of a protein called leptin in chickens. Leptin has long been associated with obesity but until now had been found only in mammals such as pigs, cows, mice, and humans. As a result, Ashwell and colleagues Mark Richards and John McMurtry developed a technique to study the hormonal activity of leptin in chickens.


Maximizing meat and improving production efficiency are major goals for scientists studying chickens. That's because breeding broiler chickens for growth has resulted in increased fat deposition—and reduced reproductive efficiency—in the birds. "What this means is that obesity is becoming a problem in broiler chickens," Ashwell says.


Ashwell and his team hope to use their technique to find a way to regulate the leptin levels in chickens and reduce the birds' appetites. This would make it easier to manage broiler production and still provide consumers with quality meat, Ashwell explains.


"Commercial industries may eventually use the technique to select birds for feeding behavior that does not affect the growth of young birds," he says.


The technique, perfected by Richards and Ashwell, uses a method called capillary electrophoresis to distinguish and quantify genetic material unique to leptin. The process takes only 8 minutes. The team won an award from Beckman Coulter, Inc., for achievements in capillary electrophoresis with this technique.


Leptin, which regulates appetite and energy expenditure, can lead to extreme obesity, diabetes, and infertility in mammals if the gene for leptin production is defective. Leptin is found in fat tissue of mammals and chickens, but in chickens it's also found in the liver.


"Two areas of importance to producers and consumers are increased chick production and improved animal well-being," says Ashwell. Chicks with a smaller appetite may provide a solution to these concerns."—BySarah Tarshis, formerly with ARS.


This research is part of Animal Production Systems, an ARS National Program (#102) described on the World Wide Web at


Christopher M. Ashwell, Mark P. Richards, and John P. McMurtry are with the USDA-ARS Growth Biology Laboratory, 10300 Baltimore Ave., Bldg. 200, Room 201, Beltsville, MD 20705-2350; phone (301) 504-5061, fax (301) 504-8623.

"Slim Chickens: New Technique To Measure Leptin Activity" was published in the May 2000 issue of Agricultural Research magazine.




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