Turkey's Ghrelin Gene Sequenced

A gene that may play a key role in regulating feed intake and energy expenditure in turkeys has been sequenced by Agricultural Research Service scientists. The gene codes for the production of ghrelin, a hormone that affects appetite in birds and mammals.

ARS animal scientist Mark Richards and colleagues at the ARS Growth Biology Laboratory in Beltsville, Md., sequenced the entire ghrelin gene in turkey and deposited the sequence in GenBank, the international repository for gene sequences of birds, mammals and other organisms.

Poultry producers have selected turkey and chicken lines that grow faster and produce more meat, but these commercial birds tend to overeat when given free access to feed. This can lead to obesity and other health-related problems if the birds are not put on a strict dietary regimen.

That's why scientists want to learn more about the factors that control poultry appetite. They know that specific centers of the brain--the brain stem and the hypothalamus--are involved in the regulation of appetite and energy metabolism. Both feed intake and energy balance are orchestrated by biochemical processes involving enzymes, hormones and other types of proteins, each the product of a unique gene.

But scientists do not yet have a complete understanding of the genetic basis for the regulation of these functions in turkeys or chickens. A better understanding of these genes and how they are regulated by nutritional and hormonal inputs will help researchers improve poultry breeding and management practices.

Next, Richards will look at mammalian genes that influence appetite and energy balance and will seek the equivalent genes in turkeys and chickens. Finding similar genes may provide scientists with an understanding of the turkey's basic biological systems, allowing better breeding and management practices and leaner birds.

ARS is the U.S. Department of Agriculture's chief scientific research agency.