Turkey's Ghrelin Gene Sequenced
April 30, 2004
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
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.