Scientists Study Excess Fat in Chickens
January 23, 2008
Obesity is a problem for many
American consumersand now even chickens are getting fat. As a result,
Agricultural Research Service (ARS)
scientists have been looking for ways to help growers efficiently produce
chickens of optimal weight while minimizing excess fat.
Animal Biosciences and Biotechnology Laboratory in Beltsville, Md., animal
Richards, along with research leader
McMurtry and Penn State University
collaborator Ramesh Ramachandran, recently identified and sequenced genes
responsible for regulating both energy use by individual cells and the food
intake of birds. They also showed that the genes function in different tissues
throughout the body of the broiler chicken.
This important biochemical pathway, previously discovered in other animals,
maintains energy balance in the birds body. A key component of the
pathway is an enzyme called AMP-activated protein kinase, or AMPK.
In all animals, obesity results from an imbalance that occurs when more food
energy (calories) is consumed than the body actually needs. The excess energy
is stored mostly as fat. Over the years, in response to a growing worldwide
consumer demand, poultry breeders have bred chickens that grow faster and
produce more meat. But modern broiler/breeder chickens don't adequately balance
their feed consumption to match their energy requirements. When these birds are
given unrestricted access to feed, they will overeat and become obese.
AMPK plays a central role in sensing cellular energy levels. It begins a
series of events that affect food intake and metabolism of fat, carbohydrate
and protein. According to Proszkowiec-Weglarz, AMPK is really a molecular
fuel gauge and a master metabolic regulator in cells. It responds to
fluctuations in the levels of cellular energy and of specific nutrients and
hormones outside the cells.
more about this research in the January 2008 issue of Agricultural
ARS is the U.S. Department of
Agriculture's chief scientific research agency.