NCCC097: Regulation of Adipose Tissue Accretion in Meat-Producing Animals (NCR97)
Statement of Issues and Justification
Members of NCR-97 continue to be dedicated to understanding regulation and mechanisms for control of adipose tissue (fat) deposition in animals raised for meat production. Adipose tissue is necessary for survival to supply and store energy and as an endocrine organ. Excess fat is costly to produce and is unwanted by the consumer of lean meat. Growth of animals can be modified to decrease fat production by nutritional, pharmacological and physiological manipulation of intrinsic or extrinsic processes. Members have been major contributors to this area for over 25 years. Today the scope of NCR-97 is national and includes participants from the entire country and from USDA/ARS. Industry representatives are invited to each meeting. Members represent most of those actively researching regulation of fat accretion in meat-producing animals in the USA. This inclusiveness provides total awareness of and supports integration of research. No other multi-state project includes the objectives/goals of those proposed for NCR-97.Thirty years ago, members of NCR-97 were major publishers about carcass composition, adipocyte anabolic and catabolic lipid metabolism, and fatty acid composition. Twenty years ago, members focused on nutritional/pharmacological treatment to change body composition. Ten years ago, mechanisms controlling adipocyte hyperplasia, differentiation, and growth (hypertrophy), and effects of somatotropin and beta-adrenergic agonists were emphasized. Currently, members address problems using cutting edge biology for the 21st century.
For example, control of adipocyte differentiation is studied using DNA and immunological technology to probe the chronology of gene expression. Members cloned full or partial sequences for many porcine and bovine genes associated with adipocyte differentiation. The effect of various hormones, growth factors and nutrients on differentiation continues to be of primary interest. A member cloned the porcine beta-adrenegic receptors (BAR); porcine adipocytes have mostly B1AR and not B3AR, as in rodents. The cloned receptors allow research to understand the unique adrenergic biology of the porcine adipocyte. One member studies the role of the negative adenosine receptor in modulating catabolic porcine adipocyte lipid metabolism. Members continue to delve into signal transduction mechanisms for regulation of adipocyte lipid metabolism and growth. The role of fatty acid oxidation in young pigs and the development and function of brown adipose tissue in newborn cattle and sheep are ongoing interests of two members. Seven members study mechanisms for conjugated linoleic acid modification of growth.
Members provide expertise and major contributions to the knowledge base for regulation of adipocyte differentiation and growth, and lipid metabolism. Classical measurements of enzyme activities, fatty acid composition, and adipocyte size and number are used, but are supplemented by new technologies such as immunological and nucleic acid methods, cellular signal transduction measurements, and microdialysis (to measure metabolites and blood flow in vivo). Molecular, cellular, tissue, organ, or whole animal designs are used as mandated by the question posed. The group has a very strong publication record to disseminate results to scientists of the world. Over the last 4+ years, there are >160 journal articles, >150 abstracts, 11 book chapters, 2 books, and many technical reports. There are 9 joint publications by members representing 4 joint projects. A symposium, "Alternative Aspects of Adipocyte Function" was organized and presented by members of NCR-97 at ASAS-2003. Members have hundreds of thousands of dollars in grants each year from USDA/NRI, commodity groups, industry, and state funds. They serve on multiple journal editorial boards (J. Anim. Sci., J. Nutr., Dom. Anim. Endocrin., Exp. Biol. Med.), serve as Editor and section editors for J. Anim. Sci., review multiple grants, present numerous seminars and symposium talks, and organize and chair meeting sessions and symposia. With the explosion of obesity in humans from developed countries, research results from members impact the biology of adipose tissue growth; some results can be extrapolated to humans or can be used as background for using the pig or other species as biomedical models.
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