Richard E. Austic - Professor
PhD from University of California
Graduate fields: Animal Science, Nutrition
Area(s) of interest: nutritional interactions of amino acids, nutrition and development of the avian embryo
Teaching:
- Nutritional Physiology and Metabolism - AS 410
- American Society for Nutritional Sciences
- Poultry Science Association
- Society for Experimental Biology and Medicine
- World's Poultry Science Association
Email: rea2@cornell.edu
Current Research Interests:
Nutritional interactions of amino acids
The efficiencies by which amino acids are used for physiological processes are markedly influenced in poultry and other simple-stomached animals by the dietary balance of amino acids. Little is known about the molecular mechanisms that control the metabolism of amino acids when the diet does not contain a balanced profile of amino acids. Research in this laboratory focuses on changes in the activities of enzymes of amino acid catabolism that might contribute to inefficient use of amino acids for growth. The current focus is on primary and secondary pathways of phenylalanine metabolism under conditions of dietary phenylalanine imbalance.
Selected References:
Lartey, F. M. and R. E. Austic (2008) Phenylalanine requirement, imbalance, and dietary excess in one-week-old chicks: growth and phenylalanine hydroxylase activity. Poultry Science 87:291-297.
Keene, J. C. and R. E. Austic (2001) Dietary supplements of mixtures of amino acids lacking threonine, phenylalanine or histidine increase the activity of hepatic threonine dehydrogenase, phenylalanine hydroxylase or histidase, respectively, and prevent growth depressions in chicks caused by dietary excesses of threonine, phenylalanine, or histidine. Journal of Nutritional Biochemistry 12:274-284.
Yuan, J.-H, A. J. Davis, and R. E. Austic (2000) Temporal response of hepatic threonine dehydrogenase in chickens to the initial consumption of a threonine-imbalanced diet. Journal of Nutrition 130:2746-2752.
Park, B.-C. and R. E. Austic (1998) Changes in hepatic branched-chain α-keto acid dehydrogenase activity in response to isoleucine imbalance in growing chickens. Journal of Nutritional Biochemistry 9:687-696.
Cholesterol as a nutrient for the developing embryo
The avian egg is a rich source of nutrients, including cholesterol, for the developing chick embryo. It might be possible to reduce the cholesterol content of eggs by genetic manipulation. However, the amount of cholesterol in yolk that is actually needed by the chick embryo is not known. Information on the requirement of cholesterol by the embryo will be vital in any attempt to reduce the cholesterol content of eggs. A technique for replacement of the entire yolk of chick embryos with cholesterol-reduced egg yolk is being used in this laboratory in an attempt to determine the consequences of cholesterol deficiency and to assess the cholesterol requirement of the chick during incubation and the early post-hatch period of growth and development.
Other References:
Hsu, K.-N. and R. E. Austic (2008) Culturing the chick embryo in ovo using cholesterol-reduced egg yolk. Poultry Science 87 (Suppl. 1): Abstract #27759.
Austic, R. E. and K.-N. Hsu (2008) The need for yolk, yolk granules, and cholesterol by the chicken embryo. Poultry Science 87 (Suppl. 1): Abstract #27741.