Regulation of Biological Clocks
Dr. Paul A. Bartell
Research in my laboratory focuses on the regulation of biological clocks in birds at the systems level. We use behavioral, molecular, and electrophysiological techniques to understand the neural and endocrine mechanisms by which these daily clocks and yearly calendars control the temporal organization of behaviors and life history stages. Current projects are broadly focused along two categories: (1) We (and others) have determined that biological clocks temporally organize pre-migratory and migratory behaviors. Currently, we seek to identify the changes in protein and gene expression that allows normally diurnal birds to become nocturnally active during migration, yet still function at a high performance level despite having very little sleep. (2) The influence of biological clocks in timing reproduction has been established, yet the proximal mechanisms by which they do so have remained elusive. Our work attempts to identify the signals that the biological clock transmits, amplifies or gates in initiating reproductive development and in maintaining reproductive viability.

Functional and Integrative Genomics
Dr. Guy F. Barbato
The physiological genetics of growth and development has been the focus of our research program. A portion of his work centers on genetic variation in the reproductive aspects of the transmission of genes. Work involving the male reproductive system, specifically genetic relationships of sperm membrane characteristics, has resulted in a novel method to evaluate the fertilizing ability of sperm from a variety of the avian (Pekin duck, turkey and Japanese quail) and the mammalian (rat and mouse) species. Furthermore, we have begun to concentrate on genetic elements of the oocyte. Recent studies have demonstrated the inheritance of a novel protein isolated from the chicken oocyte that accounts for approximately 65 percent of idiopathic female infertility among broiler-type chickens. We are also investigating several environmental and pharmacological agents that influence this family of genes. Continued work will elucidate the mechanisms of action.

Modification of Egg Composition
Dr. Robert G. Elkin
We are interested in the metabolic effects of dietary modification in domestic fowl and their subsequent influence on the composition of poultry products consumed by humans. Specifically, our research centers on the alteration of cholesterol and lipoprotein metabolism in laying hens, with the overall goal of producing consumable eggs with markedly reduced fat and cholesterol contents.

Avian Reproduction and Management
Dr. R. Michael Hulet
We investigate commercial broiler and turkey reproductive problems and opportunities. The program has involved both field research, conducted in collaboration with companies in their hatcheries or breeder operations, as well as university-based studies. Topics include sperm cell management, hatching egg incubation, as well as breeder male and female body weight control. Management studies involving market broilers and turkeys are conducted to determine the environmental and nutritional factors that can optimize growth, meat yield, and carcass quality. All studies involve the immediate application and adoption of research principles to aid the commercial poultry industry.

Skeletal Biology
Dr. Roland M. Leach Jr.
The overall goal of this research program is to develop an understanding of the key physiological processes involved in avian skeletal metabolism. One tissue under investigation is the epiphyseal growth plate, the tissue responsible for longitudinal bone growth. Chondrocytes in this tissue undergo an intricate series of developmental steps culminating in the replacement of cartilage by metaphyseal bone. Disruption of this process can result in a wide variety of skeletal abnormalities such as dwarfism, rickets and tibial dyschondroplasia (TD). The latter condition (TD) is common in rapidly growing broilers and turkeys. Our recent research has utilized gene expression and immunolocalization of gene products to study this skeletal abnormality. The results have led to the development of a hypothesis which explains the pathophysiology of TD. Current research involves the use of microarray technology to gain a wider perspective on gene expression in normal growth plate tissue. A second area of research centers on medullary bone, a tissue that is unique to laying avians and serves as a source of calcium for egg shell formation. In commercial laying hens it provides 30-40% of the calcium in each egg shell. It is our hypothesis that medullary bone has a unique composition which allows for the daily cycling of calcium for egg shell formation. It is well established that medullary bone has different staining properties when compared with normal structural bone. We are in the process of isolating and identifying the matrix components of medullary bone responsible for the different staining and calcium exchange properties of this tissue.

Environmental Management
Dr. Paul Patterson
The central theme of the combined research and extension program is Environmental Poultry Management. Efforts focus on discovering and promoting efficient poultry production systems that place a minimum burden on the environment. While managing manure nutrients, emissions, and by-products of poultry production are obvious endeavors, less tangible efforts include the impact of odor, flies, traffic etc., on the environment at the urban-rural interface. Other efforts emphasize egg production, quality, and food safety.

Molecular Endocrinology
Dr. Ramesh Ramachandran
Our laboratory is interested in characterizing the influence of adipose tissue hormones on avian growth and reproduction. Adipose tissue is considered as an endocrine organ secreting a variety of hormones that are involved in the development of obesity, cardiovascular diseases, diabetes, cancer, and reproductive disorders. Our laboratory has cloned the chicken genes that encode for two adipose tissue hormones, adiponectin and visfatin. We are determining the factors that influence the biological functions and formation of multimeric forms of adiponectin and visfatin. Overall, we are interested in characterizing the physiological role of adiponectin and visfatin on carbohydrate and lipid metabolism, hypothalamic control of pituitary gland function and gonadal functions. Additionally, our laboratory is studying the neuroendocrine control of female reproduction. We are elucidating the role of a novel neuropeptide, gonadotropin-inhibitory hormone, and its receptor in controlling pituitary hormone secretion and ovarian follicular maturation. We use a variety of experimental approaches to study gene and protein expression as well as post-translational modifications at the cellular, tissue and organismal levels.

Metabolic Endocrinology
Dr. Regina Vasilatos-Younken
Our laboratory is interested in the biological actions of growth hormone (GH), with emphasis on components of the signal transduction pathway that are essential for GH action. We have found that chronic GH induces expression of JAK2 protein and tyrosine phosphorylation in liver and skeletal muscles, and that this expression is tissue-specific with respect to JAK2 isoforms. An important focus of our lab is on the metabolic effects of GH, specifically, regulation of hepatic type III iodothyronine deiodinase (5DIII) gene expression, and have found that GH decreases 5DIII message, ultimately resulting in a secondary hyperthyroid state in vivo, with loss of skeletal muscle mass. Although GH has long been recognized to have direct metabolic effects, and is currently administered to non-GH deficient children and adults for therapeutic purposes, the unrecognized consequences for growth or even preservation of muscle mass may be significant. A recent new emphasis in our laboratory, in collaboration with Dr. Ramachandran's laboratory, is the role and regulation of adiponectin in avian models.