Scotti Hester's Main Page
Dual-energy X-ray absorptiometry is being used to measure bone mineral density and content of the humerus and tibia of live chickens.
Animal well-being, stress, and environmental physiology.
Dr. Hester's research in poultry welfare for the last five years has focused on osteoporosis in laying hens which is a progressive decrease in mineralized structural bone leading to skeletal fragility and susceptibility to fracture. Dr. Hester and her graduate students have shown that skeletal fragility in aging Leghorns at the end of the second cycle of lay is a serious welfare issue. The percentage of freshly broken bones/bird at the end of processing at 126 wk of age averaged 34% with a range of 0 to 61%. Dr. Hester's lab has validated the use of dual-energy X-ray absorptiometry (DEXA) as a noninvasive tool for monitoring skeletal integrity throughout the life cycle of live birds. Specifically, in vivo bone mineral density (BMD) scans were significantly and positively correlated with bone breaking force and bone ash weight. In addition, as BMD decreased in Leghorns, the incidence of bone breakage increased (r = -0.54, P < 0.05). Following validation, DEXA was used to show that a non-fasting as compared to a fasting molting regimen was less deleterious to skeletal mineralization.
A long-term goal of Dr. Hester's research lab is to improve skeletal integrity in egg-type chickens by genetic selection for improved BMD. Dr. Hester's lab has shown that the coefficient of variation (CV) for BMD of egg-type chickens was greater than 10% after 25 wk of age suggesting that DEXA can be used as an indicator tool in genetic selection with a potential for improving skeletal integrity of birds. In collaboration with Dr. Diane Moody Spurlock, a chicken F2 resource population was generated from layer and broiler genetic lines so as to identify quantitative trait loci (QTL) associated with bone mineralization and strength. Although no significant QTL influencing BMD were detected after adjusting for variation in body weight and egg production, multiple suggestive QTL were found, demonstrating an important genetic regulation of bone strength in chickens. These QTL results suggest that regulation of skeletal integrity may be due to the effects of multiple genes and that each account for relatively small amounts of variation in bone mineralization.
- Dual-energy x-ray absorptiometry (DEXA)
- Mineral analysis
- Inductively coupled plasma atomic emission spectrometry
- Atomic absorption spectrophotometry
Selected Refereed Journal Articles
Schreiweis, M. A., J. I. Orban, M. C. Ledur, D. E. Moody and P. Y. Hester, 2005 Validation of dual-energy X-ray absorptiometry in live White Leghorns. Poult. Sci. 84:91-99.
Mazzuco, H. and P. Y. Hester, 2005. The effect of an induced molt and a second cycle of lay on skeletal integrity of White Leghorns. Poult. Sci. 84:771-781.
Hester, P. Y. 2005. Impact of science and management on the welfare of egg laying strains of hens. Poult. Sci. 84:687-696 (invited symposium paper).
Mazzuco, H. and P. Y. Hester, 2005. The effect of an induced molt using a non-fasting program on bone mineralization of White Leghorns. Poult. Sci. 84:1483-1490.
Mazzuco, H., J. P. McMurtry, A. Y. Kuo, and P. Y. Hester, 2005. The effect of pre- and postmolt diets high in omega-3 fatty acids and molt programs on skeletal integrity and insulin-like growth factor-I of White Leghorns. Poult. Sci. 84:1735-1749.
Schreiweis, M. A., P. Y. Hester, and D. E. Moody, 2005. Identification of quantitative trait loci associated with bone traits in an F2 resource population of chickens. Genetics, Selection, Evolution 37:677-698.
Schreiweis, M. A., P. Y. Hester, P. Settar, and D. E. Moody, 2005. Identification of quantitative trait loci associated with egg quality, egg production, and body weight in an F2 resource population of chickens. Animal Genetics 37:106-112.
Bennett, A. K., P. Y. Hester, and D. E. Moody Spurlock, 2006. Polymorphisms in vitamin D receptor, osteopontin, insulin-like growth factor 1 and insulin, and their associations with bone, egg, and growth traits in a layer - broiler cross. Animal Genetics 37:283-286.
Bennett, A. K., P. Y. Hester, and D. M. Spurlock, 2007. Relationships of a transforming growth factor b single nucleotide polymorphism and mRNA abundance with bone and production traits in chickens. Poultry Sci. 86:829-834.
Zhai, W., S. L. Neuman, M. A. Latour, and P. Y. Hester, 2007. The effect of dietary L-carnitine on semen traits of White Leghorns. Poultry Sci. 86:2228-2235.
Zhai, W., S. L. Neuman, M. A. Latour, and P. Y. Hester, 2008. The effect of in ovo injection of L-carnitine on hatchability of White Leghorns. Poultry Sci. 87: 569-572.
Zhai, W., S. L. Neuman, M. A. Latour, and P. Y. Hester, 2008. The effect of male and female supplementation of L-carnitine on reproductive traits of White Leghorns. Poultry Sci. 87: 1171-1181.
Kim, W. K., T. M. Herfel, C. S. Dunkley, P. Y. Hester, T. D. Crenshaw, and S. C. Ricke, 2008. The effects of alfalfa-based molt diets on skeletal integrity of White Leghorns. Poultry Sci. 87: 2178–2185.
Fanatico, A. C., P. B. Pillai, P. Y. Hester, C. Falcone, J. A. Mench, C. M. Owens, and J. L. Emmert, 2008. Performance, livability, and carcass yield of slow- and fast-growing chicken genotypes fed low-nutrient or standard diets and raised indoors or with outdoor access. Poultry Sci. 87:1012-1021.