Progress 10/01/04 to 09/30/09
Outputs
OUTPUTS: Research has been focused on the laying hens metabolic and reproductive response to heat stress. Three strains of laying hens from the worlds major genetic source of laying hens were tested for response to heat stress. Specific measurements of intestinal calcium uptake in the different strains of laying hens in response to heat stress was conducted. PARTICIPANTS: Dr. Mary Beck, Dept. Head Animal Science, Clemson University, Clemson, South Carolina. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Heat stress response is less strenuous in the Hy-line brown leghorn strain compared to the Hy-line white strains (W-36 and W-98). Intestinal calcium uptake was inhibited during heat stress in all 3 strains of hens and more so in the white strains. Production of 3B-HSD in granulosa cells treated with LH, FSH or prolactin were affected by heat stress in laying hens.
Publications
- Taira, H and MM Beck, 2005. Activity of 3B-HSD in granulose cells treated in vitro with LH, FSH, PRL or a combination. Poultry Sci. 84(suppl.1):55
- Taira, H and MM Beck, 2006. 3B-HSD and cAMP in granulosa cells of laying hens subjected to heat stress. Poultry Sci. 85(suppl. 1)
- Franco-Jimenez, DJ and MM Beck, 2005. Intestinal calcium uptake, shell quality and reproductive hormone levels in three laying hen varieties after prolonged egg production. International J of Poult Sci. 4:8:518-522.
- Taira, H and M. M. Beck, 2006. Activity of Three-B-Hydroxysteroid Dehydrogenase in Granulosa Cells Treated in Vitro with Luteinizing Hormone, Follicle-Stimulating Hormone, Prolactin, or a Combination Poult. Sci. 85: 1769-1774.
- Franco-Jimenez, DJ, SE Scheideler, RJ Kittok, TM Brown-Brandl, H Taira and MM Beck, 2007. Differential effects of heat stress in three strains of laying hens. J. Appl. Poult. Res. 16: doi:10.3382/japr.2005-00088
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Progress 10/01/07 to 09/30/08
Outputs
OUTPUTS: Two studies were conducted and completed in 2008 to investigate the effects of trace mineral or vitamin supplementation on eggshell strength and bone strength in laying hens. The first trial investigated inorganic versus organic zinc and manganese supplementation on older hens eggshell strength. The second trial investigated supplementation of selenium for organic vs. inorganic source with or without vitamin E supplementation on egg shell formation and strength. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Poultry Producers PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Supplemental zinc, particularly from the inorganic source, improved long term eggshell strength. Effects on bone etiology are still being explored in the laboratory. Supplemental selenium or vitamin E had mixed effects on eggshell strength.
Publications
- Scheideler, S.E., T. Weber, S. Shields and H. Stilborn, 2008. Effects of trace mineral supplementation on egg production and feathering in laying hens. Poultry Sci. 87:176-177. (Abstract).
- Aljamal, A.A., M.K. Masadeh and S.E. Scheideler, 2008. Vitamin E and selenium supplementation in laying hens. Poultry Sci. 87:50 (Abstracts)
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Progress 10/01/06 to 09/30/07
Outputs
OUTPUTS: Several trials have been conducted testing level of calcium and phosphorus in laying hen diets and source of dietary calcium (large vs. small particle limestone) and their effects on osteoporosis and eggshell integrity in laying hens. Information from these trials has been presented at Poultry Science Association meetings and are being prepared for manuscript submission to Poultry Science.
PARTICIPANTS: Dr. Mohammed Jalal Ms. Patricia Weber
TARGET AUDIENCES: Commercial egg producers Poultry Nutritionists
Impacts
It has been shown that at least 25% large particle size limestone must be present to prevent a loss of bone ash and to maintain eggshell quality. Feeding higher levels of calcium do not necessarily prevent loss of bone mass.
Publications
- Scheideler, S.E., M.J. Jalal, and T. Weber, 2006. Laying hen strain differences in calcium and phosphorus needs. Poultry Sci. 85:178 (Supplement)
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Progress 10/01/05 to 09/30/06
Outputs
Bone sections of W36 and W98 hens were scanned and subjected to analysis by ScionImage software. Cortical and medullary compartments were compared. Statistical analysis is underway currently. Bones from 20 and 60 wk old W98 and W36 hens were frozen in liquid nitrogen and RNA was extracted. Primers to the estrogen receptor were obtained and real time PCR is being conducted.
Impacts
Differences between strains as hens age from 20 to 60 wk of age in relative amounts of cortical (structural) bone and expression of mRNA of the estrogen receptor would be markers that could be used in breeding programs to select for skeletal integrity.
Publications
- Franco-Jimenez, DJ and MM Beck, 2005. Intestinal calcium uptake, shell quality and reproductive hormone levels in three laying hen varieties after prolonged egg production. International J of Poult Sci. 4:8:518-522.
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Progress 10/01/04 to 09/30/05
Outputs
In order to determine effects of age, strain, body weight, and diet on bone integrity of laying hens, two strains of Hy-Line birds, W36 and W98, were started as chicks receiving NRC requirement diets or a diet supplemented with HyD. Chicks were fed to achieve target body weight or 15% greater or less than that target weight. Bones were sampled at 20 and 60 weeks of age. The right tibia from two birds in each treatment was removed, cleaned, decalcified, cut into eight pieces (two halves of the proximal head, four pieces of the shaft, two halves of the distal end), embedded in paraffin, sectioned at 7um, and stained with Hematoxylin and Eosin. Two slides per bird were used for histological examination and measurement of cortical bone diameter and percent trabecular bone. Cortical diameter (CD) was measured at one location on both sides of the bone; percent trabecular bone (%TB) was obtained by dividing traqbecular area by total bone area. Measurements were made using
Scion Image Analysis Program. Data was analyzed using SAS. Comparisons were age (A), strain (S), body weight (BW), and diet (D). For cortical bone, there were effects when comparing age, SxBW, SxD, and AxSxBWxD. At 60 wk, CD was less than at 20 wk (P=0.0001). At 20 wk, addition of HyD enhanced CD in W36 birds but not in W98. At 60 wk, there was no effect of D but W98 birds had greater CD than W36 birds (P=0.0175). For %TB, there were effects when comparing A, SxBW, D, AxBW, AxSxBW, SxD, BWxD, and AxSxBWxD. Considering the most complex interaction, it appeared that age, strain and body weight contributed most to percent trabecular bone; and overall, diet had a relatively small effect.
Impacts
A better understanding of bone characteristics in different strains of laying hens will lead to a better ability to both select for and manage for increased strength and flexibility.
Publications
- No publications reported this period
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