Progress 05/01/23 to 04/30/24
Outputs
Target Audience:Work outlined in this proposal will uncover the neuronal mechanisms and hypothalamic structures involved in photoperiodic regulation of reproduction in turkey hens. Reproduction in turkeys is initiated by increased daylength and becomes limited by the onset of broodiness, eventually resulting in the termination of egg laying. Hens lose their sensitivity to the reproductively stimulating effects of long days, even under ever increasing daylengths. Loss of productivity is costly, as birds must cared for until coming back into production. In birds, photoperiodic information is sensed directly in the brain by specialized photoreceptors. Although the site(s) of these photoreceptors are unknown, several brain areas have been suggested to house these photoreceptors. The PIs will use immunohistological, autoradiography and MRI techniques to identify the brain areas responsible for light sensing and the neuronal pathways that are activated during photostimulation to carry photic information to the pituitary. The PIs will also record electrical activity from neurons in the brains of awake birds in order to understand the type of neuronal signals produced and the neurons involved in their production in order to provide a target for future modulation of reproductive activity. The PIs will also compare these brain areas prior to photoperiodic activation, during egg laying, and during broodiness in order to understand how the brains of turkey hens change to regulate the reproductive cycle in turkeys. Our findings will permit the development of strategies for alleviating production inefficiency due to the limited lay period resulting from photoperiodic insensitivity. Changes/Problems:We had an improper gradient signal that was determined to be from the coil; we had to send the coil to be repaired and are waiting for its return in order to continue our MRI studies. What opportunities for training and professional development has the project provided?The project has provided training and professional development for three undergraduate students and one doctoral student. In addition a lab rotation was provided for two additional PhD students in the Biomedical Physiology Graduate Program. The training provided included aspects of turkey hen husbandry, tissue collection, as well as various technical laboratory applications and processes. How have the results been disseminated to communities of interest?We have disseminated information by providing a seminar, a podcast on the regulation of production in birds, and have submitted an article for publication. What do you plan to do during the next reporting period to accomplish the goals?We plan to do the following in order to pursue our goals of the project, 1) Determine if opsin expression in the brain of the turkey breeder hen changes under photosensitive, egg laying and photorefractory conditions. We will continue performing immunohistochemistry against opsins, tyrosine hydroxylase, and other neuronal markers. on the sliced brain specimens. 2) Determine what areas of the brain are functionally active during photoactivation of the avian reproductive system, during egg laying and during photorefractoriness. We will finishour analysis of the brains from turkey hens that have been given a one hour pulse of light and are photosensitive, actively laying or are photorefractory. 3) Determine if the axon fibers connecting different structures of the brain of the avian change in number or thickness depending upon reproductive state. We will finish imaging the brains from turkey hens that are photosensitive, actively laying, or are photorefractory using MRI and then analyze these data.
Impacts
What was accomplished under these goals?
In the past year we have done the following in pursuit of the goals of the project, 1) Determine if opsin expression in the brain of the turkey breeder hen changes under photosensitive, egg laying and photorefractory conditions. We have collected all of the tissues that we need for completing this specific Aim. We have been performing immunohistochemistry against opsins, tyrosine hydroxylase, and other neuronal markers. We also validated additional antibodies for immunohistochemistry in turkeys. 2) Determine what areas of the brain are functionally active during photoactivation of the avian reproductive system, during egg laying and during photorefractoriness. We finished collecting brains from turkey hens that were actively laying eggs and turkey hens that were photorefractory with regressed ovaries after birds from each group had been given a one hour pulse of light. We processed the brains for imaging of areas with more metabolic activity. We are also conducting immunohistochemistry for Immediate Early Gene Expression. 3) Determine if the axon fibers connecting different structures of the brain of the avian change in number or thickness depending upon reproductive state. We updated our protocols to make our technique more sensitive. This included determining the best concentration of contrast agent and modified the substrate for the MR protocols. We are waiting for the return of our fixed probe to image the remainder of the brains that we collected.
Publications
- Type:
Other
Status:
Published
Year Published:
2024
Citation:
"How do birds make their eggs?"; Moment of UM; April 26, 2024.
- Type:
Journal Articles
Status:
Submitted
Year Published:
2024
Citation:
"Avian Photoperiodism"; Mendoza, A. & Bartell, P. Submitted to Frontiers in Physiology
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2024
Citation:
Circadian clocks on the edge. Society for Research in Biological Rhythms; San Juan, Puerto Rico. May 18-22, 2024.
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Progress 05/01/22 to 04/30/23
Outputs
Target Audience:Our target audience is broad and includes major turkey producers, smaller poultry farm operations, as well as those individuals who grow backyard turkeys as hobby enthusiasts or for meat. Our target audience also includes scientists and STEM students interested in understanding how photoperiodism and broodiness is regulated in birds in general, and turkeys, in specific. This audience includes the readers of our findings in technical journals and non-technical bulletins. Changes/Problems:We had setbacks from the upgrade of our high field MRI facility at Penn State. The gradients for the equipment and the software needed to run the equipment were to be replaced, but because of a backlog, this upgrade took close to one year. We are now able to continue with our imaging as needed to complete the experiments. What opportunities for training and professional development has the project provided?The project has provided training and professional development for three undergraduate students and one doctoral student. This training included aspects of turkey hen husbandry, as well as technical laboratory applications and processes. How have the results been disseminated to communities of interest?We have disseminated information by providing a seminar on the photoperiodic regulation of reproduction in the turkey hen to graduate and undergraduate students and scientists at NC State University. Dr. Bartell also made a teaching video for undergraduate students which explores the anatomy of the avian reroductive system. What do you plan to do during the next reporting period to accomplish the goals?We plan to do the following in order to pursue our goals of the project, 1) Determine if opsin expression in the brain of the turkey breeder hen changes under photosensitive, egg laying and photorefractory conditions. We will continue sectioning the brains for immunohistochemistry and complete our immunohistochemistry survey for opsins on the sliced brain specimens. 2) Determine what areas of the brain are functionally active during photoactivation of the avian reproductive system, during egg laying and during photorefractoriness. We will finish our survey of the brains from turkey hens that have been given a one hour pulse of light and are photosensitive, actively laying or are photorefractory. 3) Determine if the axon fibers connecting different structures of the brain of the avian change in number or thickness depending upon reproductive state. We will image the brains from turkey hens that are photosensitive, actively laying, or are photorefractory using MRI and then analyze these data.
Impacts
What was accomplished under these goals?
In the past year we have done the following in pursuit of the goals of the project, 1) Determine if opsin expression in the brain of the turkey breeder hen changes under photosensitive, egg laying and photorefractory conditions. We collected brains from turkey hens that were actively laying eggs and turkey hens that were photorefractory with regressed ovaries. We processed and prepared these brains for immunohistochemistry. We also validated additional antibodies against opsins for immunohistochemistry in turkeys. 2) Determine what areas of the brain are functionally active during photoactivation of the avian reproductive system, during egg laying and during photorefractoriness. We collected brains from turkey hens that were actively laying eggs and turkey hens that were photorefractory with regressed ovaries after birds from each group had been given a one hour pulse of light. We processed the brains for imaging of areas with more metabolic activity. 3) Determine if the axon fibers connecting different structures of the brain of the avian change in number or thickness depending upon reproductive state. We collected brains from turkey hens that were actively laying eggs and turkey hens that were photorefractory with regressed ovaries. We processed the brains from birds from each group for imaging with MR.
Publications
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Progress 05/01/21 to 04/30/22
Outputs
Target Audience:Our target audience is broad andincludes major turkey producers, smaller poultry farm operations, as well as those individuals who grow backyard turkeys as hobby enthusiasts or for meat. Our target audience also includes scientists and STEM students interested in understanding how photoperiodism and broodiness is regulated in birds in general, and turkeys, in specific. This audience includes the readers of our findings in technical journals and non-technical bulletins. Changes/Problems:Major problems included shutdown of research facilities during COVID, as well as the lack of personnel availability due to COVID. We encountered difficulties due to the moving of our research lab into a new building. This required shutting the lab down, spending several weeks packing the lab, moving eqipment, and setting the lab back up. No work could be completed during this time. We also had unanticipated setbacks due to the migratioin of computer files to a new server system. Although told nothing would be lost, many files were, and these files included protocols that had to be rewritten. What opportunities for training and professional development has the project provided?The project has provided training and professional development for three undergraduate students and one doctoral student. This training included aspects of turkey hen husbandry, as well as technical laboratory applications and processes. How have the results been disseminated to communities of interest?We have disseminated information by being interviewed for an article in a poultry trade journal and in an extension publication on light perception in the brain of poultry. The firstarticle was targeted to individuals in the poultry industry; the second to individuals in the poultry industry, backyard hobbyists, and owners of small farms. What do you plan to do during the next reporting period to accomplish the goals?We plan to do the following in order to pursue our goals of the project,1) Determine if opsin expression in the brain of the turkey breeder hen changes under photosensitive, egg laying and photorefractory conditions.We will collect brains from turkey hens that are actively laying and from those that are photorefractory. We will process the brains for immunohistochemistry and begin immunohistochemistry for opsins on the sliced brain specimens.2) Determine what areas of the brain are functionally active during photoactivation of the avian reproductive system, during egg laying and during photorefractoriness.We will collect brains from turkey hens that have been given a one hour pulse of light and are actively laying or are photorefractory. We will process the brains for imaging of areas with more metabolic activity.3) Determine if the axon fibers connecting different structures of the brain of the avian change in number or thickness depending upon reproductive state.We will collect brains from turkey hens that are actively laying and from those that are photorefractory. We will process the brains for imaging with MR and begin the process of imaging these brains.
Impacts
What was accomplished under these goals?
In the past year we have done the following in pursuit of thegoals of the project,1) Determine if opsin expression in the brain of the turkey breeder hen changes under photosensitive, egg laying and photorefractory conditions.We collected brains from turkey hens that were photosensitive and prepared these brains for immunohistochemistry. We also validate antibodies against opsins for immunohistochemistry in turkeys.2) Determine what areas of the brain are functionally active during photoactivation of the avian reproductive system, during egg laying and during photorefractoriness.We collected brains from photosensitive turkey hens that hadbeen given a one hour pulse of light. We rocessed the brains for imaging of areas with more metabolic activity.3) Determine if the axon fibers connecting different structures of the brain of the avian change in number or thickness depending upon reproductive state.We collected brains from photosensitive turkey hens. We processed the brains for imaging with MR andvalidated the protocols for imaging these brains.
Publications
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