Source: PENNSYLVANIA STATE UNIVERSITY submitted to
PHOTOPERIODIC REGULATION OF REPRODUCTION IN THE TURKEY HEN
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
NEW
Funding Source
AFRI COMPETITIVE GRANT
Reporting Frequency
Annual
Accession No.
1025918
Grant No.
2021-67015-34376
Project No.
PENW-2020-02751
Proposal No.
2020-02751
Multistate No.
(N/A)
Program Code
A1211
Project Start Date
May 1, 2021
Project End Date
Apr 30, 2025
Grant Year
2021
Project Director
Bartell, P. A.
Recipient Organization
PENNSYLVANIA STATE UNIVERSITY
408 Old Main
UNIVERSITY PARK,PA 16802-1505
Performing Department
Animal Science
Non Technical Summary
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.
Animal Health Component
0%
Research Effort Categories
Basic
55%
Applied
30%
Developmental
15%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
30532301060100%
Knowledge Area
305 - Animal Physiological Processes;

Subject Of Investigation
3230 - Turkey, live animal;

Field Of Science
1060 - Biology (whole systems);
Goals / Objectives
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: 1) Determine if opsin expression in the brain of the turkey breeder hen changes under photosensitive, egg laying and photorefractory conditions. 2) Determine what areas of the brain are functionally active during photoactivation of the avian reproductive system, during egg laying and during photorefractoriness. 3) Determine if the axon fibers connecting different structures of the brain of the avian change in number or thickness depending upon reproductive state.The PIs will use this information in order to understand how the brains of turkey hens change at different stages of reproduction 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.
Project Methods
The methods our research team will employ are diverse and are outlined below with regards to each individual aim of the project.Determine if opsin expression in the brain of the turkey breeder hen changes under photosensitive, egg laying or photorefractory conditions.We will use immunohistochemistry to identify the location of opsins in the brain of the turkey hen. We will then also compare the location and abundance of the different opsins at photosensitive, egg laying or photorefractory periods of the reproductive cycle. Completing this objective is critical for demonstrating where in the turkey brain light can be sensed, thereby identifying and ruling out possible sites of photoperiodic induction.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 use 2-deoxy-glucoseuptake to determine areas of activity and areas of inactivity within the turkey brain at different stages of the reproductive cycle (photostimulatory, active laying, and photorefractory). These areas of activity and inactivity will then be validated using chronic in vivo electrophysiological techniques.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 perform diffusion tensor imaging (dti), a MRI technique used to determine the direction, number and thickness of the axonal fiber pathways between different structures in the brain involved in the photoperiodic regulation of reproduction and determine whether or not the axonal fiber pathways are modified under different reproductive states.

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


    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