Event Abstract Back to Event IMPACT OF RETINAL DEGENERATION ON MELATONIN AND GONADOTROPIN INHIBITORY HORMONE LEVELS DURING PHOTOSTIMULATION IN SMOKY JOE CHICKENS Gregoy Y. Bedecarrats1*, Jason Fleming1, Takayoshi Ubuka2, Yoshihisa Hasegawa3 and Kazuyoshi Tsutsui2 1 University of Guelph, Animal and Poultry Science, Canada 2 Waseda University, Biology, Japan 3 Kitasato University, Reproductive Endocrinology, Japan In avian species the reproductive axis is controlled by stimulatory (GnRH) and inhibitory (GnIH) inputs. Light stimulates the synthesis and release of GnRH via hypothalamic photoreceptors, and indirectly controls GnIH production by altering melatonin (Mel) synthesis from the retina and pineal gland. Recently, we reported that blind roosters from the Smoky Joe strain of chickens mature sexually earlier than sighted animals. Thus, in the present study we investigated if the lack of functional retina impacts Mel and GnIH levels. Smoky Joe roosters were maintained on a short-day photoperiod (8h/SDP) until 18 wks of age then transferred to a long-day photoperiod (14h/LDP). At 18 (SDP) and 24 (LDP) wks of age, blood samples were collected every 4h for 24h from 10 blind and 10 sighted birds. Additionally, for both collection ages, pineal, retina and diencephalons were collected from 5 blind and 5 sighted birds in the middle of the dark and light phases. In blind birds, retinal Mel levels were low in all samples while in sighted birds, they were significantly increased during the dark phase under SDP but not LDP. Pineal Mel content was significantly higher during the dark than the light phase for both blind and sighted animals under SDP. Interestingly, under LDP, pineal Mel content in sighted roosters was significantly lower than those observed under SDP. Despite the difference observed in the retina and pineal, plasma Mel profiles were identical between blind and sighted birds with a significant increase during dark phases under both SDP and LDP. Levels of GnIH in the diencephalon mirrored those observed for Mel in the pineal gland with decreased levels during light phases in both blind and sighted birds, and lower levels during dark phase in sighted roosters under LDP. Our data indicate that although Mel and GnIH follow a circadian rhythm in both blind and sighted roosters, a functional retina results in decreased pineal Mel and hypothalamic GnIH during LDP dark phases. Acknowledgements This work was supported in part by the Poultry Industry Council, the Natural Sciences and Engineering Research Council of Canada, and the Ontario Ministry of Agriculture, Food and Rural Affairs. Keywords: chicken, GnIH, Melatonin, Reproduction Conference: NASCE 2011: The inaugural meeting of the North American Society for Comparative Endocrinology, Ann Arbor, United States, 13 Jul - 16 Jul, 2011. Presentation Type: Poster Topic: Neuroendocrine control of reproduction Citation: Bedecarrats GY, Fleming J, Ubuka T, Hasegawa Y and Tsutsui K (2011). IMPACT OF RETINAL DEGENERATION ON MELATONIN AND GONADOTROPIN INHIBITORY HORMONE LEVELS DURING PHOTOSTIMULATION IN SMOKY JOE CHICKENS. Front. Endocrinol. Conference Abstract: NASCE 2011: The inaugural meeting of the North American Society for Comparative Endocrinology. doi: 10.3389/conf.fendo.2011.04.00004 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 11 Jul 2011; Published Online: 09 Aug 2011. * Correspondence: Dr. Gregoy Y Bedecarrats, University of Guelph, Animal and Poultry Science, Guelph, N1G 2W1, Canada, gbedecar@uoguelph.ca Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Gregoy Y Bedecarrats Jason Fleming Takayoshi Ubuka Yoshihisa Hasegawa Kazuyoshi Tsutsui Google Gregoy Y Bedecarrats Jason Fleming Takayoshi Ubuka Yoshihisa Hasegawa Kazuyoshi Tsutsui Google Scholar Gregoy Y Bedecarrats Jason Fleming Takayoshi Ubuka Yoshihisa Hasegawa Kazuyoshi Tsutsui PubMed Gregoy Y Bedecarrats Jason Fleming Takayoshi Ubuka Yoshihisa Hasegawa Kazuyoshi Tsutsui Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.