Lien R J, Siopes T D
Department of Poultry Science, North Carolina State University, Raleigh 27695-7608.
Poult Sci. 1989 Oct;68(10):1409-17. doi: 10.3382/ps.0681409.
Plasma concentrations of thyroxine (T4), triiodothyronine (T3), and prolactin were determined weekly through an egg laying cycle induced with 30 wk of 14 h light:10 h dark. Egg production, primary remige molting, and occurrence of photorefractoriness were monitored. Hens were assigned to one of two groups; those that exhibited photorefractoriness (PR) and those that remained photosensitive (PS). Weekly plasma T4 concentrations relative to the time of initiation of photostimulation did not differ between PR and PS groups; concentrations peaked prior to the onset of egg production, were lowest during peak egg production, and increased between Weeks 6 and 30 of photostimulation. Plasma T4 levels of PR hens peaked 3 wk prior to the onset of photorefractoriness. Plasma T3 concentrations of PS and PR hens were similar until increases occurred in PR hens at the onset of photorefractoriness. Plasma prolactin levels in PS and PR hens increased after photostimulation, declined sooner in PR hens, and were generally greater in PS than PR hens during the last 20 wk of the study. Mean time of onset of photorefractoriness in PR hens was 23.0 wk (range = 18 to 28 wk) after initiation of photostimulation. Egg production of PS hens was greater than that of PR hens after 20 wk of photostimulation, and PR hens molted a greater number of primary remiges than PS hens. Results indicated that 1) elevated plasma T4 may be involved in development of photorefractoriness in turkey hens, 2) increases in plasma T3 may be involved in gonadal regression and molting, and 3) elevated plasma prolactin was associated with persistence of photosensitivity.
在通过30周14小时光照：10小时黑暗诱导的产蛋周期中，每周测定血浆甲状腺素（T4）、三碘甲状腺原氨酸（T3）和催乳素的浓度。监测产蛋量、初级飞羽换羽情况和光不应性的发生。母鸡被分为两组；表现出光不应性（PR）的母鸡和保持光敏性（PS）的母鸡。相对于光刺激开始时间的每周血浆T4浓度在PR组和PS组之间没有差异；浓度在产蛋开始前达到峰值，在产蛋高峰期最低，并在光刺激的第6周和第30周之间增加。PR母鸡的血浆T4水平在光不应性开始前3周达到峰值。在光不应性开始时PR母鸡出现T3浓度升高之前，PS和PR母鸡的血浆T3浓度相似。PS和PR母鸡的血浆催乳素水平在光刺激后升高，PR母鸡下降得更快，并且在研究的最后20周内，PS母鸡的血浆催乳素水平通常高于PR母鸡。PR母鸡光不应性开始的平均时间是在光刺激开始后23.0周（范围=18至28周）。光刺激20周后，PS母鸡的产蛋量高于PR母鸡，并且PR母鸡换羽的初级飞羽数量比PS母鸡多。结果表明：1）血浆T4升高可能与火鸡母鸡光不应性的发展有关；2）血浆T3升高可能与性腺退化和换羽有关；3）血浆催乳素升高与光敏性的持续存在有关。
