产蛋期短期给予甲状腺素对火鸡产蛋和换羽的影响。

Effects of short-term thyroxine administration during the laying period on egg production and moulting by turkeys.

Lien R J, Siopes T D

Poultry Science Department, North Carolina State University, Raleigh 27695-7608.

Br Poult Sci. 1993 May;34(2):405-16. doi: 10.1080/00071669308417595.

Abstract

Effects of thyroxine (T4) administration on egg production, moulting and photorefractoriness in laying turkeys were determined. Thyroxine dosages of 0.075 to 2 mg/bird/d were injected IM for periods of either 2 or 3 weeks following 10 weeks of photostimulation. Control groups were administered saline vehicle. 2. Plasma T4 concentrations were increased in a dose dependent manner by T4 administration, while triiodothyronine (T3) was decreased. 3. Egg production and percentage of hens in production were transiently decreased in a dose dependent manner by T4 administration, but returned to levels similar to controls within 4 weeks of T4 treatment termination. Moulting was stimulated in a dose-dependent manner by T4 administration, but was similar to controls after T4 treatment termination. Only dosages of 2 mg/bird/d resulted in cessation of egg production and complete moulting. 4. Results indicate that although short term elevation of plasma T4 causes cessation of egg production and moulting these effects are transient and not indicative of photorefractoriness.

摘要

测定了甲状腺素（T4）给药对产蛋火鸡产蛋量、换羽及光不应性的影响。在光照刺激10周后，以0.075至2毫克/只/天的甲状腺素剂量进行肌肉注射，持续2或3周。对照组给予生理盐水载体。2. 甲状腺素给药使血浆T4浓度呈剂量依赖性增加，而三碘甲状腺原氨酸（T3）则降低。3. 甲状腺素给药使产蛋量和产蛋母鸡百分比呈剂量依赖性短暂下降，但在T4治疗终止后4周内恢复到与对照组相似的水平。甲状腺素给药以剂量依赖性方式刺激换羽，但在T4治疗终止后与对照组相似。仅2毫克/只/天的剂量导致产蛋停止和完全换羽。4. 结果表明，尽管血浆T4的短期升高会导致产蛋停止和换羽，但这些影响是短暂的，并不表明存在光不应性。