Published data on the beneficial effect of short-term administration of thyroxine (T4) in broiler breeder hens to reduce the ascites incidence in their progeny chicks raises the question as to what extent might the long-term maternal administration of T4 affect the blood hematological and biochemical attributes in breeder hens. A total of 70 broiler breeder hens (47-wk-old) were randomly allotted to control or thyroxine treated (T4) groups. Pure T4 (0.3 mg/bird per day) was orally administered to T4 birds for 14 successive weeks, whereas the control group received the drinking water only. Blood samples were obtained from the brachial vein prior to the initiation of the trial as well as weeks 50, 53, 55, 57, 59, and 61 of age. Body weight was decreased but egg production was not affected by T4 treatment. Plasma concentration of T4, but not triiodothyronine (T3), was increased in T4-treated hens (P < 0.05). The total number of leukocytes and erythrocytes were also higher in T4 birds. A significant effect of time was observed for erythrocyte number and plasma cholesterol concentration (P < 0.05). The long-term administration of T4 did not affect the concentrations of serum calcium and plasma total protein, albumin, globulin, cholesterol, triglyceride, high density lipoprotein, low density lipoprotein, very low density lipoprotein, alanine amino transferase, and aspartate amino transferase (P > 0.05). However, serum concentrations of phosphorus, glucose, and alkaline phosphatase were higher in T4 hens as compared to their control counterparts. In spite of differences in circulatory concentrations of a number of traits between the experimental groups, the recorded values were within their reference ranges. Therefore, the administration of T4 for an extended period of time had no apparent adverse effect on the clinical profile in subjected hens, which may practically support the implementation of this preventative treatment as an approach to decrease the ascites incidence; however, a lower incidence rate in the progeny chicks produced from hens receiving T4 for long-term periods of time remains to be elucidated.

中文翻译：

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甲状腺素的长期口服给药：对肉种鸡血液血液学和生化特征的影响。

已发表的关于在肉种鸡中短期施用甲状腺素 (T4) 以降低其后代雏鸡腹水发生率的有益效果的数据提出了一个问题，即母体长期施用 T4 可能在多大程度上影响血液血液学和种鸡的生化特性。总共 70 只肉种鸡（47 周龄）被随机分配到对照组或甲状腺素治疗（T4）组。连续 14 周向 T4 鸡只口服纯 T4（每天 0.3 毫克/只），而对照组只接受饮用水。在试验开始前以及第 50、53、55、57、59 和 61 周时从肱静脉采集血样。体重下降但产蛋量不受 T4 处理的影响。T4的血浆浓度，但 T4 处理的母鸡中三碘甲状腺原氨酸 (T3) 增加 (P < 0.05)。T4 鸡的白细胞和红细胞总数也较高。观察到红细胞数量和血浆胆固醇浓度对时间有显着影响（P < 0.05）。长期服用T4不影响血清钙和血浆总蛋白、白蛋白、球蛋白、胆固醇、甘油三酯、高密度脂蛋白、低密度脂蛋白、极低密度脂蛋白、丙氨酸氨基转移酶和天冬氨酸氨基转移酶的浓度。 P > 0.05)。然而，与对照组相比，T4 母鸡的血清磷、葡萄糖和碱性磷酸酶浓度较高。尽管实验组之间许多性状的循环浓度存在差异，记录值在其参考范围内。因此，长时间给予 T4 对受试母鸡的临床表现没有明显的不利影响，这实际上可能支持实施这种预防性治疗作为降低腹水发生率的方法；然而，长期接受 T4 的母鸡所产后代雏鸡的较低发病率仍有待阐明。