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1.
甲状腺激素在动物生长中是必需的。甲状腺激素有甲状腺素(T_4)和三碘甲状腺胺酸(T_3)。这两种激素都由甲状腺分泌合成,而 T_4脱碘后可转化为活性强的 T_3,其作用机制还不太清楚。甲状腺对动物机体代谢有重要调节作用。但这种机能随动物年龄、季节、环境温度、饲料等的变化而变化。由于品种、个体之间都有差异,因此,其代谢也有差异。自1994年 Turuer 等人报道碘酪蛋白(含碘6%)具有促进甲状腺激素分泌的作用以来,人们对家畜应用碘酪蛋白的研究较多,而且取得了不少效果。特别在蛋鸡、乳牛等方面效果更为明显。但是,由于碘酪蛋白与甲状腺激素一样都具有同化和异化作 相似文献
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前言甲状腺激素为生长所必需。甲状腺激素包括甲状腺素(T_4)和三碘甲腺原氨酸(T_3)。它们均由甲状腺合成,因此,甲状腺对调节代谢具有重要作用。 Turner等(1944)发现碘结合酪蛋白(即碘酪蛋白,约含碘6％)具有甲状腺激素活性。此后,研究人员相继进行了碘酪蛋白用于畜牧生产的研究,迄今已取得了相当好的成果,在提高产蛋量、泌乳量方面效果尤为显著。 相似文献
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影响家兔生产的因素很多,如品种、饲料营养、饲养管理、疾病防治等,其中饲料营养是影响家兔生产的最重要的物质基础。科学合理地利用饲料。是提高家兔生产效益的根本保证。碘是动物生长发育和生产过程中所必需的微量元素,虽然需要量很小,但对机体的作用是巨大的。其主要功能是参与甲状腺激素的合成,并通过甲状腺激素发挥多方面的生理作用。家兔缺碘时,会导致生长发育受阻,毛皮质量下降,新陈代谢紊乱等症状,从而影响动物生产性能。家兔摄碘过多会发生中毒症,影响生长发育。为了更好地在家兔生产上发挥碘对动物的营养作用,笔者就微量元素碘对家兔的营养作用进行了综述。 相似文献
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1944年Turner等人报道碘酪蛋白(含碘6％)具有促进甲状腺激素分泌的作用以来,人们对家畜应用碘酪蛋白的研究增多了,取得了不少效果。特别在蛋鸡、乳牛等方面的效果更为明显。但是,由于碘酪蛋白与甲状腺激素一样都具有同化和异化作用,而效果不够稳定。长期使用,会引起体重下降、体组织成份耗损等。现在,美国、加拿大等国家开始应用。日本原来有较多工厂生产碘酪蛋白,主要用于治疗人的有关疾病,家畜也使用。但是,合成甲状腺素问世后,临床上多使用甲状腺素,在畜禽饲料中很少使用碘酪蛋白。随着畜牧生产方式的 相似文献
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《江西饲料》2021,(2):49-50
恒温动物维持高而恒定的体温对于其生存至关重要,而体温的维持具有较高的能量代价,体温调节是经典的生理学问题.甲状腺激素是由甲状腺细胞分泌,包括甲状腺素(T4)和三碘甲状腺原氨素(T3),T4经过碘甲腺原氨酸脱碘酶Ⅱ(DIO2)脱碘后生成T3而起作用,甲状腺激素能够提高能量代谢、促进生长发育并提高神经系统的兴奋性.甲状腺激素代谢紊乱会发展为甲亢(甲状腺机能亢进)或甲减(甲状腺机能减弱)疾病,遗传、药物、长期应激等是形成甲亢的主要因素,发病率较高且难以治疗.关于甲状腺激素调节代谢产热的作用机制,已有研究认为主要通过中枢调控通路或外周直接作用于器官调节细胞的代谢过程,前期研究已发现肠道微生物能够调节宿主动物的能量代谢.甲状腺功能紊乱是否与肠道菌群失衡有关从而导致能量代谢和产热的变化?对于这一问题的解释,能够揭示恒温动物的体温调节机制,并为认识甲状腺疾病的成因和治疗方法提供科学依据. 相似文献
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碘是牛羊等动物合成甲状腺激素不可少的成分，甲状腺激素对机体的生物学作用极为广泛，牛羊等动物一旦碘缺乏就会引起碘缺乏症。该病的临诊特征是甲状腺增生肿大，生长发育受阻和繁殖成活率下降等。严重的造成死亡。目前，我省各地普遍缺碘，人以碘盐补充，而家畜没有投入碘盐，所以容易发生缺碘症。就我们掌握的缺碘情况，提醒广大养殖户。要做好补碘工作。 相似文献
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碘缺乏对家畜生产性能的影响 总被引：4，自引：0，他引：4
李自新 《青海畜牧兽医杂志》1996,26(1):40-42
碘缺乏对家畜生产性能的影响李自新（青海畜牧兽医学院，西宁，８１０００３）碘是家畜必需微量元素之一，其主要功能是参与甲状腺激素合成，并通过甲状腺激素发挥多方面的生理作用。家畜缺碘时，由于甲状腺激素的机能障碍而导致生长发育受阻，繁殖机能及新陈代谢紊乱，从... 相似文献
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碘是动物健康生长和生产所必需的微量元素之一.碘的主要生理机能是参与甲状腺激素(T_3、Y_4)的合成,以甲状腺激素这一活性形式参与动物体内几乎所有物质的代谢,从而影响动物的生长、发育和繁殖.我们通过饲养试验测定了玉米-豆粕型肉鸡日粮中碘的适宜添加量. 相似文献
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Lisa G Barber 《Veterinary Clinics of North America: Small Animal Practice》2007,37(4):755-73, vii
The clinical presentation and biologic behavior of thyroid tumors vary widely among dogs, cats, and human beings. Although thyroid tumors in dogs are rare, they are most likely to be malignant. Clinical signs are usually the result of impingement on surrounding structures, and clinical hyperthyroidism is rare. In contrast, hyperthyroidism resulting from benign thyroid proliferation is relatively common among older cats. Malignant tumors are extremely uncommon but have high metastatic potential. Irrespective of the tumor's ability to produce functional thyroid hormone, scintigraphy is often helpful in the diagnosis and staging of thyroid tumors in all three species. Treatment with surgery is a reasonable treatment option for noninvasive tumors. Iodine 131 is a well-established treatment for thyroid nodules in cats, but its effectiveness in dogs is controversial. In dogs, external beam radiation therapy has produced more consistent results in affording local tumor control when surgery is not possible. 相似文献
12.
Clinico-chemical and radiometric methods, common in routine diagnosis in human medicine for in-vitro assessment of thyroid function, were tested for their applicability to calf. The assessment of protein-fixed iodine and of iodine extractable from stock, the thyroxine test, the tri-iodothyronine test, the tri-iodothyronine radio-immuno assay, and the effective thyroxine ratio test, basically, were applicable to diagnosis of thyroid function in calf. The thyrotrophin releasing hormone test, in conjunction with efforts to determine peripheral thyroid gland hormone concentration (in particular tri-iodothyronine), was also applicable to calf, although thyroid stimulation hormone with radio-immuno assay, another procedure in human medicine (specificity of thyroid stimulation hormone antibody), proved unsuitable for the determination of bovine thyroid stimulation hormone. 相似文献
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The effects of different iodide availabilities on thyroid function during development in Japanese quail 总被引：1，自引：0，他引：1
Japanese quail (Coturnix japonica) were used to study the effects of different egg iodide (I) availabilities on thyroid function during development. Low (less than 50 micrograms 1/kg feed in the maternal diet) and high (1200 micrograms 1/kg feed) I availability were compared to control levels (800 micrograms 1/kg feed), a standard supplementation for game bird feed. We measured thyroid gland content of I, triiodothyronine (T3) and thyroxine (T4), plasma concentrations of T3 and T4, hepatic 5' monodeiodinase (5'-D) activity, and the response of the thyroid gland to thyrotrophin (TSH) stimulation. Embryos, on day 14 of the 16.5-17 day incubation period, and 1-day chicks were used for most studies but thyroid gland hormone content and plasma hormone concentrations were determined for more stages. With high I, thyroidal I content was elevated but thyroidal T4 and T3 were not different from controls. Plasma T3 and T4, the thyroid gland response to TSH stimulation, and hepatic 5'-D activity did not differ between control and high I. Reduced body weight occurred with high I. In general, thyroid gland weight was not altered, but some high I birds exhibited thyroid hypertrophy and altered thyroid gland function. With low I availability, thyroid gland contents of I and T4 were reduced but thyroidal T3 content was maintained. The thyroid gland response to TSH stimulation, plasma thyroid hormone concentrations, and the developmental patterns of plasma thyroid hormones, hepatic 5'-D activity, body weight and thyroid weight were not different between control and low I groups. Developing Japanese quail exhibit excellent ability to adjust thyroid function over a wide range of I availabilities. Regulation appears to occur at the level of thyroid hormone synthesis in the thyroid gland, which allows most aspects of thyroid dynamics to remain unchanged in the maintenance of circulating thyroid hormone concentrations. 相似文献
14.
K M Beale 《Veterinary Clinics of North America: Small Animal Practice》1990,20(6):1429-1441
Hypothyroidism is a common endocrinopathy in dogs. There are a wide variety of diagnostic tests to evaluate thyroid function. The measurement of basal thyroid hormone concentrations is used widely as an indicator of thyroid function; however, there are many factors that may affect basal hormone concentrations. The thyrotropic stimulation test is not affected by many of these factors, and often it is preferred for this reason. Current diagnostic procedures for evaluating thyroid function for the veterinary practitioner are reviewed. 相似文献
15.
Robert W. Kramer DVM G. Sylvester Price DVM Gary J. Spodnick DVM 《Veterinary radiology & ultrasound》1994,35(2):132-136
Hypothyroidism was diagnosed in a dog which had undergone unilateral thyroid lobectomy and external beam irradiation (48 Gy in 3 Gy fractions) for a functional cystic thyroid adenocarcinoma. Hypothyroidism became biochemically apparent within 4 months of completion of radiation therapy, and clinically apparent within 7 months. Clinical signs resolved after thyroid hormone supplementation. The potential for alterations in thyroid function should be considered in any animal undergoing radiation therapy in which the thyroid gland is included in the radiation field. This potential may be greater if surgery and radiation are combined. 相似文献
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Studies were made with a total of 272 fattening pigs. Iodine deficiency both in rations of soya bean meal and rape seed meal increased the weight of the thyroid gland and the height of the epithelium cells and significantly reduced the T4 and T3 level in the serum. Iodine supplements to the rape seed meal rations distinctly diminished the goitrogenic effect, did not, however, cancel it out. Stage of goiter and depression of consumption were--different shown by the T3 and T4 level in the serum. Highly significant relations were calculated between live weight gain, weight and the height of the epithelium cells on the one hand and the T4 level in the serum on the other. Iodine supplementations of rations without thyrostatic components should amount to greater than or equal to 0.1 mg/kg. Iodine supplementations of 0.5 mg/kg feed are at present recommended to rations with rape seed meal quotas of less than 8%. 相似文献
17.
Hypothyroidism and concurrent sex hormone imbalance associated with alopecia was diagnosed in a 5 year-old entire male Miniature Poodle. The dog had a 3-year history of alopecia, seborrhoea and recurrent superficial pyoderma. Abnormal thyrotropin releasing hormone stimulation test results supported a diagnosis of hypothyroidism. Partial hair regrowth occurred after interstitial cell tumours, which were present in both testicles, were removed by castration. Complete hair regrowth, however, occurred only after thyroid hormone supplementation. This case highlighted difficulties which may be encountered when interpreting serum hormone concentrations and endocrine function tests. 相似文献
18.
Porter TE 《Domestic animal endocrinology》2005,29(1):52-62
Anterior pituitary somatotroph differentiation occurs during chick embryonic and rat fetal development. A number of findings support the hypothesis that differentiation of these growth hormone (GH) producing cells in the chick and the rat is regulated by adrenal glucocorticoids and thyroid hormones. Somatotroph differentiation can be induced in cultures of chick embryonic and rat fetal pituitary cells with adrenal glucocorticoids and this effect can be modulated by concomitant treatment with thyroid hormones. Plasma levels of thyroid hormones, corticosterone and adrenocorticotropic hormone increase during development, consistent with the ontogeny of somatotrophs. Treatment of chick embryos or rat fetuses with glucocorticoids in vivo induces premature somatotroph differentiation, indicating that the adrenal gland, and ultimately anterior pituitary corticotrophs, may function to regulate pituitary GH cell differentiation during development. Administration of thyroid hormones in vivo also increases somatotrophs prematurely, and administration of the thyroid hormone synthesis inhibitor methimazole inhibits somatotroph differentiation in vivo, suggesting that endogenous thyroid hormone synthesis contributes to normal somatotroph differentiation. Our working model for the regulation of somatotroph differentiation during normal development includes modulation by elements of the hypothalamo-pituitary-adrenal and hypothalamo-pituitary-thyroid axes. Additional research is reviewed defining the mechanism of action for these peripheral hormones in induction of pituitary GH gene expression during development. 相似文献
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AIM: To determine the effect of iodine supplementation on milk production and iodine concentrations in milk for pasture-fed, seasonally calving dairy cows. METHODS: The study was run over two consecutive seasons on the same dairy farm. In Trial One, 294 Friesian dairy cows were either untreated or injected intramuscularly three times with iodised oil (2,370 mg iodine/dose) at the start of lactation (Day 1) and at about 100-day intervals thereafter. Iodine concentrations in milk were determined prior to each injection on Days 1, 98 and 210, and milk, fat and protein yields measured on Days 43, 98, 176 and 238. In Trial Two, 234 Friesian dairy cows were either untreated or injected intramuscularly with iodised oil (2,370 mg iodine/dose) in early lactation (Day 1) and 99 days later. Iodine concentrations in milk were determined prior to treatment on Days 1, 55 and 161. Serum thyroxine (T4) and triiodothyronine (T3) concentrations were determined in the latter two samples and milk, protein and fat yields were determined on Days 25, 119, 182 and 221. In both trials, pasture was sampled at 1- or 3-monthly intervals and iodine concentrations in herbage measured. RESULTS: Iodine concentrations in pasture averaged 0.24 mg/kg dry matter (DM) in both seasons and varied little over the experimental period. Iodine concentrations in milk from unsupplemented cows were <20 microg/L in both trials. Three iodine injections at about 100-day intervals increased iodine concentrations in milk to 58 microg/L for at least 98 days after each treatment. Two iodine injections at about 100-day intervals raised milk iodine concentrations to 160 microg/L and 211 microg/L at least 55 days after each treatment, but had no effect on serum thyroid hormone concentrations. Iodine supplementation had no significant effect on milk, milkfat or milk protein yield. CONCLUSIONS: Pastures in New Zealand that contained 0.24 mg iodine/kg DM appeared to provide an adequate iodine intake for dairy cows. Intramuscular injections of iodine resulted in significant increases in iodine concentrations in milk. CLINICAL SIGNIFICANCE: Increasing iodine concentrations in milk via intramuscular injection of iodine could provide a method for significantly increasing iodine intakes of humans, in particular, children. 相似文献
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Objective : To assess the value of thyroid scintigraphy to determine thyroid status in dogs with hypothyroidism and various non‐thyroidal illnesses. Methods : Thyroid hormone concentrations were measured and quantitative thyroid scintigraphy performed in 21 dogs with clinical and/or clinicopathological features consistent with hypothyroidism. Results : In 14 dogs with technetium thyroidal uptake values consistent with euthyroidism, further investigations supported non‐thyroidal illness. In five dogs with technetium thyroidal uptake values within the hypothyroid range, primary hypothyroidism was confirmed as the only disease in four. The remaining dog had pituitary‐dependent hyperadrenocorticism. Two dogs had technetium thyroidal uptake values in the non‐diagnostic range. One dog had iodothyronine concentrations indicative of euthyroidism. In the other, a dog receiving glucocorticoid therapy, all iodothyronine concentrations were decreased. Markedly asymmetric technetium thyroidal uptake was present in two dogs. All iodothyronine concentrations were within reference interval but canine thyroid stimulating hormone concentration was elevated in one. Non‐thyroidal illness was identified in both cases. Clinical Significance : In dogs, technetium thyroidal uptake is a useful test to determine thyroid function. However, values may be non‐diagnostic, asymmetric uptake can occur and excess glucocorticoids may variably suppress technetium thyroidal uptake and/or thyroid hormone concentrations. Further studies are necessary to evaluate quantitative thyroid scintigraphy as a gold standard method for determining canine thyroid function. 相似文献