Effects of methionine deficiencies on plasma levels of thyroid hormones, insulin-like growth factors-I and -II, liver and body weights, and feed intake in growing chickens
Effects of methionine deficiencies on plasma levels of thyroid hormones, insulin-like growth factors-I and -II, liver and body weights, and feed intake in growing chickens
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DOI：
10.1093/ps/82.12.1932
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发表时间：
2003-12-01
期刊：
影响因子：
4.4
通讯作者：
Alster, FA
中科院分区：
文献类型：
--
作者：
Carew, LB;McMurtry, JP;Alster, FA
我们之前表明，日粮中 0.25% 的 Met 缺乏会导致肉鸡血浆三碘甲状腺原氨酸 (T-3) 升高。在本研究中，测量了饲喂 3 种总蛋氨酸水平不足的小鸡的甲状腺激素以及胰岛素样生长因子 (IGF)-I 和 -II 的血浆水平。 8至22日龄的雄性肉鸡饲喂对照日粮（0.5%）和缺乏蛋氨酸日粮（0.4%、0.3%和0.2%）。另外几组对照雏鸡与缺乏蛋氨酸的雏鸡配对喂养。接受 0.4% 蛋氨酸的雏鸡的采食量增加了 10%，但体重没有显着变化。 0.3% 和 0.2% 的更严重的 Met 缺乏导致采食量和体重增加逐渐减少。然而，相应的配对喂养对照雏鸡明显更重。这些变化表明 0.3% 和 0.2% Met 的代谢过程比 0.4% Met 的变化更显着。饲喂 0.3% 和 0.2% 蛋氨酸的雏鸡肝脏重量较重，但饲喂 0.4% 蛋氨酸的雏鸡则不然。与自由饲喂对照相比，所有缺陷雏鸡的血浆 T-3 均较高，仅在 0.3% Met 时才显着。然而，与配对喂养对照相比，0.3% 和 0.2% Met 的血浆 T-3 显着升高。所有缺陷组的血浆甲状腺素 (T-4) 均较低，只有 0.2% Met 时才显着，而缺陷雏鸡与其配对喂养对照之间没有出现显着差异。血浆 IGF-I 水平没有显着差异，但缺陷雏鸡的血浆 IGF-I 水平始终较低，值得进一步研究。与配对饲喂对照相比，饲喂 0.2% Met 的雏鸡血浆 IGF-II 显着减少，表明 Met 缺乏会干扰 IGF-II 代谢。我们得出的结论是，饮食中 Met 的缺乏会改变血浆 T-3 和 IGF-II 水平，但效果取决于缺乏的程度。
We showed previously that Met deficiency at 0.25% of the diet causes elevations in plasma triiodothyronine (T-3) in broilers. In the present study, plasma levels of thyroid hormones as well as insulin-like growth factors (IGF)-I and -II were measured in chicks fed 3 deficient levels of total Met. Control (0.5%) and Met-deficient diets (0.4, 0.3, and 0.2%) were fed to male broilers from 8 to 22 d of age. Additional groups of control chicks were pair-fed with the Met-deficient ones. Chicks receiving 0.4% Met increased feed intake by 10% with no significant change, in body weight. The more severe Met deficiencies of 0.3 and 0.2% caused graded reductions in feed intake and weight gain. However, corresponding pair-fed control chicks were significantly heavier. These changes suggest more marked alterations in metabolic processes with 0.3 and 0.2% Met than with 0.4% Met. Liver weights were heavier in chicks fed 0.3 and 0.2% Met but not 0.4%. Plasma T-3 was higher in all deficient chicks compared with the free-fed control, which was significant only with 0.3% Met. However, with 0.3 and 0.2% Met, plasma T-3 was significantly elevated compared to pair-fed controls. Plasma thyroxine (T-4) was lower in all deficient groups, which was significant only with 0.2% Met, whereas no significant differences occurred between deficient chicks and their pair-fed controls. Plasma IGF-I levels were not significantly different, but they were consistently lower in deficient chicks and deserve further study. Plasma IGF-II was significantly less in chicks fed 0.2% Met compared to pair-fed controls suggesting that Met deficiency interferes with IGF-II metabolism. We concluded that a deficit of dietary Met altered plasma T-3 and IGF-II levels, but the effect was dependent on the degree of deficiency.