Wang J S, Rogers S R, Pesti G M
Department of Poultry Science, University of Georgia, Athens 30602.
Poult Sci. 1987 Sep;66(9):1500-7. doi: 10.3382/ps.0661500.
Studies were conducted to determine if the deleterious affects on chick growth of the primary antagonism between methionine and copper involves the homocysteine moiety or labile methyl group of methionine. A .1% choline supplement resulted in performance response similar to that of a .2% L-methionine supplement in the absence but not in the presence of 500 mg/kg copper from cupric sulfate. Similar results were observed when the levels of methionine and choline were doubled. Sulfate, with or without choline, had little effect in the presence of cupric sulfate. When cupric acetate was used instead of cupric sulfate, a small but nearly significant (P = .08) response to potassium sulfate was observed. Maximum performance with .29% supplemental methionine and 188 mg/kg Cu was predicted from a response surface analysis. The methionine requirement was increased by feeding copper. However, the increase in methionine requirement was accompanied by an improvement in growth rate and feed efficiency. This may explain why levels used of methionine and total sulfur-containing amino acids appear to be higher under field conditions (with pharmacological levels of copper) than in laboratory conditions (without pharmacological levels of copper). The primary antagonism between methionine and copper involves the homocysteine moiety, not the labile methyl groups.
开展了多项研究，以确定蛋氨酸与铜之间的主要拮抗作用对雏鸡生长的有害影响是否涉及蛋氨酸的同型半胱氨酸部分或不稳定甲基。在不存在硫酸铜（500毫克/千克铜）的情况下，补充0.1%的胆碱所产生的性能反应与补充0.2%的L-蛋氨酸相似，但在存在硫酸铜的情况下则不然。当蛋氨酸和胆碱的水平加倍时，观察到了类似的结果。在存在硫酸铜的情况下，无论有无胆碱，硫酸盐几乎没有影响。当使用醋酸铜代替硫酸铜时，观察到对硫酸钾有一个小但接近显著水平（P = 0.08）的反应。通过响应面分析预测，补充0.29%的蛋氨酸和188毫克/千克的铜时性能最佳。添加铜会增加蛋氨酸的需求量。然而，蛋氨酸需求量的增加伴随着生长速度和饲料效率的提高。这或许可以解释为什么在田间条件下（使用药理水平的铜）蛋氨酸和总含硫氨基酸的使用量似乎比在实验室条件下（不使用药理水平的铜）更高。蛋氨酸与铜之间的主要拮抗作用涉及同型半胱氨酸部分，而非不稳定甲基。
