Technologies that increase the efficiency and sustainability of food animal production to provide meat for a growing population are necessary and must be used in a manner consistent with good veterinary practices, approved labeled use, and environmental stewardship. Compounds that bind to beta-adrenergic receptors (β-AR), termed beta-adrenergic receptor ligands (β-ligands), are one such technology and have been in use globally for many years. Though all β-ligands share some similarities in structure and function, the significance of their structural and pharmacological differences is sometimes overlooked. Structural variations in these molecules can affect absorption, distribution, metabolism, and excretion as well as cause substantial differences in biological and metabolic effects. Several β-ligands are available for use specifically in cattle production. Ractopamine and zilpaterol are beta-adrenergic agonists approved to increase weight gain, feed efficiency, and carcass leanness in cattle. They both bind to and activate β1- and β2-AR. Lubabegron is a newly developed selective beta-adrenergic modulator with unique structural and functional features. Lubabegron displays antagonistic behavior at the β1- and β2-AR but agonistic behavior at the β3-AR. Lubabegron is approved for use in cattle to reduce ammonia emissions per unit of live or carcass weight. Additionally, lubabegron can withstand prolonged use as the β3-AR lacks structural features needed for desensitization. Due to these unique features of lubabegron, this new β-ligand provides an additional option in cattle production. The individual properties of each β-ligand should be considered when making risk management decisions, as unique properties result in varying human food safety profiles that can determine appropriate safe β-ligand use.

中文翻译：

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牛生产中使用的β-配体的比较：结构、安全性和生物效应

提高食用动物生产效率和可持续性以向不断增长的人口提供肉类的技术是必要的，并且必须以符合良好兽医实践、批准的标签使用和环境管理的方式使用。与 β-肾上腺素能受体 (β-AR) 结合的化合物，称为 β-肾上腺素能受体配体 (β-ligands)，就是这样一种技术，已在全球范围内使用多年。尽管所有 β-配体在结构和功能上都有一些相似之处，但它们的结构和药理学差异的重要性有时会被忽视。这些分子的结构变化会影响吸收、分布、代谢和排泄，并导致生物和代谢效应的显着差异。有几种 β-配体可专门用于牛生产。莱克多巴胺和齐帕特罗是 β-肾上腺素能激动剂，被批准用于增加牛的体重增加、饲料效率和胴体瘦肉率。它们都结合并激活β1-和β2-AR。Lubabegron 是一种新开发的选择性β-肾上腺素能调节剂，具有独特的结构和功能特征。Lubabegron 在 β1-和 β2-AR 表现出拮抗行为，但在 β3-AR 表现出激动行为。Lubabegron 被批准用于牛，以减少每单位活体或胴体重量的氨排放量。此外，lubabegron 可以承受长时间使用，因为 β3-AR 缺乏脱敏所需的结构特征。由于 lubabegron 的这些独特特性，这种新的 β-配体为牛生产提供了额外的选择。