Beck Matthew R, Gregorini Pablo
Faculty of Agriculture and Life Sciences, Lincoln University, Lincoln, New Zealand.
Front Vet Sci. 2020 Apr 15;7:191. doi: 10.3389/fvets.2020.00191. eCollection 2020.
Ruminants evolved in diverse landscapes of which they utilized, by choice, a diverse arrangement of plants (grasses, forbs, and trees) for food. These plants provide them with both primary (carbohydrates, protein, etc.) and secondary (phenolics, terpenes, etc.) compounds (PPC and PSC, respectively). As no one plant could possibly constitute a "balanced-diet," ruminants mix diets so that they can exploit arrangements of PPC to meet their individual requirements. Diet mixing also allows for ruminants to ingest PSC at levels, acquiring their benefits such as antioxidants and reduced gastrointestinal parasites, without overstepping thresholds of toxicity. Meeting dietary requirements is assumed to provide satisfaction through achieving positive internal status and comfort, thereby a sense of hedonic (happiness through pleasure) well-being. Furthermore, choice including dietary choice is a factor influencing well-being of ruminants in a manner akin to that in humans. Choice may facilitate eudaimonic (happiness through pursuit of purpose) well-being in livestock. Nutritional status plays an integral role in oxidative stress, which is linked with illness. Several diseases in livestock have been directly linked to oxidative stress. Mastitis, metritis, hypocalcaemia, and retained placenta occur in animals transitioning from dry to lactating and have been linked to oxidative stress and such a stress has likewise been linked to diseases that occur in growing livestock as well, such as bovine respiratory disease. The link between physiological stress and oxidative stress is not well-defined in livestock but is evident in humans. As dietary diversity allows animals to select more adequately balanced diets (improved nutrition), take advantage of PSC (natural antioxidants), and allows for choice (improved animal well-being) there is a strong possibility for ruminants to improve their oxidative status and thus health, well-being, and therefor production. The purposes of this review are to first, provide an introduction to oxidative and physiological stress, and nutritional status as effected by dietary diversity, with special attention to providing support and on answering the "how." Second, to provide evidence of how these stresses are connected and influence each other, and finally discuss how dietary diversity provides a beneficial link to all three and enhances both eudaimonic and hedonic well-being.
反刍动物在多样的环境中进化，它们会自主选择食用多种植物（草、阔叶植物和树木）。这些植物为它们提供了主要化合物（碳水化合物、蛋白质等）和次生化合物（酚类、萜类等）（分别为PPC和PSC）。由于没有一种植物能构成“均衡饮食”，反刍动物会混合食物，以便利用PPC的组合来满足它们各自的需求。食物混合还使反刍动物能够摄入一定水平的PSC，在不超过毒性阈值的情况下获得其益处，如抗氧化剂和减少胃肠道寄生虫。满足饮食需求被认为通过实现积极的内部状态和舒适感，从而带来享乐主义（通过愉悦获得幸福）的幸福感。此外，包括饮食选择在内的选择是以类似于人类的方式影响反刍动物幸福感的一个因素。选择可能有助于家畜实现幸福主义（通过追求目标获得幸福）的幸福感。营养状况在氧化应激中起着不可或缺的作用，而氧化应激与疾病有关。家畜中的几种疾病已直接与氧化应激相关联。乳腺炎、子宫炎、低钙血症和胎盘滞留发生在从干奶期过渡到泌乳期的动物身上，并与氧化应激有关，这种应激同样也与生长家畜中发生的疾病有关，如牛呼吸道疾病。生理应激和氧化应激之间的联系在家畜中尚未明确界定，但在人类中很明显。由于饮食多样性使动物能够选择更充分均衡的饮食（改善营养），利用PSC（天然抗氧化剂），并允许有选择（改善动物幸福感），反刍动物极有可能改善其氧化状态，从而改善健康、幸福感，并因此提高产量。本综述的目的首先是介绍氧化应激和生理应激，以及饮食多样性对营养状况的影响，特别关注提供支持并回答“如何”的问题。其次，提供这些应激如何相互关联和相互影响的证据，最后讨论饮食多样性如何为这三者提供有益联系并增强幸福主义和享乐主义的幸福感。
