Redefining trace mineral nutrition in dairy cattle

微量矿物质是奶牛饮食中一种很小但很关键的成分。尽管它很重要，但我们对奶牛对微量矿物质的吸收和利用的了解是有限的。为了优化奶牛的生产性能，经常在日粮中添加微量元素的无机来源，但它们的吸收受到胃肠道(GIT)内拮抗作用的影响，从而降低了它们的生物利用度。动物饲料公司已经开发出将无机元素与有机分子复合的技术，这些微量矿物质的有机来源将受到保护，不受GIT中大多数拮抗作用的影响，从而潜在地提高吸收的生物利用度，并改善动物的性能。尽管如此，关于有机与无机微量矿物质作为奶牛饲喂补充来源的优越性的确凿数据尚不存在。我们的多学科研究计划旨在调查奶牛日粮中添加微量矿物质的来源-有机或无机-对1)Git吸收和矿物质的综合利用；2)瘤胃微生物群多样性和生物学；3)饲料效率、代谢和产奶量；4)免疫细胞功能、氧化平衡和健康；以及5)繁殖生物学和生产性能的影响。有机和无机微量矿物质补充剂将按照国家研究委员会的建议，在相同的包含率水平下进行比较。治疗组将接受相同的饮食，除了补充钴、铜、锰、硒和锌的来源，这些来源将是无机盐或有机蛋白质。实验将与圭尔夫大学和艾伯塔大学的研究小组合作进行。预计项目成果将导致对基本微量矿物质营养的更好理解，并将确立有机来源完全替代无机微量矿物质，这是一个有利可图的管理决策。

Trace minerals represent a small but crucial component of a dairy cow's diet. Despite its importance, our knowledge regarding trace mineral absorption and utilization in dairy cattle is limited. Inorganic sources of trace minerals are often supplemented in diets of dairy cattle to optimize performance, but their absorption is compromised by antagonistic interactions within the gastrointestinal tract (GIT) that reduce their bioavailability. Animal feed companies have developed technologies to complex inorganic elements with organic molecules, and these organic sources of trace minerals would be protected from most antagonistic interactions in the GIT, thus potentially increasing bioavailability for absorption and improving animal performance. Nonetheless, conclusive data regarding the superiority of organic compared to inorganic trace minerals as supplemental sources for dairy cattle feeding is not available. Our multidisciplinary research proposal aims to investigate the impact of the source of supplemental trace minerals - organic or inorganic in diets of dairy cows on 1) GIT absorption and overall utilization of minerals; 2) rumen microbiome diversity and biology; 3) feed efficiency, metabolism, and milk production; 4) immune cell function, oxidative balance and health; and 5) reproductive biology and performance. Organic and inorganic trace mineral supplements will be compared at the same inclusion levels, which will follow the recommendation of the National Research Council. Treatments groups will receive the same diet, except for the source of supplemental cobalt, copper, manganese, selenium, and zinc, which will be either inorganic salts or organic proteinates. Experiments will be conducted in collaboration with research groups at the University of Guelph and the University of Alberta. It is anticipated that the project outcomes will lead to an improved understanding of basic trace mineral nutrition, and will establish complete substitution of inorganic trace minerals by organic sources as a profitable managerial decision.