Redefining trace mineral nutrition in dairy cattle

微量矿物质是奶牛饮食中一个很小但至关重要的组成部分。尽管其重要性，我们的知识，微量矿物质的吸收和利用奶牛是有限的。微量矿物质的无机来源通常补充在奶牛的饮食中以优化性能，但它们的吸收受到胃肠道（GIT）内的拮抗相互作用的影响，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，并且这些微量矿物质的有机来源将被保护免受GIT中的大多数拮抗性相互作用，从而潜在地增加吸收的生物利用度并改善动物性能。尽管如此，关于有机微量矿物质作为奶牛饲料补充来源相比无机微量矿物质的优越性的结论性数据是不可用的。我们的多学科研究计划旨在调查奶牛饮食中补充微量矿物质的来源-有机或无机-对1）GIT吸收和矿物质的总体利用的影响; 2）瘤胃微生物组多样性和生物学; 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）生殖生物学和性能。有机和无机微量矿物质补充剂将在相同的纳入水平下进行比较，这将遵循国家研究理事会的建议。处理组将接受相同的饮食，除了补充钴、铜、锰、硒和锌的来源，其将是无机盐或有机蛋白质。实验将与圭尔夫大学和阿尔伯塔大学的研究小组合作进行。预计该项目的成果将导致对基本微量矿物质营养的更好理解，并将建立有机来源完全替代无机微量矿物质作为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.