Agriculture et agroalimentaire Canada, Centre de recherche et développement de Sherbrooke, 2000 College, Sherbrooke J1M 0C8, Québec, Canada.
Université Clermont Auvergne, INRAE, VetAgro Sup, UMR Herbivores, F-63122 Saint-Genès-Champanelle, France.
Methods. 2021 Feb;186:52-58. doi: 10.1016/j.ymeth.2020.05.021. Epub 2020 May 30.
Clinical symptoms of B vitamin deficiency are rarely observed in ruminants because these vitamins are synthesized by the rumen microbiota. However, over the last decades, numerous reports of beneficial effects on production and metabolic efficiency of dairy cows have been published supporting that, under some conditions, B vitamin subclinical deficiency is present in these animals. Due to their roles as coenzymes or cofactors in major metabolic pathways, an adequate supply in B vitamins is critical to optimize metabolic efficiency. Nowadays, taking into account the growing interest for the Smart Farming concept, fulfilling ruminant requirements for B vitamins according to their physiological stage under different feeding management cannot be neglected. In dairy cows, B vitamin supply is greatly dependent of the activity of the ruminal microbiota. Indeed, the amount of vitamins reaching the small intestine is dependent of the utilization of the vitamins provided by the diet and their synthesis by the microorganisms present in the rumen. The two major challenges faced to determine B vitamin status of ruminants are the difficulty to estimate B vitamin supply due to the lack of knowledge on factors driving the fate of B vitamins in the digestive tract, especially in the rumen, and the choice and thresholds of biomarkers reflecting adequately the animal status. The present paper aims to present the actual state of knowledge on the methodological approaches used to estimate B vitamin supply and status of ruminant and to point out future research orientations.
反刍动物很少出现维生素 B 缺乏的临床症状，因为这些维生素是由瘤胃微生物合成的。然而，在过去的几十年里，有许多关于奶牛生产和代谢效率有益影响的报道，支持在某些条件下，这些动物存在维生素 B 亚临床缺乏。由于它们作为辅酶或辅助因子在主要代谢途径中的作用，充足的维生素 B 供应对于优化代谢效率至关重要。如今，考虑到对智能农业概念的兴趣日益浓厚，根据不同的饲养管理条件下反刍动物的生理阶段，满足其对维生素 B 的需求不容忽视。在奶牛中，维生素 B 的供应很大程度上依赖于瘤胃微生物的活性。事实上，到达小肠的维生素数量取决于饮食中提供的维生素的利用情况以及瘤胃中存在的微生物对其的合成情况。确定反刍动物维生素 B 状况面临的两个主要挑战是由于缺乏对影响消化道（特别是瘤胃）中维生素命运的因素的了解，难以估计维生素 B 的供应情况，以及选择和确定能够充分反映动物状况的生物标志物的阈值。本文旨在介绍目前用于估计反刍动物维生素 B 供应和状况的方法学方法的知识现状，并指出未来的研究方向。
