Food for Health Ireland, UCD Institute of Food and Health, University College Dublin, Belfield, Dublin 4, Ireland.
J Sci Food Agric. 2018 Aug;98(11):4177-4183. doi: 10.1002/jsfa.8939. Epub 2018 Mar 12.
Effective micronutrient supplementation strategies are critical to ensure optimal health and productivity in livestock. The objective of this study was to develop a copper and vitamin (multimicronutrient) delivery system based on chitosan gel beads, and test its suitability, in vitro, for use as a cattle feed additive.
Chitosan was chelated with copper sulfate to produce millimetre-scale gel matrices (∼2 mm). The copper content was significantly increased (from 61 to 95 mg g by adjusting pH to alkaline conditions post bead formation. The beads could subsequently be loaded with the model vitamin riboflavin to levels as high as 324 µg g beads. Restricted rehydration of the dried gel matrices in simulated rumen fluid led to a sustained release of riboflavin with no copper released in these neutral conditions for up to 24 h, demonstrating copper rumen bypass. Moreover, sustained release of the mineral was observed in abomasal conditions of pH 2 over a 3 h period.
The matrices showed rumen bypass for copper yet supplied nutritionally relevant levels of the free mineral in abomasal conditions, as required for effective supplementation in cattle. The controlled-release properties demonstrated by the matrices indicate their potential as a multimicronutrient functional feed additive to enhance cattle nutrition and productivity. © 2018 Society of Chemical Industry.
有效的微量营养素补充策略对于确保牲畜的最佳健康和生产力至关重要。本研究的目的是开发一种基于壳聚糖凝胶珠的铜和维生素（多种微量营养素）输送系统，并测试其作为牛饲料添加剂在体外的适用性。
壳聚糖与硫酸铜螯合，生成毫米级凝胶基质（~2mm）。通过调整 pH 值至碱性条件后，铜含量显著增加（从 61 增加到 95mg/g）。随后可以将模型维生素核黄素负载到高达 324μg/g 珠的水平。在模拟瘤胃液中对干燥的凝胶基质进行限制再水化，导致核黄素的持续释放，在这些中性条件下 24 小时内没有铜释放，从而实现了铜的瘤胃旁路。此外，在 pH 2 的皱胃条件下，在 3 小时内观察到矿物质的持续释放。
这些基质显示出铜的瘤胃旁路，但在皱胃条件下提供了营养上相关的游离矿物质水平，这是牛有效补充所需的。基质表现出的控制释放特性表明它们有可能作为一种多种微量营养素功能性饲料添加剂，以提高牛的营养和生产力。© 2018 英国化学工业学会。
