A new biokinetic model for iodine in dairy cows was developed utilizing data from a 4 × 4 factorial feeding experiment with rumen-cannulated cows that were fed rapeseed cake containing substances known to influence iodine metabolism, and soybean meal without such effects. 131I was administered both intravenously and intra-ruminally to document metabolism pathways. The new model included compartments such as saliva and thyroid gland, often ignored in other models, and in contrast to previously available biokinetic models, it fitted well to our experimental data. Compared to cows fed soybean meal diet, rapeseed cake diet resulted in lower retention of 131I in body compartments, reduced 131I transfer to milk, and increased urinary excretion of 131I. Over time, low retention of iodine from diets containing goitrogenic substances like rapeseed would increase the risk of iodine deficiency, in both cattle and humans. Based on sensitivity analysis, milk, blood and liver pathways contributed the most to the model uncertainty. The proposed model should be relevant in elucidating mechanisms governing iodine uptake and metabolism in dairy cows, to predict how feeding can be used to optimize iodine concentrations in milk, and to reduce transfer of radioiodine through dairy products in case of fallout from nuclear events.

中文翻译：

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碘转移到牛奶中：一种修订的生物动力学模型


利用 4 × 4 因子喂养实验的数据开发了一种新的奶牛碘生物动力学模型，该实验使用瘤胃罐头奶牛喂食含有已知影响碘代谢的物质的菜籽饼和没有这种影响的豆粕。131I 通过静脉内和瘤胃内给药以记录代谢途径。新模型包括唾液和甲状腺等隔室，这些隔室在其他模型中经常被忽略，与以前可用的生物动力学模型相比，它与我们的实验数据非常吻合。与饲喂豆粕日粮的奶牛相比，油菜籽饼日粮导致 131I 在体腔中的保留较低，131I 转移到牛奶中的减少，以及 131I 的尿液排泄增加。随着时间的推移，从含有油菜籽等致甲状腺肿物质的饮食中碘的低保留会增加牛和人类缺碘的风险。根据敏感性分析，牛奶、血液和肝脏通路对模型不确定性的贡献最大。所提出的模型应该与阐明控制奶牛碘摄取和代谢的机制相关，以预测如何使用饲料来优化牛奶中的碘浓度，以及在核事件沉降物的情况下减少放射性碘通过乳制品的转移。