Institute of Agricultural and Nutritional Sciences, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany.
Institute of Agricultural and Nutritional Sciences, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany.
Nutrition. 2014 Apr;30(4):481-4. doi: 10.1016/j.nut.2013.10.002. Epub 2013 Oct 14.
Food-based strategies need to be developed to improve the vitamin D status of individuals. Recent studies identified ultraviolet B irradiation as an efficient method to enrich mushrooms and eggs with vitamin D. The aim of this study was to determine whether free-range farming of hens could provide a valuable method to produce vitamin D-enriched eggs.
Laying hens were randomly assigned to three groups of 33 to 34 animals each, and were kept either indoors (indoor group), outdoors (outdoor group), or with an indoor/outdoor option (indoor/outdoor group) over 4 wk.
The study shows that the vitamin D3 content of egg yolk was three- to fourfold higher in the groups that were exposed to sunlight (outdoor and indoor/outdoor groups) compared with the indoor group (P < 0.001). Egg yolk from the outdoor group revealed the highest vitamin D3 content, which averaged 14.3 μg/100 g dry matter (DM), followed by that from the indoor/outdoor group (11.3 μg/100 g DM). Yolk from indoor eggs contained only 3.8 μg vitamin D/100 g DM. The 25-hydroxyvitamin D (25[OH]D3) content of egg yolk was also influenced by sunlight exposure, although less pronounced than the vitamin D content (P < 0.05). In contrast, free-range eggs randomly acquired from supermarkets had relatively low vitamin D contents.
Free-range farming offers an efficient alternative to fortify eggs with vitamin D, provided that farming conditions are sufficiently attractive for hens to range outside.
需要制定基于食物的策略来改善个体的维生素 D 状况。最近的研究表明，紫外线 B 照射是一种有效方法，可以使蘑菇和鸡蛋富含维生素 D。本研究旨在确定散养母鸡是否可以提供一种有价值的方法来生产富含维生素 D 的鸡蛋。
将产蛋母鸡随机分配到三组，每组 33 到 34 只，分别在室内（室内组）、室外（室外组）或室内/室外（室内/室外组）饲养 4 周。
研究表明，与室内组相比，暴露在阳光下的组（室外组和室内/室外组）蛋黄中的维生素 D3 含量高出三到四倍（P<0.001）。室外组蛋黄中的维生素 D3 含量最高，平均为 14.3μg/100g 干物质（DM），其次是室内/室外组（11.3μg/100g DM）。室内鸡蛋的蛋黄仅含有 3.8μg 维生素 D/100g DM。蛋黄中 25-羟维生素 D（25[OH]D3）的含量也受到阳光照射的影响，尽管不如维生素 D 含量明显（P<0.05）。相比之下，从超市随机购买的散养鸡蛋的维生素 D 含量相对较低。
只要饲养条件对母鸡有足够的吸引力，让它们在户外活动，散养就为鸡蛋补充维生素 D 提供了一种有效的替代方法。
