现在人们越来越青睐有机食品,但英国一项最新研究显示,鸟儿在选择食物的时候并不偏爱有机食品,反而更喜欢吃那些施化肥种植的小麦。
英国纽卡斯尔大学研究人员在新一期《粮食和农业科学杂志》上报告说,他们进行了为期三年的实验,在冬天鸟儿不易找到食物的时候,在几个公园设置了几十个喂食点,每个喂食点都有两个相邻且外观相同的喂食装置,内装相同品种的小麦,区别在于一个装置里面是通过有机方式种植的小麦,而另一个装置里面是施化肥种植的非有机小麦。
结果发现,鸟儿更喜欢吃那些非有机小麦。实验一段时间后,研究人员还互换了两种小麦的位置,不过鸟儿很快就发现了这个变化,仍然更多地食用非有机小麦。此外,在实验室中喂养的金丝雀也表现出同样的择食倾向。
研究人员分析认为,施用含氮元素的化肥后,小麦粒中的蛋白质含量比有机小麦平均高10%,而对于在冬天不易找到食物的鸟儿来说,补充蛋白质非常重要。
参与这一研究的麦肯齐博士说,研究结果表明,认为有机食品更好的观点未必总是正确,虽然这项研究没有涵盖非有机食品中化肥和农药残余物的长期影响等问题,但它的确说明非有机食品在营养上也有其优点。
现在的有机食品一般指用天然种植或饲养方式得到的食品,这类食品在生产和加工过程中严格遵守相关标准,禁止使用化学合成的农药、化肥、激素、抗生素、添加剂等。(生物谷Bioon.com)
生物谷推荐原文出处:
Journal of the Science of Food and Agriculture doi:10.1002/jsfa.4025
Birds select conventional over organic wheat when given free choice
Ailsa J McKenzie *, Mark J Whittingham
School of Biology, Newcastle University, Ridley Building, Claremont Road, Newcastle upon Tyne NE1 7RU, UK
BACKGROUND: Global demand for organic produce is increasing by 4 billion annually. One key reason why consumers buy organic food is because they consider it to be better for human and animal health. Reviews comparing organic and conventional food have stated that organic food is preferred by birds and mammals in choice tests.
RESULTS: This study shows the opposite result - that captive birds in the laboratory and wild garden birds both consumed more conventional than organic wheat when given free choice. There was a lag in preference formation during which time birds learnt to distinguish between the two food types, which is likely to explain why the present results differ from those of previous studies. A further experiment confirmed that, of 16 potential causal factors, detection by birds of consistently higher levels of protein in conventional seeds (a common difference between many organic and conventional foodstuffs) is the likely mechanism behind this pattern.
CONCLUSION: The results of this study suggest that the current dogma that organic food is preferred to conventional food may not always be true, which is of considerable importance for consumer perceptions of organically grown food.