SUMMARY Worldwide, commercial laying hens are frequently being used for only one production cycle mainly due to a decline in egg quality and/or egg quantity at 70–80 weeks of age. Extending the production cycle of these hens by improving or maintaining their egg quality and laying persistency could lead to both economic and environmental benefits as well as a more sustainable egg industry. Laying performance of the modern-day laying hen is highly dependent upon the light source used during housing and artificial lighting programmes have been used for years to control egg production. Birds are able to perceive coloured light (400–700 nm) as well as the ultraviolet (UV) part of the spectrum (100–400 nm) due to the presence of an extraretinal cone in the eye. Studies have shown that red light, due to its longer wavelength of 660 nm, is able to stimulate the hypothalamus and elicit a photosexual response in all animals including birds. This can result in increased egg production in comparison to green, blue or white light exposure, although responses may vary depending on bird strain and the intensity of the light used. UV light has a shorter wavelength (100–400 nm) than visible light (400–700 nm) and so its effects on egg production are likely to be weak to non-existent. The benefits of UV light are mediated through its ability to activate cholecalciferol from 7-dehydroxycholesterol in the skin resulting in improvements in eggshell quality. These improvements in shell quality are most likely to occur in birds that are exposed to (natural) daylight, as UV light can compensate to some extent, the lack of vitamin D in poultry diets. This review highlights the variable effects of light of different wavelengths and intensity on laying hen production, egg quality and its potential to extend the end of lay in commercial hens.

中文翻译：

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不同波长光对蛋鸡产量和蛋品质的影响

总结 在世界范围内，商品蛋鸡经常只用于一个生产周期，这主要是因为在 70-80 周龄时鸡蛋质量和/或鸡蛋数量下降。通过改善或保持鸡蛋质量和持续产蛋来延长这些母鸡的生产周期，可以带来经济和环境效益以及更可持续的鸡蛋产业。现代蛋鸡的产蛋性能高度依赖于鸡舍期间使用的光源，并且多年来一直使用人工照明程序来控制产蛋量。由于眼睛中存在视网膜外锥体，鸟类能够感知有色光（400-700 nm）以及光谱的紫外线（UV）部分（100-400 nm）。研究表明，红光由于波长较长，为 660 nm，能够刺激下丘脑并在包括鸟类在内的所有动物中引起光性反应。与绿光、蓝光或白光照射相比，这会导致产蛋量增加，尽管响应可能会因禽类品种和所用光的强度而异。紫外线的波长 (100-400 nm) 比可见光 (400-700 nm) 短，因此它对产蛋量的影响很可能微弱甚至不存在。紫外线的好处是通过其从皮肤中的 7-脱羟基胆固醇激活胆钙化醇的能力介导的，从而改善蛋壳质量。这些蛋壳质量的改善最有可能发生在暴露于（自然）日光下的鸟类身上，因为紫外线可以在一定程度上弥补家禽日粮中维生素 D 的缺乏。