Vitamin D supplementation to improve laying hen robustness, longevity, and egg quality

这一伙伴关系旨在提高蛋鸡的稳健性，以更好地应对营养、免疫和环境压力，从而在延长产蛋周期的背景下提高它们的生产力和寿命。事实上，成功地将蛋鸡保持在100周不再是例外，商业鸡群的蛋鸡周期有延长到每个周期500个蛋的趋势。长寿蛋鸡期望在生产中帮助节约成本，创造附加值和利润，提高鸡的福利，减少鸡蛋生产对环境的影响。然而，耗尽鸡群的主要原因通常不是与持续生产鸡蛋有关，而是因为蛋壳质量随着年龄的增长而逐渐下降。劣质鸡蛋，尤其是较弱的蛋壳，会增加鸡蛋包装的成本和客户投诉。这可能是随着年龄增长而出现的骨质疏松症的结果，这可能会导致福利问题和经济损失。最近的研究结果显示，随着年龄的增长，成纤维细胞生长因子23(FGF23)的表达增加，而维生素D的活性形式1.25(OH)2D3的血浆水平下降(Gloux)。维生素D是众所周知的蛋鸡必需营养素，通过促进肠道对钙和磷的吸收，促进骨骼矿化和动员，从而确保良好的蛋壳质量(Bar，2008)。因此，维生素D可以帮助延长产蛋周期，同时减少对母鸡的潜在负面影响。除了维生素D对蛋鸡健康的好处外，研究还表明，鸡蛋中维生素D的生物强化对人类健康是可能的。这一合作伙伴关系的具体目标将是测试添加更活跃形式的维生素D长达90周，以预防其对磷和钙状况、肠道健康、免疫力和整体表现的影响。

This partnership aims to improve the robustness of laying hens to better cope with nutritional, immune, and environmental stresses and thus improve their productivity and longevity in a context of lengthening of laying cycles. Indeed, successfully keeping the laying hens to 100 weeks is no longer the exception and there is a tendency for extending the laying hens cycle of commercial flocks to reach 500 eggs per cycle. The long-life laying hen are expecting helping saving costs in production, create additional value and profit, improve the welfare of the chicken, and reduce the environmental impact of egg production. However, the main reason to deplete a flock is not often related to the persistency in egg production, but because of eggshell quality that gradually goes down with age. Poor quality eggs, and especially weaker shells, can increase the costs of egg packing and customer complaints. This is probably the result of the osteoporosis that occurs with ageing that may lead to both welfare issues and financial losses. Recent results have showed an increase expression of Fibroblast Growth Factor 23 (FGF23) and a decreased plasma levels of 1.25(OH)2D3, the active form of vitamin D, with ageing (Gloux). Vitamin D is a well-known essential nutrient in laying hens which contributes to bone mineralization and mobilization by promoting the intestinal absorption of Ca and P and thus ensures good shell quality (Bar, 2008). Vitamin D could thus help extending the laying cycle while reducing the potential negative impact for the hen. Beyond the interest of vitamin D for the health of laying hens, studies have shown the possibility of biofortification in vitamin D in eggs for human health. The specific objectives of this partnership will be to test the addition of a vitamin D in a more active form up to 90 weeks of laying in terms on its prophylactic effect on phosphorus and calcium status, gut health, and immunity and overall performances.