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

该伙伴关系旨在提高蛋鸡的健壮性，以更好地科普营养，免疫和环境压力，从而在延长产蛋周期的背景下提高其生产力和寿命。事实上，成功地将产蛋鸡饲养到100周已不再是例外，而且有一种趋势是将商业鸡群的产蛋鸡周期延长到每个周期500个鸡蛋。长寿蛋鸡期望能够帮助节约生产成本，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，消耗鸡群的主要原因往往与产蛋量的持续性无关，而是因为蛋壳质量随着年龄的增长而逐渐下降。质量差的鸡蛋，特别是较弱的壳，会增加鸡蛋包装的成本和客户投诉。这很可能是老年人骨质疏松症的结果，这可能导致福利问题和经济损失。最近的结果表明，随着年龄的增长，成纤维细胞生长因子23（FGF23）的表达增加，维生素D的活性形式1.25（OH）2D3的血浆水平降低（Gloux）。维生素D是产蛋鸡中众所周知的必需营养素，通过促进钙和磷的肠道吸收有助于骨矿化和动员，从而确保良好的壳质量（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，鸡蛋中的维生素D生物强化对人类健康有可能。该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周的产蛋，其对磷和钙状态，肠道健康，免疫力和整体表现的预防作用。

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.