Folate and regulation of immune and anti-oxidant defense mechanisms in the laying hen

2006年，加拿大的家禽和蛋业占加拿大农业总收入的7.0%，相当于26亿美元。在过去的50年里，家禽业在营养、遗传、工程和管理等多个领域取得了重大进展，从而最大限度地提高了生产效率，包括生长和鸡蛋生产。营养素的供应有不同的目标：1)满足蛋鸡的维护和生产需求；2)确保有足够的营养储备，以对应激源(环境、微生物、病毒、毒物等)做出有效反应；以及3)根据消费者的喜好优化或提高鸡蛋的营养状况。总体而言，该行业一直专注于实现第一个目标，因为这构成了生产者获得传统经济回报的基础。因此，对于某些关键营养素，公布的值可能低估了实现确保最佳母鸡健康或提高鸡蛋营养浓度这一额外目标所需的营养素。水溶性维生素叶酸就是这样一种营养素，目前的需求量可能被低估了。在以前的研究中，申请人提供了强有力的证据，证明如果叶酸摄入量超过蛋鸡需要量估计，鸡蛋中的叶酸含量可以增加2-3倍，而且鸡蛋中发现的天然叶酸是高度可用的。此外，这项研究还提供了证据表明，超过目前行业使用的叶酸补充量会显著减少硫代氨基酸同型半胱氨酸，这是一种已证明有可能引发细胞损害的代谢物。目前的建议将通过研究蛋鸡叶酸吸收和代谢的调节机制，以及面对免疫挑战时叶酸状态对母鸡健康指标的影响来推进我们的初步观察。该研究计划将通过促进与特种鸡蛋市场未来发展有关的知识，以及通过确定提高禽类健康的新方法，对鸡蛋行业产生直接影响。

In 2006, the poultry and egg industries in Canada accounted for 7.0% of total Canadian agricultural receipts, an amount equivalent to $2.6 Billion. During the past five decades, the poultry industry has made great steps in several areas including nutrition, genetics, engineering, and management, thereby maximizing the efficiency of performance, including growth and egg production. Nutrients are supplied with distinct goals in mind: 1) meeting the maintenance and production needs of the laying hen; 2) ensuring adequate nutritional reserves to mount an effective response to a stressor (environmental, microbial, viral, toxicological, etc...) ; and 3) optimizing or enhancing the nutritional profile of the egg relative to consumer preferences. In general, the industry has focused on achieving the first goal, as this has formed the basis of the traditional economic returns to the producer. Therefore, for certain key nutrients, the published values may underestimate those needed to meet the additional goals of ensuring optimal hen health or enhanced egg nutrient concentrations. The water soluble vitamin folate reflects one such nutrient where current requirements are likely underestimated. In previous research, the applicants have provided strong evidence that egg folate contents can be enriched by 2-3 fold with folic acid intakes in excess of laying hen requirement estimates, and that the natural folate found in the egg is highly available. Furthermore, this research has provided evidence that folic acid supplementation above that currently employed in the industry yields significant reductions in the sulphur amino acid homocysteine, a metabolite with documented potential to invoke cellular damage. The current proposal will advance our initial observations by investigating the mechanisms regulating folate uptake and metabolism in the laying hen, and the impact of folate status on indices of hen health in the face of an immune challenge. The research program will have direct implications for the egg industry by advancing knowledge pertaining to the future development of the specialty egg market, and through the identification of novel methods to enhance bird health.