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

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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.