title: Effect of dietary folic acid supplementation on egg folate content and the performance and folate status of two strains of laying hens.
abstract: Enrichment of eggs with folate is possible when dietary folic acid levels are increased. However, development of optimal strategies for the production of folate-enriched eggs requires knowledge as to differences due to strain of bird and a greater understanding of the factors limiting egg folate deposition. To this end, a study was designed to determine the response of two leghorn strains that differ in production performance. Hyline W36 and W98 hens (n = 6 per diet) received a barley-based ration containing 0, 2, 4, 8, 16, 32, 64, or 128 mg/kg of crystalline folic acid for 21 d. Response criteria included production parameters, measures of blood folate status, and egg folate content. Significant (P < 0.05) main effects of folate supplementation were observed for egg folate content and plasma folate, which increased, and homocysteine concentrations, which decreased with supplementation; performance, however, was not affected. The Hyline W98 strain had significantly (P < 0.05) higher total egg and yolk weights and feed consumption when compared with the W36. Significant (P < 0.05) ration x strain interactions were observed for egg and yolk weight, egg folate content, and plasma homocysteine. The higher egg mass producing strain, Hyline W98, benefited from increased folic acid through a reduction in plasma homocysteine concentrations, suggesting that this strain has a higher requirement for folate than the W36 strain. Overall, egg folate content is maximized when crystalline folic acid is supplemented to the diet at 2 mg/kg or higher. Higher levels of egg folate are not achieved due to the saturation of the precursor pool for egg folate deposition.
authors.affiliation: Department of Animal Science, University of Manitoba, Winnipeg, MB, Canada.
authors.forename: K
authors.initials: K
authors.lastname: Hebert
authors.forename: J D
authors.initials: JD
authors.lastname: House
authors.forename: W
authors.initials: W
authors.lastname: Guenter
mesh_terms: D000821:Animal Feed; D000818:Animals; D002645:Chickens / Q000145:classification* / Q000502:physiology*; D004032:Diet; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004530:Egg Yolk / Q000737:chemistry*; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage* / Q000032:analysis* / Q000494:pharmacology; D010058:Oviposition / Q000502:physiology
chemical_list: D005492:Folic Acid