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.

Dietary folate and vitamin B12 supplementation and consequent vitamin deposition in chicken eggs

“…In the present study, yolk folate content in the hens fed 10.31 mg folate/kg diet was higher by about 40% than that in the hens fed a basal diet (0.31 mg/kg diet). This result agrees with the report of Hebert et al (2005) that maximal egg folate levels were achieved when dietary folate concentrations exceeded the recommendation of 0.25 mg of folate/kg of diet given by NRC (1994). Sherwood et al (1993) reported that the normal folate concentration in egg yolk is approximately 43-fold higher than that in blood plasma from which yolk folate is taken up.…”

“…This result indicates that laying hens have highly efficient conservation and delivery systems for folate (Sherwood et al 1993). The result that egg yolk and serum folate concentrations reached saturation when hens were supplemented with a very high level of dietary folate agrees with the findings by Hebert et al (2005) and Sherwood et al (1993) that the saturation of plasma folate concentrations represents a putative control point for egg folate concentrations. However, House et al (2002) reported that the saturation limit of egg folate content was not due to limitations in transport processes from serum to egg yolk.…”

“…Recently, Luchtel et al (2008) indicated that dietary egg white protein has a significant impact on homocysteine metabolism and is extremely effective in the prevention of hyperhomocysteinemia. On the other hand, vitamin B 12 in eggs seems to be poorly absorbed (<9%) relative to other animal food products (Watanabe 2007), whilst more than 95% of folate in egg is located in the yolk and enrichment of eggs with folate is possible when dietary folate levels are increased (Sherwood et al 1993;Hebert et al 2005). Hence, increasing folate and vitamin B 12 in egg through dietary supplementation may be necessary for pregnant women, older adults and people in rural areas, and enhancing the levels of these vitamins in eggs may promote better health in these individuals.…”

Improvement of flock productivity through supply of vitamins for higher laying performance and better egg quality

“…Hens fed a commercial, folate-sufficient diet (0.72 mg folate/kg) produced eggs with slightly less than half of the maximal folate content. However, when laying hens were supplemented with 0, 2, 4, 8, 16, 32, 64 or 128 mg/kg of crystalline folic acid for 21 days, laying performance was not affected (Hebert et al, 2005). Considering plasma homocysteine concentrations, a strain-specific requirement for folic acid could be deduced as the higher egg mass producing strain benefited from increased folic acid through a reduction in plasma homocysteine concentrations.…”

Use of FAO food balance sheets to estimate the potential ability of novel folate-enriched eggs to increase the folate supply in European Union countries

“…These strategies include the development of novel foods enriched with natural folates (12) . Recently, several groups have shown that the folate content of eggs can be increased significantly by supplementing the diet of laying hens with folic acid (43)(44)(45)(46)(47)(48) . Most of the additional folate appears in the eggs in the natural form, mainly as 5-methyltetrahydrofolate (48) .…”