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

We determined the effects of dietary supplementation with folate and vitamin B(12) on lipid metabolism and the deposition of these vitamins in eggs of laying hens (age 64-72 weeks). Four levels of folate (0, 0.5, 4 and 10 mg/kg) and three levels of vitamin B(12) (0, 0.01 and 0.08 mg/kg) were added to the basal diet for 8 weeks in a 4 x 3 factorial completely randomized design study. No significant physiological interaction between folate and vitamin B(12) was evident under our experimental conditions. There was no effect of vitamins supplementation on egg production or feed intake. Supplementation with folate significantly elevated serum (p < 0.01) and yolk (p < 0.05) folate levels. Supplementation with vitamin B(12) did not significantly affect serum or egg yolk vitamin B(12) levels. Supplementation with folate or vitamin B(12) did not significantly affect triglyceride or total phospholipid levels in serum or egg yolk although a positive relationship was observed between dietary folate supplementation and total serum phospholipid (r(2) = 0.68, p < 0.05). The study showed that it is possible to produce folate-enriched eggs. An increase in serum total phospholipids due to dietary supplementation with folate may provide physiological benefits to hens, although we did not observe any strong effects of these vitamins on lipid composition.