Effect of dietary folic acid supplementation on the folate content of broiler chicken meat.

The B-vitamin folate is an essential nutrient required for a number of metabolic functions including DNA synthesis and the provision of methyl groups in numerous reactions. Clinical folate deficiency causes anaemia, while low folate status leads to an increased risk in the occurrence of neural tube defects and has, more recently, been associated with an increased risk of cardiovascular disease. Thus, it is important that an adequate level of folate is supplied in the human diet. However, typical diets in the UK and elsewhere in Europe do not provide sufficient folate and therefore the folate status of the general population is below the optimum level. Whilst dietary supplements of folic acid (the synthetic form of the vitamin) are available, there is scope for improving the intake of natural folate by increasing the level in human foods. House et al. (2002) supplemented laying hen diets with folic acid and reported an increase in the amount of folate in eggs. The aim of this study was to investigate if supplementation of broiler diets with folic acid could increase the level of folate within broiler chicken meat. A secondary aim was to establish the effect of folic acid supplementation of broiler diets on overall performance. Commercial starter and finisher broiler diets containing 3 mg/kg folic acid were supplemented with 0, 2, 4, 8, 16 and 32 mg/kg folic acid and offered to a total of 240 one-d-old chicks for a period of 42 d. The birds were grouped in pens of 20 according to weight, with two groups per treatment. On d 21, eight birds were removed from each pen to ensure optimum stocking density, three of which were utilised to obtain blood, liver, thigh and breast samples for determination of folate level. Similarly, on d 28, 35 and 42, three birds were removed to determine the folate level of blood serum, liver, thigh and breast. Folate level was measured by thermal extraction with tri-enzyme treatment followed by microbiological assay with Lactobacillus casei (Molloy and Scott 1997; Tamura 1998). Daily feed intake (DFI), average daily gain (ADG) and feed conversion ratio (FCR) were calculated for the entire experimental period (42d). Analysis of variance was conducted using Genstat 6. Serum folate levels increased linearly with increasing folic acid supplementation (Table).