Abstract: The present experiment was carried out to determine the effects of ascorbic acid and high levels folic acid added to layer hen diets on live weight gain, feed intake, feed efficiency, egg production and egg quality. A total of 270 Lohmann LSL type white layer hens at 28th weeks of age were used in the experiment. Experiment was conducted with a control and 5 experimental groups each containing 45 hens. The layers were fed basal diet, supplemented as follows; 200 mg kg-1 ascorbic acid (AsA), 5 mg kg-1 folic acid (FA1), 10 mg kg-1 folic acid (FA2), ascorbic acid + 5 mg kg-1 folic acid (AsA+FA1) and ascorbic acid+ 10 mg kg-1 folic acid (AsA+FA2). The groups, which had AsA+FA1 in diet, had higher body weight compared to the other groups at the end of the experiments (p<0.01). Feed intake was improved by addition of AsA+FA2 (p<0.05), but feed conversion was not effected in the group supplemented folic acid and/or ascorbic acid. Mean egg production was highest in the group including AsA and lowest in FA1 group (p<0.01). The average weights of eggs and egg mass were effected in the AsA+FA combination (p<0.05). Different levels of folic acid with or without ascorbic acid supplementation to basal diet did not produce statistically important effects on some egg quality or egg shell weight. Addition AsA+FA2 to layer diet caused a statistical increased on means shell thickness (p<0.001). As a result of this study, supplementation of ascorbic acid and high levels folic acid to diet positively affected live weight, feed intake and shell thickness during the early laying period.
I. Abas , R. Kahraman , H. Eseceli and N. Toker , 2008. The Effect of High Levels of Folic Acid on Performance and Egg Quality of Laying Hens Fed on Diets with and Without Ascorbic Acid from 28-36 Weeks of Age. Journal of Animal and Veterinary Advances, 7: 389-395.