Effect of dietary folate and vitamin B12 on egg composition and liver triglyceride of laying hens at 64 weeks of age

The experiment was conducted to determine the effects of supplemental dietary folate and vitamin B12 on egg composition, reproductive traits and triglyceride content in liver of laying hens at 64 weeks of age. Four levels of dietary folate (0, 0.5, 4 and 10 mg/kg) and three levels of dietary vitamin B12 (0, 0.01 and 0.08 mg/kg) were fed in 4x3 factorial in a complete randomized design. The basal diet was based on corn and soybean meal. There were four replicates of twelve layers per each treatment. The experimental diets and water were offered ad libitum for 8 weeks. The results showed that egg production, feed intake, egg weight, egg mass, oviduct weight, liver weight, and liver triglyceride of the hens were not affected by both folate and vitamin B12 supplementation (P>0.05). However, increasing the vitamin B12 caused significantly higher ovary weight (2.75, 2.67 and 3.03% of BW.) and albumen percentage (64.07, 64.27 and 64.93%), but significantly lower yolk percentage (26.36, 26.10 and 25.62%) and yolk:albumen ratio than the unsupplemented group (0.41, 0.40 and 0.39%) (P<0.05).