Evaluation the effect of different levels of dietary vitamin D3 on productive and egg quality traits in Japanese quail

The objective of this study was to investigate the additive effect of 1000, 2000, 4000 and 8000 IU/kg of vitamin D3 on the productive and egg quality characteristics in Japanese quail. 320 adult Japanese quail were used. Experiment was done in a randomized complete block design with 5 treatments, 4 replicates and 16 quails in each replicate (12 female and 4 male birds) for 42 days. After 2 weeks of treatments, the productive characteristics of birds were recorded weekly for 6 weeks. At the end of experiment, 5 eggs were selected randomly from each replication and egg quality traits were examined. Feed conversion ratio and also some egg quality parameters including eggshell weight, egg width and diameter of thin albumen were influenced by levels of vitamin D3 (p<0.05). Although the egg quality parameters had no significant difference with control, but the egg shell weight and egg width percent were increased with increase the levels of vitami D3 from 4000 (15.90 and 2.67, respectively) to 8000 (14.41 and 2.51, respectively) IU/kg (p<0.05). The feed conversion ratio in 4000 IU/kg of vitamin D3 (3.68) was significantly lower than the control (4.22) (p<0.05). The other egg quality characteristic as well as feed intake, percentage of egg production and egg weight were not affected by treatments (p<0.05). The results of this study show the improvement of feed conversion and eggshell weight and egg width in Japanese quail's, especially at the level of 4000 IU/kg of vitamin D.