Effect of different levels of dietary metabolizable energy on laying performance of Khorasan Razavi native hens

An experiment was carried out to investigate the effects of different levels of energy (2400, 2500, 2600, 2700, 2800 and 2900 kcal/kg) on laying performance of Khorasan Razavi native hens. Three hundred 38-week-old native laying hens during Three 28-day periods were put into 30 groups of ten chickens, which were randomly allocated to six experimental diets. Each treatment was replicated five times in completely randomized design. The trial lasted for 12 weeks. All birds were given free access to water and diets. The results indicated that there were no significant differences in egg production, egg weight and egg mass at the end of the experiment. Daily feed intake (DFI) and feed conversion ratios (FCR) were significantly decreased as energy level of the diet was increased (P<0.05) when treatments 2, 1 and 3 (ME=2800, 2900, 2700 Kcal/kg) had the lowest DFI  whereas treatments 5, 6 (ME=2500, 2400 Kcal/kg) had highest DFI , respectively. FCR was influenced by dietary energy level. Hens on the diet with 2800 Kcal ME /kg had the lowest (2.66) FCR compared to 2400 Kcal ME/kg that the highest FCR (3.65). The results showed that a diet containing 2800 Kcal ME/kg adequately satisfied the maintenance and production requirements of Khorasan Razavi native hens during 38-50 week of production. Also, this ration was more economical.