Effect of Different Dietary Energy Levels in the Rearing Periods on Performance and Productive Traits of Laying Hens During the Laying Cycle (19-28 weeks)

An experiment was conducted to study the effects of different dietary energy levels in the rearing period on performance and productive traits of layer hens during the laying cycle. 196-day-old layer chicks were randomly assigned to 7 treatments (2400, 2500, 2600, 2700, 2800, 2900 and 3000 Kcal ME/kg), with 4 replicates of 7 birds each. The treatment containing 2800 Kcal ME/kg was considered as the control group. Results showed that feeding different dietary energy levels had no effect on feed intake and weight gain (P>0.05). Even though, feed to egg ratio was increased by reduction of dietary energy levels, decreasing energy levels up to 2400 Kcal ME/kg had no significant effect as compared to control group (P>0.05). Feed intake per dozen eggs and egg number per hen were not affected by reducing energy level up to 2500 Kcal ME/kg, as compared to control group (P>0.05). In addition, diluting the dietary energy up to 2600 and 2700 Kcal ME/kg had no effect on egg production and time of laying commencement, respectively (P>0.05). In conclusion, feeding the treatment containing 3000 Kcal ME/kg, not only improved performance and productive traits, but also increased the average weight of each egg when compared to other treatments (P