Determination of the best level of dietary metabolizable energy of pullets in the rearing periods

An experiment was conducted to study the effect of different dietary metabolizable energy levels on performance of Lohmann LSL-Lite strain pullets at the rearing periods. A total of 196 3-week old chicks were randomly allocated to 7 experimental diets with different metabolizable energy levels (2400، 2500، 2600، 2700، 2800، 2900 and 3000 Kcal/kg)، 4 replicates per diet and 7 birds per replicate pen. Level of metabolizable energy 2800 Kcal/kg as the control group was considered، and all data were analyzed in a randomized complete block design. Mash feed and water were available for ad libitum consumption. Total of the rearing periods was divided to 3 periods: grower (4-8 weeks)، developer (9-16 weeks) and prelaying (17-18 weeks). Comparing the results of other diets with control diet at the entire periods showed that reducing the level of dietary metabolizable energy up to 2500 Kcal/kg do not significantly affect feed intake (P>0. 05) and feed conversion ratio (P>0. 01)، in addition to، the cost of this metabolizable energy level was significantly lower than control diet. Under the conditions of this experiment، the conclusion based on feed conversion ratio in each period show that the best level of metabolizable mnergy in growth، development، and the prelaying periods، respectively can be 2600، 2500 and 2700 Kcal/kg diet.