Dietary crude protein and metabolizable energy levels on laying quails performance

This work was developed to evaluate the effect of different levels of crude protein (CP) and metabolizable energy (ME) on the performance of laying quails. Six hundred and seventy tywo Japanese quails (Coturnix coturnix japonica) from 42 days to 168 days of age were divided in six periods of 28 days each. The birds were assigned to a completely randomized design, with the treatments in a factorial arrangement of 4 x 4 (protein x energy), with six replication of seven birds per experimental unit. The levels evaluated were: 16, 18, 20 and 22% of crude protein and 2,585; 2,685; 2,785 and 2,885 kcal of metabolizable energy/kg of diet. The treatments did not showed significantly effect on the energy intake and egg production. However, the increase in energy level caused a linear reduction in feed intake, protein intake, egg weight and eggs mass; while, the increase in protein level caused a linear increase in daily intake of crude protein, eggs mass, feed conversion and variation in body weight of the birds and a quadratic effect on the egg weight. The estimated level of crude protein in the diet to obtain the maximum egg weight was 21,16%. It was concluded that Japanese quails regulate feed intake according to the energy level of the diet. In order to obtain higher egg production and better feed conversion diets for laying quails the diets should contain 2,585 kcal ME/kg and 18% crude protein. However, if the objective is to obtain heavier eggs, the protein level in the should increase to 21.16%.