Levels of metabolizable energy and crude protein on laying rate and egg quality of laying quails

This study evaluated the zootechnical performance of 192 laying quails, receiving diets with different levels of crude protein (18 and 19%) and metabolizable energy (2,500, 2,600, 2,700 and 2,800 kcal/kg), in a 2 x 4 factorial arrangement. The experiment consists of four experimental periods of 28 days each, where feed intake (g/bird), feed conversion (by dozens of eggs and egg mass), laying rate, weight and mass of eggs and indices of egg quality (yolk, shell and albumen content, shell thickness, Haugh unit). Results indicated that reducing feed energy levels to 2,500 and 2,600 kcal/kg increased feed intake (P < 0.05). However, reducing protein levels to 18% did not change (P > 0.05) feed intake. No differences (P > 0.05) were observed in laying rate, feed conversion per dozen eggs and egg mass, and egg quality indices, in relation to energy or protein levels. There were no interactions between dietary energy and protein levels. In conclusion, the reduction of metabolizable energy levels to 2,500 kcal/kg and crude protein to 18% in diets for laying quails, from 52 to 68 weeks of age, is a viable alternative to reduce production costs, without harming performance and egg quality.