Four experiments were conducted to estimate the phosphorus and calcium requirements for weight maintenance and weight gain in Japanese quails during their growth phase from 16 to 36 days. Japanese quails aged 16 days were used for estimating the phosphorous and calcium requirements for weight maintenance or weight gain, with these quails composing each reference slaughter group and the others distributed in a completely randomized design, housed in cages of galvanized wire (33 × 33 × 16 cm) that were stored in acclimatized chambers with specific environmental temperatures. The light programme used during the 20-day experimental period was 24 h of artificial light. Analysis of the data showed that the prediction equations for estimating the phosphorus and calcium requirements for weight maintenance and weight gain of Japanese quails between 16 and 36 days of age were P (g/quail/day) = P *(9.3695 + 7.7397*T) + 9.70*WG, in which P is the phosphorus requirement, and Ca (g/quail/day) = P *(363.99 - 8.0262*T) + 28.15*WG, in which Ca is the calcium requirement, P is BW (kg), T is temperature (°C) and WG (g/quail/day).

Were used 724 quails, with initial weight of 105.05±1.40g to determine the model requirements for European quails 16-36 days old. Were used 384 quails for the maintenance requirement experiment and 240 for the gain requirement experiment and the remaining 100 quails composed the birds of the comparative slaughter. Maintenance requirement: the treatments consisted of four levels of feed offerings (100, 75, 50 and 25% of consumption ad libitum) with four pens and four quails per pen for each climatic environment (18, 24 and 28ºC), being 192 quails for each nutrient under study. Gain requirement: the requirements of the studied nutrients for gain were determined from 240 quails, created and fed ad libitum, being 120 quails for each nutrient studied, that is, 30 quails were slaughtered at 21, 26, 31 and 36 days of age. The quails of the reference slaughter comprise the same as the experiment for determining the maintenance requirement. In conclusion. The prediction equations for estimating the requirements were: 1) Pr (mg/quail/day) = (27.029 + 1.5943 × T) × kg0.75 + 12.24 × WG, in which Pr is the phosphorus requirement, kg0.75 is metabolic weight (kg), WG is weight gain (g/quail/day). 2) Ca (mg/quail/day) = (158.93 - 5.187 × T) × kg0.75 + 23.66 × WG, in which Ca is the calcium requirement, kg0.75 is metabolic weight (kg), WG is weight gain (g/quail/day), T is temperature.

Currently, agro-industrial by-products have increasingly been used in animal feeding, as they constitute an alternative source of nutrients for the animal diet and a way to simultaneously reduce environmental pollution. The objective of this study was to examine increasing levels of inclusion of coconut cake in Japanese quail diets in the laying phase on their production performance and egg quality. A total of 360 Japanese quails were allotted to eight treatments with nine replicates and eight birds per experimental unit, in a randomized-block design. Five diets were formulated: a diet without inclusion of the by-product; and diets containing 3, 6, 9, and 12% coconut cake. The experiment lasted 63 days, with evaluations occurring at every 21 days. The following variables were analyzed: feed intake, laying rate, feed conversion, egg weight, specific gravity, Haugh unit, yolk, albumen and shell percentage, shell thickness, and shell weight. The treatments elicited a positive linear response from laying rate, whereas feed conversion per egg mass decreased linearly. In terms of egg-quality traits, shell percentage was influenced, increasing linearly. Coconut cake inclusion at 12% in the diet of Japanese quail in the laying improved feed conversion per egg mass and increased egg-laying rate and eggshell percentage.