Effect of nutrients density on growth performance, carcass parts and growth curve characteristics in Japanese quails

In this experiment, 1032 one-day-old Japanese quails were randomly divided into 4 dietary treatment groups with 3 replicates of 86 quails in each. The treatment groups were: 1) group with low dietary nutrient concentration [95% of nutrients recommended by NRC (1994), -5% NRC], 2) group with medium dietary nutrient (DN) concentration [100% of nutrients recommended by NRC (1994)], 3) group with high DN concentration [105% of nutrients recommended by NRC (1994), % NRC] and 4) group with very high DN concentration [110% of nutrients recommended by NRC (1994), % NRC]. Feed intake was affected by dietary treatments only during 0-21 d period, with a lesser of feed consumption for group 1 compared to the other groups. Body weight gain was increased in harmony to the nutrient concentration in all phases of the experiment. The best feed conversion ratio was achieved by % NRC. Except for the relative weights (% of live weight) of thigh muscle, pancreases and gizzard, there were no significant differences between the dietary treatments for other carcass parts. According to the Gompertz function, asymptotic weight (Wf) was higher in % NRC (295 g) than the other dietary treatments (269, 292.7 and 290 g for -5% NRC, NRC and % NRC, respectively) as was the case with growth rate constant (b: 0.059, 0.059, 0.061 and 0.061 for -5% NRC, NRC, % NRC and % NRC, respectively). The range of age and weight at point of inflection were from 19.7 to 20.8 d and 99.3 to 108.7, respectively.