Effects of Dietary Protein Level and Betaine Supplementation on Nutrient Digestibility and Performance of Japanese Quails

ABSTRACT This study investigated the effects of dietary protein levels and betaine supplementation on nutrient digestibility and performance of Japanese quails. In total, 765 Japanese quails were randomly assigned to a 3×3 factorial arrangement, with five replicates of 17 quails each. Three basal diets were formulated to contain three crude protein levels (16.5, 18.0, and 19.5%). Each protein level was supplemented with 0, 0.06, and 0.12% betaine. The diet with 16.5% dietary crude protein with no betaine supplementation resulted in the lowest crude fiber digestibility, while the 18.0% CP diet...