Forty-eight Hour Feed and Water Deprivation after Hatching Is Detrimental to Subsequent Broiler Per- Formance. Early Post-hatch Starvation Induces Myonu- Clear Effect of Keratinase Supplementation in Broiler Starter Diets with Three Different Levels of Crude Protein

s of papers 25 and β-glucanase, except a low level of α-amylase activity (85,000 U/gm vs. 19,000,000 U/gm pure α-amylase). Results of chick growth at 21 d showed positive (P < 0.05) main effects of CP level and enzyme supplementation on BW and FCR. Birds receiving diets with higher CP content had higher BW (800 gm at 23% vs. 722 gm at 17% CP, P < 0.05). Birds fed diets supplemented with keratinase showed higher final BW than those fed identical diets without keratinase (853, 850, and 731 gm vs. 800, 808, and 722 for diets containing 23%, 21%, and 17% CP with or without enzyme, respectively). In addition, there was a positive interaction between the enzyme and CP level on BW and FCR. Diets containing higher levels of CP responded better to enzyme supplementation than those with lower CP content. Results of this experiment indicated that the growth performance of broiler chicks receiving adequately formulated diets could be further improved by dietary supplementation with the keratinase. Since zero or very low activities of other tested enzymes were found in the crude keratinase preparation, the contribution from those enzymes in growth performance is believed to be minimal.