Application of incremental program, an effective way to optimize dietary inclusion rate of guar meal in broiler chicks

Abstract

This experiment was conducted to study the possibility of feeding high concentrations of guar meal in broiler diets using incremental program. Two hundred forty, 7-d-old broiler chicks (Ross 308) were randomly assigned to five treatments with four replicates of 15 chicks each, based on a completely randomized design. The broiler chicks received diets containing 0, 3, 6, 9 and 12% of guar meal from 7 to 21days of age (starter period). Except the control group (0%), these levels increased to 6, 9, 12 and 15% during the grower period (21–42days) 9, 12, 15 and 18% during the finisher period (42–49days), respectively. Beta-mannanas (0.66g/kg) and galactanase (0.33g/kg) were also added to all diets. Inclusion of 12% guar meal in starter and 15% in grower diets decreased (P<0.05) daily gain and increased feed:gain compared to the inclusion rates of 6 and 9% in starter and grower diets, respectively. Carcass yield in birds fed diets containing 3, 6 and 9% guar meal was greater than those fed diets containing 9, 12 and 15% or 12, 15 and 18% during starter, grower, and finisher periods, respectively (P<0.05). Dietary treatments had no impact on serum protein and total cholesterol concentrations. However, as dietary inclusion rate of guar meal increased from 0 (control diet) to 18% during the finisher period, serum low density lipoprotein concentration decreased from 23.7 to 4.55mg/100mL (P<0.05). Birds fed the control diet and the highest level of guar meal in finisher diet (18%) had an increased serum total triglycerides level compared to those fed the diet with 15% guar meal (P<0.05). Dietary ileal protein digestibility was not affected by inclusion of guar meal in diets at any levels. These results indicated that, the application of incremental program is an effective way to determine the optimum inclusion rates of guar meal in broiler chick diets. Inclusion of 9, 12 and 15% of guar meal in starter, grower and finisher diets, respectively, can support the performance equivalent to that of broiler chicks fed a typical corn-soybean meal diet.