Mahdie Nikbakhetzadeh; Heydar Zarghi; َAbolghasem Golian
Volume 22, Issue 1 , March 2020, , Pages 105-116
Abstract
The aim of this study was to investigate the effect of finisher diet nutrient density and slaughter age on energy and protein retention efficiency of broiler chickens. Three hundred 23-day-old Cobb-500 male broiler chickens were assigned in a 5×2 factorial arrangement of completely randomize ...
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The aim of this study was to investigate the effect of finisher diet nutrient density and slaughter age on energy and protein retention efficiency of broiler chickens. Three hundred 23-day-old Cobb-500 male broiler chickens were assigned in a 5×2 factorial arrangement of completely randomize design with 10 treatments, 6 replicates and 5 birds each. The experimental treatments included five nutrient levels of finisher diets (102.5, 100, 97.5, 95, and 92.5% levels of nutrient composition recommendations stated by the Cobb-500 Commercial Management Guide) and two slaughtered ages (38 and 46 days of age). As increased dietary nutrient density significantly and l inearlyincreased weight gain, feed efficiency, energy and protein retention efficiency and decreased maintenance energy requirements per unit of weight gain (P<0.05). By increasing slaughter age from d38 to d46, above indices significantly deteriorated (P<0.05). The highest residual feed intake belonged to birds fed the finisher diet with 97.5% of strain recommendation nutrients level. Dietary nutrient density level for optimal weight gain, feed efficiency, and energy and protein retention efficiency by linear broken line models were estimated 101.7, 98.7, 97.7 and 99.5% of strain recommendation, respectively. Whereas, these values were 2.3-5.5 percent less than those estimated by the quadratic broken-line model. As a conclusion, residual feed intake methodology can be a viable alternative to measure dietary energy efficiency. Formulation broiler finisher diet with nutrients concentration lowers than 97.5% of strain recommendation is not suitable.
Heydar Zarghi; َAbolghasem Golian; Ahmad Hassanabadi; Farhad Khaligh
Volume 20, Issue 4 , February 2019, , Pages 577-587
Abstract
The present study was conducted to determine the zinc (Zn) requirement in broiler chickens fed wheat-soy based diet. Two hundred fifty day-old broiler chicks (Ross 308), were randomly assigned to a completely randomised design (CRD) experiment with 5 treatments, and 5 replicates of 10b each. The experimental ...
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The present study was conducted to determine the zinc (Zn) requirement in broiler chickens fed wheat-soy based diet. Two hundred fifty day-old broiler chicks (Ross 308), were randomly assigned to a completely randomised design (CRD) experiment with 5 treatments, and 5 replicates of 10b each. The experimental treatments included five dietary Zn levels (30, 70, 110, 150, and 190 mg/kg) provided by the addition of reagent grade “ZnSO4.7H2O”. The experiment lasted from 1-42d of age. Increasing dietary Zn level to 70mg/kg significantly increased 10, 24 and 42d live body weight (LBW), feed intake (FI) and weight gain (WG) during 1-10, 25-42 and 1-42d of age and feed efficiency (FE) during 1-10d of age. The linear broken-line (LBL), quadratic-broken line (QBL) and the quadratic polynomial (QP) regression models were used to estimate the Zn requirement. The Zn requirement for optimal final LBW and FI, WG, and FE during 1-42d of ages by LBL model were 68.77, 83.12, 66.99 and 62.75 mg/kg of diet, and by QBL model 70.00, 79.93, 69.63 and 58.01 mg/kg of diet, respectively. In conclusion, Zn requirement varied between 58-83 mg/kg, which is higher than NRC and is lower than strain recommendation in the broiler chickens fed wheat-based diet.