Effects of Dietary Type and Crude Protein Level on Production Performance and Carcass Traits of Sichuan Mountain Black-bone Chicken

This study was designed to investigate the effects of dietary type and crude protein level on production performance and carcass traits of Sichuan mountain Black-bone chicken.The experimental design was a 2×2 factorial arrangement with two dietary types (corn-soybean meal and corn-soybean meal-yeast protein) and two crude protein levels (16.5% and 14.5%).Four hundred and eighty 23-week-old Sichuan mountain Black-bone chicken were randomly divided into 4 groups with 4 replicates per group and 30 chickens in each replicate.The pre-test period lasted for 14 days and the trial period lasted for 120 days.The results showed that the production performance of Sichuan mountain Black-bone chicken was not significantly affected by dietary type (P>0.05),while the average egg weight of dietary crude protein level 16.5% was significantly higher than that of dietary crude protein level 14.5% (P<0.05).It was also demonstrated the average egg weight was significantly affected by the interaction of dietary type and crude protein level (P<0.05),but laying rate,daily egg production,daily feed intake and feed/egg were not significantly affected (P>0.05).However,the carcass traits of Sichuan mountain Black-bone chicken was not significantly affected by dietary type and crude protein level or the interaction of the two factors (P>0.05),although dressing percentage,percentage of eviscerated yield,percentage of half-eviscerated yield,percentage of breast muscle and percentage of leg muscle of the dietary type of corn-soybean meal-yeast protein (crude protein level 16.5%) displayed better value.These results indicated that the average egg weight of Sichuan mountain Black-bone chicken was affected by dietary crude protein level greatly.The dietary type of corn-soybean meal-yeast protein (crude protein level 16.5%) was better for Sichuan mountain Black-bone chicken by comprehensive evaluation of production performance and carcass traits.