Effect of dietary metabolizable energy and crude protein levels on performance of lingnan yellow-feathered broiler breeders | 日粮代谢能和蛋白质水平对30―39周龄岭南黄羽肉种鸡繁殖性能的影响

Chinese. 【目的】研究日粮中不同代谢能（ME）和蛋白质（CP）水平对产蛋高峰期（30―39周龄）岭南黄羽肉种鸡生长性能、产蛋性能和孵化性能的影响。【方法】采用3（ME：11.09、11.51和11.92 MJ•kg-1）×3（CP：15.5%、16.5%和17.5%）两因子试验设计，选取1 134只健康的30周龄快大型岭南黄羽父母代肉种鸡，随机分成9组，每组6个重复，每个重复21只。试验期10周。统计各个重复的体增重、料蛋比、产蛋率、日产蛋重、平均蛋重、种蛋破损率、不合格蛋比率、受精率、18日活胚率、孵化率和健雏率。【结果】（1）11.92 MJ•kg-1ME处理组试验鸡只的体增重显著高于11.51 MJ•kg-1ME处理组（P＜0.05），极显著高于11.09 MJ•kg-1ME处理组（P＜0.01），其料蛋比显著低于11.51和11.09 MJ•kg-1ME处理组（P＜0.05）；而CP水平对试验鸡只的体增重和料蛋比无显著性影响（P＞0.05）；（2）产蛋性能：11.92 MJ•kg-1ME处理组产蛋率和日产蛋重最高（P＜0.01）；11.51和11.92 MJ•kg-1ME处理组平均蛋重显著高于11.09 MJ•kg-1ME处理组（P＜0.05）；11.92 MJ•kg-1ME处理组种蛋破损率也高于11.51和11.09 MJ•kg-1ME处理组（P＜0.05）；不合格蛋比率以11.09 MJ•kg-1ME处理组最高（P＜0.05），ME和CP水平对试验鸡只不合格蛋比率具有显著的互作效应（P＜0.05）；与CP 15.5%处理组相比，日粮CP水平为16.5%和17.5%时，显著提高了平均蛋重，并显著降低了种蛋破损率（P＜0.05）；（3）孵化指标：日粮ME为11.92 MJ•kg-1或CP为16.5%时，雏鸡初生重显著高于其它处理组（P＜0.05），但各处理组的受精率、18日活胚率、孵化率和健雏率均无显著性差异（P＞0.05）。【结论】30―39周龄岭南黄羽肉种鸡获得最佳繁殖性能的日粮适宜ME和CP水平分别为11.92 MJ•kg-1和16.5%，每日ME和CP需要量分别为1.55 MJ和21.45 g。

English. 【Objective】 This experiment was conducted to investigate different dietary levels of metabolizable energy and crude protein on performance of Lingnan Yellow-Feathered Broiler Breeders. 【Method】 A total of 1 134 30-week-old Lingnan Yellow-Feathered Broiler Breeders were randomly assigned into 3×3 factorial dietary treatments with 3 dietary metabolizable energy (ME) levels at 11.09, 11.51, and 11.92 MJ•kg-1 and 3 crude protein (CP) levels at 15.5%, 16.5%, and 17.5%. Each dietary treatment had 6 replicates with 21 birds per replicate. Experimental birds were fed 130 g of diet per bird every day. Growth performance, laying performance, and egg incubation indicators were determined. The trial lasted for 10 weeks.【Result】Broiler breeders fed 11.92 MJ•kg-1 ME diet had significantly greater weight gain and lower FCR (feed intake/egg mass ratio) when compared with birds of other ME groups (P＜0.01). However, CP levels had no significant influence on weight gain and FCR of broiler breeders (P＞0.05). An increase in dietary ME from 11.09 to 11.92 MJ•kg-1 of diet significantly improved egg production, average egg weight, and daily egg mass (P＜0.05). Diet containing 16.5% CP or 17.5% CP significantly increased the average egg weight and reduced the egg breakage of broiler breeders (P＜0.05) compared to 15.5% CP treatment. There was a significant interaction between ME and CP levels on unqualified egg percentage and hatchability (P＜0.05). Chick birth weight was significantly improved by dietary 11.92 MJ•kg-1 ME and 16.5% CP treatments when compared to 11.09 MJ•kg-1 ME treatment and 15.5% CP treatment, repectively (P＜0.05). 【Conclusion】The results indicated that the optimal dietary ME and CP level for Yellow-Feathered Broiler Breeders at 30-39-week of age was 11.92 MJ•kg-1 and 16.5%, respectively, whose ME and CP requirements as units per hen per day was estimated to be 1.55 MJ and 21.45 g, respectively.