Department of Veterinary Science, Universidade Federal do Paraná, Rua dos Funcionários, Curitiba, Brazil.
Department of Animal Science, Universidade Federal do Paraná, Curitiba, Brazil.
Anim Sci J. 2022 Jan-Dec;93(1):e13716. doi: 10.1111/asj.13716.
We aimed to evaluate the effects of the reduction in dietary crude protein (CP) on blood urea, uric acid, performance, immunity, and intestinal histology of broilers. Four diets were formulated with 22.50%, 21.50%, 20.50%, and 19.50% of CP (1 to 21 days) and 19.20%, 18.20%, 17.20%, and 16.20% of CP (22 to 42 days), meeting the requirements of essential amino acids in all diets. A total of 800 male Ross chicks were randomly allocated to 32 pens, with 25 birds each (n = 8). Blood and intestines had been collected for analysis. Uric acid decreased and urea increased with the reduction of CP (p < 0.05). Reduction in performance and intestinal parameters (villus, crypt, and goblet cells) was observed with the reduction of CP (p < 0.05). Lower levels of CP resulted in alteration (p < 0.05) in CD4 and CD8 lineages (21 and 42 days). Broken-line models estimated (p < 0.05) the CP requirement for growth between 21% and 21.3% (1 to 21 days) and between 17.2% and 17.4% (22 to 42 days) and CP requirements between 17.2% and 18.2% for maximum response of immune cells (42 days). Reduction in dietary CP has a negative impact on performance, immune response, and intestinal histology of broilers, even with adequate levels of essential amino acids.
我们旨在评估降低饲粮粗蛋白（CP）对肉鸡血液尿素氮、尿酸、生产性能、免疫和肠道组织学的影响。设计了 4 种饲粮，CP 水平分别为 22.50%、21.50%、20.50%和 19.50%（1-21 日龄）和 19.20%、18.20%、17.20%和 16.20%（22-42 日龄），所有饲粮的必需氨基酸需求都得到满足。将 800 只雄性罗斯小鸡随机分配到 32 个围栏中，每个围栏 25 只（n=8）。收集血液和肠道进行分析。随着 CP 的降低，尿酸降低，尿素增加（p<0.05）。随着 CP 的降低，生产性能和肠道参数（绒毛、隐窝和杯状细胞）下降（p<0.05）。较低的 CP 水平导致 CD4 和 CD8 谱系（21 和 42 日龄）发生改变（p<0.05）。折线模型估计（p<0.05），1 至 21 日龄和 22 至 42 日龄生长的 CP 需要分别为 21%和 21.3%以及 17.2%和 17.4%，而 42 日龄免疫细胞的最大反应需要 17.2%至 18.2%的 CP。即使饲粮中必需氨基酸水平充足，降低饲粮 CP 水平对肉鸡的生产性能、免疫反应和肠道组织学有负面影响。
