摘要
本试验旨在比较不同日龄肉鸡对常规与低蛋白质饲粮净能利用效率和氨基酸标准回肠消化率的差异。试验分2个试验进行,试验1:分别选择7日龄爱拔益加(AA)肉鸡48只、17日龄AA肉鸡48只和30日龄AA肉鸡24只,每个日龄阶段分为2组[分别饲喂常规饲粮(饲粮粗蛋白质水平为23%)和低蛋白质饲粮(饲粮粗蛋白质水平为21%)],每组6个重复,每个重复4或2只鸡。每期试验7 d,其中预试期4 d,正试期3 d。采用家禽12室联排开路式呼吸测热装置分别测定肉鸡11~14日龄、21~24日龄和35~38日龄呼吸数据。试验2:分别选择7、17和30日龄AA肉鸡各108只,每个日龄阶段分为3组,每组6个重复,每个重复6只鸡。3组肉鸡分别饲喂常规饲粮、低蛋白质饲粮和无氮饲粮,并分别于10、20和33日龄时开展屠宰试验,测定氨基酸标准回肠消化率。结果表明:1)与常规饲粮相比,低蛋白质饲粮对3个日龄阶段肉鸡生长性能均无显著影响(P>0.05),显著降低肉鸡21~24日龄氧气消耗量(P<0.05)。2)与常规饲粮相比,低蛋白质饲粮显著提高肉鸡11~14日龄代谢能/总能值(P<0.05);显著降低21~24日龄总产热、热增耗和蛋白质沉积能(P<0.05),显著提高净能/代谢能值(P<0.05);显著提高35~38日龄净能(P<0.05)。3)与常规饲粮相比,低蛋白质饲粮显著降低肉鸡7~10日龄丙氨酸和酪氨酸标准回肠消化率(P<0.05),显著提高组氨酸标准回肠消化率(P<0.05);显著提高17~20日龄甘氨酸、胱氨酸、酪氨酸、丝氨酸、苏氨酸、天冬氨酸和缬氨酸标准回肠消化率(P<0.05);对30~33日龄氨基酸标准回肠消化率无显著影响(P>0.05)。综上所述,与常规饲粮相比,低蛋白质饲粮会显著降低肉鸡21日龄后产热量,提高净能利用率;净能体系可以更有效判断饲粮蛋白质水平对肉鸡的影响,有利于精准测定肉鸡对低蛋白质饲粮的能量代谢参数并分析体内能量调控方向;在肠道发育完善后,肉鸡对低蛋白质饲粮的氨基酸标准回肠消化率低于常规饲粮。
The aim of this experiment was to compare the differences in dietary net energy utilization efficiency and amino acid standardized ileal digestibility between conventional diet and low-protein diet in broilers of different days of age.The experiment was divided into two tests.In test 1,48 Arbor Acres(AA)broilers at 7 days of age,48 AA broilers at 17 days of age and 24 AA broilers at 30 days of age were selected and divided into two groups at each day-age stage with 6 replicates per group and 4 or 2 chickens per replicate,and fed a conventional diet with 23%crude protein level and a low-protein diet with 21%crude protein level,respectively.Each trial lasted for 7 days,including 4 days of pre-trial period and 3 days of trial period.The respiratory data of broilers from 11 to 14 days of age,21 to 24 days of age and 35 to 38 days of age were measured by an open-circuit respiratory calorimetry instrument with 12 chambers in parallel for poultry.In test 2,each 108 AA broilers of 7,17 and 30 days of age were selected,and each day-age stage was divided into 3 groups with 6 replicates per group and 6 chickens per replicate,respectively.Broilers in the three groups were fed the conventional diet,low-protein diet and nitrogen-free diet,respectively,and slaughter trial was conducted at 10,20 and 33 days of age,respectively,to determine the amino acid standardized ileal digestibility.The results showed as follows:1)compared with the conventional diet,the low-protein diet had no significant effects on growth performance of broilers at 3 day-age stages(P>0.05),and significantly decreased the oxygen consumption of broilers from 21 to 24 days of age(P<0.05).2)Compared with the conventional diet,the low-protein diet significantly increased the metabolic energy to gross energy ratio of broilers from 11 to 14 days of age(P<0.05);significantly decreased the total heat production,heat increment and retain energy as protein from 21 to 24 days of age(P<0.05),and significantly increased the net energy to metabolic energy ratio(P<0.05);significantly increased the net energy from 35 to 38 days of age(P<0.05).3)Compared with the conventional diet,the low-protein diet significantly decreased the standardized ileal digestibility of alanine and tyrosine of broilers from 7 to 10 days of age(P<0.05),and significantly increased the histidine standardized ileal digestibility(P<0.05);significantly increased the standardized ileal digestibility of glycine,cystine,tyrosine,serine,threonine,aspartate and valine from 17 to 20 days of age(P<0.05);had no significant effects on amino acid standardized ileal digestibility from 30 to 33 days of age(P>0.05).In conclusion,compared with the conventional diet,the low-protein diet can significantly reduce the heat production and increase the net energy utilization rate of broilers after 21 days of age;the net energy system can more effectively judge the effects of dietary protein levels on broilers,and is conducive to accurately determine the energy metabolism parameters of low-protein diets in broilers and analyze the direction of energy regulation in vivo;after intestinal development was complete,the amino acid standardized ileal digestibility of low-protein diets in broilers was lower than that of conventional diets.
作者
班志彬
陈思淼
徐莹
闫晓刚
刘永发
李立佳
李柏浩
张琦玉
呙于明
BAN Zhibin;CHEN Simiao;XU Ying;YAN Xiaogang;LIU Yongfa;LI Lijia;LI Baihao;ZHANG Qiyu;GUO Yuming(State Key Laboratory of Animal Nutrition,College of Animal Science and Technology,China Agricultural University,Beijing 100193,China;Institute of Animal Nutrition and Feed,Jilin Academy of Agricultural Sciences,Gongzhuling 136100,China)
出处
《动物营养学报》
北大核心
2025年第1期296-306,共11页
CHINESE JOURNAL OF ANIMAL NUTRITION
基金
国家重点研发计划资助(2021YFD1300404)
家禽能量营养联合研究中心横向委托鸡饲料原料净能评价及数据库建立项目(PENC2021001)。
关键词
肉鸡
日龄
低蛋白质饲粮
净能
氨基酸标准回肠消化率
broilers
days of age
low-protein diet
net energy
amino acid standardized ileal digestibility
