环境温度对肉用仔鸡尿酸排泄及氮代谢影响的研究

EFFECTS OF ENV1RONMENTAL TEMPEBATURES ONURIC ACID EXCRETION AND NITROGEN METABOLISM IN BROILERS

４０只５周龄“宝星”肉用仔鸡平均分为５组分别在１２．３、１８．１、２２．９、２８．ｏ和３１．３℃处理４周，研究环境温度对尿酸排泄和氮代谢的影响。结果表明，粗蛋白质食入量、干物质排泄量和氮排泄量均与温度呈显著负相关（ｒ＝－０．７１）。蛋白质的表观生物学价值与温度呈显著正相关（ｒ＝０．６７）。氮的沉积率（ＮＲＲ）主要受尿氮排出量的影响，在１２．３～２８℃ＮＲＲ随着温度的升高而升高，故低温可造成蛋白质的浪费。但是，在３１．３℃ＮＲＲ则因氮消化率的下降而降低。尿酸氮占尿氮总量的７６．９±８．７％，尿酸排泄量随着温度的升高而减少。温度和性别对血清尿酸水平有显著影响，母鸡的尿酸排泄量和血清尿酸浓度均高于公鸡。

Forty Starbro broilers,at the age of 5 weeks, were divided into 5 groups kept res-pectively in chambers of 12.3,18.1, 22.9, 28.0 and 31.3℃ for 4 weeks to study theeffects of ambient temperatures (AT) on uric acid (UA) excretion andnitrogen (N)me-tabolism via N-metabolism trial and urinary nitrogen (UN) determination.The results indicated that crude protein (CP) intake, dry matter and UN excretionwere significantly negative correlation (r=-0.71) with AT, and apparent biological va-lue of CP was significantly positive correlation (r=0.67) with AT at the range of12.3 to 31.3℃. N retention rate (NRR) was mainly affected by UN and increased asthe temperature ascended at the ranges from 12.3 to 28.0℃,which indicated that dietary Protein would be wasted at low AT, however, NRR would decrease due to the de-scent of N digestibility at 31 .3℃.N in UA niade up 76.9±8.70% of total UN.UA inexcreta decreased as the AT levels were increased.The content of UA in serum was in-fluenced by temperature and sex, and was higher in female than that in male birds.