【摘要】 本实验选用9只装有瘤胃、十二指肠和回肠瘘管的生长羯羊 ,随机分为3组 ,分别饲喂以玉米为基础的豆饼型、亚麻饼型和血粉型3种不同氮源日粮 ,以Cr2O3 为食糜标记物测定3种日粮下绵羊消化道不同部位的食糜流通量和进入十二指肠的各种氨基酸的流通量与组成。然后 ,在每种日粮下按3×3拉丁方试验设计 ,并按“递减法”由十二指肠瘘管灌注不同氨基酸。在豆饼日粮下分为减色氨酸(Trp)组、减蛋氨酸(Met)组和全量组 ;在亚麻饼日粮下分为减赖氨酸(Lys)组、减精氨酸(Arg)组和全量组 ;在血粉日粮下分为减精氨酸(Arg)组、减蛋氨酸(Met)组和全量组。测定灌注不同氨基酸对绵羊氮平衡、日增量、血浆尿素氮(PUN)和血浆游离氨基酸(FAA)浓度的影响。试验结果表明 :饲喂不同氮源日粮对绵羊瘤胃食糜流通速率(Kp)无显著影响(P=0.11) ,血粉日粮的瘤胃Kp 比豆饼日粮和亚麻饼日粮高。进入十二指肠食糜的总氮和非氨氮(NAN)在3种日粮间无显著差异(P>0.05) ;十二指肠食糜中微生物氮(MN)流通量差异不显著(P=0.72) ,其中饲喂亚麻饼日粮下绵羊十二指肠食糜中的微生物氮流量和微生物氮占非氨氮比(MN/NAN)最高(分别为7.48g/d和55.71 %) ;豆饼日粮次之 ,血粉日粮最低(39.23 %)。饲喂血粉日粮的绵羊十二指肠食糜中氨基酸总量高于豆饼和亚麻?更多还原

【Abstract】 Nine crossbred wethers fitted with ruminal,duodenal and ileal cannula were used to measure nutrient flows in different site of the digestive tract as well as amino acid flows at the duodenum of sheep fed the diets containing soybean meal(SBM),linseed meal(LSM)and blood meal(BM)as nitrogen sources.Under each diet, three 3×3 Latin squares arrangement of treatments were used to determine limiting amino acide by “removal technique "of duodenal amino acid infusion.Treatments were divided into SBM diet(removal of Trp,removal of Met and all infusion),LSM(removal of Lys,removal of Arg and all infusion)and BM(removal of Arg, removal of Met and all infusion).The results showed that there were no significant effect of different nitrogen source diets on ruminal digesta passage rate(Kp)(P=0.11).Numerically,the Kp for sheep fed BM diet was higher than that of SBM and LSM. Total nitrogen and nonammonia nitrogen(NAN) were no significant difference among three diets(P>0.05).Microbial nitrogen(MN) flow into the duodenum of sheep was higher when sheep fed LSM diet,the next was SBM diet,and the lowest was BM diet(P=0.72).Total amino acid flow into the duodenum of sheep was higher for BM diet than that for SBM and LSM diets.Moreover,Lys and His of the duodenal EAA were lower when sheep fed BM diet.Met and Trp were lower for SBM diet;and Arg,Met and Phe were lower for LSM diet.Regression analyses of the relation among amino acid profiles in the duodenum(Y) g/100gAA,microbial protein amino acid profiles(X1) and dietary amino acid profiles(X2) in the three diets showed as follows: SBM diet:Y=1.96+0.57X1+0.06X2 (R2=0.91,P=0.008) LSM diet:Y=0.19+0.83X1+0.10X2 (R2=0.81,P=0.08) BM diet:Y=-0.86+0.77X1+0.56X2 (R2=0.86,P=0.02) Under SBM diet,bodyweight gains,retained nitrogen(RN) and retained N/digested N in the sheep were decreased significantly(P<0.05)when removal of Met from duodenally infused AA mixture compared to all amino acid infusion treatement,but no effect of removal Trp on RN,RN/DN in sheep fed SBM diet(P>0.05).Under SLM diet,BWG,RN and RN/DN of the sheep were decreased significantly when Lys and Arg,was removed from AA duodenally infused AA mixtures.Under BM diet,BWG,RN and RN/DN of sheep decreased significantly when Met and Arg,was removed,from duodenally infused AA mixtures(P<0.05).There was no significant effect of removal individual amino acid from duodenally infused AA mixtures on plasma urea nitrogen and plasma free amino acid concentration in the sheep.The ratio of Gly and other amino acids(Gly/OAA) in plasma of the sheep was improved when individual AA from duodenally infused AA mixtures was (P<0.05),which are interpreted by the fact that Met was the first limiting amion acid in growing sheep fed SBM diet,Lys was the first limiting amino acid (extent of limitation was 22%) and Arg was the second limiting amino acid(extent of limitation was 13%)fed LSM diet,Met was the first limiting amino acid(extent of limitation was 30%)and Arg was the second one(extent of limitation was 19%)in the sheep fed BM diet.更多还原