15N示踪法对日粮不同蛋白质水平山羊氮代谢的影响

采用15N稳定性同位素示踪技术,将4只(30±3)kg、装有颈静脉血管插管的山羊,按4×4拉丁方设计进行试验,研究了由牧草和精料组成的4种不同蛋白质水平日粮[8.5%(A)、11.0%(B)、13.5%(C)和16.0%(D)]对山羊内源尿素氮代谢的影响.结果表明,日粮蛋白质水平时氮的表观消化率影响较小,各组间差异不显著,但呈现出随氮食入量的增加而升高的趋势;对山羊体内氮的沉积量有显著或极显著的影响,当日粮蛋白质水平为11.0%时,可获得最大氮沉积量0.36 g/(d·W0.75).粪中15N丰度和富集量都呈现出随日粮蛋白质水平的升高先上升而后下降的趋势,尿中15N丰度和富集量都呈现出随日粮蛋白质水平升高而升高的趋势,日粮蛋白质水平对粪和尿中15N峰值出现的时间均影响不大.     

非常规蛋白饲料原料对泌乳山羊氮代谢和微生物蛋白合成的影响

文章旨在研究不同蛋白质来源精饲料对泌乳山羊氮代谢及微生物蛋白合成的影响.试验选择平均初始体重为(43.62±2.35)kg的泌乳期山羊72头,随机分为3组,每组4个重复,每个重复6头.各组分别饲喂以豆粕、大豆浓缩蛋白和豆科植物(银合欢)为基础的精料,试验为期8周.结果:大豆浓缩蛋白组尿液和尿素氮排泄量较豆科植物组显著提...     

日粮蛋白质水平对断奶仔猪氮代谢的影响

试验研究了日粮不同蛋白质水平对断奶仔猪氮代谢的影响。试验采用完全随机设计,将72头35日龄断奶的仔猪分为4组,每组3个重复,每个重复6头。4个组分别饲喂24%、22%、20%、18%蛋白水平的日粮。结果表明:粪氮排泄随日粮蛋白水平的升高而增加,24%蛋白组粪氮排泄量显著高于其它3组(P<0.05),尿氮变化不显著;22%、20%、18%蛋白组氮表观消化率无显著差异,24%蛋白组氮表观消化率显著低于其它3组(P<0.05);氮代谢率随蛋白水平上升而下降;血清总蛋白浓度与日粮蛋白水平无显著的相关性;血清尿素氮浓度随日粮蛋白水平的降低而降低。总之,考虑到仔猪生长和氮排出,仔猪日粮蛋白水平应以20%~22%为好,18%的日粮蛋白水平影响仔猪日沉积氮量。     

不同日粮氮水平对山羊氮代谢和微生物蛋白质合成的影响

本试验旨在探讨不同日粮氮水平对内蒙古白绒山羊氮代谢和微生物蛋白质合成(MCP)的影响,以达到提高氮利用率,减少环境污染和饲料资源的浪费。试验选用9只体况良好、体重为(43.83±2.95)kg,装有瘤胃瘘管的内蒙古白绒山羊,按体重随机分为3组,每组3只。日粮分为低氮7.5%、中氮10.5%、高氮13.5%3个氮水平。试验使用常规试验方法分析测定粪尿血液等生化指标,通过全收尿法和尿嘌呤衍生物法估测MCP。结果表明:随着氮水平增加,氨氮(NH3-N)浓度、氮摄入量、尿氮排出、尿中尿素氮(UUN)和MCP显著增加(P0.05),干物质采食量(DMI)显著降低(P0.01);沉积氮占总摄入氮的比例在中氮组最高,MCP在高氮组最高。综上所述,适当降低日粮氮水平可减少粪尿氮排放,提高反刍动物氮利用率。     

不同蛋白源日粮对山羊胃肠道氨基酸及肽的影响

试验选择4头体况良好且安装有永久性瘤胃瘘管和十二指肠瘘管的徐淮白山羊,采用4×3不完全拉丁方设计,配制蛋白水平相同但牧草蛋白来源不同的4组日粮,分别为A(苜蓿、羊草和稻草)、B(羊草和苜蓿)、C(羊草)、D(苜蓿和稻草),旨在研究不同蛋白组成日粮对山羊胃肠道氨基酸和肽的影响。结果表明,D组日粮蛋白质消化率和蛋白质沉积量最高。各处理组瘤胃内游离氨基酸、肽氨基酸浓度分别为25.58、26.64、26.03、26.86 mg/100 mL和22.82、24.25、23.53、25.73mg/100 mL;十二指肠食糜中游离氨基酸、肽氨基酸浓度分别为32.52、33.52、33.37、33.93 mg/100 mL和22.39、23.53、23.02、24.21 mg/100 mL。瘤胃液和十二指肠中游离氨基酸和肽氨基酸浓度的日变化趋势,均是在采食2 h后降低,4 h后达到峰值。从蛋白质的消化率和进入十二指肠的氨基酸组成来看,苜蓿和稻草组合的D组瘤胃降解率最高,饲喂山羊效果最好。     

日粮不同NDF水平对山羊内源氮流量的影响

以装有瘤胃、十二指肠、回肠瘘管的山羊为试验动物。采用拉丁方试验设计,探讨4种NDF水平分别为40.70%、38.37%、34.28%、30.36%的日粮对山羊十二指肠、回肠内源氮流量的影响。结果表明:在该试验条件下,日粮NDF水平在30%～40%范围时,十二指肠、回肠内源氮流量差异不显著(P>0.05)     

日粮蛋白质水平对生长期闽南黄牛氮代谢的影响

选用9头14月龄闽南黄牛公牛,按重复3×3拉丁方设计,进行了氮平衡试验。研究了日粮蛋白质水平对氮消化与沉积规律及血液某些相关指标的影响。结果表明:随着蛋白质水平的提高,氮的进食量显著增加;氮的表观消化率、氮沉积量也显著增加(P<0.01)。氮的表观消化率(％)=43.26+0.58X,(r=0.9412,n=9);沉积氮(g/d)=1.86+0.37X,(r=0.9216,n=9)。     

山羊对不同植物蛋白质日粮养分的代谢利用研究

试验选用4只装有瘤胃瘘管、十二指肠瘘管的山羊,饲喂不同植物蛋白质的日粮(A、B、C、D4组),用全收粪尿法研究山羊在不同蛋白质日粮下对CP、CF、Ca、P和DE的影响。结果表明:①CP表观消化率,B组与C、D组均差异极显著(P<0.01),B组与A组差异显著(P<0.05),A组与C、D两组差异显著(P<0.05)。②CP表观生物学价值,B组最高,其余依次是D、C、A组,差异不显著(P>0.05)。③CF表观消化率,C组与D组差异显著(P<0.05)。④Ca的消化率,A组与D组差异极显著(P<0.01),与C组差异显著(P<0.05),而与B组无显著差异;B组与D组差异显著(P<0.05)。⑤P消化率,A组与B、C两组有极显著差异(P<0.01),B组和C组之间不存在显著差异,B组和D组之间有极显著差异(P<0.01),C组和D组之间有极显著差异(P<0.01)。⑥各组间DE差异不显著。     

基础日粮中添加尿素或铵盐对湖羊氮代谢的影响

<正>引言 反刍动物氮代谢的特点之一是在利用饲料蛋白质的同时,也能利用非蛋白氮(NPN)合成微生物蛋白供机体利用。尿素是常用的NPN化合物。许多研究证明,日粮中尿素氮占总氮量的25～35％时,反刍家畜仍有良好的生产性能。脂肪酸铵盐是近年来受到重视的另一类NPN化合物,因为它们不仅可以补充氮源,而且还能为微生物的蛋白质合成提供能量和碳架。本研究在由精料和稻草组成的低蛋白基础日粮中添加等氮量的尿素和混合挥发性脂肪酸铵盐(肥皂工厂的一种含氮废液),比较它们对湖羊氮代谢的影响。     

日粮蛋白质水平对梅花鹿营养物质消化代谢的影响

试验选择4头三锯梅花鹿 ,按4×4拉丁方设计 ,进行了氮平衡试验。研究了日粮蛋白质水平对氮消化与沉积规律及血液某些相关指标的影响。结果表明 ,随着日粮蛋白质水平的提高 ,氮的进食量显著增加 ;氮的表观消化率、氮沉积量也显著增加。随着食入氮量的提高 ,血清尿素氮浓度直线上升。     

15N同位素示踪技术在动物蛋白质代谢研究方法中的应用

氮素是动物营养最重要的元素之一，准确研究蛋白质(氮素)的代谢对于动物饲养标准的修订、饲料原料营养参数的准确性和合理配制日粮具有重要意义。同位素示踪技术在农业中的应用，重点讨论了稳定同位素15N示踪技术在动物营养研究特别是在蛋白质代谢研究中应用的先进性、准确性和可行性。     

~(15)N标记法研究不同精粗比底物对山羊瘤胃内原虫与细菌间蛋白质微循环的影响

以4头安装永久瘤胃瘘管的徐淮山羊为试验动物,运用15N稳定性同位素示踪技术,研究了1∶9(A)、3∶7(B)、5∶5(C)、7∶3(D)四种精粗比底物下瘤胃原虫与细菌间蛋白质微循环的影响。结果表明:不同精粗比底物显著影响瘤胃内原虫的吞噬量及微生物蛋白(MCP)的微循环,A、B、C、D四组吞噬N量分别为:18.11×105、21.16×105、20.95×105、30.34×105pg/(mL·h)。每天每头山羊由于原虫的吞噬造成的细菌蛋白循环量分别为:1.09、1.27、1.26、1.82g,其中以C组循环率最大(2.79%),D组蛋白质循环量最高,而B组循环率最低(1.94%),且蛋白质周转量仅为D组的69.78%,可有效减少菌体蛋白循环量。     

Effect of dietary protein level on nitrogen metabolism in lambs: studies using 15N-nitrogen

Six wether lambs (31 kg) were randomly assigned to two treatments (three lambs/treatment): a high protein intake (HP; 21 g N/d) or a low protein intake (LP; 12 g N/d). Each lamb received 860 g/d dry matter (DM) of a pelleted diet (75% corn-soybean meal, 25% cottonseed hulls) offered hourly in 24 equal portions. Single injections of 15N-labelled compounds were made into the ruminal NH3-N and blood urea-N pools to measure the rate of flux through, and transfer of N between, these and the bacterial N pool. Total tract digestibilities of DM and N were lower (P less than .05) for the LP than the HP treatment. Abomasal flows of total, feed or bacterial N tended to be greater (P greater than .05) in lambs fed HP than LP. Lambs fed HP excreted more (P less than .01) urinary N, yet retained a greater (P less than .01) amount of N than lambs fed LP (6.2 vs 1.8 and 9.7 vs 4.1 g N/d, respectively). Pool size and production rate for both ruminal NH3-N and blood urea-N were greater (P less than .05) for the HP than LP treatment. Lambs consuming HP degraded more (P less than .05) blood urea-N in the gastro-intestinal tract (13.4 vs 6.9 g N/d); however, lambs fed LP degraded a greater (P less than .05) percentage of synthesized body urea-N (88.7 vs 71.8%). Ruminal NH3-N absorption was greater (P less than .01) for the HP than LP treatment (3.1 vs .5 g N/d). Although the percentage of bacterial N derived from ruminal NH3-N was similar (P greater than .05) between diets (51.1 vs 63.9), a greater (P less than .05) percentage of bacterial N was derived from blood urea-N in lambs fed LP than HP (77.1 vs 30.2%). Lambs fed LP incorporated a greater (P less than .10) amount of blood urea-N into bacterial N than lambs fed HP (5.5 vs 2.6 g N/d). These data are interpreted to suggest that blood urea-N may provide a substantial quantity of N for bacterial protein synthesis and, thus, may be an important source of protein in the deficient animal. In addition, urea recycling may play an important role in the recovery of ruminal NH3-N lost through absorption in animals fed a high level of protein.     

不同蛋白质结构日粮对山羊瘤胃内环境的影响

安装永久性瘤胃瘘管的山羊4只,采用4×4拉丁方设计,选用不同比例稻草、苜蓿干草、羊草与配合精料组成4种日粮,研究对瘤胃内环境的影响。结果表明:瘤胃液pH值、氨氮浓度和尿素氮浓度在5.94～6.43、16.42～29.82、0.48～0.78mg/100ml内波动,各组间差异不显著;4组瘤胃液FAA浓度为25.58～26.86mg/100ml,组间差异不显著(P>0.05);PAA中,A组(22.82mg/100ml)极显著低于B组(24.25mg/100ml)和D组(25.73mg/100ml)(P<0.01),B组和C组(23.53mg/100ml)显著低于D组(P<0.05)。     

Effect of dietary dry matter intake on endogenous nitrogen flows in growing lambs

The effect of dietary dry matter intake (DMI) on endogenous nitrogen (N) flows at different part of the digestive tract of growing lambs was determined using a ¹⁵N isotope dilution technique. Three Kazakh male lambs (30 ± 2.75 kg of body weights and 4 months old, average daily gain 200 g/day) were fitted with ruminal, duodenal and ileal cannulae and raised in metabolic cage individually. The experiment was conducted in a 3 × 3 Latin square design with three lambs, three DMI levels (1100, 920 and 736 g/day respectively) and three periods. Each period lasted 18 days, consisting of 10 days for adaptation, 8 days for the continuous infusion of l ‐[¹⁵N]leucine, during which the intestinal flow of N and ¹⁵N enrichment were determined. The total endogenous secretions in the forestomach (S_fs) were decreased (p = 0.0512) with increased level of DMI. On the contrary, endogenous nitrogen (EN) secretions into the small intestine (S_i) increased (p = 0.0249) significantly with the high level of DMI (HI) group compared with that of low level of DMI (LI). Total absorption from forestomach was reduced (p = 0.0121) with increased level of DMI, whereas total absorption from small intestine for HI group increased (p = 0.0116) significantly compared with that of LI treatment. The real digestibility of N in the rumen accompanied with the increase in feed intake is decreased (p = 0.081). In contrast, there were no effects of DMI level on the computed real digestibility of N across both small intestine and whole tract. The results of this study indicate that the total flows of EN at duodenum may be unaffected by the level of DMI; however, the EN flow at ileal level increased from 12% to 37% with the increase in DMI level, corresponding to 33% of total N flow at ileum.     

Effect of the content of crude plant protein in the ration on the utilization of urea in dairy cattle. 2. 15N-urea metabolism

The metabolism of 15N-urea in the rations of dairy cows was investigated in dependence on the crude protein content of the rations. With energy concentration remaining unchanged, the rations contained 10.7 (I), 13.7 (II) and 17.1 (III)% plant crude protein and, after the supplementation of 150 g urea per animal and day, a total of 13.8, 16.7 and 20.2% crude protein in the dry matter. The urea was intraruminally infused during the feeding in the morning and the evening. In the morning feeding of each 1st measuring day it was labelled with 27.5 atom-% 15N-excess (15N'). The degree of labelling with 15N' of the N-fraction of rumen fluid, contents of the duodenum, faeces and milk, precipitable with trichloric acetic acid (TCA) decreased with the rising protein level of the ration. This effect was bigger than could be expected considering the low 15N'-quota in the total-N of the ration. In the sequence I ... III, 52.7, 32.2 and 30.6% of the 15N'-amount taken in passed the duodenal re-entrant cannula in TCA-precipitable form within 72 hours after the 15N-application. 33.3, 21.9 and 22.6% were apparently absorbed in the intestines as TCA-precipitable N within 120 h after the 15N'-application. In the same period 31.7, 43.1 and 72.8% of the 15N' taken in were excreted in urine. 12.3, 9.6 and 5.8% of the applied 15N' were found in milk protein. One can conclude that the utilisation of urea-N decreases with the rising level of crude protein in the ration and that, however, urea-N is still biochemically utilised when there is an excess of plant-N in the ration.     

不同蛋白质水平对中卫山羊妊娠母羊日粮消化性能的影响

选择体重、年龄相近健康的妊娠母羊30只,随机分为3组。每组10只。采用相同能量水平、不同蛋白质水平的日粮饲养。试验结果表明,在本试验条件下,日粮蛋白质含量以116.57g/d比较有利于中卫山羊妊娠母羊的生长发育。     

不同能量蛋白水平日粮对崂山奶山羊消化代谢的影响

本试验选用12只健康的经产崂山奶山羊,分为4组,即高能高蛋白组(简称HH组)、高能低蛋白组(简称HL组)、低能高蛋白组(简称LH组)和低能低蛋白组(简称LL组),每组3只,采用全收粪尿法进行消化代谢试验。结果表明:HH组的产奶量显著高于LH组和LL组(P<0.05),进食氮、尿氮、粪钙、进食磷显著高于LL组(P<0.05),HH组和LH组的尿氮、粪钙显著高于HL组和LL组(P<0.05);HL组尿氮显著低于其他各组(P<0.05),HH组和LH组的肌酐(CRE)显著低于HL组(P<0.05);HH组乳脂肪含量显著低于其他各组(P<0.05),其他指标各组间差异不显著(P>0.05)。分析表明,高能量水平(NE=5.3 MJ/kg)有利于提高崂山奶山羊的采食量和产奶量,低蛋白水平日粮(CP=12.5%DM)可提高氮的表观消化率4%～5%,有利于氮的消化和利用。