运输应激对大鼠空肠形态与热休克蛋白家族mRNA表达的影响

本试验以SD大鼠为试验动物,利用摇床模拟公路运输过程中的摇晃、高温、噪音、饥渴、拥挤、碰撞6个主要的刺激因子,构建了大鼠运输应激模型.应激条件为60 r/min,35℃,每天应激2h.体重为270±20 g,20只SD大鼠被随机均分为4组:对照组、应激1d组、应激2d组、应激3d组.在应激结束后,应激组大鼠体温均显著升高(P＜0.05),体重显著下降(P＜0.05),血清中皮质醇含量显著升高(P＜0.05).试验结果与实际公路运输结果一致,表明运输应激模型构建成立.形态学研究显示,运输应激造成了大鼠空肠组织损伤,与对照组相比从应激第1天到应激第3天空肠绒毛脱落逐渐加剧.荧光定量PCR研究结果则显示,Hsp27,Hsp70和Hsp90 mRNA的表达量也剧烈的升高.本试验研究表明,随着应激时间增加,大鼠空肠损伤逐渐加重,且Hsps mRNA表达量升高,表明Hsps的表达量与运输应激造成空肠的损伤严重程度有关.运输应激后表达量急剧升高的保护性分子Hsps,是动物抵抗运输应激的重要机制之一.     

抗热应激中药对肉鸡肝脏Hsp70表达影响的研究

为了研究抗热应激中药对高温应激下肉鸡肝脏热应激蛋白70(Hsp70)表达的调控效果,试验采用免疫组织化学染色和Western-blot法测定了肝脏中Hsp70的定位定量变化。结果表明:高温应激后,肝脏细胞阳性率明显增加,药方试验组肝脏细胞阳性率高于常温组,但低于高温对照组;West-ern-blot检测结果显示高温对照组、药方试验组肝脏中Hsp70含量显著增加(P0.05),且药方试验组肝脏中Hsp70含量在第3,7天与高温对照组相比显著增加(P0.05)。说明抗热应激中药可通过增加肝脏中Hsp70蛋白含量来提高机体细胞热耐受水平,达到保护作用。     

冷应激对湖羊血清因子及热休克蛋白70 mRNA表达的影响

为研究冷应激对湖羊免疫系统及热休克蛋白70(heat stress proteins 70,Hsp70)的影响,试验分别采用实时荧光定量PCR和ELISA方法检测冷应激前后湖羊肝脏、肺脏、脾脏、淋巴结组织中Hsp70mRNA表达量及血清中白细胞介素-2(IL-2)、白细胞介素-4(IL-4)浓度。结果显示,与冷应激前相比,冷应激后湖羊肝脏、肺脏及脾脏组织中Hsp70mRNA表达量均极显著增加(P0.01),其中肝脏的表达量尤为显著;冷应激后湖羊血清中IL-2、IL-4的浓度均呈下降趋势,其中IL-4浓度下降尤为显著(P0.01)。结果表明,冷应激条件下湖羊各组织中Hsp70mRNA表达增强,可提高动物机体的自我保护机能,增强对外界不良刺激的抵抗力,但细胞因子IL-2和IL-4的浓度下降,表明冷应激抑制机体免疫系统。     

复方中药抗鸡热应激及调控肝脏中HSP70表达的研究

研究复方中药对热应激肉仔鸡生产性能、肝脏HSP70 m RNA水平与蛋白表达的影响。试验选取120只18日龄AA+肉仔鸡,随机分为4组进行试验,即复方中药组、维生素组、纯中药组和阳性对照组。试验结束,每组随机迅速宰杀试验鸡3只,采取肝脏组织,采用实时荧光定量PCR法、H.E染色和Western blot法对热应激肉仔鸡肝脏中HSP70 mRNA水平与蛋白表达进行测定。结果表明,复方中药组、纯中药组肉仔鸡平均日增重分别比阳性对照组增加10.87 g(P0.01)和6.32 g(P0.05),死淘率分别降低10%(P0.05)和16.67%(P0.01),而且复方中药组和纯中药组肉鸡肝脏中HSP70 mRNA水平显著提高,蛋白表达呈动态、不稳定变化。提示本复方中药可提高肉仔鸡机体细胞热耐受水平,提高生产性能。     

热应激致Hsc70出入核与细胞凋亡的关系

旨在探讨热应激对H9c2心肌细胞构成型HSP70(constitutive or cognate HSPs,Hsc70)出入核及细胞凋亡的影响。以42℃作为热应激模型温度,通过转染Hsc70siRNA抑制Hsc70表达,Western blot检测细胞质和细胞核内Hsc70表达,ELISA检测细胞培养液LDH浓度,Annexin V-FITC/PI双染法检测细胞凋亡。结果表明,正常H9c2心肌细胞质Hsc70表达量较高,细胞核中表达量很低,细胞质和细胞核Hsp72表达量非常低。热应激后细胞质Hsc70表达量无显著差异,而细胞核Hsc70热应激30和100min后极显著升高(P0.01),热应激240min后开始降低;细胞质和细胞核Hsp72热应激后显著升高(P0.05或P0.01)。Hsc70抑制表达后,细胞质Hsc70水平显著降低,热应激后Hsc70入核明显减少,但仍然有入核现象;Hsc70抑制表达对细胞质和细胞核Hsp72表达无显著影响。与热应激组相比,热应激+Hsc70siRNA组LDH表达量呈升高趋势,热应激100min两组出现显著差异(P0.05);Hsc70抑制表达后H9c2细胞在热应激后更容易发生凋亡,而且在热应激30和100min内,两组之间存在显著差异(P0.05)。结果提示,热应激可诱使Hsc70出入细胞核,Hsc70抑制表达后热应激诱导Hsc70入核显著降低,细胞损伤加重,细胞凋亡升高。     

甘蔗提取物对热应激大鼠肠道组织形态及肠道雌激素受体表达的影响

本试验旨在探讨大鼠日粮中添加甘蔗提取物(sugar cane extract,SCE)对热应激大鼠肠道组织形态和雌激素受体(ER)表达的影响。选用20只21日龄雌性Wistar Imamichi大鼠,采用2×2双因素(温度、SCE)设计,按体重将大鼠均分为4组,即NC组(常温饲喂基础日粮),NS组(常温饲喂SCE日粮),HC组(高温饲喂基础日粮),HS组(高温饲喂SCE日粮),常温为25℃恒温环境,高温为38℃温控环境暴露3 h,SCE日粮中添加2.16%SCE纯品,试验期42d。结果显示:(1)高温显著降低大鼠体重及肾脏指数,SCE对体重及器官指数无显著影响;(2)高温使十二指肠和空肠上皮细胞脱落,固有层暴露,添加SCE后十二指肠和空肠上皮细胞结构完整,排列整齐。(3)高温使大鼠十二指肠中ERβ显著减少,添加SCE后ERβ显著升高。综上,热应激可诱导大鼠肠道组织形态损伤,SCE对热应激大鼠十二指肠和空肠组织损伤具有一定的缓解作用,且SCE影响热应激大鼠发情期ERβ的表达。     

中药复方应激康对热应激肉鸡HSP70m RNA表达影响的研究

为了研究复方中药对热应激肉鸡肝脏HSP70mRNA表达的调控效果;试验选取120只18日龄AA+肉仔鸡,随机分为4组,即复方中药组、维生素组、纯中药组和高温对照组进行试验,试验后每组迅速宰杀3只试验鸡,取肝脏组织进行HSP70mRNA表达的检测。结果表明:高温应激后,复方中药冲剂组和纯中药冲剂组鸡肝脏中HSP70 mRNA表达显著增加,分别比高温对照组、维生素组高2.98倍、3.28倍和4.66倍、5.13倍,说明本试验复方中药可通过上调HSP70 mRNA表达,提高机体热耐受水平,达到保护细胞作用。     

中药复方对热应激肉兔肠道组织结构及肝脏抗氧化机能的影响

通过研究高温应激对肉兔的肠道组织结构及肝脏抗氧化机能的影响,以及中药复方的调控作用,为研制肉兔抗热应激中药提供试验依据。选取35日龄健康新西兰肉兔随机分为对照组、热应激组、中药组。对照组饲喂于25℃²8℃,65%湿度环境中,热应激组及中药组饲喂于高温(30℃28℃,65%湿度环境中,热应激组及中药组饲喂于高温(30℃³7℃、湿度65%)环境中。经21 d后,采集样品测定各指标,结果表明,热应激可引起肉兔十二指肠、空肠组织结构损伤,导致肠道黏膜机械屏障的破坏,中药复方可维持肠道黏膜结构的正常;热应激可引起肉兔肝脏组织中总抗氧化能力(T-AOC)、超氧化物歧化酶(SOD)指标下降,丙二醛(MDA)含量上升,导致肉兔肝脏组织抗氧化能力下降,中药复方可维持热应激肉兔肝脏抗氧化能力于正常水平,可有效减轻夏季热应激对肉兔的肠道组织结构和肝脏抗氧化能力的损害。     

中药复方对热应激大鼠HSP70、皮质醇、血糖及小肠组织学结构的影响

为了观察热应激状态下大鼠的各项生理生化指标和小肠结构的变化情况以及中药复方对热应激大鼠各项生理生化指标及小肠结构的影响,为中药抗热应激临床提供一定理论依据,试验选取80只Wistar雄性大鼠随机分成1~4组(香薷散组、王老吉组、热应激组、常温组),每组20只,进行7 d的热应激试验。在试验进行3小时、1天、3天、7天时,每组随机取5只大鼠,采集腹主动脉血液,检测皮质醇、血糖和HSP70含量;在试验进行1天、7天采集大鼠十二指肠、空肠、回肠制作切片并观察其组织学结构。结果表明:在试验进行1天、7天时,第1,3组大鼠皮质醇水平极显著高于第4组(P0.01)。在试验进行3小时时,第3组大鼠HSP70水平显著高于第4组(P0.05);在试验进行7天时,第1组大鼠HSP70水平显著高于第4组(P0.05)。在试验进行3小时时第3组与第4组相比大鼠血糖浓度极显著升高(P0.01),1天时第1,2,3组均极显著高于第4组(P0.01),3天时第1,3组与第4组比较极显著升高(P0.01),7天时第1,2,3组均极显著高于第4组(P0.01)。在试验进行1天时,第3组大鼠部分肠绒毛变性、裂解、脱落,局部区域炎性细胞增加;在试验进行7天时,仅第2组个别大鼠小肠样品部分肠绒毛上皮细胞轻微变性,而第3组大鼠部分肠绒毛严重变性、断裂或脱落,基底层部分细胞变性,肠绒毛上皮细胞变性。说明香薷散和王老吉均能不同程度调节热应激大鼠HSP70、血糖、皮质醇水平,有效保护大鼠小肠结构的完整性,并缓解和修复热应激过程中造成的部分损伤。     

大鼠急性冷应激模型的建立

通过分析冷刺激对大鼠血清中细胞因子、皮质酮(CORT)、促肾上腺皮质激素(ACTH)的含量以及外周血淋巴细胞中热休克蛋白70(Hsp70)表达量的影响,构建大鼠急性冷应激模型,旨在为其相关研究提供研究基础。本试验急性冷刺激时间为12h。利用ELISA方法检测各组大鼠血清中IL-2、IL-4、IL-6、IL-10、TNF-α、CORT、ACTH的含量;采用Western blot和qRT-PCR方法检测各组大鼠外周血淋巴细胞中HSP70及mRNA表达量。结果表明,与对照组相比,急性冷刺激组大鼠血清中IL-2和ACTH的含量显著升高(P0.05),IL-4、IL-6、TNF-α和CORT的含量极显著升高(P0.01),IL-10无显著变化(P0.05);外周血淋巴细胞内HSP70及其mRNA表达量呈显著升高水平(P0.05)。成功构建大鼠急性冷应激模型。     

白术、微米白术和白术多糖对断奶仔猪生长性能和肠道形态及微生态区系的影响

试验选用96头平均体重14.82 kg左右的杜×长×大断奶仔猪,随机分成4组,每组3栏,每栏8头(公母各半)。对照组饲喂基础日粮,试验1、2、3组分别添加1%80目白术、0.2%白术多糖和1%微米白术。试验期30 d。结果表明:在生长性能方面,与对照组相比,1%微米白术添加组可显著提高日增重(P0.05)、降低饲料增重比和腹泻率,而且效果优于1%80目白术组和0.2%白术多糖组,在肠道形态和肠道微生态区系方面,与对照组相比,日粮添加1%80目白术、0.2%白术多糖、1%微米白术均可不同程度的提高十二指肠和空肠的绒毛高度,加深十二指肠和空肠的隐窝深度,并且增加肠道微生态区系的多样性,其中以1%微米白术添加组的效果最佳。     

Feline intracranial neoplasia: retrospective review of 160 cases (1985-2001)

The purpose of this study was to determine the frequency of different tumor types within a large cohort of cats with intracranial neoplasia and to attempt to correlate signalment, tumor size and location, and survival time for each tumor. Medical records of 160 cats with confirmed intracranial neoplasia evaluated between 1985 and 2001 were reviewed. Parameters evaluated included age, sex, breed, FeLV/FIV status, clinical signs, duration of signs, number of tumors, tumor location(s), imaging results, treatment, survival times, and histopathologic diagnosis. Most of the cats were older (11.3 +/- 3.8 years). Primary tumors accounted for 70.6% of cases. Metastasis and direct extension of secondary tumors accounted for only 5.6 and 3.8% of cases, respectively. Twelve cats (7.5%) had 2 or more discrete tumors of the same type, whereas 16 cats (10.0%) had 2 different types of intracranial tumors. The most common tumor types were meningioma (n = 93, 58.1%), lymphoma (n = 23, 14.4%), pituitary tumors (n = 14, 8.8%), and gliomas (n = 12, 7.5%). The most common neurological signs were altered consciousness (n = 42, 26.2%), circling (n = 36, 22.5%), and seizures (n = 36, 22.5%). Cats without specific neurological signs were common (n = 34, 21.2%). The tumor was considered an incidental finding in 30 (18.8%) cats. In addition to expected relationships (eg, meninges and meningioma, pituitary and pituitary tumors), we found that lesion location was predictive of tumor type with diffuse cerebral or brainstem involvement predictive of lymphoma and third ventricle involvement predictive of meningioma.     

Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia

Sissay, M.M., Uggla, A. and Waller, P.J., XXXX. Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia. Tropical Animal Health and Production, XXXX. A 2-year abattoir survey was carried out to determine the prevalence, abundance and seasonal incidence of gastro-intestinal (GI) nematodes and trematodes (flukes) of sheep and goats in the semi-arid zone of eastern Ethiopia. During May 2003 to April 2005, viscera including liver, lungs and GI tracts were collected from 655 sheep and 632 goats slaughtered at 4 abattoirs located in the towns of Haramaya, Harar, Dire Dawa and Jijiga in eastern Ethiopia. All animals were raised in the farming areas located within the community boundaries for each town. Collected materials were transported within 24 h to the parasitology laboratory of Haramaya University for immediate processing. Thirteen species belonging to 9 genera of GI nematodes (Haemonchus contortus, Trichostrongylus axei, T. colubriformis, T. vitrinus, Nematodirus filicollis, N. spathiger, Oesophagostomum columbianum, O. venulosum, Strongyloides papillosus, Bunostomum trigonocephalum, Trichuris ovis, Cooperia curticei and Chabertia ovina), and 4 species belonging to 3 genera of trematodes (Fasciola hepatica, F. gigantica, Paramphistomum {Calicohoron} microbothrium and Dicrocoelium dendriticum) were recorded in both sheep and goats. All animals in this investigation were infected with multiple species to varying degrees. The mean burdens of adult nematodes were generally moderate in both sheep and goats and showed patterns of seasonal abundance that corresponded with the bi-modal annual rainfall pattern, with highest burdens around the middle of the rainy season. In both sheep and goats there were significant differences in the mean worm burdens and abundance of the different nematode species between the four geographic locations, with worm burdens in the Haramaya and Harar areas greater than those observed in the Dire Dawa and Jijiga locations. Similar seasonal variations were also observed in the prevalence of flukes. But there were no significant differences in the prevalence of each fluke species between the four locations. Overall, the results showed that Haemonchus, Trichostrongylus, Nematodirus, Oesophagostomum, Fasciola and Paramphistomum species were the most abundant helminth parasites of sheep and goats in eastern Ethiopia.     

Y‐chromosomal variation of local goat breeds of Turkey close to the domestication centre

Genetic variations in chromosome Y are enabling researchers to identify paternal lineages, which are informative for introgressions and migrations. In this study, the male‐specific region markers, sex‐determining region‐Y (SRY), amelogenin (AMELY) and zinc finger (ZFY) were analysed in seven Turkish native goat breeds, Angora, Kilis, Hair, Honaml?, Norduz, Gürcü and Abaza. A SNP in the ZFY gene defined a new haplotype Y2C. All domestic haplogroups originate from Capra aegagrus, while the finding of Y1A, Y1B, Y2A and Y2C in 32, 4, 126 and 2 Turkish domestic goats, respectively, appears to indicate a predomestic origin of the major haplotypes. The occurrence of four haplotypes in the Hair goat and, in contrast, a frequency of 96% of Y1A in the Kilis breed illustrate that Y‐chromosomal variants have a more breed‐dependent distribution than mitochondrial or autosomal DNA. This probably reflects male founder effects, but a role in adaptation cannot be excluded.     

The Prevalence and Intensity of Helminth and Coccidial Infections in Dairy Cattle in Central Kenya

A survey of gastrointestinal parasite infections of young (<6 months old), immature (6–12 months old) and adult (>12 months old) dairy cattle on 16 farms in Kiambu District, Kenya was conducted during a dry season (September 1991 to January 1992) and during a wet season (March to July 1992). The survey was based on monthly coproparasitological examination of cohorts and worm counts in tracer calves. The effects of age, sex, farm and season on the prevalence and intensity of helminth and coccidial infections were determined. Faecal egg and oocyst counts revealed that the overall prevalences were: strongyles (including trichostrongyles) (85.5%), liver flukes (Fasciola gigantica) (34.0%), coccidia (30.9%) and tapeworms (9.6%). Eight species of the protozoan Eimeria were identified, the most prevalent species being E. bovis and E. zuernii. The most prevalent nematode genera were Haemonchus, Cooperia, Oesophagostomum and Trichostrongylus. Season, farm and age of the animals had a significant (p<0.05) influence on the intensity of infection with strongyles, liver flukes and coccidia, whereas the sex of the animals had no significant (p>0.05) effect on the prevalence or intensity of infections. A higher intensity of infection with strongyles and coccidia was found in the wet season than in the dry season (p<0.05). The age-specific intensity was in the following order: for strongyles, immature animals of 6–12 months of age had the highest egg counts, followed by young calves and adults. Calves had significantly (p<0.05) higher oocyst counts than immatures or adults. Liver fluke egg counts did not differ significant (p>0.05) between immatures and adult cattle.     

A brief history of the prevention of infectious diseases by immunisations

Infectious diseases have always been a terrible scourge for humans. The appearance of these plagues, as they were called without distinction, was generally connected to various conditions: asters, climatic changes or religious reasons. The concept of contagious, and then infectious, diseases came slowly. Variolation, i.e. transmission of ‘virulent’ matter to induce a natural disease and the immunity against it, was brought from Constantinople to England by Lady Montague, in 1721. This ‘variolation’ technique was also often performed in veterinary medicine against diseases like sheep-pox or pleuropneumonia. As ‘vaccination’ is the term generally accepted for ‘immunisation’, variolation can be the word designating such a technique. The second period of the history of immunisation began, in 1880, with the studies of Pasteur and his collaborators. A great number of bacterial vaccines were developed: dead, live but attenuated or only parts of pathogens. The viruses were produced in animals, then in eggs and at last, in tissue cultures. Second generation vaccines appeared with genetic engineering: recombinant vaccines, vector vaccines, nucleic acids vaccines, and markers vaccines, among others. These novel technologies can permit the development of new ones and improve the quality of the vaccines already existing.     

Micronutrient Content of Certain Tropical Conventional and Unconventional Feed Resources of Southern India

The ash, silica and certain important micronutrients were estimated in conventional and unconventional feed and fodder resources available in Southern India. Commonly used dry roughages, such as paddy straw, ragi straw, maize kadbi/stalk, jowar kadbi/stalk, bajra stalk and wheat straw, were high in ash (9.9% +/- 0.77%) and silica (6.4% +/- 0.65%) and low in most of the other micronutrients, except iron, with paddy straw containing most silica (>9%). Cultivated non-leguminous (maize, jowar) and improved green crops (hybrid napier, guinea, green panic, NB-21, CO-1) were also high in ash (10.5% +/- 0.60% and 12.5% +/- 0.51%) but were moderate sources of P, Mg and Cu and good sources of Zn (98 +/- 13.8 ppm and 55 +/- 6.7 ppm). Leguminous green fodders (stylosanthus, lucerne, cow pea, soyabean) were excellent sources of Ca (1.9% +/- 0.16%), Mg (0.40% +/- 0.05%), Cu (30 +/- 5.2 ppm), Zn (121 +/- 14.7 ppm) and Fe (1234 +/- 166 ppm) and moderate sources of P. Mixed local grasses and weeds were high in silica (6.9% +/- 1.00%) but were good sources of Cu, Zn and Fe. Cereal grains (maize, wheat, rice, ragi) were low in ash (2.9% +/- 0.33%) and were relatively poor sources of Ca (0.22% +/- 0.03%), Mg (0.19% +/- 0.03%) and Cu (13 +/- 3.1 ppm). Pulses were low to medium sources of most minerals and good sources of Fe (1230 +/- 293 ppm). Oil seed cake/extractions (groundnut cake, cotton seed cake, soyabean meal, sunflower cake, safflower cake) and cereal by-products (rice polish, rice bran, wheat bran) were excellent sources of P (1.1% +/- 0.47% and 2.3% +/- 0.19%) and good sources of Zn (65 +/- 3.9 ppm and 66 +/- 10.7 ppm) and Fe (938 +/- 130 ppm and 662 +/- 126 ppm). Among the unconventional feeds screened, orange peel, sunflower heads, meat meal, rubber seed cake, spirulina algae and sea weeds contained plentiful Ca, Zn and Fe: tree leaves/top feeds (mulberry, erythrina, glyricidia, banana, subabul, groundnut haulms) were excellent sources of Ca (1.5% +/- 0.13%), Zn (120 +/- 22.9 ppm) and Fe (1033 +/- 133 ppm) but relatively poor sources of P. Soyabean husk, cocoa seed husk, rubber seed cake and meat meal were moderate to good sources of P (1.0% and 0.33%). The high Zn and Fe values of most feeds/fodders were probably due to soil contamination. This account of the micronutrient content of feed/fodder resources should help in strategic supplementation intended to alleviate local deficiencies.     

Bovine Mastitis in Selected Areas of Southern Ethiopia

A study on bovine mastitis, designed to determine the causal agents, prevalence of infection and impact of risk factors in three cattle breeds, was conducted in selected areas of southern Ethiopia. A total of 307 lactating and non-lactating cows, of which 162 were indigenous Zebu, 85 Jersey and 60 Holstein-Friesian, were examined by clinical examination and the California mastitis (CMT) test. Of these, 40.4% were positive by CMT and bacteriology for clinical or subclinical mastitis, with prevalence rates of 37.1% and 62.9%, respectively. Out of 1133 quarters examined, 212 (18.7%) were found to be infected, 83 (39.2%) clinically and 129 (60.8%) subclinically. The prevalence of mastitis was significantly higher in Holstein-Friesian than in indigenous Zebu, in non-lactating cows than in lactating cows, in the early lactation stage than in the mid-lactation stage, in cows with lesions and/or tick infestation on skin of udder and/or teats than in cows without this factor, and in the wet season than in the dry season. Mastitis increased with parity number (R = 0.9). Of 248 CMT and clinically positive udder quarter samples analysed microbiologically, 212 were culturally positive for known mastitis pathogens and 36 were negative. Of the 199 positive samples, Staphylococcus accounted for 39.2%, Streptococcus for 23.6%, coliforms for 14.1%, Micrococcus and Bacillus species for 8.0% each and Actinomyces or Arcanobacterium (Corynebacterium) for 7.0%. It was concluded that there was a high prevalence of clinical and subclinical mastitis, mainly caused by Staphylococcus aureus, Streptococcus agalactiae and Escherichia coli, in this study area.     

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。