绵羊粪与瘤胃液作菌源对纤维体外消化的比较研究

本研究以绵羊粪和瘤胃液作菌源,测定了4类(豆科、禾本科、秸秆及青贮)、9种粗饲料及5个混合粗饲料组中的中性洗涤纤维(NDF)的体外消化率(IVNDFD),用两种菌源的可发酵纤维指数(FFI)对这些粗饲料的纤维品质进行了评定。按两种菌源的FFI的大小对所测定的粗饲料纤维品质进行的排序完全一致:青干草>玉米青贮>玉米秸>羊草>草地早熟禾>谷草>混粗C2>混粗C1>混粗D>苜蓿>沙打旺>苏丹草;并以两种菌源不能消化的NDF(unNDF)为预测因子,建立了预测绵羊干物质随意采食量(DMI)的模型,比较、分析发现两种模型等效。考虑到不需使用瘘管动物,建议在生产实践中使用以绵羊粪作菌源所不能消化的NDF(unNDF)为预测因子的DMI模型:DMI豆(g/d·kgw0。75)=43.43/unNDF(％DM);DMI禾(g/d·kgw0.75)=33.89/unNDF(％DM);DMI秸(g/d·kgw0.75)=23.84/unNDF(％DM):DMI贮(g/d·kgw0.75)=22.42/unNDF(％DM)。     

Influence of kanamycin on the rumen bacteria and ammonia production in supplemented sheep rumen liquor in vitro

Bacteriological studies were made with in vitro sheep ruminal fluids supplemented with synthetic fodder containing different amounts of kanamycin (0.125, 2.50, and 60 mg/ml), during anaerobic incubation at 38–39°C for 6 h.Changes in the bacterial population occurred in the presence of large amounts (60 mg/ml) of kanamycin, and the B₁-type strain of Eubacterium became predominant.The marked increase in the concentration of ammonia in the supplemented rumen liquor, obtained after anaerobic incubation with high dosages of this antibiotic, is discussed.     

果寡糖对生长绵羊瘤胃发酵功能(体外)的影响

采用批次培养的方法,研究了体外条件下日粮添加果寡糖对生长绵羊瘤胃发酵功能的影响。果寡糖的添加水平为0(对照组)、0.20%、0.40%、0.60%、0.80%及1.00%。结果表明,日粮添加果寡糖可以显著提高培养液中的挥发性脂肪酸(VFA)含量(P<0.05),当添加量在0.60%以上时,可以显著提高培养液中的微生物细菌蛋白质(BCP)含量(P<0.05),显著降低培养液中的NH3-N含量和培养残渣中的中性洗涤纤维(NDF)含量(P<0.05);在本试验所设添加范围内,1.0%的果寡糖对提高瘤胃发酵功能作用最优。研究初步证明,日粮添加果寡糖可以在一定程度上提高生长绵羊的瘤胃发酵功能。     

体外产气法研究不同钾水平日粮对绵羊瘤胃发酵的影响

<正>近年来通过调控瘤胃发酵来提高反刍动物饲料转化率及生产性能一直是反刍动物营养研究的重点之一。钾对瘤胃微生物的生长以及瘤胃发酵都是必需的,不同钾水平的日粮在很大程度上影响了瘤胃发酵模式及动物的生产性能。20世纪90年代初以来,体外产气法由于能够较好地模拟瘤胃中的发酵历程和     

体外法研究异麦芽寡糖对生长绵羊瘤胃发酵功能的影响

采用批次培养的方法,研究了体外条件下日粮添加异麦芽寡糖对生长绵羊瘤胃发酵功能的影响。异麦芽寡糖的添加水平分别为0%(对照组)、0.20%、0.40%、0.60%、0.80%、1.00%。结果表明,日粮添加异麦芽寡糖可以提高培养液中挥发性脂肪酸(VFA)含量,降低培养液中的氨氮(NH3-N)含量和培养残渣中中性洗涤纤维(NDF)含量,但对培养液中菌体蛋白(BCP)含量的影响不确定。研究初步证明,日粮添加异麦芽寡糖可以在一定程度上提高生长绵羊的瘤胃发酵功能。     

Effects of halogenated hydrocarbons on rumen microorganisms

Halogenated hydrocarbons such as polychlorinated biphenyls (PCB's), heptachlor (HEP), 1,1,1-trichloro-2,2-bis(p-chlorophenyl)-ethane (DDT), and pentachlorophenol (PCP) are environmental contaminants and, at times, can bioaccumulate in the food chain. Cattle have been contaminated in a variety of ways, but generally it is believed that they are only affected by high concentrations of the chemicals. Rumen microorganisms, however, may be affected at lower doses, thus possibly affecting the cow's growth and milk production. Polychlorinated biphenyls, HEP, DDT, and PCP were tested by a 1-stage in vitro fermentation procedure. Substrate utilization was determined by measuring percent dry matter disappearance. Four concentrations (0, 10, 50, and 100 ppm) were studied, and in vitro incubations were conducted for 24 and 48 hr. Samples were removed from 48-hr incubations to determine if the chlorinated hydrocarbons were metabolized during fermentation. Dry matter disappearance proved to be a reliable method to determine microbial activity in the presence of chemicals. Substrate dry matter disappearance for controls and all concentrations of PCB's, HEP, and DDT was approximately 50 and 80% at 24 and 48 hr, respectively. The PCP significantly (P less than 0.05) depressed the percent dry matter disappearance in 50- and 100-ppm cultures to 45 and 30% at 24 hr and 70 and 50% at 48 hr, respectively. Metabolic changes in the test chemicals were not detected by gas chromatographic analysis.     

Experimental myrotheciotoxicosis in sheep and calves

Hamster inoculation, medium inoculation and microscopical methods were used for the detection of Leptospira interrogans serovar pomona organisms in bovine urine. Urine samples were collected from both naturally and experimentally infected animals during the period when leptospiruria could be expected.

Inoculation into hamsters of 0.5 ml of urine from each of 14 samples resulted in 5 positives. The inoculation of 0.025 ml of the same sample into semi-solid EMJH medium gave 10 positives. From a cumulative total of 46 urine samples, 28 were positive using dark-ground microscopy of centrifuged urine deposits and 35 were positive using media inoculation. A cumulative total of 126 urine samples were examined, after centrifugation, under dark-ground microscopy and leptospirae were detected in 60.

Fluorouracil (100 mg/ml) proved to be beneficial for successful isolations in media, whereas neomycin (5 mg/ml) did not.     

Tremorgenic mycotoxins increase gastric smooth muscle activity of sheep reticulum and rumen in vitro

Reticulum and rumen strips (consisting of both muscle layers and the myenteric plexus) were superfused with Tyrode Ringer and their contractions recorded isometrically. The strips were subjected to exogenous acetylcholine and electrical field stimulation (EFS) resulting in contractions that could be blocked by atropine. Responses to the tremorgenic mycotoxin penitrem A and others thought to be involved in ryegrass staggers, paxilline and lolitrem B (10(-10)-10(-6)M), were compared with those of control vehicle (0.1% DMSO). The tremorgens were without effect on quiescent preparations. Penitrem A and paxilline enhanced spontaneously active preparations and the amplitude of contractions in response to EFS. Responses to paxilline had a shorter latency than to penitrem A. Responses of spontaneously active preparations were resistant to atropine. Penitrem A, but not paxilline, increased responses to exogenous acetylcholine. Lolitrem B (10(-6)M) increased responses to EFS, but many responses were equivocal, possibly due to the lower solubility of lolitrem B in aqueous solutions compared to the other tremorgens. The results show that these mycotoxins have peripheral excitatory effects on the reticulorumen and it is suggested that such activity in vivo may reflexly affect centrally derived cyclical contractions.     

利用体外培养法研究奶牛瘤胃中奇链支链脂肪酸与微生物菌群的相关性

以纯碳水化合物为体外发酵底物,旨在探讨奶牛瘤胃中奇链支链脂肪酸含量与微生物菌群相对丰度的相关关系。试验选取3头安装永久性瘤胃瘘管的荷斯坦奶牛作为瘤胃液供体,以不同比例的纤维素(F)和淀粉(S)为培养底物(F∶S=0∶100,25∶75,50∶50,75∶25,100∶0)进行体外发酵。于体外发酵6,12,18,24 h采集发酵液并测定奇数和支链脂肪酸含量和微生物菌群相对丰度。结果显示:瘤胃液中奇数直链脂肪酸占总OBCFA的比例最大,且C15及其异构体所占的比例大于C17及其异构体的比例;F∶S对iso C15、anteiso C15、C15、iso C16、iso C17、anteiso C17和C17含量均有显著影响(P<0.05)。白色瘤胃球菌、黄色瘤胃球菌、溶纤维丁酸弧菌、嗜淀粉瘤胃杆菌和牛链球菌相对丰度受F∶S影响(P<0.05)。此外,白色瘤胃球菌和黄色瘤胃球菌的种群数量与iso C15和C15含量正相关(r=0.25～0.70,P<0.05),与iso C16和anteiso C17负相关(r=-0.28～-0.38,P<0.05);而嗜淀粉瘤胃杆菌与iso C15和C15含量负相关(r=-0.26～-0.43,P<0.05),与iso C16和anteiso C17正相关(r=-0.26～0.35,P<0.05);溶纤维丁酸弧菌的种群数量与iso C15、anteiso C15、iso C16、iso C17、anteiso C17和C17呈负相关(r=-0.35～-0.57,P<0.05);而牛链球菌与iso C15、anteiso C15、iso C16、iso C17、anteiso C17和C17呈正相关(r=0.34～0.43,P<0.05);反刍兽新月单胞菌与C15含量正相关(r=0.31,P<0.05),与anteiso C17负相关(r=-0.26,P<0.05)。由此可见,碳水化合物结构能显著影响瘤胃奇链支链脂肪酸的含量,以及纤维分解菌和淀粉分解菌的菌群丰度,并且奇链支链脂肪酸与瘤胃微生物存在相关性,因而可以间接反映细菌种群变化情况。     

Effect of wheat processing on rumen characteristics and rumen parameters in Holstein‐Friesian calves

In this experiment, effect of wheat processing on rumen conditions and development were investigated. Fifty‐six neonatal Holstein‐Friesian calves (22 male and 34 female) were fed calf starters and post‐weaning diets containing 35 (pre‐weaning) and 21.90% (post‐weaning) popped wheat (PW), steam‐flaked wheat (SFW), dry‐rolled wheat (DRW) or ground wheat (GW) till 12 weeks of age. Calves were weaned at the end of 9th week, and a post‐weaning‐specific starter diets were fed for 1 month. Rumen liquor was analysed in days 30, 60 and 90 of the experiment to determine volatile fatty acids (VFA), pH and ammonia nitrogen concentrations. Twelve male calves (three calves/treatment) were slaughtered, and digestive tract was emptied. Forestomach empty weight and rumen parameters were assessed. Results indicated that calves received PW had the highest total VFA, acetate, propionate, butyrate, ammonia nitrogen, rumen wall thickness, papilla width and density. Calves fed DRW experienced the lowest rumen pH throughout the experiment probably because high proportion of fine particles in GW. Calves consuming PW apparently had more functional rumen in comparison with other groups.     

In vitro transport of amino acids across the rumen mucosa in sheep]

Transfer of six amino acids through rumen epithelium of sheep has been studied on mucous and serous sides. Amino acids were classified into two groups: 1. lysine-arginine-glutamic acid, 2. glycine-alanine-leucine. The transfer of amino acids in triads was measured after 60 min. incubation. To determine amino acids transfer through rumen epithelium, three concentrations of amino acids were used: 1500: 150 and 15 mumol per 50 ml. In the first group of amino acids, the highest transfer of arginine was found in comparison with lysine and glutamic acid in all concentrations. The lowest transfer was found in glutamic acid. It follows from this that initial concentration of amino acids in the first group had no effect on amino acids transfer as far as the transfer of amino acids was as follows in all concentrations: arginine greater than lysine greater than glutamic acid. On the other hand, the composition of amino acids and initial concentration of amino acids in the second group exhibited the marked dependence on the transport of amino acids. The transfer of amino acids at the concentration of 1500 mumol per 50 ml was as follows: the passage of amino acids was the highest while this was lowest in alanine and leucine, at the concentration 150 mumol per 50 ml the highest transfer was found in alanine, it was lower in glycine and lowest in leucine and at the concentration 15 mumol per 50 ml the transfer of glycine was highest, lower in leucine and lowest in alanine.(ABSTRACT TRUNCATED AT 250 WORDS)