不同有机物进食量和外流速度对瘤胃发酵及微生物蛋白合成效率的影响

采用2×2 随机因子试验设计研究持续动态瘤胃模拟装置(RST—Ⅱ) 不同有机物进食量(0MI)(27-67 g、36-74 g、46-00 g) 和瘤胃外流速度(0-02/h ,0-035/h,0-05/h) 对稻草—玉米—豆粕型日粮瘤胃发酵及微生物蛋白合成效率的影响。结果表明,RSI内pH 不受有机物进食量和外流速度影响;在低外流速度下各OMI组瘤胃内0 ～72h 干物质、有机物、粗蛋白、NDF、ADF降解率均高于高外流速度(P< 0-05)。随着0MI的增加,同一外流速度下日粮可发酵有机物产生VFA 量(TVFA/FOM,mmol/g)逐渐下降(P< 0-05);相同0MI组饲料降解氮转化为微生物氮的效率在外流速度为0-02/h 时显著高于高外流速度(P<0-05) 。     

不同有机物进食量和外流速度对瘤胃发酵及微生物蛋白合成效率的影响

采用2×2随机因子试验设计研究持续动态瘤胃模拟装置(RSI-Ⅱ)不同有机物进食量(OMI)(27．67g、36．74g、46．00g)和瘤胃外流速度(0．02/h、0．035/h、0．05/h)对稻草-玉米-豆粕型日粮瘤胃发酵及微生物蛋白合成效率的影响。结果表明,RSI内pH值不受有机物进食量和外流速度的影响;在低外流速度下各OMI组瘤胃内0～72h干物质、有机物、粗蛋白、NDF、ADF降解率均高于高外流速度(P＜0．05)。随着OMI的增加,同一外流速度下日粮可发酵有机物产生VFA量(TVFA/FOM,mmol/g)逐渐下降(P＜0．05);相同OMI组饲料降解氮转化为微生物氮的效率在外流速度为0．02h时显著高于高外流速度(P＜0．05)。     

阉牛不同日粮的纤维消化,瘤胃内VFA对甲烷产生量的影响

装有瘤胃和真胃瘘管的成年阉牛４头，体重（５００±５０）ｋｇ，采用４×４完全拉丁方试验设计，在呼吸代谢室内就不同日粮的纤维消化、瘤胃内ＶＦＡ对甲烷产生量的影响进行了研究。结果表明：（１）可消化中性洗涤纤维（ＤＮＤＦ）和可消化酸性洗涤纤维（ＤＡＤＦ）的甲烷产生量，在不同加工细度羊草之间（７．５ｍｍ，１５ｍｍ，３５ｍｍ和长草）无显著差异（Ｐ＞０．０５）。（２）不同精粗比日粮（０∶１００，２５∶７５，５０∶５０，７５∶２５）的ＮＤＦ或ＡＤＦ降解量（ｋｇ／ｄ）与甲烷产生量呈较高的线性正相关（ｒ＝０．８６８９或ｒ＝０．９７７５），乙酸、丙酸、乙酸＋丙酸产量（ｍｏｌ／ｄ）以及乙酸／丙酸与ＣＨ４产生量（Ｌ／ｄ）之间均存在较高的线性相关（ｒ依次为０．９６９１，－０．９６８３，０．９７８９，０．８８３３）。     

瘤胃灌注不同比例的混合VFA对肉牛瘤胃发酵、能量和氮代谢的研究

以装有瘤胃瘘管的肉牛（３９０±３０ｋｇ）饲喂全羊草的基础日粮,瘤胃灌注４种不同摩尔比例的混合ＶＦＡ（乙酸：丙酸：丁酸为７５∶１５∶１０,６５∶２５∶１０,５５∶３５∶１０和４５∶４５∶１０）,按４×４拉丁方试验设计测定了灌注后代谢产热率（ＨＰ／ＭＥ）,ＶＦＡ转化为体脂肪的效率（Ｋｆ）和可消化氮转化为沉积氮的效率。结果表明,随着灌注混合ＶＦＡ中丙酸比例超过２５％,ＨＰ／ＭＥ明显降低（Ｐ＜００５）,Ｋｆ值极显著地增加（Ｐ＜００１）;可消化氮转化为沉积氮的效率显著增加（Ｐ＜００５）;ＨＰ／ＭＥ与瘤胃中乙酸比例、Ｋｆ值与瘤胃液中丙酸比例均呈线性正相关。     

饲料通过梅花鹿瘤胃外流速度的研究

梅花鹿是我国珍贵的野生经济动物,属反刍动物。其采食的饲料种类与牛、羊有所不同,野生时以食嫩树枝叶为主,家养条件下则以嫩树枝叶和青贮饲料为主。本试验选用三头带有瘤胃瘘管体重约为130kg的三锯梅花鹿,测定了四种有代表性精、粗饲料(豆饼、玉米面、柞树叶、青贮玉米)的瘤胃外流速度。试验期每期15天,预试期10天,正试期5天。日粮能量水平为16317.6KJ/kg;蛋白质水平为17.08％;Ca、P含量分别为0.87％和0.47％。采用铬标记     

青粗饲料通过牛瘤胃外流速度的研究

用铬标记饲料的方法测定了不同细度、不同种类粗饲料通过瘤胃的部分外流速度 Kp。试验结果表明,标记饲料的细度明显影响 Kp 的测定结果。饲料颗粒越细,通过瘤胃的外流速度越快。对于粗饲料,测定 Kp 时标记粒度应在流出瘤胃的临界粒度1.19mm 以下才具有代表性。不同种类的粗饲料,其 Kp 值不同。羊草、高粱青贮和豆腐渣的 Kp 值分别为0.0314、0.0253、0.0399h~(-1)。     

复合脂肪酸和乳酸对奶牛瘤胃VFA和CH4的影响

将20头安装瘤胃瘘管的荷斯坦产奶牛随机分为对照组和试验Ⅰ～Ⅲ组,每组5头,对照组饲喂TMR,试验Ⅰ～Ⅲ组饲喂TMR分别加150．0g／（头·d）复合脂肪酸、乳酸和复合脂肪酸＋乳酸（1：1）,探讨复合脂肪酸和乳酸对奶牛瘤胃CH4释放量、VFA和NH3-N浓度及产奶性能的影响。结果显示,TMR加150．0g／（头·d）复合脂肪酸＋2L酸（1：1）,使奶牛瘤胃NH3-N和CH4释放量分别减少11．92％（P〈0．05）和21.35％（P〈0．01）,FCM、乳脂率和乳糖含量分别提高3．28％、5．12％和3．62％,瘤胃VFA明显增加,能够有效抑制奶牛对空气的CH4污染．显著提高奶牛的生态效益和经济效益。     

大蒜对肉牛瘤胃VFA及其瘤胃内饲料降解的影响

肉牛饲料中分别添加 3种剂量的大蒜 (5 0、10 0、15 0g 天·头 )及其活性物质大蒜素 (0 .2、0 .4、0 .6g 天·头 ) ,试验肉牛瘤胃TVFA、乙酸、丙酸浓度发生不同变化。对大蒜和大蒜素不同添加剂量与对应试验肉牛瘤胃TVFA和乙酸 丙酸变化间的多元回归模型求导后得出 ,大蒜和大蒜素在肉牛饲料中的适宜添加量分别为 75～ 94g 天·头和 0 .3～ 0 .4g 天·头。并将大蒜和大蒜素按 75g 天·头和 0 .3g 天·头添加量加入到肉牛饲料研究发现 :饲喂大蒜和大蒜素试验组玉米秸秆干物质和中性洗涤纤维的潜在降解率与对照组相比分别提高 11.2 1%、7.2 8%和 19.5 %、9.6 7% (P <0 .0 5 ) ;而对精饲料中粗蛋白潜在降解率无显著影响     

饲喂不同比例小叶章日粮对乳牛瘤胃内环境、VFA浓度和生产性能的影响

利用3头装有永久性瘤胃瘘管的荷斯坦奶牛,采用3×3拉丁方实验设计,测定适宜期收获的小叶章牧草占粗饲料不同比例时对奶牛瘤胃pH值、NH_3-N、VFA浓度和生产性能的影响。结果表明:饲喂100％、25％和50％比例小叶章日粮时,奶牛瘤胃内pH值分别为6．93、6．69和6．72;氨氮浓度分别为2．15～2．73 mol/L,2．19～2．77 mol/L和2．33～2．90 mol/L; TVFA浓度平均值分别为84．74 mmpl/L、83．75 mmol/L和85．86 mmol/L;平均日产奶量分别为15．31 kg、20．21 kg和17．62kg;平均乳脂率分别为3．98％、3．27％和3．46％。结果表明:当饲喂占日粮粗饲料25％的小叶章青干草时,奶牛瘤胃具有较好的内环境和发酵产物,奶牛具有较高的生产性能。     

不同营养水平对牦牛瘤胃内VFA的影响

应用气相色谱法,在维持型(略低于维持水平)、粗料型、精料型三种不同营养条件下测定了牦牛瘤胃内挥发性脂肪酸(VFA)的组成及含量。结果表明:维持组除丙酸及C_2/C_3比例极显著(P<0.01)低于粗料组外,其它无差异(P>0.05);精料组的总挥发性脂肪酸(TVFA)和乙酸高于粗料组(P<0.05),但C_2/C_3比例相同,二者属同一发酵类型。丙酸、丁酸含量高于其它动物是牦牛瘤胃代谢的特点。     

Rumen fermentation with special reference to volatile fatty acid production during reproduction. 1. Methods and results of volatile fatty acid levels and production rates in vitro

The target of the investigations was to register part of the synthesis performance in the rumen of ewes during the complete reproduction cycle. With the help of in-vitro experiments with artificial rumen the concentration and production rates of volatile fatty acids in the rumen fluid were measured. From the experiments the measured data of fertility-accentuated crossbreeding (experiment 1) and crossbreeding (experiment 2) ewes were contrasted. The average concentrations of volatile fatty acids in ewes are 95.4 m mol/l in experiment 1 and 109.2 m mol/l in experiment 2 during the early stage gestation, 121.4 m mol/l in experiment 1 and 99.8 m mol/l in experiment 2 in the last stage stage of gestation, 129.6 m mol/l in experiment 1 and 112.8 m mol/l in experiment 2 during lactation and 106.6 m mol/l in experiment 1 and 112.9 m mol/l in experiment 2 during the dry period. The production rates of volatile fatty acids calculated form their concentration amount to 4.8 m mol/l X h in experiment 1 and 2.6 m mol/l X h in experiment 2 in the early stage of gestation, 3.5 m mol/l X h in experiment 1 and 3.1 m mol/l X h in experiment 2 in the last stage of gestation, 3.2 m mol/l X h in experiment 1 and 2.7 m mol/l X h in experiment 2 during lactation and 3.7 m mol/l X h in experiment 1 and 2.9 m mol/l X h in experiment 2 in the dry period. The correlation between the concentration and the production rate of volatile fatty acids is not significantly negative in either of the ewe experiments. The scattering of the individual values is wide so that the individual influence of the test animals as well as the influence of the in-vitro method used permit the conclusion that a significant statement on the influence of the genotype and the stage of reproduction on the production rates cannot be made.     

脂肪酸添加剂对奶牛瘤胃挥发性脂肪酸和甲烷的影响

21头安装瘤胃瘘管的荷斯坦产奶牛随机分为对照组和试验Ⅰ~Ⅵ组,每组3头,对照组饲喂全混日粮(TMR),试验Ⅰ~Ⅵ组每天饲喂TMR加50.0 g、100.0 g、150.0 g、200.0 g、250.0 g、300.0 g/头复合脂肪酸日粮,主要探讨复合脂肪酸对奶牛瘤胃甲烷(CH4)产量、挥发性脂肪酸(VFA)、氨氮(NH3-N)浓度和pH值及产奶性能的影响。结果,TMR中每天添加150.0~200.0 g/头复合脂肪酸,明显(P<0.05)提高奶牛乳脂率和瘤胃乙酸浓度,显著(P<0.05)降低奶牛的CH4释放量、CH4能/GE值和瘤胃NH3-N浓度,对奶牛的标准乳(FCM)、乳干物质、乳蛋白和乳糖均有提高趋势,能有效地提高奶牛的经济效益和生态效益。     

Effects of rare earth element lanthanum on rumen methane and volatile fatty acid production and microbial flora in vitro

The objectives of the trial were to study the effects of rare earth element (REE) lanthanum (La) on the in vitro rumen methane (CH₄) and volatile fatty acid (VFA) production and the microbial flora of feeds. Four feed mixtures with different levels of neutral detergent fibre (NDF), that is 20.0% (I), 31.0% (II), 41.9% (III) and 52.7% (IV), were formulated as substrates. Five levels of LaCl₃, that is 0, 0.4, 0.6, 0.8 and 1.0 mmol/kg dry matter (DM), were added to the feed mixtures, respectively, as experimental treatments in a two‐factor 5 × 4 randomized design. The in vitro incubation lasted for 24 h. The results showed that supplementing LaCl₃ increased the total gas (p < 0.001) production and tended to increase the total VFA production (p = 0.072) and decreased the CH₄ production (p = 0.001) and the ratios of acetate/propionate (p = 0.019) and CH₄/total VFA (p < 0.001). Interactions between LaCl₃ and NDF were significant in total gas production (p = 0.030) and tended to be significant in CH₄ production (p = 0.071). Supplementing LaCl₃ at the level of 0.8 mmol/g DM decreased the relative abundance of methanogens and protozoa in the total bacterial 16S rDNA analysed using the real‐time PCR (p < 0.0001), increased F. succinogenes (p = 0.0003) and decreased R. flavefaciens (p < 0.0001) whereas did not affect R. albus and anaerobic fungi (p > 0.05). It was concluded that LaCl₃ decreased the CH₄ production without negatively affecting feed digestion through manipulating rumen microbial flora when feed mixtures with different levels of NDF were used as substrates.     

Measurement of volatile fatty acid production rates in sheep given roughage

Measurement of the irreversible loss rate (ILR) of acetate, propionate and butyrate by radioisotope dilution of the respective tracers in sheep offered chopped dried grass from continuous belt type feeders gave 'plateau samples', the specific radioactivity of which had unacceptably high variance (coefficient of variation [cv] of the five or six samples taken from any one animal over the last four hours of 10 hours infusion ranged from 16 to 57 per cent). In an experiment which attempted to identify the source of this variability the distribution of the liquid phase marker 51Cr EDTA into different areas of the rumen was examined during its administration either in liquid form or impregnated on paper. The paper provided better mixing but incurred considerable spillage problems which would be unacceptable where calculations of ILR were required. Radiographic observations were made to examine the mixing of radio-opaque liquid and solid phase markers in the rumen. A better mixing of both was achieved with intermittent than continuous feeding. When 1-14C- and 2-14C-labelled acetate were each infused into the rumen of four sheep given two levels of chopped dried grass by means of hourly feeders, samples of rumen liquor gave much lower variability of the mean plateau specific radioactivity values than was obtained in experiment 1 (cv less than 15 per cent in all but one sheep). The ILRs of acetate and the transfer quotients of carbon from acetate to butyrate obtained using 1-14C- and 2-14C-labelled acetate were similar.(ABSTRACT TRUNCATED AT 250 WORDS)     

A note on the relationship between the production rates of volatile fatty acids and their concentration,digestible organic matter and total digestible nutrient intake in buffalo calves

Volatile fatty acid (VFA) production rates were measured by isotope dilution technique in the rumen of buffalo calves fed on wheat straw plus concentrate, green maize, cow pea and berseem. Correlations derived between the VFA production rates and their concentration and DOM were significant except in animals fed on cow pea. The VFA production rates were also significantly correlated with the TDN intake in all the four feeds tested.The regression equations obtained for the four feeds were different, which suggested that VFA production may vary with the quantity and quality of feed digested. These experiments suggest the use of different regression equations for different feeds.     

Studies on rumen fermentation with special reference to the volatile fatty acid production rate in ewes during reproduction. 2. Production rate of volatile fatty acids and rumen volume

Methods and results of the measuring of the rumen volume and the passage rate as well as the dependence of the production of volatile fatty acids on the parameters mentioned are described. The correlative relations between rumen volume on the one hand and feed passage on the other hand to the production quotas are investigated. Passage rates and rumen volumes were determined with the help of the isotope dilution method. In the course of reproduction rumen volumes of 7.81, 6.41, 8.91, 7.11 in experiment 1 and 5.41, 5.81, 9.51 and 4.71 in experiment 2 were measured in the sequence early stage of gestation, late stage of gestation, lactation and the period between pregnancies. The average total production of volatile fatty acids within 12 hours amounted to 475 mmol, 265 mmol, 313 mmol and 351 mmol in experiment 1 and 155 mmol, 175 mmol, 271 mmol and 144 mmol in experiment 2 in the same sequence. The average passage duration of the feed through the digestive tract of the ewes was 32.4 h in experiment 1 and 33.6 h in experiment 2. The relatively high feed intake of the ewes resulted in a short passage duration and could be a cause of the low production quotas of the volatile fatty acids.     

利用体外法研究不同水平苜蓿皂苷对山羊瘤胃内pH值和挥发性脂肪酸的影响

试验通过体外培养法研究日粮中添加苜蓿皂苷对山羊瘤胃微生物发酵功能的影响。试验分5组,各组苜蓿皂苷的添加水平分别为基础底物(2g)的0(对照组)、1%、2%、3%及4%,每组3个重复,体外厌氧培养24h,并分别测定各处理组pH值和挥发性脂肪酸含量。结果表明:添加苜蓿皂苷未对培养液pH值产生显著影响;添加1%～4%的苜蓿皂苷可极显著提高培养液中乙酸、丙酸浓度(P<0.01);添加1%的苜蓿皂苷可极显著提高丁酸浓度(P<0.01),2%组可显著提高丁酸浓度(P<0.05);各苜蓿皂苷添加组中乙酸/丙酸的比例均极显著低于对照组(P<0.01)。结论:本试验条件下,添加1%～4%的苜蓿皂苷可改善瘤胃发酵模式,提高反刍动物对发酵终产物的利用率,且添加1%的苜蓿皂苷效果最佳。     

Effects of high iron and sulfate ion concentrations on dry matter digestion and volatile fatty acid production by ruminal microorganisms.

The inhibitory effects of iron- and sulfate-containing compounds on the in vitro digestion of a balanced forage diet by mixed populations of ruminal microorganisms were examined in batch cultures. Compounds containing ferrous and ferric cations consistently inhibited DM digestion by up to 36% when added Fe concentrations in cultures were between 100 and 1,000 mg/L. Increased sulfate concentrations of up to 200 mg/L or chloride concentrations of up to 635 mg/L were not associated with decreased DM digestion. Ammonium sulfate additions that provided 200 mg/L of added sulfur increased (P less than .05) digestibility by 10%. Sulfate-containing iron salts tended to be less inhibitory than chloride salts and were associated with increased gas production during digestion. Ferric chloride inhibited (P less than .05) microbial activities at lower concentrations than ferrous chloride. Data suggest that excessive iron supplementation or contamination of feeds with iron-containing pollutants may decrease microbial activities in the rumen.