体外法研究不同磷添加水平对奶牛瘤胃内pH 和挥发性脂肪酸的影响

采用体外法研究无机磷添加浓度对瘤胃发酵的影响。无机磷在培养液中设0、30、60、90、120、150、200、250、300、350 mg/L 10个水平。体外培养发酵48 h后终止培养,测定培养液的pH、总挥发性脂肪酸(VFA)。结果表明,不同无机磷添加水平对乙酸、丙酸、丁酸和总VFA产量影响显著(P＜0.05),无机磷添加水平为200 mg/L时,乙酸、丙酸、丁酸及总VFA产量最高,随后下降。瘤胃培养液pH随无机磷添加水平的增加而显著降低(P＜0.05),无机磷添加水平为200 mg/L时达到最小值5.65,随后又上升。在本试验条件下,添加无机磷明显促进瘤胃微生物对饲料养分的发酵,适宜添加水平为200 mg/L。     

不同饲养水平对肉羊瘤胃发酵参数pH值和挥发性脂肪酸的影响

为研究在同一种混合饲料下,不同饲养水平对肉羊瘤胃发酵参数pH值和挥发性脂肪酸浓度的影响,试验选取20只5月龄发育正常的健康肉用本地杂交绵羊.采用单因素完全随机分组设计,设4个处理组,每个处理5个重复.4个处理组分别为自由采食组、80％限饲组、60％限饲组、40％限饲组.结果表明,在采食相同饲料条件下,不同饲养水平对杂交肉羊瘤胃pH值,对瘤胃挥发性脂肪酸中乙酸、丙酸、丁酸、乙酸/丁酸比均略有影响.     

苜蓿皂苷对体外发酵pH值、氨氮及微生物蛋白浓度的影响

试验采用体外培养法研究了日粮中添加苜蓿皂苷对山羊瘤胃微生物发酵功能的影响.苜蓿皂苷的添加水平分别为底物基础的0%(对照组)、1%、2%、3%及4%.结果表明:日粮中添加苜蓿皂苷未对瘤胃液pH值和原虫蛋白浓度产生显著影响;添加苜蓿皂苷可提高氨氮浓度,但仅4%组增幅达显著水平(P＜0.05);4%组细菌蛋白浓度显著高于对照组(P＜0.01),其余各组间差异不显著(P＞0.05).结论:在本试验条件下,苜蓿皂苷添加量为0%～4%时均不影响瘤胃液pH值和原虫蛋白浓度.添加4%的皂苷是可显著提高NH3-N和细菌蛋白浓度.     

日粮中添加不同水平苜蓿皂甙对滩羊瘤胃挥发性脂肪酸的影响

本试验采用体外培养法研究了在以3∶7为精粗比的日粮条件下添加苜蓿皂甙对滩羊瘤胃挥发性脂肪酸的影响。苜蓿皂甙的添加水平为0(对照组)、0.5%(试验Ⅰ组)、1.0%(试验Ⅱ组)、2.0%(试验Ⅲ组)、3.0%(试验IV组)。结果表明:添加1.0%的苜蓿皂甙,瘤胃培养液的丙酸浓度呈现持续上升的趋势(P>0.05);添加量为3.0%时,其丙酸浓度分别在3、12和18 h时与对照组差异极显著(P<0.01);添加1.0%、3.0%的苜蓿皂甙,瘤胃培养液的乙酸浓度呈现持续上升的趋势;各添加水平下瘤胃培养液总的挥发性脂肪酸的浓度在一定时间内均呈现不同程度的上升趋势(P>0.05),但其乙酸/丙酸值却呈现下降趋势(P>0.05)。综观各添加水平苜蓿皂甙对滩羊瘤胃挥发性脂肪酸的影响结果,添加3.0%的苜蓿皂甙最为适宜。     

纳米铜对绵羊瘤胃体外发酵挥发性脂肪酸的影响

试验采用体外发酵法,研究在人工瘤胃液中添加不同浓度（0、50、100、150、200、400、800、1200、2400、4800μg/L）的纳米铜时,对绵羊瘤胃体外发酵挥发性脂肪酸的影响。试验共分10个处理组,每个处理组3个重复。结果表明：纳米铜在添加量为100-400μg/L时,乙酸浓度和总挥发性脂肪酸浓度都显著高于对照组和其他试验组（P〈0.05）。说明在体外发酵条件下添加适量的纳米铜对瘤胃微生物的发酵有促进作用。     

苜蓿皂苷对山羊瘤胃细菌发酵的影响

本试验旨在研究苜蓿皂苷对山羊瘤胃细菌发酵功能的影响。选择4只22月龄、体况良好、安装永久性瘤胃瘘管的徐淮山羊,晨饲后3 h采集瘤胃液,分离出细菌后,采用批次培养法进行体外发酵。试验分0%(对照组)、1%、2%及3%4个组,每组3个发酵瓶,每个发酵瓶为1个重复,体外厌氧培养24 h后,分别测定各处理组pH值、氨态氮浓度、微生物蛋白浓度及总挥发性脂肪酸含量。结果表明:添加1%~3%的苜蓿皂苷可以降低瘤胃细菌发酵液的pH值,提高总挥发性脂肪酸和氨态氮的浓度,但未对微生物蛋白浓度产生显著影响。     

体外法研究不同硒源及硒水平对瘤胃挥发性脂肪酸的影响

试验旨在利用体外厌氧发酵培养技术研究不同硒源及不同硒水平的添加对奶牛瘤胃挥发性脂肪酸(VFA)含量的影响。试验按照3×4完全随机试验设计,第一因素为硒源,即亚硒酸钠、硒代蛋氨酸和酵母硒3种,第二因素为硒添加量,即每毫升培养液中设0μg、0.1μg、0.2μg和0.3μg共4个添加水平,其中0μg/mL添加水平为对照组,共计10个处理组,每个处理组均进行3h、6h、9h、12h、24h和48h的体外批次培养,每个处理组设3个重复。试验结果表明,体外培养液中添加3种不同来源的硒对乙酸、丁酸、TVFA的影响组间差异显著(P<0.05),对丙酸、乙酸丙酸比影响较小(P>0.05),其中以添加酵母硒的乙酸、丙酸、丁酸、TVFA的效果最好,添加硒代蛋氨酸次之;体外培养液中添加0.3μg/mL硒,可显著提高乙酸、丁酸、TVFA的含量(P<0.05),对丙酸及乙酸丙酸比影响组间差异不显著,但均以0.3μg/mL硒组的效果较好。     

苎麻和苜蓿组合对体外瘤胃发酵参数的影响

本试验利用体外模拟瘤胃发酵评价苎麻和苜蓿组合对瘤胃发酵参数的影响,为畜牧业生产中合理使用苎麻提供数据参考。采用单因素试验设计,苎麻和苜蓿按照不同干物质比例（10∶90、20∶80、30∶70、40∶60、50∶50、60∶40、70∶30、80∶20和90∶10）组成9种发酵底物,选取3只装有永久性瘤胃瘘管的湘东黑山羊作为瘤胃液供体动物,模拟瘤胃发酵48 h。结果表明：每克底物的产气量和甲烷产量、降解每克底物的产气量和甲烷产量、产气速率、起始底物降解速率和干物质降解率随苎麻比例的增加均呈显著线性降低（P<0.05）;当苎麻比例≥30%时,干物质降解率显著降低（P<0.05）;当苎麻比例≥40%时,体外发酵产气量、产气速率和甲烷产量显著降低（P<0.05）。挥发性脂肪酸浓度、丙酸和丁酸比例随苎麻比例的增加呈显著线性降低（P<0.05）,而乙酸比例和乙丙比随苎麻比例的增加呈显著线性增加（P<0.05）;苎麻比例≥50%时,挥发性脂肪酸浓度显著降低（P<0.05）。综上所述,当苎麻比例≤20%时,对体外模拟瘤胃发酵和底物降解影响较小,并且对甲烷生成具有抑制...     

苜蓿皂苷对山羊瘤胃体外培养液纤维降解酶活及纤维降解率的影响

本试验研究了不同水平的苜蓿皂苷对生长山羊瘤胃培养液中纤维降解酶活及纤维降解率的影响。在山羊瘤胃培养液中分别添加0％、1％、2％、3％的苜蓿皂苷,进行体外培养。结果表明：添加量为1％时未对纤维素酶和木聚糖酶活性造成不利影响．但超过1％时则降低其活性．添加苜蓿皂苷未对内切葡聚糖酶活性和纤维二糖苷酶活性产生影响。1％-3％的苜蓿皂苷极显著地提高DM降解率,分别增加了14．0％、28．2％和25．8％。说明添加苜蓿皂苷未对瘤胃降解纤维素及半纤维素的能力产生不利影响．     

影响奶牛瘤胃pH值的因素

瘤胃液的pH值对奶牛的健康影响深远。正常瘤胃液的pH值在5．5～6．8之间变化,最佳pH值在6．0～6．3之间。瘤胃pH值在6．0时比较理想．在该状态下原虫和纤毛虫都可以迅速生长．从而产生大量挥发性脂肪酸,挥发性脂肪酸是奶牛所需能量的主要来源,影响瘤胃液pH值的因素如下：     

Gastrointestinal volatile fatty acid concentrations and pH in cats

OBJECTIVE: To measure volatile fatty acid (VFA) concentrations and pH in the gastrointestinal tracts of healthy adult cats fed a commercial dry cat food. ANIMALS: 14 cats. PROCEDURE: The gastrointestinal tracts were excised immediately after euthanasia and divided into 6 sections (stomach, duodenum, jejunum, ileum, proximal portion of the colon, and distal portion of the colon). Luminal contents were collected from each segment, pH was measured, and contents were centrifuged. The supernatant was analyzed for acetate, proprionate, butyrate, isobutyrate, valerate, and isovalerate concentrations by use of gas chromatography. RESULTS: Mean total VFA concentrations were lowest in the stomach (20 mmol/L); increased through the duodenum, jejunum, and ileum (30, 29, and 41 mmol/L, respectively); and were greatest in the proximal and distal portions of the colon (109 and 131 mmol/L, respectively). Estimated mean total VFA amounts were low (<600 micromol) throughout all segments of the gastrointestinal tract; pH values increased from the stomach through the ileum and subsequently decreased in the colon. CONCLUSIONS AND CLINICAL RELEVANCE: Total VFA concentrations in the colon were comparable to values reported for the forestomach of ruminants and large intestines of monogastric animals, whereas values in the small intestine were higher than reported for other species. Total VFA amounts were low, consistent with the short, nonvoluminous gastrointestinal tract of carnivores. Luminal pH varied throughout the gastrointestinal tract in a pattern similar to other monogastric animals. Volatile fatty acids probably contribute minimal metabolic energy in cats but may be important in the maintenance of local mucosal health.     

不同能量水平及玉米加工饲粮对瘤胃体外发酵参数的影响

利用体外产气法研究不同能量水平与不同加工方式玉米对瘤胃体外发酵参数的影响。试验以玉米秸秆为主要粗饲料来源设计精粗比为65∶35的等氮饲粮,选用玉米青贮与过瘤胃脂肪调整低、高能量水平,普通玉米与蒸汽压片玉米作为不同加工方式,采用2×2因子试验设计。结果表明,高能水平饲粮的理论最大产气量、48 h总产气量、干物质降解率均显著高于低能(P<0.05),普通玉米高能组的乙酸、丙酸含量显著高于低能组(P<0.05)。同一能量水平下,蒸汽压片处理组的48 h总产气量均显著高于普通玉米组(P<0.05);而低能条件下蒸汽压片组的总挥发酸、丙酸含量显著高于普通玉米组(P<0.05)。不同饲粮营养水平与体外产气参数相关性分析表明48 h总产气量与中性洗涤纤维(NDF)呈显著负相关(P<0.05),与中性洗涤可溶物(NDS)、非纤维性碳水化合物(NFC)和NDS/CP呈显著正相关(P<0.05)。因此,使用蒸汽压片方式处理玉米以及提高饲粮能量水平均可以显著增加体外发酵48 h总产气量;低能水平下,蒸汽压片玉米对改善瘤胃的发酵特性更为明显。     

Effects of fermented Yupingfeng on intramuscular fatty acids and ruminal microbiota in Qingyuan black goats

Our previous work has demonstrated that Yupingfeng, a Chinese herb medicine, considered as prebiotic showed beneficial properties in poultry health and disease prevention and regulated intestinal microbiota. The effects of Yupingfeng on fatty acids related to meat flavor and ruminal microbiota are not yet known in Qingyuan black goat. In this study, we supplemented fermented (FYP) and unfermented (UYP) Yupingfeng in different combinations to 90 goats. Compared with the normal control group, FYP and UYP significantly increased the concentration of palmitic acid, octadecanoic acid, and arachidonate acid (related to meat flavor) in the longissimus dorsi muscle (p < .05). In addition, the significant upregulation of peroxisome proliferator-activated receptor gamma (PPARγ) and fatty acid translocase (CD36) was observed in the FYP and UYP groups (p < .05). In addition, Firmicutes and Bacteroidetes were the most abundance in goat rumen. At the genus level, FYP and UYP significantly increased Ruminococcus related to fiber degradation, and Alistipes related to short-chain fatty acids production. In summary, Yupingfeng could improve fatty acids of goat meat, which is probably triggered by the increase of PPARγ and CD36, and microbial activity. Besides, FYP showed more beneficial effects than UYP, with increased flavor fatty acids and beneficial microbes.     

Effects of pH and fermentative substrate on ruminal metabolism of fatty acids during short‐term in vitro incubation

The ruminal biohydrogenation of c9,c12‐18:2 can be affected by the fibre/starch ratio of the diet and the ruminal pH. The objectives of this study were to examine independently in vitro the effects of fermentation substrate (hay vs. corn starch) and buffer pH (6 vs. 7) on the biohydrogenation of c9,c12‐18:2 carried out by grape seed oil, focusing on its t11 and t10 pathways, using 6‐h ruminal incubations. The experimental design was a 2 × 2 factorial arrangement. Fermentation substrate and pH affected the C18 fatty acid balance in incubated media, but few interactions were observed. Compared with starch, hay as the fermentation substrate favoured the production of 18:0 (×2.3), all trans‐18:1 isomers (×12.6) and CLA (×6.1), except c9,t11‐CLA, and the disappearance of unsaturated C18 fatty acids, but decreased the production of odd and branched chain fatty acids. Compared with pH 6 buffer, pH 7 buffer resulted in higher c9,c12‐18:2 disappearance and CLA production. For c9,t11‐CLA, an interaction was noticed between the two factors, leading to the highest production in cultures incubated on hay with the 7 pH buffer. Compared with starch, hay as fermentation substrate favoured the activity of t11 producers, which are fibrolytic bacteria, and the production of t10 isomers, possibly due to the presence of potential t10 producers in hay. Low pH resulted in a decreased t11 isomers production and in a slightly increased t10 isomers production, probably due to a modulation of enzymatic or bacterial activity.     

有机物进食量和外流速度对瘤胃VFA产生量及比例的影响

占日粮 70 %～ 80 %的碳水化合物和部分饲料蛋白质 ,在瘤胃中发酵产生挥发性脂肪酸(ＶＦＡ)、ＣＨ4、ＣＯ2 、ＡＴＰ等 ,为反刍家畜和瘤胃微生物维持和生长提供主要能量来源 ,因此评定ＶＦＡ中乙、丙、丁酸等比例及产生量 ,对于评定饲料营养价值及进一步提高反刍家畜能量转化效率具有重要意义。本试验旨在研究不同有机物进食量和外流速度对稻草 -玉米 -豆粕型日粮瘤胃发酵ＶＦＡ产生量及各挥发酸比例的影响。1　材料与方法1 1　试验动物和日粮　采用 3头体重在 50 0ｋｇ左右、安装有永久瘤胃瘘管的成年公牛。日粮采用ＡＲＣ(1 980 )肉牛饲…     

施氮对紫花苜蓿生长特性的影响

通过随机区组试验,研究了不施氮(N0)、施氮51.75kg/hm2(N1)和103.5kg/hm2(N2)3个氮水平对"甘农3号"紫花苜蓿生长第1年及第2年产量和再生性能的影响。结果表明:"甘农3号"紫花苜蓿生长第2年产量显著高于第1年,在N2处理下两年干草产量均最高,第1年为14 717kg/hm2,第2年为31 092kg/hm2;从株高和再生速度看,两年均以处理N2下紫花苜蓿的再生性能最强,并且第2年的明显优于第1年。综上,试验区"甘农3号"紫花苜蓿在N2处理下再生性能最好,株高和产量达最高,且两年均能进行4次刈割。     

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.     

Effect of fats and fatty acid combinations on ruminal fermentation in semi-continuous in vitro cultures

Four in vitro trials were conducted to determine how ruminal fermentation is affected by source of fat, level of fat, and combinations of fatty acids. Trials I and II examined how volatile fatty acids (VFA) were changed by three sources of fat (blended animal-vegetable fat, corn oil and tallow fatty acids) each added to a hay substrate at six levels (0, 2, 4, 6, 8 and 10%). Increasing blended fat caused no changes in VFA levels except to decrease butyric acid from 12.1 to 9.9% of the total VFA (P less than .05). Corn oil and tallow fatty acids both increased propionic acid, causing the ratio of acetic to propionic acids (A/P) to decrease (P less than .01). Trial III tested different ratios of oleic/stearic and linoleic/stearic acids to determine if certain combinations were better for fermentation. There was no evidence of synergism among fatty acids since increasing the ratio of unsaturates steadily reduced A/P. Trial IV was designed to determine how changes in VFA levels reflect changes in fiber digestibility of substrates containing added fat. Volatile fatty acids having significant regressions with fiber digestibility were acetic acid (r = .648), propionic acid (r = -.670), total VFA concentration (r = .742) and A/P (r = .831). Results are interpreted to show that blended animal-vegetable fats are less toxic in the rumen than equal levels of other lipids, and the beneficial effects of blended fat cannot be attributed to a unique combination of fatty acids acting synergistically.