赖氨酸铜对西门塔尔牛瘤胃发酵及尿嘌呤衍生物的影响

选用4头装有永久性瘤胃瘘管的西门塔尔牛阉牛,采用4×4拉丁方设计,研究赖氨酸铜(0、8、16和24mg/kg)对瘤胃发酵和尿嘌呤衍生物的影响。结果表明:瘤胃pH值和VFA无显著差异(P>0.05);24mg/kg组NH3浓度高于对照(P<0.05),乙酸/丙酸低于对照组(P<0.05),玉米秸秆DM、OM、NDF和ADF有效降解率低于对照组和其他处理组(P<0.05),豆粕DM、OM和CP瘤胃有效降解率低于对照组(P<0.05)。24mg/kg组尿囊素、尿嘌呤衍生物和微生物蛋白低于对照和8mg/kg组(P<0.05)。赖氨酸铜添加量以8mg/kg为宜,兼顾基础日粮含铜量,建议日粮铜水平为11.25mg/kg。     

包被硒对西门塔尔牛瘤胃发酵和尿嘌呤衍生物的影响

选用4头装有永久性瘤胃瘘管的西门塔尔阉牛,采用4×4拉丁方设计,研究日粮中添加包被硒(0、0.3、0.6、0.9mg/kg)对瘤胃发酵和尿嘌呤衍生物的影响。结果表明:添加包被硒瘤胃中pH值、VFA、乙酸/丙酸比值均无显著差异(P>0.05);瘤胃氨态氮浓度显著降低(P<0.05);玉米秸秆DM、OM、ADF和NDF有效降解率提高;0.6mg/kg和0.9mg/kg组豆粕DM、OM和CP有效降解率显著高于对照组(P<0.05);0.6mg/kg组和0.9mg/kg组尿囊素、PD显著高于对照组和0.3mg/kg组(P<0.05)。兼顾基础日粮含硒量以及考虑硒的安全剂量,建议以包被硒为硒源时日粮硒添加水平为0.60mg/kg(以干物质计)。     

硫酸铜对西门塔尔牛瘤胃发酵及尿嘌呤衍生物的影响

选用4头体重420 kg、年龄2.5岁、装有永久性瘤胃瘘管的西门塔尔牛阉牛,采用4×4拉丁方设计,对照组饲喂基础日粮,处理组在基础日粮基础上添加硫酸铜,处理1,2和3组分别加硫酸铜31,62和93 mg/kg,研究硫酸铜对瘤胃发酵和尿嘌呤衍生物的影响。结果表明,瘤胃液pH值和挥发性脂肪酸浓度无显著差异(P>0.05);93mg/kg组氨态氮浓度显著升高,而乙酸/丙酸显著降低(P<0.05)。93 mg/kg组玉米秸秆和豆粕瘤胃有效降解率显著降低(P<0.05),尿酸无显著变化。93 mg/kg组尿囊素、尿嘌呤衍生物和微生物蛋白质显著低于对照和31mg/kg组(P<0.05)。表明添加93 mg/kg的硫酸铜影响瘤胃发酵,以硫酸铜为铜源时添加量以31~62 mg/kg为宜。     

包被铜对西门塔尔牛瘤胃营养物质降解率的影响

选用4头体重420 kg、2.5岁装有永久性瘤胃瘘管的中国西门塔尔牛,采用4×4拉丁方设计,研究包被铜(0、8、16和24 mg/kg)对瘤胃营养物质降解率的影响.结果表明:包被铜对瘤胃玉米秸秆和豆粕营养物质有效降解率影响均不显著(P＞0.05);根据试验结果推断包被铜可安全通过瘤胃,避免了铜对瘤胃微生物的影响.     

硒酵母对西门塔尔牛瘤胃发酵及尿嘌呤衍生物的影响

本试验旨在研究硒酵母对瘤胃发酵及尿嘌呤衍生物浓度的影响。选用8头体重(430±20)kg,年龄2.5岁,装有永久性瘤胃瘘管的中国西门塔尔牛阉牛,采用4×4重复拉丁方设计,以硒酵母为硒源,分别在日粮中添加硒0、0.3、0.6和0.9 mg/kg。结果表明:试验各组瘤胃pH、乙酸、丁酸和总挥发性脂肪酸差异不显著(P>0.05);处理组较对照组丙酸显著提高,而乙酸/丙酸比例和NH3-N浓度显著降低(P<0.05),0.6 mg/kg组NH3-N浓度显著低于0.3和0.9 mg/kg组;0.6 mg/kg组豆粕干物质、粗蛋白质有效降解率显著高于对照及其他处理组(P<0.05);0.6 mg/kg组玉米秸秆干物质、中性洗涤纤维有效降解率显著高于对照组和0.9 mg/kg组(P<0.05)。处理组尿嘌呤衍生物和微生物氮显著增加(P<0.05),0.6 mg/kg组显著高于0.3和0.9 mg/kg组(P<0.05)。硒酵母显著促进瘤胃代谢和提高尿嘌呤衍生物浓度,适宜添加水平为0.6 mg/kg。     

富铜酵母对西门塔尔牛阉牛瘤胃发酵及尿嘌呤衍生物的影响

本文旨在研究富铜酵母对瘤胃发酵和尿嘌呤衍生物浓度的影响.选用4头体重(420±15.2)kg、年龄2.5岁、装有永久性瘤胃瘘管的中国西门塔尔牛阉牛,采用4×4拉丁方设计,对照组饲喂基础日粮,处理1,2、3组分别在基础日粮干物质基础七添加富铜酵母(含铜10%)80、160和240 mg/kg.结果表明:瘤胃pH和挥发性脂肪酸(VFA)无显著差异(P>0.05);160和240 mg/kg组氨态氮(NH3-N)浓度显著低于对照组和80 mg/kg组(P<0.05),240 mg/kg组乙酸/丙酸比例低于对照组和80 mg/kg组(P<0.05).玉米秸秆和豆粕的干物质(DM)以及有机物(OM)有效降解率无显著差异,240 mg/kg组玉米秸秆中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)有效降解率显著降低(P<0.05),160和240 mg/kg组豆粕粗蛋白质(CP)有效降解率显著降低(P＜0.05).尿酸含量无显著变化,80和160 mg/kg组尿囊素和尿嘌呤衍生物含量显著高于对照组和240 mg/kg组(P<0.05).在本试验条件下,富铜酵母添加量在每千克干物质80～160 mg时效果较好;考虑在不同生产条件下,基础日粮中的铜水平有所不同,建议在以富铜酵母为日粮铜源时,日粮铜水平不可超过每千克干物质13.87 mg.     

包被铜对西门塔尔牛瘤胃pH、VFA和氨态氮的影响

选用4头420±12kg体重,2.5岁装有永久性瘤胃瘘管的中国西门塔尔牛,采用4×4拉丁方设计,研究包被铜(0、8、16和24mgCu/kg)对瘤胃pH、VFA和氨态氮的影响。结果表明:日粮添加包被铜对瘤胃pH、NH3、乙酸、丁酸、丙酸、总挥发性脂肪酸和乙酸/丙酸比例无显著影响。根据试验结果推断包被铜可安全通过瘤胃,避免了铜对瘤胃微生物的影响。     

肉牛日粮补饲铜对瘤胃VFA浓度和尿中嘌呤衍生物排出量的影响

选3头装有永久性瘤胃瘘管的西门塔尔杂交肉牛,采用3×3拉丁方设计,研究日粮补饲无机铜(0、8和18mg/kgDM)对瘤胃VFA浓度和尿嘌呤衍生物排出量的影响。结果表明:日粮补饲铜对瘤胃VFA浓度和摩尔比例有明显影响(P<0.05),与对照组相比,18mg/kgDM的补饲明显提高乙酸的摩尔比,降低丙酸、丁酸的浓度(P<0.05),而日粮中铜的补饲对尿中嘌呤衍生物排出量没有显著影响(P>0.05),每千克日粮补饲18mg/kgDM无机铜可明显促进瘤胃的发酵。     

限饲对东北梅花鹿消化代谢及尿嘌呤衍生物排出量的影响

试验选取4只体况相近的3岁东北梅花鹿公鹿,采用4×4拉丁方设计,饲喂同一种日粮,分4个不同限饲水平A(2.5kg/d)、B(2.0kg/d)、C(1.5kg/d)、D(1.0kg/d),利用尿嘌呤衍生物法并结合消化代谢试验,测定限制饲喂条件下东北梅花鹿尿嘌呤衍生物组成及排出量,可消化干物质和可消化有机物进食量与尿嘌呤衍生物排出量(PD)的关系及各种营养物质消化率。试验结果表明:东北梅花鹿尿中嘌呤衍生物包括49%～56%尿囊素、35%～38%尿酸、6%～15%黄嘌呤和次黄嘌呤;限饲条件下,东北梅花鹿尿中嘌呤衍生物、肌酐酸排出量无显著性差异(P>0.05);可消化干物质DDM(Ir=0.8592,n=16,P<0.001)和可消化有机物DOMI(r=0.8605,n=16,P<0.001)与尿中嘌呤衍生物排出量(PD)均存在显著的线性正相关;限饲使可消化干物质、可消化有机物质进食量和粗蛋白消化率显著降低(P<0.05),使干物质、有机物质、中性洗涤纤维、酸性洗涤纤维及钙、磷表观消化率均显著降低(P<0.05);限饲对尿氮和粪氮排出量无显著性影响(P>0.05),而显著影响氮沉积量(P<0.05),且随饲喂量降低,氮沉积逐渐减少,当饲喂量降到D水平时,出现了氮的负平衡,表明氮的摄入量已不能满足梅花鹿维持需要,需要动用内源氮来满足自身维持需要。     

牦牛尿嘌呤衍生物排出量对皱胃注射酵母RNA水平的响应

本研究对3头牦牛施以皱胃瘘管手术,以酵母RNA为嘌呤碱基供体,连续注射4期,以期测定牦牛吸收嘌呤的回收率,为尿嘌呤衍生物估测牦牛瘤胃微生物氮产量的模型积累数据。 结果表明,牦牛皱胃连续注射酵母RNA可使尿囊素(564～1 426 μmol/kg BW^0.75)、总嘌呤衍生物(purine derivative, PD)排出量(629～1 507 μmol/kg BW^0.75)及尿囊素占总PD比例线性提高(0.90～0.95)(P<0.01);嘌呤碱基注射水平对尿酸、肌酐及尿氮排出量影响不显著(P>0.05)。回归分析发现,牦牛皱胃嘌呤注射量(X,mmol/d)与尿嘌呤衍生物排出量(Y,mmol/d) 间存在线性关系:Y=0.85X+33.02 (R²=0.96,P<0.001),牦牛吸收嘌呤在尿中的回收率为85%。     

Factors that limit maintenance of recombinant rumen bacterium in sheep rumen

Factors limiting the maintenance of recombinant ruminal bacterium in the rumen were evaluated in vitro , using batch culture prepared from rumen fluid of sheep. Butyrivibrio fibrisolvens expressing a foreign xylanase gene ( B. fibrisolvens NO4) was used as a tested recombinant that was selectable on an erythromycin-containing agar medium. The recombinant tended to reduce its level slowly in the rumen fluid of sheep on a high hay diet, while its initial decrease was more apparent in the rumen fluid of sheep on a high concentrate diet. Incubation with cell-free ruminal fluid revealed a significant decrease of inoculated recombinant, suggesting the presence of antibacterial factors limiting maintenance of the recombinant. In particular, during the first 12 h of incubation this inhibition was more notable in culture prepared from rumen fluid of sheep given the high concentrate diet. Autoclaving the cell-free rumen fluid inactivated the inhibition. Numbers of the recombinant for inoculation did not influence the final level of survived recombinant, that is, the initial depression was larger as more recombinant was inoculated. Subculturing with xylan before inoculation and/or direct addition of xylan to the batch culture did not improve survival of the recombinant. From these results it is suggested that the level of survived recombinant is limited to 10^2–4/mL of in vitro batch culture with restricted energy supply and that initial depression of the recombinant is mainly caused by the heat-sensitive antibacterial factors not associating with microbial cells in the rumen.     

Comparison of rumen bacteria distribution in original rumen digesta,rumen liquid and solid fractions in lactating Holstein cows

Background: Original rumen digesta, rumen liquid and solid fractions have been frequently used to assess the rumen bacterial community. However, bacterial profiles in rumen original digesta, liquid and solid fractions vary from each other and need to be better established.Methods: To compare bacterial profiles in each fraction, samples of rumen digesta from six cows fed either a high fiber diet(HFD) or a high energy diet(HED) were collected via rumen fistulas. Rumen digesta was then squeezed through four layers of cheesecloth to separate liquid and solid fractions. The bacterial profiles of rumen original digesta, liquid and solid fractions were analyzed with High-throughput sequencing technique.Results: Rumen bacterial diversity was mainly affected by diet and individual cow(P 0.05) rather than rumen fraction. Bias distributed bacteria were observed in solid and liquid fractions of rumen content using Venn diagram and LEf Se analysis. Fifteen out of 16 detected biomarkers(using LEf Se analysis) were found in liquid fraction, and these 15 biomarkers contributed the most to the bacterial differences among rumen content fractions.Conclusions: Similar results were found when using samples of original rumen digesta, rumen liquid or solid fractions to assess diversity of rumen bacteria; however, more attention should be draw onto bias distributed bacteria in different ruminal fractions, especially when liquid fraction has been used as a representative sample for rumen bacterial study.     

Effect of nisin and monensin on rumen fermentation in the artificial rumen

The objective of this study was to investigate the effect of nisin and monensin on rumen fermentation of diets containing hay and barley (80:20%) in artificial rumen (Rusitec system). The Rusitec system consisted of four fermentation vessels (V1, V2, V3, V4): V1 was without additives (control), V2 received daily 2 mg of nisin, V3 involved 5 mg of monensin and V4 combination of 2 mg of nisin with 5 mg of monensin. After an adaptation period (7 days), the fermentation parameters were determined for six consecutive days. Compared to control diet, the addition of nisin resulted in an increase (P < 0.05) of hemicellulose degradation, acetate, propionate (mmol.day-1) production and energetic efficiency of VFA (E), decrease of butyrate production. Nisin had no effect on dry matter (DM), organic matter (OM), cellulose and detergent fiber degradation, production of total gas, methane and efficiency of microbial synthesis. The addition of monensin resulted in an decrease of DM, OM (P < 0.05), cellulose, hemicellulose, detergent fiber degradation (P < 0.001), total gas, methane and ammonia nitrogen (NH3-N) production. Monensin also significantly decreased acetate, butyrate, L-lactate (mmol.day-1) production and it increased propionate production (P > 0.001) and efficiency of microbial synthesis. The combined effect of nisin and monensin in V4 was similar to the effect of monensin in V3 compared to control. Then, the effect of additive monensin was dominant over nisin. In conclusion, our results indicate that nisin was less effective than monensin on some fermentation parameters (important for the improvement of the efficiency of utilization of the diet by ruminants) in artificial rumen.     

日粮精粗比对瘤胃内环境及微生物区系影响的研究

瘤胃作为反刍动物体内的饲料加工厂,其内环境稳定和微生物区系的平衡影响着动物对饲料的利用,日粮精粗比的改变影响瘤胃内环境稳态以及微生物区系组成,从而影响反刍动物的生产效率。本文综述了日粮精粗比影响瘤胃pH、NH3-N浓度、VFA浓度和瘤胃微生物区系组成的研究进展,为在生产实践中提高反刍动物生产效率提供理论依据。     

西藏农区黄牛主要瘤胃微生物及瘤胃液物质特征值

通过测定牛瘤胃液中N源、可溶性糖含量,统计分类纤毛虫数量和改良纤维分解细菌选择性培养基等方法,发现瘤胃内 NH+1-N、NO-3-N、全N和可溶性糖处在一个动态变化过程,含量的高低取决于瘤胃内食糜的养分、食糜和瘤胃液在瘤胃中的排空时间,同时鉴定了西藏黄牛瘤胃液中12种不同属的纤毛虫、4个主要纤维素分解细菌和厌氧真菌的数量变化特点.结果表明,NH+4-N含量变化较小,在平均值(71.279 9±15.120 5)mg/L浮动;NO-3-N在AM 10:00达到最高值;全N在AM 8:00和16:00含量最高.通过试验改良的纤维素菌培养基能较好地培养瘤胃内4种细菌,为更进一步研究瘤胃内微生物提供了一条途径.     

过瘤胃蛋白质饲料保护技术研究进展

过瘤胃蛋白是反刍动物吸收氨基酸的重要来源,降低蛋白质在瘤胃内的降解率能提高动物的生产性能,改善氮的利用,增加氮的沉积,从而提高优质蛋白质饲料的利用率。国内外对过瘤胃蛋白做了大量的研究,包括各种化学方法、热处理方法和物理包被,以及最有推广应用价值的戊糖加热复合保护处理法。