灌注果寡糖对生长绵羊瘤胃发酵功能的影响

试验采用营养灌注技术研究了果寡糖对生长绵羊瘤胃发酵功能的影响.试验选取6只安装有永久性瘤胃瘘管的内蒙古半细毛羯羊,随机分为两组,试验1组灌注1.00%果寡糖,试验2组灌注2.00%果寡糖.结果表明:灌注果寡糖可以显著(P＜0.05)降低试羊的瘤胃液相pH值和瘤胃内的氨态氮浓度,显著提高(P＜0.05)瘤胃内的挥发性脂肪酸(VFA)含量和瘤胃细菌蛋白(BCP)含量.两个灌注水平都可以提高生长绵羊的瘤胃发酵功能,但2.00%的灌注水平仅在瘤胃氨态氮浓度的降幅方面比1.00%的灌注水平显著增大(P＜0.05),在对瘤胃液相pH值、VFA含量和BCP含量的影响方面两个灌注水平没有显著差异(P＞0.05).     

日粮中不同棉籽水平对肉牛瘤胃发酵的影响

以 3头平均体重 (6 0 0± 10 0 )kg、装有永久性瘤胃瘘管的 7岁西杂阉牛为研究对象 ,实验采用 3× 3拉丁方设计 ,研究日粮中不同棉籽水平对肉牛瘤胃机能的影响作用 ,为肉牛日粮中适宜的整粒棉籽添加水平提供参考。 3种试验日粮分别表示为 :⑴对照组 :饲喂基础日粮 ;⑵中棉籽组 :添加 13%棉籽 ;⑶高棉籽组 :添加 2 5 %棉籽。研究结果显示 ,与对照组相比 ,中棉籽组、高棉籽组在一个周期内的pH平均值略有降低 (- 0 .11、- 0 .0 9)。各处理组在同一个时间点的pH值变化不显著 (P >0 .0 5 )。中棉籽组的氨氮浓度平均值最高 (7.0 1mmol/L) ;与对照组相比 ,中棉籽组的氨氮浓度平均值上升 0 .2 9mmol/L ,高棉籽组的氨氮浓度平均值下降 0 .0 7mmol/L。与对照组相比 ,中棉籽组、高棉籽组的总挥发性脂肪酸浓度分别提高 7.4 %、3.5 % ,乙酸和丙酸浓度平均值也较对照组有所提高 ;而丁酸浓度和乙酸 /丙酸值比对照组低。 3种日粮间的乙酸 /丙酸的平均值存在着显著性差异 (P <0 .0 5 ) ,其平均值分别为 4 .4 9、4 .35、4 .0 5。     

尿素复合舔块对绵羊瘤胃微生物蛋白质合成的影响

本研究将４只绵羊随机分为２组，试验组在饲喂基础日粮的基础上，每天每只着补饲５０ｇ舔块，探讨了该舔块对绵间瘤胃微生物蛋白质合成的影响。结果表明：补饲复合舔块，微生物氮产量与微生物氮的合成效率分别比对照组增加了１６．６％与１５．１％，提高了瘤胃微生物蛋白质的产量与合成效率。     

不同水平大豆油对山羊瘤胃体外发酵参数的影响

通过体外培养研究不同水平大豆油(2%、4%、6%、8%,依次为l、2、3和4组)在精粗比为30:70(偏粗型)日粮条件下对总产气量、甲烷产量、pH值和纤维降解率的影响.结果表明:随着大豆油添加水平的提高,总产气量、甲烷产量逐渐降低,且各试验组明显低于对照组.试验组pH值与对照组相比,2组除个别时间点(6、10和24 h)外,差异均显著(P<0.05);3组除10 h外,差异显著或极显著(P<0.05,P<0.01);4组除10 h外,差异均极显著(P<0.01).培养24 h后,4组对纤维降解率的抑制潜力最大(P<0.01),其次是3组(P<0.05).大豆油的最适添加水平为4%.     

体外产气法研究壳聚糖对山羊瘤胃发酵的影响

应用体外产气法模拟瘤胃发酵,通过测定24 h体外累计产气量、中性洗涤纤维(NDF)的降解率和细菌氮含量,研究添加不同水平壳聚糖对山羊瘤胃发酵的影响.结果表明,壳聚糖可以促进瘤胃发酵,使微生物蛋白合成和纤维分解增加.在本试验条件下,山羊日粮中壳聚糖的最适添加水平为0.09%～0.12%.     

苹果酸对山羊瘤胃纤维降解率及发酵类型的影响

以4头装有永久性瘤胃瘘管的本地山羊为试验动物,采用4×4拉丁方设计,研究苹果酸(0、5、10和15 g/d)对山羊瘤胃纤维降解率及瘤胃发酵类型的影响。结果表明,日粮中添加苹果酸能够显著提高瘤胃内中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)的降解率(P<0.05);瘤胃液中乙酸与丙酸比值显著降低(P<0.05),改变了瘤胃发酵类型;氨态氮浓度显著降低(P<0.05),促进了瘤胃微生物对氨、氮的利用。     

不同油料籽实对奶牛瘤胃代谢及养分表观消化率的影响

以3头年龄相同、平均体重为(650±20)kg,处于同一泌乳期的装有永久性瘤胃瘘管的荷斯坦奶牛为研究对象,试验采用3×3拉丁方设计,研究探讨日粮中添加不同的油料籽实(日粮脂肪含量均在6.5%)对奶牛瘤胃内纤毛虫数量、pH值、NH3—N及菌体蛋白浓度动态变化、干物质采食量及养分表观消化率的影响。3种籽实分别为葵花籽、胡麻籽、菜籽。结果表明,日粮中添加不同的油料籽实对奶牛瘤胃液纤毛虫数量动态变化影响差异不显著(p>0.05)。     

高精料条件下酵母培养物对山羊瘤胃发酵特性的影响

在高精料日粮条件下,以4头装有永久性瘤胃瘘管的本地山羊为试验动物,采用4×4拉丁方设计,研究酵母培养物对山羊瘤胃液动态发酵特性的影响。结果表明:日粮中添加酵母培养物可显著提高瘤胃液pH值,降低瘤胃液氨氮和乳酸浓度。6h时,30和40g/d试验组pH值分别较对照组提高0.29(P<0.05)和0.30(P<0.05);2h时,20、30和40g/d试验组氨氮浓度分别较对照组降低6.11%(P<0.05)、10.48%(P<0.05)和12.63%(P<0.05)。酵母培养物提高了瘤胃总挥发性脂肪酸(TVFA)浓度,4h时,20g/d试验组TVFA浓度较对照组提高21%(P<0.05);18h时,30g/d试验组TVFA浓度较对照组提高28%(P<0.05)。     

利用体外产气法研究异位酸对山羊瘤胃发酵的影响

应用体外产气法模拟瘤胃发酵,通过测定24 h体外累计产气量、中性洗涤纤维(NDF)的降解率和细菌氮含量,研究添加不同水平异位酸对山羊瘤胃发酵的影响.试验采用单因子设计,异位酸的添加水平分别为0%、0.1%、0.2%、0.4%和0.6%,每个水平4个重复.结果表明,与对照组相比,添加0.2%和0.4%水平的异位酸组能显著提高24 h累计产气量(P＜0.05);NDF降解率显著提高(P＜0.05),其中以0.2%水平的异位酸组NDF降解率最高(P＜0.01);细菌氮含量差异极显著提高(P＜0.01),其中以0.4%水平的异位酸组细菌氮含量最高(P＜0.01).日粮中的异位酸的适宜添加水平为0.2%～0.4%.     

日粮中添加豆油对肉牛瘤胃发酵及营养物质消化率影响的研究

本试验选用４ 头装有永久瘤胃和真胃瘘管的阉牛,采用４ ×４ 拉丁方设计,对照组牛饲喂基础日粮,３ 个试组在基础日粮中分别添加豆油１５０ｇ 、３００ｇ 及４５０ｇ 。探讨日粮中添加豆油对肉牛瘤胃发酵及营养物质消化率的影响。结果表明,日粮中添加豆油使瘤胃总挥发性脂肪酸（ Ｔ Ｖ Ｆ Ａ） 浓度显著下降,３ 个试验组平均总挥发性脂肪酸（ Ｖ Ｆ Ａ） 浓度比对照组下降２２ ．３７ ％ 。日粮日添加４５０ｇ 豆油使瘤胃内及全消化道干物质和有机物的消化率显著下降（ Ｐ＜ ０ ．０５） 。日粮中补充豆油时,随着添加量的增加瘤胃内及全消化道中性洗涤纤维（ Ｎ Ｄ Ｆ） 消化率呈下降趋势,而对瘤胃后 Ｎ Ｄ Ｆ 消化率无影响。日粮中补充豆油对酸性洗涤纤维（ Ａ Ｄ Ｆ） 消化率的影响与对 Ｎ Ｄ Ｆ 消化率的影响相一致。４ 个组脂肪酸表观消化率分别为６０ ．３７ ％ 、７８ ．６７ ％ 、８５ ．３５ ％ 和８７ ．８３ ％ ,随着豆油添加量的增加脂肪酸表观消化率线性提高。     

Effects of feeding salt-tolerant forage cultivated in saline-alkaline land on rumen fermentation, feed digestibility and nitrogen balance in lamb

BACKGROUND: Mixing salt‐tolerant plants with other plants may affect rumen fermentation, which could result in an increase of feed conversion rate. The objective of this study was to evaluate the effects of partially or entirely replacing the corn stover with a mixture of salt‐tolerant forage (Dahurian wildrye grass, weeping alkaligrass and erect milkvetch) in the diet of lambs on ruminal fermentation, feed digestibility and nitrogen (N) balance. Ratios of corn stover to the mixture of salt‐tolerant forages in the four experimental diets were 100:0, 67:33, 33:67 and 0:100, respectively, for control, low (LF), medium (MF) and high (HF). RESULTS: Ruminal pH was lower (P = 0.048) with LF and MF than with control and HF diets. Total VFA concentration was consistently higher (P = 0.039) for LF and MF than for control and HF with increasing amount of salt‐tolerant forage. Ratio of acetate to propionate was linearly (P = 0.019) decreased due to the decrease in acetate production. Digestibilities of OM, NDF and CP in the whole tract linearly (P < 0.002) decreased with increasing amount of salt‐tolerant forage. Similarly, retained N and ratio of retained N to digestible N also linearly (P < 0.005) decreased. CONCLUSION: Feeding salt‐tolerant forage cultivated in saline‐alkaline land improved rumen fermentation with increased total VFA production, and changed the rumen fermentation pattern to increased butyrate production. However, the decreased feed digestibility in the whole digestive tract of lamb may reduce nutrient availability to animals and thus adversely affect animal productivity. Additionally, feeding salt‐tolerant forages may require more protein supplement to meet animal requirements, because of the low protein content and low protein digestibility of the salt‐tolerant forages. Copyright © 2011 Society of Chemical Industry     

Effects of fish meals on rumen bacterial fermentation in continuous culture

Effects of various forms of fish meal on microbial metabolism were investigated in continuous cultures of rumen contents. Five diets were formulated to contain 12% ruminally degradable protein and 47 to 48% nonstructural carbohydrate. Soybean meal was the major protein source in the control diet, whereas in the other four diets, various fish meals were substituted for 6% of total diet DM. Fish meals were: fish meal containing 34.4% FFA, fish meal containing 34.4% FFA with CaCl2 added, fish meal containing 65.6% FFA, and fish meal defatted using 1:1 ethanol:ether extraction. The five treatments were fermented with pH either held constant at 6.2 or not controlled. When pH was maintained at 6.2, the inclusion of any fish meal except defatted fish meal reduced the acetate:propionate ratio, decreased protein digestion, and reduced microbial N produced/per kilogram DM digested when compared with the soybean control. When not controlled, pH decreased after feeding to 6.0 or lower. Under these conditions, the soybean control had a lower acetate:propionate ratio and lower NDF digestion than all diets containing fish meal. In this study, oil-containing fish meal affected microbial metabolism more negatively when the fermentation pH was held at 6.2 than when the pH was 6.0 or lower.     

Effects of varying degrees of synchrony of energy and nitrogen release in the rumen on the synthesis of microbial protein in cattle consuming grass silage

The effect of the degree of synchrony in the ruminal release of energy and nitrogen on microbial protein synthesis (MPS) was examined in cattle consuming grass silage (7.9 kg DM day⁻¹) and a supplement of 1 kg day⁻¹ of sucrose given as an intraruminal infusion. The sucrose was infused in three different patterns to induce varying degrees of synchrony of energy and nitrogen release. Four non‐lactating cows received four experimental treatments in a 4 × 4 Latin square design with periods lasting 14 days. The treatments were (1) the basal diet of silage alone given in two equal meals each day at 10.00 and 22.00 h (BASAL), supplemented with (2) 1.0 kg sucrose given as a continuous infusion (CONT), (3) 1.0 kg sucrose given as two 6‐h infusions starting at 10.00 and 22.00 h (SYNC) and (4) 1.0 kg sucrose given as two 6‐h infusions starting at 16.00 and 04.00 h (ASYNC). The different patterns of infusing the sucrose altered (P < 0.05) the pattern of variation in ruminal concentrations of ammonia and the molar proportions of acetic and butyric acids at times during the interval between meals but none of the sucrose treatments resulted in any increase in the ruminal concentration of lactic acid. All sucrose treatments increased (P < 0.05) MPS relative to BASAL by, on average, about 23 g day⁻¹. The increase in MPS for the SYNC and ASYNC treatments were identical at 20 g kg⁻¹ sucrose. It is concluded that synchronising the rates of ruminal release of energy and nitrogen had no effect on MPS. © 1999 Society of Chemical Industry     

Effects of supplemental butyrate and weaning on rumen fermentation in Holstein calves

The objectives of this study were to determine the effects of the weaning transition and supplemental rumen-protected butyrate on subacute ruminal acidosis, feed intake, and growth parameters. Holstein bull calves (n = 36; age = 10.7 ± 4.1 d; ± standard deviation) were assigned to 1 of 4 treatment groups: 2 preweaning groups, animals fed milk replacer only (PRE-M) and those fed milk replacer, calf starter, and hay (PRE-S); and 2 postweaning groups, animals fed milk replacer, calf starter, and hay without supplemental rumen-protected butyrate (POST-S) or with supplemental rumen-protected butyrate at a rate of 1% wt/wt during the 2-wk weaning transition (POST-B). Milk replacer was provided at 1,200 g/d; starter, water, and hay were provided ad libitum. Weaning took place over 14 d by reducing milk replacer provision to 900 g/d in wk 7, 600 g/d in wk 8, and 0 g/d in wk 9. Rumen pH was measured continuously for 7 d during wk 6 for PRE-S and PRE-M and during wk 9 for POST-S and POST-B. After rumen pH was measured for 7 d, calves were euthanized, and rumen fluid was sampled and analyzed for volatile fatty acid (VFA) profile. Individual feed intake was recorded daily, whereas, weekly, body weights were recorded, and blood samples were collected. Compared with PRE-M, PRE-S calves tended to have a greater total VFA concentration (35.60 ± 11.4 vs. 11.90 ± 11.8 mM) but mean rumen pH was unaffected (6.25 ± 0.22 vs. 6.17 ± 0.21, respectively). Between PRE-S (wk 6) and POST-S (wk 9), calf starter intake increased (250 ± 219 vs. 2,239 ± 219 g/d), total VFA concentrations increased (35.6 ± 11.4 vs. 154.4 ± 11.8 mM), but mean rumen pH was unaffected (6.25 ± 0.22 vs. 6.40 ± 0.22, respectively). Compared with POST-S, POST-B calves had greater starter intake in wk 7, 8, and 9, but POST-B tended to have lower total VFA concentration (131.0 ± 11.8 vs. 154.4 ± 11.8 mM) and lower mean ruminal pH (5.83 ± 0.21 vs. 6.40 ± 0.22). In conclusion, the weaning transition does not appear to affect rumen pH and VFA profile, but supplementing rumen-protected butyrate during the weaning transition increased starter intake and average daily gain. Further, these data suggest that the ability of the rumen to manage rumen pH changes fundamentally postweaning. Why weaned calves with lower rumen pH can achieve higher calf starter intakes is unclear; these data suggest the effect of rumen pH on feed intake differs between calves and cows.     

Effect of humic acid on fermentation and ciliate protozoan population in rumen fluid of sheep in vitro

BACKGROUND: Humic acid (HA) as a product of decomposition of animal and plant tissue is used in animal production as a feed supplement, antimicrobial product and growth stimulator. The objective of the present in vitro study was to investigate the effects of dietary humic acid as a commercial Humacid 60 Basic (H60B) feed additive preparation on rumen fermentation and the ciliate protozoan population in the rumen fluid of sheep using a high fibre (HF) and high concentrate (HC) diet in batch cultures and artificial rumen (RUSITEC). RESULTS: Production of total volatile fatty acids (VFAs) was significantly decreased (P < 0.001) for batch cultures by the HF‐H60B diet. The HF‐H60B diet decreased ammonia N in RUSITEC (P < 0.001). An increase in the population of Enoploplastron triloricatum, Isotricha spp. and Ophryoscolex c. tricoronatus with the HF‐H60B diet and Diploplastron affine with the HC‐H60B was observed. The H60B did not affect the total ciliate population and Entodinium spp. CONCLUSION: It can be concluded that dietary humic acid preparations are not effective as dietary antiprotozoal agents. Humic acid might enhance microbial growth and energy efficiency in doses up to 10 g kg^?1 DM of diet. Copyright © 2009 Society of Chemical Industry     

Effects of variation of dietary sulfur on movement of sulfur in sheep rumen

Effects of variations in dietary sulfur on rumen sulfur dynamics were studied under steady state conditions. In the first experimental period, three sheep were given 33.3 g of a pelleted diet hourly containing 1.59 g sulfur/kg (low) and in the second period the sulfur content was increased to 3.21 g/kg (high) by the addition of sodium sulfate. The daily sulfur intake was 1.158 g on the low sulfur diet and .545 g of this passed from the rumen in protein, .614 g was calculated to be absorbed from the rumen as sulfide, and .052 g was estimated to be recycled to the rumen. For sheep with daily intakes of 2.317 g sulfur, 1.212 g passed from the rumen in protein, 1.078 g was absorbed from the rumen, and .093 g was estimated to be recycled. It was estimated that 127 and 165 g microbial protein were synthesized/kg organic matter "truly digested" in the rumen for low and high sulfur diets, respectively. A simple model using simultaneous equations was proposed to describe rumen sulfur metabolism.     

A comparison of rumen fermentation patterns in sheep and goats given a variety of diets

The rumen fermentation pattern was studied in mature, dry non-pregnant Chios ewes and Damascus goats. They were fed one of five roughages: barley, lucerne or sudex hay, barley straw and acacia leaves and twigs alone and in combination with concentrates (1:1 ratio). Goats had significantly lower pH values when barley hay+ concentrate or sudex hay were fed. The level of ruminal NH₃-N did not differ between species, but it was affected by source and level of dietary protein. The tungstic acid precipitable protein concentration (g litre^?1) in rumen liquor was generally higher in goats than in ewes (6.1 versus 4.9). The molar proportions of individual VFA and total VFA concentration were significantly affected by diet but not by species.     

Effects of variation in soluble carbohydrate intake on sulfur dynamics in the sheep rumen

Two groups of experiments were conducted (named the 15% starch and 30% starch intake experiments) to examine the effects of dietary energy levels on the synthesis of ruminal microbial protein and the absorption of sulfur from the rumen. The level of energy intake affected the absorption rate of sulfide from the rumen, the net microbial protein flow rate, the amount of microbial protein synthesized per kg organic matter ‘truly digested’ in the rumen and the daily flow of recycled sulfur. For the 15% starch and 30% starch intake experiments the absorption of sulfur from the rumen was 1.207 and 1.278 g day^?1 absorbed from 2.298 and 2.212 g intake, respectively, the flow of microbial protein was 80.2 and 92.1 g day^?1, respectively, and the estimated recycled sulfur was 0middot;357 and 0.670 g day^?1, respectively. It was estimated that 18.1 and 20.1 g of microbial protein was synthesized per 100 g of organic matter ‘truly digested’ in the rumen for 15% starch and 30% starch diets, respectively.     

Manipulation of fermentation in the rumen

Artificial saliva (4 litres/day) was infused into the rumen of sheep fed a semi-purified diet at hourly intervals. Dilution rate and the efficiency of synthesis of microbial protein in vivo were increased. The pattern of rumen fermentation was altered; the molar proportion of propionic acid decreased (32–20%) and acetic acid increased (58–66%) with infusion, and there was an increased flow of total amino acids into the duodenum.     

Effects of time at suboptimal pH on rumen fermentation in a dual-flow continuous culture system

Ruminal pH varies considerably during the day, achieving values below 6.0 when cows consume large amounts of concentrates. Low ruminal pH has negative effects on ruminal fermentation. However, previous studies have indicated that rumen bacteria may resist short periods of low ruminal pH, and it is not clear how long this period may be before rumen microbial fermentation is negatively affected. Seven dual-flow continuous culture fermenters (1,320 mL) were used in 3 replicated periods with the same diet (97 g of dry matter/d of a 60:40 forage-to-concentrate diet, 18.3% crude protein, 35.9% neutral detergent fiber), temperature (39°C), and solid (5%/h) and liquid (10%/h) dilution rates to study the effects of increasing time at suboptimal pH on rumen microbial fermentation and nutrient flow. Treatments were a constant pH of 6.4 and 6 different intervals of time during the day (4, 8, 12, 16, 20, 24 h) at suboptimal pH (5.5), with the rest of the day being at pH 6.4. Polynomial equations were derived using the Mixed procedure of SAS, and linear, quadratic and cubic terms were left in the equation if P < 0.10. True organic matter digestion decreased with increasing time at suboptimal pH and was best described by a cubic regression (TOMD = 58.5 − 2.15x + 0.16x² −0.0037x³; R² = 0.74). Digestion of NDF (DNDF = 55.1 − 1.00x; R² = 0.75) and digestion of ADF (DADF = 56.2 − 1.33x; R² = 0.78) decreased linearly with increasing time at suboptimal pH. Total VFA had a cubic response (VFA = 112.7 − 2.09x + 0.17x² − 0.0054x³; R² = 0.82). The proportion of acetate decreased linearly (acetate = 58.7 − 0.61x; R² = 0.79). The propionate proportion increased (propionate = 17.6 + 2.09 × −0.044x²; R² = 0.85) and branched-chain VFA decreased (BCVFA = 4.45 −0.51x + 0.014x²; R² = 0.75) quadratically. The ammonia N concentration (NH₃-N = 5.85 − 0.13x; R² = 0.46) and flow (NH₃-N flow = 0.18 − 0.0039x; R² = 0.43) decreased linearly as the time at suboptimal pH increased. Crude protein degradation (CPd = 41.9 − 1.60x + 0.060x²; R² = 0.71), efficiency of microbial protein synthesis (EMPS = 26.6 − 0.33x + 0.021x²; R² = 0.77), microbial N flow (MN flow = 1.38 − 0.036x + 0.0015x²; R² = 0.77), and dietary N flow (DN flow = 1.49 + 0.041x − 0.0015x²; R² = 0.65) had a quadratic response. The flow of essential, nonessential, and most individual AA increased linearly with increasing time at suboptimal pH. The effects of pH on rumen fermentation appear to start as soon as pH drops to suboptimal pH.