不同糊化度的糊化淀粉尿素在瘤胃中氨的释放规律的研究

３头带瘤胃瘘管的肉牛饲喂６种不同糊化加工程度的糊化淀粉尿素（Ｓ１、Ｓ２、Ｓ３、Ｓ４、Ｓ５、Ｓ６），其淀粉的糊化度分别为（％）０、５２．７１、６３．８３、６８．１５、７１．１４、７５．８７。在饲喂后１小时和２小时瘤胃液氨浓度（ｍｇＮＨ３／１００ｍｌ）达到高峰，其氨浓度峰值分别为１６２．２、１５２．４、８５．２、８１．７、７７．７、７０．７，与糊化淀粉尿素的糊化度呈显著性相关（ｒ＝－０．８５，ｎ＝６，ｐ＜０．０５）。同时Ｓ１、Ｓ２的ＮＨ３浓度峰值与Ｓ３、Ｓ４、Ｓ５、Ｓ６的值差异极显著（ｐ＜０．０１），Ｓ１、Ｓ２之间及Ｓ３、Ｓ４、Ｓ５、Ｓ６之间差异不显著（ｐ＞０．０５）。     

糊化淀粉尿素用于育肥牛日粮的饲养试验

本试验探讨糊化淀粉尿素应用于育肥牛日粮对其日增重、饲料报酬及经济效益的影响。选择年龄、体重及体况相近的杂交肉牛30头，体重325．9±26．0kg，随机分为3组，每组10头，I组为糊化尿素组，Ⅱ组为添加尿素组，Ⅲ组为对照组（即棉籽饼组）。试验日粮组成为麦秸、鲜酒糟及混合精料。试验期为2个月。试验结果表明，Ⅰ、Ⅱ、Ⅲ组试验牛平均日增重分别为1．393kg、1．03kg和1．14kg，精料／增重分别为3．05:1、3．74：1、4．13:1。试验期间Ⅰ、Ⅱ、Ⅲ组牛的经济效益以糊化尿素组最高，为304元／头；其次棉籽饼组为164元／头；最差为添加尿素组为146．3元／头。     

在生长獭兔日粮中添加尿素的试验研究

选用生长獭兔２７只，随机分为３组，分别饲喂加入０％、１．０％和２．０％尿素的日粮，研究对试兔增重、饲料转化率、屠宰率及肉和毛皮品质的影响。试验结果表明：１０％、２０％尿素组的试兔增重分别比对照组提高２．８３～９．２１％，随尿素添加量的增加，每天每只兔的采食量稍增加，蛋白效率比以１．０％尿素组最好。日粮中添加１．０％、２．０％的尿素对生长獭兔的屠宰率、肉及毛皮质量均无不良影响，１．０％尿素组的单位增重成本比对照组降低１．１９％。因此，生长獭兔日粮中添加１．０％尿素是可行的     

低蛋白质氨基酸平衡饲粮对早期断奶仔猪腹泻和生产性能的影响

本研究选用１８头２８±１日龄断奶的杂交仔猪（平均体重约５．５ｋｇ），研究低蛋白质氨基酸平衡饲粮对早期断奶仔猪腹泻和生产性能的影响。试验结果显示：（１）低蛋白质氨基酸平衡饲粮使仔猪血浆挥发性盐基氨含量、血浆尿素氨含量和腹泻指数降低（Ｐ＜０．０５或０．０１）。（２）采食全植物蛋白型氨基酸平衡饲粮（ＣＰ１８．３％）的仔猪，其平均日增重（ＡＤＧ）、平均日采食量（ＡＤＦＩ）和料肉比（Ｐ／Ｇ）与采食复合蛋白型对照饲粮（ＣＰ１９．７％）的仔猪差异不显著（Ｐ＞０．０５），但前者的增重成本比后者降低（Ｐ＜０．０５）３１％。（３）采食复合蛋白型氨基酸平衡饲粮（ＣＰ１８．４％）的仔猪的生产性能优于采食复合蛋白型对照饲粮（ＣＰ１９．７％）的仔猪，前者的ＡＤＧ和ＡＤＦＩ分别提高（Ｐ＜０．０５）６１％和３２％，Ｆ／Ｇ和增重成本分别下降（Ｐ＜０．０５）２４％和３７％。（４）采食全植物蛋白型氨基酸平衡饲粮的仔猪，其ＡＤＧ和ＡＤＦＩ低于（Ｐ＜０．０１）采食复合蛋白型氨基酸平衡饲粮的仔猪。前者的Ｆ／Ｇ和增重成本趋于高于后者，但差异不显著（Ｐ＞０．０５）。以上结果表明，低蛋白质氨基酸平衡饲粮可显著降低仔猪断奶后腹泻和提高仔猪生产性能。复合蛋白型?     

低蛋白质饲粮中添加尿素对肉兔生长发育及血液指标的影响

本试验旨在研究低蛋白质饲粮中添加尿素对肉兔生长发育与血液指标的影响。采用单因子随机区组试验设计,选择 １２０只 ５０日龄、体重相近的健康新西兰兔,随机分为 ４组,１个对照组和 ３个试验组,每组 １５个重复,每个重复 ２只。对照组饲喂粗蛋白质含量为 １１．１１％的基础饲粮,３个试验组分别饲喂在基础饲粮中以糊化淀粉缓释尿素的方式添加 １％、２％和 ３％尿素的试验饲粮。预试期为 １０ｄ,正试期为 ３０ｄ。结果表明：试验第 ２天,３％尿素组 ８０％试验兔因发生氨中毒而死亡。１％尿素组试验兔末重、增重和日增重均极显著高于对照组和 ２％尿素组（Ｐ＜０．０１）。与对照组相比,１％和 ２％尿素组试验兔全血氨氮含量、血清谷丙转氨酶活性显著或极显著升高（Ｐ＜０．０５或 Ｐ＜０．０１）,而肝脏重和系数则显著或极显著降低（Ｐ＜０．０５或 Ｐ＜０．０１）。２％尿素组试验兔日干物质进食量、胴体重和屠宰率均极显著低于对照组和 １％尿素组（Ｐ＜０．０１）,而料重比则极显著高于对照组和 １％尿素组（Ｐ＜０．０１）。２％尿素组试验兔血清尿素氮含量以及谷草转氨酶、碱性磷酸酶活性均极显著高于对照组和 １％尿素组（Ｐ＜０．０１）。２％尿素组试验兔心脏、脾脏和肾脏重均显著低于对照组和 １％尿素组（Ｐ＜０．０５）,而肾脏系数则极显著高于对照组和 １％尿素组（Ｐ＜０．０１）。２％尿素组试验兔胃重、十二指肠重与长、空肠重与长、回肠重与长、盲肠重与系数、蚓突重与系数及长、大肠重与长显著或极显著低于对照组和 １％尿素组（Ｐ＜０．０５或 Ｐ＜０．０１）,且回肠系数及盲肠长显著或极显著低于对照组（Ｐ＜０．０５或 Ｐ＜０．０１）。由此得出,低蛋白质饲粮中添加 ３％的尿素会造成肉兔氨中毒死亡;添加 ２％的尿素会使肉兔生长发育停滞;添加 １％的尿素可改善肉兔育肥性能,但会对肝脏的发育产生不利影响。     

奶牛氨基浓缩料的研究和应用

对糊化淀粉尿素中尿素的分解速度和氨基浓缩料代替饼类饲喂泌乳牛效果的研究表明，糊化淀粉尿素的分解速度显著减慢（Ｐ＜０．０１），其高峰期ＮＨ＿３－Ｎ浓度只有尿素的５９％。用糊化淀粉尿素配制的氨基浓缩料，含粗蛋白质７２％。用８％的氨基浓缩料代替１５％的饼类饲喂泌乳牛，使产奶量提高１６．４％（Ｐ＜０．０５），乳脂率和牛奶比重无显著变化（Ｐ＞０．０５），浓缩料日粮能使泌乳曲线高峰期维持较长时间。在奶牛日粮中用８％的氨基浓缩料替代１５％的饼类，降低了成本，提高了产奶量。     

不同处理尿素对育肥肉牛增重效果的影响

选用18头18月龄架子牛，随机分为3组，其中对照组饲喂含有豆粕的饲料，试验Ⅰ组饲喂加工的糊化淀粉尿素，试验Ⅱ组饲喂未经任何处理的尿素，试验期为90 d。结果表明，3组平均日增重分别为1427.7、1793.3、1638.8 g/头。     

颗粒化TMR对肉牛增重效果的研究

本试验在冬季舍内拴系饲养条件下进行。选择健康、初始体重１４５ｋｇ±４０ｋｇ西杂公牛４０头，随机分成两组，一组为试验组，另一组为对照组。两组试验牛饲喂相同日粮，试验组饲喂ＴＭＲ（全混合日粮）颗粒料，对照组饲喂ＴＭＲ粉状料，试验期为６５ｄ。每日观察牛的反刍行为，记录每天采食量，试验结束时空腹称重。试验结果如下：试验组和对照组采食后３ｈ反刍的次数占３０次观察值的频率分别为３１％和３３％，二者无显著差异（Ｐ＞０．０５）；全期日增重，试验组和对照组分别为０９６９ｋｇ±０１９ｋｇ和０８４６ｋｇ±０．２４ｋｇ；日采食量分别为５８８ｋｇ±０．０９ｋｇ和５８４ｋｇ±０．０６ｋｇ（风干基础），饲料转化效率分别为６１７±００３和６９０±０１２。全期日增重和饲料转化效率，两组间差异显著（Ｐ＜０．０５）。试验组每增重１ｋｇ的饲料成本较对照组降低０２２元，全期增重较对照组多９ｋｇ，仅此全期试验组每头牛比对照组多增收６６１０元。试验结果表明，利用颗粒化ＴＭＲ日粮持续育肥肉牛在经济上是可行的。     

发酵蛋白粉对仔猪的饲用价值

本试验旨在研究发酵蛋白粉代替鱼粉和豆粕对仔猪的饲用价值，选择日龄、体重相近健康仔猪（杜×长×大）４０头，按单因子完全随机设计法分成两组，每组２０头，各设置两个重复。用含２％鱼粉的饲料饲喂对照组，用含７％发酵蛋白粉替代进口鱼粉和豆粕的饲料饲喂试验组。结果表明，对照组、试验组的平均日增重分别为３８５ｇ±４７ｇ、３７８ｇ±２５ｇ，饲料转化率分别为２２６∶１、２３７５∶１，毛利润分别为８０７６元、７８７４元。经ｔ检验，对照组和试验组的饲料转化率的差异显著（Ｐ＜０．０５），平均日增重和经济效益的差异均不显著（Ｐ＞０．０５）。     

早期断奶仔猪日粮中添加不同种类酸化剂的效果

选用杂种仔猪（杜洛克×长白×大白）１２５头，于２８±３日龄断奶，以玉米－豆粕－鱼粉型日粮饲喂，进行为期２８天的饲养试验，研究日粮中添加柠檬酸（１％）、磷酸（０．３％）及复合酸（０．３％和０．５％）对仔猪生产性能、日粮蛋白质消化率、胃肠道消化酶活力及肠道大肠杆菌数的影响。结果表明，日粮中添加各种酸化剂可提高仔猪日增重９－１７％（Ｐ＞０．０５）；日粮中添加柠檬酸和复合酸则可显著提高饲料转化效率１１－１５％（Ｐ＜０．０５）；日粮中添加０．３％磷酸可提高饲料利用效率８％（Ｐ＞０．０５）。添加酸化剂对日粮蛋白质消化率无影响。柠檬酸和磷酸有降低胃肠道ｐＨ值、提高胰蛋白酶、淀粉酶活力及减少结肠中大肠杆菌数的趋势。     

糊化淀粉尿素对山羊饲喂效果的研究

糊化淀粉尿素对山羊饲喂效果的研究@顾炳龙@王福泉...     

一种新型缓释尿素替代日粮中部分豆粕对肉牛生长性能、养分消化率及血液生化指标的影响

试验旨在研究一种新型缓释尿素替代日粮中部分豆粕对肉牛生长性能、养分消化率及血液生化指标的影响。选择18头健康、体重相近(315±5)kg、7月龄左右生长期西门塔尔杂交公牛,随机分为豆粕组、缓释尿素组和普通尿素组3组,每组6头牛。豆粕组饲喂含11.12%豆粕(粗蛋白质(CP)为15.51%、干物质(DM)为48.06%)的试验日粮(精粗比4∶6)。按照等能等氮原则,缓释尿素组和普通尿素组饲喂含缓释尿素和普通尿素分别占各自日粮的1.41%和1.15%,即2个试验组分别用缓释尿素和普通尿素替代豆粕组日粮中75%豆粕。预试期14 d,正试期60 d。结果表明:①各组间平均日增重和料重比均无显著差异(P>0.05),但缓释尿素组和普通尿素组的平均日采食量(ADMI)显著低于豆粕组(P<0.05)。②缓释尿素组和普通尿素组的干物质和有机物(OM)表观消化率显著高于豆粕组(P<0.05);缓释尿素组粗蛋白质的表观消化率显著低于普通尿素组(P<0.05),但与豆粕组相比无显著差异(P>0.05);普通尿素组粗脂肪(EE)表观消化率最低,豆粕组最高,各组间均存在显著差异(P<0.05);各处理组间的中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)的表观消化率均无显著差异(P>0.05)。③与豆粕组相比,缓释尿素替代日粮中部分豆粕未对肉牛各项血液生化指标产生影响(P>0.05);缓释尿素组的白蛋白(ALB)、谷丙转氨酶(ALT)和谷草转氨酶(AST)均显著高于普通尿素组(P<0.05)。由上述结果可知,缓释尿素和普通尿素可替代日粮中部分豆粕应用于肉牛生产中,且缓释尿素替代豆粕效果优于普通尿素。     

Renal excretion of urea in reindeer. Effect of nutrition.

Renal reabsorption of urea was studied in 8 9-month old reindeer calves fed low protein (19–34 g crude protein, mostly lichens) and high protein (68–69 g crude protein, lichens + soybean meal) diets.Low protein diets fed for a 3-month period resulted in an average renal reabsorption of 93% of the filtered urea, while only 50 % was reabsorbed on the high protein ration. It was calculated that if the reabsorbed urea was used completely for protein synthesis in the rumen, 4 g crude protein could be made daily in the lichen fed animals. This amount would be a very significant contribution to the nitrogen economy of animals which are usually in a negative nitrogen balance when lichens are the main food consumed.     

Urea utilization of growing lambs. 2. Growth experiments

In two growth experiments with 30 lambs per group the influence of urea (1-2% of the ration) and straw (20-30% of the ration) on the performance was studied under conditions of intensive fattening. The content of native crude protein in the rations varied between 10.1 and 18.4% of the DM. In experiment 1 the lambs of the two groups which received mixed feed for fattening lambs without urea on average consumed with 1.02 and 1.11 kg DM resp., 696 and 757 EFUcattle resp. and 173 and 189 g crude protein resp. per animal and day. The groups with wheat or barley and urea consumed 1.06 and 0.96 kg DM resp., 714 and 627 EFUcattle resp. and 209 and 155 g crude protein resp. Their weight gain of 247 g/animal and day was 24% and that of 230 g resp. 26% higher than that in the control groups without urea. The lowest dry matter intake (0.91 and 0.82 kg resp.) was shown by the animals of the groups which received wheat or barley without urea. In the second experiment the control group achieved an average daily weight gain of 327 g at an expenditure of 2.24 kEFUcattle/kg weight gain. Despite a partly higher dry matter intake, the daily EFUcattle intake was between 12.2 and 24.5% lower in the straw groups and energy expenditure increased between 12.0 and 27.8%. Urea supplements of between 1 and 2% improved dry matter, EFUcattle and crude protein intake and thus weight gain.     

Cecotrophy behavior and use of urea as non-protein nitrogen (NPN) source for capybara (Hydrochoerus hydrochaeris)

Fifteen female adult capybaras, with initial average body weight (BW) of 32.7 (±?5.8) kg, were kept in individual pens to evaluate effect of supplementation of concentrate feed and its supply time on cecotrophy behavior frequency. The animals were allocated in a completely randomized design, with five animals per treatment, receiving three diets: grass only, grass and grain corn offered in a single meal, and grass and grain corn offered in two daily meals; all cecotrophy acts were recorded. Later, in a second experiment, five capybaras received five levels of urea in their diet: 0, 10, 20, 30, and 40 g urea/100 kg BW, replacing soybean meal as true protein source, in a 5?×?5 Latin square design. The animals were weighed and their blood was collected every 2 weeks. The frequency of cecotrophy (Ps?<?0.05) was higher when the capybaras were fed grass only (0.5?±?0.07 acts/h) than when they received grass and corn in a single meal (0.3?±?0.05 acts/h) and grass and corn supplied in separate meals (0.1?±?0.03 acts/h). With increased urea in their diet, the capybaras showed initial signs of chronic intoxication, together with increments in serum urea (r?=?0.87, P?<?0.05) and a decreasing trend in daily weight gain (r?=??0.38, P?=?0.06). Therefore, when including concentrate feeds in capybara diet, these must be mixed with roughage in a single meal to avoid high decrease in the frequency of cecotrophy behavior and increase in dry matter intake. The replacement of soybean meal with urea in capybara diet is not recommended.     

大豆胰蛋白酶抑制因子对獭兔氮平衡和养分消化率的影响

试验选择（63±4）日龄、平均体重为（1150.5±124.0） g的健康美系獭兔20只,随机分为5组,每组4只兔,公母各半。试验日粮分别含有25%生大豆、25%化学钝化大豆、25%热处理大豆、25%豆粕和13%生大豆+12%豆粕。胰蛋白酶抑制因子含量（实测值）分别为6.55、 1.99、1.73、 0.81和3.97 mg/g。试验结果表明,25%生大豆组显著降低饲料氮表观消化率（P<0.05）,显著增加粪氮排出（P<0.05）,对尿氮无显著影响;化学钝化、热处理及生大豆+豆粕组粪氮、氮消化率同豆粕组间无显著差异（P>0.05）。饲料干物质、有机物质、无氮浸出物、粗脂肪、粗纤维表观消化率5组间无显著差异（P>0.05）。     

Influence of dietary crude protein on peanut skin digestibility and utilization by feedlot steers

Peanut skins were fed at 15% of steer diets in metabolism and feedlot trials. Elevation of dietary protein using soybean meal or soybean meal plus urea and ammoniation of skins were evaluated as methods of overcoming detrimental performance and digestibility effects of tannins in peanut skins. Digestibility of dry matter, crude protein and energy were not different (P greater than .05) for steers fed a control diet with 11.4% crude protein with no skins compared with high-protein 15% peanut skin diets with soybean meal (15.5% crude protein) or soybean meal plus urea (16% crude protein). Dry matter, crude protein and energy digestibilities of control and of high-protein peanut skin diets were higher (P less than .05) compared with an 11.4% crude protein peanut skin diet and a 12.2% crude protein diet with ammoniated peanut skins. Ether extract digestibility was higher (P less than .05) for all peanut skin diets compared with the control. Nitrogen retention (g/d) was not different (P greater than .05) for control and high-protein peanut skin diets, and nitrogen retention on these diets was higher (P less than .05) compared with the lower protein and ammoniated peanut skin diets. Diets fed in the metabolism trial, except for the ammoniated peanut skin diet, were fed to 96 steers (345 kg initial wt) in a 109-d feedlot trial. Performance was lower (P less than .05) for steers fed the lower-protein peanut skin diet compared with other treatments through d 56; this diet was discontinued as a treatment on d 62.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of different high levels of soy extract pellets in the ration on the digestibility of crude nutrients, basic and sulfur-containing amino acids of wheat in colostomized laying hybrids

In two digestibility experiments with 4 colostomized laying hybrids each, the influence of 12.5% (ration 1) and 25% soybean meal (ration 2) on the digestibility of the crude nutrients, the basic and sulphur-containing amino acids in the wheat rations was tested. In ration 1 the digestibility of the crude protein was 84.9%, of the crude fat 56.6% and that of the N-free extractives 87.4%; for ration 2 the values were 83.6%, 47.4% and 82.5%. The digestibility values for wheat acquired with the difference method for ration 1 were 85.7% for crude protein, 57.0% for crude fat and 89.8% for N-free extractives; energy concentration was 766 EFUhens. For wheat supplemented with 25% soybean meal the same digestibility value of the crude protein could be ascertained, the digestibility of the crude fat and the N-free extractives, however, was lower than for ration 1 so that an energy concentration lower by 3.9% was calculated. The possible causes of the influence of the different levels of lysine and thioamino acids on the digestibility of these amino acids of wheat are described.     

Effect of ruminal protein degradability on growth and N metabolism in growing beef steers

The objective of two experiments was to correlate plasma levels of urea N (PUN) and the percentage of urine N in the form of urea (UUN) to weight gain in response to different dietary protein regimens for growing Angus steers. In Exp. 1, 60 steers (302 kg BW) were assigned to various levels of dietary N (control plus supplemental N to provide from 100 to 400 g more crude protein daily) within two sources of supplemental N (soybean meal [SBM] or a mixture of two parts corn gluten meal:one part blood meal [CGM:BM]). In Exp. 2, 27 steers (229 kg BW) were fed two levels of SBM, and half of the steers received growth-promoting implants. Steers were housed in groups of 12 and fed individually for 84 d in both experiments. Corn silage was fed at a restricted rate to minimize orts. Jugular blood and urine samples were collected during the experiments. In Exp. 1, maximal ADG of steers fed SBM (1.0 kg) was reached with 671 g/d total crude protein, or 531 g/d metabolizable protein. Maximal ADG of steers fed CGM:BM (0.91 kg) was reached with 589 g/d total crude protein, or 539 g/d metabolizable protein. The DMI was higher (P < 0.07) for steers fed SBM (6.37 kg/d) than for steers fed CGM:BM (6.14 kg/d). Increasing ruminal escape protein from 36% (SBM) to 65% (CGM:BM) of CP decreased (P < 0.05) endogenous production of urea, as evidenced by lower concentrations of urea in blood and lower UUN. In Exp. 2, increasing supplemental protein from 100 to 200 g/d increased (P < 0.05) ADG and PUN. Implants lowered (P < 0.05) UUN, particularly at the higher level of supplemental protein. Protein supplementation of growing steers can be managed to maintain acceptable ADG yet decrease excretion of urea in the urine.     

Protein supplement resistant against ruminal degradation as a factor improving utilization of urea in ruminant feeding

The metabolic and productive effects of the blood meal and formaldehyde (FA) treated casein supplements (5-10% of crude protein content) given with urea concentrates in sheep and fattening bulls were investigated. The blood meal has a similar composition of essential amino acids (EAA) to casein. The mean solubility of the FA treated casein and the blood meal after 6 hours of incubation in the sterilized rumen contents amounted 10.5% and 8.5% respectively. The average rumen ammonia concentration and plasma urea level was the highest in bulls fed urea ration without protected protein supplement. The supplementation of this ration with blood meal diminished the large daily fluctuation of plasma AA level and increased plasma EAA/NEAA ratio. The blood meal supplement improved the nitrogen retention in sheep (14%) and body gains in bulls (9%) but did not influence digestible coefficients and rumen protein synthesis in sheep.