赖氨酸席夫碱对绵羊瘤胃内的原虫数和营养物质消化的影响

选用4只体重在40kg左右,安装永久性十二指肠瘘管的中国美利奴(新疆型)细毛羊,采用拉丁方设计,分别添加3.42g和6.84g赖氨酸席夫碱(分别含赖氨酸2g、4g),同时添加2.56g和5.12g赖氨酸盐酸盐作为对照(分别含赖氨酸2g、4g),研究对绵羊瘤胃消化代谢的影响。结果显示:与添加赖氨酸组相比,赖氨酸席夫碱对绵羊的瘤胃原虫数量没有显著影响,对绵羊瘤胃内干物质、有机物、粗纤维和纤维素的表观消化率也均无显著作用。     

添喂赖氨酸及赖氨酸席夫碱对绵羊瘤胃发酵的影响

选取4只安装永久性瘤胃瘘管的中国美利奴(新疆型)细毛羊,采用4×4拉丁方设计,分别添喂2、4 g/d赖氨酸席夫碱和24、g/d赖氨酸对照(以赖氨酸含量计),以研究其对瘤胃发酵的影响。结果表明:添喂赖氨酸席夫碱4 g/d组瘤胃乙酸和总挥发性脂肪酸浓度分别低于赖氨酸4 g/d组9.44%和7.24%(P<0.05)。赖氨酸席夫碱添喂量从2 g/d增加到4g/d时,丙酸和丁酸平均含量分别增加了8.20%和10.64%(P<0.05)。添喂赖氨酸席夫碱,绵羊干物质采食量、瘤胃pH值和NH3-N浓度分别在1 374.21~1 419.01 g、6.14~6.54和11.31~28.21 mg/100 mL范围之间,各组无显著差异。以上结果说明:添喂赖氨酸席夫碱比添喂赖氨酸降低了瘤胃乙酸和总挥发性脂肪酸浓度,改变了瘤胃发酵类型。     

添喂赖氨酸席夫碱铜配合物对绵羊瘤胃发酵的影响

 选用4只体重约40 kg、安装永久性瘤胃瘘管的新疆美利奴羯羊按分期试验设计，分别添喂赖氨酸席夫碱-铜配合物0（第Ⅰ期）、4（第Ⅱ期）、8（第Ⅲ期）g/d·只，以研究不同水平的赖氨酸席夫碱铜配合物对绵羊瘤胃发酵的影响。结果表明：随着添喂水平的提高，绵羊对玉米秸秆干物质的采食量增加，其中添喂量为8 g/d·只组与0 g/d·只组相比，采食量提高了12.5％（P＜0.05）。瘤胃液pH在4 g/d·只组与对照组之间无明显差异（P＞0.05），添喂8 g/d·只时在前3 h内具有明显减缓瘤胃液pH下降的作用。各组瘤胃液NH3-N含量差异不明显（P＞0.05），但8 g/d·只组的整体瘤胃液NH3-N含量有降低趋势。添喂赖氨酸席夫碱-铜配合物可降低乙酸和TVFA含量，提高丙酸和丁酸含量，使瘤胃发酵由乙酸型向丙酸型转变。本试验结果表明，添喂赖氨酸席夫碱铜配合物对绵羊瘤胃发酵有一定的调节作用。     

添喂赖氨酸席夫碱 铜配合物对绵羊瘤胃发酵的影响

选用4只体重约40 kg、安装永久性瘤胃瘘管的新疆美利奴羯羊按分期试验设计，分别添喂赖氨酸席夫碱-铜配合物0（第Ⅰ期）、4（第Ⅱ期）、8（第Ⅲ期）g/d·只，以研究不同水平的赖氨酸席夫碱 铜配合物对绵羊瘤胃发酵的影响。结果表明：随着添喂水平的提高，绵羊对玉米秸秆干物质的采食量增加，其中添喂量为8 g/d·只组与0 g/d·只组相比，采食量提高了12.5％（P＜0.05）。瘤胃液pH在4 g/d·只组与对照组之间无明显差异（P＞0.05），添喂8 g/d·只时在前3 h内具有明显减缓瘤胃液pH下降的作用。各组瘤胃液NH3-N含量差异不明显（P＞0.05），但8 g/d·只组的整体瘤胃液NH3-N含量有降低趋势。添喂赖氨酸席夫碱-铜配合物可降低乙酸和TVFA含量，提高丙酸和丁酸含量，使瘤胃发酵由乙酸型向丙酸型转变。本试验结果表明，添喂赖氨酸席夫碱 铜配合物对绵羊瘤胃发酵有一定的调节作用。     

瘤胃保护性氨基酸在奶牛日粮中的应用

日粮中大部分蛋白质在瘤胃中被降解,而增加日粮蛋白质的饲喂量,随之会增加瘤胃内蛋白质的降解量。为了减少瘤胃内蛋白质的降解损失,曾采用各种措施提高日粮中瘤胃非降解蛋白质(UDP)的量,但过多的UDP又会影响微生物蛋白质的合成,导致进入小肠的微生物蛋白质的数量减少。蛋氨酸和赖氨酸被认为是合成乳和乳蛋白的主要限制性氨基酸,而添加游离的氨基酸在瘤胃中很快被降解,必需以某种形式加以保护,使其在瘤胃内稳定,在真胃释放,在小肠吸收。本文综述了瘤胃保护性氨基酸(RPAA)的保护形式、包被物、RPAA的作用以及影响RPAA利用效果的因素。     

过瘤胃保护氨基酸提高奶牛乳蛋白转化效率的研究

为提高奶牛乳蛋白含量和饲料蛋白质用于产奶的转化效率,选择体况、胎次、泌乳期相近的中国荷斯坦奶牛27头,采用L9（34）正交试验设计,研究奶牛不同小肠可消化蛋白（IDCP）供应水平日粮添加过瘤胃保护氨基酸（RPAA）对乳蛋白率含量和IDCP转化为乳蛋白效率的影响。结果表明,IDCP按《中国奶牛饲养标准》（2004）推荐需要量92%水平供应,组合添加过瘤胃保护赖氨酸（RPlys）32 g/d＋过瘤胃保护蛋氨酸（RPmet）8 g/d,日粮干物质中NDF水平控制在37%～41%,可有效提高泌乳前期奶牛乳蛋白含量与IDCP用于泌乳的转化效率。     

瘤胃投饲不同水平保护赖氨酸对肉牛小肠氨基酸流量和消化率的影响

采用基础日粮 待测氨基酸法,研究添加不同水平保护赖氨酸对肉牛小肠氨基酸流量和消化率的影响.基础日粮由小麦糠、玉米和豆粕等组成,能量和蛋白质等营养水平按肉牛营养需要和饲养标准供给.选择体况良好、安装永久性瘤胃瘘管、十二指肠前端和回肠末端瘘管的利木赞×鲁西黄牛杂交公牛6头作为试验动物,采用6×6拉丁方设计,试验设6个赖氨酸水平,分别在基础日粮的基础上添加0、6、9、12、15和18 g/d包被赖氨酸,对肉牛十二指肠、回肠氨基酸流通量进行了研究.结果表明瘤胃投饲保护赖氨酸能显著增加十二指肠EAA、TAA、Met、Ile、Leu、Lys、Glu的流通量(P＜0.05);进而提高EAA、TAA、Thr、Cys、Val、Met、Ile、Lys、Ala、Tyr和Pro在小肠的表观消化率(P＜0.05).本试验条件下赖氨酸最适添加量为15 g/d.     

腐植酸钠对绵羊瘤胃消化代谢的影响

选4只安装永久性瘤胃瘘管和十二指肠瘘管的中国美利奴(新疆型)细毛羊,采用4×4拉丁方设计,分别添喂腐植酸钠0、2、4、6g/d,以研究其对绵羊瘤胃消化代谢的影响。结果表明:采食后3h,4g/d组和6g/d组的瘤胃pH值分别比对照组降低了1.26%和1.10%(P<0.05)。采食后3h,2g/d组、4g/d组和6g/d组的瘤胃液氨态氮浓度分别比对照组降低了13.75%、18.09%和16.03%(P<0.01)。添加4g/d组显著提高了干物质、有机物的前胃消失量和消失率(P<0.05),添加6g/d组显著提高了干物质的前胃消失量(P<0.05);微生物蛋白到达小肠量有随腐植酸钠添加量的增加而提高的趋势(P>0.05)。添加腐植酸钠有提高羊瘤胃微生物合成的作用,因而可促进瘤胃消化代谢。     

用血清游离氨基酸测定法评价过瘤胃氨基酸的功效

血清游离氨基酸测定法是测定过瘤胃氨基酸功效的一种有效方法。这种方法即可以反应出样品的抗瘤胃微生物降解能力，又可以反应出样品在小肠中的释放氨基酸能力。其原理是，当饲料中的氨基酸到达小肠后，就会被小肠所吸收，血清中的游离氨基酸浓度就会上升，如果饲料中的氨基酸不能到达小肠，血清中的游离氨基酸浓度就不会上升，血清游离氨基酸水平与到达小肠的氨基酸量有正相关性。通过测定血清游离氨基酸就可以了解到真正能够被动物吸收的氨基酸的数量。 明尼苏达大学兽医学院报道（１９８１），每天在饲料中添加８０ｇ普通蛋氨酸，血清中…     

粗料型日粮条件下口服福尔马林对小尾寒羊成母羊消化代谢的影响

本试验选取6只装置永久性十二指肠和回肠瘘管、体重约55 kg的成年小尾寒羊母羊,按0（对照期）或0.9 mL/kg日粮（试验期）喂给福尔马林（各期n=6）,收集十二指肠和回肠食糜,并进行消化代谢试验,以研究在粗料型日粮条件下口服福尔马林对绵羊消化代谢的影响。结果表明,口服福尔马林使绵羊的自由采食量增加13.0%（P<0.01）;前胃有机物（OM）和纤维素（Cel）的消化量分别增加21.9%（P<0.01）和29.7%（P<0.01）;到达小肠的OM、粗蛋白质（CP）、微生物蛋白、过瘤胃蛋白、总氨基酸（TAA）和赖氨酸（Lys）量分别增加5.2%（P<0.01）、21.5%（P<0.01）、13.2%（P<0.05）、29.4%（P<0.05）、18.0%（P<0.05）和21.8%（P<0.05）;小肠消化吸收的OM、CP、TAA和Lys量分别增加52.1%（P<0.01）、34.7%（P<0.01）、34.5%（P<0.05）和32.8%（P>0.05）;日粮DM、OM、CP和Cel的（表观）消化率分别提高9.2%（P<0.05）、9.2%（P<0.05）、4.6%（P<0.05）和5.8%（P<0.05）;氮、钙和磷保留量分别增加了28.3%（P<0.01）、30.8%（P<0.01）和9.5%（P<0.05）。因此,在粗料型日粮条件下绵羊口服福尔马林可以提高瘤胃消化能力、提高采食量、增加小肠营养物质特别是氨基酸的消化吸收量、显著改善机体的营养状况。     

精料型日粮条件下添喂气溶胶OT对小尾寒羊前胃和小肠消化吸收的影响

试验选取6只1~1.5岁,体重(55.3±3.8)kg,装置永久性十二指肠近端T型瘘管和回肠末端T型瘘管的小尾寒羊公羊,收集十二指肠和回肠食糜,通过自身对照试验,研究在精料型(玉米秸秆占30%)日粮条件下添喂气溶胶OT(0.8 g/kg日粮)对小尾寒羊前胃和小肠消化吸收的影响。结果表明,添喂气溶胶OT使小尾寒羊干物质自由采食量增加23.6%(P<0.01)。前胃干物质、有机物、粗蛋白质和纤维素的消化量分别增加39.2%(P<0.01)、37.3%(P<0.01)、21.8%(P<0.01)和13.4%(P<0.01);到达小肠的干物质、有机物、粗蛋白质、微生物蛋白质和过瘤胃蛋白质分别增加8.9%(P<0.01)、8.8%(P<0.01)、21.3%(P<0.01)、29.3%(P<0.01)和13.1%(P<0.01);总氨基酸、赖氨酸、蛋氨酸、苏氨酸、缬氨酸和苯丙氨酸分别增加45.6%(P<0.01)、62.7%(P<0.01)、40.8%(P<0.01)、32.8%(P<0.01)、32.0%(P<0.01)和32.3%(P<0.01)。小肠干物质、有机物、粗蛋白质、钙和磷消化吸收量分别增加28.7%(P<0.01)、29.8%(P<0.01)、28.7%(P<0.01)、26.6%(P<0.01)和13.1%(P<0.01);小肠总氨基酸、赖氨酸、蛋氨酸、异亮氨酸、精氨酸和组氨酸消化吸收量分别增加37.6%(P<0.01)、56.9%(P<0.01)、28.6%(P<0.01)、40.9%(P<0.01)、41.5%(P<0.01)和51.7%(P<0.01)。由以上得出结论,添喂气溶胶OT可以提高小尾寒羊自由采食量,增加前胃和小肠营养物质消化吸收量,显著改善宿主的营养供应。     

Site and extent of digestion and amino acid flow to the small intestine in beef cattle consuming limited amounts of forage

Eight Angus x Gelbvieh heifers (445 +/- 74.5 kg) fitted with ruminal and duodenal cannulas were used in a 4 x 4 Latin square double double-crossover designed experiment to assess the effect of restricted forage intake on site and extent of digestion and flow of essential AA amino acids to the small intestine. Heifers were fed chopped (2.54 cm) bromegrass hay (9.2% CP, 64% NDF on an OM basis) at one of four percentages of maintenance (30, 60, 90, and 120%). Experimental periods were 21 d in length, with 17 d of adaptation followed by 4 d of intensive sample collection, after which maintenance requirements and subsequent level of intake were adjusted for BW change. True ruminal OM, NDF, and N digestion (g/d) decreased linearly (P < 0.001) with decreasing forage intake. When expressed as a percentage of OM intake, true ruminal OM and N digestibility were not affected (P = 0.23 to 0.87), whereas ruminal NDF digestibility tended to increase (P = 0.09) as forage intake decreased. Total and microbial essential amino acid flow to the duodenum decreased linearly (P = 0.001) from 496.1 to 132.1 g/d and 329.1 to 96.0 g/d, as intake decreased from 120 to 30% of maintenance intake, respectively. Although the profile of individual essential amino acids in duodenal digesta (P = 0.001 to 0.07) and isolated ruminal microbes differed (P = 0.001 to 0.09) across treatment, the greatest difference noted for total and microbial essential amino acid profile was only 0.3 percentage units. Because total and microbial flow of essential amino acids to the small intestine decreased as OM intake decreased, but true ruminal degradability of individual essential amino acids (P = 0.17 to 0.99) and digesta essential amino acid profile were comparable across treatments, total essential amino acid supply to the small intestine was predicted using OM intake as the independent variable. The resulting simple linear regression equation was: total essential amino acid flow = (0.055 x OM intake) + 1.546 (r2 = 0.91). The model developed in this experiment accounted for more of the variation in the data set than the current beef cattle NRC model, which under-predicted total flow of essential amino acids to the duodenum. The prediction equation developed herein can be used to estimate the supply of essential amino acids reaching the small intestine when formulating supplements to compensate for potential amino acid deficiencies resulting from restricted forage intake.     

Nitrogen balance and amino acid disappearance from the small intestine in calves fed soybean meal-, toasted soybean meal- or corn gluten meal-supplemented diets

Nine crossbred (Hereford X Angus X Charolais) heifer calves (139 kg; 6 mo of age) with abomasal and ileal cannulas were used in a repeated design to evaluate N balance and amino acid disappearance in the small intestine. Calves were fed either soybean meal (SBM), toasted SBM (TSBM, 93 C for 90 min) or corn gluten meal (CGM) as supplemental protein sources. Each calf received approximately 83 g N/d from a cottonseed hull-corn based diet with 43% of the total dietary N supplied by the test proteins. Each experimental period consisted of a 10-d adaptation, 6-d digesta collection and 5-d excreta collection. Following the first 21-d period, calves were randomly re-allotted to treatment and the sampling process was repeated. Dry matter (64%) and N digestibilities (61%) and N retention (36.8 g/d) were similar (P greater than .10) among treatments. Nitrogen flow to the small intestine was similar for TSBM- and CGM-fed calves (119.1 g/d), but greater (P less than .01) than for those offered SBM (96.3 g/d). Offering TSBM and CGM resulted in greater quantities of essential, nonessential and total amino acids reaching the abomasum compared with SBM. Total amino acid flow to the small intestine was 100, 120 and 128% of intake for SBM, TSBM and CGM, respectively. Numerically, amino acid digestibility was lower in CGM-fed calves. Methionine digestibility was highest (64.6%), while histidine was lowest (43.7%). Feeding CGM may result in greater quantities of amino acids reaching the small intestine; however, several of these amino acids may be less digestible than for TSBM.     

Crude protein and essential amino acid requirements in chicks during the first week posthatch

1. This study examined optimal lysine and sulphur amino acid supply in the first week posthatch in broilers and the relationship between essential amino acids and dietary crude protein during the first week posthatch on performance at 7 d and through marketing. 2. The optimal supply during the 7 d posthatch using a 230 g/kg crude protein diet for sulphur amino acids was 9.1 and for lysine was 10.3-10.8 g/kg with maximal body weight (BW) or feed efficiency as the criteria. 3. Feeding diets with crude protein content ranging from 200 to 260 g/kg with either constant amounts of essential amino acids at different crude protein levels or constant ratios of essential amino acids to crude protein resulted in enhanced performance at 7 but not at 4 d with high protein intake and proportionally increased essential amino acids. 4. Performance on diets with crude protein ranging from 160 to 280 g/kg, with constant ratios of essential amino acid to crude protein, was much enhanced with the high crude protein diets at 7 d. All chicks were transferred to standard diets after 7 d and the BW advantage due to the balanced amino acid-high crude protein diet remained through marketing. 5. Thus increasing essential amino acids in a constant ratio to crude protein enhanced performance during the 7 d posthatch.     

饲粮能量和蛋白质水平对滩羊小肠中小肽和氨基酸转运载体mRNA表达量的影响

本试验旨在研究饲粮能量和蛋白质水平对滩羊小肠中小肽和氨基酸转运载体mRNA表达量的影响。选取112只健康、体重相近的滩羊,随机分成4组,每组4个重复,每个重复7只羊。标准水平的饲粮能量和蛋白质水平参考《肉羊饲养标准》(NY/T 816—2004),各组试验滩羊分别饲喂不同能量和蛋白质水平饲粮:0.84×标准水平(Ⅰ组)、0.96×标准水平(Ⅱ组)、1.08×标准水平(Ⅲ组)和1.20×标准水平(Ⅳ组)。试验根据羊体重分2个阶段:29~35 kg和36~40 kg。于每个阶段末,每个重复屠宰1只试验羊,取其小肠组织样,运用实时荧光定量PCR技术,研究小肽转运载体1(Pep T1)、y+型氨基酸转运载体1(CAT1)、兴奋性氨基酸转运载体3(EAAT3)mRNA表达量的变化。结果表明:1)在29~35 kg阶段末,小肠中Pep T1 mRNA的表达量随着饲粮能量和蛋白质水平的提高呈先下降再上升的趋势,Ⅱ组显著低于其他3组(P0.05);Ⅳ组小肠中CAT1 mRNA的表达量显著高于其他3组(P0.05);Ⅲ组小肠中EAAT3mRNA的表达量显著高于其他3组(P0.05)。2)在36~40 kg阶段末,Ⅱ组小肠中Pep T1mRNA的表达量显著高于其他3组(P0.05);Ⅱ组小肠中CAT1 mRNA的表达量显著高于Ⅲ组(P0.05);小肠中EAAT3 mRNA的表达量随着饲粮能量和蛋白质水平的提高呈上升趋势,Ⅲ组和Ⅳ组小肠中EAAT3 mRNA的表达量显著高于Ⅰ组和Ⅱ组(P0.05)。由此可见,饲粮能量和蛋白质水平会影响滩羊小肠中Pep T1、CAT1、EAAT3 mRNA的表达量,使机体对小肽和氨基酸的吸收利用率随之改变,以适应滩羊的生长发育。     

仔猪小肠对二肽吸收特点的研究

本试验采用体外外翻肠囊的方法研究了等摩尔浓度的Ｌ 甘氨酸 Ｌ赖氨酸组成的二肽（Ｇｌｙ－Ｌｙｓ）和游离甘氨酸和赖氨酸混合物（Ｇｌｙ＋Ｌｙｓ）在仔猪小肠各段的吸收特点。将仔猪小肠划分为空肠前段、中段、后段和回肠段,分别在各段设置了两个不同的培养液处理组,分别是浓度为２０ｍｍｏｌ／Ｌ的Ｇｌｙ－Ｌｙｓ和Ｇｌｙ＋Ｌｙｓ混合物培养液组。每个处理３个重复（回肠段无重复）,每个重复为一个外翻肠囊,将每个外翻肠囊置１０ｍｌ培养液中培养１５分钟。旨在比较：体外培养１５分钟后,同一浓度下的Ｇｌｙ－Ｌｙｓ和Ｇｌｙ＋Ｌｙｓ在外翻肠囊各部位的吸收差别,从而确定Ｇｌｙ－Ｌｙｓ在仔猪各肠段的吸收特点。结果表明,同等摩尔浓度下,Ｇｌｙ－Ｌｙｓ组中的赖氨酸和甘氨酸在仔猪空肠中段肠组织的累积量显著大于Ｇｌｙ＋Ｌｙｓ组;从肠囊在１５分钟培养后总的氨基酸摄入量上看,Ｇｌｙ－Ｌｙｓ组的赖氨酸和甘氨酸在空肠中段高于Ｇｌｙ＋Ｌｙｓ组,且二者在赖氨酸上的差异显著。这说明,二肽中甘氨酸和赖氨酸至少在空肠中段的运输系统有别于游离态的甘氨酸和赖氨酸,且对二肽的运输显得比对游离氨基酸的运载更有效。     

敖汉细毛羊小肠可吸收氨基酸适宜模式的研究

选用9只体况良好,体重35～45 kg的1.5周岁敖汉细毛羊半同胞羯羊,安装永久性瘤胃瘘管、十二指肠近端瘘管和回肠末端瘘管进行试验,试验采用随机区组试验设计,3个试验组为在基础日粮条件下的3种十二指肠氨基酸灌注模式,分别为M100、M85+H15和M70+H30,旨在寻找出一种相对平衡的有利于羊毛纤维生长的敖汉细毛羊小肠可吸收氨基酸适宜模式.试验结果显示,改善小肠可吸收氨基酸模式,可明显提高敖汉细毛羊的产毛性能.在本试验条件下,敖汉细毛羊小肠可吸收氨基酸适宜模式接近M70+H30.     

Substitution of protein feed through lysine-supplemented high-protein wheat during the rearing and laying period of hens. 3. Effect of graded lysine doses on the crude nutrient content of carcasses and on the level of amino acids and GOT activity in the blood of young hens]

A large-scale trial was carried out under commercial conditions to investigate to which extent the feeding of rations with varying lysine content to young hens would influence the crude nutrient content of the body fractions and might change the pattern of amino acid composition and the activity of GOT in the blood. Four rations were fed each containing 14.2% crude protein, 626-633 EFh units/kg and 0.59%, 0.61%, 0.54% and 0.46% lysine. The crude protein and crude fat content of the total body and of body fractions were in no case found to be related to the feeding regime. The proportion of crude ash in the "remainder of non-utilizable parts", in "bones", "intestinal and abdominal fat", "ovaries" and "small intestine" decreased with the decreasing lysine content of the rations. The concentrations of free lysine, histidine, arginine, and phenylalanine in the deproteinized blood plasma of the young hens were significantly (a = 0.01) lower in the birds of the lysine deficient group than in the hens of the other groups. Positive regressions were calculated for the lysine content or the content of aspartic acid in the ration and the pattern of free amino acids in blood plasma. Positive and negative linear relationships were found to exist between the concentrations of free lysine, and those of histidine, arginine or threonine, and serine. A close correlation existed between the total amount of essential amino acids in blood plasma and the lysine concentrations of the plasma. Increasing lysine supplementation produced a decline in the N content of the whole blood and blood corpuscles but a rise in the N content of blood plasma. The activity of GOT in the blood of young hens was not found to be useful as an indicator of the quality of dietary proteins.     

低蛋白饲粮补充4种氨基酸对肉用羊增重与肉质中氨基酸含量及血清学的影响

本试验旨在研究不同水平低蛋白饲粮补充过瘤胃氨基酸对育肥杜寒杂交肉用母羊增重、血清中蛋白与激素指标、肌肉中氨基酸含量和肉品质的影响,探索育肥肉羊饲粮低蛋白质含量的理论价值和应用效果。选用150只体重相近4月龄育肥杜寒杂交肉用母羊,随机分成5组,每组3个重复,每个重复10只羊。对照组饲喂粗蛋白质水平为16%的饲粮,试验组饲喂氨基酸平衡低蛋白饲粮,分为LP14组(饲粮CP=14%)、LP12组(饲粮CP=12%)、LP10组(饲粮CP=10%)和LP12+NPN组(饲粮CP=12%,添加1%尿素),各试验组饲粮中都添加过瘤胃赖氨酸、蛋氨酸、苏氨酸和精氨酸,使其和对照组饲粮中这4种氨基酸的含量保持一致,试验期90 d。结果表明:(1)不同水平的低蛋白饲粮在补充过瘤胃氨基酸后,对育肥杜寒杂交肉用母羊的试验末重、净增重和饲料转化比均无显著性影响(P>0.05),对照组干物质采食量高于各试验组(P<0.01),LP12+NPN组育肥羊干物质采食量高于其他低蛋白组(P<0.01)。(2)各组间试验羊血清总蛋白(TP)、球蛋白(GLB)、生长激素(GH)、类胰岛素样生长因子I(IGF-I)均无显著性差异(P>0.05),低蛋白组育肥羊血清尿素氮(BUN)显著低于对照组(P<0.01)。(3)各组肉羊背最长肌在肉色、滴水损失、pH0、pH24、熟肉率以及剪切力上均差异不显著(P>0.05)。(4)各组间试验羊的背最长肌中氨基酸的含量差异不显著(P>0.05)。在本试验条件下,降低育肥杜寒杂交肉羊饲粮粗蛋白质水平1~4个百分点并补充过瘤胃赖氨酸、蛋氨酸、苏氨酸、精氨酸和尿素,不会影响其增重情况、血清指标和肉品质,即低蛋白饲粮补充过瘤胃氨基酸可以满足肉羊育肥阶段的营养需要。