瘤胃灌注大豆小肽对鲁西黄牛营养物质消化代谢的影响

试验选用4头安装永久性三位点瘘管的鲁西黄牛阉牛,采用4×4拉丁方试验设计,瘤胃分别灌注1 000 mL0.9%的生理盐水,100、200、300 g/d的大豆小肽,探讨其对肉牛营养物质消化代谢以及氮平衡的影响。结果表明:灌注大豆小肽对日粮脂肪(EE)、粗蛋白(CP)与酸性洗涤纤维(ADF)的表观消化率无影响(P>0.05);300 g/d组显著提高日粮干物质(DM)、有机物(OM)、中性洗涤纤维(NDF)的表观消化率(P<0.05);灌注小肽显著增加了尿氮的排出量(P<0.05),提高氮的表观消化率与氮沉积(P<0.05);200 g/d与300 g/d组显著降低了十二指肠氮流量占进食量的百分比(P<0.05);300 g/d组显著提高了血浆尿素氮和血浆葡萄糖含量(P<0.05)。试验结果表明,灌注大豆小肽能提高日粮营养成分的消化率,增加氮沉积,综合考虑各因素,在本试验中灌注量以200 g/d最佳。     

十二指肠灌注大豆小肽和氨基酸对奶山羊小肠肽吸收的影响

本试验探讨了十二指肠灌注大豆小肽和氨基酸对奶山羊小肠肽结合氨基酸和游离氨基酸吸收的影响.选取4只体况良好,体重(38.38±3.09)kg的泌乳奶山羊,安装永久性十二指肠近端瘘管和门静脉、肠系膜静脉以及颈动脉慢性血管插管进行试验.采用交叉试验设计,分别向十二指肠灌注60 g/d大豆小肽以及与60g大豆小肽总氨基酸含量相同的氨基酸.结果表明,与灌注氨基酸相比,灌注大豆小肽显著增加肠系膜排流组织(MDV)总肽结合氨基酸净流量(P<0.05),门静脉排流组织(PDV)总肽结合氨基酸净流量高于灌注氨基酸组,但2组间差异不显著(P>0.05).而灌注氨基酸显著增加奶山羊MDV和PDV总游离氨基酸净流量(P<0.05).研究表明,小肠中肽含量的增加可以促使其在小肠的吸收.     

大豆小肽对肉牛瘤胃发酵和养分消化的影响

文章旨在评估日粮添加不同水平的大豆小肽对肉牛瘤胃发酵、微生物菌群数量及养分消化率的影响。试验选择平均体重为(398±12)kg的肉牛12头,随机分为4组,每组3个重复,每个重复1头牛。肉牛饲喂以玉米-黑麦草为基础的日粮,各组肉牛日粮分别补充0、120、240和360 g/d大豆小肽。经过3周试验后,对瘤胃发酵和养分消化进行评估。结果 :大豆小肽添加水平对瘤胃pH、普雷沃氏菌、瘤胃球菌和纤毛虫数量无显著影响(P 0.05)。240 g/d大豆小肽组瘤胃丁酸弧菌数量较对照组显著提高22.67%(P 0.05),而对照组瘤胃链球菌数量较大豆小肽组分别显著提高20.90%、21.65%和19.67%(P 0.05)。随着日粮大豆小肽添加水平的升高,十二指肠和粪中干物质流量表现为显著线性和二次曲线降低(P 0.05),同时干物质总消化率表现为显著线性升高(P 0.05)。360 g/d大豆小肽组十二指肠有机物流量最低(P 0.05),而对照组粪有机物流量最高,总消化率最低(P 0.05)。随着日粮大豆小肽水平的升高,氮摄入量、尿氮排泄量及氮沉积量表现为显著线性升高(P 0.05)。精氨酸消化率随着大豆小肽水平的升高表现为显著线性和二次曲线升高(P 0.05),而赖氨酸消化率表现为显著的二次曲线升高(P 0.05)。结论 :日粮中补充大豆小肽对肉牛瘤胃发酵性能、十二指肠和回肠干物质、有机物、纤维和氨基酸消化有显著改善作用。     

十二指肠灌注DL-蛋氨酸对肉牛营养物质消化率和血液指标影响的研究

根据基础日粮+待测氨基酸法,由十二指肠瘘管连续灌注DL-Met,通过日增重、氮平衡试验、小肠营养物质消化率指标和血浆游离氨基酸含量确定基础日粮条件下十二指肠氨酸最佳灌注量。试验结果表明:III组日增重最高,比I组提高15.27%(P<0.05)II组和III组沉积氮、沉积氮/可消化氮显著高于I组(P<0.05),其中III组高于II组;III组尿中尿素氮显著低于I组(P<0.05)。III组小肠氮的表观消化率最高,比I组高5.72%(P<0.05)。III组血浆氨氮显著低于I组(P<0.05)。血浆Cys和MetIV组显著高于其它3组(P<0.05),而Ser和Ile则相反。III组血浆Leu、Lys、BCAA和EAA显著低于其它各组(P<0.05)。肉牛十二指肠蛋氨酸最佳灌注量为13g/d。     

十二指肠灌注不同水平大豆小肽对奶山羊小肠小肽吸收的影响

本试验旨在研究十二指肠灌注大豆小肽对奶山羊小肠小肽和游离氨基酸吸收的影响。选择7只体况良好、体质量相近的奶山羊((37.88±3.03)kg),安装永久性十二指肠近端瘘管和门静脉、肠系膜静脉近端和远端以及颈动脉慢性血插管进行4×4拉丁方试验,分别从十二指肠灌注生理盐水、60、120、180g.d-1大豆小肽。结果表明,随着十二指肠大豆小肽灌注水平的提高,奶山羊肠系膜排流组织(MDV)总肽结合氨基酸净流量显著增加(P0.05或P0.01);60、120、180g.d-1组门静脉排流组织(PDV)总肽结合氨基酸净流量均显著高于对照组(P0.05),但3个大豆小肽灌注组间无显著性差异(P0.05)。奶山羊小肠对小肽的吸收率随小肠中肽量的增加而下降。随着大豆小肽灌注水平的增加,奶山羊MDV和PDV组织游离氨基酸净流量显著增加(P0.05)。随十二指肠大豆小肽灌注水平的提高,试验羊颈静脉血浆尿素氮浓度显著增加(P0.05),对血浆葡萄糖、胰岛素、生长激素、胰高血糖素和IGF-1浓度没有显著影响(P0.05)。研究结果表明,大豆小肽灌注增加奶山羊小肠中肽结合氨基酸的流量,提高了MDV肽结合氨基酸的净流量,但因肽结合氨基酸吸收率降低或/和肽结合氨基酸吸收细胞降解率提高,降低了进入肠系膜静脉的肽结合氨基酸的比率。     

十二指肠大豆小肽梯度灌注对泌乳奶山羊血液指标、乳成分及肽转运载体在小肠中表达丰度的影响

本试验通过十二指肠大豆小肽梯度灌注,旨在研究不同水平的小肽对泌乳中期奶山羊乳成分、血液生化指标、激素水平及小肠肽转运载体(PepT1)表达活性的影响.试验选用12只平均体重为(38±2)kg、带有十二指肠瘘管的泌乳奶山羊,分成4组,分别灌注小肽0、60、120、180 g/d,试验日粮相同,连续灌注14 d.结果表明:通过小肽的灌注,(1)增加了乳蛋白产量(P＜0.05),乳蛋白含量也有所增加,但仅在120 g/d试验组差异显著(P＜0.05).乳脂产量与乳脂含量随着灌注量的升高呈显著下降趋势(P＜0.05).乳中尿素氮含量随着灌注量的升高而增加(P＜0.05);(2)血清中总蛋白和球蛋白含量均高于对照组,但仅在120 g/d试验组差异显著(P＜0.05).白蛋白含量反而较对照组相比有所降低(P＜0.05),尿素氮的含量显著升高(P＜0.05).血清中生长激素浓度随着大豆小肽灌注量的增加而升高(P＜0.05),胰岛素浓度也表现出增加趋势,但只有在180 g/d试验组差异显著(P＜0.05);(3)PepT1表达在十二指肠、空肠、回肠随着灌注量的增加而升高.小肽灌注组PepT1在十二指肠表达丰度分别是对照组的1.6、2.6、5.4倍;回肠表达丰度是对照组的1.1、1.4、3.3倍;在空肠中表达是对照组的1.1、1.8、2.4倍.随着灌注量的增加,PepT1在十二指肠表达的增加尤为显著,在180 g/d试验组,PepT1十二指肠表达量分别为空肠、回肠的1.5、1.6倍.本研究揭示,小肽的灌注可以提高PepT1表达活性,增加小肽吸收,促进乳蛋白合成,并在120 g/d试验组表现尤为显著.     

十二指肠大豆小肽梯度灌注对山羊乳腺氨基酸吸收与氨肽酶N基因表达的影响

旨在研究乳腺对不同水平大豆小肽的吸收利用情况.试验选用8只带有十二指肠瘘管和颈动脉、乳静脉血插管的泌乳奶山羊(体质量38 kg±k2 kg),采用交叉设计,分别向十二指肠灌注大豆小肽0、60、120和180 g·d~(-1),连续灌注14 d.结果表明:通过小肽的灌注,(1)提高了乳蛋白产量与乳蛋白含量,而且乳蛋白产量显著提高(P＜0.05).乳脂产量与乳脂含量随着灌注量的升高呈显著下降趋势(P＜0.05).(2)乳腺血浆流星有轻微的提高,但不显著(P＞0.05).与对照组相比,各处理组血浆流量/产奶量出现下降,但只有120 g·~(-1)灌注组下降显著(P＜0.05).(3)与对照组相比,大部分游离氨基酸在60和120 g·d~(-1)灌注组吸收量增加,而在180 g·d~(-1)灌注组出现下降趋势.除了PB-Ile,大豆小肽的灌注增加了所有肽结合必需氨基酸的乳腺吸收.但PB-Val、PB-Leu、PB-Phe、PB-Thr、PB-Met和PB-Lys均在120 g·d~(-1)灌注组吸收率最高.非必需氨基酸中,小肽的灌注提高了PB-Ser、PBTyr、PB-Pro的吸收(P＜0.05),而PB-Gly的吸收却出现了下降(P＞0.05).(4)除了Lys,处理组中所有必需氨基酸的乳中分泌量都高于对照组,从0～120 g·d~(-1)试验组,这些氨基酸乳中分泌量随着小肽灌注量的升高而呈增加趋势(P＜0.05);在180 g·d~(-1)灌注组,大部分必需氨基酸的分泌量增加不显著(P＞0.05),且低于120 g·d~(-1)灌注组.(5)小肽的灌注明显促进了APN基因的表达.灌注60、120和180 g·d~(-1)小肽后,氨肽酶N(APN)的表达分别是对照组的13.55、18.69和10.01倍.结论:乳腺组织能够吸收动脉血液中的小肽,大豆小肽的灌注提高了乳蛋白产量显示乳腺组织可以将吸收的小肽用于乳蛋白的合成.但当乳腺所需的氨基酸达到饱和以后,再增加氨基酸的浓度会出现吸收抑制.APN表达变化与乳腺小肽吸收增加相一致,这可能因为APN是调控小肽乳腺吸收利用的主要酶类之一.     

日粮补充苹果酸对牛瘤胃发酵和养分消化代谢的影响

选用8头体重462 kg、年龄3岁、装有永久性瘤胃瘘管的西门塔尔牛阉牛,采用4×4重复拉丁方设计,对照组饲喂基础日粮,处理组分别在基础日粮基础上添加苹果酸70,140和210 g/d,研究苹果酸对西门塔尔牛瘤胃发酵、尿嘌呤衍生物含量、日粮养分表观消化率、能量代谢及氮平衡的影响。结果表明,140和210 g/d组瘤胃pH值显著低于对照组,瘤胃乙酸摩尔比、乙酸/丙酸、氨态氮浓度和乳酸含量显著低于对照组和70 g/d组(P<0.05),瘤胃总挥发性脂肪酸浓度、丙酸和丁酸摩尔比显著高于对照组和100 g/d组(P<0.05)。140 g/d组玉米秸秆干物质、有机物质、中性洗涤纤维和酸性洗涤纤维瘤胃有效降解率显著高于对照组(P<0.05);210 g/d组混合精料干物质、有机物质和粗蛋白质瘤胃有效降解率显著低于对照组、70和140 g/d组(P<0.05)。140 g/d组尿囊素和尿嘌呤衍生物含量显著高于70和210 g/d组及对照组(P<0.05);140和210 g/d组有机物质、粗脂肪、无氮浸出物、中性洗涤纤维和酸性洗涤纤维表观消化率显著高于对照组(P<0.05);140 g/d组消化能、代谢能、沉积能及沉积能/消化能显著高于对照组(P<0.05);140 g/d组沉积氮显著高于对照组(P<0.05)。综合各项指标,苹果酸的适宜添加水平为140 g/d。     

不同过瘤胃氨基酸-脂肪复合物添加水平对山羊饲料养分消化率及氮排泄的影响

为研究不同过瘤胃氨基酸-脂肪复合物添加水平对山羊饲料养分消化率的影响,试验选用4只体重为(59.80±3.23)kg、体况良好的成年崂山山羊公羊,采用拉丁方试验设计,对照组饲喂基础日粮,试验组分别在基础日粮的基础上添加60 g/d.只、120 g/d.只和180 g/d.只过瘤胃氨基酸-脂肪复合物。试验共分为4期,每期14 d,其中预饲期7 d,正式期7 d。结果表明,与对照组相比,试验组能够明显提高日粮养分消化率。其中,120 g/d.只组山羊对饲料干物质、有机物、粗脂肪、中性洗涤纤维和酸性洗涤纤维的消化率均显著提高(P<0.05);180 g/d.只组除酸性洗涤纤维外,其他养分消化率均显著提高(P<0.05),并且粗脂肪消化率极显著高于对照组(P<0.01);在氮排泄方面,各试验组排出氮占食入氮含量较对照组均有不同程度下降,60 g/d.只组下降0.93%(P>0.05),120 g/d.只组下降6.24%(P<0.01),180 g/d.只组下降2.27%(P<0.05)。综上所述,日粮中添加不同水平的过瘤胃氨基酸-脂肪复合物有助于提高山羊日粮中养分消化率,促进氮的沉积,降低了氮的排出量,经回归分析结果表明添加量为117～150 g/d时对提高山羊日粮养分消化率的效果最佳。     

十二指肠灌注蛋氨酸对肉牛小肠氨基酸消化率的研究

根据基础日粮+待测氨基酸法,由十二指肠瘘管连续灌注DL Met,通过小肠氨基酸消化率确定基础日粮条件下十二指肠蛋氨酸最佳灌注量。试验采用4×4拉丁方设计,试牛饲喂相同的基础日粮,DL 蛋氨酸的浓度为0(Ⅰ组)、9(Ⅱ组)、13(Ⅲ组)和17(Ⅳ组)g/d,预试期12d,正试期7d,采用Cr2O3标记物法测定食糜流通量。结果表明:十二指肠灌注13g蛋氨酸(Ⅲ组)显著增加十二指肠Met、Cys、Pro、Lys以及TAA和EAA流通量(P<0 05),降低回肠Asp、Thr、Glu、Gly、Val、Ile、Phe、Lys和His的流通量,但差异不显著(P>0 05),显著提高Asp、Thr、Ser、Glu、Phe、His、Arg在小肠的表观消化率(P<0 05),证明本试验条件下十二指肠蛋氨酸最佳灌注量为13g/d。     

复合异位酸对山羊小肠氨基酸流通量和表观消化率的影响

试验研究了日粮添加复合异位酸对山羊小肠氨基酸流通量和表观消化率的影响。采用3×3拉丁方试验设计,选用3头安装有永久性瘤胃瘘管、十二指肠近端瘘管和回肠远端瘘管、平均体重为(25.4±0.75)kg的健康麻城黑山羊为试验动物。I组为空白对照,饲喂基础日粮。II组、III组分别饲喂含0.3%和0.6%复合异位酸(钠盐形式)的试验日粮。采用Co-EDTA标记法测定小肠氨基酸流通量和表观消化率。结果显示:III组缬氨酸和异亮氨酸十二指肠流通量极显著高于对照组(P0.01),亮氨酸和必需氨基酸显著高于对照组(P0.05);缬氨酸和丙氨酸的小肠表观消化率显著高于对照组(P0.05)。II组缬氨酸和异亮氨酸十二指肠流通量显著高于对照组(P0.05)。III组异亮氨酸十二指肠流通量显著高于II组(P0.05)。     

Effects of small peptides or amino acids infused to a perfused area of the skin of Angora goats on mohair growth

The effect of infusing dipeptides or their amino acids on mohair growth of Angora goats was investigated using a skin perfusion technique. Seven Angora wethers (average BW 24 +/- 2.5 kg) were implanted bilaterally with silicon catheters into the superficial branches of the deep circumflex iliac artery and vein and carotid artery. The experiment consisted of three 28-d phases. In the first 14 d of Phases 1 and 3, saline was infused into deep circumflex iliac arteries supplying skin and in Phase 2 a mixture of dipeptides (methionine-leucine [Met-Leu], lysine-leucine [Lys-Leu]) was infused into the artery on one side, and free amino acids were administered on the other side. Infusion rates of peptides were 0.85 mg/h Met-Leu and 0.85 mg/h Lys-Leu in 2.4 mL saline. Infusion rates of amino acids were 0.474 mg/h Lys, 0.483 mg/h Met, and 0.743 mg/h Leu in 2.4 mL saline. A 100-cm2 area within the perfused region was used to determine mohair growth. Two weeks after the cessation of infusions, perfused areas were shorn. Clean mohair production from the dipeptide- and amino acids-perfused regions were similar (4.21 vs 4.35 g/[100 cm2 +/- 28 d], respectively; P > 0.05). However, clean mohair production during dipeptides and amino acids infusions was greater (P < 0.01) than that observed during saline infusions (3.63 g/[100 cm2 +/- 28 d]). There were no significant differences between dipeptides and free amino acids in concentrations of various hormones and metabolites in blood from deep circumflex iliac veins (P > 0.05). In conclusion, the studied small dipeptides and amino acids similarly increased mohair fiber growth, presumably through supplying limiting amino acids directly to the fiber follicle.     

低蛋白质日粮补充赖氨酸、蛋氨酸对离乳期梅花鹿氮代谢的影响

为研究低蛋白质日粮添加赖氨酸和蛋氨酸对仔鹿氮代谢的影响,采用4×4完全拉丁方试验,选取3月龄、健康、离乳梅花鹿仔鹿4只,体重为(30±0.12)kg(X?±SD),进行消化代谢试验。对照组(Ⅰ组)饲喂16.28%粗蛋白质的高蛋白质日粮,试验组饲喂13.40%粗蛋白质,添加0.23%赖氨酸,并分别添加0(Ⅱ组)、0.06%(Ⅲ组)、0.12%(Ⅳ组)蛋氨酸的低蛋白质日粮。结果表明:1)对照组蛋白质消化率显著高于Ⅱ组(P<0.01)、Ⅲ组和Ⅳ组(P<0.05),脂肪消化率显著低于Ⅱ组(P<0.01),其他营养物质消化率差异不显著(P>0.05)。2)对照组和Ⅳ组蛋氨酸消化率显著高于Ⅱ组和Ⅲ组(P<0.05),对照组其余氨基酸消化率(赖氨酸、胱氨酸除外)显著高于各试验组(P<0.05)。3)对照组吸收氮显著高于Ⅱ组(P<0.01)、Ⅲ组和Ⅳ组(P<0.05),尿氮排放量显著高于各试验组(P<0.05),氮利用率及氮生物学效价低于各试验组(P>0.05)。4)对照组尿嘌呤衍生物总排放量显著大于Ⅱ组(P<0.01)和Ⅲ组(P<0.05),尿囊素显著大于Ⅱ组(P<0.01)、Ⅲ组和Ⅳ组(P<0.05),对照组、Ⅲ组和Ⅳ组黄嘌呤和次黄嘌呤显著高于Ⅱ组(P<0.01)。补充赖氨酸、蛋氨酸可改善低蛋白质日粮仔鹿营养物质消化率利用率,除粗蛋白外其他营养物质消化率与常规蛋白质水平相近,甚至更好,提高氮沉积、氮利用率和生物学效价,改善氮平衡,减少氮排放,降低环境污染。     

The effect of abomasal methionine supplementation on nitrogen retention of growing steers postruminally infused with casein or nonsulfur-containing amino acids

An experiment was conducted to develop a system useful for measuring methionine requirements of growing steers. Seven ruminally cannulated steers (312 kg, gaining .91 kg/d) were fed a diet based on ammoniated corn cobs, corn starch, molasses and urea. Quantities of N and sulfur-containing amino acids disappearing from the small intestine were 96.0 and 14.8 g/d, respectively. Postruminal infusions of Na-caseinate (CAS) resulted in linear (P less than .01) increases in N retention with values increasing from 30.1 g/d with no postruminal CAS infusion to 39.3, 50.8 and 59.2 g/d (averaged across methionine supplementation) when 100, 200 and 300 g/d CAS were infused. Postruminal infusions of a mixture of crystalline L-amino acids (simulating the nonsulfur-containing essential amino acid pattern of casein; SIM) at levels of 100, 200 and 300 g/d also led to linear increases (P less than .01) in N retention with steers retaining 30.9, 38.9 and 50.5 g N/d (averaged across methionine supplementation), respectively. Postruminal infusion of 12 g/d L-methionine across CAS and SIM infusions improved (P less than .01) N retention by 7.6 g/d but infusion of SIM, which is devoid of sulfur amino acids, also increased N retention. Responses to methionine supplementation was greatest when 200 or 300 g/d SIM were abomasally infused. The data are interpreted to demonstrate that, for steers fed a diet containing little true protein, postruminal supplementation with nonsulfur-containing amino acids tended to increase the ability of growing steers to respond to methionine supplementation.     

非常规蛋白饲料原料对泌乳山羊氮代谢和微生物蛋白合成的影响

文章旨在研究不同蛋白质来源精饲料对泌乳山羊氮代谢及微生物蛋白合成的影响。试验选择平均初始体重为(43.62±2.35)kg的泌乳期山羊72头,随机分为3组,每组4个重复,每个重复6头。各组分别饲喂以豆粕、大豆浓缩蛋白和豆科植物(银合欢)为基础的精料,试验为期8周。结果:大豆浓缩蛋白组尿液和尿素氮排泄量较豆科植物组显著提高21.41%和23.31%(P<0.05),但大豆浓缩蛋白和乳尿素氮排泄量最低(P<0.05)。大豆浓缩蛋白组尿液和尿素氮排泄量占体重的比例也显著高于豆科植物组(P<0.05)。大豆浓缩蛋白组氮摄入量最低(P<0.05)。大豆浓缩蛋白组尿氮含量显著高于豆粕和豆科植物组(P<0.05)。豆科植物组微生物氮、微生物蛋白量及合成效率也显著高于豆粕组(P<0.05)。结论:在本研究条件下,以大豆浓缩蛋白为蛋白源的精饲料饲喂哺乳期山羊,尿液氮排泄量更大,导致负氮平衡,而以豆科植物(银合欢)为蛋白源时,可以提高乳山羊瘤胃微生物蛋白合成能力。     

瘤胃保护性氨基酸对内蒙古白绒山羊氮消化代谢的影响

选用9只安装永久性瘤胃瘘管，十二指肠近端瘘管和回肠末端瘘管的内蒙古白绒山羊半同胞羯羊，随机分为3组，即保护性氨基酸组（A组）、常规氨基酸组（B组）和对照组（C组），每组3只进行动物试验。采用体内法研究在相同蛋白质水平（CP 9．93％）日粮条件下，日粮中添加瘤胃保护性蛋氨酸（RPMet）和瘤胃保护性赖氨酸（RPLys）对内蒙古白绒山羊氮消化代谢的影响。结果表明：在内蒙古白绒山羊基础日粮中添加RPMet和RPLys显著地增加了绒山羊的干物质采食量DMI（P〈0．05），提高了机体氮的沉积（P〉0．05），并有降低尿中尿素氮（UUN）排出量的趋势（P〉0．05）。     

The effects of feeding sericea lespedeza hay on growth rate of goats naturally infected with gastrointestinal nematodes

Goat production is increasing in the United States due to high ethnic demand, but infection with gastrointestinal nematode (GIN) parasites is a major constraint to the industry. Increasing GIN resistance to chemical anthelmintics worldwide has led to the development of alternative control strategies, including use of forages containing condensed tannins (CT). An experiment was designed using infected and dewormed male kids (Kiko x Spanish, 6 mo old, 18.9 +/- 3.25 kg) fed diets containing 25% concentrate and either 75% sericea lespedeza [SL; Lespedeza cuneata (Dum-Cours.) G. Don], a high CT forage (87 to 181 g of CT/kg), or 75% bermudagrass [BG; Cynodon dactylon (L.) Pers.] hay (n = 10/treatment). The kids were weighed every 14 d, and fecal and blood samples were taken weekly for fecal egg counts and packed cell volume determination, respectively. Fecal cultures were processed every 14 d to determine CT effect on larval development. At slaughter, adult GIN were collected from the abomasum and small intestines for counting and speciation. Blood samples were also analyzed for plasma urea-N, and ruminal VFA and pH were determined. The infected SL-fed kids had consistently lower (P < 0.05) fecal egg counts than the infected BG goats throughout the trial and greater (P < 0.05) packed cell volume beginning by d 77. Average daily gain was greater (P < 0.001) in kids fed SL- than BG-based diets, regardless of infection status (104.3 +/- 5.0 and 75.5 +/- 4.8 g/d, respectively). Total VFA and acetate concentrations were greater (P < 0.001) in the BG- than in SL-fed goats, whereas propionate levels were unaffected by diet. Acetate:propionate ratio (P = 0.01) and plasma urea-N (P = 0.03) levels were greater in BG-fed goats, whereas rumen pH was greater (P < 0.001) in the SL-fed goats. Feeding SL hay can reduce GIN infection levels and increase performance of goats compared with BG hay.     

青贮饲用油菜对育肥期山羊瘤胃发酵参数及微生物多样性的影响

本试验旨在研究青贮饲用油菜对山羊瘤胃发酵参数及微生物多样性的影响。将24只3月龄左右宜昌白山羊[平均体重(14.83±0.32) kg,公母各半]随机分为2组。试验组饲喂含有青贮饲用油菜的全混合饲粮,对照组饲喂含有青贮全株玉米的全混合饲粮,预试期7 d,正饲期90 d。试验结束时,每组屠宰6只羊,取瘤胃液测定pH、氨态氮、瘤胃液菌体蛋白质、挥发性脂肪酸等指标,并采用16S高通量测序方法分析瘤胃中菌群结构。结果表明,试验组与对照组山羊的平均日增重、干物质采食量和料重比无显著差异(P>0.05)。试验组与对照组间山羊瘤胃液pH值、氨态氮无显著差异(P>0.05);试验组山羊瘤胃液菌体蛋白含量和异丁酸含量显著高于对照组(P<0.05),其他挥发性脂肪酸含量差异不显著(P>0.05);瘤胃菌群结构分析结果表明,试验组和对照组相对丰度大于0.1%的菌门,分别有15和14个,两组中共有的菌门按照丰度排序依次是拟杆菌门、厚壁菌门、变形菌门、螺旋体门和Saccharibacteria,但各菌门丰度组间差异不显著(P>0.05)。属水平上,两个组山羊瘤胃液中普雷沃氏菌属的微生物含量均最多。试验组与对照组有显著差异的菌群Prevotella_1丰度从21.10%减少到16.66%,模糊分类群丰度从1.95%增加到3.19%(P<0.05)。综上所述,饲喂青贮饲用油菜能保持山羊瘤胃内环境及微生物菌群结构稳定,维持瘤胃正常发酵。     

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.     

Effects of supplemental fat source on nutrient digestion and ruminal fermentation in steers

Five Holstein steers (235 kg of BW) fitted with ruminal, duodenal, and ileal cannulas were used in a 5 x 5 Latin square design experiment to determine the effects of supplemental fat source on site and extent of nutrient digestion and ruminal fermentation. Treatments were diets based on steam-flaked corn containing no supplemental fat (control) or 4% (DM basis) supplemental fat as tallow, dried full-fat corn germ (corn germ), corn oil, or flax oil. Fat supplementation decreased (P < 0.08) ruminal starch digestion but increased (P < 0.03) small intestinal starch digestion as a percentage of intake. Feeding corn germ decreased (P < 0.09) ruminal starch digestion and increased (P < 0.03) large intestinal starch digestion compared with steers fed corn oil. Large intestinal starch digestion was less (P < 0.04), and ruminal NDF digestion was greater (P < 0.09) for steers fed tallow compared with steers fed other fat sources. Small intestinal (P < 0.08) and total tract NDF digestibilities were greater (P < 0.02) for steers fed corn germ than for those fed corn oil. Feeding tallow increased total ruminal VFA (P < 0.03) and NH(3) (P < 0.07) concentrations compared with steers fed the other fat sources. Feeding corn germ led to a greater (P < 0.02) rate of ruminal liquid outflow compared with corn oil. A diet x hour interaction (P < 0.04) occurred for ruminal pH, with steers fed corn oil having the greatest ruminal pH 18 h after feeding, without differences at other time points. Fat supplementation increased (P < 0.09) ruminal concentrations of Fusobacterium necrophorum. Duodenal flow of C18:3n-3 was greater (P < 0.01) for steers fed flax oil compared with those fed corn oil. Feeding corn germ led to less (P < 0.01) ruminal biohydrogenation of fatty acids compared with corn oil. Steers fed tallow had greater small intestinal digestibility of C14:0 (P < 0.02) and C16:1 (P < 0.04) than steers fed the other fat sources. Fat supplementation decreased (P < 0.06) small intestinal digestibility of C18:0. Feeding corn germ decreased (P < 0.10) small intestinal digestibility of C18:1 compared with corn oil. It appears that source of supplemental fat can affect the site and extent of fatty acid and nutrient digestion in steers fed diets based on steam-flaked corn.