Ruminal degradability and intestinal digestibility of individual amino acids in mixed diets with different crude protein levels measured by the modified in vitro three‐step and mobile nylon bag technique

The ruminal degradability and intestinal digestibility of dry matter (DM), crude protein (CP) and amino acids (AA) in three total mixed rations with different CP levels were estimated using the modified in vitro three‐step procedure (TSP) and mobile nylon bag (MNB) technique on growing lambs. The ruminal effective degradability of DM and CP did not respond with increasing dietary CP level. However, the intestinal digestibility of DM was significantly increased with increasing dietary CP level estimated by TSP (P < 0.05) or MNB method (P < 0.01). Intestinal digestibility coefficients of CP determined by TSP were lower than those of the MNB method. Histidine was extensively degraded by rumen micro‐organisms, while tyrosine was the most anti‐degradable AA among the samples. The ruminal AA degradability exhibited no significant differences except for threonine, tryptophan, alanine, aspartic acid and proline for the three diets. Similarly, only a few AAs (i.e. histidine, methionine, tryptophan, aspartic acid and cysteine in TSP; histidine, tryptophan, aspartic acid and serine in MNB) had significant differences in their intestinal digestibility; in addition, values of MNB were lower than that of the TSP method, indicating that intestinal digestibility of DM seems to be overestimated in TSP, while that of CP might be overestimated in the MNB method.     

体外产气法与尼龙袋法评定粗饲料干物质降解率的相关性分析

为寻求可在实验室条件下简单地评定饲料降解性能的方法,试验以玉米秸秆及不同尿素、石灰比例复合处理的玉米秸秆为发酵底物,对饲料体外产气量和尼龙袋瘤胃干物质降解率作了相关性分析。统计分析表明,体外产气量与体内干物质降解率呈高度正相关,相关系数分别为:对照组0.967、料A0.964、料B0.999和料C0.994。结果证明,在对饲料降解性能及潜在可降解能力作快速、定性判断时,体外产气法可以代替尼龙袋法。     

Effects of drought‐stressed temperate forage legumes on the degradation and the rumen microbial community in vitro

According to climate change scenarios, central Europe may expect extending drought periods during summer. Lower water availability may influence the ruminal digestion of individual forage legume species differently. To test this hypothesis, Lotus corniculatus L. (var. Bull), Medicago lupulina L. (var. Ekola), Medicago falcata L. (wild seeds) and Trifolium repens L. (var. Rivendel) were each grown in parallel lots of control and drought‐stressed monocultures. Rainout shelters (installed in May 2011 on a regrowth after first cut until harvest in mid of June) withheld rainfall of 40 mm in the drought stress treatment. Samples of dried (60°C) and milled (5 mm screen) forage legumes were incubated in a simulation experiment using Rusitec to assess drought effects on parameters for microbial metabolism. Degradability of dry matter and organic matter as well as methane production decreased in incubations with drought‐stressed compared to control variants of legume species. Degradability of crude protein, neutral detergent fibre, acid detergent fibre and residual organic matter including non‐fibre carbohydrates and lipids were affected by interactions between drought stress and species. Significant interactions were also found for ammonia concentrations, molar SCFA proportions and the microbial communities. It is concluded that drought stress for growing forage legumes influences their ruminal degradation and fermentation as well as the ruminal microbial communities of Bacteria and Archaea differently in a legume species‐dependent manner.     

不同粗饲料分级指数混合粗饲料与不同比例精饲料混合日粮体外有机物消化率研究

本试验通过体外连续培养分析了高、低分级指数混合粗饲料日粮24h连续培养中不同时间点培养液中的有机物消化率的动态变化。试验结果表明,高分级指数混合粗饲料日粮不需提高精饲料的比例就有较高的有机物体外消化率(IVOMD),且提高精饲料水平未必能提高其IVOMD,而低分级指数混合粗饲料日粮只有提高精饲料水平才能达到高分级指数混合粗饲料日粮的效果。     

Effect of oat decortication on chemical composition,in vitro digestibility and in situ degradability

The effect of decortication on chemical composition and degradability characteristics of four Danish oat varieties was investigated. Effective degradability (ED) and post-ruminal disappearance (PRD) were measured by in situ and mobile bag techniques respectively. Decorticated oat showed higher (p = .01) concentrations of crude protein (CP; 134 vs. 108 g/kg DM) and crude fat (71.6 vs. 53.1 g/kg DM) and a higher (p = .001) organic matter digestibility (OMD; 888 vs. 703 g/kg OM) than oat. The content of total fatty acids (FA) in DM was higher in decorticated oat. The proportion of linoleic acid (C18:2 n6) increased (p < .05) due to decortication, while the linolenic acid (C18:3 n3) proportion of total FA decreased in decorticated oat. Decortication increased (p = .01) the concentration of amino acids (AA), but the proportion of lysine in total AA decreased (p < .002). Effective degradability (ED) of both DM and CP was (p < .001) higher in decorticated oat. Decortication increased the total tract disappearance (TTD) and PRD of CP (p < .001). In conclusion, decortication can be used as a practical approach to increase the nutritional value of oat.     

不同牧草品种对体外发酵产气特性的影响

采用改进的体外产气技术评价了10种不同牧草的体外产气特性.利用非线性回归方程获得了Gompertz模型的发酵动力学参数(理论最大产气量、产气速率常数和延滞时间),分析了不同品种牧草间发酵动力学参数的差异及发酵动力学参数与营养成分之间的相关关系.结果表明,不同品种牧草间产气动力学参数差异显著(P<0.05).理论最大产气量、产气速率常数和产气延滞时间分别以苏丹草、黑麦草和桂牧1号最高,而以鲁梅克斯、鲁梅克斯和苏丹草最低.相关分析表明理论最大产气量和累积产气量分别与OM含量、NDS/CP值及(NDS-Ash)/CP值呈极显著正相关关系(P<0.001),而与CP含量呈极显著负相关关系(P<0.01).产气速率常数与营养成分无显著相关性.产气延滞时间与半纤维素的含量呈极显著正相关关系(P<0.01),而与NDS/CP值和(NDS-Ash)/CP值呈极显著负相关关系(P<0.001).结论认为牧草中非结构性碳水化合物与蛋白质比例决定了体外发酵产气的特性.     

Effects of dietary supplementation of spices on forage degradability,ruminal fermentation,in vivo digestibility,growth performance and nitrogen balance in Black Bengal goat

The objective of the study was to evaluate the effects of spices on forage utilization and nitrogen (N) emission using in vitro and in vivo approach. A 6 × 5 factorial triplicate arrangement was used to assess the in vitro degradability of rice straw with control (without spices) and individual (40 mg/g rice straw) spices (cumin, coriander, clove, black cumin, turmeric) at five different incubation times. In vitro dry matter (DM) and organic matter (OM) degradability of rice straw were highest in presence of spices except for clove. Clove significantly reduced the total volatile fatty acids concentration, molar proportion of acetate and propionate ratio, but increased propionate production. Acetate and butyrate production were not affected by treatments. The ammonia‐nitrogen concentration was lowest for clove and turmeric compared to other spices. Rumen pH was unchanged but gradually decreased over the incubation period. For in vivo study, 12 bucks with average live weight 7.65 ± 0.19 kg were assigned to a completely randomized design with three treatments and four replicates for a 28‐day period. Bucks were fed a total mixed ration without (0 g/kg DM) or with (2.5, 7.5 g/kg DM) clove supplementation. DM intake, body weight and apparent total tract digestibility of crude protein (CP) and acid detergent fibre (ADF) were not affected by increasing dietary doses of clove but tended (p = .09) to increase DM and OM digestibility. The urinary N and urine urea N concentration of bucks decreased linearly with incremental doses of clove diet. In contrary, clove supplementation had positive effects on plasma urea N and retained N in bucks. We concluded that though some spices had positive effects on ruminal digestion and fermentation, the dosage level assessed in the current study (up to 7.5 g/kg DM clove) can be promoted as an effective dietary approach to mitigate N losses in bucks.     

耐盐牧草对南疆地区盐渍土的适应和改良研究

以4种耐盐碱牧草(紫花苜蓿、苏丹草、美国饲用甜高粱和墨西哥玉米)为研究对象,采用生物防治盐碱化方法来分析其对南疆地区盐碱化土壤改良的可行性,以期为改良利用盐渍土壤提供理论基础。结果表明,墨西哥玉米对南疆盐渍土的改良最为显著(P<0.05),其农艺性状和产草量也最佳;其次是紫花苜蓿,其抗逆性强、生产性能较好、营养丰富、经济价值高以及兼有固氮和提高土壤肥力等优点,使其成为改良南疆盐渍土合适的选择。在南疆盐渍区形成以墨西哥玉米和紫花苜蓿为主,美国饲用甜高粱和苏丹草为辅的种植模式,可有效地降低土壤盐分。     

不同品种牧草间组合时体外产气发酵特性研究

采用体外发酵产气技术研究了鲁梅克斯杂交酸模-三叶草分别与皇竹草、桂牧1号、冬牧70、矮象草、牛鞭草、黑麦草和苏丹草按0∶100、25∶75、50∶50、75∶25和100∶0的比例进行组合时的体外发酵产气特性。结果表明,当鲁梅克斯-三叶草分别与皇竹、桂牧1号和冬牧70组合时,产气量和理论最大产气量以鲁梅克斯-三叶草占75%时最高,而与黑麦草组合时则以25%时最高,并显著(P<0.05)高于其占75%的组合。与矮象草和苏丹草组合时以其占50%时最高,而与牛鞭草组合时则以50%最低。当鲁梅克斯-三叶草与除黑麦草之外的牧草组合时,产气速率随鲁梅克斯-三叶草所占比例的上升而上升,与黑麦草组合时,产气速率则呈相反方向变化,但不同组合比例间无显著差异。当鲁梅克斯-三叶草与除皇竹、桂牧1号、牛鞭草和冬牧70以外的禾本科牧草组合时,不同比例的牧草组合不同发酵时间点之间的正组合效应达到了显著水平。结论认为,3种牧草间组合可不同程度地提高牧草的体外发酵产气量。     

瘤胃尼龙袋法和体外产气法评定反刍动物饲料的营养价值的比较

试验通过评定菜籽粕、玉米、米糠、苜蓿、玉米青贮和玉米秸秆的营养价值来比较瘤胃尼龙袋法和体外产气实验。结果表明:各种饲料的干物质有效降解率分别为52.90%、54.27%、65.70%、40.76%、37.24%和38.17%,精饲料干物质有效降解率(EDMD)中,a部分占比例较高(其中米糠达到64.51%);每克饲料DM的渐进产气量(A)分别为105.00、180.51、109.30、172.71、147.76和148.66 mL,粗饲料的产气量普遍高于精饲料;两种方法中,产气参数A、B与EDMD均呈负相关(r=-0.55和r=-0.61)。从速率曲线来看,降解速率曲线主要反映了b部分的降解情况,而饲料产气的速率曲线却能明显反映出两相的发酵情况。     

干燥方法对几种牧草营养价值和体外消化率的影响

研究了不同干燥方法对盛世紫花苜蓿、环峡南苜蓿、特高多花黑麦草营养价值和体外消化率的影响,结果表明:喷化学干燥剂和压扁茎秆结合喷化学干燥剂使两种豆科牧草茎叶干燥速度趋于一致,缩短了干燥时间,减少了营养物质损失,从而提高了干草的质量;喷化学干燥剂在缩短特高多花黑麦草干燥时间上无效,但在提高其体外消化率上效果显著;与自然晒干和阴干相比,压扁茎秆,喷化学干燥剂及两者结合使用有效提高了牧草的体外消化率。     

密闭气袋在牛卵母细胞体外成熟培养中的应用

通过简易避光密闭气袋在人体呼出的气相环境下（CO2浓度约5%,O2浓度约15%）,利用生化培养箱进行牛卵母细胞的体外成熟培养。结果显示,牛卵母细胞在密闭气袋中培养与对照组（正常培养）相比成熟率（74.79%比71.69%,P〉0.05）、孤雌激活后卵裂率（83.07%比81.39%,P〉0.05）和囊胚发育率上（26.75%比22.87%,P〉0.05）均无显著差异,但是密闭气袋培养各项数据均略高于对照组。本试验验证了该技术的方便性和有效性,为此技术在生产实践中的推广应用提供依据。     

酒糟和醋糟营养成分差异及其瘤胃降解特性分析

本试验旨在评价酒糟、醋糟等非常规饲料资源的饲用价值,为酒糟醋糟资源应用于肉牛养殖提供数据参考.试验选用山西不同地区酒糟、醋糟试样5个,试样编号分别为白酒糟、啤酒糟、醋糟1、醋糟2、醋糟3,发酵原料分别为白酒糟(高粱)、啤酒糟(大麦+大米)、醋糟1(高粱+大麦)、醋糟2(大麦+玉米)、醋糟3(高粱+玉米).通过实验室常规...     

饲粮中添加沙棘果渣对体外瘤胃发酵参数和营养物质有效降解率的影响

本试验旨在研究饲粮中添加沙棘果渣(SBP)对体外瘤胃发酵参数和营养物质有效降解率的影响。试验选用6只健康、1.5岁左右、体重30～45 kg、安装瘤胃瘘管的杜×寒杂交F1肉羊羯羊。试验采用体外产气法和尼龙袋法对添加不同水平SBP[0(对照组)、8%(8SBP组)、16%(16SBP组)、24%(24SBP组)]的全混合日粮72 h产气量、瘤胃液pH、氨态氮(NH3-N)、挥发性脂肪酸(VFA)、微生物蛋白(MCP)浓度以及营养物质有效降解率进行测定。结果表明:1)16SBP和24SBP组的72 h产气量和潜在产气量均显著高于对照组(P <0.05),SBP的添加对产气速率没有产生显著的影响(P>0.05)。2)发酵液pH随着SBP添加水平的提高而降低,24SBP组pH最低,显著低于其他各组(P<0.05);与对照组相比,各试验组发酵液NH3-N和M CP浓度都有上升的趋势,但差异不显著(P>0.05);甲烷(CH4)和二氧化碳(CO2)产量也有所变化,但没有产生显著差异(P>0.05);试验组乙酸和总VFA浓度均显著高于对照组(P<0.05)。3)与对照组相比,16SBP和24SBP组干物质(DM)、酸性洗涤纤维(NDF)有效降解率显著提高(P <0.05),8SBP和16SBP组粗蛋白质(CP)有效降解率显著提高(P<0.05)。综上,饲粮中添加SBP改善了体外发酵并且提高了营养物质的降解率,但饲粮中最适SBP添加水平还需要进一步通过试验确定。     

Effect of extruding the cereal and/or the legume protein supplement of a compound feed on in vitro ruminal nutrient digestion and nitrogen metabolism

An experiment was performed to evaluate the effect of extruding the cereal and/or the protein supplement of a compound feed for intensively reared calves on ruminal N metabolism using an in vitro culture system. A conventional compound feed was produced without extruding [treatment non-extruded (NE)], with the cereal blend extruded (CE), with the protein blend extruded (PE) and with both cereal and protein blends extruded (CPE). Four experimental diets, consisted of 0.90 of each experimental compound feed and 0.10 barley straw were assessed using dual-flow continuous-culture fermenters. (15)N infusion as ammonia sulphate was used to label the microbial population. Average NH(3) concentration in fermenter effluents ranged from 270 mg/l with diet NE to 69 mg/l for diet CPE (p < 0.05) and volatile fatty acid concentrations ranged from 161 mm in diet PE to 130 mm in diet CPE (p < 0.05). Diets PE and CPE showed a lower true organic matter degradability (49.5% and 48.2%) than NE and CE (52.8% and 52.2%). Non-ammonia nitrogen flow in effluents was highest on diet CPE, intermediate on diets CE and PE and lowest on diet NE (p < 0.01), reflecting the differences in dietary N flow and dietary protein degradability (71.2%, 63.7%, 61.2% and 50.0%, respectively, for NE, CE, PE, CPE; p < 0.001). In contrast, microbial protein synthesis efficiency was lower for treatments including the cereal blend extruded, although the resulted differences were only significant (p < 0.001) for CPE diet.     

稻草与不同饲料混合在体外消化率上的组合效应研究

以体外干物质消化率(IVDMD)对鲁梅克斯K-1(Rumex patientia,RP)、紫云英(Astragalus sinicus,AS)、高丹草(Sorghum hybrid Sudangrass,SHS)、苏丹草(Sorghumsudanense,SS)、矮象草(Pennisetumpurputeumcv.mott,PPM)、苜蓿(Medicagosativa,MS)、木薯干草(CH)、稻草(RS)、氨化稻草(ARS)与木薯渣(CR)的品质进行了评定。IVDMD(%)自高到低的排序为:CR(77.63)、RP(61.32)、MS(55.26)、AS(54.91)、CH(52.97)、SHS(40.24)、PPM(38.70)、ARS(36.88)、SS(34.15)、RS(26.63)。除AS与MS外,各种饲料间的IVDMD差异显著(P0.05)。本研究将组合效应值(AE)定义为混合饲料实测IVDMD与各单个饲料IVDMD加权和值之差。分别以RS、ARS作为低、中等品质基础秸秆饲料,再分别添补RP、AS、SHS、SS、PPM、MS与CH(RS还补饲ARS),共6个组合。结果表明,任一组合均观察到正组合效应,以添补MS的最大;CH作为添补料其效果要好于禾本科牧草,与豆科牧草相似;对低质秸秆基础饲料的补饲较对中等品质的组合效应明显。     

Effect of field pea (Pisum sativum L.) level on intake,digestion, ruminal fermentation and in vitro gas production in sheep fed maintenance diets

The objective of this study was the characterization of the nutritive value, ruminal fermentation and nutrient digestibility of field pea (Pisum sativum L.) hay (FPH) by‐product through in situ, in vitro and in vivo tests. A FPH diet was administered ad libitum to four sheep (live weight (LW) 38.0 ± 2.0 kg) at four inclusion levels (0, 25, 50 and 75%) over a conventional sorghum grain/oat straw ration in a 4 × 4 Latin square design. The in situ degradability of FPH was 67% dry matter (DM), 71% crude protein and 66% neutral detergent fiber (NDF). The inclusion of FPH did not affect (P ≥ 0.05) the DM (61 ± 0.4 g/LW^0.75/day) and organic matter (OM) intake (56 ± 0.7 g/LW^0.75/day). Total DM digestibility (68 ± 2.5%), OM (70 ± 3%), and NDF (60 ± 3%), were not different (P ≥ 0.05) between control and FPH inclusion diets. The diet had no effect on ruminal pH, ruminal ammonia concentration, total and individual volatile fatty acids. The chemical composition and sheep intake behavior indicate that FPH by‐product is medium quality forage when incorporated in maintenance rations.     

不同处理对王草青贮品质及其体外消化率的影响

 试验以热研4号王草为青贮原料,研究不同处理对王草青贮饲料发酵品质和体外消化率的影响,共设置鲜草直接青贮(C)、半干青贮(W)、添加粗饲料降解剂(3%,6%)(BA)、甲酸(FA)、蔗糖(S)等6个处理。结果表明：王草直接青贮品质不高;晾晒和添加粗饲料降解剂、甲酸、蔗糖等处理能显著降低pH值和提高乳酸含量,两个水平的粗饲料降解剂无显著差异;添加蔗糖处理能极显著降低pH值、提高乳酸含量和体外消化率。综合考虑,晾晒和添加剂处理能明显改善青贮品质和体外消化率,其中半干王草添加2%蔗糖效果最好。     

Effects of calcium oxide treatment at varying moisture concentrations on the chemical composition,in situ degradability,in vitro digestibility and gas production kinetics of anaerobically stored corn stover

The objective of this study was to determine the optimum conditions for calcium oxide (CaO) treatment of anaerobically stored corn stover by in situ and in vitro methods. Four ruminally cannulated, non‐lactating, non‐pregnant Holstein cows were used to determine the in situ effective degradabilities of dry matter (ISDMD), organic matter (ISOMD), neutral detergent fibre (ISNDFD), in vitro organic matter disappearance (IVOMD) and gas production in 72 h (GP_72h) of corn stover. A completely randomized design involving a 3 × 3 factorial arrangement was adopted. Ground corn stover was treated with different levels of CaO (3%, 5% and 7% of dry stover) at varying moisture contents (40%, 50% and 60%) and stored under anaerobic conditions for 15 days before analysis. Compared with untreated corn stover, the CaO‐treated stover had increased ash and calcium (Ca) contents but decreased aNDF and OM contents. The moisture content, CaO level and their interaction affected (p < 0.01) the content of aNDF, ash and OM, and the ratio of aNDF/OM. The greatest ISDMD, ISOMD and ISNDFD were observed when stover was treated with 7% CaO and 60% moisture, while no differences (p > 0.01) in these in situ degradability parameters were observed between the stover treated with 5% CaO at 60% moisture content and those treated with 7% CaO at 60% moisture content. Corn stover treated with 5% CaO at 50% moisture had the maximum IVOMD and GP_72 h among the treatments, and there was no difference (p > 0.01) between 50% and 60% moisture. Results from this study suggested that 5% CaO applied at 60% moisture could be an effective and economical treatment combination.     

干旱胁迫对新疆三个优势牧草种的光合特性与水分利用效率的影响

通过盆栽试验,研究了不同土壤含水量条件下(田间持水量的80%、60%和30%)新疆地区天然草地3个优势牧草种(无芒雀麦、草地早熟禾和鸭茅)叶片的光合生理特性及叶片和单株水分利用效率,以探讨不同优势牧草种对干旱胁迫的适应机制。结果表明:随干旱胁迫加剧,3个牧草种的C_i日平均值呈上升趋势,G_s、P_n、T_r 、P_n/C_i日平均值和日平均耗水量呈下降趋势,但物种间各参数变幅存在差异;草地早熟禾日平均生物产量呈明显下降趋势(P<0.05),鸭茅和无芒雀麦无明显变化(P>0.05);鸭茅的WUE_i日平均值和WUE_ET无显著变化(P>0.05),无芒雀麦和草地早熟禾呈明显下降趋势(P<0.05)。3个牧草种的WUE_ET均与其日平均累积生物量显著正相关(P<0.05),草地早熟禾的WUE_ET与其T_r日平均值和日平均耗水量亦显著正相关(P<0.05)。3个牧草种的叶片和单株水分利用效率随土壤含水量下降具有不同的变化趋势,预示着3个物种对干旱生境的适应不仅取决于其水分利用效率的大小,还可能与其生物学特性和生活史策略有关。