牛至精油对绵羊瘤胃体外养分降解率、发酵特性及CH4产量的影响

试验旨在研究牛至精油对绵羊瘤胃体外养分降解率、发酵特性及CH₄产量的影响。采用单因素完全随机试验设计,在培养液中分别添加0(CON)、100(EO₁)、400(EO₂)、700(EO₃)和1000 mg·L^-1(EO₄)牛至精油,每组4个重复。发酵48 h后测定养分降解率、发酵参数及不同时间总产气量和CH₄产量。结果表明:1)与CON组相比,干物质降解率、粗蛋白降解率、中性洗涤纤维降解率在EO₁组中均显著升高(P<0.05),在EO₄组中均显著降低(P<0.05),EO₂组中均无显著差异(P>0.05),干物质降解率在EO₃组中显著降低(P<0.05),添加牛至精油对酸性洗涤纤维降解率(ADFD)无显著影响(P>0.05);2)EO₁组pH最低,而总挥发性脂肪酸(TVFA)、丙酸浓度最高,且乙酸浓度显著高于EO₂、EO₃和EO₄(P<0.05),但乙酸/总挥发性脂肪酸显著低于EO₃、EO₄组(P<0.05),乙酸/丙酸显著低于CON组(P<0.05)。与CON组相比,牛至精油组丁酸、丁酸/总挥发性脂肪酸和氨氮浓度显著降低(P<0.05);3)发酵36 h后,总产气量、甲烷产量均随牛至精油的添加而逐渐降低,与CON组相比,EO₁组发酵18~48 h总产气量显著降低(P<0.05),EO₂、EO₃和EO₄组总产气量、CH₄产量在发酵18 h后均显著降低(P<0.05),EO₄组甲烷百分比在发酵12~36 h显著降低(P<0.05)。综上所述,在绵羊瘤胃体外培养液中添加牛至精油能够提高饲粮养分降解率,调控瘤胃发酵,降低总产气量和甲烷产量,体外条件下添加量不应高于100 mg·L^-1。     

同/异型发酵乳酸菌对全株玉米青贮营养成分和瘤胃降解特征的影响

以新饲玉10号全株青贮玉米为研究材料,旨在探究同/异型发酵乳酸菌对其主要营养成分和瘤胃降解率特征的影响。采用真空袋法调制青贮,共设计4个发酵处理,分别为不添加任何菌剂(CK);复合同型发酵乳酸菌植物乳杆菌+戊糖片球菌(T),添加量为1∶1,1×10^5 cfu·g^-1;异型发酵乳酸菌布氏乳杆菌(Y),添加量为1×10^5 cfu·g^-1;复合同、异型发酵乳酸菌(TY),添加量为1∶1∶1,1×10^5 cfu·g^-1。通过对模拟开窖60 d主要营养成分和绵羊瘤胃降解特征参数的分析。结果表明:干物质(DM)、中/酸性洗涤纤维(N/ADF)、可溶性碳水化合物和粗脂肪含量最优均为Y处理,粗蛋白和淀粉含量各试验处理均极显著高于CK处理(P<0.01),粗灰分含量最高为CK处理。DM和NDF有效降解率按高低排序均为T和Y处理>CK和TY处理(P<0.01)。有机物(OM)有效降解率最高为Y处理(P=0.003)。各处理ADF有效降解率间差异不显著(P>0.05)。说明玉米青贮中Y处理可显著增加开窖60 d时各营养成分含量(粗灰分除外),且显著提高DM和OM有效降解率,TY处理可显著提高NDF有效降解率。综合营养成分和有效降解率12项指标进行隶属函数评价,各处理按优劣排序为:Y处理>T处理>TY处理>CK处理。     

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.     

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。     

添加蔗糖对大麦青贮品质及中、酸性洗涤纤维瘤胃降解率的影响

本试验研究了添加蔗糖 (可溶性糖 )对大麦青贮品质及中性洗涤纤维 (NDF)和酸性洗涤纤维 (ADF)瘤胃降解率的影响。试验采用随机分组设计进行 ,在刚收获及收获后经过 1 8和 30小时萎蔫的整株大麦 (干物质含量分别为 30 33%、4 0 55%和 4 8 95% )青贮料中 ,分别加入 0、1 %、1 5%和 2 %的蔗糖。结果表明 ,添加蔗糖对青贮大麦的感官质量没有明显影响。与对照组相比 ,加糖使青贮发酵 2 0天时的pH值极显著降低 (P <0 0 1 ) ,但对最终 ( 1 30天 )的pH值没有显著影响 (P >0 0 5)。加糖提高了青贮大麦的乳酸含量 (P <0 0 5)。对氨态氮影响不明显 (P >0 0 5)。用尼龙袋技术测定青贮料中、酸性洗涤纤维的瘤胃降解率 ,结果表明 ,试验组与对照组之间均无显著差异 (P >0 0 5)。     

玉米油对秸秆瘤胃降解率与肉牛日粮消化率的影响

头装有瘤胃瘘管的成年杂交黄年,饲以加入０．４％或８％玉米油的稻划和精料混合料９２：１）。用尼龙袋技术分别测定羊草、麦秸和稻草的干物质（ＤＭ）和中性洗涤纤维（ＤＮＦ）４８ｈ和７２ｈ的瘤胃降解率和日粮ＤＭ,ＮＤＦ和粗蛋白（ＣＰ）的全消化道消化率。结果表明,随着玉米油添加量的增加,稻草、羊草和麦秸的ＤＭ用ＮＤＦ瘤胃降解率均有下降的趋势,但只有添加８％玉米油时稻草７２ｈ的ＮＤＦ瘤胃降解率和添加４％或８％玉米油时麦秸４８ｈ的ＮＤＦ瘤胃降解率差异达到了显著水平（Ｐ〈０．０５）。日粮中添加８％以下的玉米油对日粮ＤＭ,ＣＰ,ＮＤＦ的全消化道消化主没有影响（Ｐ〉０．０５０。这表明肉牛后部消化道对玉米油的影响可能有补偿作用。本试验的结论是,向肉牛或奶牛日粮中添加８％以下的玉米油对饲料消化率没有影响,但添加与否需根据实际经济效益确定     

Effects of yeast and yeast cell wall polysaccharides supplementation on beef cattle growth performance,rumen microbial populations and lipopolysaccharides production

This experiment was conducted to investigate the effects of live yeast and yeast cell wall polysaccharides on growth performance, rumen function and plasma lipopolysaccharides(LPS) content and immunity parameters of beef cattle. Forty Qinchuan cattle were randomly assigned to one of four treatments with 10 replicates in each treatment. The dietary treatments were: control diet(CTR), CTR supplemented with 1 g live yeast(2×1010 live cell g–1 per cattle per day(YST1), CTR supplemented with 2 g live yeast per cattle per day(YST2) and CTR supplemented with 20 g of yeast cell wall polysaccharides(30.0%≤β-glucan≤35.0%, and 28.0%≤mannanoligosaccharide≤32.0%) per cattle per day(YCW). The average daily gain was higher(P=0.023) and feed conversion ratio was lower(P=0.042) for the YST2 than the CTR. The digestibility of neutral detergent fiber(P=0.039) and acid detergent fiber(P=0.016) were higher in yeast supplemented groups. The acetic acid:propionic acid of the YST2 was lower compared with the CTR(P=0.033). Plasma LPS(P=0.032), acute phase protein haptoglobin(P=0.033), plasma amyloid A(P=0.015) and histamine(P=0.038) were lower in the YST2 compared with the CTR. The copies of fibrolytic microbial populations such as Fibrobacter succinogenes S85, Ruminococcus albus 7 and Ruminococcus flavefaciens FD-1 of the YST2 were higher(P0.001), while the copies of typical lactate producing bacteria Streptococcus bovis JB1 was lower(P0.001) compared with the CTR. Little differences were observed between the CTR, YST1 and YCW in growth performance, ruminal fermentation characteristics, microbial populations, immunity indices and total tract nutrient digestibility. It is concluded that the YST2 could promote fibrolytic microbial populations, decrease starch-utilizing bacteria, reduce LPS production in the rumen and LPS absorption into plasma and decrease inflammatory parameters, which can lead to an improvement in growth performance in beef cattle.     

应用CNCPS-S模型预测全混合日粮碳水化合物绵羊瘤胃降解率的研究

本研究旨在应用康奈尔绵羊净碳水化合物和蛋白质体系（Cornell sheep net carbohydrate and protein system，CNCPS-S）的瘤胃降解预测模型预测日粮碳水化合物（CHO）瘤胃有效降解率，并实测验证CNCPS-S模型预测值的准确性。选取3只安装瘤胃瘘管、体重分别为（38.03±1.56）kg的哈萨克公羊作为试验动物，配制3种精粗比分别为30：70、35：65、40：60的全混合日粮（TMR），利用瘤胃灌注试验和尼龙袋试验实测3种日粮CHO的瘤胃外流速度（Kp）和降解率，同时利用CNCPS-S模型预测3种日粮CHO的Kp与降解率，对CHO的降解率预测值和实测值进行线性回归分析，评价模型预测的准确性。结果表明：3种TMR的瘤胃食糜Kp随精料比例增加而依次升高（P<0.01），分别为3.58%/h、3.83%/h、4.05%/h，据此计算而得的CHO的降解率分别为42.7%、43.1%、42.3%（P>0.05）；随精料比例的增加，3种TMR的瘤胃食糜Kp的模型预测值依次升高（P>0.05），分别为1.62%/h、1.63%/h、1.64%/h，CHO瘤胃降解率的预测值分别为39.5%、39.1%、39.6%（P>0.05）；3种日粮CHO瘤胃降解率的预测值与实测值之间的平均偏差比较小（≤ 4 g/100 g CHO），相关性较高（R² ≥ 0.86），均方根误差也较低（RMSE ≤ 1.93 g/100 g CHO）。以上结果说明，CNCPS-S瘤胃降解预测模型对日粮CHO的降解率具有较好的预测能力。     

瘤胃保护性赖氨酸过瘤胃效果的评价

本研究采用瘤胃尼龙袋法和运动尼龙袋法测定了不同比例棕榈油脂肪粉包被赖氨酸的瘤胃降解率及小肠释放率,结果发现:以30%、40%、50%和60%的棕榈油脂肪粉对赖氨酸进行包被而制备的RPLys-Ⅰ、RPLys-Ⅱ、RPLys-Ⅲ和RPLys-Ⅳ,48 h瘤胃降解率依次为62.42%、55.12%、50.34%和47.21%;24h小肠消失率依次为80.27%、67.05%、64.92%和54.80%。综合分析认为,棕榈油脂肪粉包被比例以50%为宜。