【作者】 照日格图；

【导师】 敖长金；

【作者基本信息】 内蒙古农业大学 ， 动物营养与饲料科学， 2010， 博士

【摘要】 本论文利用体外批次培养法,研究了奶牛三种不同品质粗饲料日粮及添加异位酸对日粮体外发酵效果、纤维物质降解率、微生物菌群、纤维素酶活、氨基酸产量等的影响,并进一步探讨了粗饲料品质及添加异位酸对日粮体外发酵水平、纤维物质降解率和微生物菌群的影响和机理。在此基础上通过饲养试验进一步研究了异位酸对泌乳奶牛营养代谢和生产性能的影响。体外试验选用体况良好、体重和胎次相近的安装有永久性瘤胃瘘管的3头荷斯坦奶牛,以供采集瘤胃液。以GI为指标对粗饲料品质进行测定,然后固定精粗比为45:55条件下配制三种混合日粮,形成含高GI粗料日粮组(1号料,粗料GI=2.89 MJ)、含中GI粗料日粮组(2号料,粗料GI=1.73 MJ)和含低GI粗料日粮组(3号料,粗料GI=0.65 MJ)。结果表明:1.不同品质单一粗饲料(苜蓿、羊草、玉米秸秆、青贮)对日粮体外发酵效果有显著影响(p<0.05),随着粗料品质的提高培养液NH3-N、VFAs、BCP浓度和产气量显著提高(p<0.05),但对培养液pH值影响较小,各时间点pH值均高于6.20,其中羊草组培养液pH值一直保持较高水平,秸秆组最低,乙/丙比例大小顺序为羊草>玉米秸秆>苜蓿>青贮;当苜蓿、羊草、玉米秸秆以一定比例与青贮混合培养时,对日粮体外发酵效果能够起到互补和整体改善作用。2.精粗比例相同(45:55)、能量和蛋白水平一致情况下,三种混合日粮在体外培养时,粗料品质好的混合日粮培养液NH3-N、VFAs、BCP和气体产量显著高于其它组(p<0.05),乙/丙比例恰好相反。pH值大小顺序为2号料>1号料>3号料,但均值差异不显著(p>0.05),各时间点pH值均大于6.10。另外,混合日粮培养液VFA和BCP明显高于单一和混合粗饲料,而pH值、乙酸丙酸比例有所下降。3.本试验用三种日粮中添加单一和混合异位酸时,培养液NH3-N、VFAs、BCP浓度和产气量显著提高(p<0.05),其中混合异位酸的添加效果优于其它组,pH值、乙/丙比例有所下降,但其平均值差异不显著(p>0.05)。另外,对粗料品质较差的2号料和3号料体外发酵作用效果更为明显。4.粗料以苜蓿、羊草和玉米秸秆为主的三种日粮中,戊酸最适添加量分别为5.00mg/g、5.00mg/g和5.00mg/g;异戊酸最适添加量分别为5.00mg/g、5.00mg/g和5.00mg/g;异丁酸最适添加量分别为2.50mg/g、2.50mg/g和5.00mg/g;2-甲基丁酸最适添加量分别为1.25mg/g、1.25mg/g和5.00mg/g。5.粗饲料品质对日粮体外发酵DM、NDF降解率有显著影响(P<0.05),粗饲料品质好的日粮DM、NDF降解率高,对ADF降解率没有显著影响(P>0.05);添加单一和混合异位酸使不同品质粗饲料日粮DM、NDF、ADF降解率显著提高(P<0.05),尤其是培养后12h和24h时纤维物质的降解率有较大幅度的提高,对低质粗饲料日粮DM、NDF、ADF降解率提高更为明显,其中混合异位酸添加组效果优于其它组。6.随着粗饲料品质的提高CMCase、果胶酶和木聚糖酶等三种酶活性显著提高(P<0.05) ;粗饲料品质对FPA、葡萄糖苷酶活性没有产生显著影响(P>0.05);FPA、CMCase、葡萄糖苷酶和果胶酶酶活峰值出现在培养后6h,木聚糖酶活峰值出现在培养后9h;单一或混合异位酸的添加使三种日粮培养液五种酶活显著提高(P<0.05),其中混合异位酸的添加效果更为明显。7.随着粗饲料品质的提高细菌、纤维分解菌数量显著增加(p<O.05),真菌数量显著下降(p<O.05),对原虫数量无显著影响(p>0.05);细菌、纤维分解菌和原虫数量峰值出现在培养后6h,真菌数量峰值出现在培养后9h;添加单一和混合异位酸能够显著增加培养液真菌、细菌、纤维分解菌和原虫数量(p<O.05),其中添加混合异位酸组优于其它组。8.随着粗饲料品质的提高培养液BCAA、EAA、TAA产量显著提高(P<0.05);添加单一和混合异位酸使三种日粮培养液相应BCAA、EAA浓度显著提高(P<0.05),其中混合异位酸的添加效果优于其它组。9.奶牛日粮中添加单一或混合异位酸时,血清Ins呈下降趋势(P>0.05);FT3、FT4呈下降趋势,并在试验第30d时Ⅴ组(混合组)的FT3降低幅度达到极显著水平(P<0.01);PRL、GH有所提高(P>0.05),TP显著提高(P<0.05),其中混合酸异位酸添加组由于其它组;对COR、TG、ALT几乎没有影响;AST、GGT、GLU有所下降(p>0.05);BUN显著降低(P<0.05),其中混合酸异位酸添加组最低;有提高血清必需氨基酸中支链氨基酸比例的趋势(P>0.05)。10.异位酸的添加对产奶量的提高较明显,各试验组产奶量分别提高(Ⅰ组=5.37%、Ⅱ组=3.00%、Ⅲ组=5.77%、Ⅳ组=3.03%、Ⅴ组=10.34%);使乳脂率、乳蛋白率、总固形物和非脂乳固体含量有所提高(P>0.05),对乳糖含量几乎没有影响;显著提高乳中Gly、Ala、Cys浓度(P<0.05),使相应支链氨基酸浓度有所提高(P>0.05),对其余氨基酸没有影响,说明乳中氨基酸浓度基本稳定。更多还原

【Abstract】 In this study, based on in vitro batch incubation to investigated the effect of three kinds of different quality of dietary forage and isoacids adding on fermentation level of ration, degradation rate of fibre, microbial population, cellulase activity, and the production of amino acid. And further discussed the influence of forage quality and isoacids adding on ferment level of ration, the degradation rate of fibre and microbial population in vitro, and its mechanism. Finally studied the effect of isoacids on the nutrient metabolism and productive performance in dairy cow by feeding experiment. Three Holstein cows with ruminal cannula which were the same health status, body weight, birthorder were selected to offering the ruminal fluid.Grading index as target evaluate the roughage quality, then formulate the 3 kinds of ration under the condition of concentrate to roughage ratio was 45:55, forming higher grading index ration group (ration No.1, GI = 2.89 MJ), middle grading index ration group (ration No.2, GI = 1.73 MJ) and low grading index ration group (ration No.3, GI = 0.65 MJ). The results showed that:1. The ferment of vitro was affected significantly by different quality of single forage which were Alfalfa hay,Chinese wildrye,Corn straw and Corn silage (p<0.05). The density of NH3-N,VFAs,BCP and the cumulative of gas production was significantly increased with the improvement of the forage quality(p<0.05).But there was no significantly impact on PH value. In each time, PH value exceed to 6.20.Among them,PH value of Chinese wildrye was higher constantly and that of corn straw was the lowest .The order in PH value of A/P was Chinese wildrye>Corn straw>Alfalfa hay>Corn silage; When a certain proportion of Alfalfa hay, Chinese wildrye, Corn straw mixed cultured with Corn silage, there was complementary and overall improvement on the effect of ferment in Vitro.2. Under the same percentage of Crude (45:55), in the same circumstances of energy and protein level, NH3-N,VFAs,BCP and gas production were significantly higher than other groups among the mixed dietaries of good quality forage when three kinds of mixed dietary was cultivated in vitro (p<0.05).The proportion of A/P was contrary. The order of PH value was forage No.2>forage No.1>forage No.3, but the difference was little. The each time of PH value was higher than 6.10.In addition , the mixed dietaries of VFAs and BCP were significantly higher than single forage and mixed forage , however, the pH value and the A/P were in decline .3. In this experiment, VFAs, BCP, gas production, NH3-N concentration increased significantly by adding single and mixed Isovalerate to three kinds of different quality of dietary forage(p<0.05).Among them ,it was that adding mixed Isovalerate which was better than other groups, which made the pH value and the A/P declined, but from the average value view , there was no significant differences (p>0.05). In addition, There was more obvious effect on ferment of inferior quality which were forage No.3 and forage No.2 by adding single Isovalerate and mixed Isovalerate .4. The optimum supplement of Valerate was respectively 5.00mg/g,5.00mg/g, 5.00mg/g in the three kinds of dietaries which included Alfalfa hay , Chinese wildrye , Corn straw;that of Isovalerate was respectively 5.00mg/g,5.00mg/g and 5.00mg/g;that of Isobutyrate was respectively 2.50mg/g,2.50mg/g , 5.00mg/g;that of 2-methyl Butyrate was respectively 1.25mg/g,1.25mg/g , 5.00mg/g by terms.5. Degradation rate of DM,NDF ferment in vitro was influenced significantly by forage quality(P<0.05). The degradation rate of DM and NDF in good quality forage were high. There was no significant effect on the degradation rate of the ADF (P>0.05). The degradation rate of DM,NDF,ADF increased significantly by adding single Isovalerate and mixed Isovalerat(ep<0.05).In particular, the degradation rate of fiberic material was more greatly enhanced after 12h and 24h’s training . The degradation rate of the low-quality forage such as DM,NDF ,ADF improved even more obvious. Among them,the group with adding mixed Isovalerate was better than other groups.6. The activity of CM Case,pectic enzyme , xylanase were influenced significantly by forage quality(P<0.05). It was that these three kinds of enzymic activity had an ascendant tendency with the improvement of forage quality;there was no significant effect on FPA activity and glucose indican enzyme activity(P>0.05); the peak value of CMCase activity,pectic enzyme activity,FPA activity , glucose indican enzyme activity was showed after 6h,however ,the peak value of xylanase activity was showed after 9h.Five kinds of enzymic activities and three kinds of forages were increased significantly by adding single Isovalerate and mixed Isovalerate(p < 0.05).Among them,it was that adding mixed Isovalerate was better.7. Fungi,bacteria ,cellulolytic bacteria were influenced significantly by forage quality (P<0.05);but there was no significant effect on protozoa quantities (P>0.05).It was that quantities of the bacteria and cellulolytic bacteria had an ascendant tendency when dietary forage quality increased. But the quantities of Fungi had a descendant tendency. Forage No.2 had the largest number of protozoa, but forage No.1 had the minimum number of protozoa . The number of protozoa in forage No.3 was in middle.The peak value of bacteria,cellulolytic bacteria ,protozoa quantities was showed after 6h; the peak value of Fungi quantities was showed after 9h. In this experiment, the quantities of Fungi,bacteria,cellulolytic bacteria, protozoa increased significantly by adding single Isovalerate and mixed Isovalerate to three kinds of dietaries(p<0.05).Among them, adding mixed Isovalerate was better than other groups. In particular, forage No.3 was more obvious than the other two kinds of forages on the raise of protozoa quantities.8. The production of BCAA,EAA,TAA were increased significantly with the improvement of forage quality(P<0.05).The density of Essential a Amino Acid, Branched Chain Amino Acid was increased significantly by adding single and mixed Isovalerate to three kinds of dietaries(p<0.05).In which,it was that adding mixed Isovalerate was better.9. The concentration of Ins had a descendant tendency when adding single and mixed Isovalerate to dietary(P>0.05);the density of FT3 and FT4 had a descendant tendency, moreover, when the test was 30d ,the concentration of FT3 decreased extremely significant inⅤg roup(P<0.01); the concentration of PRL and GH was increased, but there was no significant differences(P>0.05); the concentration of TP increased significantly (p<0.05), in which,it was that the group adding mixed Isovalerate was the highest.There was no significant effect on the concentration of COR,TG,ALT(p>0.05); the concentration of AST,GGT,GLU had an descendant tendency , but there was no significant differences(P>0.05); the concentration of BUN decreased significantly(p<0.05),among them, the concentration of BUN was the lowest in adding mixed Isovalerate group; it had a certain effect on the constitution of Essential Amino Acids profile of Serum,the rate of Branched Chain Amino Acid increased in Essential Amino Acids.10. there was an obvious increase on milk production,the milk production of each test group improved respectively(GroupⅠ=5.37%, GroupⅡ=3.00%, GroupⅢ=5.77%, GroupⅣ= 3.03%, GroupⅤ= 10.34%);the ratio of milk fat and milk protein and centents of TS and SNF were improved(P>0.05); there was almost no effect on the content of milk sugar;the concentration of Gly,Ala,Cys were increased significantly(P<0.05);the density of Branched Chain Amino Acid increased(P>0.05);there were no effect in the rest of the amino acid concentrations,it was to say that the concentration of amino acids was basically stable in milk.更多还原