| 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 inâ…¤g 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(Groupâ… =5.37%, Groupâ…¡=3.00%, Groupâ…¢=5.77%, Groupâ…£= 3.03%, Groupâ…¤= 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.
|
PDF Full Text Request