| Gamma-aminobutyric acid (GABA) is a kind of nonprotein amino acid that widely exists in nature,and it has the functions of inhibitory neurotransmitter and formed by glutamate decarboxylase (GAD) catalyse glutamic acid.GABA participate in the metabolism of varieties of activities and has functions to animals such as antist-ress,regulate hormone secretion,improve the carcass quality and improve reproductive performance and so on.Lactic acid bacteria is a internationally recognized as beneficial bacteria that containing GAD,the use of Lactic acid bacteria and its GAD for enrichment of GABA is an important way of production.The main purpose of this study was to screening of Lactic acid bacteria with high GABA ability and using the GAD to the production of GABA for livestock feed additives and the GABA in the yanbian yellow cattle,applied to theoretical basis for the application of the lactic acid bacteria,the production of feed additives which rich in GABA and the the application of yanbian yellow cattle in using GABA.The research of this paper mainly includes the following several aspects:1.The screening of highly yield y-aminobutyric acid producing Lactic acid bacteria and preliminary identificationScreening of y-aminobutyric acid producing Lactic acid bacteria from the hot cabbage,sour pickled cabbage,yogurt with gradient dilution method and paper chrom-atography in this chapter,using the method of HPLC for quantitative determination of concentration of GABA of the fermented liquid and preliminary identification of the Lactic acid bacteria of high GABA synthesis ability,the results show that Lactic acid bacteria B1 from sour pickled cabbage has the best high capacity of producing GABA and can reached 3.121 g/L.2.Study on the optimal conditions of the y-aminobutyric acid fermentation by Lactobacillus brevis using rice branLactobacillus were used to ferment rice bran as the low-cost agricultural and sideline products.Study of single factor fermentation temperature and time、 the amount of bacterium> the concentration of PLP and Cacl2 influence the GABA content in the rice bran fermented liquid.On the basis of single factor experiment with orthog-gonal analysis method to optimize the fermentation conditions of rice bran,determine the optimal conditions for lactic acid bacteria fermentation rice bran enrichment of GABA.The GABA content in the fermented liquid reach to 335mg/100g under the conditions of the time of fermentation is 24h、the amount of bacterium is 3.5%、the concentration of PLP is 0.1mmol/L、the concentration of Cacl2 is 1.5mmol/L.3.The research of activities of the properties of the glutamic acid decarboxylase and its application in feed additive productionIn this chapter,studied the relationship between GAD activity produced by Lactic acid bacteria B1 and the different factors, containing its temperature,stability,pH,PLP and the effect of metal ions and chemical substances,research the Vmax and Km of the GAD,determine the optimum temperature,optimal pH and so on when GAD has the best activity.Then using the decarboxylation reaction of GAD and L-glutamic acid for producing the GABA of feed additives.The results show that the optimal reaction temperature of the GAD of the Lactic acid bacteriaB1 is 40℃ and it has good stability within the range 30 to 50℃;the optimal reaction pH of the GAD is 4.5 and has good stability within the range 3.5 to 5.5;when the concentration of PLP and VB6 reach 0.05mmol/L,the GAD has the best activity.There were greatly influences on the activity of GAD by metal ions and chemical substances,such as Ca2+、Mg2+、Mn2+ can activate the enzyme activation and SDS、I-、whereas Ag+、Cl-、CH3COOH、EDTA can inhibit the enzyme activation;the Km of the GAD to glutamic acid was 0.0601mmol/L,Vmax=1.98μmol/min.Using the characteristics of the GAD for the production of the feed additives GABA,the test feasibility is strong,the content of GABA can reach 8.96%(w/w).4. The study of stability of gamma-aminobutyric acid and the affected of it on the intestinal digestibility、enocrine hormone、immune index、oxidation resistance and the influence of routine blood in yanbian yellow cattle4.1 The study of coated GABA by-pass rumen characteristicFor the coated GABA of two different material with rumen degradation rate in vivo and release after rumen in vitro,found the degradation rate in the rumen were 20.97% and 24.91% respectively at the time of 24h, release rate after the rumen were above 90% at the time of 12h. After the comprehensive comparison of the conclusion: the coated GABA with palmitic acid is more suitable for using in the yanbian yellow cattle.4.2 The affected of GABA on the intestinal digestibility、enocrine hormone、immune index、oxidation resistance and the influence of routine blood in yanbian yellow cattleThrough add coated GABA to the based diet of yanbian yellow cattle,the results show that it had no effect on the rate of intestinal digestibility.Compared with the control group,for cortisol,experimental group Ⅰ had significantly reduced the concentr ation of COR (P< 0.05), experimental group Ⅱ had significantly reduced the concentration of COR (P<0.01) and experiment II significantly below experiment I(P <0.05);For ACTH experimental group Ⅰ and experimental group Ⅱ had significantly reduced the concentration of ACTH;For the immune index,experiment group Ⅰ and experiment group Ⅱ had significantly increased the concentration of 1g A and 1g G (P <0.01),but there was no effect on the concentration of 1g M (P>0.05) experimental group Ⅰ and experimental group Ⅱ had significantly increased the concentration of IL-2 (P<0.05);For oxidation resistance,experimental group Ⅰ and experimental group Ⅱ had significantly decreased the concentration of MDA (P<0.05), significantly increased the activity of GSH-Px (P<0.01) and the activity of experimental Ⅱ significantly greater than it of experimental Ⅰ (P<0.05) and there was no influence on the activity of SOD (P> 0.05);For routine blood,experimental group Ⅰ and experimental group Ⅱ had significantly increased MCV (P< 0.05),significantly increased the number of PLT (P<0.01) and the number of experimental group Ⅱ had significantly greater than experimental group Ⅰ (P<0.05).In this experimental,the supplement GABA of appropriate level is 55g/d/head. |
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