Determination Of Enzymatic Activity Offeeding Microorganisms And Study On Thenutritional Quality Of Fermented Jujube Feed

In this test,Bacillus subtilis,Lactobacillus plantarum,and Saccharomyces cerevisiae isolated from corn stalks were constructed as a compound microbial inoculum.The optimal fermentation conditions were determined by measuring the enzymatic activity and growth characteristics of each strain for fermentation of red date In order to improve its nutritional value,reduce the content of harmful substances such as toxins,and improve its feed quality.Experiment 1 Determination of the Enzymatic Activity of Fermented Jujube Feed Compound Bacterium and Exploration of Optimum Growth ConditionsIn this test,a qualitative and quantitative method was used to select cellulose-Congo red screening media,combined with the determination of cellulase activity and acid-producing bacteriostatic activity,to investigate the secretion of cellulase and woody substance to Bacillus subtilis under different temperature and p H conditions.The influence of enzyme activity and acid-producing ability of plant lactobacillus,and the determination of the growth curve of each strain,fully grasp the optimal secreting enzyme and acid-producing conditions of each strain,and determine the optimal growth inoculation time.The results show:After dilution and plating,the viable counts of seed strains of each strain were greater than 9*10~9cfu/m;the optimal growth and inoculation time for Bacillus subtilis,plant lactic acid bacteria,and Saccharomyces cerevisiae strains were 16 h,14 h,20,20 h;Comprehensive research results show that the optimal cellulase and ligninase temperature and p H of Bacillus subtilis are 37°C and 6.5,respectively;the optimal acid production temperature of lactic acid bacteria is 37°C.Experiment 2 Effect of solid-state fermentation with compound bacteria on nutritional quality of jujube feedIn the test,the nutritional content,sensory status,p H,aflatoxin B1,and zearalenone of fermented jujube powder products were used as evaluation indicators.Three progressive correlation tests were designed.Experiment one,using Saccharomyces cerevisiae(S2,S11),Lactobacillus plantarum(R7,R9),and Bacillus subtilis(B26,B37,C61)to form a composite bacterial agent as an experimental optimization factor,the single bacteria addition gradient was 2%,3%,4%,designed a three-factor,three-level orthogonal test to explore the best formula for compound bacteria;test two,the amount of different bacteria(according to the results of experiment 1),water content(20%,30%,40%)and the amount of bran added(20%,30%,40%).Orthogonal experiments of three factors and three levels were designed to optimize factors for the experiment.The optimal fermentation conditions were explored.In experiment three,fermentation time was the only variable as the experimental factor.Explore the optimal fermentation time.The results show:1)The addition ratio of different fungicides has different effects on the nutrient content of jujube feed.The content of flavonoids,polyphenols,reducing sugars,and NDF and ADF degradation rates of Mix4,Mix5,and Mix8 are significantly higher than those of other combinations and control groups(P<0.01);2)Optimization of fermentation conditions for jujube feed:The flavonoid polyphenol content Mix A was significantly higher than other combinations(P<0.01);the reducing sugar content Mix C was extremely significantly higher than the other combinations except Mix A and Mix D(P<0.01);The degradation rate of NDF and ADF Mix A was significantly higher than other combinations(P<0.05);3)The fermentation time had a significant effect on the nutrient content of jujube feed(P<0.01);the 5th d of flavonoid content fermentation was significantly higher than the4th and 6th d(P<0.01);the 5th d of polyphenol content fermentation was significantly higher than the 4d(P<0.05);the reducing sugar content of the fermented 7 d was significantly higher than other fermentation times(P<0.01).On the 6th day of fermentation,the p H of red date feed reached a minimum of 4.11.The contents of aflatoxin B1 and zearalenone in jujube feed under different fermentation time conditions were in line with China's feed sanitary production standards.Under the conditions of this test,the optimal fermentation conditions for jujube meal feed are:the best formula of the compound bacteria is Saccharomyces cerevisiae:Lactobacillus plantarum:Bacillus subtilis=2:1:2,the amount of compound bacteria is 3%,The amount of skin added was 20%,the moisture content of the fermentation substrate before inoculation was 20%,and the fermentation time was 6 days.Under these conditions,the flavonoid content was increased by 31.23%compared with the raw material group,and the polyphenol content was increased by 17.12%compared with the raw material group.