Study On The Solid Fermentation Technique Of Astragalus Using Lactic Acid Bacteria And Its Application On Weaned Piglets

Mixed Entercoccus faecium and Lactobacillua plantarum were used to ferment with Astragalus in the form of solid fermentation. Firstly, the feasibility of fermenting Astragalus using the two species of lactic acid bacteria was determined, as well as the optimum adding amount and the best fermentation condition. Secondly, the content of Astragalus polysaccharide(APS) and Astragaloside IV in fermentation production was examined over the effect of fermented Astragalus components. Lastly, to study the effect on growth and immune response and the possibility as a health care medicine, instead of antibiotics, in weaned piglets, different doses of fermentation production were added in the feed of weaned piglets, compared with antibiotic group. The eaperiment covers the following three sections:(1)The optimization of solid fermentation technique of lactic acid bacteria and Astragalus. Tests were divided into four groups to cultivate the two species of lactic acid bacteria according different adding amount of Astragalus(25%, 50%, 75%, 100%). The viable count of lactic acid bacteria was taken as an index to determine the optimum adding amount of Astragalus. To avoid the interference of uneven nutrition, the first three groups were added 25% nutritive substrate(nutritive substrate was made up of equal amounts of wheat bran, corn flour and papaya slag). The groups which component proportion less than 100% were filled with solid inert carrier. The results showed that the viable count of lactic acid bacteria rose first and then fell with the increase of Astragalus amount after fermenting 3 days. The bacterial amount of the group which added 50% of Astragalus were the largest. So the optimum adding amount of Astragalus was 50%. The content of Astragalus polysaccharide was taken as a index to optimize the fermentation conditions(fermentation time, inoculums size and water content). The optimization result was as follows: fermentation time was 12 d, inoculums size was 25%, water content was 50%.(2) Effect of the solid fermentation on the active components of Astragalus. The results showed that APS was increased by different degrees after fermentation. APS content ascended to the highest value on the 12 th day in the fermentation group. HPLC-ELSD was used to determine the content of Astragaloside IV in Astragalus. Astragaloside IV content ascended to the highest value on the 18 th day in the fermentation group, but there was a minor change compared with the control group. In the late fermentation stage, Astragaloside IV content in the fermentation group was slightly lower than that in control group. Presumably it was converted into other substances.(3)The application of fermentation preparation of Astragali in weaned piglets. One hundred and sixty 35(±3) days’ weaned piglets(Duroc× Landrace× Large White) were randomly divided into 5 groups. Experimental groups were 0.2% fermentation preparation group, 0.4% fermentation preparation group, 0.6% fermentation preparation group and 0.8% fermentation preparation group. Antibiotic group added colistin sulfate. Trial period was 28 days. The results indicated that, compared with the antibiotic group, 0.4% fermentation preparation group, 0.6% fermentation preparation group and 0.8% fermentation preparation group improved the growth performance and the content of Ig G and Ig A. Taken together, 0.6% fermentation preparation group proved the most obvious effect. Compared with the antibiotic group, 0.6% fermentation preparation group made feed intake increase by 12.2%(P<0.05), daily gain increase by 19.8%(P<0.05), feed conversion rate reduce by 6.2%(P<0.05), Ig G increase by 30.2%(P<0.05) and Ig A increase by 22.1%(P<0.05). These results suggested that adding appropriate fermented Astragalus can subrogate antibiotic for the medical care of weaned piglets.