Study On Extraction Of Effective Ingredients From Leave Ginkgo, Bacteria Inhibitory Effect In Vitro And Application In Meat Chicken Diets

Paper was conducted to study feasibility of substituting antibiotics for gingkgoleaves in meat chicken dietary. Two experiments was finished, where one was designedfor extracting effective ingredients and studying bacteria-inhibitory effect in vitro, and theother for studying substituting effect of gingkgo.Experiment 1: Here, 75% ethanol solvent and ultrasonic technology was applied.Mono-element trials, were designed to determine proper usage of three elementsincluding solid-liquid ratio, temperature and time. Orthogonal method L9(3⁴) was used todetermine optimal extracting technical parameters. Results suggested as follows:solid-ratio of 1:15, 65℃as extracting temperature and 1 hour of extracting, accounted forthe best extracting condition; bacteria inhibitory trials showed the lowest bacteriadepressing concentrations on S.aureus, E.coli and P.multocida were 0.025 g/mL,0.025g/mL,0.050 g/mL, respectively, while drug-resistant to Candida albicans; Disk diffusionmethod indicated gingko leaves extracts had better bacteria-inhibitory effect on Candidaalbicans than gram-positive strain antibiotics such as penicillin and erythromycin, andalso better than gram-negative strain antibiotics such as gentamicin and enrofloxacin onE.coli and P.multocida.Experiment 2:240 1-day-old AA meat-chicken were randomly allocated into 6groups(1 control group and 5 experimental groups). Each group comprised 2 replicatesand each replicate group included 20 chickens. Trial time was 35 days. Lincomycin(22mg/kg)was added in control group and five levels(1 g/kg,2 g/kg,3 g/kg,4 g/kg,5 g/kg)of gingkgo leaves dried powder(containing flavonoids of 0.06 g/kg,0.12 g/kg,0.18 g/kg,0.24 g/kg,0.30 g/kg, respectively) were added in experimental groups. Experiment wasdesigned to study effect of gingkgo leaves substituting antibiotics on chicken growth, serabiochemical indexes and immunological function.Resulsts suggested as following: (1)1g/kg～5 g/kg addition contributed positively to growth of certain degrees, among which 3g/kg addition was positive significantly (p＜0.05); (2)addition of power in dietary had nosignificant effect on survival ratio (p＞0.05); (3) 1 g/kg～2 g/kg addition raised sera grossalbumen and globin significantly (p＜0.05); 5 g/kg addition increased bursa of Fabriciusindex (p＞0.05) and thymus index (p＜0.05) ; sera GOT activity improved as concentrationof gingkgo leaves raised, while not significantly (p＞0.05); 5 g/kg addition increased seraGPT activity (p＜0.05) and decreased sera urea concentration of nitrogen, cholesterol andglycerol, respectively (p＜0.05); (4) 1 g/kg～3 g/kg addition raised level of AIH₅ antibodyin sera. The following conclusion can be drawn from all the above results:Gingko powdercould serve as a novel plant feed additive which could improve chicken growthperformance, promote immunity, drop sera lipid content and substitute feed antibiotics ofsome degree, therefore, gingko power would present a brilliant prospect.