Strain Screening Of Sheep Compound Probiotics And Study On Freeze-drying Conditions

This study aimed to research the effects of nine different probiotics on ruminal fermentation by in vitro, screening out effect superior strains,9 strains of bacteria included Saccharomyces cerevisiae I.Saccharomyces cerevisiae Ⅱ,Candida tripicalis Ⅰ,Candida utilis, Candida krusei, Issatchenkia orientalis, Saccharomyces cerevisiaeⅡ,Candida tripicalis II, Bacillus subtilis respectively, numbered S1、Y10、 S13、S8、S14、S9、S3、Y7、C.Researching the effect of composite probiotics on ruminal fermentation by the method of composite probiotics followed, explorating the superiority of adding composite probiotics. At the same time through the study of lyoprotectant and optimization of freeze-drying process produced a higher vitality powder and reasearched the study of addition level of composite probiotics.The results of the test showed that:In the first experiment, With different forage-concentrate ratio, pH value of 9 strains trended to decrease and NH3-N concentration generally increased with no significance, a outstanding higher concentration of microbe protein(P<0.05)was found when the S3 was used compared to the control. Both of gas production and degradation rate of each group increased with the ratio of 3:7, the acetic:propionic (A:P) of Candida utilis was significant higher than the control (P<0.05). S1、Y10、S8、S14、S9、C groups degradation rate and gas production have increased with the ratio of 7:3, S9、S3、Y7、Cgroups acetic, propionic, butyric and TVFA have increased and S1、Y10、S13、S8、S14groups have decreased; the A:P of Y7 groups was significant higher than the control (P<0.05). S1、 S14、S9、C can be used as compound probiotics with the ratio of 3:7; S3、S9、C、Y7 can be used as compound probiotics with the ratio of 7:3.Research the effect of Composite probiotics on ruminal fermentation by in vitro refound that the same Composite probiotics with the ratio of 7:3 showed higher pH and A:P than the ratio of 3:7,degradation rate, gas production, microbe protein and TVFA have increased without significance. The pH of CL group was outstangding higher than the control with the ratio of 7:3 (P<0.05);the gas production, degradation rate and microbe protein of JL group was significant higher than other group (P<0.05);the degradation rate and NH3-N concentration of CL and HH groups were significantly higher than other groups (P<0.05). The concentrate of TVFA of HH group was highest. The pH,gas production and NH3-N concentration of each group were significant higher than the control (P<0.05). Concluding that HH group was the best combination through associative effects.In the second experiment, S1 was used as the experimental strains to select milk, glycerol and sucrose as protectant by designing Orthogonal experiment, fermentation broth was dryly treated by freeze-drying process, the optimum compounding of protectant is 15g/100ml milk,8g/100ml glycerol and 10g/100ml sucrose, survival ratio is 89.77%. By studying the addition ratio of protective agent, pre-freezing time and freezing-drying time obtaining the results that the survival ratio was highest when the addition ratio is 1:1, freezed in minus 20 degrees for one hour and in minus 80 degrees for two hours and freeze-drying 24 hour. Survival ratio reached 89.9% after tested.In the third experiment, Study the effects of different adding level of compound powder on ruminant in vitro with different concentrate-roughage ratio of substrate.The results discovered that adding mealy microbial can increase degradation rate, gas production and the concentration of NH3-N, and also make the pH be within normal limits. Best addition level was 0.08%.