The Identify Of Superior Strains As Animal Microbiological Agent And Study On Fermentation Conditions

The vallum of export is livestock epidemic disease and antibiotic residue in our country. It is the key for our livestock product to get into international market.Our stockbreeding is a large percentage as a whole agriculture. Therefore, developing new feedstuff or feedstuff additive,especially biology preparation,is the important approach to produce safe, pollution-free and nonrudimentation livestock product.This thesis analyzed on the configuration ,zoology,physiological and biochemical characters of isolation strains and identify by molecular biology methed,discussed the strains′function mechanism based on some relative character,studied on the liquid ,solid and mixed fermention technics,ensured the effect of microeologial ageent by animal feeding experiment.The results indicated:1. The B02 and B03 strain was identified as Bacillus cereus, based on the results of morphological,physiological characteristics and the homological analysis of 16S rDNA sequence. The phylogenetic tree built on the 16S rDNA sequence indicated B02 and B03 strain was the nearest to one of Bacillus cereus. The animal toxicity text identified that two strains of Bacillus were safe for producting medicament or submedicament when under nomal dosage. Obtained two superior strain,which were isolate from soil: Aspergillus fumigatus F10 and Aspergillus oryzae F20,and confirmed the classified status and security.2. The function mechanism of B02 and B03 had been preliminarily established which was biologic robbing oxygen primarily, keeping the balance of strains secondarily,many availability metabolize production can increase the digest and absorptivity of animals.3. Optimized the liquid and solid fermentation technics of B02 strain. The best liquid fermention conditions are :bean pulp 0.2 g·kg^-1,KCL0.02 g·kg^-1,initail pH5.0,temperature 35℃;the best solid fermention condition are : crop stalks and bran 7/10, fat residue 3/10,initail pH7.5,water content 85 %,inoculum size 10⁶·ml^-1, temperature 33³5℃。It provided nice theory and technic support to production and application of the microeologicai ageent.4. Studied on the conditions of spore form,the results shows: it is can be remarkably improve growth speed ,growth quantity and advance spore form by appending proper Ca²⁺or Mg²⁺. 5. Optimized the solid fermentation technics of two aspergillus F10 and F20, ascertained the mixed fermentation technics of Bacillus cereus B02 and Aspergillus fumigatus F10.The best mixed fermentation conditions are: initail pH7,inoculum size 105·ml^-1,cultivated 60 h under 35℃.On this condition, the strain number of B02 can reach 1.792×10¹³ cfu·mL^-1;the enzyme activity of solid substrate can reach 6 028.5μg·(g·min)^-1。It provided superior strains and technic support to produce animal enzyme preparation and microeologicai ageent.6. The animal feeding test indicated: compound microbiological agent were taked according to 5.0×10⁷·kg^-1can prevent Salmonella choleeraesuis enteritis, the cure rate can reach 90% when taked according to 2.0×10⁸·kg^-1. It is therapeutic equivalence with terramycin.It could prevent white diarrhea of chicks,protect chickling from infecting of Salmonella Pullorum, reduced death rate, increased suvive rate. The cure rate can reach 90% when taked according to 2.0×10⁸·kg^-1, It is therapeutic equivalence with ciprofloxacin.