The Identify Of Superior Strains As Nimal Microbiological Agent And Tudy On Fermentation Conditions

Animal husbandry in China's agricultural production occupies a large proportion. It's akey factor in promoting rural economic growth, and increase farmers' income. But drugresidues in animal diseases and animal products seriously impact the quality of livestockproducts, and even threat to human health.To develop new types of probiotics, is a green,health, ecology, safety of livestock procucts effective way. In this study, tested bacillus'smorphological characteristics, biochemeical characteristics and molecular biologicalidentification of physiological have been studied. The liquid medium of the screening strainand solid state fermentation were optimized. The effect of feed Bacillus were determined bysafety test and animal test of the strains.The main conclusions are as follows:(1) The two bacteria, B02and B06, were filtered out from the eight tested strains by16SrDNA sequence analysis. Determining the B02strain was Bacillus cereus, B06was Bacillussubtilis by morphological chatacteristics and physiological and biochemical chatacteristicsanalysis results. Their taxomomic status were determined by phulogenetic tree.(2) Through the L9(34) orthogonal experiment showed that the optimal liquidfermentation medium of strain B02was divided into: corn flour30g·L^-1, soybean meal20g·L^-1, sucrose5g·L^-1, ammonium sulfate2g·L^-1.Through the environmental conditions of thesingle factor experiment, B02strain, the best culture conditions for the optimized medium asfollows: temperature35℃, the initial pH7⁸, vaccination age18h, the inoculum size105⁵×105/ml. Under this condition, the B02strain liquid fermentation, the number of bactera in thefermentation broth was up to (9.04±0.39)×1014cfu·ml^-1.B06strains the best media components: corn flour30g·L^-1, soybean meal20g·L^-1,glucose5g·L^-1, ammonium sulfate2g·L^-1.The optimal culure conditions were: temperation30³5℃, the fermentation brothinitial pH6.0, vaccination age16h, the inoculum5×105/ml,Under this condition, the B06strain liquid fermentation, fermentation liquid bacteria numberwas up to (1.74±0.13)×1013cfu·ml^-1.(3) In the liquid fermentation medium, adding a amount of Ca2+can increase the growthrate of the two bactera, growth and spore production rate. Adding Mg2+can enhance thegrowth rate and Bacillus rate of B02strain. Add of Mn2+can promote the growth of B06 strain and improve spore production rate.(4) Through the orthogonal experiment L9(34) B02strain the optimal solid-statefermentation medium components was as follow: wheat bran696.6g·kg^-1, soybean meal87.0g·kg^-1, corn flour87.0g·kg^-1, rice bran130.4g·kg^-1. Single factor test of the environmentalconditions showed that B02strain in the optimized medium, the optimal cindition for:temperation35⁴0℃, medium moisture content45%, initial pH7.5, inoculum105/g. In thiscondition, B02strain solid-state germentation, the number of bacteria in the fermentationsubstrate was uo to (2.34±0.058)×1014cfu·g^-1.B06strain the best media group was divided into: wheat bran761.9g·kg^-1, soybean meal95.2g·kg^-1, corn flour95.2g·kg^-1, rice bran47.7g·kg^-1. The optimal culture conditions:culture temperature30³5℃, medium water content60%, medium initial pH7.5, inoculum5×104/g. Under these conditons, cultured B06strains, bacterial counts of up to(1.72±0.035)×1011cfu·g^-1.(5) Safety Test results showed that B02strain was seak toxicity, and B06as avirulentstrains. Two bacteria as feed additives, feeding animals th amount of≤109·g^-1body weight issafe and nontoxic.(6) Animal feeding experimental results showed that: chicks diets by1.0×107·kg^-1feedamount add probiotics, can effectively prevent Salmonella pullorum, effectively reducing thechickens incidence of mortality. When the dosage of5.0×108·kg^-1, can treat chicks caused bySalmonella pollorum,90%cure rate with diprofloxacin efficacy considerable equal. Dietarysupplementation of probiotics can also significantly improve the growth performance ofchicks. Probiotics prevention group and probiotics treatment group all could significantlyraise the chicks daily gain(P<0.05), compared with the control group average daily gain wereincreased by24.53%and16.24%.