Screening High Tolerance Bacillus For Poultry And Study Its Prebiotic Effect Of Laying Hens

Many countries had forbidden the use of antibiotics as feed additive for drug residue and drug resistance. Animal micro-ecological preparation emerges as a promising agent to replace antibiotics feed additive for such advantages as not exerting toxic and side effects, safety and reliability, multi-function, no residue, and being environmental friendly. However, some problems still existed in it, for example, most bacterial strains showed the drawbacks of planting difficulty, insufficient tolerance, and weak competitiveness. As a result, it had always been the study focus to search for probiotics with good effect, high tolerance and high drug sensitivity. To find the ideal probiotic probiotics production, we screened high tolerance Chicken bacillus and its role in prebiotic research.In this study, six strains of bacillus were isolated from the gastrointestinal tract of chicken as D1、S1、W1、W2、R1and R2. Physiological and biochemical identification and16SrDNA molecular identification of the strains were performed respectively. The results showed that D1、W1and R2were bacillus subtilis; S1、W2and R1were bacillus vallismortis DSM11031. Biological characteristics study of bacillus subtilis DSM10and bacillus vallismortis DSM11031showed that the logarithmic growth phase of the two strains were2～12h, with optimum growth temperature ranging from37℃～42℃, optimum pH6～7. The drug sensitivity experiment demonstrated that bacillus subtilis DSM10and bacillus vallismortis DSM11031were highly sensitive to such drugs as Amoxicillin, Compound sulfamethoxazole, Tetracycline, Kanamycin, Gentamicin, Cephalexin v, Streptomycin sulfate and Ciprofloxacin, and they are proved to be appropriate micro-ecological preparations.High enzyme production screen and high tolerance screen were performed respectively for bacillus subtilis DSM10and bacillus vallismortis DSM11031, and two bacteria strains were obtained with high productivity of amylase protease and high tolerance to artificial gastric juice, artificial intestinal juice and bile salt from pig. Animal experiments of the two strains showed many effects of them in various degrees, including promoting chicken growth, increasing feed conversion ratio, enhancing body immune organ growth, increased the number of probiotics in gastrointestinal tract such as bifidobacterium and lactobacillus, reduced the number of harmful bacteria such as escherichia coli and salmonella. Moreover, bacillus subtilis showed better living benefitting effect than that of bacillus vallismortis. The comparison of the live benefiting effects of the two strains with their adherence rates to intestinal mucous glycoprotein showed that Bacillus subtilis Bacillus was140.97%higher than Bacillus vallismortis, The results showed that the living benefiting effect of bacillus for animals may be correlated with the adherence to intestinal mucous glycoprotein to some degree. This study focused on the living benefiting effect and mechanism of the two strains of bacillus for animals, and provided basis for the further study of micro-ecological feed additive.