Screening Of Lactic Acid Bacteria Producing Antimicrobial Peptides And Protein In Broiler Effect Of Dietary Supplementation

It was firstly reported that we screened out the high quanlity of Lactic acid bacteria, which can produce high quantity antibiotic peptide in our study. we identified the species of this Lactic acid bacteria and the production of antimicrobial peptides。Meanwhile, the working conditions of antimicrobial peptides and its application were studied. These data provide the foundation for application of antimicrobial peptides in animal husbandry The main results obtained as follows:1. secrrening out the strain of production antibiotic peptide and its identificationA strain L-209 producing antibiotic peptid was separated through plate method (primary screening), cylinder plate method and biomass (secondary screening). Aceording to its morphological and physiological characterizations, the selected strain was preliminary identified as Lactic acid bacteria. This antimicrobial peptide was identified as a molecular weight of between 5.856-7.823 KDa by means of organic acid effect excluding the impact of its protease inhibition, and ammonium sulfate precipitation, dialyzing, vacuum freeze-drying concentrated and Tricine-SDS-PAGE electrophoresis.2. Optimization of work conditions for antibiotic peptide produced by Lactic acid bacteria L-209Taking the biomass and production of antibiotic peptide as main principle, the optimum conditions for antibiotic peptide of bacillus sp. L-209 were confirmed by single-factor experiments and uniform design experiments. The optimum conditions were as follows:carbon composite 35.0 g/L、complex nitrogen source 17.5 g/L, K2HPO4·3H2O 2.0 g/L, ZnSO4·7H2O 1.2 g/L, inoculation size 0.5%, otating speed 150 r/min, culture temperature 32℃, original pH 6.0 and culture time was 15 h. The antimicrobial peptide inhibition zone circle diameter could reach up to 34mm by cylinder plate method in the optimum conditions.3. Effects of antimicrobial peptides on broiler dietsAntibacterial peptide was added to the feed of broilers, which could improve the development of immune organ, and increased the level of serum H5N1 AI Antibody and ND Antibody and complement C3、C4、immunoglobulin IgG、IgM、lysozyme and serum protein contentin broilers’serum. These results indicated that antibacterial peptide could boost immunity of poultries, which could significantly improve the 21,42-day-old broiler live weight, and good quantity increasing, feed conversion ratio reduction (p<0.05).All results suggested that antibacterial peptide could improve broiler performance and the effect was better than antibiotics.