Identification And Characterisation Of Lactic Acid Bacterial Isolates And Their Effects On Immune Synergism With Classical Swine Fever Vaccine

The identifications and characterisations were carried out for 9 of lactic acid bacteria isolates from intestine and excreta of the healthy piglets. The isolates of lactic acid bacteria were selected by the bile tolerance test in their ability to grow in gut microbiological environment and 2 of the isolates picked as candidates. After the culture media selection and frozen-dry storage method optimized, the frozen dried powder were use as feed additional supplements fed to the piglet, then the immune synergism effect will under monitored. The results shown:The 9 of isolates differentiated by morphological characterisation, property of staining and AP1500HL method test:1 Lactobacillus coprophilus ,1 Lactobacillus salivarius 1 Lactobacillus plantarum, 2 Lactobacillus acidophilus, 2 Lactobacillus fermenti, 1 Enterococcus faecalis,1 Lactococcus lactis ssp lactis1。The bile tolerance selection results showed that the one of each isolate was identified from lactic acid bacteria Lactobacillus plantarum and streptococcus Enterococcus faecalis , suitability to survived in gut environment. To compare for acid tolerance and bile tolerance ability of two isolate candidates, with Lactobacillus plantarum's acid tolerance ratio and bile tolerance ratio reached to 90.49% and 87.02%, respectively; and with Enterococcus faecalis, the acid tolerance rate was 86.73% and bile tolerance rate was 66.52%, lower than other.The medium selection was based on modification with de Man, Rogosa, and Sharp broth composition, addition of ingredients follow the bacterial nutrition requirements: (a) Nitrogen; (b) Carbon source; (c) Growth factors ( amino acid and vitamins etc.); and (d) Buffering solution. As the results showed that Lactobacillus plantarum suitable to growth in formulation based on MRS broth contained as 0.5% of peptone, 1% of lactose, and 0.5% of yeast extract; the comparable pH values were 6.4-6.8 range.The bacterial yield was reach 3.65×10¹²cfu/ml under the anaerobic condition at 39℃for 24 hours. Furthermore, the Enterococcus faecalis growth in MRS broth contained as fish peptone (0.5%) and yeast extract (0.5%); adjusted pH value was 6.4-6.8 range. The individual strains were grown overnight (anaerobic at 39℃for 24 hours) and harvested highest yield reached 5.61×10¹²cfu/ml.The bacterial viability rate improved during processing under frozen-dry condition by protectors. The result shown that best protector was formulated contain 10% of skim milk, 1.5% of sodium glutamate, 0.5% of L-cysteine, 2% of lactose and 10% of dextrin; their viability rate enhanced to 91.6% and 81.4% for Lactobacillus plantarum and Enterococcus faecalis, respectively.The vaccine-induced antibody titres against classical swine fever, as measured from piglets by provided the feed additives bacterial frozen–dry powders contained the Lactobacillus plantarum and the Enterococcus faecalis 10 days after fed. The result showed that antibody titres of the 0.5% of Lactobacillus plantarum and the 0.3% of Enterococcus faecalis treatment groups were had significant (p<0.01) different compare with control treatment, but other treatment groups did not significants. As a fed piglets after 30days, results showed that the antibody titres of all treatments group had significant (p< 0.01) different compare with control treatment, but the Lactobacillus plantarum group and the Enterococcus faecalis group did not significant (p>0.05).