Identification And Preliminary Application Of Lactobacillus From The Feces Of Piglets

To further clarify the antibacterial mechanism of Lactobacillus and find a way to keep its activity in the production practice, the study was carried out by isolating and screening excellent strains from fresh feces of healthy piglets within 10 days of age from ya’an. one of strain of lactobacillus which had good antibacterial effect and strong acid was selected to develop a high activity Lactobacillus preparation to preventing and promoting the growth of piglets.Isolated strains were identified by routine bacteriology and 16SrRNA.The identification of 13 strains of Lactobacillus showed that they were Lactobacillus salivarius, Lactobacillus salivarius subsp salicin and Lactobacillus acidophilus.Through the survival experiment under the condition of tart surroundings pH2.0, YW-7,YW-1 and H109 strain were screened out form diverse concentration of bile salt and high proteas for the subsequent research, which could survival in the tart surroundings pH2.0,0.3% bile salt and 1.4% digestive enzyme.To demonstrate the inhibition of E.coli generated by isolated Lactobacillus strains, culture medium was developed to promote the Lactobacillus grow together with E.coli. Mixed culture in vitro antibacterial test confirmed that the antibacterial activity of Lactobacillus related to the species, the concentration of live bacteria and the value of pH. YW-7 had a fastest pH decrease rate in culture liquid, and the lowest pH value reached 3.29, and also had a strongest antibacterial capacity. When the proportion of initial Lactobacillus and E.coli was 1:1,2:1 and 4:1, respectively at 12 h,8 h and 24 h presented completely bacteriostasis and YW-1 strains times,H109 lines is the worst.In the antibacterial test of Oxford cup method, YW-7 showed the strongest inhibitory effect on E.coli. The diameter of inhibition zone was 13.08～20.14 mm.The inhibition effect of YW-1 and H109 were weaker of which the zone were 11.24～17.32 mm,12.32～18.24 mm, in diameter respectively. The same pH value of HCl bacteriostatic circle were 0, had no effects on E.coli.When the pH value was adjusted to 3.00, E. coli inhibition zone diameter of only 9.56 mm, far below the inhibitory effect of fermentation supernatant. It showed that the acid can help the Lactobacillus to exert the antibacterial effect, but not the only factor.The results of GC-MS showed that the strains can produce lactic acid, phenyllactic acid, stearic acid, proline, alanine,acetic acid, leucine glycine, palmitic acid and vitamin C. Ability to sort for producing acid was the YW-7> YW-1>H109. The longer the incubation time of lactic acid bacteria, the higher the content of lactic acid and phenyllactic in the culture broth. YW-7 cultivated to 24 h can be up to 14.52 mg/mL and 1.47 mg/mL.YW-7 production of lactobacillus for the treatment and prevention of bacterial diarrhea in piglets, and its effect is equivalent to antibiotics, which can recover only 2 to 3 days, but the product Ⅰ group and the product Ⅱ group were invalid. Diarrhea rate of YW-7, product Ⅰ, product Ⅱ and the antibiotic group were 7.15%,7.95%,12.2% and 7% respectively. After 10 days, the number of lactic acid bacteria and E.coli in YW-7 group was significantly higher than that in the product Ⅰ group, the product Ⅱ group and the antibiotic group(P<0.01). Piglets weight gain was 103.57%, significantly higher than the other three groups(P<0.01). It is proved that YW-7 can effectively treat bacterial diarrhea in piglets, improve the intestinal environment and promote the growth of piglets.There were no diarrhea happened when YW-7 lactobacillus was used at weaned piglets 15 days continue, and the product Ⅰ group, the product Ⅱ group and blank group were 3%,7% and 8.3%;The weight gain rate of YW-7 group was significantly higher than that of the other 3 groups(P<0.01).The ratio of feed to meat was only 1.28, which was significantly lower than the 1.49,2.34 and the 2.14 in the product Ⅰ group, the product Ⅱ group and blank group(P<0.05).Pigs average weight in YW-7 group was 5 kg higher than the other when fed to 100 days. The results showed that the preparation of YW-7 can significantly prevent the diarrhea caused by weaning stress, promoting the growth of piglets and reducing the consumption.