| Summary: | 碩士 === 國立中興大學 === 畜產學系 === 89 === The aim of this study was to study on screening Lactobacillus strains from GI tract as probiotics. 11 strains of Lactobacillus are from rabbit, poultry and pig intestine and buying from CCRC. For in vitro strains characterization analysis, in the capability of tolerance to acid, the test strains from intestine were incubated in pH 2.0 sterile phosphate buffered saline for 3 hours at 37℃ compare with non incubated in that, the viable counts of these strains were decreased 2-3 log cfu/mL, but the count of CCRC 14016 strain only 102 cfu/mL. The result indicated the strains from intestine were capacity for surviving acidic conditions better than the CCRC 14016 strain. Strains from intestine were average capability of bile tolerance around 84%, but CCRC 14016 strain was only 7.4%. The ability to inhibit pathogenic, except for S13 strain, all of strains were inhibit Salmonella typhimurium I50 (Sal. typh. I50) and Escherichia coli (E. coli, CCRC 14675), and the most of strains can resist different antibiotic. For adhesive ability assay, it shows R08, R10, PG4, PG5, PG17, PL125, S13 and S18 strains can adhere to crop squamous cell. Strains of R10, PG4, PG 17, PL125, S13, S18 and CCRC 14016 can adhere to intestine epithelial cell of the broiler. In addition, the strains activate Raw 264.7 macrophage cell line, so the strains might have potential capacity to promote immunity of host. For the in vitro test choice PL125 strain be candidate of probiotics strain, and carry out animal experimental. 19 one-day old SPF (Specified-pathogen-free) broilers were divided into three groups, 7 broilers for negative control, 7 broilers for positive control and 5 broilers for treatment group. Positive control and treatment group received oral treatment of CCRC 14016 and PL125 strain (108/mL). The two media for Lactobacillus tested showed on content and wall of the broiler intestine in 3 and 7 day. The LAMVAB agar showed the lower counts than Rogosa agar. Lactobacillus counts were higher for the broiler intestine of treatment PL125 strain than the others in 3 and 7 day (P<0.05). In Rogosa agar, Lactobacillus counts of the broiler excreta in one day, PL125 treatment group was highest among three groups, but not significantly different among the three treatments group in the other days. In LAMVAB agar, the counts for PL125 treatment group were highest than the others groups (P<00.5). Using colony-PCR methods for detection of PL125 strain survive in the broiler intestine. This result showed that broilers oral treatment PL125 strain, then from the broiler intestine content or excrea can detect PL125 strain, so the strain can passage gastrointestinal tract environment. In addition, the SEM also showed PL125 strain survival in the broiler caecum. To summarize, it was proof that broilers oral treatment PL125 strain and the strain can survive in the broiler intestine, but the stain in the commercial rearing of broilers awaits further investigation.
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