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Subject: Veterinary Public Health × End date: 2012 × Start date: 2012 × Thesis Type: M.V.Sc. ×
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    ThesisItemOpen Access
    IN VITRO EVALUATION OF DIFFERENT LACTIC ACID BACTERIAL STRAINS FOR THEIR PROBIOTIC CHARACTERISTICS
    (SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517 502. (A.P.) INDIA, 2012-11) SRINU, B; MADHAVA RAO, T(MAJOR); SHASHI KUMAR, M; KONDAL REDDY, K
    ABSTRACT : Identifying probiotic characteristics of bacterial strains by in vitro studies forms basis for selection of functional probiotics for commercial use. The objective of study was to collect different cultures and screen to study their functional probiotic characteristics such as acid tolerance, bile tolerance, antibacterial activity, antibiotic sensitivity, temperature tolerance and acidifying activity. Among the eighteen Lactic acid bacterial strains studied, 15 showed good survivability at high bile salt concentration (0.3 to 2 % oxgall) and good growth at a pH of 1.5 to 3.5. These probiotic species showed good survival abilities in acidic pH 2.0 to 3.5 except Lactobacillus delbruckii bulgaricus 281, Bifidobacterium bifidum 232 and Bifidobacterium bifidum 235, which did not grow at pH 2.0. Lactobacillus fermentum 141 and Pediococcus acidolactici 252 was able to grow even at pH 1.5 also. All the 18 lactic acid bacterial strains showed a count (CFU/ml) in the range of 0.23x107 to 2.7x107 at pH 2.0 except Lactobacillus delbruckii bulgaricus 281, Bifidobacterium bifidum 232 and Bifidobacterium bifidum 235, which did not form detectable CFU/ml, whereas Lactobacillus helviticus 194 showed highest count of 2.7x107 CFU/ml at pH 2.0. Among all the Lactobacillus spp. Lactobacillus paraplantarum 321 and Lactobacillus paracasei 22 showed maximum growth at 0.3% oxgall concentrations similarly Bifidobacterium bifidum 233 and Bifidobacterium bifidum 236 showed maximum growth when compared to other bifidobacterial strains. Among eighteen Lactic acid bacterial strains Lactobacillus casei 17, Pediococcus acidolactici 252 (except Clindamycin), Lactobacillus delbruckii bulgaricus 281 (except for Nitrofurantoin, Clindamycin and Cefpodoxime) and Lactobacillus helviticus 194 (except for Gentamycin, Nitrofurantoin and Streptomycin) were resistant to all the antibiotics tested. Bifidobacterium bifidum 231 (except for Streptomycin and Kanamycin) and Bifidobacterium bifidum 236 (except Norfloxicin) showed resistance to all antibiotics tested. All these Lactic acid bacterial strains were screened for in vitro inhibition of pathogenic microorganisms namely Proteus vulgaris, E.coli ATCC, E.coli 448, Pseudomonas aeruginosa, Klebsialla pneumoneae, Salmonella typhimurium, Bacillus cereus, Salmonella para-B, Staphylococci aureus. All the eighteen strains showed good antibacterial activity against the tested pathogenic bacteria. The strains of Lactobacillus paraplantarum 321, Pedicocci acidolactici 252 and Lactobacillus bulgaricus 281 inhibited the growth of all pathogenic bacteria. Bifidobacterium bifidum 232 and Bifidobacterium bifidum 233 (except Bacillus cereus and Salmonella typhimurium) also inhibited the growth of all pathogens tested. All the eighteen Lactic acid bacterial strains showed growth at all the tested temperatures (15oC, 40oC, and 45oC) except Bifidobacterium bifidum 229, Lactobacillus fermentum 141 and Lactobacillus rhamnosus 18 which have shown growth only at the temperatures of 15oC and 40oC, except at 45oC Among twelve Lactobacillus spp. Lactobacillus helviticus 194 has shown the highest acidifying activity, whereas Lactobacillus casei 17 shown lowest acidifying activity. Similarly Bifidobacterium bifidum 231 shown highest acidifying activity, whereas Bifidobacterium bifidum 236 shown lowest acidification values when compared with the other Bifidobacterial strains. The present study identified functional probiotics for future in vivo studies to commercialize probiotic strains of lactic acid bacteria to promote public health.