Analiza in vitro preživljavanja odabranih probiotičkih sojeva u simuliranim uvjetima gastrointestinalnog trakta dojenčeta

master's thesis

• Title (english): In vitro survival analysis of selected probiotic strains in simulated conditions of the infant gastrointestinal tract
• Author: Maja Zovko
• Mentor: Jasna Novak (mentor)
• Committee member: Blaženka Kos (predsjednik povjerenstva)
• Committee member: Ksenija Markov (član povjerenstva)
• Committee member: Jasna Mrvčić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Biochemical Engineering); (Laboratory for Antibiotic, Enzyme, Probiotic and Starter Cultures Technology); Zagreb
• Defense date and country: 2024-12-19, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Nutrition

Abstract

Preživljavanje nepovoljnih uvjeta gastrointestinalnog trakta (GIT) jedan je od ključnih kriterija pri odabiru probiotičkih sojeva, jer je GIT ciljno mjesto njihovog djelovanja. Stoga je cilj ovog rada bio odrediti in vitro preživljavanje sojeva Levilactobacillus brevis brevis i Limosilactobacillus fermentum, prethodno izoliranih iz mikrobiote majčinog mlijeka, te procijeniti zaštitni učinak dojenačke formule prilikom tranzita analiziranih sojeva u simuliranim uvjetima gastrointestinalnog trakta. Preliminarno je određena tolerancija analiziranih sojeva na koncentracije žučnih soli, što je pokazatelj procjene potencijala probiotičkih bakterija da prežive in vivo.u intestinalnom sustavu. Oba soja pokazuju relativno visoku otpornost na žučne soli. Prema rezultatima analizirani sojevi preživljavaju u značajno većem broju probiotičkih stanica od propisanih 10x10⁶ CFU/m. Usporedna analiza preživljavanja sojeva potvrdila je učinkovito adaptiranje na simulirane uvjete želučanog sok i soka tankog crijeva , pri čemu Levilactobacillus brevis u usporedbi s Limosilactobacillus fermentum pokazuje pojačanu učinkovitosti. Pretpostavlja se pojačana otpornost analiziranih sojeva uslijed zaštitnog učinaka dojenačke formule u simuliranim uvjetima gastrointestinalnog trakta.

Abstract (english)

Survival of adverse conditions of the gastrointestinal tract (GIT) is one of the key criteria when selecting probiotic strains, because the GIT is the target site of their action. Therefore, the aim of this study was to determine the in vitro survival of Levilactobacillus brevis and Limosilactobacillus fermentum strains, previously isolated from the microbiota of human milk, and to assess the protective effect of infant formula during the transit of the analyzed strains in simulated gastrointestinal tract conditions. The tolerance of the analyzed strains to bile salts was preliminarily determined, which is an indicator of the assessment of the potential of probiotic bacteria to survive in vivo in the intestinal system. Both strains show relatively high resistance to bile salts. According to the results, the analyzed strains survive in a significantly higher number of probiotic cells than the prescribed 10x10⁶ CFU/m. A comparative analysis of the survival of the strains confirmed the effective adaptation to simulated conditions of gastric juice and small intestinal juice, with Levilactobacillus brevis showing increased efficiency compared to Limosilactobacillus fermentum. It is assumed that the increased resistance of the analyzed strains is due to the protective effect of infant formula in simulated gastrointestinal tract conditions.

• Keywords: probiotik; Lactobacillus; simulirani uvjeti gastrointestinalnog trakta
• Keywords (english): probiotics; Lactobacillus; simulated gastrointestinal tract conditions
• Language: croatian
• URN:NBN: urn:nbn:hr:159:710513
• Study programme: Title: Nutrition; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra nutricionizma (magistar/magistra nutricionizma)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2025-01-28 12:41:41