Abstract

Backgrounds/Objectives: Probiotics confer health-promoting and immunomodulatory effects on the host. However, a lot remains to be understood regarding their safety profile, characteristics and functional mechanisms. This study was conducted to comprehend the functional mechanisms of Limosilactobacillus reuteri isolated from chickens and characterize some of its uncharacterized proteins (hypothetical proteins). Methods: The chicken-isolated Limosilactobacillus reuteri genome, sequenced using Illumina MiSeq sequencing technology, was explored for proteome comparison analyses, comprehensive antibiotic resistance analysis, interleukin-4 (IL-4) expression across various conditions as well as IL-4-inducing potential. Results: Five antibiotic resistance-associated genes were found. Hypothetical proteins labeled QHPv.2.1, QHPv.2.12 and QHPv.2.16 induced IL-4, but QHPv.2.12 was not immunogenic. Immunogenic IL-4-inducing mutants from QHPv.2.1 (0.7013) and QHPv.2.16 (0.7040) had the best support vector machine (SVM) values, which were significantly (p < 0.05) higher than the rest of the group, followed by those from QHPv.2.12 (0.4587). QHPv.2.5 (0.0560) had the lowest value. QHPv.2.1 (5484.71) and QHPv.2.16 (5491.05) had significantly (p < 0.05) larger molecular weights (MWs), followed by QHPv.2.12 (5302.05). The lowest value was obtained for QHPv.2.7 (3386.74). Conclusions: This explorative study revealed the IL-4 inducing capacity of the hypothetical proteins of L. reuteri and their mutants, as well as identified heat and cold shock proteins associated with L. reuteri.

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