Probiotic biomarkers and models upside down: From humans to animals.

Probiotics development for animal farming implies thorough testing of a vast variety of properties, including adhesion, toxicity, host cells signaling modulation, and immune effects. Being diverse, these properties are often tested individually and using separate biological models, with great emphasis on the host organism. Although being precise, this approach is cost-ineffective, limits the probiotics screening throughput and lacks informativeness due to the 'one model - one test - one property' principle. There is а solution coming from human-derived cells and in vitro systems, an extraordinary example of human models serving animal research. In the present review, we focus on the current outlooks of employing human-derived in vitro biological models in probiotics development for animal applications, examples of such studies and the analysis of concordance between these models and host-derived in vivo data. In our opinion, human-cells derived screening systems allow to test several probiotic properties at once with reasonable precision, great informativeness and less expenses and labor effort.