Fig. 3

Efficacy of dietary probiotics, prebiotics, synbiotics and postbiotics to restore the gut-liver axis function, metabolic health and performance in broilers and pigs exposed to heat stress. Convincing evidence exists that feeding of probiotics (mainly Lactobacillus (L.) ssp. and Bifidobacterium (B.) ssp.), prebiotics (cello-, fructo-, galacto- and mannan-oligosaccharides) and synbiotics (different probiotic mixtures with either cello- or galacto-oligosaccharides) is an efficacious strategy to protect broilers from heat stress-induced gut dysbiosis, impairment of gut barrier integrity and gut morphology and function, hepatic inflammation, hypothalamic inflammation, impairment of metabolic health and reduction of performance. In addition, results from a few studies show that dietary postbiotics based on inactivated L. plantarum strains alleviate the adverse impact of heat stress in broilers. In pigs, only a few studies demonstrated that feeding of probiotics (probiotic mixtures or a specific Saccharomyces cerevisiae strain) is also a suitable approach to protect from heat stress-induced impairment of gut integrity and function, metabolic health and performance. However, no studies are available in pigs investigating the efficacy of prebiotics, synbiotics and postbiotics on gut health, metabolic health and productivity under heat stress