Probiotic Strategies in Modern Pig Production: From Gut Microbiota Modulation to Immune and Metabolic Benefits*

Probiotics play an increasingly important role in supporting the health and productivity of swine, in response to the global demand to reduce antibiotic use and enhance the sustainability of pig production systems. The beneficial effects of probiotics are primarily exerted through modulation of the gut microbiota composition and activity, stimulation of immune responses, and improvement of metabolic and performance parameters. Probiotic efficacy strongly depends on the microbial species and strains used (e.g., Lactobacillus spp., Bacillus spp., Enterococcus spp.), the administered dose, delivery method, and the physiological stage of the animal. Numerous studies have highlighted the particular value of probiotics during the critical post-weaning period in pigs, where these supplements help reduce diarrhoea incidence and improve growth performance, as well as in sows, where probiotics enhance lactation outcomes, immune status, and offspring vitality. Probiotics are most commonly administered as feed additives, water supplements, or protective formulations, often in combination with prebiotics, enzymes, or organic acids to enhance their overall efficacy. There is an increasing interest in next-generation probiotics, including host-specific strains and preparations containing microbial metabolites (postbiotics). Despite the considerable progress, many aspects of probiotic action, especially their interactions with the intestinal environment and underlying molecular mechanisms, remain under intensive investigation. The dynamic development of this field suggests that probiotics represent a valuable tool for advancing modern, responsible pig production. The implementation of probiotic preparations in pig production represents an important step towards more ethical and sustainable production, in which animal health and welfare remain key elements of responsible herd management.