Here is a **concise, journal-style introduction (a few sentences)**:
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Commensal gut microbiota play a fundamental role in the development and regulation of host immunity in mammals. Disruption of the microbiota–immune balance leads to dysbiosis, which is closely associated with increased disease susceptibility. In contrast, the establishment of a stable and defined microbial community supports the maturation of immune functions. Among these, lactic acid bacteria have attracted significant attention due to their strain-specific ability to modulate immune responses and enhance host defense mechanisms.
Pigs are the only animal susceptible to human rotavirus (HRV)-induced diarrhea, making them an important model for studying host-microbe interactions. Studies in gnotobiotic pigs show that probiotic colonization with Lactobacillus rhamnosus GG and Bifidobacterium animalis Bb12 enhances HRV-specific IgA responses and reduces diarrhea severity. Similarly, colonization with the simplified Bristol microbiota upregulates serum IgA and IgM levels, supporting intestinal and systemic immune development in newborn pigs. These findings highlight the potential of gut microbiota interventions to modulate immunity and improve pig health.
Antibiotics are widely used in pig production to prevent disease and promote growth. However, their use can disrupt the gut microbiota, reduce beneficial bacteria, and increase opportunistic pathogens. These changes may affect intestinal health, immune function, and the spread of antibiotic resistance genes.
Many earlier studies have found that Lactobacillus is one of the main types of bacteria in pig guts. No matter the pig's age, these bacteria make up about 15% of the gut samples when looking at their 16S rRNA gene sequences. Lactobacillus lives in both the upper and lower parts of the pig's digestive tract and starts to settle there soon after birth.
Probiotics, as beneficial microorganisms, can enhance the health and production performance of weaned piglets through competitive exclusion of pathogens, reinforcement of intestinal barrier function, and modulation of immune responses. Their effects are strain-specific, with certain strains of Lactobacillus, Enterococcus, and other genera significantly improving feed conversion efficiency and inhibiting pathogenic bacteria such as E. coli. Meanwhile, prebiotics selectively promote the proliferation of beneficial bacteria and act synergistically with probiotics to further optimize gut microbial balance. This review systematically examines the mechanisms and applications of probiotics and prebiotics in regulating the intestinal microbiota of domestic pigs, providing a theoretical foundation for the development of functional feed additives in animal husbandry.
Breast milk provides essential nutrients for the development of newborn mammals, and peptide growth factors such as epidermal growth factor (EGF) and insulin-like growth factor-Ⅰ (IGF-Ⅰ) play a critical role in the intestinal growth and development, cell proliferation, growth, differentiation, and immune function of newborn animals. Therefore, breast milk is vital for the survival and development of newborn mammals.
