Characteristics of local immunity and intestinal microbiota in infants in different types of feeding

Objective. To conduct a comparative assessment of local immunity in the presence of functional gastrointestinal disorders (FGD) in infants depending on the type of feeding. Patients and methods. This prospective cohort study included 172 infants aged 0–6 months. All patients were divided into 3 groups: group I (n = 56) – formula-fed infants who received an adapted milk formula enriched with Bifidobacterium BB-12, Lactobacillus LGG and galacto-oligosaccharides; group II (n = 59) – formula-fed infants who received a standard adapted milk formula; group III (n = 57) – breastfed infants. To assess local immunity, the content of sIgA in coprofiltrates was determined by enzyme-linked immunosorbent assay. Microbiota composition was examined by a real-time polymerase chain reaction. A comparative assessment of individual tolerability of formulas, effects on the frequency of FGD, dynamics of changes in the coprogram, sIgA levels, and quantitative indicators of intestinal microbiota was performed. Results. In the group of infants fed with symbiotic complex formula, the incidence of infantile colic decreased by 57.1% (p = 0.0002). Stool microscopy also confirmed good digestibility of the functional milk formula, which was reflected in the reduction of pathological impurities (mucus and leukocytes) to 7.1% (p < 0.005), reduction of neutral fat and fatty acids: 56.6% and 28.5%, respectively (p > 0.05), reduction of iodophilic flora (21.4%, p > 0.05), which led to a significant decrease in the frequency of FGD (p < 0.005). Also, infants in group 1 tended to have higher values of sIgA (170.23 ± 9.56 mg/L) than infants in group 2 (152.73 ± 9.30 mg/L) after the use of formula with functional components (p > 0.05). When assessing the microecological status of intestinal biocenosis in group 1, in contrast to group 2, after using the functional adapted milk formula, the intestinal biocenosis approached the quantitative content of intestinal microorganisms in exclusively breastfed infants. In group 1, Lactobacillus spp. increased significantly to Me [Q1; Q3] = 3.30 [1.30; 4.10] (p = 0.0247), and Atopobium bacterium (vaginal opportunistic flora) was not detected Me [Q1; Q3] = 0.00 [0.00; 3.25] (p = 0.0000). Conclusion. An adapted milk formula with functional components can be successfully used in formula and mixed feeding in infants with increased risk of intestinal microbiota disorders and in the presence of FGD. Key words: children, intestinal microbiota, secretory immunoglobulin A, breastfeeding, formula feeding, functional gastrointestinal disorders