Abstract
Background:
Lesions of the pars esophagea in pigs are a common multifactorial, predominantly non-infectious gastrointestinal disorder associated with physicochemical, nutritional, and man-agement-related factors. Disruption of the physiological pH gradient between glandular and non-glandular gastric regions is considered a key mechanism in lesion development, while Lactobacillus spp. represent a stable component of the porcine gastric microbiota.

Aim:
The aim of this study was to analyse the relationship between the severity of gastric mucosal damage, gastric pH values, and the presence of lactic acid bacteria, predominantly morphologically consistent with Lactobacillus spp., using culture and cytological methods.

Methods:
A total of 20 porcine stomachs were analysed. The pH values were measured in the pars esophagea and in the glandular region of the stomach. Microbiological examination included cultivation on selective media and impression smear cytology.

Results:
The results demonstrated a decrease in pH in the pars esophagea associated with increasing lesion severity, from 5.39 ± 0.64 in score 0 lesions to 4.07 ± 0.40 in score 2 lesions (p = 0.012), whereas pH values in the glandular region remained relatively stable (mean 4.42). Lactic acid bacteria, predominantly morphologically consistent with Lactobacillus spp., were detected in all samples regardless of lesion severity.

Conclusion:
The findings suggest that local acidification of the pars esophagea is a key factor in the development of gastric lesions, whereas lactic acid bacteria, predominantly morphologically consistent with Lactobacillus spp., appear to represent an acid-tolerant but likely secondary component of the gastric microbiota.

Key words: Gastric ulceration; Lactic acid bacteria; Microbiota; Pars esophagea; Pigs.