Management system-dependent alterations in colonic mucosal architecture of swine: An Alcian Blue histochemistry and histomorphometric analysis of goblet cell density, epithelial height, and mucin-stromal ratio.

Abstract

Background and aim: Swine management systems can influence intestinal morphology, epithelial organization, and mucosal secretory activity through differences in environmental exposure, nutrition, hygiene, and husbandry practices. However, comparative histological evaluations of colonic mucin architecture among commercial swine production systems remain limited. This study aimed to compare goblet cell density, epithelial height, and mucin-stromal ratio in the colon of swine raised under beta-agonist-free, hygienic, and free-range management systems using Alcian Blue histochemistry and quantitative histomorphometric analysis.

Materials and methods: Colonic tissue samples were collected from clinically healthy market-weight swine raised under beta-agonist-free, hygienic, and free-range conditions (n = 10 per group). Tissue sections were fixed in 10% neutral buffered formalin, embedded in paraffin, and stained with Alcian Blue (pH 2.5) to visualize acidic mucins. Quantitative histomorphometric analyses were performed using ImageJ/Fiji software to determine goblet cell density, epithelial height, and mucin-stromal ratio. Statistical analysis was performed using one-way analysis of variance followed by Tukey's honestly significant difference test, and significance was defined as p < 0.05.

Results: Significant differences in colonic mucosal architecture were observed among the three management systems. Swine raised under the beta-agonist-free system exhibited significantly greater epithelial height (252.43 ± 17.27 µm) compared with hygienic (206.27 ± 20.66 µm) and free-range swine (228.84 ± 18.42 µm) (p < 0.05). Goblet cell density was also highest in the beta-agonist-free group (46.76 ± 7.16 cells/field), followed by the free-range and hygienic groups. The mucin-stromal ratio was significantly elevated in beta-agonist-free swine (1.82 ± 0.14) compared with free-range (1.43 ± 0.12) and hygienic swine (1.09 ± 0.10) (p < 0.05). Positive correlations were observed among epithelial height, goblet cell density, and mucin-stromal ratio.

Conclusion: Different swine management systems are associated with measurable alterations in colonic mucosal architecture. Beta-agonist-free swine demonstrated enhanced epithelial development, increased goblet cell abundance, and higher mucin-stromal ratio values, suggesting distinct structural adaptations of the colonic mucosa associated with production practices. The mucin-stromal ratio may serve as a useful integrative histomorphometric indicator for evaluating intestinal mucosal organization in swine.