Dietary supplementation of encapsulated organic acids enhances performance and modulates immune regulation and morphology of jejunal mucosa in piglets

The aim of the study was to test two encapsulated regimens containing organic acids and/or zinc oxide (ZnO) on weaned piglet performance and jejunal mucosa morphology and immunity. For that, weaned piglets were allocated to treatments including control, supplemented with encapsulated organic acids (ACID group), and supplemented with organic acids and ZnO, both encapsulated (ACIDplus group). Antibiotics were used at similar concentrations in all groups during the first two weeks, but withdrawn from the ACIDplus group during the last three weeks of the experiment. ZnO was given with feed in the Control and ACID groups only during the first two weeks. The experimental period lasted 5 weeks. Piglets from the ACID group exhibited higher average daily gain compared to other groups during the last 3 weeks of the experiment (P < 0.05). The ACIDplus group performed similarly with controls. The mucosal height of jejunum was higher in both ACID (P < 0.01) and ACIDplus groups compared to controls (P < 0.05). Immunohistochemical analysis of jejunal mucosa, showed higher numbers of neutrophils in ACID and ACIDplus groups compared to controls (P < 0.01 and P < 0.001, respectively). Treatments had the opposite effect on mucosal regulatory T-cells (Foxp3-positive cells) in jejunum, being higher (P < 0.001) in control group compared to ACID and ACIDplus groups. The number of CD3-positive cells was higher (P < 0.05) in the ACIDplus and control groups compared to the ACID group. In conclusion, the encapsulated products used had beneficial effects on growth performance coexisting with improvements on jejunal histomorphology and modulation of mucosal immunity.