# Probiotic Gordonia alkanivorans Enhances Phagocytic Function of Porcine Alveolar Macrophages and Modulates Immune Responses in Piglets

## TL;DR

This study shows that the probiotic Gordonia alkanivorans boosts piglet immunity by improving macrophage function and gut health.

## Contribution

The novel finding is that G. alkanivorans significantly enhances phagocytic activity and modulates immune responses in piglets.

## Key findings

- G. alkanivorans increased phagocytic efficiency of PAMs by 98.5% against PRRSV and 2.31- to 13.46-fold against E. coli.
- Dietary G. alkanivorans elevated antibody-positive rates against classical swine fever and pseudorabies viruses.
- It improved intestinal microbial diversity and modulated serum cytokine profiles in piglets.

## Abstract

As a probiotic strain rich in glycolipid, Gordonia alkanivorans (G. alkanivorans) exhibits significant potential for enhancing animal immunity. Using in vitro porcine alveolar macrophage (PAM) models and in vivo animal experiments, this study demonstrated that G. alkanivorans significantly enhanced the phagocytic capacity of PAMs against porcine reproductive and respiratory syndrome virus (PRRSV) and Escherichia coli (E. coli). Furthermore, it increased the positive rates of virus-specific antibody in piglets, modulated serum cytokine profiles, and improved intestinal microbial diversity. Collectively, G. alkanivorans exerts potent antiviral activity and improves piglet health by the enhancement of immune function and modulation of intestinal microecology.

This study aimed to evaluate effect of Gordonia alkanivorans on phagocytic activity of porcine alveolar macrophages (PAMs) and immune function in piglets. Quantitative PCR and fluorescence tracing were used to measure phagocytic efficiency of G. alkanivorans-intervened PAMs against PRRSV and E. coli. Sixty-four 45-day-old cross-bred piglets with equal sex were randomly divided into four groups (n = 16/group). Growth performance, immune function, and intestinal flora were analyzed. G. alkanivorans extract exhibited half cytotoxic concentration of 36.43 mg/mL, half effective concentration of 0.1009 mg/mL, and half inhibitory concentration of 0.0043 mg/mL in PAMs, significantly increasing their phagocytic efficiency by 98.5% against PRRSV and 2.31- to 13.46-fold against E. coli. Dietary supplementation with G. alkanivorans elevated antibody-positive rates against classical swine fever virus (47.92%) and pseudorabies virus (14.58%), modified serum cytokine: Interleukin (IL)-1β, IL-2, Tumor Necrosis Factor -α, Interferon (IFN)-α, IFN-γ, IL-4, and IL-10 (−144.51% to +191.72%). It increased intestinal operational taxonomic units by 152%, the Shannon index by 14.62%, and the Chao index by 11.37%, while reducing the Firmicutes/Bacteroidetes ratio by 713.90%. In conclusion, G. alkanivorans enhances immunity and antiviral activity in piglets by gut and immune regulation.