# Dietary Astragalus Crude Extract Boosts Piglet Growth and Mitigates Weaning Stress by Enhancing Antioxidant Activity, Improving Immunity, and Modulating Intestinal Microbiota

## TL;DR

Astragalus extract improves piglet growth and reduces weaning stress by boosting antioxidants, immunity, and gut health.

## Contribution

Astragalus crude extract is shown to be a safe and effective alternative to antibiotics in weaned piglets.

## Key findings

- Astragalus extract improved growth performance and reduced diarrhea in weaned piglets.
- The extract enhanced antioxidant capacity and modulated gut microbiota composition.
- Astragalus extract upregulated intestinal tight junction proteins and immune markers.

## Abstract

Weaning stress induces diarrhea and growth retardation in piglets. Astragalus has been demonstrated to exert bioactive properties, including antioxidant, anti-inflammatory, and immunomodulatory activities. This study investigated whether dietary supplementation with Astragalus crude extract could serve as a safe and effective alternative to antibiotics in weaned piglets. The results suggested that Astragalus crude extract supplementation mitigated weaning stress and improved the growth performance by enhancing antioxidant capacity, improving immune response, and modulating the microbiota composition in piglets. Its efficacy is comparable to that of antibiotics. This study provides a theoretical basis and practical support for the application of Astragalus to improve the intestinal health of weaned piglets.

Astragalus is a traditional Chinese medicine that contains various bioactive compounds, which exert antioxidant and immunomodulatory properties. This research aimed to investigate the impacts of Astragalus crude extract on growth performance, nutrient digestibility, immune response, and intestinal health in weaned piglets. Sixty crossbred weaned piglets at 28 days of age (8.12 ± 0.14 kg) were allocated into three dietary treatments: a control group fed a corn–soybean meal-based diet (CON), an antibiotic group received the basal diet with 1000 mg/kg aureomycin (AN), and a treatment group administered the basal diet with 500 mg/kg Astragalus crude extract (CE), with 5 replicates per group, 4 piglets per replicate. The experimental trial lasted for 28 days. Feed intake and body weight were recorded to evaluate growth performance. Blood, intestine, and liver tissue samples were collected for the analysis of antioxidant capacity and gene expression. Compared to the CON group, supplementation with CE or AN significantly enhanced growth performance and decreased diarrhea incidence on days 0–14, whereas only CE tended to improve crude protein digestibility. Piglets supplemented with AN or CE showed improved antioxidant capacity and immune response relative to the CON group, as evidenced by increased liver and intestinal antioxidant enzyme activities, upregulated intestinal antioxidant gene expression, and enhanced plasma immunoglobulin A levels. Further, the upregulated intestinal tight junction protein expression was observed in CE or AN groups compared with the CON. Notably, dietary CE significantly modulated gut microbiota composition, particularly enriching the genera Blautia, Turicibacter, Agathobacter, and Clostridium. These findings indicate that dietary Astragalus crude extract promotes the gut health of weaned piglets by reducing oxidative stress and modulating gut microbiota composition, thereby decreasing diarrhea incidence and improving growth performance.