Dietary fermented Artemisia argyi enhances growth performance, hepatic antioxidant activity, and intestinal health in Hongyu roosters.

The Hongyu rooster, prized in China's poultry industry for its tender meat, high protein, and low fat content, represents an important production breed. This study evaluated the effects of Lactobacillus plantarum-fermented Artemisia argyi (AA) as a dietary supplement on growth performance, intestinal health, and antioxidant capacity. The results showed that fermented AA significantly increased the daily weight gain and reduced the feed-to-gain ratio in Hongyu roosters (P < 0.05), with the 1 % group exhibiting the most substantial effect. Furthermore, fermented AA enhanced intestinal barrier functions by upregulating mRNA expression of Claudin-1, JAM-2, Mucin-2, and Occludin, while downregulating Claudin-2 (P < 0.05). Fermented AA also alleviated inflammation by inhibiting pro-inflammatory cytokines, promoting IL-10, and regulating the TLR4/MyD88/NF-κB pathway, with the 3 % group showing the strongest effect. Intestinal morphology and function were improved through increased villus height, higher villus height-to-crypt depth ratio, reduced crypt depth, elevated short-chain fatty acids, and greater jejunal sIgA and IgM concentrations. Antioxidant defense was enhanced by suppression of Keap1 and upregulation of CAT, SOD-1, Nrf2, and GPx-1. Gut microbiota composition was also reshaped, with increased Bacteroidetes and reduced Firmicutes. In conclusion, fermented AA supplementation improved growth, intestinal integrity, antioxidant capacity, and immune function in Hongyu roosters, highlighting its potential as a functional feed additive.