Effects of Verbena and Polygonum cuspidatum on growth performance, immune functions, cecal microbiota, and brain metabolites in Sansui ducks

Background Verbena and Polygonum cuspidatum, recognized for their antioxidant and immunomodulatory properties, have demonstrated potential benefits. However, the specific mechanisms by which these herbs impact poultry health, particularly regarding alterations in gut microbiota and brain metabolite profiles, remain insufficiently investigated. This study aimed to investigate the effects of Verbena and Polygonum cuspidatum supplementation on the growth performance, immune function, cecal microbiota, and brain metabolites in Sansui ducks. Methods A total of 216 one-day-old ducks were randomly assigned to three treatment groups for a 35-day trial, each with 6 replicates of 12 ducks. The ducks were fed a basal diet (T3), a basal diet supplemented with 40mg/kg Verbena (T1), and a basal diet supplemented with 40mg/kg Polygonum cuspidatum (T2). Results The results showed that both herbs significantly increased body weight, IgG, and IgM levels, while decreasing the feed conversion ratio (FCR) compared to the control group (T3) (P < 0.05) Notably, Verbena supplementation increased the relative abundance of beneficial bacteria, such as Bacteroidetes and Saccharibacteria , and significantly decreased the relative abundance of pathogenic bacteria such as Actinobacteria ompared to the control group (P < 0.05). Polygonum cuspidatum treatment increased the relative abundance of Megamonas compared to the control group (P < 0.05). Additionally, Verbena treatment increased the concentration of Gln and decreased the concentrations of GABA, Tyr, and Ach compared to the control group (P < 0.05). Polygonum cuspidatum treatment increased 5-HIAA concentration compared to the control group (P < 0.05). Further correlation analysis highlighted a significant link between gut microbiota ( Villanella, Anaerosporobacter, Anaerofustis , and Flavonifracter ) changes and brain metabolites (GABA, Ach, and Glu), suggesting the potential influence of these herbs through the microbiota-gut-brain axis. Conclusion This study provides novel insights into how dietary herbal supplements can improve poultry health by modulating both gut and brain biochemistry, offering a promising natural alternative to antibiotics in poultry production.