Dietary Artemisia vulgaris meal improved growth performance, gut microbes, and immunity of growing Rex rabbits

Artemisia vulgaris (A. vulgaris) is an edible plant showing antioxidant and antibacterial effects, but its effect as a feed additive or forage source on the herbivore growth and health is unclear. This study aimed to investigate the effect of A. vulgaris meal supplementation on the growth performance, gut microbes, and immune function in rabbits. A total of 120 growing Rex rabbits were randomly allocated into 4 treatments with 6 replicates per 5 rabbits each. There were four experimental diets containing A. vulgaris meal at doses of 0, 3.0, 6.0 or 9.0%, respectively. The experiment lasted for 70 days. The results showed that diets supplemented with A. vulgaris meal improved the rabbits' feed intake, body weight gain, and decreased feed conversion ratio (P < 0.05). Linear and quadratic responses were found between the growth parameters and the herbal meal doses (P <= 0.002). A. vulgaris meal also improved gut microbe populations by increasing Lactobacilli and Bifidobacteria, and decreasing E. coli, C. perfringens, Salmonella, and Gram-negative bacteria (P < 0.05), and linear and quadratic dose-dependent advantages were exhibited for these microbes (P <= 0.013). Furthermore, blood levels of IgA, IgM, and lymphocytes of bursale, thymus, CD4 and CD8 were increased by the treatments containing A. vulgaris meal (P < 0.05), and linear dose-dependent effect was found on these immune indexes (P < 0.001). Diet supplemented with A. vulgaris meal is effective in improving growth, gut microbes, and immunity of Rex rabbits.