Mugwort Leaf Powder ( <i>Artemisia argyi</i> ) Alleviates Lipid Metabolism Disorders and Intestinal Health of Common Carp ( <i>Cyprinus carpio</i> ) Fed High‐Fat Diets

Mugwort leaf powder (MLP), as a typical Chinese herbal medicine containing lots of flavonoids and polysaccharides, has strong anti-inflammatory and immune effects. However, there are relatively few studies on the use of MLP in aquatic animals fed high-fat (HF) diets (HFDs), especially in terms of lipid metabolism and intestinal health. To investigate the impacts of MLP on the growth performance and health status of common carp fed HFDs, common carp were provided with a basal diet, an HFD, and the HFDs enriched with 0.6%, 1.2%, 1.8%, and 2.4% MLP for 8 weeks. Dietary supplementation with 0.6%-1.2% MLP enhanced fish growth and feed utilization compared to the HF group (<i>p</i> < 0.05). Supplementation with over 1.2% MLP increased villus height and digestive enzyme activities (<i>p</i> < 0.05). Supplementation with 1.2% MLP upregulated intestinal anti-inflammatory gene expression and decreased serum triglyceride levels (<i>p</i> < 0.05). Moreover, MLP significantly mitigated the degree of hepatocyte vacuolation and reduced adipocyte size (<i>p</i> < 0.05). Supplementation with over 1.2% MLP decreased the crude lipid, triglyceride, and cholesterol levels in the hepatopancreas, as well as downregulated the lipid synthesis gene expression of <i>fas</i> and upregulated the lipolysis gene expression of <i>cpt1</i> in the hepatopancreas (<i>p</i> < 0.05). The gene expression related to lipid synthesis in adipose tissue also exhibited a downregulated tendency (<i>p</i> < 0.05). Combining the quadratic regression results of the above indices, this study concluded that supplementation with 0.92%-2.17% MLP positively influenced the growth, intestinal well-being, and lipid metabolism of common carp fed HFDs.