Impact of Valerian ( <i>Valeriana officinalis</i> ) Extract Supplementation on Common Carp ( <i>Cyprinus carpio</i> L.) Growth Performance, Immune Responses, and Gene Expression

This study evaluated the effects of dietary supplementation with valerian ( Valeriana officinalis ) extract on growth performance, immune responses, and gene expression in common carp ( Cyprinus carpio ). Four experimental diets (V‐0, V‐0.25, V‐0.5, and V‐1) containing 0%, 0.25%, 0.5%, and 1% valerian extract were administered for 30 days. Dietary supplementation did not significantly influence growth performance ( p &gt; 0.05). Glutathione peroxidase (GPX) activity remained unchanged except in the high‐dose group (V‐1), while malondialdehyde (MDA) activity was significantly reduced in the V‐0.25 group ( p &lt; 0.05). Aspartate aminotransferase (AST) activity increased in the V‐1 group ( p &lt; 0.05), whereas alanine aminotransferase (ALT) activity decreased in the V‐0.25 group ( p &lt; 0.05). Albumin (ALB) levels were elevated in the V‐1 group ( p &lt; 0.05), while globulin (GLB) levels increased in all valerian‐supplemented groups ( p &lt; 0.05). Creatinine (CRT) levels rose significantly only in the V‐1 group ( p &lt; 0.05), and cholesterol levels decreased in the 0.5% and 1% groups ( p &lt; 0.05). Gene expression analysis revealed an increase in interleukin‐1 beta ( IL-1β ) expression in the V‐0.5 group ( p &lt; 0.05) but reductions in IL-10 and heat shock protein 70 ( HSP70 ) in the V‐0.25 group ( p &lt; 0.05). Superoxide dismutase (SOD) and catalase (CAT) gene expression levels significantly decreased in the groups fed with 0.25% and 0.5% valerian extract ( p &lt; 0.05), while catalase ( CAT ) gene expression levels significantly decreased in the groups fed with 0.25% and 0.5% valerian extract ( p &lt; 0.05). GPX gene expression levels declined across all experimental groups ( p &lt; 0.05). Tumor necrosis factor alpha ( TNF-α ) gene expression showed no significant changes ( p &gt; 0.05). These findings highlight the potential of valerian extract as a functional feed additive. However, further research with extended feeding durations and varying doses is required to understand its physiological effects in aquaculture better.