Preliminary Insights Into the Incorporation of Common Hop (Humulus lupulus L.) Into the Fish Feed: Effect on Growth Performance, Whole‐Body Proximate Composition, Fillet Fatty Acid Composition, Blood Biochemical, and Antioxidant Properties of Common Carp (Cyprinus carpio L.)

Abstract

The present study assessed the effect of common hop (Humulus lupulus L.) extract on common carp (Cyprinus carpio L.). Fish (initial weight of 32.22 ± 0.65 g) were divided into three groups and fed diets containing 0 (control), 0.75 g (H0.75), and 1.5 g (H1.5) of common hop extract per kg of isonitrogenous, isolipidic, and isoenergetic commercial diet for 8 weeks. No significant differences in growth performance across treatments were observed (p > 0.05). Protein content in whole‐body proximate composition increased significantly in H1.5 compared to the control (p < 0.05). The H0.75 showed a significant increase in lipid peroxidation (LPO) and reduced glutathione (GSH) levels compared to the control (p < 0.05). While H1.5 had higher acetylcholinesterase (AChE) than group H0.75 (p < 0.05), no significant change was observed in AChE, catalase (CAT), and superoxide dismutase (SOD) activities in treated groups compared to the control (p > 0.05). Blood biochemical indices, alanine aminotransferase (ALT), and alkaline phosphatase (ALP) were significantly lower in H0.75 and H1.5 than in the control (p < 0.05), while lactate dehydrogenase (LDH) increased significantly in H1.5 compared to the control (p < 0.05). Cholesterol, triglyceride (TG), and the number of white blood cells (WBCs) showed no significant differences across treatments (p > 0.05). H0.75 significantly increased the proportion of polyunsaturated fatty acids (PUFAs) like α‐linolenic acid, docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA; p < 0.05), and both H0.75 and H1.5 raised considerably the value of oleic acid and eicosatrienoic acid compared with the control (p < 0.05); in contrast, eicosapentaenoic acid (EPA) was decreased significantly by H1.5 compared to the control (p < 0.05). Supplementation of the common hop at 0.75 and 1.5 g kg−1 positively affected farmed carp.