Dietary impact of Alfalfa on growth performance, biochemical profile, and resistance against Aeromonas hydrophila in fingerlings of common carp

The present study investigates the effects of dietary alfalfa, Medicago sativa leaves, on growth performance, carcass composition, enzymatic activity, biochemical indices, intestinal histomorphometry, and disease resistance in fingerlings of common carp, Cyprinus carpio L. A feeding trial of 60 days was carried out in which common carp fingerlings were fed on experimental diets supplemented with alfalfa extract at rates of 0.0% (T₀) control, 0.25% (T₁), 0.50% (T₂), 0.75% (T₃), and 1.0% (T₄). At the end of the feeding trial, specific growth rate, protein efficiency ratio, and feed conversion ratio improved significantly (P < 0.05) in groups fed on diet supplemented with alfalfa in a dose-dependent manner. The blood biochemical parameters and the activity of the digestive enzymes were significantly (P < 0.05) elevated in the alfalfa supplemented groups in a dose-dependent manner. Additionally, T₄ had significantly (P < 0.05) more protein in fish carcasses than the control group. Intestinal histomorphometry and the relative percent survival following the challenge trial with Aeromonas hydrophila were also significantly (P < 0.05) enhanced by dietary alfalfa. The study concludes that alfalfa extract possesses antioxidant and immune-enhancing potential, which by improving growth and increasing the capacity to combat bacterial infections in fish proves beneficial for sustainable aquaculture.