Effect of dietary sea grapes Caulerpa lentifera supplementation in the diet on the growth performance, survival rate, and feed utilization of Nile tilapia Oreochromis niloticus

Abstract

Utilization of fermented natural feed ingredients has emerged as a promising strategy to enhance nutrient bioavailability and increase the functional value of aquafeeds. This study evaluated the effects of dietary supplementation with fermented sea grapes (Caulerpa lentifera) on the production performance of Nile tilapia juveniles and determined the optimum dietary inclusion level. The experiment was conducted from September to November 2025 at the Experimental Animal Unit, Faculty of Veterinary Medicine, Universitas Syiah Kuala, Banda Aceh, Indonesia.  A completely randomized design (CRD) with a single-factor arrangement was employed, consisting of five dietary inclusion levels of fermented C. lentifera (0, 0.5, 1.0, 1.5, and 2.0%), each with four replicates, over a 60-day feeding trial. Growth performance of fish was assessed based on weight gain (WG), daily growth rate (DGR), specific growth rate (SGR), feed conversion ratio (FCR), and survival rate (SR). Data were analyzed using one-way analysis of variance (ANOVA), followed by Duncan's multiple range test. Dietary supplementation with fermented C. lentifera significantly improved growth performance of tilapia compared with the control (P < 0.05). Fish fed with diet containing 2.0% fermented C. lentifera exhibited the highest weight gain (15.50 g), DGR (0.26 g day⁻¹), and SGR (4.39% day⁻¹),  lowest FCR values (1.11). Survival rate (85–100%) was high across all treatments, indicating that dietary supplementation did not adversely affect fish health and survival. Water quality parameters remained within the recommended range for Nile tilapia culture throughout the experimental period. These findings show that fermented C. lentifera is a promising, locally available functional feed ingredient that can be used to improve growth performance and feed utilization in Nile tilapia juveniles. Under the conditions of the present study, a dietary inclusion level of 2.0% fermented C. lentifera was found to be the optimum level for maximizing production performance in Nile tilapia aquaculture.