Effect of Fermented Rice Bran as Feed Substitute on Saline-Reared Nile Tilapia (Oreochromis niloticus)

Abstract

Background: The expansion of tilapia aquaculture in brackish-water ponds has emerged as a promising strategy for the productive and sustainable utilisation of coastal land. Nevertheless, the success of aquaculture systems depends not only on favourable environmental conditions but also, to a considerable extent, on effective feed management practices. Aims: This study aimed to evaluate the effect of fermented rice bran as a substitute feed ingredient on the growth performance, feed conversion efficiency and survival rate of saline-reared Nile tilapia (Oreochromis niloticus). Study Design: The study used an experimental method with a completely randomised design (CRD) comprising four treatments and three replications. Place and Duration of Study: The experiment was conducted at the fish pond of SMKN 1 Mananggu, Kramat Village, Mananggu District, Boalemo Regency, Indonesia, for 56 days from April to May 2026. Methodology: Saline-reared Nile tilapia with an average initial weight of approximately 10 g were stocked into 12 experimental units. Four dietary treatments were applied: P0 (100% commercial feed as the control), P1 (20% fermented rice bran substitution), P2 (30% fermented rice bran substitution) and P3 (40% fermented rice bran substitution). Fish were fed at 3% of their biomass three times daily. Growth performance was evaluated based on absolute weight gain, absolute length gain, specific growth rate (SGR), feed conversion ratio (FCR) and survival rate (SR). Data were analysed using one-way analysis of variance (ANOVA) at a 95% confidence level. Results: Dietary inclusion of fermented rice bran significantly improved absolute weight gain, absolute length gain, specific growth rate and feed conversion ratio (P < 0.05). The best performance was recorded in treatment P3, which produced an absolute weight gain of 20.23 g, an absolute length gain of 8.10 cm, an SGR of 1.98% day⁻¹, a survival rate of 80.83% and the lowest FCR value of 0.38. In contrast, the control treatment (P0) yielded the lowest performance, with an absolute weight gain of 12.90 g, an absolute length gain of 4.60 cm, an SGR of 1.48% day⁻¹, a survival rate of 75.67% and an FCR of 0.81. However, the treatments had no significant effect on fish survival rate (P > 0.05). Conclusion: Fermented rice bran can be used as an alternative feed ingredient for saline Nile tilapia culture. The inclusion level of 40% fermented rice bran provided the best growth performance and feed utilisation efficiency, indicating its potential as a cost-effective, locally available and sustainable feed ingredient for brackish-water aquaculture.