Effects of Fermented Tomato Meal Inclusion in Diets on the Growth and Feed Utilization of Nile Tilapia (Oreochromis niloticus)

Abstract

The need for cost-effective feed ingredients for Nile tilapia has driven the exploration of agro-industrial by-products, including fermented plant materials, as alternative feed ingredients. This study evaluated the effects of dietary inclusion levels of fermented tomato meal on growth performance, feed utilization efficiency, and protein retention of Nile tilapia (Oreochromis niloticus). A 40-day feeding trial was conducted using a completely randomized design with four dietary treatments and three replicates. The treatments were A (5% fermented tomato meal + 15% soybean meal), B (10% fermented tomato meal + 10% soybean meal), C (15% fermented tomato meal + 5% soybean meal), and D (commercial feed). Fish with an initial body weight of 10.40 ± 1.06 g were stocked at ten fish per aquarium and fed at 5% biomass day⁻¹. The observed parameters included weight gain, specific growth rate, feed conversion ratio, feed efficiency, survival rate, and protein retention. Dietary treatment significantly affected weight gain and protein retention (P < 0.05) but had no significant effect on specific growth rate, feed conversion ratio, feed efficiency and survival rate (P > 0.05). Among the formulated diets, treatment B produced the most balanced feed utilization performance, with a weight gain of 3.88 g, a feed conversion ratio of 5.04, feed efficiency of 20.62%, and protein retention of 79.58%. These findings indicate that fermented tomato meal can partially replace soybean meal at a 10% inclusion level, making it a promising ingredient for Nile tilapia diets.