Substitution of fishmeal with sunflower seed cake and moringa leaf meal and influence of feed form on the growth performance, feed utilization and profitability of Nile tilapia

This study was conducted to assess the effects of replacing fishmeal (FM) with a mixture of sunflower seed cake (SSC) and Moringa oleifera lea meal (MLM) as well as the effects of feed form on growth performance, feed utilization and profitability of Nile tilapia. In the first experiment six diets (D1, D2, D3, D4, D5 and C1) were formulated. In D1 FM was replaced with 37.5 % SSC + 37.5% MLM. In D2 FM was replaced with 18.75 % SSC + 56.25% MLM. In D3 FM was replaced with 43.75 % SSC + 43.75% MLM. In D4 FM was replaced with 21.87 % SSC + 55.63% MLM. In D5 FM was replaced with 75 % SSC alone while in C1 FM was not replaced. The control was a commercial diet (C2). The diets were randomly allocated to 21 small plastic tanks. Each tank was stocked with 10 sex-reversed male Nile tilapia fingerings (Oreochromis niloticus) with average weight of 1.17 ± 0.65 g. The experiment took 90 days. In the second experiment, the best feed from the first experiment was used to make two forms of diets (mash and pellets) which were compared in on-station and on-farm studies. For the on-station study 10 concrete tanks were randomly allocated to pelleted and mash diets. Each tank was stocked with 12 sex-reversed male Nile tilapia fingerings with an average weight of 2.1 ± 0.4. In the on-farm study 10 earthen ponds of five farmers were randomly allocated to mash and pelleted feeds five ponds per diet and stocked with sex-reversed male Nile tilapia fingerlings with average weight of 1.3 ± 0.1 g. For both on-station and on-farm studies the experimental period was eight months. In the first experiment the mean weight gain of fingerlings fed D2 (10.19 ± 1.09 g) did not differ (P > 0.05) from those fed control diet (C2) (11.54 ± 1.77 g). The fingerlings fed C1 had lower average weight gain (9.60 ± 1.14 g) compared to those fed C2 and D2, but slightly higher than those fed diets D3 (9.23 ± 1.02 g) and D5 (8.76 ± 1.00 g). The results of the second experiment for the on-station study showed that the fish fed pellets had higher (P ≤ 0.05) mean weight gain (290.92 ± 4.52 g), growth rate (1.09 ± 0.02 g/d) and condition factor (1.88 ± 0.03), lower FCR (1.99 ± 0.03) and higher estimated annual yield (4,727.19 ± 220.45 kg/ha/year) and gross margin (TZS 18,116,040.21) than those fed mash diet. Similarly, for the on-farm study, the fish fed pelleted diet had higher growth performance, lower FCR and higher annual gross margin than those fed mash feed. It is concluded that fishmeal can be replaced by the mixture of sunflower seed cake (7.5%) and Moringa leaf meal (22.5%) up to 75% in Nile tilapia diets. The use of pelleted diet significantly improves growth performance, feed utilizations efficiency and gross margin compared to mash diet.