Comparative effects of exotic Raanan and local feeds on growth performances of Nile tilapia (Oreochromis niloticus) reared in engineered multi-constructed ponds for efficient water use

Abstract

Purpose: Growth performance of 30 randomly sampled tilapias were examined fortnightly for 12 weeks.
 Research methodology: Growth of male Oreochromis niloticus in two-by-two Completely Randomized Block Design (CRBD) with four treatments [New Water with Raanan (NWR), New Water with Local feed (NWL), Old Water with Local feed (OWL) and Old Water with Raanan (OWR)] was monitored in four ponds measuring 360 m2 each. Pond Temperature, pH, Dissolved Oxygen were assessed using the multi parameter-probe. Fish total body weights and lengths were measured using electronic scale and 30 cm rule.
 Results: Temperatures ranged from 26.2 °C (OWR) < 26.4 °C (OWL) < 26.5 °C (NWR) < 26.8 °C (NWL). Highest mean pH of 6.7 was recorded in NWR compared to the lowest (6.1) in NWL. Dissolved oxygen was 3.0 mg/l for all treatments, except in OWR (3.7 mg/l). There were significant differences among entire physicochemical parameters (p < 0.05). The NWR produced highest tilapia body weights (88.3 g) followed by OWL (47.9 g), NWL (47.1 g) and OWR (44.0 g). Final fish body lengths were in order of OWR (9.1 cm) < OWL (9.2 cm) < NWL (9.7 cm) < NWR (12.1 cm) respectively with significant variations. Raanan cultured tilapia grew better than the local feed comprised of energy sources.
 Limitations: Null hypothesis failed to confirm significant differences in fish growths (p < 0.05).
 Contribution: Use of old water is recommended in absence of fresh, if pond is completely drained/limed to eliminate leeches, tilapia eggs, fry which may infest introduced fingerlings.