Assessment of Dietary Protein Requirements for Optimum Growth of Tilapia in Outdoor Ponds in Katsina State

Defining the optimum dietary protein level for Nile tilapia under the thermal and water quality conditions specific to outdoor ponds in North West Nigeria is critical for developing cost-effective feed formulations for local producers. This study assesses the effect of five dietary protein levels, specifically 25%, 30%, 35%, 40%, and 45% crude protein, on the growth performance, feed utilisation, and body composition of Nile tilapia reared in outdoor earthen ponds at a state aquaculture demonstration farm in Katsina State over a 12-week period. Ninety fingerlings with an initial mean weight of 6.8 g were stocked per pond across 15 ponds and fed experimental diets twice daily. Biweekly weight measurements and fortnightly water quality assessments were conducted throughout the trial. Results showed that fish fed the 35% crude protein diet achieved the highest specific growth rate and protein efficiency ratio without significant differences from the 40% diet. Feed conversion ratio was significantly poorer in the 45% protein group, attributed to nitrogen wastage. Body fat content increased inversely with dietary protein level above 35%. The study recommends 35% crude protein as the optimal level for Nile tilapia production in outdoor earthen ponds under the climatic conditions of Katsina State, potentially reducing feed formulation costs relative to higher-protein commercial diets currently marketed to tilapia farmers in North West Nigeria.

Keywords: dietary protein, Oreochromis niloticus, growth performance, earthen pond, Katsina State