Effect of the water quality on the growth rate of Nile tilapia (Oreocromis niloticus) in aquaculture

Abstract

The increasing human population has led to an increase in the demand for sustainable protein sources has heightened interest in optimizing aquaculture practices, particularly regarding water resource utilization. This research examined the comparative effects of three readily available water sources on Nile tilapia (Oreochromis niloticus) growth performance in controlled aquaculture conditions. The experimental design involved 1,440 juvenile fish (0.3±0.14g initial weight) in three treatment tanks (treated tap water, rainwater, and well/bore hole water treatments), each with four replicates. Each tank was stocked with 120 individuals. Fish were fed a commercial diet containing 40% protein at 5% average body weight daily. Over an eight-week period, Growth performance was assessed through weekly weight measurements and specific growth rate (SGR) calculations, while survival rates were recorded daily. Statistical analyses included ANOVA for growth comparisons, Pearson correlation analysis for water quality relationships, and Chi-square tests for survival rate differences. Results demonstrated significant differences in both growth performance and survival rates among water sources. Well water produced superior growth outcomes with the highest specific growth rate (4.23%/day) and final body weights (6.27±0.23g), representing 56% and 86% improvements over treated tap water (3.51%/day; 4.02±0.19g) and rainwater (3.12%/day; 3.37±0.17g), respectively. ANOVA confirmed these differences were statistically significant (F₂,₉ = 12.89, P < 0.01). The superior performance in well water was attributed to optimal temperature conditions (24.90-29.50°C), higher dissolved oxygen levels (7.375±0.2987 mg/L), and reduced osmoregulatory costs due to appropriate mineral content. Survival rates varied significantly across treatments (χ² = 18.45, P < 0.001), with treated tap water achieving the highest survival (91.2%), followed by well water (84%) and rainwater (75.4%). The stability of water quality parameters in treated tap water contributed to minimal disease pressure and stress factors. Correlation analysis revealed temperature as the strongest predictor of growth performance (r = 0.847, P < 0.001), followed by dissolved oxygen (r = 0.623, P < 0.01), while pH showed no significant correlation with growth (r = -0.234, P = 0.187). The study demonstrates clear trade-offs between growth optimization and survival maximization across different water sources. Well water offers superior growth potential for commercial operations prioritizing production efficiency, while treated tap water provides reliable outcomes with minimal mortality risk. Rainwater requires significant conditioning before use in intensive aquaculture systems due to poor performance in both growth and survival metrics.