Title : Effects of probiotic doses and stocking density on water quality and some growth performances of Clarias gariepinus fingerlings
Abstract:
Stocking density is a very important factor in aquaculture. In African catfish (Clarias gariepinus), high densities often lead to a deterioration in water quality, slower growth, and increased mortality. This study, conducted from April 20 to June 20, 2025, at the Grenier d'Afrique farm (Nkolnda, Yaoundé), aimed to evaluate the effect of probiotics on water quality and growth performance of fry raised at different stocking densities. A total of 2,160 fries (1 ± 0.3 g) were divided into three treatments: 0 g/m³ (control), 3 g/m³ and 5 g/m³ of the probiotic AQUAcare (Skretting), containing Bacillus subtilis, B. amyloliquefaciens, B. pumilus, and B. licheniformis. Each treatment was applied at three densities (2, 4, and 6 fry/L) in duplicate. After 60 days, NO?? concentrations did not vary significantly (p > 0.05), while NH?? concentrations increased significantly with density (p < 0.05). The best zootechnical performance was recorded with 3 g/m³ at 2 fry/L: weight gain (63.70 ± 3.67 g), average daily gain (1.06 ± 0.06 g/day), survival rate (88.33 ± 2.35%), and feed conversion ratio (1.33 ± 0.11). The highest specific growth rate (SGR) was observed with 5 g/m³–2 al/L. However, the high-density dose of 5 g/m³ (6 al/L) generated the highest production cost (2,846.40 CFA francs/kg) and negative profitability. Thus, the application of 3 g/m³ of low-density probiotics improves growth and survival, while moderate density optimizes profitability.
Keywords: Clarias gariepinus, probiotics, growth performance, water quality, stocking density, profitability
