Growth Responses of Nile Tilapia (Oreochromis niloticus) Exposed to Different Concentrations of Detergents Powder

The study on the growth responses of Oreochromis niloticus exposed to different concentrations of detergents powder was carried-out using a 30 day renewal bioassay in triplicates. A total of 360 Oreochromis niloticus fingerlings, with a mean bogy weight of 18.2 ± 3.02 g were used for the study. Ten fingerlings were stocked in each aquarium containing 10 litres of water and exposed to 0, 1. 5 and 9 ml concentrations of detergents. The DWG, PWG, SGR and SR (growth responses) of the test fish varied significantly between the fish groups exposed to different concentrations of detergent “A”, “B” and “C” at p<0.05, having homogenous variances in each group (p>0.05). The DWG, SGR, SR and PWG of the test fish decreased with increase in the concentration of each detergent, with the highest growth reduction of 0.50 ± 0.05 g (DWG), 1.34 ± 0.11% (SGR), 46.67 ± 11.55% (SR) and 33.14 ± 2.21% (PWG) for detergent “A”; 0.41 ± 0.06 g (DWG), 0.50 ± 0.06% (SGR), 36.67 ± 5.77% (SR) and 28.96 ± 2.77% (PWG) for detergent “B”; 0.39 ± 0.01 g (DWG), 0.47 ± 0.02% (SGR), 30.00 ± 10.00% (SR) and 27.85 ± 0.77% (PWG) for detergent “C” observed at the highest concentration, compared to 0.81± 0.10 g (DWG), 1.98 ± 0.19% (SGR), 90.00 ± 10.00% (SR) and 44.73 ± 3.10% (PWG) for the control group. When the fingerlings were exposed to the detergents, behavioural changes like; erratic swimming, loss of equilibrium, poor feeding, change in colour and respiratory disturbances were observed. The fish growth had a decreasing sequence of detergent A > B > C, as a result, the fish group exposed to detergent “A” had the best growth performance aside from the control group, while detergent “C” group had the worse growth. This indicates that detergent “A” is the least toxic, while detergent “C” is the most toxic. This findings indicated that detergents affected the growth of the test fish. As a result of the effect of detergents on the growth of fish, it is necessary that adequate management strategies like; continuous monitoring of aquatic eco-system and placing ban on indiscriminate discharge of detergent effluents into waterways are put in place. It is also recommended that more studies on the haematological, histological and enzymes alterations of Oreochromis niloticus exposed to different concentrations of detergents are carried-out, so as to further reveal the adverse effect of detergents on aquatic organisms.