Influence of Culture Tank Colours on the Water Quality, Growth Performance and Feed Utilization of Oreochromis niloticus (Linnaeus, 1758) Juveniles

Abstract

The study was conducted over a period of fifty-six (56) days to investigate the effects of different colours of culture tanks on the water quality, growth, and feed utilization of Nile tilapia (Oreochromis niloticus) juveniles. O. niloticus of mean body weight of 8.5g were stocked and fed twice daily with a commercial diet containing 42% crude protein. The experiment had four treatments based on tank colours; white, green, black and blue coloured tanks. Some water quality indices were assessed once in a week while the fish were weighed at the end of the experiment to compute the performance indices. The data were presented using mean and standard error and comparative analysis was done using one way ANOVA at 95% confidence interval with Duncan multiple range test as the follow up test. The water quality parameters examined during the study were not significantly different among the treatments. All the selected water quality parameters were within the acceptable range for tropical fish culture. While there was no significant difference in final weight, weight gain, percentage weight gain, and specific growth rate among the treatments, black tanks showed slightly higher values with 10.89±0.89 g, 2.54±0.94g, 30.47±11.43%, and 0.47±0.16%/day, respectively. Higher feed intake and FCR were recorded in green tank (10.08±0.61 g and 7.92±2.70 respectively) and the least was observed in black tank (9.32±0.12g and 4.23±1.51). The percentage survival of the fish was different significantly among the treatments (P<0.05). Fish reared in white background showed the highest survival (100%) which was different significantly from all other treatments. The blue and black tanks showed slightly higher values of viscerosomatic index and hepatosomatic index with 7.22±1.00% and 2.02±0.25%, respectively, while black and white tanks had the least values with 4.44±1.11% and 1.64±0.15%, respectively. The results showed that O. niloticus juveniles can be reared in all the tanks with no negative implication on their performances. However, black and white tanks showed better potential towards improved growth and feed utilization, while white tank led to better survival rate and tended towards better well-being as indicated by the skin pigmentation and hepatosmatic index. Therefore, rearing of O. niloticus juvenile in white tank is recommended over other colours.