Abstract:
Episodes of low concentrations of dissolved oxygen (DO) and high concentrations of ammonia are major causes of fish stress, which in return, they reduce growth and increase mortality rates in aquaculture ponds. This study measured the effects of water de-stratification on dissolved oxygen and ammonia concentrations for tilapia at culture system Estimation of water quality parameters ammonia and dissolved oxygen levels in tilapia fish fingerlings It was conducted between Augusts and September 2015 at Sudan University of Science and Technology, in fish hatchery , Complete randomized block design was used with four treatments,The average body weight of the fry and fingerlings of (Oreochromis niloticus) were 14.7-22 g for big and 10.431-14 for small once at fed and another starved. Data was analysed using analysis of variance (ANOVA), The mean of DO concentrations of integrated were lower than 1 mg/L from 02:00pm to 11:00am between 0.53±0.153 to 0.20± 0.00 at big starved and in big fed, 0.63± 0.115 to 0.13± 0.058 were significantly different between big starve and fed . The Oxygen consumption ranged from 2594.59 to 1000.00 mlO2/m for fingerlings starved for 72 Hrs. The fingerlings were 3490.91ml O2/m to 342.86 ml O2/m when fed commercial dietary to fingerlings. Oxygen consumption rate were significantly different (p0.05) in both sizes and between feeding and starved status during the measurement period compared. The effects of ammonia on carbohydrate metabolism in Nile tilapia (O. niloticus) during the experimental period measured of ammonia in the water were calculated to determining the mean and standard deviation. Analysis of variance revealed that ammonia concentration obtained in big starved fingerlings varied from 1.07±0.06 to 0.73±0.06 and in the big group feeding in range 1.13±0.15 to 0.67±0.07 were no significantly different between big starve and fed. In small fingerlings starved the ammonia obtained from 1.47±0.55 to 1.00 ±0.10, while at the fed group from 1.27±0.25 to 0.83±0.15 . At the end of the study The results showed that there were no significantly at level .
