Gyamfi Stephen
PROJECT UPDATE
Experiment 1: WATER QUALITY DYNAMICS IN EARTHEN PONDS WITH AND WITHOUT FISH- completed
This study assessed the water quality dynamics in earthen ponds with and without fish over three months. Two ponds (10m*15m* 1m) were stocked with all male tilapia while the other two were without fish. Sampling for water quality in Photos 1 & 2 using the Hach multi-parameter probe, fish sampling (Photo 3) at the end of the experiment. While in Photo 4, nutrients (nitrate, nitrites, and ortho-p) were analyzed at the laboratory to help with diet formulation, KNUST, Kumasi, Ghana.
Experiment 2: EFFECT OF AMMONIA ON CARDIOVASCULAR RESPONSE, VENTILATION FREQUENCY AND OXYGEN CONSUMPTION IN NILE TILAPIA (Oreochromis niloticus) - completed
The effects of unionized ammonia (UIA) on the resting oxygen consumption (MO2) and associated changes in ventilation frequency (fV) and heart rate (HR) in Nile tilapia (O. niloticus) were examined. In a series of experiments, Nile tilapia were exposed to different levels of UIA, either acutely (1h) or prolonged (24h) by injecting pre-determined ammonium chloride (NH4Cl) stock solution into the experimental water. For acute exposures, UIA concentrations were increased stepwise from 0 (control) to 0.097 mM at hourly intervals. During prolonged exposure, fish were exposed to 0.007 mM- UIA for 24h. It is evident from this study that Nile tilapia is tolerant to low UIA ≤ 0.061 for acute exposure but respond more to prolonged UIA exposures even at low concentration.
- Fish connected with electrodes on an operating table (B) measuring heart rate at each UIA exposure
Experiment 3: COPING MECHANISM OF NILE TILAPIA TO HIGH ENVIRONMENTAL AMMONIA(HEA)- on going
Physiological strategies by Nile tilapia to adapt to high environmental ammonia was monitored when fish was exposed to different levels of unionized ammonia ( 0.007mM and 0.061mM-UIA) for a period of 1,3 and 7 days. This was achieved by examining the fish gills, hematological parameters and determining levels of glutamine and urea production as a detoxification mechanism by the fish in the muscle and the kidney.
