Chronic effect after acute exposure to commercial petroleum fuels on physiological status of Nile tilapia, Oreochromis niloticus (L.)

Abstract

This study was conducted to explore the effect of kerosene, gasoline, or diesel, on the health status of Nile tilapia, Oreochromis niloticus (L.). Healthy fish (49.5 ± 1.3 g) were exposed to 0.01% (v/v) CPFs in glass aquaria for 5 min and then returned to clean freshwater for 4 weeks. Signs of poisoning in intoxicated fish were air gulping, increased opercular movement, loss of balance, and dyspnea. At the end of this experiment, fish were collected, counted, and weighed. Fish in the control group grew gradually up to the end of the experiment; their growth was better than those exposed to any of CPFs. Moreover, weight gain, specific growth rate, feed intake, feed conversion ratio, and survival rate of the exposed fish were poor when compared to the control fish group. The physiological variables including red blood cells (RBCs) and hemoglobin content in fish exposed to CPFs changed by time. The maximum count of RBCs was obtained at the 1st week, and decreased gradually to the 4th week. The glucose and cortisol levels were maximized after the exposure to kerosene, diesel or gasoline and decreased gradually to the end of the experiment. Plasma lipid, protein, aspartate aminotransferase, and alanine aminotransferase in the exposed fish were significantly altered by CPF exposure. They were gradually close to the control values after 3 to 4 weeks of recovery. This study concluded that the acute exposure to CPFs significantly reduced the growth performance of Nile tilapia and significantly affected its physiological status, which may be recovered after awhile.