ROLE OF HEAVY METALS BIOACCUMULATION ON SOME PHYSIOLOGICAL AND HISTOPATHOLOGICAL CHANGES IN THE CULTURED OREOCHROMIS NILOTICUS AND MUGIL CEPHALUS AT EL-FAYOUM GOVERNORATE, EGYPT

Abstract

As the world population increase, the demand for high protein foods would gradually rise. Heavy metals are natural trace components of the aquatic environment, but their levels have been increased due to industrial wastes, geochemical structure, agricultural and mining activities. The absorption and accumulation of different pollutants vary among different biological systems. Therefore, the present study aims to high lighten the impact of the bioaccumulation of heavy metals in different organs of fish and the factors affecting their dissemination. It is also concerned with the study of some physiological and biochemical parameters of the two studied fish species and their ability to resist stressors. This is confirmed by histopathological investigation on the diagnosis of fish diseases caused by the heavy metals. Bioaccumulation of heavy metals in fish tissues led to histopathological alterations in liver and kidneys of both fish species collected from the studied fish farms that irrigated with agricultural drainage water (El-Berka and El-Wadi).These alterations didn’t occur in case of Demo fish farm that irrigated with fresh water of Bahr Yousef (branch of the river Nile). Data representing the hematological parameters of both fish species collected from Demo fish farm showed blood picture values within normal ranges. However, there was a highly significant decrease in values of erythrocytes count, hemoglobin content and hematocrit value for both studied fish species collected from the other studied fish farms (El-Berka and El-Wadi). This decrease was accompanied by an increase in mean corpuscular volume as a case of macrocytic anemia in case of Oreochromis niloticus and microcytic anemia in case of Mugil cephalus. The present results revealed that there were highly significant differences in the other blood indices and blood leucocytes of each species individually collected from the different studied fish farms. The results declared highly significant differences in serum glucose, total protein, creatinine, and uric acid concentrations, in addition to ASAT and ALAT activities for each species in the studied fish farms that resemble different aquatic habitats.