The Effects of Dietary Amino-acid L-cysteine on Blood Parameters of Grey Mullet (Mugil cephalus L.), Exposed to Heavy Metals Cu and Zn

This study aimed to investigate the effects of dietary amino-acid L-cysteine on the blood parameters of grey mullet (Mugil cephalus L.), exposed to heavy metals copper and zinc. The required juvenile grey mullets with an average weight of 27.4±3 g were captured from coastal waters of Chabahar Bay. The experimental fishes were exposed to heavy metals Cu and Zn and fed with three diets containing 25, 50 and 100 percentage of cysteine relative to the cysteine content of the basal diet for 45 days. Blood samples were taken from all treatments at three intervals of 4, 22 and 45 days after the onset of the experiment, and hematologic parameters including red blood cell count, hemoglobin and hematocrit and RBC indices of MCV, MCH, and MCHC were measured. Statistical analysis of data collected from the blood parameters showed that heavy metals Cu and Zn combined with different concentrations of cysteine had significant effects ​​(P<0.05) on the amount of red blood cells, hemoglobin, and hematocrit, MCHC, MCH and MCV.These factors had a significant increase in short term (4 days) compared to the control group, and showed a decreasing trend afterwards as the time progressed. The results of this investigation proved that the amnio acid systein does not affect the hematologic factors of grey mullet, and the observed variations in the studied factors were due to the exposure to heavy metals. Overall this research showed that the hematologic factors of this fish can be used as an appropriate biomarker in determination of heavy metals Cu and Zn in water resources.