Some hematological and biochemical changes in tilapia, oreochromis niloticus and tilapia zillii exposed to mixture of copper and lead

Abstract EN

A hematological and biochemical study was conducted on the freshwater fish Oreochromis niloticus and Tilapia zillii.

The fish were acclimated to laboratory conditions for two weeks before use.

Then the fish were exposed for 12 weeks to a mixture of copper and lead at a ratio 1:1 of the LC50 of both metals.

Hematological and biochemical analyses were carried out every two weeks during the exposure period.

Results indicted the following : In the hematological study, there was a significant increase in the total erythrocytes count (RBCs), as well as the hematocrite (Ht) and mean corpuscular hemoglobin concentration (MCHC) in O.

niloticus upon exposure to the heavy metals mixture .This increase was observed after 10 weeks for RBCs count, from the 6th week of exposure till the end of the experiment for Ht and throughout the whole time of exposure for MCHC.

For T.

zillii, the increase in the RBCs count was noticed at weeks 4,6 and 12; the increase in Ht occurred at weeks 10 and 12 ; while a decrease in MCHC was noticed during the entire period of exposure.

On the other hand, hemoglobin content (Hb) decreased significantly starting from the second week of exposure till the end of the experiment for O.

niloticus.

Similar decrease was noticed for T.

zillii (except the value at 8 weeks of exposure) and continued till the end of the exposure period.

Non-significant changes were observed in the serum glucose concentration for O.niloticus, while serum glucose was significantly increased in metals treated T.

zillii.

For both species, non-significant changes were noticed in Liver and muscle's glycogen levels.

However, serum protein levels were significantly increased in O.

niloticus, but changes were non-significant in T.

zillii.

On the other hand, muscle total protein showed a significant decrease after 10 weeks of exposure in O.

niloticus.

Such significant decrease in muscle total protein of T.

zillii appeared only during the 12th week of exposure.

Changes in serum cretonne and uric acid levels in O.niloticus starting from the 8th week of exposure till the end of the experiment.