الفهرس 
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Abstract
Pollution with metals is one of the disadvantages of the industrial development. Lead toxicity, in
particular, is of major importance because of its cumulative toxic effects as well as lasting in
animal tissues.
A lot of literature has accumulated on the effects of lead toxicity in laboratory-controlled
animals as well as in hazardous environmental exposure to the metal
As one of the aspects of the effect of the lead toxicity on the body, the present work studies the
effect of lead on lipid profiles and some enzymatic activities.
Eighty Catfish Clarias lazera were brought to the laboratory and assigned into 4 groups according
to the amount of lead acetate dissolved in the rearing water as follows:
1) group 1: Included twenty healthy fish they were kept in glass container 100-L water and it was
considered as a control group.
2) group 2: Comprised twenty healthy fish they were kept in glass container 100 L water in which
the lead acetate were added in the water at a dose.of 5 ppm/L.
3) group 3: Included twenty healthy fish they were kept in glass container 100 L water in which the
lead acetate were added in the water at a dose of 10 ppm/L.
4) group 4: Comprised twenty healthy fish they were kept in glass container 100 L water in which
the lead acetate were added in the water at a dose of 20 ppm/L.
Fish in all groups were fed with fish formulated ration every day. Water was changed daily and the
fresh lead acetate solution was added
·,,,·,
daily in the dose described above.
Fish were kept in glass bonds for the whole experimental duration (eight weeks). Regular cleaning
of the bonds as well as food supplementation were undertaken daily.
By the end of every two weeks, fish were sampled for biochemical investigations. Mortality was
negligible in all groups.
The collected blood samples were centrifuged for separation of clear non-hemolyzed sera. The
,,collected sera were subjected to the following biochemical determination of:
1- Serum total lipids.
2- Serum total cholesterol. 3- Serum HDL cholesterol. 4- Serum LDL cholesterol. 5- Serum
Triglycerides.
6- Glutathione-S-Trartsferase activity.
7- Cholinesterase activity.
8- Lipase activity.
9- MDA level.
Liver and muscle tissues were also collected from control and experimental groups and
subjected to determination of lead residue.
The present study reveled that:
1: There were a very highly significant increase (p > 0.001) in serum total cholesterol, serum
total lipids, sennn triglycerides and LDL-cholesterol following exposure of catfish ( Clarias
lazera) to lead intoxication in different concentrations of lead acetate at the 2nd, 4th’ 6th and
gth week post experiment respectively.
2: There were a vey highly significant decrease (p 0.001) in serum HDL-cholesterol following
exposure of catfish ( Clarias lazera) to the different concentrations of lead acetate at the 2nd,
4th, 6th and gth week post experiment respectively. 3: There were a very highly significant decrease (p 0.001) in serum
glutathione-S-transferase and serum lipase activities in all treated groups at the corresponding
time intervals.
4: There were a very highly significant increase (p 0.001) in the mean values of cholinestrase
activity as a result of lead intoxication throughout the experimental period.
5: There were a very highly significant increase in the mean values of lead in serum, muscle and
liver tissues as a result of lead intoxication throughout the experimental period.
It could be concluded that lead intoxication disturb lipid profile and enzymatic activities.’ Thus
significant biochemical changes relating to the levels of fat and fat components induced by lead
may be more hazardous and may reduce fecundity as lipids play an important role in catfish (
Clarias lazera) reproduction as an energy source and a precursor of steroids.