الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
The present work was conducted in Central Laboratory For
Aquaculture Research, (CLAR) Abassa, Abu-Hammad, Sharkia, Egypt, to investigate the effect of
addition humic acid (Humabol) with three different protein levels (25, 22.5 and 20 % CP) on water
quality and growth performance of Tilapia (Oreochromis niloticus) and Common Carp (Cyprinus
carpio).
Thirty six concrete ponds of 2 meter as a diameter x 1.2 m as depth, respectively, represents
eighteen treatments (two replicates / each) in three experiments, with a (3.77 m3 total volume)
with 3 fish / m3. The experimental treatments were as follow: Tilapia were fed diets contained
0.2 % Humic acid with 25 or 22.5 or 20 % protein (T1, T2 and T3), respectively, Common carp were
fed diets contained 0.2 % Humic acid with 25 or 22.5 or 20 % protein (T4, T5 and T6), respectively,
represent the first experiment. Tilapia were fed diets without humic acid contained 25 or 22.5 or
20 % protein (T7, T8 and T9), respectively, Common carp were fed diets without humic acid contained
25 or 22.5 or 20 % protein (T10, T11 and T12), respectively, represent the second experiment.
Tilapia and common carp in the same pond were fed diets contained 0.2 % Humic acid with 25 or 22.5
or 20 % protein (T13, T14 and T15), respectively, Tilapia and common carp in the same pond were fed
diets without humic acid contained 25 or 22.5 or 20 % protein (T16, T17 and T18), respectively,
represent the third experiment. The experimental ponds were supplied with well water. Water
exchange rate was 100 % of the
total pond area / 14 days. The first experiment lasted 105 days from the 1
of July to the 15th of October 2013 (T1 to T6), the second and the third experiments lasted 105
days from the 1st of July to the 15th of October 2014 (T7 to T18).
Results showed that there were no significant differences between treatments with and without humic
in temperature degrees, dissolved oxygen, pH, Secchi disk, orthophosphate and chlorophyll (a),
while there were increased in humic acid treatments in NH3, NO3, NO2, total alkalinity and total
hardness.
There were significant differences (P < 0.05) in NO3, NO2, total alkalinity, total hardness and
orthophosphate due to fish species.
Protein level did not effect significantly on temperature, dissolved oxygen, secchi disk, NH3, NO3,
total alkalinity, total hardness and chlorophyll (a). However, pH and NO2 were significantly
increased gradually as the level of protein increased.
Humic acid significantly decreased iron, zinc and cadmium, while it significantly (P < 0.05)
increased in lead, and had no significant effect on manganese and copper.
Fish species had a significant (P < 0.05) effect on iron, zinc, manganese copper, cadmium and lead.
Protein level effect significantly on iron, zinc, copper, cadmium and lead. However, manganese had
no significant effect due to level of protein.
The highest value of chlorophyceae and cyanophyceae (313336 and 11655.5) were observed in humic
acid treatments with significant differences (P < 0.05), while the highest values of
bacillariophyceae and euglenophyceae (1546 and 2328) were detected in treatments without humic
acid.
Fish species had a significant (P < 0.05) effect on phytoplankton during the experiment.
Protein level had significant effect on phytoplankton, 25 % protein level recorded the highest
chlorophyceae (279892), while 20 % protein