الفهرس 
Bacterial diversity
MATERIALS AND METHODS TheOnly 14 pages are availabe for public view
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Abstract
River Nile is considered the main source of water in Egypt. In the last decades, River Nile was subjected to different types of pollution. The most important pollution sources were agriculture run-off, domestic and industrial effluents.
Pollution of the environment is reflected by levels of contamination in any aquatic ecosystem, regarding Qarun lake ecosystem many factors including climatic condition, amount of discharged wastewater, seepage from the surrounding cultivated land and geological aspects are expected to change water quality and cause adverse effect in aquatic organisms. Therefore, the following study was conducted.
In the present study, Tilapia fishes were examined bacteriologicaly from River Nile, Qarun lake at different pollution site as well as El-Batts drain to study the bacterial diversity associated with Tilapia in fresh and brackish environment during one year (April 2010- March 2011).
1. Samples collection and identification:
1.1. River Nile water and fish samples:
Water samples were collected from four different sites one of them was selected from the main stream of River Nile (reference point) site (1)N and three other sites located from different point of pollution along Rosetta branch. Those three sites named as: River Nile before mixing with El-Rahawy drain site (2)N, River Nile at the mixed point with El-Rahawy drain site (3)N and River Nile after the mixed point with El-Rahawy drain by 3km (after mixing with wastewater ,agriculture drain such as Menof drain and other individual drain)site (4)N.Tilapia samples were collected from two sites only site (1)N and site (4)N. 1.2. Qarun lake water and fish samples: Water samples were collected from four different sites one of them was collected from El- Batts drain site (1)Q and three other sites located from different point of pollution along Qarun lake. Those three sites named as: Qarun after mixing with El-Batts drain by 3km site (2)Q, Qarun after mixing with El-Batts drain by 10km site (3)Q, and Qarun after mixing with El-Batts drain by 30km site (4)Q. Fish samples were collected from two different pollution sites on El-Fayoum province, fishes were captured from (1)Q while the other fishes were collected from Qarun Lake presented in site (3)Q.
2. Bacteriological examination:
2.1. Determination of total, fecal coliform, E.coli, fecal streptococci, total staphylococci and S.aureus from water and fish samples in River Nile at different pollution sites:
The average MPN Index/100 ml of total and fecal coliform recorded in water samples were (93×103, 24×103), (150×103, 86×103), (1500×105, 950×105) and (11000×105, 4200×105) in sites (1)N, (2)N, (3)N and (4)N, respectively. The average MPN Index/100 ml of E.coli recorded in water were 9.5×103, 28×103, 240×104 and 1100×105 in sites (1)N, (2)N, (3)N and (4)N, respectively. While the average MPN Index/100ml of fecal streptococci recorded in water were 400×102, 21×103, 210×105 and 7.1×107 in sites (1)N, (2)N, (3)N and (4)N, respectively. And the average C.F.U/100ml of total staphylococci recorded in water samples were 180×103, 1100×102, 140×105 and 86×107 in sites (1)N, (2)N, (3)N and (4)N, respectively. The average C.F.U/100ml of Staphylococcus aureus recorded inwater samples were 19×102, 61×102, 62×105 and 48×107 C.F.U/g in sites (1)N, (2)N, (3)N and (4)N, respectively. Where, in fish samples collected from site (1)N, The average value of total and fecal coliform were 33×103, 15×103 MPN Index/g in liver and 30×104, 14×104 MPN Index/g in gills. Density of E.coli, fecal streptococci, total staphylococci and Staphylococcus aureus were not detected in all muscle samples of tilapia fish collected in site (1)N during the whole period of study. While the average values of E.coli were 23×102 MPN Index/g in liver and 48×102 MPN Index/g in gills. And the average values of fecal streptococci were 130×102 in liver and 150×103 in gills MPN Index/g. The average values of total staphylococci and Staphylococcus aureus were 89×102, 39×102 C.F.U /g in liver and 20×103, 8.8×103 C.F.U /g in gills.