الفهرس 
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Abstract
In recent time, increasing fish production is very important to face
the problem of protein deficiency. Fresh water fishes provide a major
source of protein.
According to FAO., Fishes Esstatistics (1992), the total yeild of
Ti/apia (Oreochromis) in 1990 was 6.6 million metric tons, Egypt
contribute about 250.000 metric tons.
Tilapia species is widely distributed in our fresh water specially in
River Nile, Lakes and irrigation canals.
Pseudomonas aeruginosa as well as Ps. jluoresences are the major
problems in aquaculture and cause bacterial hemorrhagic septicemia, that
causes up to 90%,mortalities in population of fish. In the present study, an
attempt was made to evaluate the effect of some natural products on the
sensitivity of the isolated bacteria infected fishes and on some bacterial
characteristics. The results obtained can be summarized as follows:
1- Clinical examination of the naturally infected fishes indicate the
presence of hemorrhage on several parts of body surface (mouth, base
of fins , abdomen, opercula and around the annal opening) , this is in
addition to turbidity of the eyes and slight exophthalmia , roughness of
the scales and sometimes scale losses.
2- The postmortem examination of the naturally infected fishes indicate
the presence of congestion of the gills, hepatomegaly, splenomegaly,
Summary 119
distended gall bladder with bile, congestion in kidney, congestion
hemorrhage in intestine and accumulation of bloody fluides in
abdominal wall .
3- Bacterialogical examination of the infected fishes revealed the presence
of four types of bacteria. Dependant on morphological, physiological
and biochemical characterestics and by applying the AP120E system,
the isolated bacteria were identified as Ps.aeurginosa ,Ps.fluoresences,
Salmonella arizonae and Citrobacter baraakii .
4· The two pathogenic Pseudomonas species were isolated from skin, liver,
kindeny, spleen, intestine, gills and ascetic fluides, mean while the two
non pathogenic species namely Salmonella arizonae and Citrobacter
baraakii were isolated only from intestine, gills and skin .
5- Extraction of the dried parts of Origanum vulgare and the rhizomes of
Zingiber officinale with water as well as selective organic solvents was
carried out .
6- Preliminary antibacterial screening of each of the obtained extract as
well as industerial chemical antibiotices against the isolated bacteria
showed differences in the mean diameter of the inhibition zones.
Ps.aeurginosa, attained the highest mean diameter of the inhibition zone
followed by Ps. fluoresences, Salmonella arizonae and Citrobacter
baraakii being, 35,25 & 35,25 & 30,18 & 25,16 for Origanum
vulgare and Zingiber officinale respectively.
Summary 120
7· Two crystalline compounds were isolated from the aerial parts of
Origanum vulgare and rhizomes of Zingiber officinale. The microanalysis
of the two compounds as well as UV, IR, NMR and Mass
spectrum revealed that each of the obtained compound consists of C,H
and oxygen with molecular formula CII HIB 09 and e21 ~5 06 for the
compound separated from Origanum vulgare and Zingiber officinale
respectively.
8- Antibacterial sensitivity as well as minimum inhibatory concentrational
(MIC) of the two compounds as compared with chloromphenecol were
determined . The results inducate that the compound isolated from
Origanum vulgare has the same MIC , value as chloromphenecol ,
while the compound separated from Zingiber officinale has a relatively
higher MIC value and lower mean diameter of inhibition zones than the
former indicating that the compound isolated from Origanum vulgare
is more effective as an antibacterial agent than that of Zingiber
officina/e.