الفهرس 
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Abstract
Study On Bacterial and Fungal Diseases Affecting Cage Cultured Sparus Auratus Bacterial diseases are responsible for heavy mortality in both wild and cultured fish and one of the most important factors of economic loss since the beginning of marine fish culture. The prevalence of diseases and the number and types of bacterial pathogens have been well documented in several cultured and wild freshwater fish species, however, only a few bacteriological surveys on the prevalence of bacterial pathogens responsible for outbreaks in marine fishes. Therefore, we have to explore this field to know how we can protect the Egyptian Mari culture against these pathogens. Due to Gilthead Seabream (Sparus aurata L) is a marine fish with high economic value in the aquaculture. Only a few bacteriological surveys have been conducted to the marine fish species diseases out breaks. So, the present work aimed to study the most important bacterial and fungal diseases which infect cage cultured seabream by: 1) Recording the clinical signs and P.M lesions associated with such causative agents of diseases in naturally infected cage-cultured seabream (Sparus aurata L.) native to private fish farms at Wadi-Mariout, Borg El-Arab city at Alexandria governorate. 2) Isolation and identification of the different bacterial and fungal causative agents affecting cage-cultured sea bream. 3) Phenotyping of the isolated bacteria by vitec2 system. 4) Listing the prevalence of the identified bacterial and fungal isolates among the above mentioned diseased fish. 5) Clarify the relationship between identified bacterial and fungal isolates. On the other hand, the Burkholderia mallei, Staphylococcus heamolyticus; Alloiococcus otitis and Shewanella puterfaciens were not isolated from the gills. The highly affected organ followed the gills was spleen where the percentage of isolates were (33.3%, 100% and 100%) inBurkholderia mallei; Staphylococcus heamolyticus and Shewanella puterfaciens respectively. The lowest affected organs are the liver and kidney, where represented by (33.3 % in each organ) in Burkholderia mallei only. Also, the musculature recorded by (50%) in Pseudomonas alcaligenes. The heart was recorded by (25%; 50% and 100%) in Photobacterium damselae; Vibrio alginolyticus and Alloiococcus otitis respectively in cultured sea bream. 1) The incidence of mycological examination of naturally infected seabream cleared that, the most important types of isolated fungi and yeast from cultured seabream (50 fish / 6 organs per fish).The Penicillium spp .,is the most predominant fungi in the examined seabream (36 isolates). The Aspergillus flavus, Candida spp., came in the second rank (12 isolates / each). The Fusarium spp., Legenidium spp., were represented by (9 isolates / each). TheRhodoterulla spp., Rhizopus spp., and Aspergillus fumigatus were also recorded by (6 isolates / each). Concerning Alternaria spp., was in the last rank by (3 isolates). 2) The frequency distribution of different types of isolated fungi and yeasts from cultured seabream (50 fish / 6 organs per fish) indicated that the gills is the target organ for most isolated fungus spp. The predominant isolated funguses were Penicillium spp by (15, 9, 9 and 3 isolates) from the gills, musculature, liver and heart respectively. The Aspergillus flavus was isolated from gills and heart by (9 and 3 isolates) respectively. It worth to be noted that the Fusariumspp., were isolated only from the musculature by (9 isolates). The Rhizopusspp., and Alternariaspp .,were isolated only from the gills by (6 and 3 isolates) respectively. The incidence of Legenidium spp., (6 and 3 from gills and spleen); Rhodoterulla spp .,were represented by(3 isolates from each of heart and spleen), Aspergillus fumigates., were represented by (3 isolates from each of kidney and gills) in cultured sea bream. On the other hand the Candida spp were not isolated from the gills and spleen, while isolated from the liver, heart, kidney and musculature by (3 isolates from each mentioned organs. 3) The percentage of different types of isolated fungi and yeasts from cultured seabream (50 fish / 6 organs per fish).The data was revealed that the percentage of most isolated fungus spp., were recorded in the gills. The predominant percentage isolated funguses were Rhizopus spp., and Alternaria spp., followed by Aspergillus flavus., Legenidium spp., Aspergillus fumigatus and Penicillium spp., by (100%, 100%, 75%, 66.6%, 50% and 41.6%) from the gills respectively. On the other hand, the musculature recorded by (25%, 25% and 100%) in Penicillium spp; Candida spp and Fusarium spp respectively .The liver was recorded by (25%) only in both Penicillium spp and Candida spp .The highly affected organ followed the gills was heart where the percentage of isolates were (8.3%, 25%, 25% and 50%) in Penicillium spp; Aspergillus flavus; Candida spp and Rhodoterulla spp respectively. It worthy to be note that the lowest affected organ was spleen and represented by (33.3% and 50%) in Legenidium spp and Rhodoterulla spp respectively. Finally, the kidney was documented by (25% and 50%) in Aspergillus fumigatus and Candida spp respectively in cultured sea bream. 4) Relation between identified bacterial and fungal isolates : On the other hand Penicillium appear four times associated with Rhodoterulla and vibrio alginolyticus together . While appear tow times associated with Rhizopus and Burkholdria cepcaia together from the previous we found that there is a strong relationship between the isolates of vibrio alginolyticus and Rhodoterulla which they founded to gather six times four of them associated with penicillium and tow associated with Aspergillus flavus . Also there is relationship between Burkholderia cepcaia and Rhizopus which founded together three times one of them with Rhizopus alone and the others with both Rhizopus and penicillium together. On the other hand we found that there is a strong relationship between the isolates of shewanella puterfaciens, penicillium and Aspergillus flavus. All isolates of shewanella were associated with both penicillium and Aspergillus flavus together.