Further vstudies on the most common gram - positive bacterial infection in some cultured fish

Gram-positive bacteria cause a disease in fishes and of a considerable importance especially in the recent years. In this investigation a total number of 60 apparently healthy O.niloticus and C.carpio were used for determing the pathogenicety of S.epidermMorphological and biochemical identification of S.epidermids was performed, then application of the RAPD-PCR and SDS PAGE were carried-out in order to detect the heterogenicity within the bacterial isolates. The results showed that there was a heterogenicResults illustrated that, the mortality percent was 10% in O.niloticus when use B.subtilis as a Prophylactic treatment either in water or in diet. The mortality percent was 40%, 90% and 20% in subgroups treated with B.subtilis in water, diet and when use The mortality percent of C.carpio was lower than that of O.niloticus. The mortality rate was 6.7% and zero % when applied B.subtilis as a prophylactic measure in water and diet respectively. Using B.subtilis as a therapeutic agent showed a mortality perceClinically, the infected O.niloticus with S.epidermidis showed severe unilateral and bilateral exophthalmia. The lesion was severe in the tail region beginning as detachment of scales at the peduncle region with emaciation beside stiffness of the caudal pThe use of B.subtilis as a prophylactic measure reduced the severity of the infection, especially when used as a prophylactic agent either in O.niloticus or C.carpio. Slight erythema on caudal fin and shallow ulcer at dorsal muscle. B.subtilis in diet alsTherapeutic effect of B.subtilis did not significantly affect the development of the disease in O.niloticus. In contrast to C.carpio the fish tried to withstand the infection.The results proved that, there was no significant difference in final body weight of experimented O.niloticus groups when compared with control group which fed on basal diet without B.subtilis and there were highly significant increase in body gain percen