Blue Resources for Aquaculture, Environment and Society DevelopmentEgyptian Journal for Aquaculture2090-78779220190601Characterization of probiotic Bacillus subtilis isolated from Nile tilapia (Oreochromis niloticus) digestive tract and evaluation its positive impact on health and immunity.1264645410.21608/eja.2019.13397.1000ENMahmoud MohamedEladawyResearcher, Fish health and management Department , Central Laboratory for Aquaculture Research , EgyptJournal Article20190613In the present study, a probiotic, Bacillus subtilis was isolated from the digestive tract of freshwater Nile tilapia collected from production pounds of the Central Laboratory of Aquaculture Research, Egypt. The isolated strain of Bacillus subtilis was biochemically identified using API 20E and 16S rRNA. The Biosafety. assay confirmed that the isolate was not pathogenic to Nile tilapia fish. Isolated strain was able to survive at increasing concentrations of bile. Isolated strain was sensitive to most used antibiotics. The Isolated strain showed antagonistic activity against bacterial fish pathogens, including Aeromonas hydrophila and pseudomonas aeruginosa. Isolated strain did not show any hemolytic activity against human blood in the blood agar medium. To evaluate the positive impact of the supplementation of an isolated strain of Bacillus subtilis on hematological, biochemical and immunological parameter of Nile tilapia. A total of 120 fish (20 g) were randomly divided into 2 groups (control and treatment with 3 replicates). The control groups were fed the basal diet. Treatment groups were supplemented with B. subtilis 1X109 cfu/g. Results showed that Nile tilapia fed with diets containing B. subtilis for 7 weeks had a significant increase in Hb%, RBCs count, HCT values and WBCs count. Also, there is a significant improvement in liver function test (ALT, AST, Total protein and Albumin). Also, there is a significant increase in immunological parameter (NBT, Lysozyme). Moreover, fish fed with B.subtilis supplemented diets showed improved survival rates after A. hydrophila infection. <br />Keywords:- Bacillus subtilis , Nile tilapia , API 20E, Positive impact.Blue Resources for Aquaculture, Environment and Society DevelopmentEgyptian Journal for Aquaculture2090-78779220190601Combined effect of prebiotics and probiotics on growth performance and feed utilization of Nile tilapia (Oreochromis niloticus)27475378710.21608/eja.2019.16395.1003ENSalhaaMohsenFish production, Animal Production Department, Faculty of Agric. Cairo, Al-Azhar UniversityAhmedElzayatFish production, Animal Production Department, Faculty of Agri. Cairo, Al-Azhar UniversityMohamedEL- NAWSANYFish production, Animal Production Department, Faculty of Agric. Cairo, Al-Azhar UniversityJournal Article20190903. This study aims to investigation of used Bacillus subtilis and combination between Citric acid and Bacillus subtilis in diets of Nile tilapia (O. niloticus) juveniles and affected on Histopathology and morphometric assessment of intestine, growth, feed utilization and body composition. Nile tilapia were fed control diet (D1) without addition, additive Bacillus subtilis (BS) at a rate 10cm/kg diet (D2), 10cm (BS)+5g citric acid/kg diet (D3) and 10cm (BS)+10g (CA)/kg diet (D4) for 90 days. Results showed that morphometric assessment of intestine improved and significant difference in duodenum, jejunum and ileum in mucosal length and villi length between all treatments except mucosal length in duodenum. Also, these results showed the highest values and best group D4 to contain (10cm BS+10g CA) followed by D3 to contain (10cm BS+5g CA) and the lowest values showed in control group (D1). Also, histopathology of intestine showed that duodenum, jejunum and ileum of fish from group control and D2 showing normal villi and normal mucosal lining. On the other hand, results of intestine of fish from group D3 and D4 showing increase the villi length in duodenum, increase the villi length and branches in jejunum and normal mucosal lining in ileum. Results of body weight gain, SGR, condition factor, FCR, FE, PER, PPV and chemical composition of fish showed improvement and significant differences (P≥ 0.05) between all treatments contain citric acid and Bacillus subtilis compared to controlBlue Resources for Aquaculture, Environment and Society DevelopmentEgyptian Journal for Aquaculture2090-78779220190601Antimicrobial activity and immunostimulant effect of fruit by product in cultured fish496616514410.21608/eja.2021.41930.1038ENTaghridNaguibFish health and managment , central laboratory for aquaculture research, agriculture research centerHeba AhmedTolbafish health and managment dept.,central lab for auaclture research.,Agriculture research centerJournal Article20190502This study investigated the effects of dietary orange peels (OP), pommengrate peels (PP) and Banana peels (BP) wasting from juice industry on growth performance, feed utilization and immunity in fish. T1, T2 and T3 had 3% of Orange, Pommengrate and Banana peels respectively, T4 had mixture of 1.5% (OP) and 1.5% (PP), T5 had mixture of 1.5% (OP) and 1.5% (BP), T6 had mixture of 1.5% (OP) and 1.5% (PP), T7 mixture of 1% of each of them and T8 fish fed diet free from any additives (control group). T7 showed significantly high level of weight gain (63.07±1.79 a) and feed efficacy (107.19±2.06a) followed by T1, T4, T5 FER increase respectively 83.86±1.65 c, 80.76±0.95 cd and 90.44±3.98 b than T8 control group (76.16±1.07 d). Similarly, highest values of total proteins, albumin, and globulin were significantly observed in T7 and T1 groups. Likewise, (T7) had a significant increase in lysozyme activity in serum 3.51±0.03a followed by T4 (3.07±0.07b), T1 (3.01±0.07b).T5 (2.73±0.03c) more than control group T8 (1.28±0.03 f). All treated groups had higher level of protection than control group as Treatment 7 showed highest survival rate 90% than control group (60%). Similarly, survival rate in O. niloticus challenged with Saprolegnia spp. were 100% in all groups except treatment 4 had a lower percent 90% more than control group (50%). So the present investigation recommended that use of mixture of 1% (OP), 1% (PP) and 1% (BP) to improve the growth, immunity and tolerance of Nile tilapia to bacterial and fungal infection.Blue Resources for Aquaculture, Environment and Society DevelopmentEgyptian Journal for Aquaculture2090-78779220190701ANALYTICAL STUDY OF THE MARKETING PROBLEMS OF FISH FARMS IN SHARKIA GOVERNORATE679018695810.21608/eja.2020.28379.1022ENAhmed Mohammed DiabElshafeiResearcher, Dept. of Fish Extension and Socioeconomics, Central Laborotry for Aquaculture Research.Journal Article20190625The study aimed to study the current situation of marketing problems of fish farms in Sharkia governorate through: Identifying the motives of the fish farmers toward the fish culture, the relative importance of the sources of marketing information for the farmers, and identifying the degree of the existence of marketing problems among the farmers and the negative impact of the marketing problems from the point of view of the farmers. The important marketing advisory services provided by agricultural extension to solve some of these problems.<br /> This study was conducted on a regular sample of 191 fish farmers in Sharkia governorate (Abbassa-Al-Hussainiyah) in order to achieve the study goals, and the questionnaire was used in the personal interview as a tool to collect data in the period from January to March 2019, The statistical analysis included percentage, mean, display table of frequency, and simple correlation coefficient. The most important results showed the most important motives of the respondents towards fish marketing are increase income (84.29%), and improve the standard of living (83.25%) and the most available sources of information were in wholesalers (3,66), retailers (3,56), friends and neighbors with experience (3,47), and the most common sources of information that respondents were exposed to were: friends and neighbors with experience (3,7), family and relatives (3,56), wholesalers (3,42) and the results also showed that the most important marketing problems facing the respondents, which are related to the lack of marketing knowledge and skills, were the lack of the necessary marketing information (2,51)