This study assessed the impact of dietary supplementation of single-and multi-strain Bacillus-based probiotics on growth performance, intestinal morphometry, blood parameters, immune-oxidative status and transcriptomic response of Nile tilapia for 60 days. Fish (N = 150, 1.632 ± 0.035 g) were allocated into five experimental groups:(1) Control group (CG) that was fed on a basal diet; (2) Eco. 0.01%, received basal diet with 0.1 g/kg Ecobiol; (3) Eco. 0.02%, received basal diet with 0.2 g/kg Ecobiol;(4) Pro-F FMC 0.001%, received basal diet with 0.001 g/kg Sanolife PRO-F FMC; (5) Pro-F FMC 0.002%, received basal diet with 0.002 g/kg Pro-F-FMC. Fish received Pro-F FMC 0.002% displayed higher growth performance than CG (p < 0.05), while Pro-F FMC 0.001% exhibited the highest intestinal weight. Sanolife PRO-F FMC supplementation improved intestinal villi length and goblet cell number while decreased inter-villi space (p < 0.05). The best haemoglobin, haematocrit and monocyte per cent were observed in Pro-F FMC 0.001%, whereas Pro-F FMC 0.002% revealed the best leukocyte, lymphocyte and neutrophil contents. Pro-F FMC-supplemented groups showed better phagocytic activity, phagocytic index and lysozyme activity than Ecobiol-supplemented groups and CG. Pro-F FMC 0.001% enrichment induced the highest upregulation level of NPYα, AgRp-2, ghrelin and GH-1, whereas Pro-F FMC 0.002% significantly upregulated IGF-1 and IGF-2 gene expression. Eco. 0.02% induced the highest upregulation level of orexin and galanin gene expression.Conclusively, dietary enrichment with single-or multi-strain Bacillus-based probiotics is likely to improve growth, immunological parameters and transcriptomic response of Nile tilapia.
Objective: This study was aimed to survey Aeromonas spp associated with cultured Nile tilapia Oreochromis niloticus (O. niloticus) showing signs of motile Aeromonas septicemia (MAS) at different fish farms; molecular characterization and identification of test isolates; and to test the isolates for their antimicrobial and virulence activities that contribute to its pathogenesis.
Design: Observational study
Animals: 280 Nile tilapia
Procedures: Clinically diseased 280 Nile tilapia, were collected from different localities at Kafr El-Sheik and Dakahlia governorates. The clinical picture and gross lesions were recorded. Aeromonas spp were isolated and presumptively identified using API20E. The identification was confirmed using PCR. Hemolysin (hylA), lipase, and aerolysin (aerA) virulence genes were detected among isolates obtained from different sampling sites. Besides, antimicrobial activity was reported for the identified A. hydrophila.
Results: General septicemic signs were evident on Nile tilapia including, skin hemorrhages and ulcerations, bilateral exophthalmia, congested internal organs with significant mortalities. The prevalence of bacterial infection among naturally diseased Nile tilapia was 79.17, 70, and 58.33 in Kafr El-Sheikh, El- Manzala, and Gamsa fish farms, respectively. The most prevalent bacterial isolates were aeromonads (29.84 %), of all, 65.63 A. hydrophila, 18.75 A. caviae, and 15.63 A. sobria. All isolates were positively amplified using a species-specifying primer to determine A. hydrophila. Virulence genes detection revealed that five A. hydrophila isolates (83.3 %) harbored the aerA gene. Meanwhile, hylA and lipase genes positive isolates were lower reaching 16.7 % for both genes. A. hydrophila was highly sensitive to ciprofloxacin, amikacin, trimethoprim, and chloramphenicol, and MAR index of A. hydrophila isolates was ranged from 0.16-0.42
Conclusion and clinical relevance: Our findings demonstrate that Aeromonas spp are among the bacterial pathogens implicated in summer mortalities in tilapia fish farms in Egypt. Besides, determination of the prevalence, virulence genes, and antibiotic resistance pattern associated with the disease outbreaks is critical data that warrant the development of strategies to proper monitoring and farm management practices.
Amyloodinium ocellatum, adinoflagellate which causes one of the most serious diseases of warm water marine aquaculture. The parasite produces a powdery or velvety appearance on infected fish, and the resulting disease is commonly referred to as "marine velvet," velvet disease, or Amyloodiniosis. The organism is a dinoflagellate ectoparasite and has been reported in a wide range of marine and estuarine fish. It is one of a very few organisms that can infect both teleosts and elasmobranchs (Alvarez-Pellitero, 2008). This makes it a concern for public aquaria. This ectoparasite can be found on gills and skin (body and fins) of host fish. It can cause devastating disease and mortality because the organism is able to reproduce quickly when fish are crowded, especially in closed systems. This parasite has a broad host and geographic range, causing fish mortalities in tropical and temperate environments. Rapid spread of the parasite and high mortality are common in cultured fish if the organism is not recognized and treated early in the course of an outbreak. One of the most important of the ectoparasitic protozoaisIn this respect, the present study was aimed to investigate the occurrence of Amyloodiniosis among cultured European seabass (Dicentrarchus labrax L.; Moronidae; Perciformes) fishes. This work was carried out on 1065 European seabass fishes of diffrerent life stages (546 fry-222 fingerling and 78 adults) which were collected in different seasons of the year. Cultured fish were collected from different marine farms in Egypt during the period from April 2015 to April 2016 and subjected to full clinical parasitological and histopathological examination studying the environmental stressors surrounding examined fish and their association with A.ocellatum infestation Study the ecological factors affects Amyloodiniosis. As well as examining the antiseptic activity of hydrogen peroxide against the ectoparasitic protozoan A.ocellatum as a trial for treatment.
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