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Although fish are a valuable source of animal protein for human, their production is reduced sometimes by parasitic diseases. The purpose of this study was to ascertain the frequency and importance of possible parasites that could infect freshwater fish in Sohag governorate. A total of 150 samples [100 Nile tilapia (Oreochromis niloticus) and 50 catfish (Clarias gariepinus)] were chosen at random from various farms in the Sohag Governorate for this purpose. According to the parasitological analysis of the collected fish, Clarias gariepinus had the highest infection rate 64% (32/50) compared to Oreochromis niloticus 56% (56 / 100). Quadriacanthus spp. (50%), Contracecum spp. (50%), Trichodina spp. (56%), Myxobolus spp. (55%), Cryptosporidium spp. (50%), and encysted metacercaria [microscopic (55%), and macroscopic (35%)] were the parasites found in Nile tilapia fish. In contrast, the identified parasites in catfish included microscopic encysted metacercaria (60%) and Quadriacanthus spp. (54%), Trichodina spp. (64%), Myxobolus spp. (44%), Henneguya spp. (40%), and Cryptosporidium spp. (56%). It is evident from the current study that a significant frequency of numerous zoonotic parasites were found in the fish under examination. As a result, control measures in fish farms are required to prevent the spread of these parasites, which pose a risk to public health. [ABSTRACT FROM AUTHOR]

Introduction: Candida albicans (C. albicans) can form biofilms; a critical virulence factor that provides effective protection from commercial antifungals and contributes to public health issues. The development of new antifungal therapies, particularly those targeting biofilms, is imperative. Thus, this study was conducted to investigate the antifungal and antibiofilm effects of Lactobacillus salivarius (L. salivarius), zinc nanoparticles (ZnNPs) and nanocomposites (ZnNCs) on C. albicans isolates from Nile tilapia, fish wash water and human fish sellers in Sharkia Governorate, Egypt. Methods: A cross-sectional study collected 300 samples from tilapia, fish wash water, and fish sellers (100 each). Probiotic L. salivarius was immobilized with ZnNPs to synthesize ZnNCs. The study assessed the antifungal and antibiofilm activities of ZnNPs, L. salivarius, and ZnNCs compared to amphotericin (AMB). Results: Candida spp. were detected in 38 samples, which included C. albicans (42.1%), C. glabrata (26.3%), C. krusei (21.1%), and C. parapsilosis (10.5%). A total of 62.5% of the isolates were resistant to at least one antifungal agent, with the highest resistance to nystatin (62.5%). However, 75% of the isolates were highly susceptible to AMB. All C. albicans isolates exhibited biofilm-forming capabilities, with 4 (25%) isolates showing strong biofilm formation. At least one virulenceassociated gene (RAS1, HWP1, ALS3, or SAP4) was identified among the C. albicans isolates. Probiotics L. salivarius, ZnNPs, and ZnNCs displayed antibiofilm and antifungal effects against C. albicans, with ZnNCs showing significantly higher inhibitory activity. ZnNCs, with a minimum inhibitory concentration (MIC) of 10 µg/mL, completely reduced C. albicans biofilm gene expression. Additionally, scanning electron microscopy images of C. albicans biofilms treated with ZnNCs revealed asymmetric, wrinkled surfaces, cell deformations, and reduced cell numbers. Conclusion: This study identified virulent, resistant C. albicans isolates with strong biofilm-forming abilities in tilapia, water, and humans, that pose significant risks to public health and food safety. [ABSTRACT FROM AUTHOR]

The present study aims to evaluate the potential effects of cyanobacteria on water quality parameters and Oreochromis niloticus in the fish ponds at Al-Abbassa Fish Hatchery, Sharkia Governorate, Egypt. The study identified five cyanobacterial genera: namely, Anabaena, Gleotrichia, Lyngbya, Oscillatoria and Phormidium. Oscillatoria sp. was the dominant genus in the selected fish ponds. Physico-chemical parameters of water samples showed significant variations during the four seasons. Anabaena sp. extract had the most toxic effect on the survival rate of O. niloticus after 72 h of exposure. Biochemical parameters of collected O. niloticus fish significantly increased compared to the control group. We concluded that the detected cyanobacterial genera in the fish ponds affected water quality and O. niloticus fish. [ABSTRACT FROM AUTHOR]

Objective: During Egypt's hot summer season, Aeromonas veronii infection causes catastrophic mortality on Nile Tilapia Oreochromis niloticus farms. Egypt is ranked first in aquaculture production in Africa, sixth in aquaculture production worldwide, and third in global tilapia production. This study aimed to investigate, at the molecular level, the early innate immune responses of Nile Tilapia to experimental A. veronii infection. Methods: The relative gene expression, co‐expression clustering, and correlation of four selected immune genes were studied by quantitative real‐time polymerase chain reaction in four organs (spleen, liver, gills, and intestine) for up to 72 h after a waterborne A. veronii challenge. The four genes studied were nucleotide‐binding oligomerization domain 1 (NOD1), lipopolysaccharide‐binding protein (LBP), natural killer‐lysin (NKL), and interleukin‐1 beta (IL‐1β). Result: The four genes showed significant transcriptional upregulation in response to infection. At 72 h postchallenge, the highest NOD1 and IL‐1β expression levels were recorded in the spleen, whereas the highest LBP and NKL expression levels were found in the gills. Pairwise distances of the data points and the hierarchical relationship showed that NOD1 clustered with IL‐1β, whereas LBP clustered with NKL; both genes within each cluster showed a significant positive expression correlation. Tissue clustering indicated that the responses of only the gill and intestine exhibited a significant positive correlation. Conclusion: The results suggest that NOD1, LBP, NKL, and IL‐1β genes play pivotal roles in the early innate immune response of Nile Tilapia to A. veronii infection, and the postinfection expression profile trends of these genes imply tissue‐/organ‐specific responses and synchronized co‐regulation. Impact statementWe tracked the early responses of four innate immunity genes (NOD1, LBP, NKL, and IL‐1β) in the spleen, liver, gills, and intestine of Nile Tilapia for up to 72 h after infection with Aeromonas veronii. The gene expression trends and the specific tissue/organ responses revealed a dynamic and coordinated co‐regulation. These findings provide valuable preliminary insights into the intricate immune mechanisms underlying the response of Nile Tilapia to A. veronii infection and may extend to other similar gram‐negative bacterial pathogens. [ABSTRACT FROM AUTHOR]

One of the key challenges in aquaculture is the selection of individuals with superior traits, including rapid growth rate, high flesh quality, and disease resistance. Marker-assisted selection (MAS) using molecular markers (e.g., simple sequence repeats; SSR) is known to be more effective in identifying individuals with specific traits based on their genetic makeup. The current study aimed to examine SSR markers across different linkage groups in their efficiency in characterizing the Nile tilapia fish with superior growth performance traits for usage as effective tools for MAS. A total of 152 Nile tilapia samples with identical ages but contrasting growth performances were collected from a fish farm in Kafr El-Sheik Governorate, Egypt. The collected genotypes were evaluated for growth performance metrics such as weight and length, and their microsatellite allelic patterns were also analyzed. A total of 13 microsatellite markers were assessed in the two sampled Nile tilapia categories. The t-test of growth performance traits between the two fish categories revealed highly significant differences in body weight and length. The average number of alleles per locus in the large and small populations was 2.6 and 2.2, respectively. The analyzed populations showed a significant deviation from Hardy-Weinberg equilibrium.Only seven markers showed private alleles unique to either small or large populations, indicating the suitability of these markers for association genetic studies. The studied markers showed low to moderate gene diversity (H), which ranged between 0.25 and 0.48, with an average of 0.41. The discrimination power of the studied loci was relatively high (D = 0.888). The discrepancies in growth parameters between the investigated populations were aligned with the disparities in allele frequency, indicating a possible correlation between certain allele(s) and growth performance characteristics. The present study highlighted the effectiveness of specific SSRs in addressing growth parameters during the planning for the Nile tilapia selection in breeding programs. [ABSTRACT FROM AUTHOR]

Reproduction is among the most vital biological processes in the life cycle of any organism, such as fish. The biology of Oreochromis niloticus reproduction in Lake Nasser and Lake Nubia was studied using different mesh sizes of gill nets. A total of 480 Oreochromis niloticus were caught from Lake Nasser, Egypt, and 369 from Lake Nubia, Sudan, from January through December 2021. Sex ratio size at first maturity and maturity stages of O. niloticus were examined. In Nasser's Lake, the sex ratio of male to female was 1:1.02, whereas in Lake Nubia, it was 1:0.89. The first maturity length in Lake Nasser was 27.5cm for males and 27cm for females, while in Lake Nubia, it was 32cm for males and 26cm for females. The gonado somatic index indicated that the species breeds in Lake Nasser and Nubia during summer and spring, respectively. [ABSTRACT FROM AUTHOR]

This study assessed the marketing efficiency of two crucial fish species in Egypt, the Nile tilapia (Balti) and mullet (Bouri), contributing 73.4% to the nation's total fish production. Utilizing data envelopment analysis (DEA) and the variable returns to scale model, marketing efficiency for the Nile tilapia ranged from approximately 62.4 to 100%, with an average of 87.5%, while mullet fish exhibited a range of 36.2 to 100%, averaging 83.4%. The findings suggest a marketing efficiency deficit of 12.5% for the Nile tilapia and 16.6% for mullet fish, attributable to factors not considered in the model. To enhance efficiency, increasing marketing margins or fish production is recommended. Scale efficiency analysis revealed that some fishers failed to achieve an optimal production efficiency. The Nile tilapia could increase productivity by 24.1%, through optimization at the minimum point on the average total cost curve (MC = AC). Similarly, mullet fish could increase productivity by 27.4%, using the same approach. Furthermore, 70% of the Nile tilapia volume demonstrated increasing returns to scale (IRS), while 25% exhibited decreasing returns to scale (DRS). For mullet, 80% demonstrated IRS, and 10% exhibited DRS. Identified marketing challenges included high summer temperatures causing significant losses, financial constraints, insufficient liquidity, high labor costs, lack of marketing information, and elevated taxes. Recommendations include providing comprehensive marketing information, ensuring well-equipped transportation, attempting to enhance liquidity through lending, and supporting energy to reduce costs for fishing-related activities. [ABSTRACT FROM AUTHOR]

In Egypt, the temperature of the water fluctuates drastically, reaching a daytime high of 25 °C and a nighttime low of 15 °C, respectively, in the spring and the fall. To understand the mechanism behind fish kill in fish farms, an indoor experiment was conducted wherein 240 Nile tilapia weighing 24 ± 2.5 g were stocked in 12 glass aquaria (20 fish/aquarium). Water temperature was regulated throughout the day at 27 ± 1.5 °C for 12 h from 8:00 a.m. to 8:00 p.m. and at 18 ± 1.5 °C for the remaining 12 h. Fish samples (mucus and tissues) were collected four times with a week interval. Proinflammatory tumor necrosis factor-α and interleukin (IL)-1β were decreased during the 4 weeks, while anti-inflammatory IL-10 was highly upregulated during the first week and then decreased compared to the control. Heat shock protein-70 was significantly raised, but IL-8 was unaffected. The gene expressions of antioxidant enzymes catalase and glutathione peroxidase were markedly elevated in the first week and then decreased linearly until they no longer differed from the control group. Mucus lysozyme significantly decreased in weeks 1 and 2 and then began to increase in weeks 3 and 4. Every week, Aeromonas hydrophila infection resulted in clinical signs that were delayed by over 2 days compared to the control group. The mortality rate increased from 35 to 40%, and bacteria were isolated at a rate of 61.54 to 75% from the surviving fish, compared to a rate of 41.67% in the control group. Fluctuations in water temperature suppress the immunity of Nile tilapia, making them vulnerable to bacterial infection. [ABSTRACT FROM AUTHOR]

Vibrio alginolyticus and Streptococcus agalactiae are important bacterial pathogens that yielded high losses in Nile tilapia in Egypt. The present study aimed to check the protective efficacy of inactivated whole-cell bivalent vaccines against these pathogens using incomplete Freund's adjuvant and Montanide™ IMS 1312 VG as adjuvants. The antibody titers have been determined at different weeks post-vaccination (WPV). Moreover, the protection levels against the challenged bacterial pathogens have also been examined in relation to the time-dependent protection at different WPV. The results revealed that serum antibodies were generated in all immunized fish at 1st WPV, peaked at 4th WPV, continued, and gradually decreased from 6th WPV to 14th WPV in all vaccinated groups. In addition, vaccines induced significantly higher protection of the immunized tilapia, manifested by higher survival rates. We noticed that the antibody levels and survival rates of the vaccinated fish by a vaccine adjuvanted by Montanide™ IMS 1312 VG were higher than those produced by a vaccine adjuvanted by incomplete Freund's adjuvant at different time points. Moreover, no external clinical signs, visceral adhesions, or internal lesions were recorded in the vaccinated tilapia, demonstrating the safety of the formulated vaccines. According to the aforementioned findings, we could suggest that the prepared bivalent vaccines, using the two adjuvant types, are safe and highly protective and could be utilized as promising candidate vaccines to increase the resistance of Nile tilapia against V. alginolyticus and S. agalactiae infections. Moreover, Montanide™ IMS 1312 VG enhanced the immuno-protectivity and exhibited optimum immune response and earlier protection compared to the vaccine adjuvanted by incomplete Freund's adjuvant, demonstrating its added value during the preparation of tilapia vaccines. [ABSTRACT FROM AUTHOR]

Nile tilapia aquaculture is a fast-growing industrial sector in Egypt. However, the progress of this industry is hindered by many challenges as poor water quality and associated bacterial infections. Aeromonas hydrophila is an important zoonotic waterborne aquatic pathogen responsible for severe outbreaks in tilapia culture so the current study aimed to investigate the prevalence of Aeromonas hydrophila in tilapia fish and their aquaculture water, the fish and water samples were collected from three farms located in Assiut and Minia Governorates, Egypt. Aeromonas hydrophila was isolated from tilapia five organs including liver, kidney, intestine, spleen and gills with a percentage of 7.1, 6.5, 9.1, 5.1, and 11.7%, receptively, and from water samples with 59.7%. The isolates were molecularly confirmed as Aeromonas hydrophila in 70.9 % and 82.4 % of the tested isolates using 16s RNA and gyr-ß genes, respectively. Aeromonas hydrophila isolates revealed a marked resistance for the tested antibiotics; amoxicillin and novobiocin (100%), streptomycin (71.4%), chloramphenicol (57%), doxycycline and trimethoprim/Sulphamethoxazole (50%), colistin (43%), ciprofloxacin and norfloxacin (14%). The isolates showed multiple antibiotic resistance indexes ranging from 0.3 to 1. The present study highlights the Aeromonas hydrophila resistance and virulence, tilapia aquaculture health hazard to the human population, so adequate control measures should be applied. Furthermore, there is an essential need to promote an alternative non-antibiotic control in farmed fish. [ABSTRACT FROM AUTHOR]

The objective of this project was to develop live (LV), live attenuated (LAV), and autoclaved killed vaccines (AKV). The development of the vaccine involves utilizing two well-characterized strains of Streptococcus iniae (S. iniae), namely S. iniae 1 and S. iniae 2. S. iniae 2 was obtained from Department of Fish diseases, Faculty of Veterinary Medicine, Beni-Suef University, Egypt while S. iniae 1 strain was gifted from microbiology department, Egyptian Drug Authority, Dokki, Giza, Egypt. Pathogenicity test and lethal dose determination were performed. To conduct the experiment, apparently healthy Nile tilapia, Oreochromis niloticus (O. niloticus) of average weight 30±0.2g were divided into five experimental groups: T1 group, which served as a negative control and received saline; T2 group, which served as a positive control and received S. iniae 2; T3 group, which received an autoclaved killed vaccine for S. iniae 2; T4 group, which received a live attenuated vaccine for S. iniae 2; and T5 group, which received a live vaccine for S. iniae 1. At the end of the vaccination period, S. iniae 2 was introduced challenge to all groups. Serum samples were collected three weeks after vaccination to measure serum bactericidal activity, lysozyme activity, nitric oxide, alkaline phosphatase, and acid phosphatase. The findings demonstrated that the pathogenicity test reach 0 and 100% mortality rate for S. iniae 1 and S. iniae 2, respectively. Live attenuated vaccine had significantly higher protective rate than live vaccinations, while autoclaved vaccine had the best protective efficacy (88.2%). These results were confirmed through measurement some immune parameters as Serum bactericidal activity, lysozyme activity, nitric oxide, alkaline phosphatase and acid phosphatase. [ABSTRACT FROM AUTHOR]

Thiamethoxam (TMX) is a highly toxic systemic neonicotinoid pesticide and its entry into water bodies can greatly endanger human health and aquatic ecosystems. Little is known about the effect of thiamethoxam on Nile Tilapia. Particularly so this experiment was scheduled for three weeks to evaluate the toxic effects of thiamethoxam on productive performance of fish as well as water quality. The used insecticide was Actara 25 WG manufactured by Sygenta, Egypt and it was purchased from Egyptian Company for Seeds and Agricultural Chemicals. It is composed of 250 g/kg Thiamethoxam. A total of 200 Oreochromis niloticus with an average initial weight of 15 ± 5 g have been obtained from a commercial fish farm in Kafr Elsheikh province, Egypt. Fish were randomly allotted to five replicated treatments, and they were kept at a density of 10 fish / aquaria. Four different concentrations of the insecticide were tested with three replicates of fish for each treatment beside a control group where no insecticide was used. Tested concentrations of studied insecticide was selected according to lethal concentration 50 (LC50) for Thiamethoxam was 500 mg/l. Statistical analysis of the recorded data clarified that the levels of pH, dissolved oxygen levels (DO), oxygen saturation percentage (DO%) and salinity were significantly different between thiamethoxam treated groups and the control group. In addition, there was a significant difference in final weight and weight gain of fish under experiment in all treatments when compared with the control group. In addition, the lowest significance in the final weight and weight gain was observed at the high chronic dose. Finally, there were no significant differences in mortalities between various treatment groups and the control group with exception to high subacute dose that showed the highest significance of all groups, and it was clear that mortalities were increased with increasing thiamethoxam dose as no mortalities were observed in the control group. The present trial clearly showed the toxic effects of thiamethoxam on water quality of fish tank as well as performance and mortality rate in Nile tilapia fish that were live for three weeks in polluted water. Moreover, the result of the present study is of great public health importance because of thiamethoxam residue effects on human health. [ABSTRACT FROM AUTHOR]

Lake Nasser is the main source of fresh water in Egypt. This study concerns microbial assessment of water, sediments and fish (Oreochromis niloticus) collected from 5 inlets or khors of Lake Nasser (Rahma, Garf Hussein, Korosko, Toushka and Abu Simbel). The results indicate that the water and sediment samples collected from the southern part of Lake Nasser (Toushka) recorded a higher microbial load than the northern part. The highest number of pathogenic bacteria was also recorded in the southern part of Lake Nasser (Toushka and Abu Simbel). Also a higher bacterial load in/on fish (O. niloticus) was recorded at Rahma and Toushka sites. In general, the results of this study show that Lake Nasser is exposed to pollution, especially in its southern part. Therefore, regular monitoring and assessment are necessary to maintain the quality of Lake Nasser. [ABSTRACT FROM AUTHOR]

Background: Helicobacter pylori is a worldwide pathogen that affects both animals and humans with a wide environmental distribution, causing serious health problems in humans. This research has timely addressed the topic of new sources of H. pylori infection, which is currently a global issue, especially in developing countries. For this purpose, 115 Tilapia fish, 50 freshwater samples, and 88 fish-handlers' stool samples were investigated for the presence of H. pylori in Qena Governorate, Egypt. The applied techniques were antigen screening tests, culturing, and molecular methods through ureC gene amplification, and 16 S rRNA characterization. Results: Helicobacter pylori was detected in 7.83%, 14%, 4.35%, and 12% of the investigated fish and water samples by culture and PCR methods, respectively. Out of the total studied participants, 40 tested positive for H. pylori when screened by stool antigen test, of which 35 (39.77%), and 31 (35.23%) were confirmed by conventional and molecular techniques, respectively. The Fisher's exact test has shown a statistically significant correlation between H. pylori infection, sex, and age as risk factors, while the association was insignificant concerning the residence. Males contracted the infection at a higher rate than females (48.08% and 16.67%, respectively). Also, H. pylori infection rate was the highest among fish-handlers aged 36–45 years old (46.67%), followed by the 26–35 years old age group (39.53%). With regard to the residence, a higher occurrence rate was recorded in the rural (36.07%) than the urban population (33.33%). Helicobacter pylori isolates harbored the highest antimicrobial resistance against ampicillin (100%), metronidazole (95.24%), while the least antimicrobial resistance was recorded against levofloxacin (21.43%), and clarithromycin (26.20%). The phylogenetic analysis revealed a high degree of homology between the isolates selected from Tilapia fish, freshwater, and fish-handlers. Conclusions: Our data emphasized the role that fish and freshwater play in disseminating H. pylori infection as one of the diseases that has a significant public health issue. [ABSTRACT FROM AUTHOR]

The present study aimed to provide data on the effect of the High Dam on the morphological and meristic characteristics of Lates niloticus from two different Egyptian freshwater environments; Lake Nasser in Aswan City and the River Nile in Assiut City, Egypt. Therefore, twenty-six specimens of L. niloticus were collected from each site. The morphological characteristics and related index ratio to the standard length were determined. The results showed that the fish specimens from Lake Nasser were longer (mean 30.5± 8.8cm TL) than those from the Nile River (27.6± 4.2cm TL), and a strong correlation was detected between the different morphometric parameters to the standard length with different morphometric indices. The t-test showed significant differences between the total length, predorsal fin distance, postdorsal fin distance and prepectoral fin distance (P< 0.01). The means of indices related to the standard length, total length, predorsal fin distance, postdorsal fin distance, and prepectoral fin distance of L. niloticus collected from Lake Nasser are about 118.2, 44.2, 81.6, and 32.9 % SL, respectively, and are larger than the same indices of L. niloticus collected from the Nile River in Assiut City (109.3, 40.5, 77.0 and 26.7% SL, respectively). On the other hand, the other morphometric and all meristic parameters for the two locations showed insignificant differences. These findings suggest that differences in some morphometric characters may be due to the biometry of the species being influenced by the differences in the environments of Lake Nasser and the River Nile. Therefore, the continuous study of morphological features, that are related to the dams' constructions, environmental changes, as well as genetic confirmation, is recommended. [ABSTRACT FROM AUTHOR]

Bacterial diseases are one of the most challenging issues facing aquaculture sector. Pseudomonas aeruginosa (P. aeruginosa) has been regarded as one of the most significant threats to the fishing industry, which also affects public health. We aimed to elucidate the occurrence and antibiogram profile of P. aeruginosa recovered from Nile tilapia (Oreochromis niloticus) and smoked herring (Clupea harengus) with emphasis on their antibiotic resistance genes (blaTEM, blaSHV, blaOXA-1 and ampC) and virulence determinant genes (oprL and toxA). A total of 150 fish samples (110 diseased Nile tilapia, and 40 smoked herring) were collected randomly from retails of Gharbia Governorate, Egypt. The retrieved isolates were phenotypically characterized using standard methods of culturing and biochemical tests. Then, verified using molecular assay, 16S rRNA gene was detected in 100% of the tested isolates. The overall incidence of P. aeruginosa was 33.3%, out of which 45% from smoked herring and 29% from Nile Tilapia. The occurrence of P. aeruginosa in various infected organs of O. niloticus showed that the gills were the most obviously infected organ followed by kidney, liver, and spleen, respectively. A significant difference (P< 0.05) was noticed in the distribution of P. aeruginosa among O. niloticus internal organs. The phenotypic susceptibility to nine commonly used antimicrobial agents was detected using disc diffusion assay. The tested strains were extremely susceptible to ciprofloxacin, amikacin, and imipenem, whereas exhibited remarkable resistance to oxacillin, cefpodoxime, amoxicillin with clavulanic acid, ceftriaxone, and nalidixic acid. Interestingly, 100% of P. aeruginosa isolates were multiple antimicrobial resistant (MAR). Three resistance phenotypes profiles were identified with MAR index ranged from 0.4-0.5. Screening for antibiotic resistance genes revealed a diversity of β-lactamases in P. aeruginosa isolates, with blaTEM being the most dominant gene (100%), followed by blaSHV, and ampC with a total prevalence of 66.6% to all of them. The identified antimicrobial resistance phenotypes and genotypes were found to be significantly correlated. Subsequently, the distribution of virulence determinants in these strains was identified. These isolates had 100% prevalence of oprL and toxA virulence genes. In conclusion, the emergence of MDR P. aeruginosa in fish particularly ESBL and AmpC beta-lactamases producers could pose a potential health hazard to consumers. Thus, antimicrobial susceptibility must be continuously monitored to assess potential risks to human health. Ciprofloxacin, amikacin, and imipenem were the most efficient antibiotics for treatment of the identified P. aeruginosa, ESBL and AmpC beta-lactamases producers.blaOXA-1 [ABSTRACT FROM AUTHOR]

Pesticides are toxic and could negatively impact humans and the ecosystem. The Kitchener Drain is among the longest drains in Egypt and carries a wide range of wastewater from the agriculture sector, which contains pesticides and may pollute the ecosystem. Thus, water quality, human health risk, and pesticide accumulation in African catfish and Nile tilapia from the Kitchener Drain-Egypt. The water and fish samples were collected from Kitchener Drain in Kafr Elsheikh Governorate, Egypt, during the four seasons. The results indicated that heptachlor and diazinon were undetected during the four seasons. However, endosulfan, chlorpyrifos, and dicofol were detected in winter and autumn. Only p,p′-DDT was detected during spring. Endosulfan, heptachlor, and aldrin were detected in Nile tilapia during winter. Only heptachlor and aldrin were detected during spring. Endosulfan, heptachlor, dicofol, p,p′-DDT, chlorpyrifos, and diazinon were detected in the autumn season. In summer, dicofol and p,p′-DDT were detected, while endosulfan, heptachlor p,p′-DDT, aldrin, chlorpyrifos, and diazinon were not detected. In African catfish, endosulfan, heptachlor, dicofol, and p,p′-DDT were detected during winter, while chlorpyrifos, aldrin, and chlorpyrifos, aldrin, and diazinon were not detected. In the spring season, endosulfan, heptachlor, and aldrin were detected. Endosulfan, heptachlor, dicofol, p,p′-DDT, aldrin, chlorpyrifos, and diazinon were detected in the autumn season. Similarly, in the summer season, endosulfan, heptachlor, dicofol, p,p′-DDT, aldrin, chlorpyrifos, and diazinon were detected. The sequence of estimated daily intake (EDI) in Nile tilapia during the four seasons is heptachlor > endosulfan > dicofol > p,p′-DDT > aldrin > diazinon > chlorpyrifos. The sequence of EDI in African catfish during the four seasons is endosulfan > p,p′-DDT > heptachlor > aldrin > dicofol > diazinon > chlorpyrifos. In conclusion, the results confirmed the absence of a hazard index for consuming Nile tilapia and African catfish collected from the Kitchener drain. [ABSTRACT FROM AUTHOR]

This research was carried out to study the bacterial etiology of ulcerative syndrome in Nile tilapia (Oreochromis niloticus) and its associated environmental stressors. A total of 90 live and moribund Nile tilapia showing signs of ulcerative dermatitis were collected from various fish ponds in El-Sharkia Province, Egypt, during the summer seasons from June 2019 to August 2020. Collected fish were subjected to full clinical and postmortem investigation followed by bacteriological and molecular identification of the bacterial agents as well as histopathological examinations. Moreover, water samples from the fish sampling sites were collected and analyzed physiochemically and microbiologically. Furthermore, the pathogenicity of the isolated strains was assessed by challenging apparently healthy Nile tilapia to determine the LD50. Clinically, the examined fish exhibited ulcerative dermatitis as focal or fused large ulcers surrounded by red zones of hemorrhages at different body parts. Bacteriologically, Aeromonas veronii biovar sobria and A. caviae were isolated and identified. Moreover, 16S rRNA gene sequencing and phylogenetic analysis verified the identity of these species. Antibiogram profiling of the recovered Aeromonas sp. isolates showed complete resistance to ampicillin, with high susceptibility to gentamycin, trimethoprim/sulphamethoxazole, and erythromycin. Histopathological examination of the affected fish revealed epidermal necrosis with dermal edema and an influx of inflammatory cells into the dermis and hypodermis. The LD50 of A. veronii biovar sobria and A. caviae was estimated as 1.5 × 107 and 1.5 × 108 CFU/fish; respectively. The water temperature and ammonia concentrations recorded a significant rise (P ≤ 0.05) in July and August compared to June; however, the highest pH levels were recorded during August, followed by July. Also, the total bacterial load significantly increased (P ≤ 0.05). Finally, it was concluded that the improvement of water quality helps sustain the health of farmed fish. [ABSTRACT FROM AUTHOR]

One of the most important and distributed bacterial disease in freshwater fish in Egypt is flavobacteriosis disease that caused by the gram-negative bacillus Flavobacterium which infects fish under stressful conditions and causing high mortality. In this study we have attempted to identify the possible infection of three flavobacteria app. (F. columnare, F. covae, and F. davissi) out of 200 cultured African catfish Clarias gariepinus and Nile tilapia Oreochromis niloticus The Goal of this study was to isolate and characterize Flavobacteria species phenotypically, biochemically and detect the haemolytic virulence activity, beside evaluation antibiotics resistance activity of this bacterium. Despite, all flavobacteria species cause heamolysis to sheep blood agar that indicate to presence of heamolysine virulence gene but the F.columnare TIL2015 strain show no heamolysis on sheep blood agar. According to antibiotic sensitivity assay Gentamycin 30 μg, was the most effective antibiotic against the all tested Flavobacteria species, however F.columnare strains were sensitive against Doxycycline 30 μg, streptomycin 10 μg, beside gentamycin 30 μg. All isolates were resistant to amoxicillin 30 μg and Cefalexine 30 μg. [ABSTRACT FROM AUTHOR]

Parasitic infestation has a serious impact on fish health causing severe economic losses in fish farming as well as it has public health importance. This investigation was conducted on the prevalence of diagenetic encysted metacercariae (EMC) and its histopathological alterations in some freshwater fishes sampled from El - Riah El-Tawfiki, Qaliobia Governorate, Egypt. In this regard, a total of 600 randomly collected fish comprising 400 Nile tilapia (Oreochromis niloticus), and 200 African catfish (Clarias gariepinus) were examined macroscopically and microscopically from December 2020 to September 2021. The infested fishes showed white to yellowish cysts/nodules of variable size in different organs. The recorded EMC was identified as Clinstomum sp., Euclinostomum sp., Haplorichiaed sp., Pygidiopsisgeneta spp. Cyanodiplostomum spp, and Prohemistomulum spp. in the Nile tilapia and Prohestomatide spp. in African catfish. The overall prevalence of EMC was 29.25% in Nile tilapia and 22% in African catfish. The highest seasonal prevalence of EMC was 43% in summer for Nile tilapia and 34% in winter for African catfish. kidneys of Nile tilapia and musculature of African catfish recorded the highest tissue distribution of overall recorded EMC. Severe histopathological changes were observed in fish organs including gills, subcutaneous musculature, kidneys, liver, and ovaries. In conclusion, these results reflect the negative impacts of EMC on fish reproduction and general health status, therefore awareness about the control of fish parasites especially in natural resources should be conducted. [ABSTRACT FROM AUTHOR]

The present study described the most recent findings concerning the abundance and distribution of plastic in water, sediment, and fauna in the Nile River of Upper Egypt as an interesting research point. The findings revealed that plastics were abundant in the water, sediments, fish, and crayfish throughout the sites. The Nagaa Hammadi site has the highest abundance of meso- and macroplastics in its water and sediment. African catfish had the highest abundance of meso- and macroplastics compared to the other species, while Nile tilapia had no meso- or macroplastics in its alimentary canal or gills in all sites. The Edfu site has the highest abundance of mesoplastics in the alimentary canals of African catfish, while the Nagaa Hammadi site has the highest abundance of mesoplastics in the gills, and macroplastics appeared only in the alimentary canal of African catfish from the El-wasta site. Only mesoplastics were found in the crayfish's alimentary canal, with the Nagaa Hammadi site having the highest abundance. No macroplastics were detected in the crayfish's gills or alimentary canal. Additionally, this work lets us understand how plastics behave in freshwater environments, and it is a step toward decision-makers taking appropriate measures to reduce their risk. [ABSTRACT FROM AUTHOR]

Until the 1960s, Lake Maruit was one of Egypt's most productive coastal brackish lakes. Continuous polluted discharge from Alexandria city resulted in long-term deterioration. The Egyptian government started a lake restoration program in 2010. Biological linkages between pelagic and benthic communities were assessed in November 2012 using parasitism and predation. This study examined ectoparasites infesting tilapia fish from 300 samples. The platyhelminth ectoparasite, Monogenea, and parasitic-copepod Ergasilus lizae were detected. Platyhelminthes parasitized Oreochromis niloticus and Oreochromis aureus, whereas the crustacean parasitized Coptodon zillii. The parasitic prevalence was low for Cichlidogyrus sp. and Ergasilus lizae. Benthic biotas were similar across basins. Fish abundance does not respond directly to benthic biotic components. Phytoplankton and benthic microalgae were not the main fish diet. Data on Halacaridae and fish clustered, indicating that either Halacaridae responds to their environment like fish or fish prey upon them because of their size. Linear correlations between pelagic, benthic biota, and parasite-infected fish indicate parasites may control their hosts. Some bioindicators indicate that stressed ecosystems differ from unstressed ecosystems. Fish species and biota abundances were low. Inconsistency in the food web and an absence of direct interactions between prey and predators are bioindicators of disturbed ecosystems. The low prevalence of ectoparasites and lack of heterogenous distribution of the various examined biota are bioindicators of habitat rehabilitation. Ongoing biomonitoring to better understand habitat rehabilitation is suggested. [ABSTRACT FROM AUTHOR]

This study aimed at evaluating the immunological status of Oreochromis niloticus (O. niloticus); so, a total of 120 O. niloticus were collected from different farms located in Kafr El-Sheikh Governorate in Egypt during the period from January 2021 to January 2022. The fish were surveyed for commonly encysted metacercariae present in different organs such as gills, spleen, liver, kidney, and muscles. The collected encysted metacercariae were of the family Cyathocotylidae (Prohemistomum vivax) with a prevalence of 25%. Different cell-mediated immune responses such as Major histocompatibility class II alpha (MHC-IIα), Toll-like receptor 7 (TLR-7), Interleukin (IL-8), and Clusters of differentiation 4 (CD4) were assessed in different organs such as gills, spleen, liver, kidney, and muscles which revealed an elevation in different genes in infected organs as a reaction from the body against parasitic infection. In addition, the liver enzymes; aspartate aminotransferase (AST), and alanine aminotransferase (ALT), were assessed in the serum of O. niloticus as well as blood glucose, cortisol levels, and lysozyme activity were estimated to record higher levels in the infected fish in comparison with the control non-infected ones. [ABSTRACT FROM AUTHOR]

The current research was conducted to assess potential health risks for human consumers and the effects of various anthropogenic actions on the heavy metal load in O. niloticus gathered at various sites in the Damietta branch (Egypt). In fish muscles, metals accumulated in the following sequence: Fe > Zn > Cu > Mn > Pb. Among all sample locations, station 6 recorded the greatest values for metal pollution index (MPI) and hazard quotient, aligned with a higher metal pollution index. The current study may serve as a warning to regular consumers, especially given the high consumption rates of the Oreochromis type. In Oreochromis niloticus, metal buildup exhibited tissue-specific patterns. The liver and gill tissues were high bio accumulators compared to muscle tissues, as evidenced by the computed bioaccumulation factor and metal pollution index. The hazard index (H.I.) calculation showed that individual metals had a modest H.I. However, the combined effects of total metals posed a severe risk to eaters. [ABSTRACT FROM AUTHOR]

Clinostomum (a digenetic trematode) infests tilapia and causes several disease problems. Moreover, Clinostomum has zoonotic importance. Pseudomonas putida is regarded as one of the significant pathogens that have threatened freshwater fishes resulting in high mortality and severe economic loss. This study investigates the phenotypic and genotypic characterization of P. putida recovered from both fish and their Clinostomum that may bond the Clinostomum infestation to the transmission of P. putida in Tilapia fishes. Fifty P. putida isolates from freshly dead moribund fishes and their Clinostomum, from the Nile River at Al Bahr Al Aazam, Giza, were studied. Also, 5 isolates were retrieved from the water. Biochemical, antibiogram, species-specific PCR and phylogenetic analysis of 16S rRNA gene were performed. Also, Water physicochemical analysis was done. The analysis of water showed bad water quality in summer. P. putida isolates from fish, Clinostomum and water showed the exact antimicrobial susceptibility profile. The phylogenetic analysis of partial 16S rRNA gene sequence revealed that P. putida isolates from fish, Clinostomum and water showed 100% similarity with each other. This result, combined with our isolation of viable P. putida from Clinostomum, proposes the transmission of this serious pathogen through the parasite. In conclusion, the high Clinostomum infestation could play a significant role in the transmission and high prevalence of P. putida in Tilapia fishes in the Nile River at Al-Bahr Al-Azam, Giza. [ABSTRACT FROM AUTHOR]

Arsenic (As) and mercury (Hg) concentrations in the sediment and tissues of Oreochromis niloticus fish from a Nile River canal (Muweis Canal), Egypt, were subjected to an investigation between May and July 2022 at six stations along the canal. Concentrations of As and Hg were determined via an atomic absorption spectrophotometer. The results showed that the concentrations of metals in the liver, muscle and sediment varied significantly among the different sampling sites. The contamination factor (CF) and potential ecological risk index (RI) indicated a considerable risk for aquatic life. For O. niloticus consumption, the estimated daily intake (EDI) of Hg was less than the permissible daily intake. However, the target hazard quotient (THQ) and target cancer risk (CR) values for As exceed the acceptable value range, suggesting a risk of cancer for consumers. Therefore, the continuous monitoring for heavy metals in Muweis Canal and similar localities in Egypt should be improved to preserve ecological and human health. [ABSTRACT FROM AUTHOR]

Carcinogenic and other health risks associated with consuming fish have been evaluated using the selected six fish species including Dicentrarchus labrax, Clarias gariepinus, Sarotherodon galilaeus, Oreochromis aureus, Oreochromis niloticus and Tilapia zillii from Idku Lake, Egypt. To estimate the non-carcinogenic (estimated daily intake (EDI), target hazard quotient (THQ) and carcinogenic human health risks (CR), the concentrations of heavy metals (Fe, Cr, Ni, Pb and Cd) in the liver and muscles tissue of six fish species were addressed. The estimated daily intake (EDI) showed that the highest concentration was in iron but this value was the only value in the heavy metal concentrations that didn't exceed the permissible limit. The total values of this indicator (tTHQ) were determined for fish species, and a noticeable increase was recorded in the values for the lead element. However, the values range are less than 1.00, indicating no discernible health. Clarias gariepinus had values of 1 that can affect human health in the long term. While for carcinogenic human health risks (CR), the highest value was recorded in the liver of clarias gariepinus fish, and it exceeds the recommended ratios. All the remaining values of heavy metals were within the recommended ranges, which indicates that there is no tangiblehealth risk to humans. [ABSTRACT FROM AUTHOR]

Fish is considered the main source of protein in Egypt, especially due to the shortage of red meat. In this study, one hundred random samples of Nile fish represented by Clarias lazera (C. lazera) and Oreochromis niloticus (O. niloticus) (25 of each fish species) and marine fish represented by Sardina pilchardus (S. pilchardus) and Mullus barbatus (M. barbatus) (25 of each fish species) were collected at different periods of time from various fish markets in Shibin Elkom city, Egypt. The samples had been analyzed using an atomic absorption spectrophotometer for the detection of mercury (Hg), lead (Pb), cadmium (Cd), and arsenic (As). In addition to Lactobacillus rhamnosus (L. rhamnosus ) used in decontamination of artificially inoculated fish fillet with different heavy metals. The mean values of Hg were 1.44 ± 0.03 of 1.13 ± 0.01, 0.81± 0.02 and 0.59± 0.01 mg/kg in C. lazera, O. niloticus, S. pilchardus and M. barbatus, respectively. Also, for Pb values were 0.78 ± 0.01, 0.61 ± 0.01, 0.39 ± 0.02 and 0.08 to 0.53 mg /kg C. lazera, O. niloticus, S. pilchardus and M.barbatus, respectively. The mean values of Cd were 0.43± 0.01, 0.26± 0.01, 0.04 to 0.49 and 0.05± 0.01mg/ kg in examined C. lazera, O. niloticus, S. pilchardus and M.barbatus, respectively. Meanwhile, as residues were 0.29± 0.01 and 0.16 ± 0.01 mg/kg in C. lazera and O. niloticus only. The L. Rhamnosus can reduce Hg, Pb, Cd and as experimentally inoculated to fish fillets with percentages 67.7%, 76.3%, 75% and 59%, respectively. [ABSTRACT FROM AUTHOR]

In this study, a sustainable and eco-friendly method was used to prepare zinc oxide nanoparticles (ZnO-NPs) using a sea cucumber aqueous extract. Then, ZnO-NPs were characterized by instrumental analysis (UV-vis, HR-TEM, XRD, FT-IR, and DLS) and evaluated for their possible antibacterial, antifungal, and insecticidal activities. Additionally, the toxicity of ZnO-NPs was evaluated in vivo against Nile Tilapia (Oreochromis niloticus). The sea cucumber was collected from the Gulf of Suez (Red Sea) at Al-Ain Al-Sokhna coast in Egypt and identified as Holothuria impatiens. The prepared Hi-ZnO-NPs peaked at 350 nm in UV–Vis spectral analysis. They showed quasi-spherical shaped particles with sizes ranging from 13 nm to 47 nm and a predominate size of 26 nm as indicated by HR-TEM. The XRD pattern of Hi-ZnO-NPs revealed a crystalline phase with an average size of 17.2 nm as calculated by Debye–Scherrer equation. FTIR analysis revealed the possible role of H. impatiens biological molecules in the biosynthesis process of ZnO-NPs. Hi-ZnO-NPs showed a negative zeta potential of −19.6 mV, demonstrating moderate stability. Biosynthesized Hi-ZnO-NPs revealed broad antimicrobial activity against Gram-positive bacteria (S. aureus ATCC 25923 and E. feacalis), Gram-negative bacteria (S. typhi, K. pneumonia and E. coli), and filamentous fungi (Aspergillus niger). Hi-ZnO-NPs demonstrated larvicidal activity against the mosquito, Culex pipiens (LC50 = 2.756 ppm and LC90 = 9.294 ppm), and adulticidal action against the housefly, Musca domestica (LD50 = 4.285 ppm and LD90 = 22.847 ppm). Interestingly, Hi-ZnO-NPs did not show mortality effects against Nile tilapia fish (Oreochromis niloticus), highlighting the potential safety of Hi-ZnO-NPs to highly exposed, non-target organisms. However, histopathological and hematological investigations provided dose-dependent impacts of Hi-ZnO-NPs to Nile tilapia. Overall, data provide an eco-friendly approach for synthesizing novel Hi-ZnO-NPs with multiple biomedical properties and potentially low toxicity to Nile tilapia fish. [ABSTRACT FROM AUTHOR]

Fish is considered as important source of animal derived protein, omega-3-fatthy acids, minerals such as calcium, phosphorus, iodine, and vitamins. Among the fish species, Tilapia nilotica is the most famous fish in Egypt due to its ease culturing, short production cycle, cheap price, and therefore play fundamental roles in food security, particularly in the human supply of the anumal-derived protein. Fish during its production till delivery to the consumer's table might be exposed to a vast array of microbial contaminants either originated from its surrounding eniveronment or via cross contamination from the angler's hands, during transportation, and storage. Therefore, tilapia might act as a potential source of spreading of foodborne pathogens to the consumers. However, few reports had investigated the microbal quality of tilapia, particularly in Egypt. Therefore, this review was undertaken to report literatures studying the prevalence of some foodborne pathogens in tilapia fish in Egypt, the factors that affect the microbial quality of the fish, and some recommendations in order to extend the shelflife and improve the microbial quality of Tilapia nilotica. This reviw concluded that tilapia is eligible for contamination with a vast array of microorganisms such as Enterobacteriacae, Staphylococcus aureus, Shewanella putrefaciens, Corynebacterium urealyticum, Aeromonas hydrophila, and Flavobacterium spp. Therefore, it is highly recommended to have efficient cooking of fish either via boiling, grilling, panfrying, dipping in liquid smokes, irradiation, ozonization, and addition of smone natural addirives such as lemon juice. [ABSTRACT FROM AUTHOR]

Mariout Lake is one of the Northern Nile-Delta Lakes in Egypt that receives agricultural, industrial and domestic effluents through several drains. The present study aims to evaluate the levels of some heavy metals (HMs) in water and edible parts of Oreochromis niloticus in Mariout Lake, in addition to studying several pollution indices and potential human health risks. The levels of the studied HMs in water were in the order of Fe > Zn > Mn > Pb > Cu > Ni > Cd. However, results of the pollution index, that concerns the effect of individual metal, concluded that Cd and Pb in water had serious pollution effects for aquatic life, while Cu, Fe, Mn, Ni, and Zn had not any pollution effects at different locations in the lake. The indices of the composite effects of all HMs (Metal Index and Heavy Metal Pollution Index) indicated the high pollution of Mariout Lake water, which may cause adverse effects on fish and different aquatic organisms. On the other side, the bioaccumulation factors of HMs in edible parts of O. niloticus were in the order of Zn > Cd > Cu > Ni > Pb > Mn > Fe. Although the target hazard quotient for all metals was less than the non-hazardous limit (THQ < 1), the non-carcinogenic hazard index (HI = 1.24) was classified in the moderate hazard risk level (1 < HI < 10) indicating low potential adverse effects on the exposed population due to consumption of O. niloticus caught from Mariout Lake. [ABSTRACT FROM AUTHOR]

Mitotic chromosomal aberrations and DNA polymorphism (RAPD marker) were carried out on the Nile tilapia Oreochromis niloticus collected from five sites in Minia governorate, Egypt to test their applicability as biomonitors for heavy metal contaminants of water. The diploid chromosome number of O. niloticus population was 2 n = 44. Different types of chromosomal aberrations were recorded (e.g., deletion, ring, centromeric attenuation, end‐to‐end association, dicentric chromosome, stickiness chromosomes, endomitosis, fragments and chromatid gap). The chromosomal aberrations varied between O. niloticus population collected from five sites, and the most common type was ring (R) chromosomes. Samples obtained from Bahr Yousef and Irrigation drain exhibited the highest aberration frequency. The frequency of chromosomal aberration was positively correlated with the concentration of heavy metals where their concentration in the surface water of Irrigation drain and Bahr Yousef exceeded the limits defined by WHO as well as the concentration of Pb in muscles. The RAPD marker was also used to identify genetic variation among Nile tilapia samples collected from five different water sources. It created polymorphic and unique bands that can be used as genetic markers to track DNA variations. The dendrogram also revealed that exposure to heavy metal pollution causes gradual accumulation of variance, whereas areas subjected to environmental stress showed higher genetic variation and clustered together. [ABSTRACT FROM AUTHOR]

The present work aimed to investigate the prevalence of zoonotic parasites in the Nile and cultured freshwater fish in El-Minya Governorate, Egypt. A total of 200 fish samples (100 Nile and 100 cultured) included 50 for each; Tilapia nilotica (Oreochromis niloticus), catfish (Clarias gariepinus), bajad (Bagrus bajad) and carp fish (Cyprinus carpio) were randomly collected from markets and some fish farms from El-Minya city. Out of 200 examined fish 187 samples were infested by one or more zoonotic parasites with a prevalence of 93.5%, highest infestation rate was detected in Nile fish 100 % compared to 87 % in farmed ones. The total prevalence of Encysted metacercaria (EMC) among examined fish was 86.5%; it was 88% and 85% in Nile fish and farmed fish, respectively. Microscopic (EMC) was detected in 83 and 73% of Nilefish and farmed fish, respectively, while macroscopic (EMC) was detected in 5 and 12% of farmed fish and Nile fish, respectively. Microscopic (EMC) was identified as: Cynodiplostomum (EMC) and Prohemistomum (EMC) while, macroscopic (EMC) was identified as Clinostomum phalacrocoracis. On the other hand, the total prevalence of Ichanthochephala among examined fish was 8 %, it was 13 and 3 % in Nile fish and farmed respectively, while the total prevalence of Cryptospordium spp and Capillaria spp. among examined fish was 39 and 14.5 %, respectively. The current study revealed a variable prevalence of different zoonotic parasites in different species of examined fish, which represents a potential risk to public health if consumed raw or improperly cooked. [ABSTRACT FROM AUTHOR]

Microbial infections in tilapia aquacultures cause severe economic losses in Egypt. They appear in summer with other stress factors such as low oxygen and high ammonia levels in aquaculture. Streptococcosis lead to severe losses in tilapia farming, especially in third countries. Microbiological and histopathological examinations are very important diagnostic tools in distinguishing fish microbial infections. This study aimed to isolate, identify, and characterize the most common bacterial fish pathogen recovered from Nile tilapia private farm around El Salam Canal, at Ismailia governorate. In addition to detection the main histopathological lesions were done. The highest rate of bacterial isolation was Streptococcus agalactiae with 29.16% from all samples. Grossly the infected fish showed hemorrhagic septicemia, and exophthalmia. Histopathological examination revealed severe hyperemia of gill filaments and gill arch, chronic enteritis, hydropic degeneration of the liver, edema and hemosiderosis of the spleen, necrosis of muscle and hemorrhage and myocardiolysis of heart. [ABSTRACT FROM AUTHOR]

Aeromonas hydrophila, is an important foodborne bacterial disease in the aquaculture. The present study aimed to investigate the prevalence of Aeromonas species, virulence genes associated in A. hydrophila and to determine the antimicrobial susceptibility of Aeromonas spp. isolated from fish samples (tilapia, mugil, tuna, saurus, pagrus and shrimp) collected from Zagazig city markets, Sharkia Governorate, Egypt. Aeromonas spp. was isolated with a percentage of 39.3% of all examined fish samples. Four Aeromonas species (A. hydrophila, A. caviae, A. fluvialis and A. sobria) were isolated from the tested fish samples (12%, 15.3%, 2.7% and 9.3%, respectively). A. hydrophila was only isolated from Tilapia, Saurus and Shrimp samples (16%, 28% and 28%, respectively). Aerolysin (aerA) and haemolysin (ahh1) were expressed in 100% and 75% of the A. hydrophila isolates. Antibiotic susceptibility testing of Aeromonas spp. revealed marked resistant for testing antibiotics; Ampicillin (100 %), Erythromycin (100 %), Tetracycline (83.3 %), Sulphamethoxazol (75 %), Cefotaxime (50 %) and Cephalothin (50 %). Dipping of Nile tilapia in lemon juice 5% for 2 h reduced A. hydrophila counts by 0.45 log cfu/g (64.44%). In conclusion, the present study confirms contamination of fish by Aeromonas spp. Immersion of fish in in lemon juice 5% is an efficient policy for reducing A. hydrophila in fish. [ABSTRACT FROM AUTHOR]

Aquaculture is a crucial sector for Egyptian food production, providing a cheap source of animal protein while securing income and employment for a substantial part Egypt's population. Nile tilapia (Oreochromis niloticus) is the most commonly produced fish, usually farmed in earthen ponds around the Northern Delta Lakes. A common practice among farms is to fertilize ponds with chicken manure (CM) in order to increase nutrient levels and promote phytoplankton, consumed by the fish. However, with reports of use of antibiotics in Egypt's poultry sector, and that CM contains residues of antibiotics, antibiotic resistant pathogens and antibiotic resistance genes (ARGs) are production benefits large enough to compensate a potential health hazard? Using production data from 501 aquaculture farms and fish pond sediment from 28 ponds we evaluated potential benefits in yields and profitability for farms using CM for fertilization, and used qPCRs to screen sediments for three antibiotic resistance genes coding for resistance to the most commonly used antibiotics in the poultry sector. The analysis showed no significant benefits to fish yields or profitability in farms where CM was applied, but a risk of significantly increased nutrient loads. Meanwhile, we detected increased abundances of tetA and tetW resistance genes in fish pond sediment where CM was applied. With the risk of disseminating ARGs and causing eutrophication of local waterways, we recommend that Egyptian tilapia pond farmers refrain from using CM and adopt best management practices for increasing farm profitability in order to to reduce environmental and health hazards. • Consequences of fertilizing tilapia ponds are investigated across Northern Egypt. • Chicken manure addition increases eutrophication potential but not profitability. • Positive correlation between fertilization and abundance of resistance genes. [ABSTRACT FROM AUTHOR]

Despite being one of Egypt's most significant fish production resources, Lake Manzalah (Northeast Egypt) is subject to substantial inputs of pollution from domestic, agricultural and industrial sources. The liver and gonads of Oreochromis niloticus were evaluated for histological and ultrastructural alterations in the current study to monitor the possible effects of Lake Manzalah pollution at two different areas, (A) near Hadous drain and (B) near the Bahr El-Baqar drain during autumn and spring seasons. Heavy metal concentrations in water, sediment, and fish tissues were assessed. The results showed that Fe, Mn, and Ni levels were greater than the standard allowable values in area B compared to area A, and in autumn rather than spring. Both studied areas showed heavy metal deposition in O. niloticus tissues with greater values in autumn, compared to spring. The maximum concentration of the heavy metal in tissues was found in the fish liver of area (B) in autumn. In the autumn and area B, there were significant histopathological and ultrastructural damages to the liver and gonads. It was concluded that, the noted biomarker responses were possible indicators of health deterioration in Lake Manzalah fish populations. Long-term monitoring is therefore required to assess the eco-health of the Manzalah Lake ecosystem by using bio-indicator species such as Oreochromis niloticus, which offer accurate, dependable measures of environmental quality. [ABSTRACT FROM AUTHOR]

Vibriosis is a common disease in aquaculture. Nile tilapia (Oreochromis niloticus) farmed within some commercial fish farms in Kafr El-Sheikh governorate Egypt showed signs of disease and exhibited heavy mortality. In order to get to the root of the problem, ninety moribund tilapia were sampled from the affected fish farms and subjected to bacteriological and molecular examinations. Biochemical characterization of bacterial isolates was performed via the API 20E analytical system. All examined fish samples were infected with Vibrio species. Eighteen Vibrio isolates, V. mimicus (n = 12), and V. cholerae (n = 6) were taken randomly for molecular characterization and further analysis. Isolates were genotyped via sequencing and alignment of the recA gene. Isolates possessed numerous virulence traits, including the production of hemolysins, proteases, lipases, and nucleases. The prevalence of ompU, vmh, vpsR, and flrA virulence genes in Vibrio strains was 61.1%, 66.6%, 27.7%, and 33.3 %, respectively. The blaTEM (55.5%), apHAI (50%), and qnrVC (27.7%) antibiotic resistance genes were recorded in Vibrio strains. All Vibrio isolates (100%) were resistant to ampicillin 10 μg and amoxicillin 30 μg, while they showed high sensitivity against florfenicol 30 µg (83.3%) and ciprofloxacin 5 µg (77.7%). Challenge experiments in Nile tilapia confirmed pathogenicity of the isolates. Fish showed symptoms of septicemia and high mortality was observed. Infections induced numerous histopathological alterations in diseased fish. This is the first report of V. mimicus outbreaks associated with mass mortality in Egyptian farmed Nile tilapia. The findings form the basis for future development of effective control and preventive measures against one of the most infectious pathogens that affect fish and humans. [ABSTRACT FROM AUTHOR]

Recently, the high cost of aquafeed affected fish farming feasibility in some countries, including Egypt. The imported soybean meal and corn ingredients consume a large amount of the hard currency, thereby increasing feed prices. Thus, the current study investigated the different sources of soybean and corn on the performances of Nile tilapia. Fish fed with the diet I (based on Egyptian soybean meal cultivar and cornmeal cultivar) or diet II (based on imported soybean meal cultivar and cornmeal cultivar) in a 90-day feeding trial. The results showed no marked effects on the growth performance, protein efficacy ratio, and FCR in the case of fish-fed diet I or diet II. No histological alterations were observed in the skeletal muscle, hepatopancreas, spleen, and intestines, while the diet I-fed group showed normal architecture of the above-listed organs. The expression of liver and muscle IGF-1 showed no changes in fish-fed diet I or diet II. No diet-related variations were observed in IL-1β expression in the spleen but increased regulation in the liver of the diet II group compared to the diet I group. Furthermore, significant upregulation of SOD and HSP70 genes was seen in the spleen and liver of the diet II-fed group. We conclude that the inclusion of the Egyptian soybean meal cultivar and cornmeal cultivar (diet I) did not reduce the growth performance and immune-related genes compared with the imported soybean meal cultivar and cornmeal cultivar (diet II). [ABSTRACT FROM AUTHOR]

Fishes are affected by the bacterial load and species present in the surrounding area. Therefore, bacterial load on/in fishes can be used as an indicator of aquatic pollution. Bacterial load was estimated in fish tissues of different tilapia species (Oreochromis niloticus, Sarotherodon galilaeus and Tilapia zilli) collected from the entrance and middle El-Ramla and Abu Simbel Khors. Results indicated that fishes of Abu Simbel Khor recorded higher bacterial loads than those of El-Ramla Khor, also fishes of entrance khors recorded higher bacterial loads than the middle. Salmonella sp. and Escherichia coli were detected in fish samples collected from Abu Simbel Khor more than fishes collected from El Ramla Khor. Vibrio chorella was detected in fish samples collected from El Ramla Khor more than those collected from Abu Simbel Khor. The results reflect the exposure of Lake Nasser Khors to various pollutions, especially in its southern part. Here, it is necessary to follow up fishing and tourism boats, also coastal farms around the Khors, to reduce or prevent the causes of pollution of Lake Nasser and its Khors. [ABSTRACT FROM AUTHOR]

Heavy metal levels (Copper, zinc, lead, and cadmium) in water and fish (Nile tilapia) have been evaluated in three different locations in (ELKapoty) Lake Manzala. Metals' quantities in both fish tissues and water were measured. Fish samples with weights ranging between 78.7 and 42.3gm varied significantly by area and season. All metals under study peaked in summer and dropped in winter. The levels of different metals in fish tissues and water were ordered in the correct sequence: Copper > zinc > Lead > cadmium. In water, the mean concentrations of metals were as follows: Cd is 0.006 mg/L, Pb is 0.007mg/L, Zn is 0.032mg/L, and Cu is 0.007mg/L. The water's cadmium amount was higher than the limit allowed for drinking water. The mineral concentration in fish organs was much higher than in water. The gills of the tested fish had the greatest mineral concentration, while the muscles showed the lowest. Despite the fact that Lake Manzala was polluted with heavy metals, the amount of minerals in the fish's muscles did not overpass the limits allowed, making the fish safe. [ABSTRACT FROM AUTHOR]

Aquaculture is a promising of the Nile tilapia (Oreochromis niloticus, L.), an important issue in Egypt. The present study's objective was to use short sequence repeats markers (SSRs) in the early sexing of O. niloticus. Molecular markers identification in fish includes SSRs markers that were very useful for investigating sexdetermination system, sex-related genes, and sex chromosomes. The fin-clip tissue of examined fish was used for DNA extraction and the amplification of SSRs and sex determination; twenty primer pairs were tested. The results showed that, from the tested 21 primers of SSRs markers, four primers had significant differences between males and females. It was observed that females were homozygous, and males may be heterozygous or homozygous for the alternative bands. The females were homozygous, males were heterozygous for two SSRs markers, the females were homozygous, and males were homozygous for the alternative alleles for the other two markers. In conclusion, the results of the present study and the previous ones confirm the possibility of using short sequence repeats markers (SSRs) in the sex determination of fish species, including Nile tilapia (Oreochromis niloticus, L.). SSRs markers could be used in the early sexing detection of the Nile tilapia breeding programs and for producing supermale YY without needing progeny test. [ABSTRACT FROM AUTHOR]

Background: Streptococcus agalactiae (Group B streptococcus, GBS) induces a serious infection that can harm not only aquatic life but also humans and other animals. In a fish farm in southern Egypt, Nile tilapia (Oreochromis niloticus) has developed an epidemic with clinical symptoms resembling piscine streptococcosis., Results: Initial microscopic inspection of the affected fish brain and kidney indicated the presence of Gram-positive cocci. S. agalactiae was effectively isolated and identified using nucleotide homology of the 16S rRNA and species-specific PCR. The partial 16S rRNA sequence was deposited in the GenBank database at the NCBI and given the accession number MW599202. Genotyping using RAPD analysis indicated that the isolates in the present study belonged to the same genotypes and had the same origin. The challenge test, via immersion (9.2 × 10 7 , 9.2 × 10 6 , and 9.2 × 10 5 CFU/ml for 1 h) or intraperitoneal injection (4.6 × 10 7 , 4.6 × 10 6 , and 4.6 × 10 5 CFU/fish), elicited clinical symptoms resembling those of naturally infected fish with a mortality rate as high as 80%. The ability to create a biofilm as one of the pathogen virulence factors was verified. Zinc oxide nanoparticles and the ethanolic leaf extracts of nine medicinal plants demonstrated considerable antibacterial activities against the tested S. agalactiae strain with low minimum bactericidal concentrations (MBC) and minimum inhibitory concentrations (MIC). The ethanolic leaf extracts from Lantana camara and Aberia caffra showed potent antibacterial activity with MBC values of 0.24 and 0.485 mg/ml, and MIC values of 0.12 & 0.24 mg/ml, respectively., Conclusion: This study isolated S. agalactiae from O. niloticus mortalities in a fish farm in Assiut, Egypt. The pathogen persists in fish environments and can escape through biofilm formation, suggesting it cannot be easily eliminated. However, promising findings were obtained with in vitro control employing zinc oxide nanoparticles and medicinal plant extracts. Nevertheless further in vivo research is needed., (© 2024. The Author(s).)

River pollution can harm human health through direct contact, drinking water, and the consumption of contaminated fish and irrigated agricultural products. Surface water and Nile tilapia (Oreochromis niloticus) samples were collected monthly from July 2022 to June 2023 at three sites (El-Rahawy, Sabal, and Tala) along the Rosetta Nile branch in Egypt to monitor the presence of eight trace elements. The potential human health risks from consuming contaminated fish were also assessed. Iron and manganese were consistently detected in all water samples across most seasons and locations, with concentrations generally below the WHO permissible levels. All 72 analyzed fish muscle samples were found to contain trace elements. The mean concentrations of metals in the fish muscle samples, in descending order, were: iron > zinc > copper > manganese > tin > antimony > lead > mercury. Significant spatial and seasonal variations were observed in both water and fish samples. El-Rahawy was identified as the most contaminated site, with summer exhibiting the highest contamination rate compared to other seasons. Fish samples collected from El-Rahawy demonstrated the highest bioconcentration factor (BCF) values for most elements, particularly mercury, lead, iron, manganese, and antimony. Target hazard quotient (THQ) calculations for the trace elements in Nile tilapia muscles revealed that all trace elements, except antimony, had THQ values below 1, suggesting that consuming Nile tilapia from these sites is unlikely to cause adverse health effects. However, THQ values for antimony exceeded the threshold of 1, indicating a potential health risk for consumers. Although the detected trace elements in the fish were below the permissible toxicity limits, some could pose a future threat to human health, necessitating further studies, ongoing monitoring, and preventive measures., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Vibrio species are major sea foodborne pathogens that cause gastroenteritis as a serious disease of human public health due to the consumption of undercooked or raw fish. In the current study, a total of 100 fish samples (Nile tilapia, Nile perch, Meagre, and Sea bass) were collected randomly from retail markets in Egypt to investigate the prevalence of Vibrio species. The results revealed that Vibrio species isolated with an overall percentage of 52% of all examined fish. Bacteriological and chemical examinations revealed 42.3% V. parahaemolyticus, 26.92% V. mimicus, 19.23% V. alginolyticus, 9.62% V. vulnificus and 1.92% V. cholera. Antibiotic sensitivity declared high resistance of the isolates to different antimicrobial agents used in Egypt including Ampicillin (100%), Nalidixic acid (88.3%), Streptomycin (84.2%), Sulphamethoxazol (70.7%) and Oxytetracycline (64.8%) and it had sensitivity to Amikacin (94%), Ciprofloxacin (70.5%), Gentamicin (58.9%) with an average MAR index of 0.576. By polymerase chain reaction, all examined Vibrio isolates were positive for 16SrRNA specific for Vibrio spp. and harbored toxR gene virulence gene. Finally, dipping of tilapia in lemon juice 5% for 2 h reduced V. parahaemolyticus count by 0.42log cfu/g (62.08%). Consequently, hygienic measures should be approved to control the contamination of fish in the markets and the aquatic environment. Regular monitoring of fish for antibiotic resistance by Vibrio species, and their molecular characterization is necessary to improve the safety of seafood. Dipping fish in lemon juice is an efficient strategy for reducing V. parahaemolyticus load in fish. [ABSTRACT FROM AUTHOR]

Lamproglena monodi Capart, 1944 adult females were first described from the Democratic Republic of the Congo and have been redescribed seven times from different cichlid species in Egypt, Burkina Faso and Brazil, all showing morphological variation. The adult male was first described from Lake Victoria and the Victoria Nile in Uganda. Copepods from the present study were collected from the gills of Oreochromis niloticus (Linnaeus, 1758) from Kibos Fish Farm, Kenya (between December 2017 and April 2018) and Sharqia Governorate (June 2019) and El-Minia (between July and December 2018) in Egypt. They were identified as L. monodi based on morphology and genetic data. Parasites were studied morphologically with the aid of light microscopy and scanning electron microscopy (SEM), and female infection levels calculated. Genetically, the specimens were studied using fragments of 18S and 28S rDNA. SEM analyses revealed additional diagnostic morphological features for the three adult males (elusive) and 249 females. These data were used to update the identification key for male Lamproglena species. Prevalence, mean intensity and mean abundance of the females were calculated as 13.5%, 8.6 and 1.2 respectively. Both 18S and 28S rDNA fragments confirmed the distinctness of L. monodi from previously characterised Lamproglena species, with distances of 1.22–1.94% (17–27 bp) for 18S rDNA and 15.66–18.1% (111–128 bp) for 28S rDNA. Haplotypes obtained from male and female specimens were identical, confirming the identity of the male specimens. This is the first genetic study of Lamproglena from Africa, the first SEM and genetic study of male L. monodi, and the first geographical report of this parasite from Kenya. The male and molecular data reported herein provide a useful point of reference for future Lamproglena studies. [ABSTRACT FROM AUTHOR]

El-Manzala Wetland is known to be of the most significant sources of inexpensive different fish species for human consumption in Egypt. The Lake receives pollution from various sources; domestic wastewater, industrial wastewater, and agricultural drainage directly without any treatments, which leads to many environmental disorders. The following research was conducted for lake water quality evaluation and how it impacts the expression of the aromatase (CYP19a&b) genes in Oreochromis niloticus tissues at different locations of El-Manzala Lake. Sampling was done during the summer of 2018 when water and fish samples were collected from five different locations of El-Manzala Lake. It was found that the studied locations recorded hazardous concentrations of polyaromatic hydrocarbons (PAHs) that may cause significant defects to aquatic organisms except in the reference location and affect the expression of CYP19a&b genes. The relative gene expressions of CYP19a in the ovary and the testis were measured and recorded in positive ranges, but revealed the controversial expression pattern of CYP19b gene in the brain tissues. Our results revealed that PAHs discharges at El-Manzala Lake are correlated with the gene expression of CYP19 genes. The current findings suggested a correlation between biomarkers response and wastewater exposure as stressors. Besides, the assessed multiple general health indicators give prospective insights for Nile tilapia adaptive pattern and monitoring of pollution of freshwater ecosystems. [ABSTRACT FROM AUTHOR]

The present study is the first concerning commercial trammel net selectivity in El-Salam Canal. Selection ogives were estimated using Holt's method (1957) for both Oreochromis niloticus and Oreochromis aureus. L50 retention lengths of both species were estimated as 11.1-cm and 11.5-cm corresponding to the inner layer-mesh bar (2.15-cm) for the two species, respectively. With increasing the mesh bar to 2.65cm, L50 increased to reach 14.2 and 13.0cm in respective order for both species. The mean selection length calculated by Holt's method for Oreochromis niloticus increased from 11.97-cm (opposed to the smaller mesh bar) to 14.76-cm (opposed to the larger mesh bar). The same trend for O. aureus, the mean selection length increased from 11.64-cm to 14.34-cm in respective order also. Therefore, it's recommended to use larger inner layer mesh bar length of 3-cm at least to gain extra weight and give more reproduction opportunities. [ABSTRACT FROM AUTHOR]

The genus Aeromonas has been recognised as an important pathogenic species in aquaculture that causes motile Aeromonas septicaemia (MAS). This study was conducted on 224 samples were collected from tilapia (n = 56), water (n = 56), the sediment of the fish farm soil (n= 56), and stool of patients suffering from gastroenteritis (n = 56). A total of 87 positive Aeromonas spp. isolates were recovered from 224 samples with an overall prevalence of 38.8%, distribution of them based on their sources was 55.3% (31/56) from diseased tilapia fish, 21.4% (12/56) from water, 30.3% (17/56) from soil, and 48.2% (27/56) from stool swab of diarrheic patients. The Aeromonas species showed different level of antibiotics susceptibility based on the inhibition zone observed around the antibiotics disc. Aeromonas spp. were all resistant to ampicillin, amoxacillin and pencillin g with an average zone of inhibition of 10mm, 8mm and 9mm respectively but highly susceptible to moxfloxacin, norfloxacin and ciprofloxacin with an average zone of inhibition of 21 mm, 17 mm and 24 mm respectively while they were randomly susceptible to cefotaxime, gentamycin and streptomycin. Therefore, moxfloxacin, norfloxacin and ciprofloxacin are effective drugs that can be used in the treatment of Aeromonas associated infections. PCR using 16S rRNA was used to confirm A. hydrophila positive isolates. Due to Aeromonas is a hard stretched and elastic organism there is a need for antibiotic sensetivity test before the treatment since some strains of the Aeromonas species were randomly susceptible to the some of the antibiotics. PCR using 16S rRNA was used to confirm A. hydrophila positive isolates. [ABSTRACT FROM AUTHOR]

This study reports the outcomes of a survey on the use of additives in 120 Egyptian grow-out farms carried out between 2018 and 2019. The survey focused on farms rearing Nile tilapia (Oreochromis niloticus) in the biggest tilapia farming region in Egypt (Kafr El-Sheikh). Results were analysed to explore whether any type of additive was used, whether they were feed-or water-based and the frequency of use. A range of farm characteristics and farm management practices were used as independent variables to explain observed additive use patterns reported by farmers. The survey also gathered production data to explore a potential relationship between the use of additives and total marketable yield or mortality. The results of this survey display very low use of any sort of additive in this tilapia farming region (<33% of respondents) which is likely representative of practices in other production regions throughout the country. The most commonly reported additive classes were antibiotics, disinfectants and probiotics with the former two primarily used for treating disease after detecting mortalities in the ponds. Feed-based additives were used more frequently than water-based ones amongst which antibiotics were the most prevalent. There was no association between the use of additives and reported fish survival or total farm production. However, this is likely constrained by the small number of farms found to be using additives relative to the overall number of surveyed farms. Given the increasing trend in the use of additives in small-scale aquaculture, further efforts are needed to establish their cost-benefit and to promote their correct use where appropriate. Moreover, clear regulations are needed to prevent misuse of antimicrobials and minimise potential food safety concerns. [ABSTRACT FROM AUTHOR]