Silymarin conserves the efficacy of quinolone and sulfonamide in Nile tilapia (Oreochromis niloticus) subjected to aflatoxicosis and Streptococcus agalactiae infection Nourhan A. Haggag, Mohamed Elbadawy, Ashraf ElKomy, Ahmed H. Sherif Scientific Reports, 2026 Aflatoxins (AFB) are adventitious plant toxins that act as immunosuppressants. Experimental Nile tilapia were divided into eight groups: AFB0 (control, uncontaminated diet), AFB50 (50 ppbAFB 1 ), AFB100 (100 ppbAFB 1 ), AFB150 (150 ppbAFB 1 ), AFB0 + Sil (0 ppbAFB 1 +Sil), AFB50 + Sil (50 ppbAFB 1 +Sil), AFB100 + Sil (100 ppbAFB 1 +Sil), and AFB150 + Sil (150 ppbAFB 1 +Sil). The AFB 1 -residues in fish liver (AFB0, AFB50, AFB100, and AFB150) were 0.34, 0.54, and 0.82 ppb, respectively, while traces were recorded in muscles. Sil-supplemented fish had lower residues than other contaminated groups, which were still higher than AFB0. The gene expression of GPx , SOD , IL-1β , and TNF-α was significantly and linearly decreased with increasing aflatoxin levels, whereas Sil-supplementation (AFB50 + Sil) resulted in a high and significant increase of 3.86, 5.37, and 7.85 fold-change, respectively, compared with the fish groups and the control. While, CAT expression increased in response to a low aflatoxin level (AFB50; 2.17-fold-change), it decreased linearly with increasing aflatoxin level. Moreover, IL-10 expression was significantly higher in fish of AFB100 and AFB150, with 8.7- and 8.85-fold changes, respectively, compared to the control. Significant declines in immunoglobulin (Ig)M-2 and insulin-like growth factor (IGF) gene expression were observed in fish receiving AFB 1 -contaminated diets and Sil could enhance the expression. Innate immunity of the experimental fish was assessed by measuring the following parameters; serum antibacterial activity (SAB), oxidative burst activity (OBA), phagocytic activity (PA), phagocytic index (PI), and lysozyme (LYZ) as well as by challenge with Streptococcus agalactiae . Nile tilapia fed AFB 1 -contaminated diets showed immune-antioxidant suppressive status, indicating compromised health and a lowered survival rate (SR%) during bacterial challenge and antibiotic treatment Sil-supplementation could improve SR%.
Silymarin enhances the performance of Nile tilapia fed an aflatoxin B1-contaminated diet Nourhan A. Haggag, Mohamed Elbadawy, Ashraf ElKomy, Ahmed H. Sherif Aquaculture International, 2025 Intensive aquaculture consumes high amounts of plant-based feed. Unfortunately, this practice increases the risk of aflatoxin B 1 (AFB 1 ) accumulation in fish tissues, impacting their physiological status. The ability of dietary silymarin to mitigate dietary AFB 1 (122.4 ppb) was investigated for 84 days in eight experimental groups: Sil-0 (control, uncontaminated feed), Sil-0.5 (0.5 g/kg), Sil-1 (1 g/kg), Sil-1.5 (1.5 mg/kg), AFB 1 +Sil-0, AFB 1 +Sil-0.5, AFB 1 +Sil-1, and AFB 1 +Sil-1.5. AFB 1 residue in the fish liver of AFB 1 +Sil-0 was 0.86 ppb, while dietary silymarin decreased the residues in the hepatic tissues of AFB 1 +Sil-0.5, AFB 1 +Sil-1, and AFB 1 +Sil-1.5 to 0.64, 0.37, and 0.22 ppb, respectively. Meanwhile, trace residues were found in muscle tissues regardless of AFB 1 levels. Results showed that dietary AFB 1 caused a decline in growth performance and blood indices (RBCs, WBCs, Hb, PCV, MCV, MCH, and MCHC) as well as a decline in lipid profile and serum proteins TP, ALB, and GLO, indicating malnutrition of Nile tilapia. The liver enzymes AST and ALT were up-regulated in response to dietary AFB 1 . Regarding Streptococcus agalactiae infection, fish that received AFB 1 showed high mortality (MR%) and re-isolation (RI%) rates. It also resulted in a weak response to oxytetracycline (OTC) treatment, with high MR%. These effects partially subsided after receiving dietary silymarin, especially Sil-1 (1 g/kg). It is recommended that AFB 1 residues be monitored periodically before oxytetracycline treatment in case of bacterial infection.
The role of Moringa oleifera in enhancing fish performance and health: a comprehensive review of sustainable aquaculture applications Sohair Y. Saleh, Nehal A. Younis, Ahmed H. Sherif, Howyda G. Gaber Veterinary Research Communications, 2025 This comprehensive review examines the versatile applications and effects of Moringa oleifera across multiple fish species in aquaculture systems amid growing challenges of rising feed costs and antimicrobial resistance. M. oleifera, commonly called the Miracle tree, contains an exceptional nutritional profile with high protein content (22.99–29.36% dry weight), complete profiles of essential amino acids, and remarkably elevated levels of vitamins and minerals. Its bioactive profile includes substantial quantities of polyphenols, flavonoids, alkaloids (niazimicin, niaziminin, β-sitosterol), and glucosinolates that collectively enhance fish health and performance. Recent studies across multiple fish species demonstrate variable optimal inclusion rates (5–30%) with specific growth rates increasing 15–35% and feed conversion ratios improving 10–25% compared to controls. Physiological benefits include enhanced digestive enzyme activity, improved liver and kidney functions, and reduced cortisol levels during environmental stress. Immunologically, M. oleifera supplementation significantly increases lysozyme activity, complement C3, total IgM levels, and pro-inflammatory cytokine expression (TNFα, IL1-β, IL-6), strengthening resistance against major aquaculture pathogens including Aeromonas hydrophila, Pseudomonas aeruginosa, and Vibrio species. Challenge studies demonstrate relative percent survival improvements ranging from 48 to 73% against virulent pathogens. Haematological improvements include increased erythrocyte counts, higher haemoglobin levels at moderate inclusion rates, and beneficial effects on glucose metabolism and lipid profiles. Moringa seeds are highly effective natural water clarifiers, removing 95–99% of turbidity through cationic proteins that act as coagulants. However, their antinutritional compounds (tannins, phytates, saponins, oxalates) can harm fish at elevated levels, requiring careful dosage monitoring in aquaculture applications. This review synthesizes current evidence, identifies optimal application strategies, and provides direction for future research to maximize Moringa’s potential as a sustainable, cost-effective resource for enhancing productivity, fish health, and environmental sustainability in modern aquaculture systems.
Presence of virulent Edwardsiella tarda in farmed nile tilapia and striped catfish Lamiaa A. Okasha, Enas A. H. Farag, Rasha M. H. Sayed-ElAhl, Ahmed H. Sherif BMC Microbiology, 2025 The production of striped catfish (Pangasianodon hypothalamus) has increased worldwide; recently, it was farmed with Nile tilapia in polyculture farms. Polyculture systems and water temperature (25℃ and 33℃) could affect Edwardsiella tarda infection, antibiotic efficacy, and residues. Moribund fishes were collected from three Farms 1–3: Farm 1 (monoculture, Nile tilapia), Farm 2 (monoculture, striped catfish), and Farm 3 (polyculture). Four E. tarda, LAMSH1, and LAMAH2-4 were isolated, whereas LAMAH3 was isolated from both fish spp., where striped catfish were highly susceptible to infection. The obtained E. tarda, which was isolated from striped catfish, has a significantly lower LD50 than those retrieved from Nile tilapia, and co-infection occurred only in striped catfish on Farm 3. The infection was screened and confirmed by gyrB1 gene presence while detecting the cds1, pvsA, and qseC genes indicated virulence. All isolates were sensitive to ciprofloxacin and florfenicol but showed resistance to a high number of other antibiotics, resulting in high multi-drug resistant (MDR) indices exceeding 0.2, except for strain LAMAH4, which had an index of 0.18. Analyses of farms water revealed high ammonia compounds total ammonia nitrogen (TAN), unionized ammonia (NH3), nitrite (NO2), and nitrate (NO3) in Farm 2 (monoculture, striped catfish), and the recorded significantly higher concentrations were 2.75, 0.29, 0.24, and 2.01 mg/L, respectively, which were compared with Farm 1 and Farm 3. In the indoor experiment, at high water temperatures (33 °C), Nile tilapia and striped catfish had a high mortality rate and re-isolation of E. tarda (10–20%) compared to those exposed to low water temperatures (25 °C). These observations were concurrent with low antibiotic residues in their hepatic tissues. Despite water temperature, Nile tilapia showed higher ciprofloxacin residues than striped catfish. The study concluded that striped catfish are more susceptible to the bacteria E. tarda compared to Nile tilapia, particularly in polyculture farms, which resulted in a higher infection rate. Both Nile tilapia and striped catfish exposed to elevated water temperatures exhibited increased vulnerability to bacterial infections. Additionally, these fish showed a high re-isolation rate of E. tarda while having low ciprofloxacin residues in their hepatic tissues.
Salinity-dependent vulnerability of whiteleg shrimp (Litopenaeus vannamei) to Vibrio parahaemolyticus: growth performance and antioxidant response Lamiaa A. Okasha, Enas A. H. Farag, Rasha M. H. Sayed-ElAhl, El-Sayed H. Eissa, Ahmed H. Sherif Aquaculture International, 2025 Whiteleg shrimp (Litopenaeus vannamei) became one of the most cultured crustacea in marine farms in North Egypt. The bacteriological examination of two shrimp farms (water salinity 4.28 and 28.5 g/L) that exhibited high mortality rates revealed the causative agents, which were three Vibrioparahaemolyticus strains VHLA1-3. They were identified by detecting three genes: integral membrane protein (toxR) and haemolysin genes (tdh and trh). The strains were multidrug-resistant and were sensitive to ciprofloxacin and florfenicol; also, their median lethal doses (LD50) were 3.78 × 105, 1.99 × 105, and 1.95 × 105 CFU/mL, respectively. In the experiment, 180 healthy shrimp (5.3 ± 0.03 g, body weight) were reared in three different water salinities 7, 35, and 50 g/L for 8 weeks and then were challenged with LD50 of the isolates VHLA1-3. At salinity of 50 g/L, shrimp experimentally infected with VHLA1, VHLA2, and VHLA3 showed a higher MR of 60%, 80%, and 80% compared to those of 7 and 35 g/L; florfenicol treatment resulted in mortality rate ranged between 10 and 20% regardless water salinity. Bacterial re-isolation (RI%) was 100% in challenged-untreated shrimp, whereas RI% was decreased after florfenicol treatment by 20%, 30 to 40%, and 0% at salinity of 7, 35, and 50 g/L, respectively. Experimental shrimp reared in high salinity (50 g/L) showed significantly higher final weight (15.6 g), specific growth rate (1.54%/fish/day), and low FCR compared to those of low salinity water (35 and 7 g/L). At salinity of 50 g/L, the expression of catalase CAT and superoxide dismutase SOD genes was significantly higher compared to those of low salinity, while the heat shock protein Hsp70 expression was significantly raised in 50 g/L, followed by 7 g/L then 35 g/L in the hepatopancreas of shrimp. It was obvious that V. parahaemolyticus was the causative agent in shrimp mortality, with different patterns of virulent genes. Water salinity was the control factor in antioxidant status and V. parahaemolyticus infection. Shrimp reared at salinity extremities, 7 and 50 g/L, exhibited high mortality and bacterial re-isolation. So, florfenicol treatment is recommended in V. parahaemolyticus infection, and salinity extremities (7 and 50 g/L) should be avoided during rearing whiteleg shrimp.
Aeromonas veronii infection in cultured Oreochromis niloticus: prevalence, molecular and histopathological characterization correlated to water physicochemical characteristics, with the protective autochthonous probiotic Amr Fadel, Mahmoud A. Mahmoud, Mohamed Abdelsalam, El-Sayed Hemdan Eissa, Ahmed H. Sherif Aquaculture International, 2025 This study characterized the bacterial pathogen associated with summer mortality in cultured Nile tilapia (Oreochromis niloticus) between June and August 2024 across two different farms. As well as, the autochthonous probiotic was isolated as a preventive strategy. Phenotypic characteristics identified Aeromonas veronii and confirmed by molecular sequencing of the gyrB gene. Total prevalence was higher in farm 1 (65.19%) than in farm 2 (51.11%), with respective mortality rates of 38.84% and 25.25%. Prevalence rates peaked in August, which was correlated significantly (P ≤ 0.05) with elevated water temperature, pH, ammonia, and salinity. Clinical signs included erratic swimming, skin hemorrhages, and corneal opacity, with necropsy including ascitic fluids, friable liver, and splenomegaly. Challenge assay confirmed LD50 of 2.7 × 107 CFU/mL A. veronii and 66.67% cumulative mortality. Histopathological alterations showed intermuscular edema, glomerular atrophy of the kidneys, vacuolar degeneration of the liver, spleen necrosis, and hemosiderosis of intestinal tissues. A. veronii showed resistance to ampicillin, tigecycline, fosfomycin, and sulfamethoxazole-trimethoprim. To control Aeromonas infection, 18 autochthonous probiotic isolates were obtained from the healthy O. niloticus gut and identified as Bacillus paralicheniformis through phenotypic analysis and 16S rRNA gene sequencing. These probiotic isolates demonstrated strong antagonistic activity against the pathogenic A. veronii, ecto-enzymatic producing activities, and high bile salt tolerance. After comprehensive screening, seven Bacillus strains met safety criteria, exhibiting high sensitivity to antimicrobials, non-hemolytic activity, and non-pathogenic in the challenge test. This study confirms A. veronii as the causative agent of tilapia summer mortality and presents promising autochthonous probiotics for preventive strategies in aquaculture.
The nanocomposite of chitosan-vitamin C modulates the expression of immune and antioxidant-related genes in Nile tilapia stressed with lead (Pb) Ahmed H. Sherif, Amr Fadel, Enas A. Kasem, Magdy E. Mahfouz, Elsayed A. Eldessouki, et al. Aquaculture International, 2025 Fish cultivated in a polluted environment usually face complicated disease cases. Pollution is an evitable event in aquaculture that weakens surface immunity, delaying and lowering the immune responses of aquatic animals. In an indoor experiment, Nile tilapia were reared in water polluted with lead (Pb) at a concentration of 51 µg/l for 8 weeks. A trial was conducted to mitigate the immunosuppression using pre-acclimatized Nile tilapia that were subdivided into six groups in which the exposed fish treated with nanocomposite (chitosan-vitamin C-protected nanoparticles (CVC-NPs)) consisted of 1 g of chitosan nanoparticles containing 400 mg vitamin C/kg fish and 200 mg vitamin C/kg fish feed for 1 week. Fish exposed to Pb pollution were immunocompromised as gene expression of immune-related cytokine and antioxidant enzymes significantly declined. Innate immunity was drastically impacted as OBA, phagocytosis and serum antibacterial activity (SAA) showed low values compared to the control fish; meanwhile, exposed fish was challenged against Streptococcus agalactiae and showed a high mortality rate (MR%). Dietary nanocomposite could restore normal immune status, and supplemented fish achieved low MR% with significantly high gene expression of proinflammatory cytokines. It was concluded that adding 200 mg of CVC-NPs/kg fish feed for 1 week could effectively protect Nile tilapia from S. agalactiae, having superiority over the high dose of 400 mg of CVC-NPs.
