Shaalan, M., H. H. Mahboub, A. H. Abdelgawad, A. A. Abdelwarith, E. M. Younis, A. A. Elnegiry, A. W. Basher, W. El-Houseiny, S. M. Shawky, S. H. Orabi, et al., "Dietary tea tree (Melaleucae Aetheroleum) oil fortifies growth, biochemical, immune-antioxidant trait, gene function, tissue reaction, and Aeromonas sobria resistance in Nile tilapia (Oreochromis niloticus).", BMC veterinary research, vol. 21, issue 1, pp. 1, 2025. Abstract

The current study had aimed to assess the long-term dietary supplementation with Melaleucae aetheroleum, tea tree essential oil (TTO). The impact on growth performance, biochemical indices, immune function, oxidant/antioxidant activity, gene expression, histopathology, and resistance against Aeromonas sobria in Nile tilapia (Oreochromis niloticus) was investigated. Four groups (with five replicates; G1 (control group, G2, G3, and G4) of Nile tilapia received diets enriched with TTO (doses of 0.0, 0.5, 1.0, and 2.0 mL/kg diet) for 60 days, then fish were challenged by A. sobria. Outcomes indicated an extensive elevation in growth metrics (final body weight, weight gain, SGR, feed intake and fish body protein). Similarly, the total blood protein, albumin, total globulin levels, Serum complement-3 levels, lysozyme activity, immunoglobulin M (IgM), nitric oxide, and phagocytic activity were significantly enhanced in all treatments, notably in the 2.0 mL TTO/kg fed groups compared to the control. Lower levels of urea, creatinine, AST, ALP, ALT, cortisol, glucose, triglycerides, cholesterol and body crude lipids were observed in the fish that were fed a 2.0 mL TTO/kg diet. Supplementing TTO at 2.0-mL /kg diet revealed the best results for elevating CAT, SOD, and GSH activities plus declining MDA value in hepatic homogenate. Additionally, dietary 2.0-mL TTO/kg showed the best outcomes for the intestinal morphometry plus maintaining the histological picture in spleen and liver. Concurrently, fish that were fed a 2.0 mL TTO/kg diet exhibited a substantial upregulation of TNF-α, IL-1β, IL-10, TFG-β, IFN-γ and BCL-2 genes in the liver, while, caspase-3, and BAX were downregulated. Furthermore, TTO-enriched diets enhanced the relative percentage survival post-A. sobria challenge plus enhanced the clinical picture in a dose-dependent manner. Taken together, the findings revealed that long-term exposure to dietary TTO fortified the physiological performance, oxidant/anti-oxidant stability, immune function, gene expression, histological picture, and resistance of Nile tilapia against A. sobria.

Mahboub, H. H., A. A. N. Rahman, S. T. Elazab, A. A. Abdelwarith, E. M. Younis, M. Shaalan, E. K. Aziz, M. S. Sobh, M. Yousefi, S. H. Ismail, et al., "Nano-chitosan hydrogel alleviates Candida albicans-induced health alterations in Nile tilapia (Oreochromis niloticus): antioxidant response, neuro-behaviors, hepato-renal functions, and histopathological investigation.", BMC veterinary research, vol. 21, issue 1, pp. 159, 2025. Abstract

BACKGROUND: Candida albicans infection induces economic losses in aquaculture practices. Currently, the success of the nanotechnology field has gained more consideration in the aquaculture sector as it bestows favorable impacts in remedies in comparison to traditional practices.

OBJECTIVE: The present study was conducted to assess the role of nano chitosan gel (NCG) exposure via water in managing the deteriorating impacts triggered by C. albicans in Nile tilapia, Oreochromis niloticus. Hepato-renal function, behavioral and stress response, neurological function, hepatic antioxidant/oxidant status, and histopathological architectures were investigated.

METHODS: A total of 160 fish (average weight: 50.00 ± 6.30 g) were randomly assigned to four groups, each with four replicates: control, NCG, C. albicans, and NCG + C. albicans. The NCG was applied as bath treatment at a concentration of 75 µg/L for ten days.

RESULTS: The outcomes demonstrated that the C. albicans challenged fish exhibited obvious behavioral alterations including loss of equilibrium, surfacing, abnormal swimming and movement, and aggression. Infection with C. albicans caused an elevation in hepato-renal biomarkers (alanine and aspartate aminotransferases, alkaline phosphatase, urea, and creatinine), stress-related indices (glucose, cortisol, nor-epinephrine, and 8-hydroxy-2-deoxyguanosine), and lipid peroxides (malondialdehyde). Moreover, it caused a noticeable decline in the hepatic antioxidant indices (total antioxidant capacity and reduced glutathione content) and acetylcholinesterase activity. The hepatic, renal, and brain architectures were severely damaged by the C. albicans challenge, exhibiting significant fatty changes, necrosis, vacuolation, and congestion. Remarkably, the aqueous application of NCG in the C. albicans-challenged fish ameliorated all the aforementioned biomarkers and facilitated the regeneration of histopathological changes.

CONCLUSION: Overall, the application of NCG in the aquatic environment is an effective tool for managing C. albicans infection in Nile tilapia. Moreover, it can be utilized in combating stress conditions in the aquaculture sector.

Mahboub, H. H., A. A. N. Rahman, S. T. Elazab, A. A. Abdelwarith, E. M. Younis, M. Shaalan, E. K. Aziz, M. S. Sobh, M. Yousefi, S. H. Ismail, et al., "Nano-chitosan hydrogel alleviates Candida albicans-induced health alterations in Nile tilapia (Oreochromis niloticus): antioxidant response, neuro-behaviors, hepato-renal functions, and histopathological investigation.", BMC veterinary research, vol. 21, issue 1, pp. 159, 2025. Abstract

BACKGROUND: Candida albicans infection induces economic losses in aquaculture practices. Currently, the success of the nanotechnology field has gained more consideration in the aquaculture sector as it bestows favorable impacts in remedies in comparison to traditional practices.

OBJECTIVE: The present study was conducted to assess the role of nano chitosan gel (NCG) exposure via water in managing the deteriorating impacts triggered by C. albicans in Nile tilapia, Oreochromis niloticus. Hepato-renal function, behavioral and stress response, neurological function, hepatic antioxidant/oxidant status, and histopathological architectures were investigated.

METHODS: A total of 160 fish (average weight: 50.00 ± 6.30 g) were randomly assigned to four groups, each with four replicates: control, NCG, C. albicans, and NCG + C. albicans. The NCG was applied as bath treatment at a concentration of 75 µg/L for ten days.

RESULTS: The outcomes demonstrated that the C. albicans challenged fish exhibited obvious behavioral alterations including loss of equilibrium, surfacing, abnormal swimming and movement, and aggression. Infection with C. albicans caused an elevation in hepato-renal biomarkers (alanine and aspartate aminotransferases, alkaline phosphatase, urea, and creatinine), stress-related indices (glucose, cortisol, nor-epinephrine, and 8-hydroxy-2-deoxyguanosine), and lipid peroxides (malondialdehyde). Moreover, it caused a noticeable decline in the hepatic antioxidant indices (total antioxidant capacity and reduced glutathione content) and acetylcholinesterase activity. The hepatic, renal, and brain architectures were severely damaged by the C. albicans challenge, exhibiting significant fatty changes, necrosis, vacuolation, and congestion. Remarkably, the aqueous application of NCG in the C. albicans-challenged fish ameliorated all the aforementioned biomarkers and facilitated the regeneration of histopathological changes.

CONCLUSION: Overall, the application of NCG in the aquatic environment is an effective tool for managing C. albicans infection in Nile tilapia. Moreover, it can be utilized in combating stress conditions in the aquaculture sector.

Mahboub, H. H., A. A. N. Rahman, S. T. Elazab, A. A. Abdelwarith, E. M. Younis, M. Shaalan, E. K. Aziz, M. S. Sobh, M. Yousefi, S. H. Ismail, et al., "Nano-chitosan hydrogel alleviates Candida albicans-induced health alterations in Nile tilapia (Oreochromis niloticus): antioxidant response, neuro-behaviors, hepato-renal functions, and histopathological investigation.", BMC veterinary research, vol. 21, issue 1, pp. 159, 2025. Abstract

BACKGROUND: Candida albicans infection induces economic losses in aquaculture practices. Currently, the success of the nanotechnology field has gained more consideration in the aquaculture sector as it bestows favorable impacts in remedies in comparison to traditional practices.

OBJECTIVE: The present study was conducted to assess the role of nano chitosan gel (NCG) exposure via water in managing the deteriorating impacts triggered by C. albicans in Nile tilapia, Oreochromis niloticus. Hepato-renal function, behavioral and stress response, neurological function, hepatic antioxidant/oxidant status, and histopathological architectures were investigated.

METHODS: A total of 160 fish (average weight: 50.00 ± 6.30 g) were randomly assigned to four groups, each with four replicates: control, NCG, C. albicans, and NCG + C. albicans. The NCG was applied as bath treatment at a concentration of 75 µg/L for ten days.

RESULTS: The outcomes demonstrated that the C. albicans challenged fish exhibited obvious behavioral alterations including loss of equilibrium, surfacing, abnormal swimming and movement, and aggression. Infection with C. albicans caused an elevation in hepato-renal biomarkers (alanine and aspartate aminotransferases, alkaline phosphatase, urea, and creatinine), stress-related indices (glucose, cortisol, nor-epinephrine, and 8-hydroxy-2-deoxyguanosine), and lipid peroxides (malondialdehyde). Moreover, it caused a noticeable decline in the hepatic antioxidant indices (total antioxidant capacity and reduced glutathione content) and acetylcholinesterase activity. The hepatic, renal, and brain architectures were severely damaged by the C. albicans challenge, exhibiting significant fatty changes, necrosis, vacuolation, and congestion. Remarkably, the aqueous application of NCG in the C. albicans-challenged fish ameliorated all the aforementioned biomarkers and facilitated the regeneration of histopathological changes.

CONCLUSION: Overall, the application of NCG in the aquatic environment is an effective tool for managing C. albicans infection in Nile tilapia. Moreover, it can be utilized in combating stress conditions in the aquaculture sector.

Doszpoly, A., M. Shaalan, and M. El-Matbouli, "Silver Nanoparticles Proved to Be Efficient Antivirals In Vitro against Three Highly Pathogenic Fish Viruses.", Viruses, vol. 15, issue 8, 2023. Abstract

The efficacy of silver nanoparticles (AgNPs) was tested in vitro against three different fish viruses, causing significant economic damage in aquaculture. These viruses were the spring viraemia of carp virus (SVCV), European catfish virus (ECV), and Ictalurid herpesvirus 2 (IcHV-2). The safe concentration of AgNPs that did not cause cytotoxic effects in EPC cells proved to be 25 ng/mL. This dose of AgNPs decreased significantly (5-330×) the viral load of all three viruses in three different types of treatments (virus pre-treatment, cell pre-treatment, and cell post-treatment with the AgNPs). In a higher concentration, the AgNPs proved to be efficient against ECV and IcHV-2 even in a delayed post-cell-treatment experiment (AgNP treatment was applied 24 h after the virus inoculation). These first in vitro results against three devastating fish viruses are encouraging to continue the study of the applicability of AgNPs in aquaculture in the future.

EL-NAHASS, E. L. - S. H. A. Y. M. A. A., M. K. Abdelhamid, A. Ali, A. A. Shalaby, and M. Shaalan, "Pathological assessment and tissue tropism of two different Egyptian infectious bronchitis strains.", Virusdisease, vol. 34, issue 3, pp. 410-420, 2023. Abstract

Avian infectious bronchitis is one of the most common viral infections in chickens affecting all ages. The tropism of infectious bronchitis virus (IBV) strains became broader and more variable posing major implications for the effective control of IBV infection. In this study, two IBV viruses representing classic and variant strains were inoculated intranasally into day-old SPF chicks (10 EID/0.2 ml/bird). Clinical signs were observed for 15 days post-infection (DPI). Five chicks from each group were euthanized at 2, 4, 6, 8, 10, 12, and 15 DPI for histopathology and virus antigen detection by IHC and quantitative rRT-PCR. Results revealed that both classic and variant IBV strains induced mild clinical signs with no mortalities and fewer various histopathological lesions in infected SPF chickens. Although the viruses were detected by rRT-PCR up to 12 DPI, the affected tissues showed regeneration after 10 DPI with IHC revealing no IBV antigen. In summary, no differences were found in the behaviour of both IBV isolates in chickens. The broad tissue tropism for both IBV strains as indicated by viral antigen detection in various organs with no clinical or gross lesion suggest that the main cause of death in IBV infection under field conditions occurs as a result of complication with secondary infections rather single IBV infection. Due to positive immunostaining in the bursa, it is thought that IBV infection has immunosuppressive consequences, hence further study is required to validate this impact.

Saleh, M., E. Essawy, M. Shaalan, S. Osman, F. Ahmed, and M. El-Matbouli, "Therapeutic Intervention with Dietary Chitosan Nanoparticles Alleviates Fish Pathological and Molecular Systemic Inflammatory Responses against Infections.", Marine drugs, vol. 20, issue 7, 2022. Abstract

Marine bio-sourced chitosan nanoparticles (CSNP) are antimicrobial and immunomodulatory agents beneficial for fish medicine. Herein, dietary CSNP was investigated for the amelioration of the systemic inflammatory responses of an induced fish model. One hundred and forty-four rainbow trout were assigned to one pathogen-free and non-supplemented group (negative control), and three challenged groups: non-supplemented (positive control), CSNP-preventive, and CSNP-therapeutic. After a feeding experiment extended for 21 days, the organosomatic indices (OSI) and molecular aspects were assessed. After a challenge experiment extended for further 28 days, CSNP-therapeutic intervention was assessed on fish survival and systemic inflammatory responses on pathology, histo-morphology, and molecular aspects. With CSNP administration, OSI nonsignificantly decreased and the relative expression of targeted inflammatory-mediator genes was significantly increased. The CSNP-therapeutic fish showed an RPS of 80% as compared to the positive control group, and CSNP-therapeutic administration retained the highest gene expression augmentation up to 28 days after the challenge. Notably, the splenic reticulin fibers framework of the CSNP-therapeutic group retained the highest integrity among the groups during the infection. After recovery, reticulin fibers density in the CSNP-therapeutic samples was significantly higher than in the negative control group, which indicates high innate immunity. Thus, CSNP showed promising biotherapeutic features enhancing fish resistance against infections.

Marouf, S., X. Li, H. M. Salem, Z. S. Ahmed, S. M. Nader, M. Shaalan, F. H. Awad, H. Zhou, and T. Cheang, "Molecular detection of multidrug-resistant Pseudomonas aeruginosa of different avian sources with pathogenicity testing and in vitro evaluation of antibacterial efficacy of silver nanoparticles against multidrug-resistant P. aeruginosa.", Poultry science, vol. 102, issue 10, pp. 102995, 2023. Abstract

Pseudomonas aeruginosa (P. aeruginosa) is a serious zoonotic pathogen threaten the poultry industry causing severe economic losses therefor, this study aimed to isolation, phenotypic, molecular identification of P. aeruginosa from different avian sources (chickens, turkey, pigeons, table eggs, and dead in shell chicken embryos), from different Egyptian governorates (Giza, Qalubia, Beheira, El-Minya, and Al-Sharqia) with applying of antibiotic sensitivity test on all P. aeruginosa isolates. Highly resistant isolates (n = 49) were subjected to molecular identification of P. aeruginosa with detection of resistant genes including carbapenemase-encoding genes blaKPC, blaOXA-48, and blaNDM. On the base of molecular results, a highly resistant P. aeruginosa strain was tested for its pathogenicity on day old specific pathogen free (SPF) chicks. Also, in vitro experiment was adopted to evaluate the efficacy of silver nanoparticles (Ag-NPs) against highly antibiotic-resistant P. aeruginosa strains. The overall isolation percentage was from all examined samples were 36.2% (571/1,576) representing 45.2% (532/1,176) from different birds' tissues and 39/400 (9.7%) from total egg samples. Some of isolated strains showed multidrug resistance (MDR) against kanamycin, amoxicillin, amoxicillin-clavulanic acid, neomycin, chloramphenicol, vancomycin, cefotaxime clavulanic acid, lincomycin-spectinomycin, co-trimoxazole, cefoxitin, gentamycin, and doxycycline. These MDR strains were also molecularly positive for ESBL and carbapenemase-encoding genes. MDR strain showed high pathogenicity with histopathological alterations in different organs in challenged birds. Main histopathological lesions were necrosis of hepatocytes, renal tubular epithelium, and heart muscle bundles. The MDR strain showed in vitro sensitivity to Ag-NPs. In conclusion, MDR P. aeruginosa is a serious pathogen causing high morbidity, mortality, and pathological tissue alterations. Ag NPs revealed a promising in vitro antimicrobial sensitivity against MDR P. aeruginosa and further in vivo studies were recommended.

Ahmed, N. H. M., A. Ghallab, M. Shaalan, M. Saied, and E. S. Mohammed, "First molecular identification and phylogenetic illustration of Sarcocystis species infection in Red Sea shortfin mako shark (Isurus oxyrinchus Rafinesque, 1810).", BMC veterinary research, vol. 20, issue 1, pp. 104, 2024. Abstract

BACKGROUND: members of the genus Sarcocystis are intracellular obligate protozoan parasites classified within the phylum Apicomplexa and have an obligate heteroxenous life cycle involving two hosts. A more comprehensive understanding of the prevalence and geographic range of different Sarcocystis species in marine ecosystems is needed globally and nationally. Hence, the objective of this study was to document the incidence of Sarcocystis infection in sharks within the aquarium ecosystem of Egypt and to identify the species through the characterization of the SSU rDNA gene.

METHODS: All organs of the mako shark specimen underwent macroscopic screening to detect the existence of a Sarcocystis cyst. Ten cysts were collected from the intestine and processed separately to extract the genomic DNA. The polymerase chain reaction (PCR) was accomplished by amplifying a specific 18S ribosomal RNA (rRNA) gene fragment. Subsequently, the resulting amplicons were subjected to purification and sequencing processes.

RESULTS: Macroscopic examination of the mako shark intestinal wall sample revealed the presence of Sarcocystis cysts of various sizes and shapes, and sequencing of the amplicons from Sarcocystis DNA revealed a 100% nucleotide identity with the sequence of Sarcocystis tenella recorded from sheep in Iran; The mako shark sequence has been deposited in the GeneBank with the accession number OQ721979. This study presents the first scientific evidence demonstrating the presence of the Sarcocystis parasite in sharks, thereby documenting this specific marine species as a novel intermediate host in the Sarcocystis life cycle.

CONCLUSIONS: This is the first identification of Sarcocystis infection in sharks, and we anticipate it will be an essential study for future screenings and establishing effective management measures for this disease in aquatic ecosystems.

Marouf, S., X. Li, H. M. Salem, Z. S. Ahmed, S. M. Nader, M. Shaalan, F. H. Awad, H. Zhou, and T. Cheang, "Molecular detection of multidrug-resistant Pseudomonas aeruginosa of different avian sources with pathogenicity testing and in vitro evaluation of antibacterial efficacy of silver nanoparticles against multidrug-resistant P. aeruginosa.", Poultry science, vol. 102, issue 10, pp. 102995, 2023. Abstract

Pseudomonas aeruginosa (P. aeruginosa) is a serious zoonotic pathogen threaten the poultry industry causing severe economic losses therefor, this study aimed to isolation, phenotypic, molecular identification of P. aeruginosa from different avian sources (chickens, turkey, pigeons, table eggs, and dead in shell chicken embryos), from different Egyptian governorates (Giza, Qalubia, Beheira, El-Minya, and Al-Sharqia) with applying of antibiotic sensitivity test on all P. aeruginosa isolates. Highly resistant isolates (n = 49) were subjected to molecular identification of P. aeruginosa with detection of resistant genes including carbapenemase-encoding genes blaKPC, blaOXA-48, and blaNDM. On the base of molecular results, a highly resistant P. aeruginosa strain was tested for its pathogenicity on day old specific pathogen free (SPF) chicks. Also, in vitro experiment was adopted to evaluate the efficacy of silver nanoparticles (Ag-NPs) against highly antibiotic-resistant P. aeruginosa strains. The overall isolation percentage was from all examined samples were 36.2% (571/1,576) representing 45.2% (532/1,176) from different birds' tissues and 39/400 (9.7%) from total egg samples. Some of isolated strains showed multidrug resistance (MDR) against kanamycin, amoxicillin, amoxicillin-clavulanic acid, neomycin, chloramphenicol, vancomycin, cefotaxime clavulanic acid, lincomycin-spectinomycin, co-trimoxazole, cefoxitin, gentamycin, and doxycycline. These MDR strains were also molecularly positive for ESBL and carbapenemase-encoding genes. MDR strain showed high pathogenicity with histopathological alterations in different organs in challenged birds. Main histopathological lesions were necrosis of hepatocytes, renal tubular epithelium, and heart muscle bundles. The MDR strain showed in vitro sensitivity to Ag-NPs. In conclusion, MDR P. aeruginosa is a serious pathogen causing high morbidity, mortality, and pathological tissue alterations. Ag NPs revealed a promising in vitro antimicrobial sensitivity against MDR P. aeruginosa and further in vivo studies were recommended.

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