Mohamed Abdelsalam

This paper is a part of a multi-disciplinary research "Application of Decentralized On-Site Water Treatment System in Egypt for Use in Agriculture and Producing Safe Fish and Animal Proteins". The project aimed to investigate the environmental impact of implementing sewage water before and after treatment using the effluent of the on-site decentralized Japanese' Johkasou system, in agriculture and producing fish protein. The aim is to establish such system in Egypt to strengthen the sanitary conditions of water resources. In the present study, the impact of the sewage pollution in some fish farms at El-Fayyum, Port Said and El-Dakahlia governorates in Egypt was carried out. Water and fish (Oreochromis niloticus and Mugil cephalus) samples were collected from private fish farms of such localities. Bacteriological and chemical examination of water samples revealed the existence of coliforms and many other bacterial species of significant human health hazards. The chemical parameters of water showed a marked deviation from normal levels while examination of fish flesh specimens indicated contamination with Streptococcus Sp., Staphylococcus Sp., and Salmonella in all examined localities. Other bacterial isolates of human health importance (Morganella morganii, Pseudomonas cepacia and Enterococcos durans) were identified. The parasitological examination revealed the presence of encysted metacercariae (EMC); Diplostomatidae, Prohemistomatidae and Heterphyidae. Moreover, two protozoan parasites (Mxyoboulus tilapiae and Ichthyophthirius multifilis) were also recorded. The histopathological examination revealed mild tissue reaction in case of bacterial infection and severe pathological lesions in different organs in case of EMC infection. Lamellar hyperplasia and mononuclear cell infiltration in branchial tissue was common findings. In skeletal muscles, atrophy of muscle fibres, myolysis and myophagia were detected.

Hydraulic fracturing (fracking) chemicals are used to maximize the extraction of hard-to-reach underground energy resources. Large amounts of fracking fluid could escape to the surrounding environments, including underground and surface water resources, during the chemical mixing stage of the hydraulic fracturing water cycle due to equipment failure or human error. However, the impact of pollution resulting from operational discharges is difficult to assess in aquatic ecosystems. In this study, pathological investigations, chromosomal aberrations, DNA damage, and biochemical and hematological parameters were used to evaluate the effects of such chemicals on Nile tilapia. Chromosomal aberrations are considered very sensitive genetic markers of exposure to genotoxic chemicals and are used as indicators of DNA damage. The appearance of different types of chromosomal aberrations (gaps and breaks) due to chemical exposure was significantly reduced by treatment with spirulina. Various deleterious findings in Nile tilapia, in the current study, could attributed to the presence of fracking chemicals in the aquatic environment. However, the presence of spirulina in the diet reduced the hazards of such chemicals. In addition, cytogenetic studies in the current work revealed the importance of spirulina in ameliorating the genotoxic effects of a mixture of some chemicals used in fracking.

Upon the demand of a private fish farmer, this study was applied to assess the influence of electro-fishing adopted by some Egyptian fish farmers on the fish welfare and quality. Therefore, a total of 60 Nile tilapia (Oreochromis niloticus) were sampled; from which 30 were stunned by electrofishing and the remainders by conventional fishing. Biochemical analysis (oxidative stress and energy status), meat quality based on total bacterial count (TBC) and pathological alterations were assessed. Biochemical analysis in both liver and muscle tissue showed that electro-stunned fish exhibited low oxidative stress and high energy status. Meat of electro-stunned fish showed an acceptable limit of TBC (Max. limit 107) while the histopathological examination revealed various tissue reactions. These were in the form of congestion in branchial, hepatoportal, brain and splenic blood vessels with edema in brain and pericardium. In addition, there was mild inflammatory reaction together with the presence of eosinophilic granular cells and perivascular melanophores aggregation in both branchial and muscular tissue. As a consequence of this work, we recommend the use of electrofishing method in Egypt after modifying the current tool by reducing applied voltage. Further studies and more optimization are needed to cover both fish farmers and animal welfare issues, and take in consideration the human safety precautions.

UNLABELLED: The nucleotide sequence analysis of the gyrB gene indicated that the fish Aeromonas spp. isolates could be identified as Aeromonas hydrophila and Aeromonas veronii biovar sobria, whereas chicken Aeromonas spp. isolates identified as Aeromonas caviae. PCR data revealed the presence of Lip, Ser, Aer, ACT and CAI genes in fish Aer. hydrophila isolates, ACT, CAI and Aer genes in fish Aer. veronii bv sobria isolates and Ser and CAI genes in chicken Aer. caviae isolates. All chicken isolates showed variable resistance against all 12 tested antibiotic discs except for cefotaxime, nitrofurantoin, chloramphenicol and ciprofloxacin, only one isolate showed resistance to chloramphenicol and ciprofloxacin. Fish Aeromonads were sensitive to all tested antibiotic discs except amoxicillin, ampicillin-sulbactam and streptomycin.

SIGNIFICANCE AND IMPACT OF THE STUDY: Many integrated fish farms depend on the application of poultry droppings/litter which served as a direct feed for the fish and also acted as pond fertilizers. The application of untreated poultry manure exerts an additional pressure on the microbial world of the fish's environment. Aeromonas species are one of the common bacteria that infect both fish and chicken. The aim of this study was to compare the phenotypic traits and genetic relatedness of aeromonads isolated from two diverse hosts (terrestrial and aquatic), and to investigate if untreated manure possibly enhances Aeromonas dissemination among cohabitant fish with special reference to virulence genes and antibiotic resistant traits.

Native and imported Scomber Japonicus were collected from Egypt and found to be infected with the third stage larvae (L3) of Anisakidae. The Anisakidae larvae were found encapsulated tightly coiled in the mesenteries associated with pyloric ceca and the serosal surface of visceral organs and/or uncoiled larvae free in the abdominal cavity of infected S. japonicus. The prevalence, mean intensity, and mean abundance of L3 were 80%, 24.4, and 19.5 in imported fish, and they were 36%, 7.36, and 2.65 in native fish, respectively. These larvae were identified as Anisakis simplex type 1 based on their morphological and molecular characteristics. The larvae were cylindrical in shape, and the oral openings had a prominent boring tooth. The esophago-intestinal junction (ventriculus) was oblique. The bodies of the larvae were covered with a transversely striated cuticle. The posterior end of the larvae had a short mucron or spine. Subsequently, phylogenetic analysis of the internal transcribed spacer region and COI gene of investigated larvae confirmed the identification of A. simplex when compared with relevant species sequences in GenBank. Histopathological examination revealed multiple A. simplex larvae in the abdominal cavity near the pyloric appendages, stomach, and under the visceral peritoneum, which appeared as a very thin and glistening capsule covering the larvae with a prominent adhesive fibrinous peritonitis together with mononuclear and eosinophilic granular cell infiltration. The importance of A. simplex infection in both native and imported S japonicus in Egypt is emphasized.