Private Fish Farm Research Articles

Evaluation of Praziquantel effectiveness in treating Nile tilapia clinostomid infections and its relationships to fish health and water quality

This study aimed to conduct a multidisciplinary investigation integrating detailed morphology, molecular characterization, water parameters, histopathology alteration, and the trials of treatment of Clinostomum spp. In this study, 300 Nile tilapia (Oreochromis niloticus) were collected from the farmed and wild Nile River at Al Bahr Al Aazam, Giza Governorate to assess Clinostomid infection prevalence. Fish and water samples were collected from private fish farms, and water drains at Dakahlia, and Giza, Egypt. Analysis of the water revealed inadequate water quality, particularly in the fish farms. Snails and piscivorous birds were abundant at fish collection sites. The recovered Clinostomid MCs morphological characteristics and COI gene sequence analysis identified them as Clinostomum complanatum, C. phalacrocoracis, and Euclinostomum heterostomum. Clinostomid MCs disturbed the fish’s hematological and biochemical blood parameters. Bath treatment of parasitized fish with praziquantel (2 mg/L for 24 h) revealed a significant reduction in the number of vital MCs vs. infected fish (non-treated). Praziquantel (PZQ) is an effective and safe therapy for controlling Clinostomid infections affecting farmed Nile tilapia. The current findings indicate a link between poor environmental conditions and Clinostomum infections in tilapia. The study highlights the impacts of Clinostomid MCs on fish health and recommends bath treatment with PZQ as an efficient control method for these dangerous parasites to protect human and fish health.

Identification and florfenicol-treatment of pseudomonas putida infection in gilthead seabream (Sparus aurata) fed on tilapia-trash-feed

The present study aimed to determine the major cause of the high mortality affecting farmed gilthead seabream (Sparus aurata) and controlling this disease condition. Fifteen diseased S. aurata were sampled from a private fish farm located at Eldeba Triangle, Damietta, fish showed external skin hemorrhages, and ulceration. Bacterial isolates retrieved from the diseased fish were identified biochemically as Pseudomonas putida and then confirmed by phylogenetic analysis of the 16 S rRNA gene sequence. P. putida was also isolated from three batches of tilapia-trash feed given to S. aurata. Biofilm and hemolytic assay indicated that all P. putida isolates produced biofilm, but 61.11% can haemolyse red blood cells. Based on the antibiotic susceptibility test results, P. putida was sensitive to florfenicol with minimum inhibitory concentrations ranging between 0.25 and 1.0 µg mL− 1, but all isolates were resistant to ampicillin and sulfamethoxazole-trimethoprim. Pathogenicity test revealed that P. putida isolate (recovered from the tilapia-trash feed) was virulent for S. aurata with LD50 equal to 4.67 × 107 colony forming unit (CFU) fish− 1. After intraperitoneal (IP) challenge, fish treated with 10 mg kg− 1 of florfenicol showed 16.7% mortality, while no mortality was recorded for the fish group that received 20 mg kg− 1. The non-treated fish group showed 46.7% mortality after bacterial challenge. HPLC analysis of serum florfenicol levels reached 1.07 and 2.52 µg mL− 1 at the 5th -day post-drug administration in the fish groups received 10 and 20 mg kg− 1, respectively. In conclusion, P. putida was responsible for the high mortality affecting cultured S. aurata, in-feed administration of florfenicol (20 mg kg− 1) effectively protected the challenged fish.

Assessment of Heavy Metals Concentration in Different Organs of Labeo rohita and Cyprinus carpio

The current study was conducted to assess the concentration of heavy metals in rohu (Labeo rohita) and common carp (Cyprinus carpio). A total of three sites namely Rawal Lake Islamabad, Head Balloki, and a private fish farm in Muridke were selected. Fish were dissected and tissues from the liver, kidneys, gills, and muscles were separated. Chemical digestion of samples was carried out with aqua regia. Three metals namely chromium (Cr), cadmium (Cd), and mercury (Hg) were detected by using atomic absorption spectroscopy in the labs of Pakistan Council of Scientific and Industrial Research (PSCIR), Lahore, Pakistan. All metals were found at a higher level in different tissues of both the fish species. The overall trend of metals in the two fish species namely rohu and carp was recorded as Hg > Cd > Cr. It was observed that the level of Hg remained very high as compared to other metals. Statistical analysis was performed using one-way ANOVA and significant differences at p < 0.001 were noticed for the metals in different organs. While, independent sample t test showed non-significant differences at p > 0.483 between the two fish species. The liver was found to have the highest metal load, followed by the kidneys and gills. The metal load was above the permissible limit set by World Health Organization (WHO). However, the heavy metals concentration in muscles was below the permissible limit. It was noticed that heavy metal contamination was higher in Rawal Lake as compared to the private fish farm. It was concluded that contaminated water bodies are affecting the exposed organisms. So, there is a need to save them from pollutants for the best survival of aquatic life.

Heavy Metal Levels and Cancer Risk Assessments of the Commercial Denis, Sparus aurata Collected from Bardawil Lake and Private Fish Farm Waters as a Cultured Source, Egypt

Heavy metal pollution of natural and cultivated habitats may be caused by agricultural, industrial, and human activities. Fish living in these habitats easily accumulate metals in their organs; for food safety and human health, the heavy metals in fish flesh are of major concern due to the harmful nature of these pollutants even in low quantities. In this study, metals (Iron, Fe; Lead, Pb; Cadmium, Cd; Nickel, Ni; Copper, Cu and Zinc, Zn) in the muscle, liver, intestine, and gill of gilthead seabream (Sparus aurata, Denis is local name) were monitored to determine the contamination levels and to investigate the protective impact of cooking methods on the reduction or mitigation of metal levels. Although the Denis samples exhibited relatively low Pb and Cd levels, most fish samples had elevated levels of Fe and Zn. The examined metals accumulated at the highest level in the liver and gills compared to the other organs. Results showed that cooking methods had a considerable effect on concentrations of metals. However, the levels of metal in S. aurata from various sources were reduced significantly (P < 0.05) by frying, microwave, and grilling cooking, which was ordered in the following sequence as microwave cooking < grilling < frying. The consumption of Denis fish from different sources (wild and cultured) has no negative effects on health, according to a study of health hazards based on indices of carcinogenic and non-carcinogenic. The metal results indicated that different fish sources (wild and cultured) could be acceptable for human consumption. Data hypothesized a positive impact of awareness among the native community.

Studies on Vibrio campbellii as a newly emerging pathogen affecting cultured seabream (Sparus aurata) in Egypt

Aquaculture has become a crucial solution for addressing food scarcity worldwide, including Egypt. However, the intensification of aquaculture practices has led to water quality degradation and the emergence of new fish diseases, such as vibriosis. This study aimed to investigate the molecular typing, prevalence, pathogenicity, and environmental risk factors associated with Vibrio campbellii (V. campbellii) in cultured seabream. A total of 160 gilthead seabream, Sparus aurata (40 fish/season), along with 48 water samples (n = 12/season) were collected randomly and seasonally from private fish farms in the Suez Canal area over the course of a year for laboratory examinations. Clinical and postmortem inspections revealed characteristic signs and lesions similar to those observed in well-known vibrios infections. Bacteriological tests revealed the presence of V. campbellii strains in various internal organs. The isolated bacteria were identified morphologically, biochemically, and molecularly by targeting the 16S rRNA conserved gene. Histopathological examination was performed, providing insights into pathogen-induced tissue damage and septicemic disease progression. The prevalence of V. campbellii showed variable patterns across seasons, with higher proportions of cases in the summer. To examine the diagnostic performance of several water quality measures, the Receiver Operating Characteristic (ROC) curve analysis was performed. The results showed various levels of predictive performance for the outcome variable V. campbellii, with ammonia serving as a significant predictor for the variable of interest. The challenge results indicated a 100% survival rate in the controls, whereas the challenged group exhibited a mortality number of 6.00 ± 0.58, resulting in a survival rate of 70.00 ± 2.89%. The current study emphasizes how crucial it is to take into account seasonal parameters to comprehend the prevalence and seriousness of vibriosis in mariculture. The findings add to a better understanding of the impact of water quality on fish disease emergence and can benefit the creation of appropriate management measures to ensure aquaculture populations’ health and well-being.

Development of silver nano-based indirect ELISA and Dot-ELISA methods for serological diagnosis of a bacterial fish pathogen Aeromonas veronii

Rapid and accurate detection of bacterial pathogens is critical in controlling disease outbreaks affecting farmed fish. The present study aimed to develop a novel serological diagnostic approach using nano‑silver based Enzyme-linked immunosorbent assay (ELISA) for speedy detection of Aeromonas veronii infections in Nile tilapia. A. veronii isolates used in ELISA assays were recovered from moribund Nile tilapia during a disease outbreak in a private fish farm in Egypt. A. veronii isolates were identified based on alignment analysis of the gyrB and 16S rRNA gene sequences. A. veronii antisera used in ELISA assays were prepared in tilapia, and the bacterial antigens were formalin-killed. The cut-off values were 0.46 and 0.48 in traditional and nano-based ELISA. There were no cross-reactions with bacterial isolates (Aeromonas hydrophila, Aeromonas caviae, Aeromonas sobria, Pseudomonas fluorescens, and Vibrio vulnificus). The lowest antigen concentration that produced positive results after checkerboard titration in indirect-ELISA (i-ELISA) and dot ELISA was 15 μg and 250 ng of prepared antigen, respectively. Nano-ELISA and nano-based dot-ELISA antigen concentration was 10 μg and 100 ng, respectively. Sera concentration was 1:100 in indirect-ELISA and dot-ELISA, while it was 1:50 in nano-based ELISA and nano dot-ELISA. The i-ELISA successfully detected anti-Aeromonas IgG antibodies with 83.33% sensitivity and 66.67% specificity, while in the dot-ELISA, the sensitivity and specificity were 83.33% and 100%, respectively. Nano dot-ELISA had 100% sensitivity, specificity, and accuracy. Nano dot-ELISA assays have higher specificity, sensitivity, and accuracy than traditional ELISAs in detecting A. veronii. Further studies are needed to develop a rapid test kit for on-site field diagnosis.

Haematological alterations of mullet Planiliza abu (Heckel, 1843) naturally infected by Ergasilus mosulensis Rahemo, 1982 (Copepoda: Ergaslidae) in a private fish farm from Basrah Province, Iraq

Generally, there is no previous information about haematological parameters of parasitized fish maintained in fish farms in Al- Mashab area, Basrah, Iraq. In this study, the effects of parasitism by the copepod Ergasilus mosulensis. on haemoglobin (Hb), haematocrit (HCT), red blood cells (RBCS), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), and leucocytes were analysed in infected Planiliza abu. The high level of parasitism found in infected fishes was responsible for alterations in blood picture Hb, HCT, RBCS, MCV, MCH, MCHC, and leucocytes (P &gt; 0.05). This is the first report regarding hematology of cultivated freshwater fish which are infected with parasitic copepods in Basrah Province.

Diseases problems in cluttered sea bass Dicentrarchus Labrax reared in cages from Fingerlings until marketing size in Mariout Valley at King Mariout in Alexandria province

This study aimed to determine and identify the common bacterial infection in different stages of cultured sea bass during the different season. In addition Eexperimentally infected the sea bass with the Vibrio alginolyticus and Vibrio parahemolyticus. The aquarium trial was carried out with European seabass (Dicentrarchus labrax) in private fish farm at Borg El-Arab, Alexandria governorate Egypt. At total 50 of seabass was used during the study. The study lasted 10 weeks, starting with 50 ± 5 gram /fish. Prior to the start of the trial, the fish were fed with a commercial diet (45 percent CP, crude protein). Water quality parameters were monitored during fish acclimatization and throughout the trial. Water temperature, pH and dissolved oxygen remained within acceptable ranges for marine production during the trial. Our study concluded that, Vibrio alginolyticus and Vibrio parahemolyticus causes a great losses in cluttered sea bass Dicentrarchus Labrax reared in cages The presence of histopathological lesions in the internal organs clearly explained the septicemic nature of Vibrio infection. Altogether, the full confirmation of Vibrio infection ought to incorporate, examination of fishes for the visible clinical signs, postmortem examination, isolation of the causative agent using specific media and biochemical tests, and histopathological examination of the internal organs as a proof of septicemic nature of the Vibrio infection. The sensitivity test revealed sensitive to ciprofloxacin (Cipro 5μg), novobiocine (NV 30 μg), intermediate sensitivity was found to Oxytetracycline (OT 30 μg) while, the resistance was observed to amoxicillin (Aml 10 μg) and colisitine sulphate (CT 10 μg)

Streptococcosis in Sea Bream Sparus auratus with Special Reference to its Control by A Medicinal Plant

Isolation and identification of S. agalactiae from cultured sea bream by different microbiological methods, mortality rate, clinical signs, and postmortem lesions in sea bream in naturally and experimentally inoculated with a field sample of S. agalactiae. The aquarium trial was carried out with sea bream (Sparus auratus) in private fish farm at Borg El-Arab, Alexandria governorate Egypt. At total 50 of sea bream (Sparus auratus) was used during the study. The study lasted 10 weeks, starting with 50 ± 5 gram /fish. Prior to the start of the trial, the fish were fed with a commercial diet (45 percent CP, crude protein). Water quality parameters were monitored during fish acclimatization and throughout the trial. Water temperature, pH and dissolved oxygen remained within acceptable ranges for marine production during the trial. Our results concluded that, Streptococcus spp. (specifically S. agalactiae) is very pathogenic as they can affect sea bream which become a perfect host for Streptococcus infection. In addition, water quality parameter plays an important role in sea bream farming. In more specific, an optimum water quality parameter should be maintained to prevent “stress’’ in fish that can lead to outbreaks of disease. It can be concluded that the medicinal plant can help in prevention and control of bacterial infection in cultured fish, and because of their high resistance, to most antibiotics utilization in the prophylaxis or treatment of S. agalactiae infection should be avoided. The farmers must be used such approach to applied in the protocol of prevention of such infection in stead of chemotherapy.

The administrative efficiency of the private fish farms in fresh water in the Arab Republic of Egypt

The administrative efficiency of the private fish farms in fresh water in the Arab Republic of Egypt

Investigating the etiologies behind emergent mass mortalities of farmed Liza carinata juveniles from coastal farms at Damietta, Egypt

This study aimed to identify the mortality present in private fish farm Amyloodinium ocellatum and Cryptocaryon irritans were isolated from this outbreak affecting Liza carinata fingerlings at an earthen-based aquaculture facility in Damietta, Egypt. A total of 140 moribunds, L. carinata, were collected from the fish ponds during the mortality events. Physico-chemical analysis of water was analyzed. The skin, fins, gills, and eyes of each fish specimen were scraped gently onto slides in areas over 2 cm area. All smears were examined separately under the light microscope. Molecular identification of the parasites using analysis of ITS rDNA regions flanking both 18S and 28S rDNA genes of Amyloodinium protozoa and C. irritans. Identities of the detected parasites were confirmed by gene sequence and phylogenetic analysis. The majority of the examined fish (90%) were infected, 66.42% had a mixed infection, and 23.57% had a single infection either with A. ocellatum (10.71%) or C. irritans (12.85%).The mean intensity of A. ocellatum was 16.5 ± 2.03 in the skin and 13.18 ± 1.90 in the gills of infected fish, while that of C. irritans was 4.75 ± 1.05 in gills and 7.43 ± 1.45 in the skin, respectively. To control the emergent mortalities, affected ponds were treated using copper sulfate pentahydrate, hydrogen peroxides solutions, and amprolium hydrochloride powder in feed. Fish across the treated ponds were gradually improved with low morbidity and mortalityrates during the treatment period. The clinical disease was almost diminished at the end of the second week of treatment. Coinciding with the clinical improvement of the treated juveniles, microscopical examination of skin/gill scraps exhibited a marked decline in the number of protozoan parasites at the end of the second week of treatment.

Fish Parasites and Heavy Metals Relationship in Wild and Cultivated Fish as Potential Health Risk Assessment in Egypt

Despite wide studies of biomonitoring aquatic environment through dynamics of host–parasite interaction, bio-indicators to track the influence and accumulation of heavy metals on fish are still few. The present study sheds light on the relation between fish parasites and heavy metals as it threatens fish’s health and, as a consequence, that of humans after fish consumption. Samples of Nile tilapia (Oreochromis niloticus) were collected in Burullus Lake, a wild fish source, and from a private fish farm in Kafr El-Sheikh Governorate, in Egypt. They were exposed to various pollutants associated with anthropogenic activities to determine the levels of accumulation of Fe, Zn, and Cu, along with the top three most toxic metals (As, Cd, and Pb) in water and fish tissues of gills, intestine, liver, and muscles in both wild and farmedO. niloticus. The results showed the order of abundance: Fe &amp;lt; Zn &amp;lt; Pb &amp;lt; Cu &amp;lt; As &amp;lt; Cd. In waters of both farmed and wild fish, there was a significant negative relation between parasite prevalence and heavy metals, including Zn, Pb, and As. Also, there was a significant positive relation between parasite prevalence with Cu while no significant relation was found with Fe and Cd. Heavy metal content was significantly higher (p&amp;gt; 0.05) in non-infected than infected farmed and wildO. niloticus. In addition, a significantly decreased concentration (p&amp;gt; 0.05) of essential heavy metal was recorded in wild fish compared to farmed specimens, while non-essential heavy metal was significantly higher (p&amp;gt; 0.05) in wild compared to farmed fish. Bioaccumulation factors (BAF) of different organs ofO. niloticuswere ranked in ascending order: Liver &amp;gt; Gills &amp;gt; Intestine &amp;gt; Muscles. In general, the risk assessment showed safe human consumption of farmed and wild fish under the reported environmental conditions in this study. Moreover, the parasite's presence can be adopted as a surrogate indicator to estimate the potential impact of heavy metal pollution and accumulation.

Isolation and Identification of Bacteria found in the milt of cultured Clarias gariepinus

Bacteria identification in fish is important; hence it provides update information on emerging and existing organisms thereby enriching the gene bank on fish disease. This study investigated bacteria associated with milt in cultured samples of African catfish- Clarias gariepinus. Catfish broodstock were collected from private Fish Farm in Ogun State, Nigeria. Fish samples were taken to the Microbiology laboratory, Federal University of Agriculture, Abeokuta Ogun State for milt microbial analyses, and amplicon were taken to International Institute of Tropical Agriculture, Ibadan for molecular characterization. Bio-edit was use for importing and mining nucleotide sequences into gene bank. The results revealed that the following bacterial organisms were present in the milt of Clarias gariepinus: Aeromonas caviae, Proteus mirabilis, Serratia rubidaea, Pseudomonas mosselii, Acinetobacter soli and Klebsiella variicola. The Basic Local Alignment Search Tools revealed the percentage similarity ranging from 86- 97.04% and their accession numbers. These bacteria indicated high levels of faecal contamination in the environment. In conclusion, bacteria were found in the milt of cultured catfish and are capable of being pathogenic to humans and may increase the vertical transfer to fry during breeding and rearing stage.

Newly Emerging MDR B. cereus in Mugil seheli as the First Report Commonly Harbor nhe, hbl, cytK, and pc-plc Virulence Genes and bla1, bla2, tetA, and ermA Resistance Genes.

BackgroundBacillus cereus is a common food poisoning pathogen in humans. This study aimed to investigate the prevalence, molecular typing, antibiogram profile, pathogenicity, dissemination of virulence and antibiotic resistance genes associated with natural B. cereus infection among Mugil seheli.MethodsConsequently, 120 M. seheli (40 healthy and 80 diseased) were obtained from private fish farms in Port-said Governorate, Egypt. Afterward, samples were processed for clinical, post-mortem, and bacteriological examinations. The recovered isolates were tested for antimicrobial susceptibility, phenotypic assessment of virulence factors, pathogeneicity, and PCR-based detection of virulence and antibiotic resistance genes.ResultsB. cereus was isolated from 30 (25%) examined fish; the highest prevalence was noticed in the liver (50%). The phylogenetic and sequence analyses of the gyrB gene revealed that the tested B. cereus isolate displayed a high genetic similarity with other B. cereus strains from different origins. All the recovered B. cereus isolates (n =60, 100%) exhibited β-hemolytic and lecithinase activities, while 90% (54/60) of the tested isolates were biofilm producers. Using PCR, the tested B. cereus isolates harbor nhe, hbl, cytK, pc-plc, and ces virulence genes with prevalence rates of 91.6%, 86.6%, 83.4%, 50%, and 33.4%, respectively. Moreover, 40% (24/60) of the tested B. cereus isolates were multidrug-resistant (MDR) to six antimicrobial classes and carried the bla1, bla2, tetA, and ermA genes. The experimentally infected fish with B. cereus showed variable mortality in direct proportion to the inoculated doses.ConclusionAs far as we know, this is the first report that emphasized the existence of MDR B. cereus in M. seheli that reflects a threat to the public health and the aquaculture sector. Newly emerging MDR B. cereus in M. seheli commonly carried virulence genes nhe, hbl, cytK, and pc-plc, as well as resistance genes bla1, bla2, tetA, and ermA.

Detection, diagnosis, Koch’s postulate, hepatorenal and antioxidant indicators for some systemic pathogenic fungi invading the liver and kidneys of African catfish ( Clarias gariepinus ) in Egypt with a histopathological approach

Recently, systemic fungal infections have emerged as significant causes of fish morbidity and mortality. Hence, the current study investigates the occurrence of some pathogenic systemic fungi inducing severe lesions in the liver and kidneys of African catfish. Two hundred diseased African catfish were collected from private fish farms in Egypt, and only 120 fish were infected with 212 different fungal isolates at a rate of 60%. The seasonal survey revealed isolation of 72 isolates of yeast (Candida albicans) and 140 isolates of moulds including non-pigmented moulds, Aspergillus ochraceous and Aspergillus flavus, as well as pigmented mould (Cladosporium herbarum). The isolated fungi induced characteristic post-mortem lesions. To date, this is the first report for isolation of C. herbarum and C. parapsilosis from Nile catfish liver and kidneys. Various techniques were performed to identify the fungi including gross observation, microscopic examination of tissue squashes, in vitro culture and histopathology. Koch's postulate was fulfilled to confirm the fungal pathogenicity. The challenged fungi altered the hepatorenal indicators (ALP, AST, ALT, urea and creatinine) and oxidative stress biomarkers (MDA, CAT and SOD). The results indicate the virulence of the isolated fungi, and future studies are needed for treatment trials.

Effect of Replacing Fish Meal in Fish Diet with Shrimp by-Product Meal on Growth Performance, Feed Utilization, Length-Weight Relationship and Condition Factors of Nile Tilapia, Oreochromis niloticus (Linnaeus, 1758)

The present work aimed to study the effect of replacing fish meal (FM) in the fish diet with shrimp by-product meal (SBM) on the growth performance parameters of the Nile Tilapia, Oreochromis niloticus. A total of 200 specimens of monosex O. niloticus fries were obtained from a private fish farm at Kafr El-Sheikh Governorate. They were transported to the fish laboratory at the Animal House of Zoology Department, Faculty of Science, Al-Azhar University. After two weeks for acclimation, the fish were divided into 5 groups, 2 replicates for each group (20 fish in each replicate). The five experimental diets were: C: control group with20 % fish meal (FM) and 0 % shrimp by-product meal (SM); T1, T2, T3, and T4 FM was replaced with SBM as 25 %, 50 %, 75 % and 100 %, respectively. Results indicated that the highest final length, growth in length, length gain, daily length gain and other growth performance parameters including the relationship between length and weight and condition factors of O. niloticus were recorded in T4 group (fed diet in which fish meal was completely replaced with shrimp by-product meal); while, their lowest values were recorded in control group. On the other hand, feed utilization parameters (feed intake, food conversion ratio, the maximum values of feed efficiency ratio and protein efficiency ratio) were recorded in T4 group and the minimum values were recorded in T3 group (fed diet in which 75 % of fish meal was replaced with shrimp by-product meal).

Incidence of parasitic infection in adult and juvenile Clarias gariepinus in a private fish farm, Yola, Adamawa state

The study was conducted in Gesedaddo’s farm, Yola, Adamawa state, Nigeria to determine the prevalence of parasites infecting Clarias gariepinus between June to November, 2016. A total of one hundred and thirty-two (132) fish were sampled for parasitic investigation. Out of these, cultured adults (66) and cultured juveniles (66) respectively were procured from the farm and examined for parasites using the keys of fresh water fish parasite pictorial guide and were examined for parasitic infections using direct wet mount microscopy and stained smears. A total number of 43 adult Clarias gariepinus were infected out of which 132 parasites were identified, while in juvenile Clarias gariepinus, a total number of 10 fish were infected in which 30 parasites were identified in Gesedaddo’s farm. Seven (7) classes of parasites and eleven (11) parasite species, which are namely, Piscinoodinium, (Dinoflagellata), Coccidia, Spironucleus vortens, (Flagellata), Chilodonella, Tetrehymena, (Motile ciliate), Capillaria, Contracaecum, (Nematoda), Microsporidians, (Protozoa), Saprolegnia sp, (Oomycota), Digeneans, and Planarian (Trematoda) were recorded from the gills, stomach, intestine, and skin mucus of the cultured Clarias gariepinus on the farm. Parasitic infestation was higher in the intestine with 63 (47.73) and the least was identified 6 (4.55) on the skin for adult Clarias gariepinus while the highest number of parasites identified in juvenile Clarias gariepinus was found on the skin with total number of 11 (36.67). Among the class of parasites identified, it was recorded that the highest parasitic load occurred most in the class protozoan with 45 (34.09%) and 17 (56.67) in adult and Juvenile C. gariepinus respectively. The Chi square value shows that there was no significant difference (p>0.05) between the prevalence and intensity of parasitic infection in adults and juvenile C. gariepinus based on sex. Parasitic infestations in the adult and juvenile female were significantly higher than in the adult and juvenile male in cultured Clarias gariepinus. There was a significant difference between incidence of infestation, standard length and body weight of Clarias gariepinus while there was no significant difference (p> 0.05) between parasitic load.

Aeromonas veroniidetection in Egyptian fish farms with summer tilapia mortality outbreaks and the role of formic acid in limiting its spread

From 45 private fish farms, 641 tilapia samples were collected, which suffered from tilapia summer mortality outbreaks at different localities. The findings of the conventional test and 16S rRNA gene sequence recognition indicated that the isolated bacterium from the examined farms is Aeromonas veronii. A 15-day feeding trial was conducted to determine the effects of formic acid (FA) on biochemical parameters, immunological status, cortisol levels and total gut bacterial population of A. veronii-challenged tilapia. Fish were divided into five groups. The first and second groups served as control-negative and control-positive groups, which were intraperitoneally injected with 0.2-ml sterilized tryptic soy broth and A. veronii (4.3 × 106), respectively, and both were fed with a basal diet. Groups 3–5 were intraperitoneally injected with 0.2-ml A. veronii (4.3 × 106), fed a basal diet until clinical signs appeared and fed on a medicated diet containing florfenicol 15 mg/kg fish body weight and 0.5% and 1% FA respectively. The results suggest that including 1% FA in the diet lowered mortality and relieved the pathogenic effects of A. veronii on the general health status of tilapia fish.

Primary signs of internal organ diseases in carp in case of standard condition violations in fish farming ponds

Hematological and histopathological study results of adult carp from a private fish farm are presented. Abnormalities in the main hematological parameters (blood elements ratio, leukocyte formula, erythropoiesis level, possible pathologies of erythrocytes) were not revealed. One third of the examined fish were found to have abnormalities in the tissues of gills, liver, and heart muscle in the form of minor focal formations (detachment of the gill epithelium, dissection of myofibrils, disorders of glycogen metabolism, foci of necrosis and infiltration) which indicates the initial stage of the pathological process. Kidneys, gonads, and somatic muscle fibers showed no signs of pathology. The main factors determining the primary signs of internal organ diseases are water quality (water saturated with magnesium, calcium, and iron salts, increased hardness) and an unbalanced diet (primarily, an insufficient amount of raw protein) that does not meet the standards adopted in fish farming. The registered initial signs of the pathological process in the gills, liver and heart muscle can be leveled by improving the carp keeping conditions.

Assessment the using of silica nanoparticles (SiO2NPs) biosynthesized from rice husks by Trichoderma harzianum MF780864 as water lead adsorbent for immune status of Nile tilapia (Oreochromis niloticus)

Rice husks (RHs) was used as a substrate for biosynthesis of high-value Silica nanoparticles (SiO2NPs). An isolate of Trichoderma harzianum MF780864 (T. harzianum) was isolated and identified based on the Internal Transcribed Spacers (ITS) sequences; it showed the potentiality to induce SiO2NPs in the process of RHs biotransformation. SiO2NPs were produced extracellularly and their size was of about 89 nm. SiO2NPs characterized by oval, rod and cubical particles by using Transmission Electron Microscope (TEM).The Fourier transform infrared spectroscopy (FTIR) confirmed the presence of various functional groups of biomolecules and capping protein, encapsulating SiO2NPs. Water and fish samples were collected from private fish farms in El-Sharkia Governorate, Egypt. Lead (Pb) was detected from water and fish samples at its highest concentration at about 0.088 mg/L. The adsorption capacity of Pb by SiO2NPs was evaluated by testing different concentrations of SiO2NPs viz. 1, 2, and 3 mg/L, wherein 1 mg/L revealed the highest Pb adsorption efficiency. Within laboratory trials, the results indicated that highest Pb adsorption efficiency revealed through the increasing of SiO2NPs concentrations until 120 h. In vivo trial that lasted for 8 weeks, Nile tilapia (Oreochromis niloticus) (29.78 ± 0.36 g body weight) supplemented with 0.088 mg/L Pb was divided into four experimental groups having three replicates (15 fish/replicate; 45 fish/group). The results showed that SiO2NPs supplementation through water revealed significant increase in growth and hematological parameters of O. niloticus. Moreover, enhancement of antioxidant capacity (TAC), and immune related gene expression of IL-1β were increased in the presence of SiO2NPs compared with the groups of Pb exposure. Moreover, Pb residue level in fish muscles was noticeably decreased in the SiO2NPs treated groups. Thus, this research opens up other possibilities in the field of using SiO2NPs as a lead adsorbent for water bioremediation.