Diseases In Fish Farming Research Articles

Assessment of Single-Dose Pharmacokinetics of Oxolinic Acid in Rainbow Trout and Determination of InVitro Antibacterial Activity Against Pathogenic Bacteria From Diseased Fish.

In response to the heightened risk of bacterial diseases in fish farms caused by increased demand for fish consumption and subsequent overcrowding, researchers are currently investigating the efficacy and residue management of oxolinic acid (OA) as a treatment for bacterial infections in fish. This research is crucial for gaining a comprehensive understanding of the pharmacokinetics of OA. The present study investigates pharmacokinetics of OA in juvenile rainbow trout. The fish were given a 12 mg kg-1 dose of OA through their feed, and tissue samples were collected of the liver, kidney, gill, intestine, muscle, and plasma for analysis using LC-MS/MS. The highest concentrations of the drug were found in the gill (4096.55 μg kg-1) and intestine (11592.98 μg kg-1), with significant absorption also seen in the liver (0.36 L/h) and gill (0.07 L/h) (p < 0.05). The liver (0.21 L/h) and kidney (0.03 L/h) were found to be the most efficient (p < 0.05) at eliminating the drug. The study also confirmed the drug antimicrobial effectiveness against several bacterial pathogens, including Shewanella xiamenensis (0.25 μg mL-1), Lactococcus garvieae (1 μg mL-1), and Chryseobacterium aquaticum (4 μg mL-1). The study concludes significant variations among different fish tissues, with higher concentrations and longer half-lives observed in the kidney and intestine. The lowest MIC value recorded against major bacterial pathogens demonstrated its therapeutic potential in aquaculture. It also emphasizes the importance of understanding OA pharmacokinetics to optimize antimicrobial therapy in aquaculture.

The effect of Astragalus polysaccharides on the repair of adverse effects in largemouth bass (Micropterus salmoides) under enrofloxacin stress

Antibiotics have important role in controlling the outbreak of bacterial diseases in fish farming, but long-term use or persistent existence of antibiotics in water can cause adverse effects on aquatic animals. In order to evaluate repairing effect of Astragalus polysaccharides (APS) on damaged intestine of fish under enrofloxacin (ENR) stress, ENR-pretreated (1.0 mg/L, 7 days) largemouth bass were randomly divided into two groups, and subsequently were fed basal diet and diet supplemented with 1.0 g/kg APS for 14 days. Intestine tissue and content were sampled on day 0 (D0), days 7 (D7), days 21 (D21_APS and D21) to detect the intestinal structure, intestinal microbiota structure, oxidative stress, non-specific immune and inflammatory response.Intestinal tissue section showed that the height, width of intestinal villi, and muscular thickness in D21_APS were significantly greater than those on D0, D7, and D21 (P < 0.05). APS-supplemented diet was significantly increased expression of tight junction protein related genes occludin, claudin-1, ZO-1 (P < 0.05). APS addition significantly improved the activities of catalase (CAT) and peroxidase (POD) and decreased superoxide dismutase (SOD) activity (P < 0.05). The activity of CAT and SOD in D21_APS and D0 were similar. The highest activities of acid phosphatase (ACP), lysozyme (LZM) and alkaline phosphatase (AKP) were found in D21_APS group. The expression of proinflammatory factors IL-1β and TNF-α in D21_APS and D21 were significantly down-regulated compared to that of D7, while anti-inflammatory factor IL-10 was up-regulated (P < 0.05). Compared with D7 group, quinolone resistance gene (qnrB) in D21 and D21_APS groups were significantly down-regulated, and in contrast to D21 group, qnrB and qnrS genes in D21_APS group were significantly down-regulated (P < 0.05).High-throughput 16SrRNA gene sequencing revealed proportion of Cyanobacteria in intestinal microbiota increased from 8.23% to 52.66%, while Firmicutes decreased from 28.54% to 2.03% after ENR treatment. In D21 group, Proteobacteria was notable decrease compared to D0, while Firmicutes increased. In D21_APS, the dominant bacteria were Proteobacteria, Fusobacteriota and Firmicutes, and Acinetobacter, Cetobacterium and Aeromonas were the predominant genera. Cluster analysis indicated that bacterial community structure in D21_APS has a similar level to D0 at phylum level. Feeding APS increased abundance of genes related to styrene, isoleucine and lysine degradation; propanoate, butanoate phenylalanine, and tryptophan metabolism; lipopolysaccharide biosynthesis; bacterial secretion system; cell motility and secretion at KEGG pathway Level 3 compared to the basal diet. Taken together, APS can repair the damage of intestinal structure and intestinal microbiota caused by ENR.

Effect of Methyl Violet to Mulberry Silkworm Some Breeds Eggs

To liquidate the larvae, the methyl violet (C24H28N3Cl), used against fungal diseases in fish farming, was used. The goal is to establish physiological responses in different phases of development after treating local and introduced mulberry silkworm breeds of with aqueous solutions of methyl violet. Exogenous exposure to eggs led to the formation of a negative reaction. It has been established that treatment of silkworm eggs with water and a 0.001% solution of methyl violet (from October 20 to November 15, 2018) reduces the weight of the silk layer of cocoons with statistical accuracy by 33.0% (−78.5 mg) and 22.5% (−49 .0 mg) respectively (p&lt;0.001). A negative effect also occurs in other physiological indicators: there is a difference in the weight of caterpillars, cocoons and pupae, and a slight deviation occurs in the weight of caterpillars before cocooning in the aquatic version. The results of this research can be used in developing issues such as identifying more stable and promising mulberry silkworm breeds in the conditions of Azerbaijan, as a prerequisite for predicting the successful introduction of mulberry silkworm.

Molecular characterization and antibiotics resistance of Aeromonas species isolated from farmed African catfish Clarias gariepinus Burchell, 1822

BackgroundAeromonas species are one of the most important etiologies of diseases in fish farms, leading to clinical manifestation and mortality and are associated with public health risks. This study aimed to investigate the prevalence, phenotypic and molecular characteristics of Aeromonas species isolated from farmed Clarias gariepinus using 16 S rRNA sequencing. Additionally, their antibiogram and multiple antibiotic resistance index were determined using a disc diffusion test.ResultsA total of 230 Aeromonas strains were isolated from Clarias gariepinus with 40.9% obtained from diseased fish, and 25% isolated from apparently healthy ones. Five different species including Aeromonas caviae, Aeromonas veronii, Aeromonas hydrophila, Aeromonas dhakensis and Aeromonas enteropelogenes were fully identified and genetically characterized. Based on the available literature, this is the first report of Aeromonas enteropelogenes from the study area. The phylogenetic analysis showed genetic heterogeneity and distance within the species and the reference strains. The multiple resistant Aeromonas species were susceptible to ciprofloxacin, gentamycin, and florfenicol. The Aeromonas species’ multiple antibiotic resistance index values varied between 0.20 and 0.80 and were isolated from the farms where antibiotics were intensively used.ConclusionsThe diversity of multidrug-resistant Aeromonas species isolated from fish farms is a major threat to fish production giving us more understanding of epidemiology and the multidrug Aeromonas species with a MAR index of greater than 0.2 were isolated from farms where antibiotic use was widespread. As a result, a considerably increased danger of multiple antibiotic resistance spreading to the fish culture environment may impact aquaculture production. Hence there is a need for appropriate and monitored drug usage.

Biosecurity in Fish Farming: Implementation of the HACCP System at the Djissoumakö Fish Farming Centre - Urban Commune of Siguiri, Guinea

This study was carried out from 10 January to 20 February 2022 in the urban and peri-urban area of Siguiri and aimed to learn about the application of biosecurity measures in some fish farms in Siguiri. To this end, 6 fish farms were surveyed on the basis of a targeted sampling based on the criteria of accessibility, cooperation of fish farmers and the functional state of these farms, and 20 biosecurity variables were taken in to account.&#x0D; Of all the fish farms surveyed, only one (1) farm applied biosecurity measures, i.e. 15%, and the other five (5) saidtheyhad no knowledge of biosecurity, i.e. 85%. &#x0D; In conclusion, the knowledge and application of biosecurity measures could undoubtedly help prevent diseases in fish farms, event houghthey are rare, and improve the productivity of fish farmers.

Effect of probiotics Zoonorm and Subalin on the immunophysiological system and microbiocenosis of carp

Aquaculture is a fast-growing sector in Russia. To grow fish to a greater extent than for other agricultural objects, it is necessary to preserve and maintain natural habitat conditions. Minor changes in the aquatic environment, such as changes in pH, temperature fluctuations, and the presence of organic pollutants can lead to a decrease in the number of fish. Use of antibiotic drugs for the prevention and treatment of diseases in fish farming can lead to a change in the microbiocenosis of fish and the hydroecosystem, the appearance of antibiotic-resistant strains of pathogenic microorganisms and a change in the immunophysiological status of the fish organism. To date, a promising and effective therapeutic and prophylactic agent in fish farming is the use of probiotics, which have pronounced antimicrobial activity against pathogenic and conditionally pathogenic microorganisms, immunocorrecting and anti-inflammatory effect. As a result of our research, we have established the effectiveness of the use of preparations Subalin containing Bacillus subtilis and Zoonorm containing live bacteria Bifidobacterium bifidum in the cultivation of carp. A positive effect on the increase in body weight of fish was revealed, the level of contamination of parenchymal organs of fish with bacterial flora decreased, specific and nonspecific resistance increased.

Phytobiotics blend as a dietary supplement for Nile tilapia health improvement

Functional additives of natural origin included as dietary supplements have become an alternative to synthetic antibiotics to improve health and resistance to ecologically correct pathogenic diseases in fish farming. We tested whether incorporating a mixture of phytobiotics such as volatile oils of thyme, red thyme and pepper rosemary into the diet improves growth performance, oxidative stress, immune and hematological responses and resistance of juvenile Nile tilapia when subjected to a challenge with Aeromonas hydrophila compared to a synthetic antibiotic (enrofloxacin). The experimental design was completely randomized with three experimental groups: control diet, diets containing a mixture of thyme phytobiotic essential oils, red thyme and pepper rosemary (FTB) and the synthetic antibiotic enrofloxacin (ATB), with four replicates (14 fish per repetition/experimental unit). Plasma glucose levels, leukocyte respiratory activity, serum lysozyme levels, number of circulating erythrocytes and leukocytes, levels of lipid peroxidation (LPO), catalase (CAT) and glutathione S-transferase (GST) activity at the end of 20 days of feeding (phase) were evaluated and 24 h after exposure to bacteria (phase II). The supplementation of FTB and ATB did not change the performance parameters, but it was sufficient to increase lysozyme, leukocytes, neutrophils and monocytes after the bacterial challenge, reduction of CAT and LPO activity and the highest GST activity (P < 0.05). The results of the present study suggest that FTB as a dietary supplement has benefits and can replace synthetic ATB, including supplementation with FTB for 20 days to provide greater antioxidant protection in Nile tilapia, mitigate the impacts of stressors and modulate immunity, providing to fish greater resistance and protection against diseases.

Ecological risk assessment of Piper aduncum essential oil in non-target organisms

ABSTRACT One possible alternative to chemotherapeutic agents in the treatment and prevention of diseases in fish farms is the use of Piper aduncum essential oil. However, ecotoxicological data are required to ensure its proper use and to prevent adverse effects on non-target organisms. These data are relevant since this essential oil is described as having insecticidal, molluscicidal and cytotoxic activitiy that may be associated with its chemical composition. Thus, the aim of this study was to evaluate the ecotoxicity of P. aduncum essential oil to five test organisms using the species sensitivity distribution (SSD) statistical approach. The chemical composition of the essential oil was characterized by means of gas chromatography coupled to mass spectrometry (GC-MS) and gas chromatography-flame ionization detection (GC-FID) for identification and quantitation purposes, respectively. The main component (75.5%) of the essential oil was dillapiole. The hazardous concentration for 5% of biological species (HC5) was calculated to determine the 95% protection level, resulting in a value of 0.47 mg L-1 (with a confidence interval of 0.028 - 1.19 mg L-1. ). A concentration range related to the level of protection for aquatic communities (the predicted no-effect concentration, PNEC) was determined through the application of safety factors to the HC5 value. The ecotoxicity parameters showed that P. aduncum essential oil can be used safely in water bodies at a concentration equal to or below 0.09 mg L-1.

Efficacy of some synthetic antibiotics on Streptococcus pneumoniae and Proteus mirabilis isolated from fish tanks

Effects of some synthetic antibiotics on Streptococcus pnemoniae and Proteus mirabilis isolated from cultured Clarias gariepinus, an important food fish raised in a concrete tank was carried out to ascertain their remedies on mortalities of the Clarias gariepinus adult fish. Streptococcus pnemoniae and Proteus mirabilis were isolated from the gill and skin of diseased fish and water samples and identified by standard microbiological methods.The bacteria isolates were tested for sensitivity on ten (10) antibiotics namely Amoxycillin, Gentamicin, Nitrofurantoin, Erythromycine, Augmentin, Tetracycline, Naladoxic acid, Cotrimoxazole, Cloxacillin and Ofloxacin. These organisms reacted differently to the different antibiotics that were used - Ofloxacine, Gentamycin and Erythromycine had highest zones of inhibition of 26mm and 26mm, 24mm and 19mm, 16mm and 17mm respectively around Streptococcus pnemoniae and Proteus mirabilis, but Naladoxic acid, Augmentin, Cloxacillin and Amoxycillin had no inhibition zones around both organisms. It is therefore recommended that Ofloxacine, Gentamycin and Erythromycine can be used to combat S. pnemoniae and P. mirabilis diseases in fish farms because of their high antibacterial potentials against the test organisms.

Spring dynamics of cyprinids parasitofauna under pond aquaculture conditions in the Astrakhan region

The results of spring monitoring of invasive diseases of Cyprinids in fish farms of the Astrakhan region are presented. Indicator representatives of the main species groups of the ectoparasite fauna of Cyprinids (monogenetic trematodes, fish leeches, crustaceans and unicellular skin parasites) are considered, and the quantitative dynamics of invasions in spring season under aquaculture conditions in the Astrakhan region are considered. In the period from April to May 2020, 170 samples of carp fish of five species were examined: carp, bream, roach, silver bream, rudd. The study was carried out by the parasitological method on live fish, the intensity of invasion was determined. The causative agents of the following invasive diseases of cyprinids were identified: dactylogyrosis, argulez, trichodinosis, diplozoonosis, piscicolez. For all detected parasites, a low intensity of invasion was noted (1–20 ind. per fish), which corresponds to the baseline values for pond rearing of Cyprinids and allows us to speak about satisfactory conditions for fish. The number of leeches averaged 10 specimens per fish, which is rather high in spring and indicates inadequate preparation of ponds for the fish-breeding season, or early arrival of spring; however, according to quantitative criteria, this corresponds to a low intensity of invasion. In general, the results obtained are consistent with the background presence of ectoparasites on cyprinids during pond rearing and allow us to speak about satisfactory conditions for keeping fish in the commercial farms of the Astrakhan region. The effect of earlier periods of the onset of high water temperatures in the river and ponds in recent years (2019–2020) on the development of the dynamics of invasive diseases in fish farms of the Astrakhan region requires additional study

Comparative transcriptomics reveal conserved impacts of rearing density on immune response of two important aquaculture species

Infectious diseases represent an important barrier to sustainable aquaculture development. Rearing density can substantially impact fish productivity, health and welfare in aquaculture, including growth rates, behaviour and, crucially, immune activity. Given the current emphasis on aquaculture diversification, stress-related indicators broadly applicable across species are needed. Utilising an interspecific comparative transcriptomic (RNAseq) approach, we compared gill gene expression responses of Atlantic salmon (Salmo salar) and Nile tilapia (Oreochromis niloticus) to rearing density and Saprolegnia parasitica infection. Salmon reared at high-density showed increased expression of stress-related markers (e.g. c-fos and hsp70), and downregulation of innate immune genes. Upon pathogen challenge, only salmon reared at low density exhibited increased expression of inflammatory interleukins and lymphocyte-related genes. Tilapia immunity, in contrast, was impaired at low-density. Using overlapping gene ontology enrichment and gene ortholog analyses, we found that density-related stress similarly impacted salmon and tilapia in key immune pathways, altering the expression of genes vital to inflammatory and Th17 responses to pathogen challenge. Given the challenges posed by ectoparasites and gill diseases in fish farms, this study underscores the importance of optimal rearing densities for immunocompetence, particularly for mucosal immunity. Our comparative transcriptomics analyses identified density stress impacted immune markers common across different fish taxa, providing key molecular targets with potential for monitoring and enhancing aquaculture resilience in a wide range of farmed species.

Immune response of teleost fish to helminth parasite infection.

Fish immune systems have become the subject of several studies due to the growing development of aquaculture and fisheries, and the demand for healthy produce for human consumption. Among the parasites responsible for diseases in fish farming, helminths stand out because they cause infections in farmed fish and decrease food conversion, zootechnical performance and meat quality. In the present review, the components that participate in the innate and adaptive immune responses of teleost fish that have so far been described are presented in order to summarize the defenses that these hosts have recourse to, in combating different groups of helminth parasites.

Occupational injuries and diseases in fish farming in Finland 1996-2015.

The agriculture, forestry and fishing industry sector has high rates of occupational injuries. Fishing has globally particularly high occupational fatality rates, but injuries and illnesses to people working in its sub-sectors, aquaculture and fish farming, are not well understood. This study characterised injuries and occupational diseases to fish farmers and people employed on fish farms in Finland using national employment and accident insurance (workers' compensation) data. A total of 392 injuries and 18 occupational diseases were compensated during 1996 to 2015 to fish farmers and people employed on fish farms in Finland. The average injury rate was 3.2 injuries per 100 employed persons with no significant trend over time. Two of the injuries were fatal. Injured persons were primarily male (87.2%), in 45-54 year age group (39.1%), and working in coastal areas (49%). Com- mon injury characteristics included: incident type: slips, trips, and falls (37%); location: building, structure or ground level surface (28%); injured body part: hand or finger (25%); type of injury: dislocation, sprain, strain (35%); and lost worktime: 1 to 2 weeks (26.9%). Seven out of 18 occupational diseases occurred to women, most resulting in cumulative trauma from fish processing. The injury rate in fish farming corresponds to rate in all industries combined in Finland, and is higher than the rate in available Nordic statistics on fish farming. Fish farming injuries could be reduced further by slip resistant surfaces, protection of hands and fingers and ergonomics in processing.

Investigation of farmed Nile tilapia health through histopathology

Confinement is a stressful practice for fish, which can culminate in tissue damage and production losses. Histopathological examination is a technique capable of forthcoming the normal and pathological conditions in fish. It reflects the animal's health and welfare, being able to apply measures to mitigate the stress and diseases in fish farming. This study evaluated the health status of cultured Nile tilapia using histopathological examination as a tool. Fragments of gills, liver, heart and spleen of 60 tilapias from fish farms in southern Brazil were collected and fixed. All crops were free of sanitary problems and fish were clinically healthy. This study showed a positive correlation between Trichodina species, protozoans and hyperplasic epithelium in the secondary lamellae and lamellar fusion, as well as the role of parasites in the inflammatory response in tilapia gills. Nonetheless, alterations such as hyperplasia of interlamellar epithelium were persistent even in non-parasitized animals, suggesting being an adaptation to the confinement environment. The presence of melanomacrophage centers in the liver and spleen were characteristic of the chronic stress that the cultured fish are exposed to. Histological findings such as epitheliocystis in the gills and bacterial colonies in the liver, spleen and heart, showed that even with absence of mortality, bacteremia were present in healthy farmed fish, as well as the parasitic diseases culminating in mixed infections. This study presented unprecedented results on tissue changes in farmed tilapia, serving as an assistance for what can be considered normal in the histopathological examination in farmed fish. Fish herein used did not present any production loss and did not have the relative condition factor (Kn) influenced by the changes, indicating a good health status. Thus, this study reports the first occurrence of epitheliocystis in tilapia gills grown in southern Brazil.

Uso de extratos de plantas e suas propriedades profiláticas ou terapêuticas na produção de peixes

Explore the studies on natural products in fish farms becomes necessary because the market is increasingly demanding about the quality and sustainability of the product. The fish farmers are adapting to the new market parameters as quality, safety and disposal of pollutants, such as antibiotics and carcinogens used for aquaculture activities. This literature review aims to evaluate a number of plant extracts and their prophylactic or therapeutic properties for some diseases in fish farming with the aim providing scientific and technological advances for the sector. Plant extracts, such as the garlic essential oil, are widely studied because they contain prophylactic or therapeutic properties for some diseases in fish farming.

Florfenicol depletion in edible tissue of rainbow trout, Oncorhynchus mykiss (Walbaum), and sea bream, Sparus aurata L.

An increase in fish production has consequently brought an increase in infectious diseases in fish farms. The use of chemotherapic drugs is the most effective instrument against common bacterial agents. The number of registered drugs for use in aquaculture is limited and often veterinary practitioners resort to the off-label use of chemotherapic agents authorized for different food-producing animal species. Florfenicol is well known for its outstanding effect against various pathogenic bacteria affecting fish, and therefore, it may be a useful drug for off-label use in aquaculture. The aim of this study was to evaluate the depletion of florfenicol and its major metabolite, florfenicol amine, from the edible tissue of two fish species, rainbow trout and sea bream, following treatment with medicated feed at a dosage of 10mgkg(-1) of bwday(-1) , for 10 consecutive days. At prefixed time points after the end of administration (0.25, 1, 2, 3, 4, 6, 7, 10, 14 and 21days after treatment), edible tissues (muscle plus adherent skin) from 15 individuals in each group were collected and analysed by HPLC, to determine concentration of the drug in the tissue. On the basis of the obtained concentrations, withdrawal times of florfenicol in the two species were calculated. The results indicate that a drug withdrawal time of 500°C-day, as established by Directive 2004/28/EC, for off-label drug use is more than satisfactory to guarantee the healthiness of fish products against the risk of drug residues.

Selected parasitosis in cultured and wild fish

While intensive aquaculture has and will continue to supply the ever growing population with highly nutritious protein, it also comes with problems which include more frequent outbreaks of diseases in fish farms and transmission of diseases between farmed and wild fish. We have selected four Phyla of economically important fish parasites for our present discussion—a haemoflagellate ( Cryptobia salmositica), a microsporidian, ( Loma salmonae) , a monogenean ( Gyrodactylus salaries) and two copepods ( Lepeophtheirus salmonis, Caligus rogercresseyi). This review consists of two parts with a brief description of each parasite and its biology related to transmission, followed by discussions on epizootic outbreaks in both wild and farmed fish, interactions between wild and farmed fish, and disease prevention and control.

Occurrence of Infectious Fish Diseases in Fish Farms in Northern Finland

A total of 47 fish located in 10 lake and river systems in northern Finland were examined for furunculosis, enteric redmouth diseases (ERM), viral fish diseases and the parasite Gyrodactylus salaris. Furunculosis was found in 2 fish farms in different watercourses, ERM in 8 fish farms in 3 watercourses and viral diseases were not found at all. G. salaris was looked for only in salmon and rainbow trout and was found in both species in 3 farms belonging to 2 watercourses.

Diagnosis and control of diseases in fish farms

Over the years, veterinary science has been increasingly successful in diagnosing and treating disease in the common farm animals. Now, however, a new challenge has arisen. The explosive growth in aquaculture since the end of the Second World War — annual production now exceeds 10 million tonnes — demands the development of equally sophisticated methods for dealing with the diseases of farmed fish. This article reviews the progress that has been made and the prospects for the future.