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Fish & Shellfish Immunology Nov 2023Aquatic animal health management has become a crucial component in the goal of increasing catfish aquaculture productivity. Additionally, hybrid catfish (Clarias...
Effects of the combination of chitosan and Acinetobacter KU011TH on the growth and health performances and disease resistance of juvenile hybrid catfish (Clarias gariepinus × C. macrocephalus).
Aquatic animal health management has become a crucial component in the goal of increasing catfish aquaculture productivity. Additionally, hybrid catfish (Clarias gariepinus × C. macrocephalus) has been promoted as a highly profitable freshwater fish in Asia. Interestingly, the crucial diseases induced by Aeromonas hydrophila have been reported to greatly impede catfish production. To overcome this challenge, the aim was to investigate the effects of the oral administration of potentially synbiotic chitosan (CH) and Acinetobacter KU011TH (AK) on the growth performance, immunological responses, and disease resistance of hybrid catfish against A. hydrophila. The control group was fed a basal diet (A), the diet fed to treatment group B was supplemented with 20 mL of CH/kg diet (B), and the experimental feed fed to groups C-D was mixed with 1 × 10, 1 × 10 and 1 × 10 CFU/mL AK coated with 20 mL of CH/kg diet. Five different groups of juvenile hybrid catfish were continuously fed the 5 formulated feeds for 4 weeks. The results revealed that all tested feeds did not significantly enhance the hybrid catfish's average daily gain, specific growth rate, feed conversion ratio, hematocrit and erythrocyte counts. Interestingly, the application of CH and AK significantly increased the leukocyte counts, respiratory burst, lysozyme activity, alternative complement pathway hemolytic activity, and bactericidal activity (P < 0.05). The expression levels of the immune-related genes in the whole blood, head kidney, and spleen were significantly increased after CH-AK application (P < 0.05), but this finding was not observed in the liver (P > 0.05). Additionally, after 14 days of A. hydrophila peritoneal injection, the fish in group C showed significantly higher survival rates of approximately 70.0 % compared with the control fish in groups B, D, and E (52.5 %, 40.0 %, 45.0 %, and 45.0 %, respectively) (P < 0.05). These results collectively suggest that short-term application of the diet fed to group C effectively boosted the immune responses and disease resistance of hybrid catfish against A. hydrophila.
Topics: Animals; Disease Resistance; Chitosan; Catfishes; Dietary Supplements; Diet; Fish Diseases; Animal Feed; Aeromonas hydrophila; Gram-Negative Bacterial Infections
PubMed: 37863127
DOI: 10.1016/j.fsi.2023.109177 -
Ecotoxicology and Environmental Safety Oct 2023Gut microbiota plays a critical role in regulating the health and adaptation of wildlife. However, our understanding of how exposure to environmental heavy metals...
Gut microbiota plays a critical role in regulating the health and adaptation of wildlife. However, our understanding of how exposure to environmental heavy metals influences the gut microbiota of wild birds, particularly during the vulnerable and sensitive nestling stage, remains limited. In order to investigate the relationship between heavy metals and the gut microbiota, we analyzed the characteristics of gut microbiota and heavy metals levels in tree sparrow nestlings at different ages (6, 9 and 12-day-old). The study was conducted in two distinct areas: Baiyin (BY), which is heavily contaminated with heavy metals, and Liujiaxia (LJX), a relatively unpolluted area. Our result reveled a decrease in gut microbiota diversity and increased inter-individual variation among nestlings in BY. However, we also observed an increase in the abundance of bacterial groups and an up-regulation of bacterial metabolic functions associated with resistance to heavy metals toxicity in BY. Furthermore, we identified a metal-associated shift in the relative abundance of microbial taxa in 12-day-old tree sparrow nestlings in BY, particularly involving Aeromonadaceae, Ruminococcaceae and Pseudomonadaceae. Moreover, a significant positive correlation was found between the body condition of tree sparrow nestlings and the abundance of Bifidobacteriaceae in BY. Collectively, our findings indicate that the gut microbiota of tree sparrow nestlings is susceptible to heavy metals during early development. However, the results also highlight the presence of adaptive responses that enable them to effectively cope with environmental heavy metal pollution.
Topics: Animals; Sparrows; Gastrointestinal Microbiome; Metals, Heavy; Environmental Pollution; Animals, Wild
PubMed: 37716068
DOI: 10.1016/j.ecoenv.2023.115480 -
Frontiers in Cellular and Infection... 2023is an important pathogen that mainly harms aquatic animals and exhibits resistance to a variety of antibiotics. This study investigated the effect of...
BACKGROUND
is an important pathogen that mainly harms aquatic animals and exhibits resistance to a variety of antibiotics. This study investigated the effect of epigallocatechin-3-gallate (EGCG) on the virulence factors of and its impact on adhesion, invasion, and cytotoxicity in Caco-2 cells. The potential mechanism of antibacterial activity of EGCG was investigated by transcriptomic analysis.
RESULTS
EGCG not only inhibited the production of biofilm, hemolytic activity, motility, and protease activity of , but also reduced its adhesion, invasion, and cytotoxicity in Caco-2 cells. Transcriptomic analysis indicated that the antimicrobial activity of EGCG may be achieved by weakening the chemotaxis and stress response of the bacteria, as well as inhibiting the TonB system. Animal studies demonstrated that EGCG can significantly improve the survival rate and organs damage of zebrafish infected with .
CONCLUSION
EGCG would be a potential alternative drug for the prevention and treatment of infections by anti-virulence mechanism.
Topics: Animals; Humans; Aeromonas hydrophila; Zebrafish; Caco-2 Cells; Transcriptome; Anti-Bacterial Agents; Gram-Negative Bacterial Infections
PubMed: 37868352
DOI: 10.3389/fcimb.2023.1271448 -
Aquatic Toxicology (Amsterdam,... Jun 2024Excessive antibiotic use has led to the spread of antibiotic resistance genes (ARGs), impacting gut microbiota and host health. However, the effects of antibiotics on...
Metagenomic and transcriptomic analysis revealing the impact of oxytetracycline and ciprofloxacin on gut microbiota and gene expression in the Chinese giant salamander (Andrias davidianus).
Excessive antibiotic use has led to the spread of antibiotic resistance genes (ARGs), impacting gut microbiota and host health. However, the effects of antibiotics on amphibian populations remain unclear. We investigated the impact of oxytetracycline (OTC) and ciprofloxacin (CIP) on Chinese giant salamanders (Andrias davidianus), focusing on gut microbiota, ARGs, and gene expression by performing metagenome and transcriptome sequencing. A. davidianus were given OTC (20 or 40 mg/kg) or CIP (50 or 100 mg/kg) orally for 7 days. The results revealed that oral administration of OTC and CIP led to distinct changes in microbial composition and functional potential, with CIP treatment having a greater impact than OTC. Antibiotic treatment also influenced the abundance of ARGs, with an increase in fluoroquinolone and multi-drug resistance genes observed post-treatment. The construction of metagenome-assembled genomes (MAGs) accurately validated that CIP intervention enriched fish-associated potential pathogens Aeromonas hydrophila carrying an increased number of ARGs. Additionally, mobile genetic elements (MGEs), such as phages and plasmids, were implicated in the dissemination of ARGs. Transcriptomic analysis of the gut revealed significant alterations in gene expression, particularly in immune-related pathways, with differential effects observed between OTC and CIP treatments. Integration of metagenomic and transcriptomic data highlighted potential correlations between gut gene expression and microbial composition, suggesting complex interactions between the host gut and its gut microbiota in response to antibiotic exposure. These findings underscore the importance of understanding the impact of antibiotic intervention on the gut microbiome and host health in amphibians, particularly in the context of antibiotic resistance and immune function.
Topics: Animals; Oxytetracycline; Gastrointestinal Microbiome; Ciprofloxacin; Urodela; Anti-Bacterial Agents; Transcriptome; Metagenome; Metagenomics; Gene Expression Profiling; Water Pollutants, Chemical; Aeromonas hydrophila; Gene Expression Regulation
PubMed: 38718521
DOI: 10.1016/j.aquatox.2024.106925 -
Journal of Fish Diseases Feb 2024Aeromonas septicemia still represents a serious challenge facing the global aquaculture sector. In the present study, Aeromonas caviae and A. veronii were isolated from...
Aeromonas septicemia still represents a serious challenge facing the global aquaculture sector. In the present study, Aeromonas caviae and A. veronii were isolated from four diseased European seabass (Dicentrarchus labrax) farms experiencing a high mortality rate. Diseased fish showed haemorrhages on the external body surface with exophthalmia, cataracts, scale desquamation, skin ulcers and fin erosions. The most common post-mortem findings were congested internal organs, particularly the liver and posterior kidney. Twenty-eight A. Veronii and 11 A. caviae isolates were identified biochemically by the Vitek 2 system and then confirmed by PCR and phylogenetic analysis. Hemolysin (hlyA) and aerolysin (aer) were the most abundant virulence genes in the recovered isolates, followed by cytotoxic enterotoxin (act) and heat-stable enterotoxin (ast). A. caviae was more virulent than A. veronii for D. labrax fingerlings as LD ranging between (>1 × 10 -6.2 × 10 ) for A. veronii and (2.9 × 10 -8.3 × 10 ) for A. caviae. The sensitivity test indicated the effectiveness of norfloxacin, doxycycline and oxytetracycline against the tested isolates. Serum cortisol significantly increased in the infected groups, while catalase and glutathione peroxidase activities significantly decreased at 2 days post-infection (DPI) and then increased at 6 DPI. The presence of virulence genes was associated with bacterial pathogenicity expressed in fish mortality rate. Virulence genes also drastically affect cortisol levels more than catalase and glutathione peroxidase levels.
Topics: Animals; Aeromonas; Virulence; Bass; Catalase; Genotype; Phylogeny; Hydrocortisone; Fish Diseases; Enterotoxins; Glutathione Peroxidase; Gram-Negative Bacterial Infections
PubMed: 37881027
DOI: 10.1111/jfd.13878 -
Scientific Reports Jul 2023The proliferation of antibiotic-resistant bacteria and antimicrobial resistance is a pressing public health challenge because of their possible transfer to humans via...
Isolation and genotypic characterization of extended-spectrum beta-lactamase-producing Escherichia coli O157:H7 and Aeromonas hydrophila from selected freshwater sources in Southwest Nigeria.
The proliferation of antibiotic-resistant bacteria and antimicrobial resistance is a pressing public health challenge because of their possible transfer to humans via contact with polluted water sources. In this study, three freshwater resources were assessed for important physicochemical characteristics as well as heterotrophic and coliform bacteria and as potential reservoirs for extended-spectrum beta-lactamase (ESBL) strains. The physicochemical characteristics ranged from 7.0 to 8.3; 25 to 30 °C, 0.4 to 93 mg/L, 0.53 to 8.80 mg/L and 53 to 240 mg/L for pH, temperature, dissolved oxygen (DO), biological oxygen demand (BOD) and total dissolved solids, respectively. The physicochemical characteristics mostly align with guidelines except for the DO and BOD in some instances. Seventy-six (76) Aeromonas hydrophila and 65 Escherichia coli O157: H7 isolates were identified by preliminary biochemical analysis and PCR from the three sites. Among these, A. hydrophila displayed higher frequencies of antimicrobial resistance, with all 76 (100%) isolates completely resistant to cefuroxime and cefotaxime and with MARI ≥ 0.61. The test isolates showed more than 80% resistance against five of the ten test antimicrobials, with resistance against cefixime, a cephalosporin antibiotic being the highest at 95% (134/141). The frequency of the detection of the resistance genes in the A. hydrophila isolates generally ranged between 0% (bla) and 26.3% (bla), while the frequency of detection among the E. coli O157:H7 isolates ranged between 4.6% (bla) and 58.4% (bla). Our findings indicate that the distribution of antibiotic-resistant bacteria with diverse ESBL-producing capabilities and virulence genes in freshwater sources potentially threatens public health and the environment.
Topics: Humans; Escherichia coli O157; Aeromonas hydrophila; Nigeria; beta-Lactamases; Anti-Bacterial Agents; Escherichia coli Infections; Anti-Infective Agents
PubMed: 37400612
DOI: 10.1038/s41598-023-38014-y -
Fish & Shellfish Immunology Aug 2023The complement system is essential to host defense, but its excessive activation caused by severe pathogen invasion is a driving force in adverse inflammatory. The...
The complement system is essential to host defense, but its excessive activation caused by severe pathogen invasion is a driving force in adverse inflammatory. The binding of complement component 5a (C5a) and complement component 5a receptor 1 (C5aR1) is the key to trigger complement-mediated inflammatory response in mammals. However, the role of C5a-C5aR1 axis in fish immune response remains obscure. In this study, the role of C5a-C5aR1 axis of zebrafish (Danio rerio) after serious infection with Aeromonas hydrophila was investigated. C5a and C5aR1 of zebrafish were cloned, with CDS sequences of 228 and 1041 bp, respectively, and they were widely expressed in various tissues with the highest expression in the liver and spleen, respectively. The survival of zebrafish was closely correlated to the dose of A. hydrophila. The cytokine storm occurred at high concentrations of A. hydrophila infection. At 24 h post infection (hpi), the expression of C5a and C5aR1 in the spleen increased 26.8-fold and 9.9-fold in treatment group 1 (TG1, 3.0 × 10 CFU/mL) (P < 0.01), and 4.7-fold and 3.4-fold in treatment group 2 (TG2, 1.0 × 10 CFU/mL) (P < 0.05), respectively. Correspondingly, proinflammatory cytokines interleukin-1β (IL-1β), interleukin-8 (IL-8), and interleukin-17 (IL-17) were positively correlated to C5a and C5aR1 at mRNA and protein expression levels. The expression of IL-1β was significantly increased in the spleen at 6 hpi, with a 599.2-fold and 203.2-fold upregulation in TG1 and TG2 (P < 0.001), respectively. Moreover, after inhibition of C5a-C5aR1 binding treated with C5aR1 antagonist (W-54011), zebrafish showed lower expression of C5a, C5aR1, and cytokines, less intestinal damage, and significantly enhancement of survival (P < 0.05) after A. hydrophila challenge. This study revealed that the inflammatory effect of C5a was achieved by binding to C5aR1 in zebrafish, providing novel insights into using C5a-C5aR1 axis as an effective target to reduce bacterial inflammation and disease in fish.
Topics: Animals; Zebrafish; Aeromonas hydrophila; Complement C5a; Inflammation; Cytokines; Mammals
PubMed: 37271327
DOI: 10.1016/j.fsi.2023.108873 -
BMC Microbiology Aug 2023In recent years, the demand for innovative antimicrobial agents has grown, considering the growing problem of antibiotic resistance in aquaculture. Adult Apis mellifera...
BACKGROUND
In recent years, the demand for innovative antimicrobial agents has grown, considering the growing problem of antibiotic resistance in aquaculture. Adult Apis mellifera honeybees' gut represents an outstanding habitat to isolate novel lactic acid bacteria (LAB) able to produce prominent antimicrobial agents.
METHODS
In the current study, twelve LAB were isolated and purified from the gut of adult Apis mellifera. The isolates were screened for exopolysaccharide (EPS) production. The most promising isolate BE11 was identified biochemically and molecularly using 16 S rRNA gene sequence analysis as Enterococcus sp. BE11 was used for the mass production of EPS. The partially purified BE11-EPS features were disclosed by its physicochemical characterization. Moreover, the antimicrobial activity of BE11 cell free supernatant (CFS) and its EPS was investigated against some fish pathogens namely, Pseudomonas fluorescens, Streptococcus agalactiae, Aeromonas hydrophila, Vibrio sp. and Staphylococcus epidermidis using well-cut diffusion method.
RESULTS
The physicochemical characterization of BE11-EPS revealed that the total carbohydrate content was estimated to be ~ 87%. FTIR and NMR analysis ascertained the presence of galactose and glucose residues in the EPS backbone. Moreover, the GC-MS analysis verified the heterogeneous nature of the produced BE11-EPS made up of different monosaccharide moieties: galactose, rhamnose, glucose, arabinose sugar derivatives, and glucuronic acid. BE11 CFS and its EPS showed promising antimicrobial activity against tested pathogens as the inhibition zone diameters (cm) ranged from 1.3 to 1.7 and 1.2-1.8, respectively.
CONCLUSION
The bee gut-resident Enterococcus sp. BE11, CFS, and EPS were found to be promising antimicrobial agents against fish pathogens and biofilm producers affecting aquaculture. To the best of our knowledge, this is the first study to purify and make a chemical profile of an EPS produced by a member of the bee gut microbiota as a potential inhibitor for fish pathogens.
Topics: Bees; Animals; Galactose; Anti-Bacterial Agents; Aeromonas hydrophila; Enterococcus; Fishes; Glucose; Lactobacillales
PubMed: 37612642
DOI: 10.1186/s12866-023-02977-9 -
Genes Jun 2023To further investigate the immune response of against , comparative transcriptomic analyses of the hepatopancreas were conducted on challenge and control groups at 6,...
To further investigate the immune response of against , comparative transcriptomic analyses of the hepatopancreas were conducted on challenge and control groups at 6, 12, and 24 h post-infection (hpi), independently. A total of 51,707 high-quality unigenes were collected from the RNA-seq data, and 8060 differentially expressed genes (DEGs) were discovered through paired comparisons. Among the three comparison groups, a KEGG pathway enrichment analysis showed that 173 immune-related DEGs were considerably clustered into 28 immune-related pathways, including the lysosome, the phagosome, etc. Moreover, the expression levels of the four key immune-related genes (, , , and ) were evaluated at various stages following post-infection in the hepatopancreas, hemolymph, and gills. Both and genes were highly up-regulated in all three tissues at 6 hpi with ; was up-regulated in the hepatopancreas and hemolymph but down-regulated in the gill at 6 hpi, and was up-regulated in hemolymph and gill, but down-regulated in the hepatopancreas at 6 hpi. These findings lay the groundwork for understanding the immune mechanism of after contracting .
Topics: Animals; Aeromonas veronii; Palaemonidae; Glycogen Synthase Kinase 3 beta; I-kappa B Kinase; Transcriptome; Immunity
PubMed: 37510289
DOI: 10.3390/genes14071383 -
Cells Sep 2023Interleukin (IL) 21 is a pleiotropic cytokine that plays an important role in regulating innate and adaptive immune responses. In fish, the biological functions and cell...
Interleukin (IL) 21 is a pleiotropic cytokine that plays an important role in regulating innate and adaptive immune responses. In fish, the biological functions and cell source of IL-21 remain largely unknown. In this study, we performed qRT-PCR, Western blotting and immunofluorescent microscopy to examine the expression of IL-21 at the mRNA and protein levels. We found that expression was induced in the primary head kidney leukocytes of grass carp () by heat-inactivated () and LPS and in tissues after infection with . Recombinant IL-21 protein produced in the CHO-S cells was effective in elevating the expression of antibacterial genes, including and , and, interestingly, inhibited the NF-κB signaling pathway. Furthermore, we investigated the response of the IL-21 expressing cells to infection. Immunofluorescent assay showed that IL-21 protein was detected in the CD3γ/δ T cells and was markedly accumulated in the anterior, middle and posterior intestine. Collectively, the results indicate that IL-21 plays an important role in regulating the intestinal inflammation induced by bacterial infection in grass carp.
Topics: Animals; Aeromonas hydrophila; Carps; Interleukins; Inflammation
PubMed: 37759501
DOI: 10.3390/cells12182276