RÉSUMÉ
Heavy metal contamination of aquatic environments adversely affects the health of aquatic organisms and consumption of fish contaminated with heavy metals poses serious health risks to humans. Among various strategies, probiotics (living microorganisms known to have beneficial effects on the host), which have been extensively applied in the aquaculture industry, could be helpful for heavy metal detoxification and remediation. Several probiotics, including Lactobacillus strains, exhibit heavy metal binding, high heavy metal tolerance, and other beneficial characteristics for the host. Notably, numerous probiotics have been reported to bind heavy metals and excrete them from the host. Various probiotic strains (Lactobacillus, Bacillus, Lactococcus, etc.) show beneficial effects in alleviating heavy metal toxicity in cultured fish species. Certain probiotic bacteria reduce the absorption and bioavailability of heavy metals by enhancing heavy metal detoxification and sequestration while preserving gut barrier function. This review summarises the toxic effects of selected heavy metals on the health of farmed fish and discusses the role of probiotic strains in remediating the consequential exposure-induced immune toxicity and oxidative stress. Moreover, we discussed the protective strategies of probiotics against heavy metal accumulation in various tissues and gut dysbiosis in fish to alleviate heavy metal toxicity in fish farming, thereby promoting a sustainable blue economy worldwide.
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Despite the precarious state of marine turtles as a highly endangered species, our understanding of their diseases remains limited. This case report presents a detailed pathological investigation of spirorchiidiasis, a blood fluke infection that poses a substantial threat to marine turtles. This retrospective study examined three cases of spirorchiid-infected sea turtles, specifically, green sea turtles stranded on Jeju Island, South Korea. Premortem examination of the three spirorchiid-infected green sea turtles demonstrated nonspecific clinical symptoms; blood analysis revealed dehydration, malnutrition, and anemia. Computed tomography scans provided insights into severe pulmonary and extrapulmonary manifestations, including the mass present in the joint region. Post-mortem examinations consistently indicated severe lung lesions and systemic manifestations, with histopathological examination confirming the presence of spirorchiid ova across various organs. Despite the global prevalence of spirorchiidiasis in sea turtles, disease severity varies regionally. This report provides a detailed demonstration of the pathology of spirorchiidiasis in sea turtles from Northeast Asia.
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Erwinia amylovora, the primary causative agent of blight disease in rosaceous plants, poses a significant threat to agricultural yield worldwide, with limited effective countermeasures. The emergence of sustainable alternative agents such as bacteriophages is a promising solution for fire blight that specifically targets Erwinia. In this study, we isolated pEp_SNUABM_01 and pEa_SNUABM_55 from a South Korean apple orchard soil, analyzed their genomic DNA sequences, and performed a comprehensive comparative analysis of Hena1 in four distinct sections. This study aimed to unveil distinctive features of these phages, with a focus on host recognition, which will provide valuable insights into the evolution and characteristics of Henunavirus bacteriophages that infect plant pathogenic Erwinia spp. By elucidating the distinct genomic features of these phages, particularly in terms of host recognition, this study lays a foundation for their potential application in mitigating the risks associated with fire blight in Rosaceae plants on a global scale.
Sujet(s)
Bactériophages , Erwinia amylovora , Génome viral , Maladies des plantes , Erwinia amylovora/virologie , Erwinia amylovora/génétique , Maladies des plantes/virologie , Maladies des plantes/microbiologie , Bactériophages/génétique , Bactériophages/classification , Bactériophages/isolement et purification , Phylogenèse , Spécificité d'hôte , Génomique , Malus/microbiologie , Malus/virologie , Microbiologie du solRÉSUMÉ
BACKGROUND: Human fishing activities have significantly affect environmental concern for marine ecosystems, conservation of marine mammals, and human health. Coastal cetaceans are highly vulnerable to ingestion of fishing gear, bycatching, or entanglement, all of which can be fatal for these animals. In particular, certain coastal dolphins and porpoises are heavily impacted by fishing gear such as angling gear or stownet, as their food often overlap with the target fish species of human fisheries. CASE PRESENTATION: This study presents a case of an Indo-Pacific finless porpoise (Neophocaena phocaenoides) beached on the coast of Jeju Island, Republic of Korea, with ingestion of fishing gear and severe Anisakis infection. Although this species inhabits waters ranging from the Persian Gulf to Taiwan, several stranded carcasses have been reported on Jeju Island in recent years. Post-mortem computed tomography revealed a bundle of four fishing hooks in the forestomach, along with nylon lines and steel lines with connectors, which were assumed to be angling gear for Jeju hairtail (Trichiurus lepturus). Further necroscopic investigation revealed that the forestomach contained a large number of Anisakis spp. (Nematoda: Anisakidae). Histological examination revealed a thickened forestomach wall with pinpoint and volcanic ulcerations, a thickened layer of stratified squamous epithelium, and infiltrated stroma in the squamous epithelium. CONCLUSIONS: This study emphasizes the urgent need to address the impact of fishing activities on marine mammals, marine litter pollution, and the bycatch problem in Korean seawater. In addition, the occurrence of N. phocaenoides in seawater around Jeju Island should be raised in future geographical ecology or veterinary pathology studies and when its distribution is updated.
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Anisakiase , Anisakis , Marsouins , Animaux , Marsouins/parasitologie , République de Corée , Anisakiase/médecine vétérinaire , Anisakiase/parasitologie , Anisakis/isolement et purification , Pêcheries , Tomodensitométrie/médecine vétérinaire , Mâle ,RÉSUMÉ
Heat-killed probiotics offer an alternative approach to enhance growth and disease resistance in farmed fish. In this study, we isolated Lactiplantibacillus plantarum VSG3 from the gut of Labeo rohita to investigate the effects of heat-killed L. plantarum (HK-LP) on the health and growth performance of Cyprinus carpio fingerlings. Different concentrations of HK-LP (0, 50, 100, 200, 300, and 400 mg/kg) were administered to the fish, followed by a challenge with Aeromonas hydrophila after 8 weeks of feeding. Notably, the LP200 group exhibited significantly improved percentage weight gain and specific growth rate, accompanied by the lowest feed conversion ratio. Post-challenge survival rates were considerably enhanced in the LP200 group, reaching 60.65%. Moreover, serum analysis indicated significantly higher levels of total protein and albumin in the LP200 group than in the control group. Although HK-LP had no substantial impact on certain serum parameters (glucose, total cholesterol, cortisol, and alanine aminotransferase), aspartate aminotransferase levels were considerably low in the LP200 group. Intestinal protease and trypsin activities significantly increased in the LP200 group, while no significant changes were observed in lipase and amylase activities post-pathogen challenge. Serum immunological indices, including lysozyme, alternative complement pathway, and phagocytic activity, improved considerably in the LP200 group. Additionally, serum antioxidant enzyme activities (superoxide dismutase [SOD], glutathione peroxidase [GPx], catalase [CAT], and myeloperoxidase) were significantly elevated in the LP200 group, while malondialdehyde level was reduced. Gene expression analysis in liver tissue indicated strong upregulation of antioxidant-related genes (SOD, CAT, nuclear factor erythroid 2 [NFE2]-related factor 2 [Nrf2], Kelch-like ECH-associated protein 1[Keap1]) in the LP100 and LP200 groups. Pro-inflammatory cytokines (IL-1ß and TNF-α) were considerably downregulated in the kidneys of the LP200 post-challenged fish, although the anti-inflammatory cytokine IL-10 showed an increased expression. Quadratic regression analysis identified the optimal dietary HK-LP level for maximizing growth and immune performance (200.381-270.003 mg/kg). In summary, our findings underscore the potential of HK-LP as a valuable dietary supplement for enhancing carp aquaculture, particularly at the appropriate concentration.
Sujet(s)
Aeromonas hydrophila , Aliment pour animaux , Antioxydants , Carpes (poisson) , Régime alimentaire , Maladies des poissons , Infections bactériennes à Gram négatif , Probiotiques , Animaux , Probiotiques/administration et posologie , Probiotiques/pharmacologie , Infections bactériennes à Gram négatif/immunologie , Infections bactériennes à Gram négatif/médecine vétérinaire , Carpes (poisson)/immunologie , Carpes (poisson)/croissance et développement , Aliment pour animaux/analyse , Maladies des poissons/immunologie , Régime alimentaire/médecine vétérinaire , Aeromonas hydrophila/physiologie , Antioxydants/métabolisme , Immunité innée , Lactobacillus plantarum/composition chimique , Température élevée , Expression des gènes , Compléments alimentaires/analyse , Répartition aléatoire , Résistance à la maladieRÉSUMÉ
INTRODUCTION: Spinal deformities, including kyphoscoliosis, have been consistently documented in cetaceans. However, the majority of reported cases of kyphoscoliosis in cetaceans pertain to bottlenose dolphins, with limited information on its occurrence in narrow-ridged finless porpoise (NFP) (Neophocaena asiaeorientalis). MATERIALS AND METHODS: In November 2021, two deceased NFPs were discovered stranded on the shores of the Republic of Korea. As part of the pioneer stranded cetacean imaging programme in the Republic of Korea, both carcasses underwent post-mortem computed tomography (PMCT), revealing congenital and degenerative traumatic kyphoscoliosis, respectively. RESULTS: Although kyphoscoliosis may not have directly caused the demise of these individuals, it is hypothesized that the reduced spinal range of motion and mobility associated with kyphoscoliosis may have contributed to their deaths. CONCLUSION: This case report presents the first documented cases of kyphoscoliosis in two NFPs stranded in Korean waters, utilizing PMCT as an efficient methodology for assessing skeletal abnormalities in cetaceans.
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Marsouins , Animaux , /médecine vétérinaire , République de CoréeRÉSUMÉ
In this case report, we present a rare occurrence of a narrow-ridged finless porpoise (Neophocaena asiaeorientalis sunameri), discovered on the coast of Jeju Island, Republic of Korea, that was afflicted with adhesive bowel obstruction (ABO), a life-threatening condition that has scarcely been reported in cetaceans. Diagnosis of ABO was confirmed via radiological and clinical assessments. Post-mortem computed tomography and necropsy revealed ABO between two loops of the jejunum at the L8 level. The mesenteric tissue covering the intestinal lesion was severely thickened with increased tension. Both bowel loops were fixed to the mesentery and acutely angulated, leading to asymmetrical thickening of the cross-sectional bowel walls. The intestinal lumen was stenosed because of pressure from the firm mesenteric band, and no fecal matter was observed in the lumen of the posterior bowel or rectum. Calcified nodules were detected, and histological analysis suggested parasitic or suspected post-parasitic infections. The primary cause of the intestinal lesions is presumed to be a reaction related to parasitic infection. However, further investigations would establish a definitive link between parasitic infections and ABO in this species. This case highlights the importance of studying rare medical conditions in wildlife, providing valuable insights into marine mammal health.
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Fire blight is a bacterial disease that affects plants of the Rosaceae family and causes significant economic losses worldwide. Although antibiotics have been used to control the disease, concerns about their environmental impact and the potential to promote antibiotic resistance have arisen. Bacteriophages are being investigated as an alternative to antibiotics; however, their efficacy can be affected by environmental stresses, such as UV radiation. In this study, we optimized the formulation of Erwinia phages to enhance their stability in the field, focusing on improving their UV stability and adsorption using adjuvants. Our results confirmed that 4.5 % polysorbate 80 and kaolin improve phage stability under UV stress, resulting in an 80 % increase in PFU value and improved UV protection efficacy. Adsorption assays also demonstrated that polysorbate 80 and kaolin improved the absorption efficiency, with phages detected in plant for up to two weeks. These findings demonstrate the effectiveness of the auxiliary formulation of Erwinia bacteriophages against environmental stress.
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This study investigated the effects of dietary piperine (PIP) on growth performance, digestive enzymes, serum biochemical parameters, antioxidant and immune responses, and gene expression in Cyprinus carpio challenged with Aeromonas hydrophila. Six diets were prepared with PIP doses of 0, 0.5, 1.0, 2.0, 3.0, and 4.0 g/kg, corresponding with the control, PR50, PR100, PR200, PR300, and PR400, respectively. Fish were challenged with Aeromonas hydrophila after 8 weeks of feeding with the respective diets. Weight gain (PWG) and specific growth rate (SGR) were significantly enhanced, whereas feed conversion ratio (FCR) was lowered in PR200. The cumulative post-challenge survival was improved to 68.43% in the PR200 group compared with 28.08% in the control. Serum total protein and albumin levels were significantly enhanced in the PR200 group compared to the control. However, dietary PIP up to 3 g/kg had no significant effect on serum glucose, cortisol, aspartate aminotransferase, or alkaline phosphatase activities; however, the alanine aminotransferase level was lower (P < 0.05) in the PR200 group than in the control. Intestinal amylase, lipase, and protease activities increased in PR300, and intestinal amylase and lipase increased in the PR100 group (P < 0.05). The serum immunological indices (lysozyme, alternative complement pathway, phagocytic activity, and respiratory burst activity) were higher (P < 0.05) in the PR200 group than in the control group. Serum superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) activities were significantly intensified in PR200-PR300 than in the control group, with the highest activity observed in the PR200 group. Malondialdehyde was significantly lower in the PR200 group than in the control group. Furthermore, SOD, CAT, and Nrf2 expression was strongly upregulated in the liver tissue of the PR200 and PR300 groups compared to that in the control. The transcript levels of pro-inflammatory cytokines viz. IL-1ß and TNF-α were significantly upregulated in the kidneys of the PR100 and PR200 post-challenged. In contrast, the anti-inflammatory cytokine IL-10 was significantly downregulated in the kidneys of PR200. The expression of HSP70 was upregulated only in the PR400. Quadratic regression analysis showed that the optimal dietary PIP level was estimated as 2.07-2.13 g/kg to maximize growth performance. Overall, these results indicate that dietary PIP at an appropriate level can improve immunity, cytokine gene expression, and disease resistance in C. carpio.
Sujet(s)
Antioxydants , Carpes (poisson) , Animaux , Cytokines , Aeromonas hydrophila , Amylases , Régime alimentaire/médecine vétérinaire , Résistance à la maladie , Expression des gènesRÉSUMÉ
This study evaluated the effects of jamun leaf extract (JLE) as a feed supplement on growth performance, haemato-immunological, oxidative stress-related parameters, and cytokine gene expression in Cyprinus carpio challenged with Aeromonas hydrophila.. Diets containing four different JLE concentrations, that is, 0 (basal diet), 5 (JLE5), 10 (JLE10), and 15 g kg-1 (JLE15), were fed to carp (6.17 ± 0.43 g) for eight weeks. Growth performance was significantly higher in JLE10. Haemato-immunological and antioxidant parameters were determined in fish at 48 h post-challenge with A. hydrohila. The cumulative survival was highest in JLE10 (69.69%) 14 days post-challenge. Serum protein (2.18 ± 0.06 g dL-1), lysozyme (32.38 ± 1.2 U mL-1), alternative complement pathway (70.43 ± 1.61 U mL-1), phagocytic activity (21.18 ± 0.48%), respiratory burst activity (0.289 ± 0.09 OD630nm), and immunoglobulin levels (6.67 ± 0.36 U mg mL-1) were significantly higher in JLE10 than in the control. Serum alanine aminotransferase (44.06 ± 1.62 Unit mL-1), aspartate aminotransferase (31.58 ± 1.82 Unit mL-1), and malondialdehyde (2.57 ± 0.26 nmol mL-1) levels were lower in JLE10 than in the control (p < 0.05), whereas myeloperoxidase activity was significantly higher in JLE5 and JLE10 than in the control. Superoxide dismutase levels in the serum were higher (p < 0.05) in JLE5 and JLE10 than in the other groups. Gene expression analysis revealed that the mRNA expression of pro-inflammatory cytokines TNF-α and IL-1ß was upregulated (p < 0.05) in the liver, head-kidney, and intestine of challenged carp in JLE10. The signalling molecule NF-κB p65 was upregulated in lymphoid organs in JLE10 but not in the liver. The anti-inflammatory cytokine IL-10 was significantly downregulated in challenged carp in JLE10 compared with that in the control. Quadratic regression analysis showed that optimal dietary JLE was estimated to be 9.03-10.15 g kg-1 to maximize the growth performance. Results of the present study revealed that dietary JLE at 10 g kg-1 can significantly improve the immunity and disease resistance of C. carpio. Thus, JLE is a promising food additive for carp aquaculture.
Sujet(s)
Carpes (poisson) , Maladies des poissons , Infections bactériennes à Gram négatif , Syzygium , Animaux , Carpes (poisson)/génétique , Carpes (poisson)/métabolisme , Syzygium/génétique , Syzygium/métabolisme , Régime alimentaire/médecine vétérinaire , Compléments alimentaires/analyse , Antioxydants/métabolisme , Cytokines/génétique , Cytokines/métabolisme , Expression des gènes , Extraits de plantes/pharmacologie , Aliment pour animaux/analyse , Aeromonas hydrophila/physiologieRÉSUMÉ
The recent outbreak of blight in pome fruit plants has been a major concern as there are two indistinguishable Erwinia species, Erwinia amylovora and E. pyrifoliae, which cause blight in South Korea. Although there is a strict management protocol consisting of antibiotic-based prevention, the area and the number of cases of outbreaks have increased. In this study, we isolated four bacteriophages, pEp_SNUABM_03, 04, 11, and 12, that infect both E. amylovora and E. pyrifoliae and evaluated their potential as antimicrobial agents for administration against Erwinia-originated blight in South Korea. Morphological analysis revealed that all phages had podovirus-like capsids. The phage cocktail showed a broad spectrum of infectivity, infecting 98.91% of E. amylovora and 100% of E. pyrifoliae strains. The antibacterial effect was observed after long-term cocktail treatment against E. amylovora, whereas it was observed for both short- and long-term treatments against E. pyrifoliae. Genomic analysis verified that the phages did not encode harmful genes such as antibiotic resistance or virulence genes. All phages were stable under general orchard conditions. Collectively, we provided basic data on the potential of phages as biocontrol agents that target both E. amylovora and E. pyrifoliae.
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This study evaluated the effects of Bougainvillea glabra (BG) leaf as a feed supplement on growth, skin mucosal immune parameters, serum oxidative stress, expression of immune-related genes, and susceptibility to pathogen infection in carp Cyprinus carpio. Diets containing four different BG concentrations (g kg-1), i.e., 0 g (basal diet), 20 g (BG20), 30 g (BG30), 40 g (BG40), and 50 g (BG50), were fed to the carp (average weight: 14.03 ± 0.81 g) for 8 weeks. Skin mucosal immunological and serum antioxidant parameters were examined 8 weeks post-feeding. Growth performance was significantly higher in BG40. Among the examined skin mucosal immune parameters, lysozyme (33.79 ± 0.98 U mL-1), protein (6.88 ± 0.37 mg mL-1), immunoglobulin (IgM; 5.34 ± 0.37 unit-mg mL-1), and protease activity (3.18 ± 0.36%) were significantly higher in BG40 than in the control; whereas, there was no significant effect on the alkaline phosphatase level. Among serum immune activity, activities of lysozyme, the alternative complement pathway, and IgM were significantly higher in BG40. Phagocytic, and superoxide dismutase (SOD) activities were higher (P < 0.05) in BG30-BG50. Serum ALT, AST, and MDA levels were lower in BG40 than in the control (P < 0.05). Intestinal enzymatic activities were enhanced in BG40 and BG50 (P < 0.05), except for lipase in BG50. Gene expression analysis revealed that the mRNA expressions of antioxidant genes (SOD, GPx, and Nrf2), an anti-inflammatory gene (IL-10), and IκBα were significantly upregulated in BG40. Conversely, the pro-inflammatory gene IL-1ß and the signaling molecule NF-κB p65 were downregulated in BG40 and BG50, respectively. BG supplementation had no significant effect on TNF-α, TLR22, or HSP70 mRNA expressions. Moreover, fish in BG40 exhibited the highest relative post-challenge survival (67.74%) against Aeromonas hydrophila infection. These results suggested that dietary supplementation with BG leaves at 40 g/kg can significantly improve the growth performance, immune responses, and disease resistance of C. carpio. BG leaves are a promising food additive for carp in aquaculture.
Sujet(s)
Carpes (poisson) , Infections bactériennes à Gram négatif , Animaux , Résistance à la maladie , Carpes (poisson)/métabolisme , Antioxydants/métabolisme , Lysozyme/pharmacologie , Immunité muqueuse , Compléments alimentaires/analyse , Régime alimentaire/médecine vétérinaire , ARN messager/métabolisme , Immunoglobuline M , Feuilles de plante , Superoxide dismutase/pharmacologie , Aliment pour animaux/analyseRÉSUMÉ
Long-term feed route exposure to T-2 toxin was proved to elicit growth retarding effects and induction of oxidative stress and apoptosis in Chinese mitten crab (Eriocheir sinensis). However, no study with a holistic perspective has been conducted to date to further describe the in-depth toxicological mechanism of T-2 toxin in E.sinensis. In this study, an RNA-Sequencing (RNA-seq) was used in this study to investigate the effects of feed supplementation with 0 mg/kg and 4 mg/kg T-2 toxin on the hepatopancreas transcriptome of E.sinensis and establish a hepatopancreas transcriptome library of T-2 toxin chronically exposed crabs after five weeks, where 14 differentially expressed genes (DEGs) were screened out across antioxidant, apoptosis, autophagy, glucolipid metabolism and protein synthesis. The actual expression of all the DEGs (Caspase, ATG4, PERK, ACSL, CAT, BIRC2, HADHA, HADHB, ACOX, PFK, eEFe1, eIF4É, RPL13Ae) was also analyzed by real-time quantitative PCR (RT-qPCR). It was demonstrated that long-term intake of large amounts of T-2 toxin could impair antioxidant enzyme activity, promote apoptosis and protective autophagy, disrupt lipid metabolism and inhibit protein synthesis in the hepatopancreas of E.sinensis. In conclusion, this study explored the toxicity mechanism of T-2 toxin on the hepatopancreas of E.sinensis at the mRNA level, which lays the foundation for further investigation of the molecular toxicity mechanism of T-2 toxin in aquatic crustaceans.
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Brachyura , Toxine T-2 , Animaux , Transcriptome , Toxine T-2/toxicité , Antioxydants/métabolisme , Hépatopancréas/métabolisme , Apoptose , Brachyura/génétiqueRÉSUMÉ
Recently, there has been an increasing number of blight disease reports associated with Erwinia amylovora and Erwinia pyrifoliae in South Korea. Current management protocols that have been conducted with antibiotics have faced resistance problems and the outbreak has not decreased. Because of this concern, the present study aimed to provide an alternative method to control the invasive fire blight outbreak in the nation using bacteriophages (phages) in combination with an antibiotic agent (kasugamycin). Among 54 phage isolates, we selected five phages, pEa_SNUABM_27, 31, 32, 47, and 48, based on their bacteriolytic efficacy. Although only phage pEa_SNUABM_27 showed host specificity for E. amylovora, all five phages presented complementary lytic potential that improved the host infectivity coverage of each phage All the phages in the cocktail solution could lyse phage-resistant strains. These strains had a decreased tolerance to the antibiotic kasugamycin, and a synergistic effect of phages and antibiotics was demonstrated both in vitro and on immature wound-infected apples. It is noteworthy that the antibacterial effect of the phage cocktail or phage cocktail-sub-minimal inhibitory concentration (MIC) of kasugamycin was significantly higher than the kasugamycin at the MIC. The selected phages were experimentally stable under environmental factors such as thermal or pH stress. Genomic analysis revealed these are novel Erwinia-infecting phages, and did not encode antibiotic-, virulence-, or lysogenic phage-related genes. In conclusion, we suggest the potential of the phage cocktail and kasugamycin combination as an effective strategy that would minimize the use of antibiotics, which are being excessively used in order to control fire blight pathogens.
RÉSUMÉ
With the growing demand for caviar products, sturgeon (family Acipenseridae) have become some of the most popular species in the aquaculture industry. Since sturgeon need more than 10 years to become sexually mature, protection against fatal diseases becomes particularly important in the industry. In March 2018, approximately 10% of Siberian Sturgeon Acipenser baerii fingerlings in a sturgeon hatchery in Jeolla Province, Republic of Korea, exhibited anorexia, abdominal distension, buoyancy loss, and abnormal behavior and eventually showed a 90% fatality rate. Twenty moribund fish were necropsied, and a distended stomach filled with gas was found in every case. A single colony dominated the intestinal lumen smear and was identified as Candida manassasensis by polymerase chain reaction targeting 18S ribosomal RNA. The same microorganism was also detected in the sturgeons' feed. Antifungal resistance was examined using the VITEK 2 system, and the isolate was susceptible to voriconazole, caspofungin, micafungin, and flucytosine. The environmental stress factor for this case was speculated as decreased water temperature. Since similar cases have been observed for many years, further research to optimize precise treatment and prevention methods is required.
Sujet(s)
Candidose , Maladies des poissons , Poissons , Animaux , Aquaculture , Candida , Poissons/génétique , IntestinsRÉSUMÉ
With concern growing over antibiotics resistance, the use of bacteriophages to combat resistant bacteria has been suggested as an alternative strategy with which to enable the selective control of targeted pathogens. One major challenge that restrains the therapeutic application of bacteriophages as antibacterial agents is their short lifespan, which limits their antibacterial effect in vivo. Here, we developed a polylactic-co-glycolic acid (PLGA)/alginate-composite microsphere for increasing the lifespan of bacteriophages in vivo. The alginate matrix in PLGA microspheres encapsulated the bacteriophages and protected them against destabilization by an organic solvent. Encapsulated bacteriophages were detected in the tissue for 28 days post-administration, while the bacteriophages administered without advanced encapsulation survived in vivo for only 3-5 days. The bacteriophages with extended fate showed prophylaxis against the bacterial pathogens for 28 days post-administration. This enhanced prophylaxis is presumed to have originated from the diminished immune response against these encapsulated bacteriophages because of their controlled release. Collectively, composite encapsulation has prophylactic potential against bacterial pathogens that threaten food safety and public health.
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Natural products have gained considerable attention for improving fish growth performance and immunity to enhance disease resistance. This study evaluated the effect of dandelion polysaccharides (DP) on skin mucosal immune parameters, immune-related gene expression, and susceptibility to pathogen challenge in the Common carp Cyprinus carpio. Diets containing four different concentrations of DP (g Kg-1):0 g [basal diet], 0.5 g [D1], 1.5 g [D2], 2.5 g [D3], and 4.0 g [D4] were fed to the carp (average weight: 13.92 ± 0.83 g) for eight weeks. Growth parameters were analyzed four and eight weeks after feeding. Immunological, hematological, and antioxidant parameters were examined eight weeks post-feeding. Growth performance was significantly higher on D3, with a final weight gain of 71.48 ± 1.57 g and a specific growth rate of 3.06 ± 0.12. Among hematological parameters examined, erythrocyte, hematocrit, and mean corpuscular volume (MCV) levels were significantly higher in D3. Skin mucosal immune parameters, such as lysozyme (31.04 ± 1.02 Unit mL-1), alkaline phosphatase (122.6 ± 3.8 IU L-1), and protein level (10.6 ± 0.74 mg mL-1) were significantly higher in D3, while peroxidase activity was higher in D4. Furthermore, SOD activity was higher in D2-D3, whereas catalase activity was higher in D2-D4 (P < 0.05) than in the control. Malondialdehyde level decreased significantly in D3 (5.43 ± 0.36 nmol mL-1); whereas, serum ALT and AST levels were significantly lower on D2-D4. Intestinal tight-junction-related genes ZO-1 and Claudin 7 were significantly higher in the DP-fed groups; however, DP had no significant effect on claudin 3. Occludin expression was higher (p < 0.05) on D3 only. Pro-inflammatory cytokines (IL-1ß and TNF-α) and IFN-γ strongly upregulated in the head kidney at D3. Conversely, the expression of the anti-inflammatory cytokine interleukin-10, HSP70, and TOR were considerably downregulated in D3. Fish from D3 exhibited markedly higher relative post-challenge survival (66.67%) against Aeromonas hydrophila challenge. The results of the present study suggest that dietary supplements of DP at 2.5 g kg-1 can significantly improve the growth performance, skin mucosal, and serum antioxidant parameters, and strengthen the immunity of C. carpio. Therefore, DP is a promising food additive for carp aquaculture.
Sujet(s)
Produits biologiques , Carpes (poisson) , Maladies des poissons , Infections bactériennes à Gram négatif , Taraxacum , Phosphatase alcaline , Aliment pour animaux/analyse , Animaux , Antioxydants/métabolisme , Carpes (poisson)/métabolisme , Catalase , Claudine-3 , Cytokines/génétique , Régime alimentaire/médecine vétérinaire , Compléments alimentaires , Additifs alimentaires , Interleukine-10 , Malonaldéhyde , Lysozyme , Occludine , Polyosides/pharmacologie , Superoxide dismutase , Facteur de nécrose tumorale alphaRÉSUMÉ
Global warming is favouring the incidence, intensity and duration of harmful cyanobacterial blooms. Microcystin-LR (MC-LR), a hepatotoxic agent, is produced during cyanobacterial blooms. To understand the molecular mechanisms of acute hepatotoxic effect of low doses of MC-LR in crab, we examined differentially expressed genes in samples of the hepatopancreas of Chinese mitten crab (Eriocheir sinensis) collected in 48 h after injections of MC-LR at doses of 0, 25, 50, and 75 µg/kg. The results revealed that MC-LR induced changes in corresponding gene led to the accumulation of triglycerides. MC-LR exposure affected sterol metabolism. Apoptosis-related genes such as Fas-L, Bcl-XL, Cytc, AiF, p53, PERK, calpain, CASP2, CASP7, α-tubulin, PARP, GF, G12, and PKC were upregulated. Conversely, expression levels of CASP10 and ASK1 were downregulated. Genes related to the regulation of actin cytoskeleton (Rho, ROCK, MLCP, MLC, PAK, and PFN) were upregulated. Further, expression levels of genes encoding fatty acid elongation-related enzymes were upregulated, but the expression of genes related to fatty acid synthesis was slightly down regulated. Taken together, these results demonstrated the hepatic toxicity and molecular mechanisms of changes in lipid metabolism, immune and apoptosis in Chinese mitten crab under the MC-LR-induced stress, which is the first report on crabs and performs a comprehensive analysis and a new insight of the molecular toxicological responses in crabs.
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Hépatopancréas , Transcriptome , Animaux , Apoptose , Chine , Acides gras/pharmacologie , Métabolisme lipidique , Toxines de la flore et de la faune marines , Microcystines/toxicitéRÉSUMÉ
In the aquaculture industry, an efficient and safe water purification system is important to prevent mass mortality by virulent pathogens. As extensive use of traditional methods (e.g.: povidone-iodine, ozone, ultraviolet irradiation, formalin, and chlorine dioxide) have adverse effects on cultured fish, an appropriate and alternative water purification method is vital for the sustainability of the industry. Non-thermal plasma technology has been successfully used for various biomedical purposes (e.g: food sterilization, medical device disinfection, wound healing, cancer therapy, etc.) and has great potential to be used as a sterilizing system. However, few studies have been conducted on its usefulness in the aquaculture industry. In this study, we investigated the bactericidal efficacy of plasma-activated water induced by non-thermal plasma and its histopathological as well as immunological adverse effects on koi. A highly virulent Aeromonas hydrophila SNU HS7, which caused massive mortality of koi, was used for this study. Non-thermal plasma was applied for 10 min to the fish tanks with 1.2 × 109 CFU/mL SNU HS7 using PLMB-20 system to confirm the sterilization efficacy and to observe the survival and immunological reaction of koi for 14 days. As a result, gross pathological, histopathological, and immunological investigations did not reveal any significant adverse effects in fish as compared to the control groups. To the best of our knowledge, this is the first study showing that non-thermal plasma can be used for sterilization of rearing water without giving significant physiological damage to the fish, even under the assumption of extreme situations. As plasma can effectively sterilize not only bacteria but also other unknown pathogens, the results of this study are showing a promising future in purifying water in aquaculture practice.
Sujet(s)
Carpes (poisson) , Maladies des poissons , Infections bactériennes à Gram négatif , Aeromonas hydrophila , Animaux , Antibactériens , Aquaculture , Carpes (poisson)/immunologie , Carpes (poisson)/microbiologie , Maladies des poissons/immunologie , Maladies des poissons/microbiologie , Infections bactériennes à Gram négatif/immunologie , Infections bactériennes à Gram négatif/médecine vétérinaire , Gaz plasmas , EauRÉSUMÉ
Salmonellosis is a disease of critical concern for public health, and the use of bacteriophages is among the most promising approaches to combating Salmonella. As Salmonella has various serotypes and strains, and bacteriophages are virulent to specific hosts, it is important to isolate phages and evaluate interactions with their hosts. In the present study, a novel Salmonella-infecting bacteriophage, pSal-SNUABM-01, was isolated and characterized. Transmission electron microscopy revealed that the bacteriophage is a member of the family Podoviridae and possesses an elongated head and a short tail. The phage genome is circular and 89,500 bp in size. A total of 162 open reading frames were predicted, eight of which were tRNAs. Morphological and genomic analysis revealed that pSal-SNUABM-01 is closely related to phage 7-11. In phylogenetic analysis, pSal-SNUABM-01 and 7-11 did not cluster together with the members of any established genus, suggesting that these two phages comprise a novel genus. The results of this study enhance our understanding of the phylogeny of the family Podoviridae and might be applicable to the development of bacteriophage treatments against Salmonella infections.