ORCID Profile
0000-0003-0812-4764
Current Organisation
Chiang Mai University
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Publisher: MDPI AG
Date: 09-11-2022
DOI: 10.20944/PREPRINTS202211.0163.V1
Abstract: Nervous necrosis virus (NNV) has spread throughout the world, affecting more than 120 freshwater and marine fish species. While vaccination effectively prevents disease outbreaks, the difficulty of producing sufficient viruses using cell lines continues to be a significant disadvantage for producing inactivated vaccines. This study, therefore, explored the application of synthetic peptides as potential vaccine candidates for the prevention of NNV in Asian seabass (Lates calcarifer). Using the epitope prediction tool and molecular docking, three predicted immunogenic B cell epitopes (30-32 aa) derived from NNV coat protein were selected and synthesised, corresponding to amino acid positions 5 to 34 (P1), 133 to 162 (P2) and 181 to 212 (P3). All the predicted peptides interact with Asian sea bass& rsquo s MHC class II by docking. The antigenicity of these peptides was determined through ELISA and all peptides were able to react with NNV-specific antibodies. Subsequently, the immunogenicity of these synthetic peptides was investigated by immunisation of Asian seabass with in idual peptides (30 & mu g/fish) and a peptide cocktail (P1+P2+P3, 10 & mu g each/fish) by intraperitoneal injection, followed by a booster dose at day 28 post-primary immunisation. There was a subset of immunised fish that were able to induce upregulation of CD4 in the head kidney and spleen. Importantly, antibodies derived from fish immunised with synthetic peptides reacted with whole NNV virions. Taken together, these findings indicate that synthetic linear peptides based on predicted B cell epitopes exhibited both antigenic and immunogenic properties, suggesting that they could be potential vaccine candidates for the prevention of NNV in fish.
Publisher: Wiley
Date: 10-06-2021
DOI: 10.1111/JFD.13451
Abstract: A rapid increase in multi‐drug‐resistant (MDR) bacteria in aquaculture highlights the risk of production losses due to diseases and potential public health concerns. Previously, we reported that ozone nanobubbles (NB‐O 3 ) were effective at reducing concentrations of pathogenic bacteria in water and modulating fish immunity against pathogens however, multiple treatments with direct NB‐O 3 exposures caused alterations to the gills of exposed fish. Here, we set up a modified recirculation system (MRS) assembled with an NB‐O 3 device (MRS‐NB‐O 3 ) to investigate whether MRS‐NB‐O 3 (a) were safe for tilapia ( Oreochromis niloticus ), (b) were effective at reducing bacterial load in rearing water and (c) improved survivability of Nile tilapia following an immersion challenge with a lethal dose of MDR Aeromonas hydrophila . The results showed no behavioural abnormalities or mortality of Nile tilapia during the 14‐day study using the MRS‐NB‐O 3 system. In the immersion challenge, although high bacterial concentration (~2 × 10 7 CFU/ml) was used, multiple NB‐O 3 treatments in the first two days reduced the bacteria between 15.9% and 35.6% of bacterial load in water, while bacterial concentration increased from 13.1% to 27.9% in the untreated control. There was slight up‐regulation of non‐specific immune‐related genes in the gills of the fish receiving NB‐O 3 treatments. Most importantly, this treatment significantly improved survivability of Nile tilapia with relative percentage survival (RPS) of 64.7% – 66.7% in treated fish and surviving fish developed specific antibody against MDR A. hydrophila . In summary, the result suggests that NB‐O 3 is a promising non‐antibiotic approach to control bacterial diseases, including MDR bacteria, and has high potential for application in recirculation aquaculture system (RAS).
Publisher: Cold Spring Harbor Laboratory
Date: 10-06-2023
DOI: 10.1101/2023.06.09.544435
Abstract: The treatment of Nile tilapia with ozone nanobubbles (ONb) prior to vaccination with an immersible heat-killed Streptococcus agalactiae ( Sa ) vaccine has been reported to modulate and enhance both innate and specific immunity. The efficacy of this novel vaccination strategy is explored further in field trials. This strategy involved a short-term treatment of ONb to activate the fish’s immunity prior to immersion vaccination during their transportation in oxygenated plastic bags (VAC in BAG), followed by two oral boosters during the grow-out stage mixing vaccine in feed (VAC in FEED). The field trial was conducted over 112 days in open cages, comprising four groups: normal aeration control (AC), normal aeration + vaccine (AV), ONb control (NC), and ONb + vaccine (NV). The efficacy of the vaccine was evaluated by measuring specific antibodies for S. agalactiae , monitoring expressions of IgM and IgT transcripts in the gills and head kidney every two weeks, and a laboratory pathogen challenge. Results found that fish in the NV group had significant increases in anti- S. agalactiae antibodies after the primary dose, whereas fish in the AV group required an oral booster dose to produce significant anti- S. agalactiae antibodies. In the vaccinated groups (AV and NV), only IgM was observed to be upregulated at 14 days post-immersion (dpi), while this gene was upregulated in both gills and head kidney in the NC group. No statistically significant upregulation of IgT was recorded in any group at any time point. Despite a decline in the levels of specific antibodies among the vaccinated groups at the time of challenge (88 dpi), the NV and AV groups demonstrated a relative percent survival (RPS) of 50% and 46.7%, respectively, following a relatively high injection dose of S. agalactiae injection (0.1 mL of 10 8 CFU/mL). In summary, this ONb, VAC in BAG and VAC in FEED vaccination strategy represents a promising alternative to the undesirable handling and costly injection approach used within the Nile tilapia industry.
Publisher: Wiley
Date: 30-05-2022
DOI: 10.1111/JFD.13663
Abstract: Tilapia parvovirus (TiPV) is an emerging virus reportedly associated with disease and mortality in farmed tilapia. Although previous descriptions of histopathological changes are available, the lesions reported in these are not pathognomonic. Here, we report Cowdry type A inclusion bodies (CAIB) in the pancreas as a diagnostic histopathological feature found in adult Nile tilapia naturally infected with TiPV. This type of inclusion body has been well‐known as a histopathological landmark for the diagnosis of other parvoviral infections in shrimp and terrestrial species. Interestingly, this lesion could be exclusively observed in pancreatic acinar cells, both in the hepatopancreas and pancreatic tissue along the intestine. In situ hybridization (ISH) using a TiPV‐specific probe revealed the intranuclear presence of TiPV DNA in multiple tissues, including the liver, pancreas, kidney, spleen, gills and the membrane of oocytes in the ovary. These findings suggest that although TiPV can replicate in several tissue types, CAIB manifest exclusively in pancreatic tissues. In addition to TiPV, most diseased fish were co‐infected with Streptococcus agalactiae , and presented with multifocal granulomas secondary to this bacterial infection. Partial genome lification of TiPV was successful and revealed high nucleotide identity ( %) to previously reported isolates. In summary, this study highlights the usefulness of pancreatic tissue as a prime target for histopathological diagnosis of TiPV in diseased Nile tilapia. This pattern may be critical when determining the presence of TiPV infection in new geographic areas, where ancillary testing may not be available. TiPV pathogenesis in this landmark organ warrants further investigation.
Publisher: Elsevier BV
Date: 12-2023
Publisher: Cold Spring Harbor Laboratory
Date: 13-12-2021
DOI: 10.1101/2021.12.13.472363
Abstract: Nanobubble technology has shown appealing technical benefits and potential applications in aquaculture. We recently found that treatment with ozone nanobubbles (NB-O 3 ) activated expression of several immune-related genes leading to effective response to subsequent exposure to fish pathogens. In this study, we investigated whether pre-treatment of Nile tilapia ( Oreochromis niloticus ) with NB-O 3 can enhance specific immune responses and improve efficacy of immersion vaccination against Streptococcus agalactiae . Spleen and head kidney of fish in the vaccinated groups showed a substantial upregulation in expression levels of three immunoglobulin classes( IgM , IgD , and IgT ) compared with the unvaccinated control groups. At day 21 post-immunization, the relative expression was greatest (approx. 3.2 to 4.1 folds). Both systemic and mucosal IgM antibodies were elicited in vaccinated groups. As the result, the cumulative survival rate of the vaccinated groups was found to be higher than that of the unvaccinated groups, with a relative percent survival (RPS) ranging from 52.9-70.5%. However, fish in the vaccinated groups that received pre-treatment with NB-O 3 , bacterial antigen uptakes, expression levels of IgM , IgD , and IgT , as well as the specific-IgM antibody levels and percent survival, were all slightly or significantly higher than that of the vaccinated group without pre-treatment with NB-O 3 . Taken together, our findings suggest that utilizing pre-treatment with NB-O 3 may improve the immune response and efficacy of immersion vaccination in Nile tilapia. Immune response and efficacy of a heat-killed Streptococcus agalactiae immersion vaccine for Nile tilapia with and without pre-treatment with NB-O 3 were accessed. Bacterial antigen uptake in the NB-O 3 -VAC compared to the AT-VAC groups was increased 1.32 and 1.80-fold at 3 and 6 h post-vaccination, respectively. Vaccinated group that received pre-treatment with NB-O 3 had slightly to significantly higher levels of IgM , IgD , and IgT mRNA expression IgM levels and survival rate. Pre-treatment with NB-O 3 may be a novel strategy for improving efficacy of immersion vaccine in aquaculture
No related grants have been discovered for Linh Nguyen Vu.