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This article discusses the expression profiles of heat shock protein 70 (Hsp70) and high-mobility groups box-1 protein (Hmgb1) in gnotobiotic brine shrimp challenged with different virulence levels of isogenic Vibrio harveyi strains. Vibrio harveyi is a marine bacterium that causes vibriosis in marine animals and has been found to regulate its pathogenicity through the production of virulence factors. The study aimed to determine whether different levels of virulence in V. harveyi strains affect the mRNA translational machinery of the host defense system in brine shrimp. The results showed that exposure to V. harveyi may modulate the synthesis of Hsp70 and Hmgb1 proteins in brine shrimp, suggesting a potential effect on the host's defense system. Further research is needed to understand the impact of pathogenic factors on the translational machinery of the host defense system. The study was supported by various funding sources and the authors declare no conflicts of interest. [Extracted from the article]

White spot syndrome virus (WSSV) is marked as one of the most economically devastating pathogens in shrimp aquaculture worldwide. Infection of cultured shrimp can lead to mass mortality (up to 100%). Although progress has been made, our understanding of WSSV's infection process and the virus–host–environment interaction is far from complete. This in turn hinders the development of effective mitigation strategies against WSSV. Infection models occupy a crucial first step in the research flow that tries to elucidate the infectious disease process to develop new antiviral treatments. Moreover, since the establishment of continuous shrimp cell lines is a work in progress, the development and use of standardized in vivo infection models that reflect the host–pathogen interaction in shrimp is a necessity. This review critically examines key aspects of in vivo WSSV infection model development that are often overlooked, such as standardization, (post)larval quality, inoculum type and choice of inoculation procedure, housing conditions, and shrimp welfare considerations. Furthermore, the usefulness of experimental infection models for different lines of WSSV research will be discussed with the aim to aid researchers when choosing a suitable model for their research needs. [ABSTRACT FROM AUTHOR]

Acute Hepatopancreatic Necrosis Disease (AHPND), a highly destructive shrimp disease, has inflicted severe setbacks on the shrimp farming industry worldwide. As the use of antibiotics is discouraged due to emerging antibiotic-resistant bacteria and the pollution of ecosystems, there is a pressing demand for novel, sustainable alternatives. Hence, the influence of bovine lactoferrin (bLF) and hen ovotransferrin (OT), two natural antimicrobial proteins, on the growth of three AHPND-causing Vibrio parahaemolyticus (Vp) strains (M0904, TW01 and PV1) was examined. Additionally, we explored their potential to affect selected Vp virulence factors such as biofilm formation, swimming and swarming, cell surface hydrophobicity, and activity of released lipases and caseinases. Lag phases of all bacterial growth curves were significantly prolonged in the presence of bLF or OT (1, 5 and 10 mg/mL), and bLF (5 and 10 mg/mL) completely inhibited growth of all strains. In addition, bLF or OT significantly reduced biofilm formation (all tested bLF and OT concentrations for Vp M0904 and Vp PV1), bacterial swimming motility (0.5 mg/mL bLF and OT for Vp M0904 and Vp TW01; 1 mg/mL bLF and OT for all strains), cell surface hydrophobicity (for all strains, all bLF and OT concentrations tested except for 0.125 mg/mL OT for Vp PV1) and lipase activity (1 mg/mL bLF and OT for all strains and 0.5 mg/mL bLF and OT for Vp PV1). These promising in vitro results suggest that bLF and/or OT might be used as novel agents for combating AHPND and warrant further research to elucidate the underlying mechanisms of action to fully unlock their potential for AHPND disease management. [ABSTRACT FROM AUTHOR]

β-Glucans are a group of heterogeneous glucose polymers that possess immunomodulatory activities. The complex nature of their structures, uncertainty regarding the doses, and variable immune effects pose a challenge to comprehensive understanding. In this study, we investigated the immune responses and apoptosis effects in Nile tilapia (Oreochromis niloticus) head kidney macrophages (MФ) upon exposure to two b-Glucans (Paramylon and Laminarin) at low and high doses. Our results demonstrate that Paramylon elicits more robust immune responses than Laminarin, albeit with a dose-limiting effect. We also observed that the high-dose Paramylon induces apoptosis, whereas no such effect was detected in Laminarin treatment. Mechanistically, high-dose Paramylon activates the intrinsic apoptosis pathway, with significantly up-regulation of intrinsic apoptosis-related genes and impaired mitochondrial function. On the other hand, Laminarin triggers metabolic reprogramming in MФ, resulting in the enrichment of the metabolite a-Ketoglutarate, which protects the MФ from apoptosis. Overall, our findings highlight the importance of identifying the optimal dose range for b-Glucans, based on sources or structures, to achieve maximal immunomodulatory effects. These results have important implications for the design and optimization of b-Glucans-based drugs or adjuvants in immunotherapies. [ABSTRACT FROM AUTHOR]

This present paper aimed to review the past 4 years (2019–2022), the inhibition of Vibrio spp. (including Vibrio's causing AHPND) by EOs, as well as the potential toxicity of the EOs towards crustaceans, with an emphasis on Artemia spp. In the present review, 27 EOs from terrestrial plants are reported regarding their anti‐Vibrio activity. Among these 27 studies, Salvia officinalis and Thymus vulgaris (Lamiaceae family) were found to be the most numerous. Among the Vibrio spp., V. parahaemolyticus (non‐AHPND strain) was mostly researched. There are in total 68 publications about the toxicity of EOs in Artemia spp. Based on the four categories of toxicity towards Artemia (strongly toxic: LC50 < 100 μg/ml, moderately toxic: LC50:100–500 μg/ml, weakly toxic: LC50: 500–1000 μg/ml, and non‐toxic: LC50 > 1000 μg/ml), strong toxicity activity was found in 37 EOs, moderate toxicity in 15 EOs, weak activity for three EO plants and 13 non‐toxic extracts. In fact, LC50 values as low as 10.25 and 11.48 μg/ml were described in Artemisia vulgaris and Euryale ferox, respectively, showing these two plant EOs are strongly toxic to Artemia. Overall, and despite being generally considered "eco‐friendly and natural" products and safer than antibiotics, some of the EOs are toxic to target organisms. Thus, to establish an ecologically safe application of EOs in shrimp aquaculture, the correct use of these plant EOs (in terms of concentrations and duration) in aquaculture should be considered. [ABSTRACT FROM AUTHOR]

White spot disease (WSD) is a severe viral threat to the global shrimp aquaculture industry. However, little is known about white spot syndrome virus (WSSV) transmission dynamics. Our aim was to elucidate this in Litopenaeus vannamei using peroral in vivo WSSV challenge experiments. We demonstrated that WSD progression was rapid and irreversible, leading to death within 78 h. Viral DNA shedding was detected within 6 h of disease onset. This shedding intensified over time, reaching a peak within 12 h of the time of death. Isolating shrimp (clinically healthy and diseased) from infected populations at different time points post-inoculation showed that host-to-host WSSV transmission was occurring around the time of death. Exposing sentinels to environmental components (i.e., water, feces, molts) collected from tanks housing WSSV-infected shrimp resulted in a significantly (p-value < 0.05) increased infection risk after exposure to water (1.0) compared to the risk of infection after exposure to feces (0.2) or molts (0.0). Furthermore, ingestion of WSSV-infected tissues (cannibalism) did not cause a significantly higher number of WSD cases compared to immersion in water in which the same degree of cannibalism had taken place. [ABSTRACT FROM AUTHOR]