White spot syndrome virus (WSSV) infection and immunity responses in white shrimp (Litopenaeus vannamei) exposed to sublethal levels of metals

Abstract

To determine if exposure to a sublethal mixture of metals (Cd, Cu, Fe, Mn, Pb and Zn) increases susceptibility to White spot syndrome virus (WSSV) infection, Litopenaeus vannamei juveniles were fed WSSV-infected shrimp tissues after 21 days of exposure to the metal mixture (WS-MM treatment). Other treatments consisted of shrimp not exposed to metals and fed infected tissues (WS), and shrimp fed healthy tissues and exposed (MM) or not exposed to metals (C). The presence of viral DNA and inclusion bodies was detected at 32 hr postinfection (hpi) in the stomach epithelium of shrimp from the WS treatment, and eight hours later in shrimp from the WS-MM treatment, possibly because of an initial negative effect of metals in viral replication. At 40 hpi, the severity of infection represented by the histopathological index increased in both WS and WS-MM treatments, and values were higher in WS-MM than in WS shrimp at the end of the experiment. From 56 hpi to the end of experiment, total hemocyte counts were lower in both WS-MM and WS treatments, and concentrations were particularly low in WS-MM shrimp. Conversely, phenoloxidase activity was higher in the WS-MM treatment from 32 to 56 hpi, suggesting a possible role of the prophenoloxidase (proPO) system in the antiviral defense against WSSV. The presence of heavy metals at sublethal concentrations may increase shrimp susceptibility to WSSV; this is supported by a decrease in circulating hemocytes, an increase in the humoral response, and the development of a higher number of WSSV inclusion bodies. K E Y W O R D S heavy metals, immune responses, Litopenaeus vannamei, proPO activity, WSSV

Evaluation of a new Argovit as an antiviral agent included in feed to protect the shrimpLitopenaeus vannameiagainst White Spot Syndrome Virus infection

“…The proPO gene encodes the phenoloxidase precursor enzyme, with L. vannamei encoding LvproPO1 and LvproPO2 (Wang et al, 2010). Interestingly, proPO has been shown to be active during WSSV infection (Abad-Rosales et al, 2019). In this study, proPO gene expression exhibited a significant decrease at 48 h compared with that observed in the control.…”

“…The genes encoding Crustin and PEN4 have been identified as participating in antiviral immunity against WSSV infections in L. vannamei (Sun, Wang & Zhu, 2017;Huan et al, 2011). Finally, the proPO gene activates the proPO system, which is involved in melanin formation in arthropods and other invertebrates (Sritunyalucksana & Soderhall, 2000) and results in the production of the melanin pigment that can often be seen as dark spots in the cuticle of arthropods and two antimicrobial peptides from defence system also in WSSV infections (Abad-Rosales et al, 2019). These advances have demonstrated that AgNPs are effective against a wide spectrum of viruses, especially against the disease-causing WSSV, for which there have been no effective treatments until now (Verbruggen et al, 2016).…”

Benzoic Acid Inclusion Effects on Health Status and Growth Performance of Juvenile Pacific White Shrimp Penaeus vannamei

“…The Sd values obtained from each evaluated tissue were recorded, and a global histopathological index (Hi) per shrimp was calculated according to the method used by Abad‐Rosales et al. (2018) via the following formula: Hi = Σ(Sd/4 × V ), with a global Hi range of 0–6.…”

Evaluation of the occurrence and fate of pesticides in a typical Mediterranean delta ecosystem (Ebro River Delta) and risk assessment for aquatic organisms

“…For instance, the exposure of carps to organophosphates and carbamate pesticides produced neurotoxicity (Wang et al, 2015), by inhibiting the activity of acetylcholinesterase (AChE) and interfering with the normal behavior of this species. The combined presence of organochlorine and organophosphate pesticides resulted in a synergistic effect that decreased the immune response capacity of white shrimps (Abad-Rosales et al, 2019;Bautista-Covarrubias et al, 2020). A recent study has also demonstrated that mixtures of pyrethroids and neonicotinoids exhibit a synergistic effect in the enzyme activity and gene expression of embryonic zebrafish (Wang et al, 2020).…”