Analysis of the white sturgeon (Acipenser transmontanus) immune response during immunostimulation and Veronaea botryosa infection

https://doi.org/10.1016/j.cbd.2021.100879Get rights and content
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Highlights

  • Feed supplementation with b-glucans could be used to help prevent losses due to V. botryosa in cultured white sturgeon.

  • A strong proinflammatory response was detected in V. botryosa exposed white sturgeon regardless of glucan supplementation.

  • Protection conferred by b-glucans is at least partially associated with a higher expression of IL17 and IRF8.

Abstract

Systemic phaeohyphomycosis caused by Veronaea botryosa is regarded as an important emerging mycotic disease of sturgeon aquaculture. However, no vaccines or treatments are currently available. The effects of dietary β-glucan supplementation on resistance to V. botryosa infection was examined in controlled challenges by exposing immunostimulated and control fish to ~7.25 × 105 fungal spores/fish via intra-muscular injection. Six weeks post-challenge, cumulative mortality was determined and antibodies to acute phase-proteins (APP) were used to quantify the conserved APP peptides in the serum of challenged and control fish using Western blot. Transcript levels for all tested pro-inflammatory cytokines, APP, and regulatory cytokines in the spleen were similar amongst treatments at the end of the three-week feeding period. However, significantly higher survival occurred in fingerlings fed 0.3% β-glucans compared to non-immunostimulated fish groups (p < 0.05) six weeks post-challenge. A strong proinflammatory response was detected in exposed treatment groups, and greater survival at 6 weeks was associated with higher transcript abundance of Il-17 in fish fed β-glucans. Findings support the important role of this cytokine in response to fungal infection.

Keywords

Aquaculture
Caviar
Fungus
IL-17
Immunostimulation

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