Effect of the mycotoxin deoxynivalenol on the immune responses of rainbow trout (Oncorhynchus mykiss)

Abstract

ABSTRACT:The trichothecene mycotoxin deoxynivalenol (DON) is commonly found as a natural contaminant in cereals such as wheat, barley, and corn, and exhibits various toxicological effects when present in animal feeds. The effects of DON at a nominal 2 mg/kg feed on immune responses of rainbow trout were investigated, including relative gene expression of important cytokines (TNF-α, IL-8, IL-1β, IL-10), lysozyme concentration in skin mucus, and level of antigen-specific IgM in blood plasma after vaccination with the commercial vaccine AquaVac ERM containing Yersinia ruckeri type 1 (Hagerman strain). Twenty one-year-old rainbow trout Oncorhynchus mykiss were randomly divided into two groups. The control received a commercial feed with a naturally occurring low level of DON (225 μg/kg feed), while an experimental group was fed the same formulation with DON added to 1964 μg/kg feed. The trial continued for 23 days. Consumption of feed with added DON showed a significant effect on the immune system, as indicated by a higher level of pro-inflammatory cytokine TNF-α (P < 0.05) and of IL-8 (non-significant) in head kidney. Expression of the pro-inflammatory gene IL-1β and the expression of a gene encoding anti-inflammatory cytokine (IL-10) were not influenced by DON treatment. Effects on the concentration of skin mucus lysozyme and specific IgM antibody levels were not observed during this experiment. These results suggest that prolonged ingestion of low doses of DON may influence the immune responses of rainbow trout.

Effects of deoxynivalenol exposure time and contamination levels on rainbow trout

“…Contamination levels were chosen taking into account previous literature on the effect of DON on rainbow trout (Hooft et al, ; Matejova et al, ; Matejova et al, ; Ryerse et al, ) as well as the reported DON levels in worldwide finished feed samples (Barbosa et al, ; Gonçalves, Hofstetter, et al, ; Gonçalves, Navarro‐Guillén, et al, ; Gonçalves et al, ; Gonçalves, Schatzmayr, Hoffstetter, & Santos, ; Greco, Pardo, & Pose, ). The long‐term exposure to DON attempts to mimic the most recently reported levels of DON in finished feeds (Gonçalves, Hofstetter, et al, ; average of 82.87 μg/kg and maximum of 396 μg/kg).…”

“…Trichothecenes are extremely potent inhibitors of eukaryotic protein synthesis, interfering with the initiation, elongation, and termination stages of this process (Kumar, Roy, Barman, & Anand, ). Knowledge of the effects of DON on aquatic species has increased recently (Gonçalves, Hofstetter, et al, ; Hooft & Bureau, ; Hooft et al, ; Matejova et al, ; Ryerse et al, ; Tola et al, ), and studies on rainbow trout suggest that DON has a detrimental effect on feed intake (FI), weight gain, and feed efficiency (Hooft et al, ; Ryerse et al, ). Curiously, no effect has been detected on the immune status of animals fed with DON (Matejova et al, ; Matejova, Svobodova, Vakula, Mares, & Modra, ; Ryerse et al, ).…”

The Occurrence of Mycotoxins in Raw Materials and Fish Feeds in Europe and the Potential Effects of Deoxynivalenol (DON) on the Health and Growth of Farmed Fish Species—A Review

“…Finally, some other studies addressed the effects of DON on health, immune function and oxidative stress [120][121][122]. When 1-yearold trout were exposed for 23 days to~2000 µg/kg DON, plasma biochemical parameters; glucose, cholesterol and ammonia were decreased [120], pro-inflammatory cytokine TNF-α in the head kidney was up-regulated [121] and altered activities of antioxidant enzymes were observed [122]. Overall, the sensitivity of rainbow trout productivity to DON is well defined, although further research is needed to explore the direct mechanism of action of the toxin in this species.…”

Influence of mycotoxins on fish health

“…Uważa się, że znaczącą rolę we wpływie mikotoksyn na immunomodulację może mieć ich zdolność do pobudzania wydzielania cytokin pro-i przeciwzapalnych (24,29). Zostało wykazane, że zwiększona ekspresja genów odpowiedzialnych za wyrzut cytokin prowadzi w konsekwencji do uwolnienia supresorów hamujących odpowiedź zapalną i uszkodzenia tkanek (32).…”