Sensitivity of Litopenaeus vannamei to Fusarium mycotoxins: the toxicity of low dose of Fumonisins and Deoxynivalenol and its accumulation in closed systems

The awareness of mycotoxin-related issues in aquaculture has grown as feed manufacturers and producers realize the importance of mycotoxins and their potential to impact production. Recent reports show that plant meals sourced in Asia, e.g., soybean meal, wheat, wheat bran, corn gluten meal, and rice bran, were mostly contaminated with Fusarium mycotoxins (zearalenone, deoxynivalenol and fumonisins)(Gonçalves et al., 2016). This contamination is later reflected in the finished feeds for shrimp and fish on values that can be higher than 2 ppm (Gonçalves et al., 2017).  A 36-day feeding trial was conducted to determine the effects of low contamination levels of Fumonisins (FB) and Deoxynivalenol (DON), alone and combined, on growth performance and selected health indices of white leg shrimp. Seven treatments were stablished in triplicate. Treatments: Control (no mycotoxins); 0.6FB (0.6 ppm of FB); 0.5DON (0.5 ppm of DON); 0.6FB+0.5DON (0.6 ppm of FB combined with 0.5 ppm of DON); 1FB (1 ppm of FB) and 1DON (1 ppm of DON), were established in the same recirculating system. The treatment CTRL RAS (independent RAS; no mycotoxins) was designed to have all the same physical and chemical rearing conditions as previous treatments, however reared on an independent RAS. Mycotoxin levels in feed were confirmed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) before starting the experiment and water of RAS system was analyzed for DON and FB at the end of the trial. Low levels of FB (0.6 ppm) and DON (0.5 ppm), alone or combined showed a clear negative impact on growth performance of Vannamei. FCR was the most impacted parameter. Within the 6 treatments sharing the same RAS, the combination of DON and FB, significantly increased the FCR by 88% compared to control. Results confirm that Litopenaeus vannamei is sensitive to DON and FB on levels normally found on shrimp feeds (Fegan and Spring, 2007; Gonçalves et al., 2016; Gonçalves et al., 2017). The presence of FB in water brings an extra concern, especially for closed production systems.

Keywords: Deoxynivalenol, Fumonisins, Pacific white leg shrimp, RAS