Mycotoxins in Southeast Asian aquaculture: plant-based meals and finished feeds

The awareness of mycotoxin-related issues in aquaculture industry has grown as manufacturers and producers realise the importance of mycotoxins, beyond aflatoxin, and their potential to impact production. During a period of one year (January 2016-December 2016), 175 samples of different plant proteins, aquaculture/fishery by-products and finished aquaculture feeds, were analysed. Samples were tested for aflatoxins (aflatoxin B-1, B-2, G(1) and G(2)); zearalenone; type B trichothecenes (deoxynivalenol (DON); nivalenol; 3-acetyldeoxynivalenol; 15-acetyldeoxynivalenol and fusarenon X-glucoside); fumonisins (fumonisin B-1, B-2 and B-3); type A trichothecenes (T-2 and HT-2 toxin; diacetoxyscirpenol and neosolaniol); and ochratoxin A. All samples were sourced in Southeast Asia. Within the analysed samples, 4% were free of detectable mycotoxins. 8% of the samples had one mycotoxin and 88% of the samples were contaminated with more than one mycotoxin. The current work show similarity to previous studies, that mycotoxin occurrence in plant-meals, and consequently in finished feeds, is quite variable and confirms that aflatoxin is not the main mycotoxin in aquafeeds. Mycotoxin occurrence in fish and shrimp feeds in the present samples were higher than reported in previous studies for the same region. In samples of shrimp feed with DON detected, the mean average DON level was 882 mu g/kg with a maximum level of 2,287 mu g/kg. These values are within the reported sensitivity levels of white leg shrimp (Litopenaeus vannamei). Despite the limited number and short period of sampling, this inventory study helps address a knowledge gap of mycotoxin occurrence in feeds specifically destined for the aquaculture industry.