ISSUE FOCUS FEED & ADDITIVE MAGAZINE May 2025 49 • Over 90% of DDGS samples contained Fusarium-produced mycotoxins such as fumonisins, and around 13% of these samples also contained aflatoxin B1. • Soybean meal samples were found to contain fusaric acid, while wheat and corn samples showed high levels of type B trichothecenes (e.g., deoxynivalenol). • Notably, emerging mycotoxins — toxins that are not yet regulated — were found in over 70% of all samples tested, highlighting the rising risk and the necessity of proper mycotoxin management. EFFECTS OF MYCOTOXINS ON AQUATIC SPECIES The presence of mycotoxins in aquafeeds poses significant risks to aquatic species. Mycotoxins can impair growth, immune response, and overall health in fish and shrimp. Each aqua species exhibits specific sensitivities to different mycotoxins. For instance, carp are particularly vulnerable to deoxynivalenol, which has been shown to affect organ health and reduce growth performance. T-2 toxin, another common mycotoxin, can decrease feed intake and cause oxidative stress and DNA damage in common carp. In shrimp, even low concentrations of deoxynivalenol (around 330 ppb) can lead to reduced weight gain and can impact gene expression related to antioxidative defenses. T-2 toxin and fumonisins also significantly affect shrimp health, leading to muscle deterioration, reduced growth and increased mortality. These changes not only affect the animals’ welfare but also reduce the quality and nutritional value of shrimp for consumers. Geographical regions also vary in their susceptibility to the different mycotoxin types. For instance, storage mycotoxins such as aflatoxin and ochratoxin A are of particular concern in the Asia-Pacific region due to the high temperatures and humidity that favor their growth. These mycotoxins can reduce feed efficiency, damage vital organs like the hepatopancreas, and lower survival rates in aquatic species. MYCOTOXIN PREVENTION AND MITIGATION STRATEGIES Mycotoxin contamination can occur before and/ or after harvest — but preventing fungal growth on crops pre-harvest has become increasingly challenging due to climate change. As a result, feed mills are now more likely to receive feedstuffs that have already been contaminated in the fields. Fortunately, some preventive and corrective steps can be implemented at this stage to mitigate the risk of exposing fish and shrimp to mycotoxins. In fact, mycotoxin prevention and mitigation strategies along the aquafeed supply chain are primarily implemented at the feed mill level (Figure 1). The implementation of a monitoring plan at feed mills, which screen feedstuffs upon arrival, is an effective option for preventing mycotoxin contamination. Field Storage and manufacture Feed Mill • Mold-zap: Mold inhibitor in the feed • Mycosorb: Mycotoxin-binding agent in the feed • Quality control: Testing grains for mycotoxins Farm Figure 1. Recommended mycotoxin prevention and mitigation strategies for feed mills
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