Dr Roy Rosen presents mycotoxins in aquaculture at Aqua Partner Days 2026, dsm-firmenich Tulln facility, Austria; Co-contamination common across feeds.
Mycotoxins in aquaculture: managing feed risk
Published on 14 August 2026
This article is based on a presentation by Dr. Roy during the Aqua Partner Days 2026 at dsm-firmenich’s Tulln facility in Austria. As aquaculture continues its global expansion, the industry is facing increasing pressure from volatile raw material markets, sustainability demands and changing feed formulations. According to Dr Roy Rosen, scientist at dsm-firmenich, Animal Nutrition & Health and member of the Translational Science Mycotoxin Team, these changes are making mycotoxin risk management more important than ever for aquaculture producers. Speaking during a recent presentation on mycotoxins in aquaculture, Dr Rosen explained that the sector’s increasing reliance on plant-based ingredients and alternative raw materials is raising the likelihood of contamination in aquatic feeds. “The aquaculture industry is growing and is predicted and expected to continue to grow,” Dr Rosen said. “But feed costs still remain the single most important driver of profitability.” He noted that market prices, disease prevention and feed costs are among the industry’s main concerns, citing figures from the Rabobank Global Aquaculture Outlook 2026 and that all three can be influenced by effective mycotoxin management. Dr Rosen highlighted how geopolitical instability and climate-related disruptions are rapidly reshaping feed formulation strategies worldwide due to availability and costs. “If you put on top aspects of sustainability, fisheries and marine ingredients usage policies, this all leads to a situation that the formulation and the adaptation to these changes have to be very quick. And this comes with the price and with the risk.” According to Dr Rosen, the ongoing shift away from marine ingredients towards plant proteins, plant material concentrates and food, industry and agricultural side streams such as DDGS, is increasing the risk of mycotoxin introduction into the aqua feed formulation. Novel ingredients such as insects, microalgae and microbial biomass are also entering aquafeed formulations, creating new challenges for feed safety evaluation. “We see the long-term trend of marine protein replacement and plant protein introduction into the formulation, if we consider it together with the novel ingredients and with the fast economic-geopolitical adaptations that really highlight the importance of checking your formulations for mycotoxin risk,” he said. Dr Rosen explained that mycotoxins are toxic secondary metabolites produced by fungi and increase under stressful conditions, often triggered by extreme weather events, environmental stress or pest pressure in crops such as maize, wheat and soy. Importantly, contamination is not restricted to crop cultivation. “These fungi that are already on the crop or in the commodities environment can continue to develop and produce mycotoxins also during the storage or during the shipping and delivery of the grains or feeds,” he explained. “So the risk is really all the way till the end.” He stressed that mycotoxins are highly stable compounds that survive common feed processing methods. “There was a misconception, if I extrude in harsh enough conditions, I will get rid of all contaminants including the mycotoxins,” Dr Roy said. “Studies show that this is really not the case.” He also warned that co-contamination is found to be common across feed samples, with multiple toxins often occurring simultaneously; this situation is now considered the rule and not the exception and can lead to synergistic effects where the combined effect of the toxins becomes more harmful than individual compounds alone, as shown in Image 4. “If you want, it’s like one plus one equals three,” he said. Drawing on results from the first quarter of the 2026 dsm-firmenich World Mycotoxin Survey, Dr Rosen said contamination remains widespread across global feed markets. The survey analyses mycotoxin prevalence by region, species and toxin type, helping producers benchmark their risk exposure and adjust mitigation strategies accordingly. “We are trying to provide the industry with a clear and very updated picture of the risk of mycotoxins based on the region,” Dr Rosen explained. The survey also aims to improve awareness and help producers tailor mitigation strategies to local conditions. Dr Rosen emphasised that unlike acute toxication, the chronic effects of mycotoxins in fish and shrimp are often subtle and difficult to identify early. “In nearly all cases we see reduction in performance over time,” he said. “We see negative impact on robustness, and there could also be an effect on product quality.” While research in shrimp remains more limited than in fish, he noted that emerging studies suggest shrimp may actually be more sensitive to mycotoxins than previously believed. “There was a concept in the past that because they are invertebrates, they might be more resistant to mycotoxins,” Dr Rosen said. “Research shows us that in many cases it is actually the opposite way.” One section of the presentation focused on aflatoxins, among the earliest mycotoxin-related problems documented in livestock and termed the ‘Turkey X’ disease and later on in aquaculture during the 1960s. Dr Rosen cited reports of severe trout hatchery mortalities in the United States that were later linked to mould-contaminated cottonseed meal used in feed. He explained that aflatoxins comprise several related compounds, with aflatoxin B1 being the most widely recognised and the primary form addressed by food and feed safety regulations. These are the most carcinogenic naturally occurring compounds and the most toxic mycotoxin; in fish, it primarily targets the liver. Exposure has been associated with severe hepatic damage, while prolonged exposure may lead to liver tumour and reduced product quality, which often is facilitated by chronic liver insufficiency and cirrhosis that may contribute to jaundice and yellow discolouration of fish tissues, including the fillet. Discussing a long-term tilapia study, he highlighted visible signs including eye opacity, yellowing and abnormal swimming behaviour. “These situations are easy for the layman to understand; both the farmer and for the consumer can easily see and understand how product quality can directly be affected,” he said. “If it’s yellow, they will not buy it.” He added that unusual fish behaviour may provide an early warning sign of contamination. “When we see changed feeding behaviour, erratic swimming or other unusual and unexplained behaviour maybe there is something in the feed,” he said. Dr Rosen also discussed research involving deoxynivalenol (DON) contamination in rainbow trout and Atlantic salmon. One key finding was that even relatively low contamination levels over extended periods could significantly reduce growth performance and condition factors. “It’s important to continue the monitoring and continue the control over time,” he explained. “Not to just sample once in a while and expect it to be okay.” Using benchmark dose modelling, researchers found that DON concentrations far below existing regulatory limits could still impair performance and immune responses. “Levels that are much lower than this can already lead to changes in parameters that will later translate to reduction in profitability,” Dr Rosen said. Reproductive disruption from zearalenone The presentation also explored the effects of zearalenone (ZEN), an oestrogenic mycotoxin capable of disrupting endocrine systems in fish. In one long-term study following fish from hatching to sexual maturity, exposure to ZEN caused significant reproductive abnormalities, including mixed-sex gonadal tissue and ovarian deformities. “Zearalenone is structurally similar to the female hormone oestrogen, which is also present in young animals and males in very low levels,” Dr Rosen explained. “It is extremely problematic in these cases that oestrogen should really not be present.” Research on fumonisins in shrimp demonstrated further concerns for final product quality (Image 6). According to Dr Rosen, exposure altered muscle fibre composition, which could result in softer texture and reduced shelf life. “The final product is softer, the texture is changed, and also the shelf life of this product is different than what you can expect,” he said. Another internal trial conducted by teams at the dsm-firmenich R&D center in Tulln and involved DON and ZEN exposure showed reduced growth performance and increased susceptibility to Vibrio parahaemolyticus infection following ammonia stress challenges. Their team also observed promising results when using a mycotoxin mitigation product during the trial. “We could see that there was a clear negative effect of mycotoxins in the diet on the susceptibility of the shrimp to the stress and the pathogen,” Dr Rosen said. Multi-layered mitigation strategies Addressing mycotoxin mitigation strategies, Dr Rosen noted that effective risk management requires more than traditional binding technologies alone. He explained that evaluating a binder involves not only measuring its ability to adsorb toxins but also ensuring that bound compounds remain stable and are not released later in the digestive tract or the environment. According to Dr Rosen, the evaluation approach used for the binders included in Mycofix® aligns with methodologies adopted by the European Reference Laboratory. He emphasised, however, that not all mycotoxins can be effectively controlled through adsorption. Compounds such as DON, FUM and ZEN require alternative approaches, prompting the development of a multi-layered risk management strategy. This includes biotransformation technologies, such as enzymes and other biological components designed to detoxify mycotoxins that cannot be readily bound, alongside a bioprotection blend of plant- and algae-derived ingredients intended to support animal health. Dr Rosen explained that the strategy is designed not only to reduce mycotoxin exposure but also to support key physiological functions, particularly liver health and immune performance. He suggested that such measures may provide benefits during both acute contamination events and long-term exposure scenarios. The Mycofix® portfolio includes a range of products tailored to different contamination risks and regional requirements. For more information, readers can access the latest World Mycotoxin Survey. For references, contact editorial@perendale.co.uk 14 August 2026