The term “mycotoxin” is derived from the Greek word “mykes” meaning fungus (mould), and the Latin word “toxicum” meaning poison; as such, mycotoxins refer to poisons produced by fungi (Iqbal et al., 2016a, 2016b; Mwihia et al., 2020). The intoxications that occur in animals and people due to ingesting one or more mycotoxins into the body is referred to as mycotoxicosis, and can cause sickness or death (Gallo et al., 2015; Patil and Kakde, 2017). The primary health impact of mycotoxin exposure is due to chronic poisoning (Krogh, 1969). Toxigenic fungi can be categorized into two groups: field fungi (e.g., Alternaria and Fusarium spp.), which access the crop during the development of the plant, or storage fungi (e.g., Aspergillus spp., Penicillium spp.), which mostly contaminate the crop post-harvest (Magan and Lacey, 1984; Kebede et al., 2020). Moreover, poor hygienic practices during transportation and storage, such as high temperature, heavy rain, and high moisture content, are the main predisposing factors which play an important role on mycotoxins production (Kebede et al., 2020). Detecting these fungi in feed or its raw materials does not necessarily mean that mycotoxins will contaminate them (Oliveira and Vasconcelos, 2020). These fungi invade stored feed crops and other farm products used in animal feed production, mostly maize, groundnuts and cotton (Thompson and Henke, 2000; Mwihia et al., 2018).

Mycotoxins have diverse structures with varying biological effects in their chemical form, which can cause cancer, mutation, neural damage, or suppression of the immune system in humans (Ahmed et al., 2017; Shahba et al., 2021). Aspergillus, Penicillium, and Fusarium are the most common genera of mycotoxigenic fungus, but Trichoderma, Trichothecium, and Alternaria are also present as food contaminants or plant pathogens, causing huge economic and health impacts (Richard, 2007; Viegas et al., 2015; Albero et al., 2022). At present, about 300 to 400 mycotoxin types have been identified (Berthiller et al., 2007), with aflatoxins (AFs) (AFB1, B2, G1, and G2) and fumonisins (FBs) (FB1, FB2, and FB3) being the most significant (Pitt, 2000; Cimbalo et al., 2020). They show a great structural diversity, resulting in different chemical and physicochemical properties. Generally, mycotoxins are chemically and thermally stable compounds, capable of surviving storage and most cereal production processes (Köppen et al., 2010). Aside from AFs and FBs, ochratoxin A (OTA), zearalenone, and trichothecenes (THs) are also significant (Bryden, 2012; Marroquín-Cardona et al., 2014; Cimbalo et al., 2020).

Contamination of food items with dangerous and unfavorable compounds restricts their trade in international markets (Frenich et al., 2014). Contamination by mycotoxins can cause degradation and decrease the dietary value of the feed materials (Chukwudi et al., 2021). Animal feed contamination with mycotoxins due to mold growth on living and stored plants presents a global challenge to farmers (Nakavuma et al., 2020). Essentially, raw materials for compound food and feeds are good substrates for mold growth; the Food and Agricultural Organization (FAO) estimated up to 25% of the world’s food crops and a significant proportion of the world’s animal feedstuff are contaminated by mycotoxins (Nakavuma et al., 2020).

A variety of environmental factors influence the presence of mycotoxins in food (Koletsi et al., 2021). Climate is the key driver of mycotoxin production by altering environmental conditions that affect fungal growth and toxin biosynthesis (Marroquín-Cardona et al., 2014). Rising global temperatures create favorable conditions for toxigenic fungi such as Aspergillus and Fusarium, leading to increased production of mycotoxins (Medina et al., 2017). Changes in precipitation patterns, such as prolonged droughts, followed by sudden rainfall, create stress conditions that weaken crops, making them more susceptible to fungal invasion, enhancing mycotoxin contamination in agricultural produce (Battilani et al., 2016). Additionally, climate change can lead to shifts in fungal populations, where non-toxigenic species are outcompeted by toxigenic strains, further exacerbating the risk of mycotoxin contamination in new geographical areas (Moretti et al., 2019). Post-harvest conditions are also affected, as increased temperatures and humidity levels in storage facilities create ideal environments for fungal growth and secondary contamination. Inadequate drying and poor storage conditions under warmer climates contribute to the persistence and proliferation of mycotoxins in stored food and feed products (Paterson and Lima, 2010). Preventing this contamination is critical because various products might be contaminated along the animal production chain, and it is difficult to identify the infected product (Magnoli et al., 2019).

The occurrence of mycotoxin in livestock was emphasized after the epidemics of aflatoxicosis in the 1960s in farm-reared turkeys (Meleagris gallopavo) in the UK and rainbow trout (Oncorhynchus mykiss) in the USA (Monson et al., 2015; Gonçalves et al., 2018). The source of contamination was found to be raw materials like peanut meal for turkeys and cottonseed meal for trout used in feed formulation (Wolf and Jackson, 1963; Kumar et al., 2013). Mycotoxin in fish feeds (henceforth referred to as aquafeed in this paper) is a significant concern, particularly in tropical climates and developing nations where farmers frequently produce aquafeeds under unsuitable conditions, including incorrect milling and storage (Marijani et al., 2019). To regulate mycotoxins in food, nodal agencies like the Food and Drug Administration of the USA (FDAF, 2021) and the European Commission [European Commission (EC), 2006] have set regulations for storage and maximum residual limits (MRLs) (Chong, 2022). A report from the Food and Agriculture Organization of the United Nations (Food and Agriculture Organization, 2003) states that the establishment of regulations on mycotoxins can be influenced by scientific factors such as data on the occurrence of mycotoxin in different commodities, including the toxicity of mycotoxin and their effects, the detection and analytical methods for mycotoxins, and the legislative elements regarding the control of mycotoxins. As research on mycotoxins in aquafeeds develops in response to the expanding health concerns, scientists face information constraints that may stymie creative investigation and scholarly collaboration. Conventional literature review studies are often performed to understand the extent of existing knowledge in a given domain (e.g., mycotoxins in aquafeeds). For instance, Matejova et al. (2017) reviewed the effects of mycotoxins on cultured fish. Marijani et al. (2019) reviewed the fungal and mycotoxin contamination of aquafeed, feed ingredients, and their effects on fish health. Oliveira and Vasconcelos (2020) reviewed the most important mycotoxins found in crops and in finished aquafeed, their effects on the health of fish and humans, and their regulations in the European Union.

Although these studies are relevant and provide valuable insights, they do not encompass the full scope of knowledge and research trends on mycotoxins in aquafeeds. This limitation is expected given the extensive and growing body of research in this area. The conventional study review process may be too subjective to fully capture the body of knowledge on mycotoxins in aquafeeds since it draws from a proportion of existing published research and may not capture the whole of the knowledge on the topic. This is because conventional review studies fail to accurately and thoroughly connect various elements within the literature (Amin et al., 2022). Consequently, it is crucial to develop and use an approach that allows scientists to gather essential information from multiple sources simultaneously. This limitation could be addressed by a scientometric review approach using a software tool. In order to produce statistical indexes that show research dynamics and emerging trends, scientometric reviews statistically analyze the relationships between various scientific publications (Andriamamonjy et al., 2019). This study intends to conduct a combination of a conventional review of mycotoxins in aquafeeds and a scientometric analysis of bibliographic records published on the topic up to 2023. Specifically, the goals of this study are to (I) identify the global publication trend on mycotoxin in aquafeed; (II) identify the most influential countries, authors, journals, articles, and keywords in the area of mycotoxin in aquafeed; (III) provide an overview of mycotoxin occurrence in aquafeeds; and (IV) identify the gaps and future research directions concerning this topic.

This research was based on a scientometric analysis of studies on mycotoxins in aquafeed published between 1982 and 2023. To achieve the research objectives, academic publications within the field were identified in the Web of Science (WoS) database, the most reliable and prominent data source comprising the leading journals worldwide (Chadegani et al., 2013; Iftikhar et al., 2023). Both the Web of Science Core Collection (WoSCC) and Scopus are popular search tools for bibliometric analysis. Considering the long history and wide recognition of the WoSCC, as well as its rich citation indexing capabilities, we selected the WoSCC as the search tool (Li et al., 2024). WoSCC is widely recognized as a reliable source for bibliometric research, encompassing the Science Citation Index Expanded (SCI-EXPANDED), Social Sciences Citation Index (SSCI), Arts and Humanities Citation Index (A&HCI), Conference Proceedings Citation Index-Science (CPCI-S), Conference Proceedings Citation Index-Social Science and Humanities (CPCI-SSH), and Emerging Sources Citation Index (ESCI) (Yan et al., 2024). Therefore, the WoS database was used as the source of information in this study. It contains an extensive metadata collection, including author lists, abstracts, references, citation counts, organizations, journal impact factors, and nations (Gaviria-Marin et al., 2019; Wilson et al., 2021).

The search string was constructed using Boolean operators (OR and AND), an asterisk (*) symbol, and quotation marks (“”) in the Topics search (TS) of the WoSCC database. The asterisk symbol was used to account for variations in keywords, and the quotation marks were used to ensure that the keywords were interpreted with exact meanings. TS = (“Mycotoxin*” OR “Mycotoxicosis” OR “Aflatoxin*” OR “AFB1” OR “Aflatoxicosis” OR “Zearalenone*” OR “Ochratoxin*” OR “Fumonisin*” OR “T-2 toxin” OR “Patulin” OR “Trichothecene*” OR “Deoxynivalenol” OR “Vomitoxin”) AND TS = (“Aquafeed*” OR “Shrimp feed*” OR “Aquaculture feed*” OR “Aquafeed Ingredient*” OR “Aquaculture” OR “Aqua farming” OR “Aquafeed”). After removing the duplicated and irrelevant literature, 181 papers were selected and used for further bibliometric and visualized analysis.

The types of documents that were considered for inclusion in the study were journal articles and conference papers. The source types “journal” and “conference proceedings” were selected. The “year of publication” limitation was set from “1982 to 2023” and there was no language restriction. No grey literature was included in this study. To uphold data integrity throughout our bibliometric analysis, we implemented a meticulous three-step process encompassing data cleaning, duplicate removal, and validation. Initially, we standardized author names, institutional affiliations, and keywords to address inconsistencies and variations, ensuring uniformity across the dataset. Subsequently, we identified and eliminated duplicate records to prevent redundancy and potential skewing of results. Finally, we conducted a thorough cross-verification of the dataset to confirm the accuracy of publication counts and citation metrics. These steps align with established best practices in bibliometric research, as highlighted in recent literature. After applying these conditions, a total of 181 records were maintained.

The records were saved in the text files (.txt) files for further evaluation using appropriate computer software. The extracted raw data was mapped using VOSviewer (Van Eck and Waltman, 2010) and Biblioshiny (Aria and Cuccurullo, 2017). VOSviewer is a mapping tool that is easily available, based on open source software, utilized in various disciplines, and recommended by scientists (van Eck and Waltman, 2010; Wong, 2018). Biblioshiny is an open source tool programmed in R and designed to perform extensive scientific analysis. It enables creating thematic maps based on information found in the dataset, such as institutions, countries and keywords (Aria and Cuccurullo, 2017). The VOS viewer bibliometric analysis software was preferred for this study over other similar software mainly because of its efficiency in analyzing research outputs in clusters. Additionally, VOS viewer constructs and offers a visual representation of research networks in bibliometric analysis (Obileke et al., 2020; George et al., 2021). As a result, the objectives of this study are effectively achieved through the application of VOSviewer and Biblioshiny. The .txt files that were generated were imported into VOSviewer, and additional analysis was carried out while ensuring that the data’s integrity and consistency were not compromised. The publications types and sources, keywords, authors with the most citations, and the countries and institutions were all assessed in the bibliographic analysis. Statistical results were reported in tables and figures, while their relationships and term co-occurrence were shown using maps. The flowchart of the scientometric review process is shown in Figure 1. However, for a more detailed and better grasp of the topic, a traditional review of existing body of literature related to mycotoxins in aquafeed was performed in this study. Emphasis was placed on the occurrence of mycotoxins in aquafeeds, specifically on documented mycotoxin occurrence in aquafeeds, raw materials used in aquafeed, and the risk of contamination by various mycotoxins. Additionally, the detection methods for mycotoxins in aquafeeds and the maximum permissible limits of mycotoxins in aquafeed and animal feed were identified. As a result, this paper combines scientometric analysis with a traditional literature review to better describe the main research interest and focus of mycotoxins in aquafeed.

The term mycotoxin was coined in 1962 in response to an enormous veterinary crisis near London, England, during which approximately 100,000 turkey poults perished. Scientists determined that this peculiar turkey X illness was caused by a peanut (groundnut) meal contaminated with secondary metabolites from Aspergillus flavus (aflatoxins), alerting them to the potential lethality of other hidden mold substances (Bennett and Klich, 2003). While all mycotoxins originate from fungi, not all fungal metabolites are toxic substances. The concentration of both the metabolite and its target is crucial. Mycotoxins produced by fungi are detrimental to vertebrates and other animal species even at low doses. They are distinct from ethanol or other low-molecular-weight fungal metabolites, which are lethal only at high doses (Bennett, 1987). To the best of our knowledge, this is the first comprehensive study that has attempted to summarize the mycotoxin research trends in aquafeed using a combination of scientometric and conventional review approaches.

Based on statistics and visualization tools, bibliometric analysis has emerged as a way to display a specific topic’s knowledge structures and evolutionary patterns (Devos and Menard, 2019; Chaudhuri et al., 2020). It can measure author and institution productivity, map international collaboration networks, and investigate geographic dispersion using published data to detect research trends and hot subjects (Lu et al., 2021; Ou et al., 2022). Various tools are available for bibliometric analysis, each with its own advantages and disadvantages (Choudhri et al., 2015; Karanatsiou et al., 2017; Chen, 2020; Markscheffel and Schröter, 2021).

Mycotoxins pose a significant concern to both human and animal health and welfare. This field requires more study due to the diminishing publication growth rate despite growing mycotoxin concerns in the global feed market. Zyoud (2019) conducted a bibliometric study from Scopus in 2019 and found 9,845 articles on aflatoxin. In contrast, the current study searched WoS for papers addressing mycotoxins in farmed aquafeed and found 181 articles. The low number of documents underscores the need for additional research on mycotoxins in aquafeed. Nevertheless, the documents and the top journals publishing the work on mycotoxin in aquafeed play an important role in providing the scientific evidence needed by researchers, industry players, and policymakers in tackling mycotoxin contamination in feeds and feed ingredients.

The bibliometric analysis reveals a significant underrepresentation of African countries in mycotoxin research within the aquaculture sector, reflecting broader systemic challenges that hinder scientific output on the continent. This can be attributed to challenges such as the chronic underfunding of research and development, which limits access to essential infrastructure, equipment, and long-term project support (Akuru, 2019). Additionally, a shortage of specialized human capital, exacerbated by brain drain, further constrains the capacity of institutions to engage in high-quality research (Sheikheldin and Mohamed, 2021). Fragmented linkages among universities, research institutes, and industry also contribute to low research productivity by hindering interdisciplinary collaboration and knowledge transfer (Okoroigwe et al., 2022). Yet collaboration plays a critical role in enhancing scientific knowledge through the exchange of expertise, joint experimentation, and shared access to resources (Bégin-Caouette et al., 2023). The low level of collaboration in Africa, therefore, not only limits co-authored publications but also stifles opportunities for innovation and broader scientific impact in addressing pressing issues like mycotoxin contamination.

Based on our conventional literature review, we see evidence for the occurrence of mycotoxins in aquafeed and feed ingredients in various countries. The contamination of aquafeed with mycotoxins appears to be common and a worldwide issue, but the type and prevalence of mycotoxin contamination in feed appears to highly depend on the geographical region. This might be due to the difference in climatic conditions of various regions, the type of samples analyzed, or the methodology used to identify mycotoxins, among other factors. According to Moretti et al. (2019), climate change has the potential to have a dramatic impact on the growth, dispersal, and production of mycotoxin in fungi. Different regions have different climatic conditions (Milani, 2013), and mycotoxin occurrence is more prevalent in regions dominated by warm climatic conditions. Increased temperatures favor the proliferation of heat-tolerant mycotoxigenic fungi, particularly aflatoxin-producing Aspergillus species. While Penicillium species, producing OTA and patulin, are typically associated with mycotoxin production in temperate climates, Aspergillus species, producing AFs and OTA, are more prevalent in tropical and subtropical regions due to their ability to thrive at elevated temperatures and lower water activity levels (Zingales et al., 2022).

Moreover, the findings indicate that mycotoxin contamination is more prevalent in developing countries (Barbosa et al., 2013; Fallah et al., 2014), which might be due to the lack of stringent regulations and monitoring and surveillance due to weak institutional efforts (Chilaka et al., 2022). Moreover, farmers in developing countries often produce aquafeeds under unsuitable conditions, including incorrect milling and storage (Marijani et al., 2019), which could increase the chances of mycotoxin contamination.

The detrimental effects of mycotoxins to fish and to humans have necessitated the establishment of stringent international regulations on mycotoxins, and various permissible limits have been set. Although mycotoxin legislation around the world varies, the lack of a clear approach has resulted in variations in standards, particularly regarding the maximum permissible levels imposed among countries and international organizations. Furthermore, regulations may not exist or may exist but not always be followed in many developing countries, especially where there are problems with food availability (Poroșnicu et al., 2023).

Despite the growing body of research on mycotoxins in aquafeed, several gaps remain that limit the full understanding of this issue. Research reveals the global prevalence of mycotoxin contamination, especially in developing countries, but lacks a more detailed examination of specific regions and their unique vulnerabilities. Additionally, while the detrimental effects of mycotoxins on aquaculture species are acknowledged, there is limited focus on species-specific research, particularly in terms of tolerance and sensitivity to different mycotoxins. Another significant gap lies in the inconsistent regulations across countries, where a deeper analysis of the impact of these regulatory variations on aquafeed trade and local aquaculture industries, especially in nations with weaker institutional frameworks, is needed. Moreover, the existing research does not sufficiently address the role of climate change, which may exacerbate mycotoxin contamination, particularly in tropical regions where favorable conditions for toxin production exist. Furthermore, while the research highlights the negative effects of mycotoxins to fish and to human, practical strategies for mitigation, such as detoxification methods or the use of alternative feed ingredients, are not discussed in enough detail.

Future research should focus on species-specific mycotoxin tolerance to provide tailored solutions for different aquaculture species. Regional studies that dive deeper into the specific conditions of developing countries can offer more nuanced insights into the factors contributing to mycotoxin occurrence. The harmonization of global regulations on permissible mycotoxin levels is another key area for future research. Priority should be given to aligning regulations across key aquaculture-producing regions, such as the African Union (AU), Association of Southeast Asian Nations (ASEAN), and Latin America’s MERCOSUR bloc. Leveraging existing global frameworks like the Codex Alimentarius, particularly its Code of Practice for the Prevention and Reduction of Mycotoxin Contamination in Cereals, could help standardize permissible limits, analytical protocols, and surveillance strategies.

As climate change is expected to alter environmental conditions, its influence on the prevalence and dynamics of mycotoxin contamination in aquafeed warrants further exploration. Developing and evaluating practical, cost-effective mitigation strategies, such as detoxification techniques or the introduction of alternative feed ingredients, is also crucial. Future studies should explore and validate interventions such as the use of mycotoxin binders (e.g., bentonite, activated carbon), biological detoxification through fermentation, and biotransformation using microbial enzymes capable of degrading aflatoxins and other common mycotoxins. These approaches are particularly relevant for small-scale and resource-limited producers in developing countries, where access to advanced technology is limited.

Additionally, interdisciplinary research networks that bring together experts in toxicology, aquaculture, feed technology, and policy could foster more comprehensive solutions to manage the mycotoxin challenge. These efforts are necessary to safeguard both the aquaculture industry and the populations reliant on fish as a key food source, particularly in the most vulnerable regions.

Despite its comprehensive scope, the current study was not without its limitations. The first limitation was the inability of the bibliometric software to distinguish between articles focusing on human and animal models. Secondly, a few authors in the data may have duplicate names, and some may have held honorary or part-time positions at different universities. Additionally, the terms “mycotoxin” and “mycotoxins” have been treated as two distinct terms because the program cannot distinguish the difference in writing. Moreover, VOSviewer’s visualizations are mostly limited to network graphs, and it does not support other types of visual representations like geospatial maps, tree maps, spectrograms, or data different from the bibliography dataset (Bukar et al., 2023). In recent years, software writers have gradually improved these deficiencies, and appropriate improvements can be used to reduce the impact of these limitations. In future research, we will further revise these deficiencies, strengthen the analysis, and obtain more detailed and accurate research conclusions.

The bibliometric analysis relied solely on a single scholarly database (WoS). As WoS consistently updates its database, data downloaded for a specific time frame may not include other publications added after the time frame. Furthermore, while WoS is extensive, it may not capture all relevant research outputs, particularly from non-English sources or studies indexed in other major databases such as Scopus, Pubmed and Google Scholar. Future research could address these limitations by incorporating data from additional databases, such as Scopus, Pubmed, and Google Scholar, to provide a more comprehensive and global perspective on research in mycotoxins on aquafeed.

This study conducted a combined bibliometric analysis and conventional review of global mycotoxin research in aquafeed. The study’s findings showed that publications on the topic have gradually expanded over the last 10 years, with substantial international participation. It reveals several publications in this field, from various countries, and published in various journals. The publications on mycotoxin research in aquafeed have garnered several citations, depicting the scientific impact of these studies. The scientometric analysis mapped research trends using statistical indices, revealing knowledge gaps and emerging priorities. From the conventional review, there is evidence of the occurrence of mycotoxins in aquafeed and feed ingredients in various countries and regions, indicating that contamination of aquafeed with mycotoxins is a common and global problem. Mycotoxin occurrence is more prevalent in regions dominated by warm climatic conditions, especially in developing countries, which lack stringent regulations, monitoring, and surveillance due to weak institutional efforts. The detrimental effects of mycotoxins have necessitated the establishment of international regulations and permissible limits. However, standards, particularly regarding the maximum permissible levels imposed, vary significantly across countries and international organizations.

This study connects various elements within the literature on mycotoxin in aquafeeds by gathering essential information from sources that are most reliable. The most important studies in this discipline are highlighted in this paper, which will likely become the benchmark for mycotoxin research and regulations in the future. Although significant research has been conducted on mycotoxins in aquafeed, important gaps remain. These include a lack of regional specificity, limited species-specific studies on mycotoxin tolerance, and inconsistent regulatory frameworks across countries. Research also overlooks the role of climate change in exacerbating mycotoxin contamination and lacks practical mitigation strategies. Future research should focus on species-specific tolerance, regional analyses, harmonization of regulations, and the impact of climate change. Moreover, developing cost-effective mitigation techniques and fostering interdisciplinary research networks will be crucial for managing mycotoxins and safeguarding aquaculture industries, especially in vulnerable regions.