Risk assessment for mycotoxin contamination in fish feeds in Europe

High-Resolution Magic-Angle Spinning Nuclear Magnetic Resonance Identifies Impairment of Metabolism by T-2 Toxin, in Relation to Toxicity, in Zebrafish Embryo Model

Among the widespread trichothecene mycotoxins, T-2 toxin is considered the most toxic congener. In the present study, we utilized high-resolution magic-angle spinning nuclear magnetic resonance (HRMAS NMR), coupled to the zebrafish (Danio rerio) embryo model, as a toxicometabolomics approach to elucidate the cellular, molecular and biochemical pathways associated with T-2 toxicity. Aligned with previous studies in the zebrafish embryo model, exposure to T-2 toxin was lethal in the high parts-per-billion (ppb) range, with a median lethal concentration (LC50) of 105 ppb. Exposure to the toxins was, furthermore, associated with system-specific alterations in the production of reactive oxygen species (ROS), including decreased ROS production in the liver and increased ROS in the brain region, in the exposed embryos. Moreover, metabolic profiling based on HRMAS NMR revealed the modulation of numerous, interrelated metabolites, specifically including those associated with (1) phase I and II detoxification, and antioxidant pathways; (2) disruption of the phosphocholine lipids of cell membranes; (3) mitochondrial energy metabolism, including apparent disruption of the tricarboxylic acid (TCA) cycle, and the electron transport chain of oxidative phosphorylation, as well as "upstream" effects on carbohydrate, i.e., glucose metabolism; and (4) several compensatory catabolic pathways. Taken together, these observations enabled development of an integrated, system-level model of T-2 toxicity in relation to human and animal health.

Mycotoxins in food: Occurrence, health implications, and control strategies-A comprehensive review

Mycotoxins are secondary metabolites produced by various filamentous fungi, including Aspergillus, Fusarium, Penicillium, Alternaria, Claviceps, Mucor, Trichoderma, Trichothecium, Myrothecium, Pyrenophora, and Stachybotrys. They can contaminate various plants or animal foods, resulting in a significant loss of nutritional and commercial value. Several factors contribute to mycotoxin production, such as humidity, temperature, oxygen levels, fungal species, and substrate. When contaminated food is consumed by animals and humans, mycotoxins are rapidly absorbed, affecting the liver, and causing metabolic disorders. The detrimental effects on humans and animals include reduced food intake and milk production, reduced fertility, increased risk of abortion, impaired immune response, and increased occurrence of diseases. Therefore, it is imperative to implement strategies for mycotoxin control, broadly classified as preventing fungal contamination and detoxifying their toxic compounds. This review aims to discuss various aspects of mycotoxins, including their occurrence, and risk potential. Additionally, it provides an overview of mycotoxin detoxification strategies, including the use of mycotoxin absorbents, as potential techniques to eliminate or mitigate the harmful effects of mycotoxins and masked mycotoxins on human and animal health while preserving the nutritional and commercial value of affected food products.

Risk assessment of exposure to 12 kinds of mycotoxins through consumption of Pericarpium Citri Reticulatae collected from Three Gorges Reservoir area of China

A method for simultaneous determination of 12 mycotoxins in Pericarpium Citri Reticulataeby HPLC-MS/MS was established to analyze the residues of mycotoxins, inwhich from Three Gorges Reservoir area of China, including AFB1, AFB2, AFG1, AFG2, T-2, FB1, FB2, FB3, ZEN, OTA, OTB and DON.In addition, a probabilistic assessment model based on Monte Carlo simulation method was established in combination with pollution data, and the health risk assessment was carried out by the exposure limit method (MOE).The results showed that the method with strong specificity, good linearity and accurate recovery was established and could be used for the determination of 12 mycotoxins in Pericarpium Citri Reticulatae.In general, the total pollution rate of different degrees of pollution in the 36 batches of Pericarpium Citri Reticulatae sampleswas 75 %. It should be noted thatthe proportion of positive samplescontaminated by one toxin was the highest (59.26 %), and the detection rate of FB3 in Pericarpium Citri Reticulataewas the highest (66.67%), followed by AFG1 (44.44 %), indicating that the medicinal material polluted by AFG1 and AFB3 alone or simultaneously was more serious. Specifically, the detection rate of mycotoxins in Chongqing was the highest (92.31%) on account of the high temperature and humidity in Chongqing, followed by Southeast of Sichuan (83.33%) and West of Hubei (45.45%).On the other hand, the MOE of AFB1 and AFB2 calculated were both greater than 10000, indicating that the health risk of AFB1 and AFB2 exposure caused by taking Pericarpium Citri Reticulatae was low, but the risk of high intake population was higher than that of conventional intake population, which needed to be paid attention to. This study can provide a reference for the safety assessment of clinical medication of Pericarpium Citri Reticulatae inThree Gorges Reservoir area.

Cellular and molecular mechanisms of aflatoxin B1-mediated neurotoxicity: The therapeutic role of natural bioactive compounds

Aflatoxin B1 (AFB1), a dietary toxin from the mold Aspergillus species, is well acknowledged to elicit extra-hepatic toxicity in both animals and humans. The neurotoxicity of AFB1 has become a global public health concern. Contemporary research on how AFB1 enters the brain to elicit neuronal dysregulation leading to noxious neurological outcomes has increased greatly in recent years. The current review discusses several neurotoxic outcomes and susceptible targets of AFB1 toxicity at cellular, molecular and genetic levels. Specifically, neurotoxicity studies involving the use of brain homogenates, neuroblastoma cell line IMR-32, human brain microvascular endothelial cells, microglial cells, and astrocytes, as well as mammalian and non-mammalian models to unravel the mechanisms associated with AFB1 exposure are highlighted. Further, some naturally occurring bioactive compounds with compelling therapeutic effects on AFB1-induced neurotoxicity are reviewed. In conclusion, available data from literature highlight AFB1 as a neurotoxin and its possible pathological contribution to neurological disorders. Further mechanistic studies aimed at discovering and developing effective therapeutics for AFB1 neurotoxicity is warranted.

Prenatal Fumonisin Exposure Impairs Bone Development via Disturbances in the OC/Leptin and RANKL/RANK/OPG Systems in Weaned Rat Offspring

The goal of the current study was to examine the effects of prenatal exposure to fumonisins (FBs) on bone properties and metabolism in weaned rat offspring divided into groups intoxicated with FBs at either 0 (the 0 FB group), 60 (the 60 FB group), or 90 mg/kg b.w. 0 (the 90 FB group). Female and male offspring exposed to FBs at a dose of 60 mg/kg b.w. had heavier femora. Mechanical bone parameters changed in a sex and FBs dose-dependent manner. Growth hormone and osteoprotegerin decreased in both sexes, regardless of FBs dose. In males osteocalcin decreased, while receptor activator for nuclear factor kappa-Β ligand increased regardless of FBs dose; while in females changes were dose dependent. Leptin decreased in both male FBs-intoxicated groups, bone alkaline phosphatase decreased only in the 60 FB group. Matrix metalloproteinase-8 protein expression increased in both female FBs-intoxicated groups and decreased in male 90 FB group. Osteoprotegerin and tissue inhibitor of metalloproteinases 2 protein expression decreased in males, regardless of FBs dose, while nuclear factor kappa-Β ligand expression increased only in the 90 FB group. The disturbances in bone metabolic processes seemed to result from imbalances in the RANKL/RANK/OPG and the OC/leptin systems.

Dietary beauvericin and enniatin B exposure cause different adverse health effects in farmed Atlantic salmon

The extensive use of plant ingredients in novel aquafeeds have introduced mycotoxins to the farming of seafood. The emerging enniatin B (ENNB) and beauvericin (BEA) mycotoxins have been found in the novel aquafeeds and farmed fish. Little is known about the potential toxicity of ENNs and BEA in farmed fish and their feed-to-organ transfer. Atlantic salmon (Salmo salar) pre-smolt (75.3 ± 8.10 g) were fed four graded levels of spiked chemical pure ENNB or BEA feeds for three months, in triplicate tanks. Organismal adverse health end-point assessment included intestinal function (protein digestibility), disturbed hematology (red blood cell formation), bone formation (spinal deformity), overall energy use (feed utilization), and lipid oxidative status (vitamin E). Both dietary BEA and ENNB had a low (<∼0.01%) transfer to organs (kidney > liver > brain > muscle), with a higher transfer for ENNB compared to BEA. BEA caused a growth reduction combined with a decreased protein digestion and feed conversion rate- ENNB caused a stunted growth, unrelated to feed utilization capacity. In addition, ENNB caused anemia while BEA gave an oxidative stress response. Lower bench-mark dose regression assessment showed that high background levels of ENNB in commercial salmon feed could pose a risk for animal health, but not in the case of BEA.

Mycotoxins in Seafood: Occurrence, Recent Development of Analytical Techniques and Future Challenges

The co-occurrence of mycotoxigenic fungi and mycotoxins in aquatic food commodities has recently become a source of severe worldwide food insecurity since these toxicants may damage human health. The consumption of aquatic food itself represents a relatively novel and non-negligible source of mycotoxins. Mycotoxins in seafood lead to important human genotoxins, carcinogens, and immunosuppressors. Consequently, it is crucial to quantify and characterize these contaminants in aquatic food products subject to extensive consumption and develop new regulations. The present paper provides an overview of recent advancements in liquid chromatography and mass spectrometry and the coupling of these techniques for identifying and characterizing mycotoxins in various fresh, comestible, and treated marine products. The disposable data display that a multiplicity of fungal species and further mycotoxins have been detected in seafood, comprising aflatoxins, ochratoxins, fumonisins, deoxynivalenol, zearalenone, and trichothecenes. In addition, a wider and up-to-date overview of global occurrence surveys of mycotoxin occurrence in seafood in 2017–2022 is explored. In this regard, the predominant occurrence of enniatins has been documented in seafood products. Likewise, special attention has been given to current EU seafood legal and existing national regulations of mycotoxins in seafood. In this way, rigorous national and international guidelines are needed for palpable and effective measures in the future. Nevertheless, controlling mycotoxins in aquatic foods is an ambitious aim for scientists and industry stakeholders to ensure sustainable global food safety.

The protective effects of Saccharomyces cerevisiae on the growth performance, intestinal health, and antioxidative capacity of mullet (Liza ramada) fed diets contaminated with aflatoxin B1

Plant protein ingredients are increasingly included in mullet feeds and are expected to be contaminated with mycotoxins (AFB1). Thus, this study investigated the protective role of Saccharomyces cerevisiae against oxidative stress and hepato-renal malfunction induced by AFB1 contamination in mullets. Four diets were formulated, where the first was kept as the control diet, and the second was supplemented with S. cerevisiae at 5 × 106 cells/g. The third diet was supplied with AFB1 at 1 mg/kg, and the fourth was supplemented with S. cerevisiae and AFB1. Mullet fed the control or both AFB1 and S. cerevisiae (yeast/AFB1) had similar FBW, WG, SGR, and FCR (P˃0.05). Mullet treated with S. cerevisiae without AFB1 contamination showed the highest FBW, WG, and SGR (P<0.05), while fish in the AFB1 group had lower FBW, WG, and SGR and higher FCR than fish in the control and yeast/AFB1 groups (P<0.05). Using yeast with AFB1 prevented pathological hazards and improved intestinal structure. Further, yeast combined with AFB1 reduced the degenerative changes and enhanced the histological structure except for a mild inflammatory reaction around the bile duct. Fish in the control or yeast/AFB1 group had higher HB, PCV, RBCs, and WBCs than fish in the AFB1 group (P<0.05). Fish fed the control, or the yeast/AFB1 diets had similar total protein and albumin levels with higher values than fish contaminated with AFB1 (P<0.05). Fish fed the control and yeast/AFB1 diets had similar ALT, AST, urea, and creatinine levels (P˃0.05) and were lower than fish contaminated with AFB1. Additionally, fish fed the control and yeast/AFB1 diets had similar CAT, GPx, SOD, and MDA (P˃0.05) and were lower than fish contaminated with AFB1 (P<0.05). In conclusion, incorporating S. cerevisiae ameliorated the negative impacts of AFB1 toxicity on mullets’ growth, hepato-renal function, and antioxidative capacity.

Enniatin B and beauvericin affect intestinal cell function and hematological processes in Atlantic salmon (Salmo salar) after acute exposure

Unintentional use of mold-infested plant-based feed ingredients are sources of mycotoxins in fish feeds. The presence of the emerging mycotoxins ENNB and BEA in Norwegian commercial fish feeds and plant-based feed ingredients has raised concerns regarding the health effects on farmed Atlantic salmon (Salmon salar). Atlantic salmon pre-smolts were exposed to non-lethal doses of BEA and ENNB (ctrl, 50 and 500 μg/kg feed for 12 h), after which total RNA sequencing of the intestine and liver was carried out to evaluate gut health and identify possible hepatological changes after acute dietary exposure. ENNB and BEA did not trigger acute toxicity, however ENNB caused the onset of pathways linked to acute intestinal inflammation and BEA exposures caused the onset of hepatic hematological disruption. The prevalence and concentration of ENNB found in today's commercial feed could affect the fish health if consumed over a longer time-period.

Urinary analysis reveals high Alternaria mycotoxins exposure in the general population from Beijing, China

Alternaria mycotoxins are of concern due to its adverse health effect, they affect various cereal crops and grain-based food along with modified forms that contribute to overall exposure. This study aimed to determine the frequency and level of exposure to Alternaria mycotoxins (tenuazonic acid, TeA; alternariol, AOH; alternariol monomethyl ether, AME; tentoxin, TEN; and altenuene, ALT) in human urine from Beijing adults. A total of 2212 urine samples were collected and analyzed for five mycotoxins using LC-ESI-MS/MS. More than 98% of the samples had at least one Alternaria mycotoxin detected. Among the mycotoxins, AME had the highest detection rate (96.0%), followed by TeA (70.5%). The calculated average daily intake values of AME (12.5 ng/kg b.w.) was 5 times the TTC value (2.5 ng/kg b.w.) set by the EFSA, indicating the potential health risks associated with mycotoxins. Immediate attention and subsequent actions should be taken to identify the sources of mycotoxins and the corresponding exposure pathways to humans in the investigated regions.

Fish feed can show genotoxic damage

The present study was carried out to evaluate the genotoxic potential of nutritional quality of feed, using erythrocytic nuclear abnormalities assay in Nile tilapia and its correlation with available nutrients and common fish growth biomarkers. For this, ten feeds commercialized in Brazil were assessed on digestibility and performance assays with triplicate groups. Venipuncture of the caudal vein for abnormalities analyzed was performed 102 days after the fish were fed with the commercial feed twice a day, to apparent satiation. Nuclear abnormalities were analyzed in blood smears. Principal component analysis and correlation matrix were used to carry out an exploratory analysis of correlation between frequency of abnormalities and performance parameters or available nutrients. The frequency of abnormalities in erythrocytes of Nile tilapia, fish performance, and digestibility were feed-dependent. It was observed correlations between the frequency of most abnormalities and performance parameters or content of nutrients. The frequency of kidney-shaped (6.23 ± 4.14), bud nuclei (2.99 ± 1.95), bridge nuclei (0.53 ± 0.50), and binuclei (0.43 ± 0.59) was the highest in fish that also presented the worst performance among all treatments and correlated with digestible methionine. Micronucleus frequency (0.33 ± 0.49) was higher in fish from the same group that presented depressed feed intake and lower available zinc. Only one group presented vacuolated nuclei and the frequency of this abnormality was correlated with available phosphorus. The frequency of abnormalities in erythrocytes is a fish sensitive indicator of health and plays an important role as a complementary tool in the assessment of fish feeding. The variation in the frequency of nuclear abnormalities in erythrocytes obtained among fish fed with the different feeds allows the assertion that they contained genotoxic factors.

Alimentary Risk of Mycotoxins for Humans and Animals

Mycotoxins can be found in many foods consumed by humans and animals. These substances are secondary metabolites of some fungi species and are resistant to technological processes (cooking, frying, baking, distillation, fermentation). They most often contaminate products of animal (beef, pork, poultry, lamb, fish, game meat, milk) and plant origin (cereals, processed cereals, vegetables, nuts). It is estimated that about 25% of the world's harvest may be contaminated with mycotoxins. These substances damage crops and may cause mycotoxicosis. Many mycotoxins can be present in food, together with mold fungi, increasing the exposure of humans and animals to them. In this review we characterized the health risks caused by mycotoxins found in food, pet food and feed. The most important groups of mycotoxins are presented in terms of their toxicity and occurrence.

Mycotoxins—Prevention, Detection, Impact on Animal Health

Mycotoxins are defined as secondary metabolites of some species of mold fungi. They are present in many foods consumed by animals. Moreover, they most often contaminate products of plant and animal origin. Fungi of genera Fusarium, Aspergillus, and Penicillum are most often responsible for the production of mycotoxins. They release toxic compounds that, when properly accumulated, can affect many aspects of breeding, such as reproduction and immunity, as well as the overall liver detoxification performance of animals. Mycotoxins, which are chemical compounds, are extremely difficult to remove due to their natural resistance to mechanical, thermal, and chemical factors. Modern methods of analysis allow the detection of the presence of mycotoxins and determine the level of contamination with them, both in raw materials and in foods. Various food processes that can affect mycotoxins include cleaning, grinding, brewing, cooking, baking, frying, flaking, and extrusion. Most feeding processes have a variable effect on mycotoxins, with those that use high temperatures having the greatest influence. Unfortunately, all these processes significantly reduce mycotoxin amounts, but they do not completely eliminate them. This article presents the risks associated with the presence of mycotoxins in foods and the methods of their detection and prevention.

Mycotoxins survey in feed materials and feedingstuffs in years 2015-2020

Mycotoxins are secondary metabolites produced by several fungi, mainly from Penicillium, Fusarium, and Aspregillus genera. They can contaminate many raw materials both in the field and during storage under very different conditions. This study aimed to evaluate mycotoxin contamination levels of raw materials and products for animals in Poland in the years 2015-2020. Producers, farmers, and veterinary doctors delivered a total of 3980 samples (642 maize samples, 2027 feed samples, 990 small grain samples, 142 maize silage samples and 179 TMR samples). Samples were analyzed for the occurrence of several mycotoxins, including aflatoxins, fumonisins, ochratoxin A, deoxynivalenol, nivalenol, T-2 toxin, H-2 toxin, and zearalenone. Trichothecenes, zearalenone, and fumonisins were determined using the LC-MS/MS technique. Ochratoxin A and aflatoxins were determined using the HPLC-FLD method. Deoxynivalenol and zearalenone were the most common contamination in maize samples (97.3% and 98.4%, respectively) and feed samples (99.7% and 100% samples, respectively). They were also present in all maize silage and TMR samples. The highest concentration levels of deoxynivalenol and zearalenone were 16,889 μg/kg in the wheat sample and 1420 μg/kg in the maize sample. Additionally, in 51 samples, mycotoxins level (mainly deoxynivalenol and zearalenone levels) was above recommended levels set by the European Union. The present study showed that both feeding and raw materials are contaminated by mycotoxins, often by more than one.

Research Progress on Fumonisin B1 Contamination and Toxicity: A Review

Fumonisin B1 (FB1), belonging to the member of fumonisins, is one of the most toxic mycotoxins produced mainly by Fusarium proliferatum and Fusarium verticillioide. FB1 has caused extensive contamination worldwide, mainly in corn, rice, wheat, and their products, while it also poses a health risk and is toxic to animals and human. It has been shown to cause oxidative stress, endoplasmic reticulum stress, cellular autophagy, and apoptosis. This review focuses on the current stage of FB1 contamination, its toxic effects of acute toxicity, immunotoxicity, organ toxicity, and reproductive toxicity on animals and humans. The potential toxic mechanisms of FB1 are discussed. One of the main aims of the work is to provide a reliable reference strategy for understanding the occurrence and toxicity of FB1.

Cytotoxicity of Mycotoxins Frequently Present in Aquafeeds to the Fish Cell Line RTGill-W1

In the last decades, the aquaculture industry has introduced plant-based ingredients as a source of protein in aquafeeds. This has led to mycotoxin contaminations, representing an ecological, health and economic problem. The aim of this study was to determine in the RTgill-W1 fish cell line the toxicity of fifteen mycotoxins of common occurrence in aquafeeds. To identify the most sensitive endpoint of toxicity, the triple assay was used. It consisted of three assays: alamarBlue, Neutral Red Uptake and CFDA-AM, which revealed the mitochondrial activity, the lysosomal integrity and the plasma membrane integrity, respectively. Most of the assayed mycotoxins were toxic predominantly at lysosomal level (enniatins, beauvericin, zearalenone, ochratoxin A, deoxynivalenol (DON) and its acetylated metabolites 15-O-acetyl-DON and 3-acetyl-DON). Aflatoxins B1 and B2 exerted the greatest effects at mitochondrial level, while fumonisins B1 and B2 and nivalenol were not toxic up to 100 µg/mL. In general, low toxicity was observed at plasma membrane level. The vast majority of the mycotoxins assayed exerted a pronounced acute effect in the fish RTgill-W1 cell line, emphasizing the need for further studies to ascertain the impact of mycotoxin contamination of fish feeds in the aquaculture industry and to establish safe limits in aquafeeds.

The Occurrence of Mycotoxins in Raw Materials and Fish Feeds in Europe and the Potential Effects of Deoxynivalenol (DON) on the Health and Growth of Farmed Fish Species-A Review

The first part of this study evaluates the occurrence of mycotoxin patterns in feedstuffs and fish feeds. Results were extrapolated from a large data pool derived from wheat (n = 857), corn (n = 725), soybean meal (n = 139) and fish feed (n = 44) samples in European countries and based on sample analyses by liquid chromatography/tandem mass spectrometry (LC-MS/MS) in the period between 2012-2019. Deoxynivalenol (DON) was readily present in corn (in 47% of the samples) > wheat (41%) > soybean meal (11%), and in aquafeeds (48%). Co-occurrence of mycotoxins was frequently observed in feedstuffs and aquafeed samples. For example, in corn, multi-mycotoxin occurrence was investigated by Spearman's correlations and odd ratios, and both showed co-occurrence of DON with its acetylated forms (3-AcDON, 15-AcDON) as well as with zearalenone (ZEN). The second part of this study summarizes the existing knowledge on the effects of DON on farmed fish species and evaluates the risk of DON exposure in fish, based on data from in vivo studies. A meta-analytical approach aimed to estimate to which extent DON affects feed intake and growth performance in fish. Corn was identified as the ingredient with the highest risk of contamination with DON and its acetylated forms, which often cannot be detected by commonly used rapid detection methods in feed mills. Periodical state-of-the-art mycotoxin analyses are essential to detect the full spectrum of mycotoxins in fish feeds aimed to prevent detrimental effects on farmed fish and subsequent economic losses for fish farmers. Because levels below the stated regulatory limits can reduce feed intake and growth performance, our results show that the risk of DON contamination is underestimated in the aquaculture industry.

Dietary garlic and chitosan enhanced the antioxidant capacity, immunity, and modulated the transcription of HSP70 and Cytokine genes in Zearalenone-intoxicated European seabass

The present study was performed to evaluate the toxic effects of feed-born zearalenone (ZEN) on antioxidative status, immunity, transcriptomic responses of European seabass, and the modulating roles of dietary garlic and/or chitosan powders. Fish (30.7 ± 0.6 g) were randomly arranged in five experimental groups (in triplicates), whereas the first group was fed on the control diet only without any supplements (control), and the second group was fed on the basal diet contaminated with ZEN (0.725 mg/kg diet). Three other groups were fed on ZEN-contaminated diets and simultaneously supplemented with garlic powder (GP) (30 g/kg diet) (ZEN + GP), chitosan powder (CH) (10 g/kg diet) (ZEN + CH), and a mixture of GP and CH (ZEN + GP + CH). Fish were fed on the experimental diets thrice a day for 4 weeks. Two-way ANOVA revealed a gradual decline in serum superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities in the ZEN group reaching their lowest levels at the 4th week. Contrariwise, malondialdehyde levels were markedly higher in the ZEN group reaching their highest values at the end of the experiment. A significant decline of total immunoglobulins (P < 0.05) was observed in the serum of the ZEN group, especially after the 4th week. Moreover, significant down-regulation of interleukin-4 (IL-4) and interleukin 1 beta (IL-1β) genes (P < 0.05) alongside significant up-regulation of tumor necrosis factor-alpha (TNF-α) and heat shock protein 70 (HSP70) genes (P < 0.05) in the liver and anterior kidney of ZEN-intoxicated group. Interestingly, dietary supplementation with GP and CH significantly attenuated ZEN-induced oxidative stress, immunosuppression, and modulated transcriptomic responses of ZEN-exposed fish. Moreover, combined dietary supplementation of both feed additives resulted in better effects than each one alone.

Evaluation of the mitigation efficacy of a yeast cell wall extract toward deoxynivalenol contaminated diet fed to turbot (Scophthalmus maximus)

Deoxynivalenol (DON) is one of the most common mycotoxins in animal feed worldwide and causes significant threats to the animal health. Increased use of plant ingredients in aquaculture feeds increased the risk of mycotoxin contamination. To evaluate the effects of dietary deoxynivalenol (DON) on growth performance, immune response and intestinal health of turbot and the mitigation efficacy of yeast cell wall extract (YCWE) toward DON, nine isonitrogenous and isolipidic diets were formulated: Diet 1 (control): No DON added; Diets 2-5 or Diets 6-9: 0.5 or 3.0 mg added DON/kg diet + 0%, 0.1%, 0.2%, or 0.4% YCWE, respectively. Results showed that Diet 6 (3 mg/kg DON, 0% YCWE) significantly decreased weight gain, specific growth rate and feed efficiency ratio of fish and reduced immunoglobulin M and complement 4 concentrations in serum. Fish fed Diet 6 presented morphological alterations, lower activity of superoxide dismutase, catalase and total antioxidant capacity but higher malondialdehyde content, lower claudin-4 and occludin expression but higher interleukin-1β expression in intestine. Besides, Diet 6 decreased the abundance of potential helpful bacteria but increased the abundance of potential pathogens in intestine. While, dietary YCWE, especially Diet 8 (3 mg/kg DON, 0.2% YCWE) and 9 (3 mg/kg DON, 0.4% YCWE), markedly improved growth performance and immune response and enhanced the intestinal health of turbot. In conclusion, dietary YCWE could mitigate the toxic effects induced by DON in turbot, and could be used as an effective strategy to control DON contamination in fish feed.

Individual and Combined Effects of Aflatoxin B1 and Sterigmatocystin on Lipid Peroxidation and Glutathione Redox System of Common Carp Liver

The purpose of the study was to evaluate the short-term effects of aflatoxin B1 (AFB1 100 µg/kg feed) and sterigmatocystin (STC 1000 μg/kg feed) exposure individually and in combination (100 μg AFB1 + 1000 μg STC/kg feed) on the parameters of lipid peroxidation and glutathione redox system both in biochemical and gene expression levels in one-year-old common carp. Lipid peroxidation parameters were slightly affected, as significant differences were observed only in conjugated diene and triene concentrations. Reduced glutathione content decreased more markedly by STC than AFB1 or AFB1+STC, but glutathione peroxidase activity did not change. Expression of gpx4a, gpx4b, gss, and gsr genes was down-regulated due to STC compared to AFB1 or AFB1+STC, while an induction was found as effect of AFB1+STC in the case of gpx4a, but down-regulation for gpx4b as compared to AFB1. Expression of the glutathione biosynthesis regulatory gene, gss, was higher, but glutathione recycling enzyme encoding gene, gsr, was lower as an effect of AFB1+STC compared to AFB1. These results are supported by the changes in the expression of transcription factors encoding genes, nrf2, and keap1. The results revealed that individual effects of AFB1 and STC on different parameters are synergistic or antagonistic in multi-toxin treatment.

Short-term effects of deoxynivalenol, T-2 toxin, fumonisin B1 or ochratoxin on lipid peroxidation and glutathione redox system and its regulatory genes in common carp (Cyprinus carpio L.) liver

The effects of a single oral dose of 1.82 mg kg^-1 bw of T-2 and HT-2 toxin (T-2), 1.75 mg kg^-1 bw deoxynivalenol (DON) and 15-acetyl DON, 1.96 mg kg^-1 bw fumonisin B₁ (FB₁) or 1.85 mg kg^-1 bw ochratoxin A (OTA) were investigated in common carp juveniles on lipid peroxidation, the parameters of the glutathione redox system including the expression of their encoding genes in a short-term (24 h) experiment. Markers of the initiation phase of lipid peroxidation, conjugated dienes, and trienes, were slightly affected by DON and OTA treatment at 16-h sampling. The termination marker, malondialdehyde, concentration increased only as an effect of FB₁. Glutathione content and glutathione peroxidase activity showed significantly higher levels in the T-2 and FB₁ groups at 8 h, and in the DON and FB₁ groups at 16 h. The expression of glutathione peroxidase genes (gpx4a, gpx4b) showed a dual response. Downregulation of gpxa was observed at 8 h, as the effect of DON, FB₁, and OTA, but an upregulation in the T-2 group. At 16 h gpx4a upregulated as an effect of DON, T-2, and FB_1, and at 24 h in the DON and T-2 groups. Expression of gpx4b downregulated at 8 h, except in the T-2 group, and upregulation observed as an effect of T-2 at 24 h. The lack of an increase in the expression of nrf2, except as the effect of DON at 8 h, and a decrease in the keap1 expression suggests that the antioxidant defence system was activated at gene and protein levels through Keap1-Nrf2 independent pathways.

Occurrence and transfer of mycotoxins from ingredients to fish feed and fish meat of common carp (Cyprinus carpio) in Serbia

As fish has been known for its high protein content and other health benefits, aquaculture production has started to flourish in Serbia. Common carp is the predominant species being farmed, comprising more than 80% of the total fish production in Serbia. The primary ingredients in fish feed are plant-based products, which present a risk of mycotoxin contamination, posing a potential risk to consumers. Therefore, this study aimed to determine the mycotoxin status of carp aquaculture in Serbia. At the beginning of the feeding season, May to June 2019, 27 samples of feed ingredients, 8 of finished feed and 14 of edible fish meat were analysed. The fish feed and feed ingredients were sampled from local producers, while the fish were sampled from fish farms that were reported to use the sampled feed. The feed ingredients were locally produced maize and maize products, sunflower meal, soybean and soybean products, wheat, bone meal, yeast and distillers dried grains with solubles, which were ground together, mixed and pelleted in different sizes. All samples were tested for the presence of aflatoxins (aflatoxin B1 (AFB1), B2, G1 and G2), ochratoxin A (OTA), zearalenone, deoxynivalenol, fumonisins (fumonisin B1 and B2), HT-2 and T-2 toxins. The most prevalent mycotoxins were OTA (91.4%), fumonisin B1+B2 (68.6%) and AFB1 (48.6%). Only one sample of the plant-based ingredients was below limit of quantification (LOQ), and more than 85% of the samples had more than one mycotoxin detected, ranging from 0.43 μg/kg of AFB1 to 3,168.5 μg/kg of fumonisin B1+B2. However, all the samples of edible fish meat were under the LOQ. We suggest that further research should be conducted on the effects of co-occurring mycotoxins; we also recommend stricter regulations on fish feed to reduce the impacts of mycotoxins on fish health and productivity.

Dietary ochratoxin A (OTA) decreases growth performance and impairs muscle antioxidant system and meat fatty acid profiles in juvenile tambaqui (Colossoma macropomum)

Plant-based ingredients are successfully replacing fishmeal in fish feeds. However, this practice increases the risk of feed contamination by mycotoxins that reduce production and heath associated with oxidative damage. The aim of this study was to determine whether feed contaminated with environmentally relevant concentrations of ochratoxin A (OTA) causes muscle oxidative damage in tambaqui (Colossoma macropomum), and to determine whether this feed impairs fatty acid profiles in fish meat. Final mean weight, weight gain, daily weight gain, feed efficiency, and specific growth rate were significantly lower in fish fed 1.6 and 2.4 mg OTA/kg compared to those fed basal diet, while feed conversion was significantly higher in these same groups compared to the basal group. Levels of reactive oxygen species and lipid peroxidation in muscle were significantly higher in fish fed 1.6 and 2.4 mg OTA/kg compared to those in the basal group. Likewise, muscle superoxide dismutase and glutathione peroxidase activities were significantly higher in fish fed 1.6 and 2.4 mg OTA/kg then in those fed basal feed. The total content of saturated fatty acids was significantly higher, and total content of polyunsaturated fatty acids was significantly lower in fish fed 2.4 mg OTA/kg compared to those fed basal feed. Taken together, the data suggest that OTA-contaminated feed induces oxidative damage and disturbs enzymatic and non-enzymatic antioxidant responses in tambaqui meat. The perturbations of fatty acid profiles in fish meat appears to mediated by oxidative damage, representing negative impact on fish health and presenting concerns for consumers of fish.

Effects of trichothecene mycotoxin T-2 toxin on haematological and immunological parameters of rainbow trout (Oncorhynchus mykiss)

The aim of this study was to assess the effects of T-2 toxin-contaminated feed (at concentrations of 1.0 and 1.8 mg/kg) on the rainbow trout immune system by studying non-specific cellular and humoral immune responses and its effect on red and white blood cells. Consumption of T-2 toxin at both concentrations resulted in significantly increased erythrocyte counts and a decrease in mean corpuscular volume. While a significant decrease in mean corpuscular haemoglobin was observed at both experimental concentrations, the decrease in plasma haemoglobin was only significant at the higher T-2 toxin concentration. Higher T-2 toxin concentrations resulted in a significant increase in leukocyte and lymphocyte count, while absolute phagocyte count and counts of less mature neutrophil granulocyte forms remained unchanged at both concentrations. Non-specific humoral immunity (bactericidal activity measured as complement activation) decreased significantly in both experimental groups when compared with the control. The results of this study show that T-2 toxin in feed at a concentration range of 1.0-1.8 mg/kg influences the immunological defence mechanisms of rainbow trout.Trial registration number, MSMT-3876/2014-14; date of registration, 31/1/2014.

Could mycotoxigenic Fusarium sp. play a role in ulcerative dermal necrosis (UDN) of brown trout (Salmo trutta morpha trutta)?

Fusarium infections have been reported in aquatic animals, but are still poorly investigated in wild salmonids. The aim of the study was to determine the impact of the fungi and their toxins on the health status of brown trout (Salmo trutta morpha trutta) migrating from the Baltic Sea to the freshwater. Individuals from the wild brown trout population exhibiting ulcerative skin lesions were collected from the Słupia River in Poland and subjected to microbiological, histopathological, and hematological examinations, as well as toxicological analysis for a presence of mycotoxins. The results of microflora isolation from the brown trout skin samples revealed the presence of conditionally pathogenic bacteria and fungi classified by molecular techniques as Fusarium spp. Toxicological analysis allowed for detection of zearalenone (ZEN) in the liver, kidney, and gastrointestinal tract of the fish. In several cases, there was α-zearalenone (α-ZEL) identified at trace levels in the liver, as well as sterigmatocystin and enniatin B at low levels in the kidney and the liver. Histopathological examination revealed the presence of fungal hyphae disrupting the epidermis and penetrating into the necrotic dermis and hypodermis. The decreased values of the blood parameters, i.e., hemoglobin concentration (HGB), packed cell volume (PCV), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and white blood cell count (WBC), were indicative of osmoregulation failure being a consequence of the skin damage. The results of the study provide new information regarding Fusarium sp. infection in brown trout and serve as the basis for further research on the potential impact of the fungi and their mycotoxins on the Baltic salmonid population, including their role in ulcerative dermal necrosis.

Combined effects of aflatoxin B1 and deoxynivalenol on the expression of glutathione redox system regulatory genes in common carp

The purpose of the present study was to evaluate the short-term effects of aflatoxin B₁ (AFB₁ ) and deoxynivalenol (DON) exposure on the expression of the genes encoding the glutathione redox system glutathione peroxidase 4a (gpx4a), glutathione peroxidase 4b (gpx4b), glutathione synthetase (gss) and glutathione reductase (gsr) and the oxidative stress response-related transcription factors Kelch-like ECH-associated protein 1 (keap1) and nuclear factor-erythroid 2 p45-related factor 2 (nrf2) in liver, kidney and spleen of common carp. During the 24-hr long experiment, three different doses (5 µg AFB₁ and 110 µg DON; 7.5 µg AFB₁ and 165 µg DON or 10 µg AFB₁ and 220 µg DON/kg bw) were used. The results indicated that the co-exposure of AFB₁ and DON initiated free radical formation in liver, kidney and spleen, which was suggested by the increase in Nrf2 dependent genes, namely gpx4a, gpx4b, gss and gsr. Expression of keap1 gene showed upregulation after 8 hr of mycotoxin exposure, and also upregulation of nrf2 gene was found in kidney after 8 hr of exposure, while in the liver, only slight differences were observed. The changes in the expression of the analysed genes suggest that level of reactive oxygen species reached a critical level where other signalling pathway was activated as described by the hierarchical model of oxidative stress.

Occurrence of Fungi and Fungal Toxins in Fish Feed During Storage

Periods of unfavorable storing conditions can lead to changes in the quality of fish feeds, as well as the development of relevant mycotoxins. In the present study, a commercial fish feed was stored under defined conditions for four weeks. The main findings indicate that even storing fish feeds under unsuitable conditions for a short duration leads to a deterioration in quality. Mycotoxin and fungal contamination were subsequently analyzed. These investigations confirmed that different storage conditions can influence the presence of fungi and mycotoxins on fish feed. Notably, ochratoxin A (OTA) was found in samples after warm (25 °C) and humid (>60% relative humidity) treatment. This confirms the importance of this compound as a typical contaminant of fish feed and reveals how fast this mycotoxin can be formed in fish feed during storage.