Effect of pH on the toxicity of fumonisins towards the RTL-W1 cell line and zebrafish (Danio rerio) embryos

Zebrafish as model organisms for toxicological evaluations in the field of food science

Food safety has long been an area of concern. The selection of stable and efficient model organisms is particularly important for food toxicology studies. Zebrafish (Danio rerio) are small model vertebrates, and 70% of human genes have at least one zebrafish ortholog. Zebrafish have advantages as model organisms due to their short life cycle, strong reproductive ability, easy rearing, and low cost. Zebrafish embryos have the advantage of being sensitive to the breeding environment and thus have been used as biosensors. Zebrafish and their embryos have been widely used for food toxicology assessments. This review provides a systematic and comprehensive summary of food toxicology studies using zebrafish as model organisms. First, we briefly introduce the multidimensional mechanisms and structure-activity relationship studies of food toxicological assessment. Second, we categorize these studies according to eight types of hazards in foods, including mycotoxins, pesticides, antibiotics, heavy metals, endocrine disruptors, food additives, nanoparticles, and other food-related ingredients. Finally, we list the applications of zebrafish in food toxicology studies in line with future research prospects, aiming to provide a valuable reference for researchers in the field of food science.

Interaction of Fumonisin B1, N-Palmitoyl-Fumonisin B1, 5-O-Palmitoyl-Fumonisin B1, and Fumonisin B4 Mycotoxins with Human Serum Albumin and Their Toxic Impacts on Zebrafish Embryos

Fumonisins are frequent food contaminants. The high exposure to fumonisins can cause harmful effects in humans and animals. Fumonisin B1 (FB1) is the most typical member of this group; however, the occurrence of several other derivatives has been reported. Acylated metabolites of FB1 have also been described as possible food contaminants, and the very limited data available suggest their significantly higher toxicity compared to FB1. Furthermore, the physicochemical and toxicokinetic properties (e.g., albumin binding) of acyl-FB1 derivatives may show large differences compared to the parent mycotoxin. Therefore, we tested the interactions of FB1, N-palmitoyl-FB1 (N-pal-FB1), 5-O-palmitoyl-FB1 (5-O-pal-FB1), and fumonisin B4 (FB4) with human serum albumin as well as the toxic effects of these mycotoxins on zebrafish embryos were examined. Based on our results, the most important observations and conclusions are the following: (1) FB1 and FB4 bind to albumin with low affinity, while palmitoyl-FB1 derivatives form highly stable complexes with the protein. (2) N-pal-FB1 and 5-O-pal-FB1 likely occupy more high-affinity binding sites on albumin. (3) Among the mycotoxins tested, N-pal-FB1 showed the most toxic effects on zebrafish, followed by 5-O-pal-FB1, FB4, and FB1. (4) Our study provides the first in vivo toxicity data regarding N-pal-FB1, 5-O-pal-FB1, and FB4.

The natural occurrence, toxicity mechanisms and management strategies of Fumonisin B1：A review

Fumonisin B1 (FB1) contaminates various crops, causing huge losses to agriculture and livestock worldwide. This review summarizes the occurrence regularity, toxicity, toxic mechanisms and management strategies of FB1. Specifically, FB1 contamination is particularly serious in developing countries, humid and hot regions. FB1 exposure can produce different toxic effects on the nervous system, respiratory system, digestive system and reproductive system. Furthermore, FB1 can also cause systemic immunotoxicity. The mechanism of toxic effects of FB1 is to interfere with the normal pathway of sphingolipid de novo biosynthesis by acting as a competitive inhibitor of ceramide synthase. Meanwhile, the toxic products of sphingolipid metabolic disorders can cause oxidative stress and apoptosis. FB1 also often causes feed contamination by mixing with other mycotoxins, and then exerts combined toxicity. For detection, lateral flow dipstick technology and enzyme linked immunosorbent assay are widely used in the detection of FB1 in commercial feeds, while mainstream detection methods such as high performance liquid chromatography and liquid chromatography-mass spectrometry are widely used in the laboratory theoretical study of FB1. For purification means of FB1, some natural plant extracts (such as Zingiber officinale and Litsea Cubeba essential oil) and their active compounds have been proved to inhibit the toxic effects of FB1 and protect livestock due to their antifungal and antioxidant effects. Natural plant extract has the advantages of high efficiency, low cost and no contamination residue. This review can provide information for comprehensive understanding of FB1, and provide reference for formulating reasonable treatment and management strategies in livestock production.

Occurrence, transformation, and toxicity of fumonisins and their covert products during food processing

Fumonisins comprise structurally related metabolites mainly produced by Fusarium verticillioides and Fusarium proliferatum. Contamination with fumonisins causes incalculable damage to the economy and poses a great risk to animal and human health. Fumonisins and their covert products are found in cereals and cereal products. Food processing significantly affects the degradation of toxins and the formation of covert toxins. However, studies on fumonisins and their covert mycotoxins remain inadequate. This review aims to summarize changes in fumonisins and the generation of covert fumonisins during processing. It also investigates the toxicity and determination methods of fumonisins and covert fumonisins, and elucidates the factors affecting fumonisins and their covert forms during processing. In addition to the metabolic production by plants and fungi, covert fumonisins are mainly produced by covalent or noncovalent binding, complexation, or physical entrapment of fumonisins with other substances. The toxicity of covert fumonisins is similar to that of free fumonisins and is a non-negligible hazard. Covert fumonisins are commonly found in food matrices, and methods to analyze them have yet to be improved. Food processing significantly affects the conversion of fumonisins to their covert toxins.

Variations of enzymatic activity and gene expression in zebrafish (Danio rerio) embryos co-exposed to zearalenone and fumonisin B1

The natural co-occurrence of multiple mycotoxins has been reported in cereals and cereal products worldwide. Even though the dietary exposure to mycotoxins constitutes a serious human health, most reports are limited to the toxic effect of individual mycotoxins. The purpose of the present study was to assess the combined toxic effects of zearalenone (ZEN) and fumonisin B1 (FB1) and the potential interaction of their mixture on zebrafish (Danio rerio) embryos. Our results showed that ZEN possessed the higher toxicity to embryonic zebrafish (7-day LC₅₀ value of 0.78 mg a.i. L^-1) compared with FB1 (7-day LC₅₀ value of 227.7 mg a.i. L^-1). The combination of ZEN and FB1 exerted an additive effect on zebrafish embryos. Meanwhile, the activities of antioxidant CAT, caspase-3, and detoxification enzyme CYP450, as well as the expressions of six genes (Mn-sod, cas9, bax, cc-chem, ERα, and crh) associated with oxidative stress, cellular apoptosis, immune system, and endocrine system were prominently altered in the mixture exposure compared with the corresponding single treatment group of ZEN or FB1. Taken together, the regulatory standards of mycotoxins in food and feed should be updated based on the mixture effects of mycotoxins, and there is an increased need on effective detoxification methods for controlling and reducing the toxicity of multiple mycotoxins in animal feed and throughout the food supply chain.

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.

Porous COS@SiO2 Nanocomposites Ameliorate Severe Acute Pancreatitis and Associated Lung Injury by Regulating the Nrf2 Signaling Pathway in Mice

Severe acute pancreatitis (SAP) is associated with high rates of mortality and morbidity. Chitosan oligosaccharides (COSs) are agents with antioxidant properties. We developed porous COS@SiO₂ nanocomposites to study the protective effects and mechanisms of COS nanomedicine for the treatment of acute pancreatitis. Porous COS@SiO₂ nanocomposites released COSs slowly under pH control, enabling sustained release and maintaining the drug at a higher concentration. This study aimed to determine whether porous COS@SiO₂ nanocomposites ameliorate SAP and associated lung injury. The SAP model was established in male C57BL/6 mice by intraperitoneal injection of caerulein. The expression levels of myeloperoxidase, malondialdehyde, superoxide dismutase, nuclear factor-kappa B (NF-κB), the NOD-like receptor protein 3 (NLRP3) inflammasome, nuclear factor E2-related factor 2 (Nrf2), and inflammatory cytokines were detected, and a histological analysis of mouse pancreatic and lung tissues was performed. In the SAP groups, systemic inflammation and oxidative stress occurred, and pathological damage to the pancreas and lung was obvious. Combined with porous COS@SiO₂ nanocomposites before treatment, the systemic inflammatory response was obviously reduced, as were oxidative stress indicators in targeted tissues. It was found that Nrf2 was significantly activated in the COS@SiO₂ treatment group, and the expressions of NF-κB and the NLRP3 inflammasome were notably decreased. In addition, this protective effect was significantly weakened when Nrf2 signaling was inhibited by ML385. This demonstrated that porous COS@SiO₂ nanocomposites activate the Nrf2 signaling pathway to inhibit oxidative stress and reduce the expression of NF-κB and the NLRP3 inflammasome and the release of inflammatory factors, thus blocking the systemic inflammatory response and ultimately ameliorating SAP and associated lung injury.