Oxidative stress mediated the inhibition of cerebral creatine kinase activity in silver catfish fed with aflatoxin B1-contaminated diet

Metal Toxicity: Effects on Energy Metabolism in Fish

Metals are dispersed in natural environments, particularly in the aquatic environment, and accumulate, causing adverse effects on aquatic life. Moreover, chronic polymetallic water pollution is a common problem, and the biological effects of exposure to complex mixtures of metals are the most difficult to interpret. In this review, metal toxicity is examined with a focus on its impact on energy metabolism. Mechanisms regulating adenosine triphosphate (ATP) production and reactive oxygen species (ROS) emission are considered in their dual roles in the development of cytotoxicity and cytoprotection, and mitochondria may become target organelles of metal toxicity when the transmembrane potential is reduced below its phosphorylation level. One of the main consequences of metal toxicity is additional energy costs, and the metabolic load can lead to the disruption of oxidative metabolism and enhanced anaerobiosis.

Physiological strategies of acute thermal conditions of Rhamdia voulezi collected in the Iguaçu river watershed, Paraná, Brazil: biochemical markers of metabolic and oxidative stress

Thermal pollution creates substantial challenges that alter energy demand and produce reactive oxygen species that damage fish DNA, proteins, and lipids. Rhamdia voulezi is a species of fish native to the Iguaçu river, Paraná, Brazil, that does not have scientific records of minimum (CTmin) and maximum (CTmax) temperatures required for survival. As it is a top predator species in the food chain and lives at temperatures below 22 °C, the loss of the species can cause functional problems in controlling the ecosystem and energy flow. The study evaluated the tissue metabolism of the brain, heart, and muscle of R. voulezi (n = 72) subjected to acute thermal stress of 31 °C for 2, 6, 12, 24, and 96 h after acclimatization to 21 °C. The biochemical markers SOD, GPx, MDH, HK, and CK of the brain, PCO of the heart and CAT, glycogen, G6PDH, and ALT of muscle were significant. PCA, IBR, thermal sensitive, and condition factor suggested that R. voulezi has different physiological strategies for acclimatization to 31 °C to mobilize and sustain the metabolic needs of oxygenation and energy allocation/utilization for tissue ATP production.

Aflatoxin B1 induces infertility, fetal deformities, and potential therapies

Aflatoxin B1 (AFB1) is a subsidiary poisonous metabolite, archetypally spawned by Aspergillus flavus and A. parasiticus, which are often isolated in warm or tropical countries across the world. AFB1 is capable of disrupting the functioning of several reproductive endocrine glands by interrupting the enzymes and their substrates that are liable for the synthesis of various hormones in both males and females. In men, AFB1 is capable of hindering testicular development, testicular degeneration, and reduces reproductive capabilities. In women, a direct antagonistic interaction of AFB1 with steroid hormone receptors influencing gonadal hormone production of estrogen and progesterone was responsible for AFB1-associated infertility. AFB1 is potentially teratogenic and is responsible for the development of malformation in humans and animals. Soft-tissue anomalies such as internal hydrocephalus, microphthalmia, cardiac defects, augmented liver lobes, reproductive changes, immune modifications, behavioral changes and predisposition of animals and humans to neoplasm development are AFB1-associated anomalies. Substances such as esculin, selenium, gynandra extract, vitamins C and E, oltipraz, and CDDO-Im are potential therapies for AFB1. Thus, this review elucidates the pivotal pathogenic roles of AFB1 in infertility, fetal deformities, and potential therapies because AFB1 toxicity is a key problem globally.

Aluminum-maltol induced oxidative stress and reduced AMPK activity via BCK-related energy supply failure in C6 cell

Aluminum (Al) exposure significantly interferes with the energy supply in astrocytes, which may be a potential mechanism of Al-induced neurotoxicity. This study was designed to explore the mechanisms of Al-induced energy supply impairment in rat C6 astroglioma cell line. Aluminum-maltolate (Al(mal)3) (0.1 mM, 24 h) exposure significantly decreased brain-type creatine kinase (BCK) co-localization with the endoplasmic reticulum (ER) and resulted in mitochondrial dysfunctions, accompanied by a decrease in AMPK phosphorylation. The results of molecular docking showed that Al(mal)3 increased BCK's hydrophobicity and hindered the localization movement of BCK between subcells·H2O2 co-administration was found to exacerbate mitochondrial dysfunction, Ca2+ dyshomeostasis, and apoptosis. After treated with Al(mal)3, additional oxidative stress contributed to BCK activity inhibition but did not promote a further decrease in AMPK phosphorylation. The activation of p-AMPK by its agonist can partially restore mitochondrial function, BCK activity, and ER-localized-BCK levels in Al(mal)3-treated astrocytes. In summary, Al exposure resulted in a sustained depletion of the mitochondrial and antioxidant systems, which was associated with reduced p-AMPK activity and decreased ER-localized-BCK levels in astrocytes. This study provides a theoretical basis for exploring the mechanisms of neurotoxicity induced by Al exposure.

Hesperetin protects hippocampal neurons from the neurotoxicity of Aflatoxin B1 in mice

Aflatoxin B1 (AFB1) is a major food and feed pollutant that endangers public health. Previous studies have shown that exposure to AFB1 causes neurotoxicity in the body. However, the mechanism of neurotoxicity caused by AFB1 is not well understood, and finding a workable and practical method to safeguard animals from AFB1 toxicity is essential. This study confirmed that AFB1 caused endoplasmic reticulum stress (ER stress) and apoptosis in hippocampal neurons using C57BL/6 J mice and HT22 cells as models. In vitro experiments showed that the aryl hydrocarbon receptor (AHR) plays a significant role in the cytotoxicity of AFB1. Finally, we assessed how hesperetin protecting against the neurotoxicity caused by AFB1. Our findings demonstrated that AFB1 increased the levels of BAX and Cleaved-Caspase3 proteins, while decreasing the levels of BCL2 protein in the CA1 and CA3 regions of the hippocampus. The AFB1 increased the expression of AHR and activated nuclear translocation. It also elevated the expression levels of Chop, GRP78, p-IRE1/ Xbp1s, and p-PERK/p-EIF2a. Importantly, we also discovered for the first time that blocking AHR in HT22 cells dramatically reduced the level of ER stress and apoptosis caused by AFB1. In vivo and in vitro studies, supplementation of hesperetin effectively reversed AFB1-induced cytotoxicity. We have demonstrated that hesperetin effectively restored the imbalance in the GSH/GST system in HT22 cells treated with AFB1. Furthermore, we observed that elevated GSH levels facilitated the formation of AFB1-GSH complexes, which enhanced the excretion of AFB1. Therefore, hesperetin improves ER stress-induced apoptosis by reducing AFB1 activation of AHR.

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.

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.

May phytophenolics alleviate aflatoxins-induced health challenges? A holistic insight on current landscape and future prospects

The future GCC-connected environmental risk factors expedited the progression of nCDs. Indeed, the emergence of AFs is becoming a global food security concern. AFs are lethal carcinogenic mycotoxins, causing damage to the liver, kidney, and gastrointestinal organs. Long-term exposure to AFs leads to liver cancer. Almost a variety of food commodities, crops, spices, herbaceous materials, nuts, and processed foods can be contaminated with AFs. In this regard, the primary sections of this review aim to cover influencing factors in the occurrence of AFs, the role of AFs in progression of nCDs, links between GCC/nCDs and exposure to AFs, frequency of AFs-based academic investigations, and world distribution of AFs. Next, the current trends in the application of PPs to alleviate AFs toxicity are discussed. Nearly, more than 20,000 published records indexed in scientific databases have been screened to find recent trends on AFs and application of PPs in AFs therapy. Accordingly, shifts in world climate, improper infrastructures for production/storage of food commodities, inconsistency of global polices on AFs permissible concentration in food/feed, and lack of the public awareness are accounting for a considerable proportion of AFs damages. AFs exhibited their toxic effects by triggering the progression of inflammation and oxidative/nitrosative stress, in turn, leading to the onset of nCDs. PPs could decrease AFs-associated oxidative stress, genotoxic, mutagenic, and carcinogenic effects by improving cellular antioxidant balance, regulation of signaling pathways, alleviating inflammatory responses, and modification of gene expression profile in a dose/time-reliant fashion. The administration of PPs alone displayed lower biological properties compared to co-treatment of these metabolites with AFs. This issue might highlight the therapeutic application of PPs than their preventative content. Flavonoids such as quercetin and oxidized tea phenolics, curcumin and resveratrol were the most studied anti-AFs PPs. Our literature review clearly disclosed that considering PPs in antioxidant therapies to alleviate complications of AFs requires improvement in their bioavailability, pharmacokinetics, tissue clearance, and off-target mode of action. Due to the emergencies in the elimination of AFs in food/feedstuffs, further large-scale clinical assessment of PPs to decrease the consequences of AFs is highly required.

Metabolite profiling of the post-ovulatory oocytes of the common carp, Cyprinus carpio: A 1H NMR-based metabolomics approach

A metabolomics study was conducted to investigate the molecular bases of oocyte over-ripening in common carp, Cyprinus carpio from a metabolic point of view. The ovulation was induced in fish brooders by intramuscular injection of pituitary extract and oocytes were collected four times post-ovulation with 30 min intervals. A set of 32 metabolites were identified on the NMR spectra of the oocytes, which mainly included energy-linked metabolites, amino acids, methylated metabolites and citric acid cycle (TCA) intermediates. PCA and PLS-DA models clearly separated the post ovulations times, indicating the effects of post-ovulation time on oocyte metabolome content. Based on the loading plot outputs, 15 metabolites including tryptophan, cysteine, AMP, tyrosine, valine, creatine phosphate (PCr), ATP, leucine, inosine, malate, acetate, TMAO, glucose, fumarate and lysine had more effects on the separation of post ovulation times. According to the results of metabolite profiling, the concentrations of glutamine, alanine, tryptophan, lysine and cysteine mostly significantly (P < 0.01) increased at 90 and 120 min post-ovulation. The concentrations of PCr, ATP, inosine and guanosine were relatively stable until 60 min post-ovulation, while significantly (P < 0.01) decreased at 90 and 120 min post ovulation. The TCA metabolites succinate, malate and fumarate significantly (P < 0.01) elevated at 90 and 120 min post-ovulation. AMP concentrations remained relatively unchanged until 30 min and then progressively decreased with time post ovulation (P < 0.01). The concentrations of lactate showed significant elevations at 90 and 120 min post ovulation (P < 0.01). In conclusion, the energetic potentials of the oocytes reduced with time post ovulation. There were apparent elevations in the concentrations of free amino acids, which may be associated with the onset of proteolytic activities in the post ovulatory oocytes. In addition, we found some changes in the apoptotic-related metabolites, which may support the results of previous studies regarding the oxidative stress and following apoptosis in post ovulatory oocytes of fish.

The role of mycotoxins in neurodegenerative diseases: current state of the art and future perspectives of research

Mycotoxins are fungal metabolites that can cause various diseases in humans and animals. The adverse health effects of mycotoxins such as liver failure, immune deficiency, and cancer are well-described. However, growing evidence suggests an additional link between these fungal metabolites and neurodegenerative diseases. Despite the wealth of these initial reports, reliable conclusions are still constrained by limited access to human patients and availability of suitable cell or animal model systems. This review summarizes knowledge on mycotoxins associated with neurodegenerative diseases and the assumed underlying pathophysiological mechanisms. The limitations of the common in vivo and in vitro experiments to identify the role of mycotoxins in neurotoxicity and thereby in neurodegenerative diseases are elucidated and possible future perspectives to further evolve this research field are presented.

Fumonisin-(Fusarium verticillioides)-contaminated feed causes hepatic oxidative stress and negatively affects broiler performance in the early stage: Does supplementation with açai flour residues (Euterpe oleracea) minimize these problems?

Fusarium verticillioides is often responsible for contamination of poultry feed with the mycotoxin fumonisin. The aim of this study was to determine whether oxidative stress caused by intake of fumonisin-contaminated feed affects broiler performance at an early stage of development, as well as to test whether the addition of açai residue flour to contaminated feed would minimize these negative effects of redox metabolism. Birds were divided into four groups, with four repetitions of five animals each: control (TC) - birds that received basal feed; TCA treatment - basal feed supplemented with 2% açai flour; TF treatment - feed experimentally contaminated with fumonisin (10 ppm); TFA treatment - fumonisin-contaminated feed (10 ppm) and supplemented with açai fluor (2%). The experiment lasted 20 days, that is, the first 20 days of the chicks' lives. At the end of the experiment, the birds were weighed, and blood, intestine and liver samples were collected. The TCA and TFA had greater body weights and weight gain than did TF. Further, TCA and TFA had lower feed conversion than did TF. Açai flour intake (TCA and TFA) stimulated albumin synthesis and reduced serum AST activity. Nitrate/nitrite (NOx) levels were higher in serum of fumonisin-challenged (TF) birds than in groups; NOx levels were also higher in the livers of all test groups (TF, TCA and TFA) than in TC. Serum glutathione S-transferase (GST) activity was lower in fumonisin-consuming groups (TF and TFA); this was different from what occurred in the liver, that is, higher GST activity in TF and lower activity in TFA than in TC. Catalase activity (CAT) was also higher in the fumonisin-challenged groups (TF and TFA) and the groups supplemented with açai flour (TCA) than in TC. Serum reactive species (RS) and TBARS (lipid peroxidation) levels in the liver were lower in birds supplemented with açai flour and exposed to fumonisin. These data suggest that the addition of açai flour in the feed of early chickens improves animal performance and minimizes the effects of hepatic oxidative stress in birds fed fumonisin-contaminated feed.