Altered Gene Response to Aflatoxin B1 in the Spleens of Susceptible and Resistant Turkeys

Efficacy of powdered alfalfa leaves to ameliorate the toxic effects of aflatoxin B1 in turkey poults

This experiment was conducted to determine the effect of an adsorbent material based on powdered alfalfa leaves added in the aflatoxin B1 (AFB1)-contaminated diet of turkey poults on production parameters, blood cell count, serum biochemistry, liver enzymes, and liver histology. For this purpose, three hundred and fifty female Nicholas-700 poults were randomly assigned into five treatments: (1) Control, AFB1-free diet; (2) AF, diet contaminated with 250 ng AFB1/g; (3) Alfalfa, AFB1-free diet + 0.5% (w/w) adsorbent; (4) AF+alfalfa, diet contaminated with 250 ng AFB1/g + 0.5% (w/w) adsorbent, and (5) AF+ yeast cell wall (YCW), diet contaminated with 250 ng AFB1/g + 0.5% (w/w) of yeast cell wall (a commercial mycotoxin binder used as reference material). The in vivo efficacy of powdered alfalfa leaves was assessed during a 28-day period. In general, the addition of powdered alfalfa leaves in the AFB1-free diet gave the best performance results (body weight, body weight gain, and feed intake) and improved the values of total protein, glucose, calcium, creatinine, and blood urea nitrogen. Moreover, the addition of powdered alfalfa leaves in the AFB1-contaminated diet enhanced body weight and body weight gain and significantly reduced the feed intake, compared to the AF and AF+YCW groups. Additionally, significant alterations in serum parameters were observed in poults intoxicated with the AFB1, compared to the Control group. Furthermore, typical histopathological lesions were observed in the liver of the AF group, which were significantly ameliorated with the addition of powdered alfalfa leaves. Conclusively, these results pointed out that low inclusion of powdered alfalfa leaves in the contaminated feed counteracted the adverse effects of AFB1 in turkey poults.

Genetic assessment of the effect of red yeast (Sporidiobolus pararoseus) as a feed additive on mycotoxin toxicity in laying hens

Toxic fungal species produce hazardous substances known as mycotoxins. Consumption of mycotoxin contaminated feed and food causes a variety of dangerous diseases and can even lead to death of animals and humans, raising global concerns for adverse health effects. To date, several strategies have been developed to counteract with mycotoxin contamination. Red yeast as a novel biological dietary agent is a promising strategy to eliminate mycotoxicity in living organisms. Poultry are most susceptible animals to mycotoxin contamination, as they are fed a mixture of grains and are at higher risk of co-exposure to multiple toxic fungal substances. Therefore, this study investigated the genetic mechanism underlying long-term feeding with red yeast supplementation in interaction with multiple mycotoxins using transcriptome profiling (RNA_Seq) in the liver of laying hens. The results showed a high number of significantly differentially expressed genes in liver of chicken fed with a diet contaminated with mycotoxins, whereas the number of Significantly expressed genes was considerably reduced when the diet was supplemented with red yeast. The expression of genes involved in the phase I (CYP1A1, CYP1A2) and phase II (GSTA2, GSTA3, MGST1) detoxification process was downregulated in animals fed with mycotoxins contaminated diet, indicating suppression of the detoxification mechanisms. However, genes involved in antioxidant defense (GSTO1), apoptosis process (DUSP8), and tumor suppressor (KIAA1324, FBXO47, NME6) were upregulated in mycotoxins-exposed animals, suggesting activation of the antioxidant defense in response to mycotoxicity. Similarly, none of the detoxification genes were upregulated in hens fed with red yeast supplemented diet. However, neither genes involved in antioxidant defense nor tumor suppressor genes were expressed in the animals exposed to the red yeast supplemented feed, suggesting decreases the adsorption of biologically active mycotoxins in the liver of laying hens. We conclude that red yeast can act as a mycotoxin binder to decrease the adsorption of mycotoxins in the liver of laying hens and can be used as an effective strategy in the poultry feed industry to eliminate the adverse effects of mycotoxins for animals and increase food safety for human consumers.

Integrated Transcriptome Analysis Reveals mRNA-miRNA Pathway Crosstalk in Roman Laying Hens' Immune Organs Induced by AFB1

Aflatoxin B1 (AFB1) is a widely distributed contaminant in moldy corn, rice, soybean, and oil crops. Many studies have revealed its adverse effects, such as carcinogenicity, immunotoxicity, and hepatotoxicity, on the health of humans and animals. To investigate the immunotoxic effects on chicken immune organs induced by AFB1, we integrated RNA and small-RNA sequencing data of the spleen and the bursa of Fabricius to elucidate the response of the differentially expressed transcriptional profiles and related pathways. AFB1 consumption negatively influenced egg quality, but no obvious organ damage was observed compared to that of the control group. We identified 3918 upregulated and 2415 downregulated genes in the spleen and 231 upregulated and 65 downregulated genes in the bursa of Fabricius. We confirmed that several core genes related to immune and metabolic pathways were activated by AFB1. Furthermore, 42 and 19 differentially expressed miRNAs were found in the spleen and the bursa of Fabricius, respectively. Differentially expressed genes and target genes of differentially expressed miRNAs were mainly associated with cancer progression and immune response. The predicted mRNA-miRNA pathway network illustrated the potential regulatory mechanisms. The present study identified the transcriptional profiles and revealed potential mRNA-miRNA pathway crosstalk. This genetic regulatory network will facilitate the understanding of the immunotoxicity mechanisms of chicken immune organs induced by high concentrations of AFB1.

The Mechanism Underlying the Extreme Sensitivity of Duck to Aflatoxin B1

Most metabolites of aflatoxin B1 (AFB1), especially exo-AFB1-8,9-epoxide (AFBO), can induce the production of reactive oxygen species (ROS) to vary degrees, causing oxidative stress and liver damage, and ultimately induce liver cancer in humans and animals. Duck is one of the most sensitive animals to AFB1, and severe economic losses are caused by duck AFB1 poisoning every year, but the exact mechanism of this high sensitivity is still unclear. This review highlights significant advances in our understanding of the AFB1 metabolic activation, like cytochrome P450s (CYPs), and AFB1 metabolic detoxification, like glutathione S-transferases (GSTs) in poultry. In addition, AFB1 may have other metabolic pathways in poultry, such as the mutual conversion of AFB1 and aflatoxicol (AFL) and the process of AFBO to produce AFB1-8,9-dihydrodiol (AFB1-dhd) and further metabolize it into detoxification substances. This review also summarized some exogenous regulatory substances that can alleviate AFB1-induced oxidative stress.

Insights into Aflatoxin B1 Toxicity in Cattle: An In Vitro Whole-Transcriptomic Approach

Aflatoxins, and particularly aflatoxin B1 (AFB1), are toxic mycotoxins to humans and farm animal species, resulting in acute and chronic toxicities. At present, AFB1 is still considered a global concern with negative impacts on health, the economy, and social life. In farm animals, exposure to AFB1-contaminated feed may cause several untoward effects, liver damage being one of the most devastating ones. In the present study, we assessed in vitro the transcriptional changes caused by AFB1 in a bovine fetal hepatocyte-derived cell line (BFH12). To boost the cellular response to AFB1, cells were pre-treated with the co-planar PCB 3,3′,4,4′,5-pentachlorobiphenyl (PCB126), a known aryl hydrocarbon receptor agonist. Three experimental groups were considered: cells exposed to the vehicle only, to PCB126, and to PCB126 and AFB1. A total of nine RNA-seq libraries (three replicates/group) were constructed and sequenced. The differential expression analysis showed that PCB126 induced only small transcriptional changes. On the contrary, AFB1 deeply affected the cell transcriptome, the majority of significant genes being associated with cancer, cellular damage and apoptosis, inflammation, bioactivation, and detoxification pathways. Investigating mRNA perturbations induced by AFB1 in cattle BFH12 cells will help us to better understand AFB1 toxicodynamics in this susceptible and economically important food-producing species.