Effect of Sterigmatocystin or Aflatoxin Contaminated Feed on Lipid Peroxidation and Glutathione Redox System and Expression of Glutathione Redox System Regulatory Genes in Broiler Chicken.

Balogh Balogh,Inotai Inotai,Bata-Vidács Bata-Vidács,Kövesi Kövesi,Zándoki Zándoki,Mézes Mézes,Szekeres Szekeres,Ancsin Ancsin,Erdélyi Erdélyi,Kulcsár Kulcsár,Kukolya Kukolya,Dobolyi Dobolyi

doi:10.3390/antiox8070201

Abstract

Authors studied the effect of sterigmatocystin from infected corn (STC), purified sterigmatocystin (PSTC), and aflatoxin B1 from infected corn (AFB1) on lipid peroxidation and glutathione redox parameters, including the expression of their encoding genes in a sub-chronic (14 days) trial. A total of 144 three-week-old cockerels was divided into four experimental groups (n = 36 in each). Control feed was contaminated with STC or PSTC (1590 µg STC/kg or 1570.5 µg STC/kg feed), or with AFB1 (149.1 µg AFB1/kg feed). Six birds from each group were sampled at day 1, 2, 3, 7 and 14 of mycotoxin exposure. As parameters of lipid peroxidation, conjugated dienes (CD) and trienes (CT) were measured in the liver, while malondialdehyde (MDA) concentration was determined in blood plasma, red blood cell hemolysate and liver. Reduced glutathione (GSH) concentration and glutathione peroxidase (GPx) activity were determined in the same samples, and expression of glutathione peroxidase 4 (GPX4), glutathione synthetase (GSS) and glutathione reductase (GSR) genes was measured by RT-PCR in the liver. STC, PSTC or AFB1 caused a slight, but not significant, increase in CD and CT levels; however, in the case of MDA, no increase was found in the liver. Glutathione redox system was activated in the liver by AFB1, but less markedly by STC/PSTC. PSTC and AFB1 resulted in a higher expression of GPX4, while GSS expression was down-regulated by AFB1 on day 1, but up-regulated by STC on day 2 and by both mycotoxins on day 7. However, on day 14, GSS expression was down-regulated by PSTC. Expression of GSR was low on day 1 in AFB1 and PSTC groups, but later it was up-regulated by AFB1. The observed changes regarding gene expression strengthen the hypothesis that the mild oxidative stress, caused by the applied STC doses, activates the glutathione redox system of broiler chickens.

Highlights

Mycotoxins are secondary metabolites of filamentous fungi, and are toxic to animals and humans
At the age of 21 days, 144 of the chickens were randomly divided into four experimental groups
It caused some alterations in production parameters, had a rapid pro-oxidant effect and caused elevations in the initial, but not in the terminal phase parameters of lipid peroxidation processes in the liver, and in the amount and activity of the glutathione redox system

Summary

Introduction

Mycotoxins are secondary metabolites of filamentous fungi, and are toxic to animals and humans. Fungi of Aspergillus genus produce several mycotoxins. Antioxidants 2019, 8, 201 than ten types, the most toxic being AFB1 —are mainly produced by Aspergillus flavus and Aspergillus parasiticus. Sterigmatocystin (STC), which has a molecular structure similar to aflatoxins, and acts as an intermediate in the biosynthetic pathway of aflatoxins [1], is mostly produced by Aspergillus nidulans and Aspergillus versicolor [2]. Two main target organs of the STC-toxicity are kidneys and liver [4]. The pathological symptoms after STC-exposure are hepatocellular necrosis and hemorrhages in the liver and hyaline degeneration, hemorrhages and tubular necrosis in the kidneys

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