Nutritional impact of mycotoxins in food animal production and strategies for mitigation

Mycotoxins are toxic secondary metabolites produced by filamentous fungi that are commonly detected as natural contaminants in agricultural commodities worldwide.Mycotoxin exposure can lead to mycotoxicosis in both animals and humans when found in animal feeds and food products,and at lower concentrations can affect animal performance by disrupting nutrient digestion,absorption,metabolism,and animal physiology.Thus,mycotoxin contamination of animal feeds represents a significant issue to the livestock industry and is a health threat to food animals.Since prevention of mycotoxin formation is difficult to undertake to avoid contamination,mitigation strategies are needed.This review explores how the mycotoxins aflatoxins,deoxynivalenol,zearalenone,fumonisins and ochratoxin A impose nutritional and metabolic effects on food animals and summarizes mitigation strategies to reduce the risk of mycotoxicity.

Traditional and emerging Fusarium mycotoxins disrupt homeostasis of bovine mammary cells by altering cell permeability and innate immune function

High incidence of traditional and emerging Fusarium mycotoxins in cereal grains and silages can be a potential threat to feed safety and ruminants.Inadequate biodegradation of Fusarium mycotoxins by rumen microflora following ingestion of mycotoxin-contaminated feeds can lead to their circulatory transport to target tissues such as mammary gland.The bovine udder plays a pivotal role in maintaining milk yield and composition,thus,human health.However,toxic effects of Fusarium mycotoxins on bovine mammary gland are rarely studied.In this study,the bovine mammary epithelial cell line was used as an in-vitro model of bovine mammary epithelium to investigate effects of deoxynivalenol(DON),enniatin B(ENB)and beauvericin(BEA)on bovine mammary gland homeostasis.Results indicated that exposure to DON,ENB and BEA for 48 h significantly decreased cell viability in a concentration-dependent manner(P<0.001).Exposure to DON at 0.39μmol/L and BEA at 2.5μmol/L for 48 h also decreased paracellular flux of FITC-40 kDa dextran(P<0.05),whereas none of the mycotoxins affected transepithelial electrical resistance after 48 h exposure.The qPCR was performed for assessment of expression of gene coding tight junction(TJ)proteins,toll-like receptor 4(TLR4)and cytokines after 4,24 and 48 h of exposure.DON,ENB and BEA significantly upregulated the TJ protein zonula occludens-1,whereas markedly downregulated claudin 3(P<0.05).Exposure to DON at 1.35μmol/L for 4 h significantly increased expression of occludin(P<0.01).DON,ENB and BEA significant downregulated TLR4(P<0.05).In contrast,ENB markedly increased expression of cytokines interleukin-6(IL-6)(P<0.001),tumor necrosis factorα(TNF-a)(P<0.05)and transforming growth factor-β(TGF-β)(P<0.01).BEA significantly upregulated IL-6(P<0.001)and TGF-β(P=0.01),but downregulated TNF-α(P<0.001).These results suggest that DON,ENB and BEA can disrupt mammary gland homeostasis by inducing cell death as well as altering its paracellular permeability and expression of genes involved in innate immune function.

Ovine hippocampal mRNA expression in offspring from dams supplemented with fishmeal and stress challenged in late pregnancy with endotoxin

Previous research has shown that adulthood disease can be attributed to stress events that occur during gestation. The objective of the present study was to determine whether maternal stress during late pregnancy, using a bacterial endotoxemia model, causes changes in hippocampal mRNA expression of candidate genes related to hypothalamic-pituitary-adrenal axis(HPAA) regulation in sheep. This study also sought to investigate whether maternal diets supplemented with fishmeal(FM) rich in omega-3 polyunsaturated fatty acids(PUFAs) offer protection to the fetus when subjected to maternal endotoxin stress. Using RT-qPCR, relative mRNA expression was assessed in both fetal lambs and 6-month-old lambs from dams supplemented with soybean meal(SM) or FM and challenged with either endotoxin or saline. From this it was found that fetal mineralocorticoid receptor(MR) gene expression had a tendency to be altered during endotoxin challenge, however, in the 6-month-old offspring, MR and glucocorticoid receptor(GR) gene expression were differently altered across treatment groups. These results suggest that gene regulation within the hippocampus is altered into adulthood by maternal endotoxin stress and that dietary supplementation affects outcome.