Evaluation of Inner Exposure of Horses to Zearalenone (ZEN), Deoxynivalenol (DON) and Their Metabolites in Relation to Colic and Health-Related Clinical-Chemical Traits

Abstract

Mycotoxin contaminated feed has been associated with colic of horses caused by intestinal disorders. Whether such disease conditions alter the intestinal toxin metabolism and transfer across a compromised mucosal barrier is unknown. A screening approach was used to relate blood residue levels of DON, ZEN and their metabolites to the status of the horses (sick vs. healthy). A total of 55 clinically healthy horses from 6 different farms with varying feeding background served as control for sick horses (N = 102) hospitalized due to colic. ZEN, alpha-zearalenol (ZEL), beta-ZEL and DON were detectable in peripheral blood as indicators for the inner exposure with significant farm effects for alpha- and beta-ZEL. However, the levels in sick horses were similar to all farms. Moreover, the proportion of beta-ZEL of all detected ZEN metabolites as an indicator for the degree of metabolism of ZEN was not different for sick horses but differed amongst the control farms. Although the incidence of DON in blood was generally low and not significantly different amongst healthy and sick horses, the positive samples were nearly exclusively found in sick horses suggesting either a higher toxin transfer, an association of DON with the development of colic or a different feeding background.

Investigation of forage mycotoxin levels in horses with increased liver enzyme concentrations

“…The lack of a control group was a significant limitation of the study. Previous studies identifying mycotoxin exposure of horses with colic and liver disease, also identified mycotoxins in control populations (Dänicke et al 2021;Durham 2022). Whilst we cannot conclude in this study if the increased liver enzyme concentrations were related to the mycotoxin exposure, it has demonstrated the frequency at which mycotoxins are identified in UK forage.…”

“…Feed refusal and gastrointestinal erosions have been noted in pigs after chronic exposure to deoxynivalenol (DON), which is a type of Type B trichothecenes (Pinton and Oswald, 2014). DON was found more commonly in colic cases compared to the control group in one study (Dänicke et al 2021). In a study by Raymon et.…”

“…Durham, 2022, found that fumonisin B1 may be associated with outbreaks of liver disease (Durham 2022). However, studies have also found mycotoxins in a high proportion of forage fed to the control groups (Dänicke et al 2021;Durham 2022). Our understanding of what mycotoxins horses are exposed to in forage is limited and even less is published regarding which mycotoxins could be clinically significant in horses.…”