# Fungal Contamination of Dairy Feed and Major Mycotoxin Transfer: A Risk Evaluation for Animal Exposure and Health

## TL;DR

This study evaluates fungal contamination and mycotoxin transfer in dairy feed, assessing risks to animal health and biochemical responses in cattle.

## Contribution

The study reveals moisture-driven fungal dynamics and metabolic effects of low-dose aflatoxin exposure in dairy cattle.

## Key findings

- High moisture promotes co-proliferation of fungi like Fusarium, while dry substrates favor Aspergillus.
- Mycotoxin levels, especially OTA and ZEA, fluctuate dynamically during feed storage.
- AFM1 in milk remains low, but aflatoxin exposure causes detectable metabolic changes in cattle.

## Abstract

This study was focused on the assessment of fungal occurrence, mycotoxin dynamics, aflatoxin carry-over, and associated biochemical responses in dairy cattle. Moisture emerged as the dominant factor for fungal communities, promoting the co-proliferation of fungal genera adapted to high water activity conditions (aw > 0.90) and antagonism against xerotolerant and xerophilic species. Aspergillus spp. dominated dry substrates (aw < 0.75), Fusarium spp. showed strong positive associations with high-moisture matrices (aw > 0.90), and Penicillium spp. exhibited intermediate, substrate-dependent behavior. Mycotoxin levels fluctuated non-linearly, independently of fungal counts: ochratoxin A (OTA) concentrations in corn silage increased from approximately 12 μg/kg at the onset of the ensiling period to >240 μg/kg at silo opening, indicating dynamic mycotoxin accumulation during storage, while zearalenone (ZEA) oscillated from 40 to 170 µg/kg. Despite the variation in total aflatoxins (AFLA-T) across feed matrices, aflatoxin M1 (AFM1) in milk remained low (0.0020–0.0093 μg/kg), confirming limited carry-over. Serum biochemical parameters—alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), total bilirubin (BIL-T), total protein (PROT-T)—remained within physiological limits, yet multivariate analyses revealed metabolic modulation linked to aflatoxin exposure. AFM1 explained >7% of the variance in serum biochemical profiles according to PERMANOVA (p = 0.002), showed significant MANOVA effect (Pillai = 0.198), and displayed a significant canonical association (p < 10−13). Linear discriminant analysis further separated Normal vs. Borderline hepatic profiles, indicating subclinical physiological adaptation to chronic low-dose exposure.