A recent study explored how different feed additives can reduce harmful toxins in dairy cows exposed to contaminated diets.
The work involved researchers from the University of Sao Paulo, the Federal University of Technology–Paraná, Brazil, and mycotoxin experts from DSM-Firmenich.
Animals consuming mycotoxin-contaminated feed can experience a range of symptoms, including digestive issues like diarrhea and soft stools, weakened immune function, and overall reduced performance, noted the authors of the study.
Their paper was published in the Journal of Dairy Science.
While the exact biological processes behind these effects are not yet fully understood, common signs include imbalances in rumen or gut microbiota, increased permeability of the gut or rumen lining, and damage to the gut epithelium, they reported.
In dairy cows, mycotoxins and their metabolites—or even unmetabolized compounds—can pass into milk, posing a potential risk of dietary exposure to humans, added the authors.
Among the strategies to manage mycotoxin-contaminated feed after harvest, using hydrated sodium calcium aluminosilicate (HSCA)—a clay-based agent—has proven effective in reducing the absorption of aflatoxins (AF) in the gut and their secretion into milk, according to the literature.
“However, these clay-based agents are less effective against other types of mycotoxins, such as Fusarium toxins, which can significantly impact animal performance,” commented the team.
To address these limitations, researchers have explored mycotoxin-deactivating products (MDP), which combine inorganic and biological components, enzymes, and phycophytic compounds, which are algae and plant derived.
The authors outlined how MDPs have shown positive effects on animal performance, immune function, and metabolism in cows exposed to various mycotoxins.
Despite these benefits, studies have not extensively examined the impact of MDP on mycotoxin excretion in milk, they added.
Their study aimed to evaluate the effects of different anti-mycotoxin feed additives on mycotoxin levels in the milk, urine, and blood plasma of dairy cows fed a multi-mycotoxin-contaminated diet for a brief period.
The team hypothesized that even short-term exposure to contaminated feed would reduce nutrient digestibility and overall cow performance.
They also proposed that adding MDP to the diet could mitigate these effects and reduce mycotoxin levels in milk, urine, and blood plasma.
The study
The study involved 12 dairy cows fed a diet intentionally contaminated with mycotoxins to mimic real-world challenges.
Four diets were evaluated: a basic contaminated diet without additives, a diet with a mineral additive (HSCA) included at a dosage level of 25g per cow per day, and two diets with different doses of a commercial mycotoxin deactivator (MD) - at 15g per cow per day (MD15), and at 30g per cow per day (MD30).
The researchers measured how well these experimental diets reduced toxin levels in the cows and whether they affected milk yield or nutrient absorption.
All cows in the study were fed a diet intentionally mixed with a combination of mycotoxins to simulate real-world contamination.
The mixture included tiny amounts of toxins added daily: 0.4 milligrams (mg) of aflatoxin B1, about 5 milligrams of deoxynivalenol (DON), 8 mg of fumonisins (FUM), 0.2mg of T2 toxin, and about 2mg of zearalenone (ZEN). These were added to the cows’ diets during the last seven days of each experimental period.
Key findings
- All additives significantly reduced the presence of aflatoxin M1 in the cows' milk. However, the MD diets were more effective than the mineral additive.
- Milk from cows receiving the MD additives contained no detectable levels of other common toxins, including DON and FUM.
- The MD additive also reduced toxins in urine and blood plasma more effectively than the mineral-based diet, especially at higher doses.
Conclusions
Using a mycotoxin deactivator during short-term exposure to contaminated feed effectively reduced levels of several harmful mycotoxins—AFM1, DON, FUM, T2, and ZEN—in the blood, milk, and urine of dairy cows at both tested doses, concluded the team.
The higher dose (MD30) achieved the greatest reduction, lowering most mycotoxins in blood, urine, and milk to undetectable levels, except for trace amounts of AFM1 in milk and urine, they saw.
The lower dose (MD15) also reduced all mycotoxins, while the clay-based additive (HSCA) showed only a small reduction in aflatoxin levels and was ineffective against other mycotoxins, reported the authors.
The study found no impact on the cows' performance or nutrient digestibility, but it highlighted that even short-term exposure to contaminated diets allows dairy cows to absorb and secrete mycotoxins into their milk, which can pose a risk for human health.
Source: Journal of Dairy Science