Zearalenone (ZEN) is a toxin produced by the Fusarium fungi, which is commonly found in grains.
While ZEN is already known for its harmful effects on reproduction due to its estrogen-like properties, this study highlights its damaging impact on the liver and intestines.
The paper also outlines the critical role gut bacteria and metabolites play in amplifying these effects.
“In laying hens, due to their long feeding cycle for optimal economic benefit, the risk of long-term ZEN exposure is much more significant than broiler chickens,” reported the authors.
However, current understanding of long-term ZEN toxicity on laying hens is limited, they noted.
With advancements in multiomic technologies, researchers have demonstrated that the negative effects of mycotoxin are mediated not only directly but also through altering gut microbiota and their metabolites.
But multiomic studies on ZEN toxicology are scarce, they added.
So they decided to conduct a 90-day study on 24 laying hens to assess the consequences of long-term exposure to ZEN at a dose of 2.0 mg/kg.
The findings paint a concerning picture of how ZEN compromises poultry health and, by extension, food safety.
Findings
The study showed that ZEN causes significant liver damage, including necrosis (cell death), inflammation, and elevated levels of markers linked to liver injury.
In the intestines, ZEN disrupted the structure of the lining, causing damage to the villi, while exposing deeper tissue layers.
ZEN also triggered changes in the gut microbiome. The hens exposed to ZEN had a more diverse microbial community but showed a shift in the balance of beneficial and harmful bacteria.
The researchers also saw a decrease in beneficial Lactobacillus and an increase in bacteria linked to inflammation.
These microbial changes coincided with altered metabolic activity in the gut.
The study found disruptions in amino acid processing, vitamin absorption, and stress-related pathways. Some specific metabolites were linked to increased liver damage, suggesting a direct connection between gut microbial activity and the toxic effects on the liver.
“We found that there was significant damage in the liver and different segments of the hens’ gut. The altered gut microbiota and the microbial-derived metabolites were found to have significant roles in ZEN toxicity.”
Limited impact on production
Even though the hens showed serious liver and intestinal damage, their body weight stayed the same.
This could mean that ZEN, a compound with estrogen-like effects, might have some unknown ability to promote growth, commented the team.
Some studies have found that ZEN consumption can lead to weight gain, which supports this idea. It’s possible that the growth-promoting effects of ZEN balanced out the digestive issues, keeping the hens’ weight stable, suggested the authors.
Egg production also wasn’t noticeably affected, despite lower estradiol levels and considerable damage to the oviduct tissue. A drop in egg production might take longer exposure to ZEN to show up, remarked the authors.
Previous studies suggest that how much ZEN hens consume and for how long can influence its effect on egg production.
The researchers stressed the importance of monitoring ZEN levels in poultry feed and taking steps to mitigate exposure to prevent adverse health outcomes in the birds.
Source: Poultry Science
