The importance of oxidative stress in laying hen longevity
As laying cycles continue to lengthen, supporting hens through the metabolic demands of sustained egg production has become increasingly important.
Tight supply coupled with high demand has been welcomed in the recent egg market. However, the drive to improve sustainability and maximise return on investment has encouraged many egg producers to extend the productive lifespan of their flocks.
Commercial laying flocks in the UK and Ireland are traditionally depleted at 75-80 weeks, dictated largely by a reduction in egg production and deterioration of shell quality. However, improvements in nutrition and genetics, especially in white breeds, now mean many flocks remain productive for 90 or even 100 weeks.
But maintaining high egg production over a longer period places considerable metabolic demands on the hen.
"Although extending lay can significantly improve profitability, hens are under increasing physiological pressure as production continues," explains Georgina Phillips, poultry specialist at Phileo UK & Ireland.
"The decline we often see in egg production and shell quality isn't simply a consequence of age. Oxidative stress is a silent but destructive process that accelerates cellular damage, indirectly impacts production and makes the bird more vulnerable to disease."
Fortunately, selenium is well-researched and recognised as a powerful nutritional tool to help combat oxidative stress. This essential trace element functions as a cofactor for antioxidant enzymes, namely glutathione peroxidase (GPx).
Therefore, a consistent dietary supply of selenium is essential for protecting cells from oxidative damage.
Selenium supplementation in poultry diets is carefully regulated to ensure birds receive enough of this micronutrient without risking toxicity.
The form of selenium also influences how effectively it can be utilised by the bird. Organic selenium sources are preferred due to higher trace element bioavailability that supports better retention in body muscle and eggs.
“Selenium-enriched yeasts like Selsaf® are a natural source of organic selenium with higher uptake proven in laying hens,” Georgina continues. “Inorganic selenium is absorbed via passive diffusion, however the seleno-compounds in Selsaf are actively transported through the intestinal wall, ensuring maximum utilization by the bird.”
This allows hens to cope better with the demands of egg production, by allowing them to invest more energy and resources into immunity, defence against disease and performance.
Seleno-compounds include both selenocysteine and selenomethionine. Selenocysteine forms part of GPx, while selenomethionine is stored in muscle tissue, providing a reserve that can be utilized during periods of increased demand.
“By making them more resilient to oxidative stress, we have seen layers have improved survival rates and laying intensity when supplemented with Selsaf. This particularly helpful during stressful conditions such as longer production cycles or periods of hot weather,” she adds.
In addition to supporting the bird, selenium enrichment of eggs offers further benefits. Selenomethionine is stored in eggs, where it limits lipid oxidation for improved freshness and shelf life of eggs.
Higher selenium concentration in eggs can also help producers tap into a growing market for functional, health-driven produce. Selenium-enriched eggs offer consumers a simple way to boost antioxidants in their diet, supporting human health and well-being as well as in poultry.
“Oxidative stress is an unavoidable challenge in modern poultry production, but its impact on bird health and egg quality can be managed,” concludes Georgina.
“Organic selenium stands out as a powerful antioxidant to help maintain immune function and egg production well into the later weeks of lay. As the industry moves toward longer laying cycles and more sustainable production, selenium supplements like Selsaf will play an important role in ensuring healthy, high-performing hens that deliver consistent, high-quality eggs, benefiting producers and consumers alike.”
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