Selisseo® is a unique, pure and reliable organic form of selenium that helps animals fight oxidative stress.
Selisseo® contains 100% hydroxy-selenomethionine (OH-SeMet), a pure and highly available form of organic selenium that helps animals combat oxidative stress. Selenium (Se) is an essential nutrient for life and it has been established that 0.1-0.3 ppm is necessary to support basic functions. While inorganic Se sources such as sodium selenite are commonly used as feed supplements, recent research has confirmed that organic Se sources, and in particular selenomethionine (SeMet) and OH-SeMet are absorbed more efficiently.
What really makes Selisseo® stand out is its ability to help animals cope better with stress by storing more SeMet in their tissues. This key feature boosts stress resistance to maintain the growth performance under challenging conditions.
Elevate end-product quality with Selisseo®. Your assurance of premium quality meat, eggs and milk.
Selisseo® enhances reproductive performance, towards healthier offspring and sustained breeding success.
The purpose of organic Selenium (Se) is to provide Se in the form of selenomethionine (SeMet) as this is the only form of Se that can both be utilized for selenoprotein production and safely stored in the animal body to build up Se reserves. Animals can utilize its Se reserves during times of increased oxidative stress, when the need for Se is higher. These Se reserves are key to maximizing all the benefits of Se.
However, only 63% of the Seleno-Yeast of Se is in the form of SeMet and this percentage can be quite variable.
On the other hand, Selisseo® provides 100% of Se as OH-SeMet, thus ensuring an optimal Se reserve and supporting the performance of animals.

Selisseo® is the only hydroxy-selenomethionine on the market, fully delivering the benefits of organic selenium for enhanced stress resistance and immunity, optimal growth, better reproduction performance and higher quality of end-products.
In this video, Pierre-André Geraert explains the genesis of Selisseo®, a pure form of organic selenium. What led Adisseo to work on antioxidants? Why hydroxy-selenomethionine? To obtain answers to these questions, listen to the explanations of Pierre-André!
In this video, Michele De Marco describes the origin of oxidative stress in livestock farming and its lipid peroxidation, protein and DNA oxidation effect on the organism, which leads to a decrease in performance. Michele explains how Selisseo® helps overcome oxidative stress.
Is Selisseo® available in powder and/or in liquid form? What about its chemical form and its stability when processed? To obtain answers to these questions, listen to the explanations of Anne Sophie Conjat.
Garros Fontinhas is talking about the different sources of selenium that are currently available to feed animals. He explains the benefits of OH-SeMet (Selisseo®) in terms of absorption, deposition and the formation of selenoproteins. A heat challenge? Check the explanation of Garros to see how Selisseo® can alleviate the decrease in performance.
Selisseo® improves the reproduction performance of breeders:
🞄 Fertility rate vs SS and SY
🞄 Hatchability vs SS and SY
🞄 Antioxidant status vs SS thus leading to a greater robustness of day-old chicks
Selisseo® alleviates the effects of stress on broiler growth:
🞄 Final body weight: Consistently improved compared to SS and SY
🞄 FCR: Consistently improved compared to SS and SY
🞄 Se deposition in the muscles vs SS and SY
Selisseo® sustains a better egg production in aging layers:
🞄 Egg production: More eggs/hen vs SS and SY
🞄 FCR vs SS and SY
🞄 Se-enriched egg: higher Se concentration in the egg vs SS and SY
Product names and availability may vary by region, please contact your local Adisseo representative for more information.
What is the most effective antioxidant strategy to improve the longevity and overall performance of laying hens?
The most effective strategy combines high-quality organic selenium with antioxidant vitamins to strengthen the bird’s natural defenses and sustain performance over time.
Adisseo recommends using Selisseo® (100% hydroxy-selenomethionine, OH-SeMet) as the core selenium source, supported by Microvit® antioxidant vitamins such as Microvit® E.
This antioxidant program helps protect hens’ cells against oxidative stress, and support energy metabolism, gut integrity and egg-forming tissues. Together, Selisseo® and Microvit® contribute to prolonged laying persistency, better egg quality, and improved flock resilience, especially in aging hens.
How do antioxidants help reduce oxidative stress and support the health of laying hens?
Antioxidants play a central role in maintaining hen health:
• Selisseo® (OH-SeMet) provides a highly bioavailable form of selenium that is efficiently incorporated into selenoproteins such as glutathione peroxidase: key enzymes that neutralize damaging free radicals.
• Microvit® antioxidant vitamins (including vitamin E) protect cell membranes and help keep tissues functional under metabolic and environmental pressure.
By reducing oxidative stress, these antioxidants safeguard the liver, gut lining, reproductive system, and immune cells, helping hens maintain production, welfare, and robustness across the entire laying cycle.
What signs indicate that laying hens may benefit from antioxidant supplementation?
Hens may require antioxidant support when producers observe:
• Gradual decline in laying persistency or egg output
• Decrease in eggshell thickness or strength, or more downgraded/cracked eggs
• Reduced egg freshness during storage (albumen quality)
• Lower feed efficiency or poorer nutrient utilization
• Weaker immune responsiveness or higher susceptibility to stress
• Declining vitality, feather quality, or resilience in aging flocks
In these situations, adding Selisseo® and complementary Microvit® antioxidants can help restore antioxidant balance and performance.
Which factors should poultry producers consider when choosing an antioxidant for their feeding program?
Producers should evaluate:
• Bioavailability: Organic selenium such as OH-SeMet (Selisseo®) is more efficiently absorbed and stored than inorganic selenium or yeast-based sources.
• Antioxidant synergy: Combining selenium with vitamin E (Microvit® E) ensures both enzymatic and membrane protection.
• Flock age: Aging hens have higher oxidative stress and benefit the most from a strong antioxidant program.
• Production targets: Whether the goal is egg quantity, shell quality, longer cycles, enriched eggs, or cost-optimization.
• Regulatory and product quality: Selisseo® enhances selenium transfer to eggs, supporting “selenium-enriched egg” claims where permitted.
Selecting a high-quality, consistent and well-documented antioxidant like Selisseo®, supported by Microvit® vitamins, helps ensure reliable performance.
What are the economic benefits of using antioxidants to support longevity and productivity in laying hens?
A robust antioxidant strategy centered on Selisseo® and Microvit® delivers multiple economic advantages:
• More saleable eggs thanks to improved eggshell strength and freshness
• Better feed efficiency, lowering feed cost per egg
• Longer productive lifespan, reducing flock replacement frequency
• Improved selenium transfer to eggs (+50% vs sodium selenite; +20% vs seleno-yeast), enabling premium marketing when regulations allow
• Lower losses from downgraded eggs or health-related setbacks
• Higher laying persistency and improved resilience in late production
Overall, Selisseo®, supported by Microvit® antioxidant vitamins, provides a high return on investment by enhancing performance, egg quality, bird health and production longevity.

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