Parag Acharya, Anand Prakash, Jessy Bagh
1Scientist (LPM), Regional Research & Technology Transfer Station (R.R.T.T.S.), O.U.A.T., Bhawanipatna.
2Assistant Professor (Poultry Science), Department of Livestock Farm Complex, College of
Veterinary Science, Rampura Phul, GADVASU, Punjab.
3Assistant Professor (LPM), College of Veterinary Science & Animal Husbandry, O.U.A.T., Bhubaneswar.
Role of Poultry in Food Security and Emerging Nutritional Strategies
Food security stands as one of the most critical global concerns of the 21st century. It goes beyond ensuring the availability and accessibility of food to also include its nutritional quality, safety, and long-term sustainability. With the global population continuing to grow, providing a consistent supply of nutrient-dense food is essential for public health, economic stability, and sustainable development.
Among all food-producing sectors, the poultry industry plays a pivotal role in supporting global food security. It is characterized by rapid production cycles, high feed efficiency, and relatively low production costs, making it an affordable source of animal protein. Poultry meat and eggs are rich in high-quality protein, essential amino acids, and micronutrients, which are particularly important in low- and middle-income countries where nutritional deficiencies remain widespread.
Chickens account for over 90% of the global poultry population and contribute nearly 89% of poultry meat and 92% of global egg production. The demand for poultry products is projected to rise sharply, with poultry meat consumption expected to increase by 121% and egg consumption by 65% between 2005 and 2050, driven by rising incomes, urbanization, and shifts toward animal-based diets.
Challenges in Poultry Production
Despite its growth and significance, the poultry industry faces considerable challenges. Rising input costs—such as feed, vaccines, medications, and labour—alongside the growing threat of infectious diseases and abiotic stressors like pollution and climate variability, threaten production efficiency and profitability.
Among these, heat stress (HS) is one of the most severe constraints, especially in broiler chickens. Elevated environmental temperatures compromise feed intake, growth rate, immune function, carcass quality, and survival. These negative impacts highlight the need for innovative and sustainable solutions that can improve poultry resilience and overall welfare.
Advancements in Nutritional Interventions
To overcome these challenges, several strategies have been employed to support poultry health and productivity. These include improved genetics, modern housing and ventilation systems, and the incorporation of functional feed additives—such as growth promoters, nutraceuticals, trace elements, and antioxidants—into poultry diets (Alagawany et al., 2020).
Trace minerals are of particular interest due to their roles in metabolism, immune function, and antioxidant defence. Selenium is an essential part of at least 25 selenoproteins, including glutathione peroxidase (GPx), a powerful antioxidant enzyme that protects birds from cellular damage. It helps maintain cellular homeostasis, boosts immunity, enhances growth, and supports fertility(Abd El-Hack et al., 2017). Adequate selenium levels are crucial for maintaining cellular homeostasis, immune competence, and reproductive efficiency in poultry (Hassan et al., 2020). Traditionally, poultry diets use either inorganic selenium (sodium selenite) or organic selenium (selenium-methionine). But these have limitations—either in bioavailability or cost. Nano-Se bridges the gap, offering the effectiveness of organic selenium with better safety and efficiency.
Nanotechnology in Poultry Nutrition
In recent years, nanotechnology has emerged as a promising tool in animal nutrition. The application of nanominerals in poultry feed has gained increasing attention due to their enhanced bioavailability and efficiency. Nanoparticles reduce antagonistic interactions in the gastrointestinal tract and allow for lower effective dosages with higher biological uptake. Furthermore, their use may help reduce environmental contamination by minimizing mineral excretion.
Nanoparticles have also shown antimicrobial properties, reducing pathogenic bacteria while promoting beneficial gut flora, which can improve gut health and overall performance For instance, zinc nanoparticles have been reported to boost broiler growth rates (Mohammadi et al., 2015), while selenium and silver nanoparticles have demonstrated potential in enhancing antioxidant status and mitigating oxidative stress.
Nano-Selenium: A Promising Nutritional Tool
Selenium (Se), named after the Greek goddess Selene, was discovered in 1817. Initially regarded as toxic, its importance as an essential trace element was only recognized in the 1950s (Schwarz and Foltz, 1957). Selenium naturally occurs in both inorganic and organic forms. The inorganic forms include selenate (Se⁶⁺), selenite (Se⁴⁺), and selenide (Se²⁻), whereas the organic forms, present in plant and animal tissues, include selenomethionine (SeMet) and selenocysteine (SeCys).
Selenium plays a central role in the structure of at least 25 known selenoproteins, with SeCys situated at their active sites. These selenoproteins are involved in essential physiological functions such as DNA synthesis, antioxidant defence, redox regulation, protein repair, thyroid hormone metabolism, and selenium transport and storage in body tissues. Selenium’s role in the activity of selenoproteins like glutathione peroxidase is critical for oxidative stress management, immune modulation, and metabolic regulation. The use of nano-Se in poultry diets shows promise in enhancing growth, improving feed efficiency, and increasing resistance to stressors such as heat stress. Its unique physicochemical properties enable it to act more effectively at the cellular level, supporting redox balance and boosting immune function under challenging environmental conditions.
Figure 1. Schematic overview of the biological effects of nano-selenium in poultry.
The Science behind the Benefits
- Nano-selenium (nano-Se) supplementation offers significant health advantages in poultry, including cholesterol reduction, protection of vital organs, and enhanced immune responses—particularly important during vaccinations such as those for Newcastle disease.
- Nano-Se, due to its nanoscale size and larger surface area, offers improved intestinal absorption and bioavailability when compared to conventional selenium sources. This is largely due to its ability to form nanoemulsions that enhance mucosal permeability. Although selenium does not directly influence feed intake or growth, its functional effects on performance are attributed to its incorporation into selenoproteins—such as thioredoxin reductase (TrxR) and glutathione peroxidase (GSH-Px)—which are vital in maintaining cellular redox balance and protecting against oxidative stress (Gangadoo et al., 2016).
- Moreover, nano-Se supports intestinal epithelial integrity, promoting better digestion and nutrient absorption (Gangadoo et al., 2018). A deficiency of selenium can lead to oxidative imbalance, impaired cellular function, and reduced overall productivity and reproductive performance in poultry.
- Available evidence suggests that dietary inclusion of SeNPs at a concentration of 0.9 mg/kg can positively influence gut health. Specifically, such supplementation has been associated with an increase in beneficial microbial populations, such as Lactobacillus and Faecalibacterium species, along with a higher production of short-chain fatty acids (SCFAs), notably butyric acid (Gangadoo et al., 2018). These findings highlight the potential of SeNPs to favourably modulate gut microbiota, which in turn may support enhanced immune function and improved intestinal integrity in poultry.
- Studies have shown that birds receiving dietary nano-Se at levels ranging from 0.15 to 1.2 ppm exhibit improved antioxidant capacity and immune responses. Under heat stress, nano-Se supplementation enhances levels of key antioxidants like GPx, reduces lipid peroxidation (measured by MDA), and boosts immunoglobulins such as IgM and IgG more effectively than other selenium forms (Senthil Kumaran et al., 2015). In laying hens, a dietary inclusion of 0.25 ppm nano-Se was found to elevate GSH-Px activity (Radwan et al., 2015). Likewise, broilers under heat stress benefitted from nano-Se with improved immunity, antioxidant defences, and growth outcomes (Mahmoud et al., 2016).
Limitations and Potential Risks of SeNPs
While selenium nanoparticles (SeNPs) are generally considered safe when used within recommended limits, excessive supplementation can pose health risks. In broiler diets, SeNP inclusion should not exceed 1.0 ppm, with the optimal range typically falling between 0.3 and 0.5 ppm (Selim et al., 2015). Intake beyond this range has been associated with adverse effects, including alterations in liver structure and signs of toxicity. For instance, administering higher levels of SeNPs (up to 4.25 ppm) has been shown to cause cellular stress in broilers, disrupting carbohydrate and fatty acid metabolism due to changes in protein expression. These issues are largely linked to the enhanced and uncontrolled absorption of nanoparticles, a consequence of their small size.
Animal studies using mice have further demonstrated the toxic potential of excessive selenium intake. Doses of 5 mg/kg body weight led to stunted growth, while 6.4 mg/kg induced liver alterations. At 8 mg/kg, mice exhibited symptoms of anaemia and increased mortality. These findings underscore the importance of further research to better understand the safety profile, toxicity thresholds, and long-term effects of SeNPs in poultry before widespread application (Nabi et al, 2020)
Conclusion
Selenium (Se) plays a crucial role in poultry nutrition due to its diverse health-promoting properties. Among various selenium sources, selenium nanoparticles (SeNPs) have emerged as a superior alternative, primarily because of their enhanced bioavailability and reduced toxicity compared to traditional forms. Research findings suggest that SeNPs can significantly boost poultry health and productivity. Unlike inorganic selenium, SeNPs minimize mineral antagonism in the gut, facilitating better absorption and lowering selenium excretion into the environment. Incorporating SeNPs into poultry diets also enriches selenium levels in eggs and meat, offering the potential to produce high-value functional foods for human consumption. Nevertheless, more in-depth investigations are needed to understand how SeNPs function within the poultry system and to determine safe and effective supplementation levels across different bird growth phases before large-scale implementation.