Phytogenics, Fermented Ingredients, Bee Products, Insect Additives, and Byproducts as Promising Dietary Supplements for Poultry

The prohibition of antibiotics in animal feed has driven significant interest in natural, plant-derived substances with bioactive properties. Among these, phytobiotics, feed additives of plant origin, have gained prominence due to their wide range of biological activities and multifaceted benefits (Abd El-Aziz et al., 2024) (Table 1). Phytobiotics are derived from herbs, spices, or various plant components, including leaves, roots, rhizomes, flowers, bark, fruits, and seeds, as well as their extracts. This category also includes non-hydrophobic compounds such as fructooligosaccharides, which are similarly plant-derived (Urban et al., 2024). Over the past two decades, the phytobiotics market has expanded significantly, fostering the development and commercialization of a wide array of products (Mohammadi Gheisar and Kim, 2017). These additives, often referred to as essential oils, functional oils, or botanical extracts, are collectively categorized as phytobiotics. Their key advantages include their natural origin, cost-effectiveness, environmental sustainability, and the absence of residues in animal-derived products (Bondar et al., 2023).

Phytobiotics are typically sourced from wild plants or cultivated crops, focusing on plant parts with the highest concentrations of bioactive compounds. Effective utilization depends on harvesting during the optimal vegetative stage, selecting appropriate collection sites, and implementing proper drying and storage techniques to preserve bioactive potency (Alem, 2024). Despite these measures, the stability of bioactive compounds decreases over time.

Many phytobiotics, particularly essential oils, contain compounds that can disrupt the cell membranes of pathogenic bacteria (Li et al., 2022). This leads to increased permeability and leakage of cellular contents, ultimately causing cell death. Additionally, phytobiotics can be effective against harmful bacteria like E. coli, Salmonella, and Clostridium, contributing to a healthier gut environment (Ferdous et al., 2019). Furthermore, phytobiotics, such as flavonoids and polyphenols, possess potent antioxidant properties. They can neutralize free radicals, which are unstable molecules that can damage cells and contribute to inflammation (Wang et al., 2024). This helps protect poultry from oxidative stress, which can be caused by factors like heat stress or disease. Moreover, phytobiotics can modulate inflammatory responses by inhibiting the production of pro-inflammatory cytokines (Greene et al., 2021). This helps reduce inflammation in the gut and other tissues, improving gut health. Some phytobiotics can also strengthen the gut barrier function by increasing the production of mucus and tight junction proteins (Mohammadi Gheisar and Kim, 2017). This helps prevent the leakage of harmful substances from the gut into the bloodstream (Kikusato, 2021). Certain phytobiotics, such as thyme and rosemary essential oils, can stimulate the secretion of digestive enzymes, which improve nutrient digestion and absorption (Pandey et al., 2023; El-Sabrout et al., 2023 b).

The main bioactive compounds in phytobiotics include tannins, saponins, essential oils, flavonoids, glycosides, and alkaloids (Staniek et al., 2013; Liu et al., 2019; Pandey et al., 2023). In monogastric animal nutrition, phytobiotics provide multiple benefits: they enhance feed palatability, stimulate appetite, regulate gastrointestinal (GI) function, and mitigate digestive disorders such as diarrhea (Cairo et al., 2018). Additionally, they influence GI motility, gastric secretions, and intestinal pH. Certain phytobiotics exhibit protective effects (e.g., fenugreek and flax), regulate metabolism (e.g., knotgrass and nettle), or improve the quality of animal-derived products (e.g., garlic and marigold flowers) (Krauze, 2021; Urban et al., 2024). A growing body of research highlights the potential of phytobiotics as alternatives to antimicrobials (Dhama et al., 2015; Aljumaah et al., 2020), coccidiostats (Dhama et al., 2015; Paraskeuas et al., 2024), and antiparasitics (Dhama et al., 2015; Krauze et al., 2021). Phytobiotics also function as immunostimulants (Ebrahimi et al., 2015), supporting animal health and welfare by improving gut integrity and enhancing productive performance. For instance, Kim et al. (2013) demonstrated that supplementation with turmeric rhizome extract improved resistance to experimental infections with Eimeria maxima and Eimeria tenella. This was evidenced by increased body weight gain, reduced fecal oocyst shedding in Eimeria tenella (but not E. maxima), and decreased gut lesions in E. maxima infections compared to birds fed a non-supplemented diet.

In poultry nutrition, where commercial hybrids require specialized diets to achieve their genetic potential, phytobiotics have proven effective. In vitro and in vivo studies have confirmed their efficacy in improving the performance of broilers (Windisch et al., 2008; Hashemipour et al., 2014; Khan et al., 2017), layers (Ghasemi et al., 2010; Arpášová et al., 2018; Lokaewmanee, 2019), turkeys (Bampidis et al., 2005) and ducks (Lewko et al., 2024). Ürüşan and Bölükbaşi (2017) and El-Sabrout et al. (2023 b) reported that supplementing broiler diets with turmeric powder (0–10 g/kg) enhanced growth performance and gut health, with the highest level (10 g/kg) significantly reducing feed intake. Additionally, Sethy et al. (2016) showed that broiler chickens receiving dietary curcumin at 5 and 10 g/kg feed for 42 days experienced growth rate increases of 18% and 20%, respectively, compared to controls. Similarly, Durrani et al. (2006) observed a 12% growth rate increase and a 33% reduction in feed conversion ratio (FCR) in broilers supplemented with curcumin at 5 g/kg for 35 days. Consistent results were reported by Al-Sultan (2003), while a meta-analysis by Ogbuewu et al. (2022) found that turmeric supplementation (0.2–11 g/kg feed) improved FCR and average daily gain with minimal increases in feed intake. Herve et al. (2019) report that the oral administration of ginger rhizomes essential oil in laying Japanese quails for 12 consecutive weeks at doses of 100 and 150 µl/kg positively influenced egg weight and yolk antioxidant status. The same authors also observed that ginger rhizome essential oil significantly reduced cholesterol levels in serum and egg yolks, without adversely affecting feed intake or body weight gain in quails.

Phytobiotics improve feed organoleptic properties, influencing feed intake and digestive enzyme secretion. One of their most notable effects is the stimulation of digestive secretions, including saliva, digestive enzymes, bile, and mucus, which enhances nutrient digestibility and reduces nutrient excretion. This contributes to a lower environmental impact of poultry farming (Govinthasamy et al., 2016). Furthermore, certain phytobiotics exhibit prebiotic properties, modulating the intestinal microbiome to improve animal welfare, food safety, and public health (Tabashsum et al., 2019). As an example, Kosti et al. (2020) observed the effects of curcumin on the gut microbiota of laying hens. The study found that curcumin supplementation significantly altered the composition of the gut microbiota in the hens, increasing the abundance of beneficial bacteria such as Lactobacillus and Bifidobacterium, while decreasing the abundance of harmful bacteria such as Escherichia coli and Salmonella. Phytobiotics antioxidant properties, as demonstrated by Hosseini-Vashan et al. (2016), Arain et al. (2018), and Selvam et al. (2018), help animals tolerate stressors, sustain productivity during critical periods, and improve overall welfare.

Fermented feed additives for poultry have gained popularity in recent years due to their multitude of benefits for poultry health and performance. By fermenting feed ingredients, beneficial microorganisms such as lactobacilli and yeast are able to break down complex carbohydrates and proteins into more easily digestible forms (Sugiharto and Ranjitkar, 2019; Predescu et al., 2024). Therefore, the fermentation process can generate probiotic bacteria that help to maintain a balanced gut flora, prevent the growth of harmful pathogens, and enhance nutrient absorption in the digestive tract (Dimidi et al., 2019). It can stimulate the production of mucin, a protective layer in the gut; in turn, this can contribute to a healthier gut lining and protection against pathogens (Peng et al., 2022; Predescu et al., 2024). Additionally, fermentation has been shown to increase the palatability of the feed, leading to increased feed intake and improved growth rates in poultry (Sugiharto and Ranjitkar, 2019; Zhu et al., 2023). Hence, poultry fed fermented feed additives are less susceptible to digestive disorders and diseases, leading to better gut health, immunity, and productivity (Peng et al., 2022; Elghafar et al., 2024; Han et al., 2024).

Fermented feed substances exert their beneficial effects in poultry diets through a multifaceted mechanism of action, primarily centered on modulating the gut micro-biota and enhancing intestinal health. The fermentation process, driven by beneficial microorganisms like lactic acid bacteria and yeasts, produces a range of bioactive compounds, including organic acids (e.g., lactic, acetic), bacteriocins, enzymes, and short-chain fatty acids (SCFAs). These compounds contribute to a reduction in gut pH, creating an unfavorable environment for pathogenic bacteria such as Salmonella and E. coli. Furthermore, bacteriocins directly inhibit the growth of these pathogens by disrupting their cell membranes. The increased concentration of SCFAs, particularly butyrate, serves as a primary energy source for intestinal epithelial cells (enterocytes), promoting their proliferation and strengthening the intestinal barrier function. This improved barrier integrity minimizes the translocation of harmful bacteria and toxins into the bloodstream, thereby reducing systemic inflammation and enhancing overall immune function (Sun et al., 2021; Lv et al., 2022; Fu et al., 2023).

Fermented feed also contributes to improved nutrient digestibility and absorption through the production of exogenous enzymes and the modification of feed components. Fermentation processes can break down complex carbohydrates, proteins, and phytate, releasing nutrients that are otherwise unavailable to poultry. The enzymes produced during fermentation, such as proteases, amylases, and cellulases, further enhance the digestion of these substrates in the gastrointestinal tract. Moreover, the reduction of antinutritional factors like phytate improves the bioavailability of minerals such as phosphorus, calcium, and zinc. The improved nutrient utilization not only enhances growth performance and feed efficiency but also reduces the excretion of undigested nutrients into the environment, contributing to a more sustainable poultry production system (Gowthamraj et al., 2021; Li et al., 2021).

Furthermore, fermented feed can significantly modulate the poultry immune system, both locally within the gut and systemically. The presence of microbial metabolites, including SCFAs and bacteriocins, stimulates the production of immunoglobulins (IgA) in the intestinal mucosa, enhancing local immunity. Additionally, FFS can influence the balance of pro-inflammatory and anti-inflammatory cytokines, promoting a more balanced immune response. This immunomodulatory effect helps to improve the bird’s resistance to diseases and reduce the need for antibiotic interventions. Furthermore, the altered gut microbial composition resulting from FFS supplementation can lead to enhanced gut-associated lymphoid tissue (GALT) development and function, strengthening the overall immune surveillance and response capabilities of the poultry (Zhu et al., 2020; Predescu et al., 2024).

Generally, the use of fermented feed additives represents a promising strategy for improving the health and productivity of poultry in a sustainable and natural way (Xu et al., 2023; Predescu et al., 2024). Liu et al. (2021) studied the nutritional quality of the feed before and after fermentation and the effect of this process on the gut health of the laying hens during the laying peak period. They found that fermented “corn-soybean meal mixed feed” can improve intestinal morphology and barrier functions of laying hens, possibly by altering the cecal microbiome. Moreover, Elghafar et al. (2024) revealed that including fermented wheat germ extract in the broiler chicken diet by 0.2% positively impacted the birds’ growth performance, health, and carcass quality. Furthermore, the dietary fermented feed is correlated with decreasing the antinutrient concentration in vegetal matrices usually used for broiler nutrition, in addition to converting certain antinutrients into beneficial substances for animal organisms (Xu et al., 2023; Predescu et al., 2024).

Fermentation of animal feed is useful as compounds with high molecular mass are converted into energy and compounds with lower molecular mass in the presence of enzymes produced mainly by bacteria and yeasts. The bioactive compounds produced during fermentation, such as organic acids and antimicrobial peptides, have also been found to enhance the health of the animal microbiome, modulate immune responses, and increase the birds’ resistance to infectious diseases (Peng et al., 2022; Xu et al., 2023; Elghafar et al., 2024). By strengthening the immune system, fermented feed additives help poultry cope with stress factors, such as heat or disease challenges, and maintain their health and performance levels. Furthermore, fermented feeds can positively affect intestinal morphology, particularly increasing villus height and crypt depth, which is indicative of better nutrient absorption (Predescu et al., 2024).

Based on the previous findings, employing fermented feeds in poultry nutrition has shown promising outcomes for growth performance, immunological response, and intestinal health. However, several factors must be considered, including feed composition, fermentation conditions, and the poultry production system’s specialized requirements.

Bee products have long been recognized for their potential health benefits in humans and animals. In recent years, there has been growing interest in using bee products in poultry nutrition. One of the most commonly studied bee products for poultry nutrition is bee pollen. Bee pollen is a highly nutritious substance that contains essential amino acids, vitamins, minerals, and antioxidants (El-Sabrout et al., 2023 b; Pawłowska, 2024).

Bee products, such as propolis, honey, and bee pollen, exert their beneficial effects in poultry primarily through their complex bioactive compounds. Propolis, rich in flavonoids and phenolic acids, exhibits potent antimicrobial and antioxidant properties. These compounds disrupt bacterial cell membranes, inhibit enzyme activity, and scavenge free radicals, thereby improving gut health and reducing oxidative stress. Honey, containing diverse sugars, enzymes, and organic acids, acts as a prebiotic, promoting the growth of beneficial gut microbiota like Lactobacillus and Bifidobacterium. This modulation of gut flora enhances nutrient absorption, strengthens the intestinal barrier, and improves immune function. Bee pollen, with its abundant vitamins, minerals, and amino acids, provides essential nutrients and boosts immune responses by stimulating lymphocyte proliferation and cytokine production. Collectively, these products enhance poultry performance by improving gut integrity, antioxidant status, and immune competence (Hassan et al., 2018; Khalifa et al., 2021; Schell et al., 2022; Abd El-Aziz et al., 2023; El-Sabrout et al., 2023 b).

The immunomodulatory effects of bee products are central to their efficacy as poultry feed additives. Propolis, for instance, has been shown to modulate both innate and adaptive immune responses. Its phenolic compounds interact with toll-like receptors (TLRs), triggering the production of cytokines like interleukins and tumor necrosis factor-alpha (TNF-α), which are crucial for immune cell activation and pathogen clearance. Honey’s oligosaccharides and peptides can enhance the activity of macrophages and natural killer (NK) cells, bolstering the bird’s defense mechanisms against pathogens. Bee pollen’s polysaccharides stimulate the proliferation of B and T lymphocytes, enhancing antibody production and cell-mediated immunity. These combined immunomodulatory actions result in improved resistance to diseases and a reduced need for antibiotic interventions, contributing to healthier and more sustainable poultry production (Muzzolon et al., 2021; Oršolić and Jazvinšćak Jembrek, 2022; Schell et al., 2022; Abd El-Aziz et al., 2023).

Beyond antimicrobial and immunomodulatory effects, bee products also influence metabolic processes in poultry. Honey’s readily available sugars provide a quick energy source, improving growth performance, especially during stress periods. Enzymes present in honey, such as invertase and amylase, aid in carbohydrate digestion, enhancing nutrient utilization. Propolis and bee pollen’s antioxidant components, including flavonoids and polyphenols, protect cellular lipids and proteins from oxidative damage, maintaining cellular integrity and function. These antioxidants also enhance the activity of endogenous antioxidant enzymes like superoxide dismutase (SOD) and catalase, further mitigating oxidative stress. Moreover, some bee product components have been shown to positively affect lipid metabolism, reducing serum cholesterol and triglyceride levels. This comprehensive impact on metabolic pathways contributes to improved feed conversion efficiency, enhanced meat quality, and overall better health in poultry (Schell et al., 2022; Al-Kahtani et al., 2022; Abd El-Aziz et al., 2023).

Research has shown that supplementing poultry feed with bee pollen can improve overall health, egg production, and feed efficiency in chickens (Demir and Kaya, 2020; Nemauluma et al., 2023). Another bee product that has shown promise in poultry nutrition is propolis. Propolis is a resin-like substance that bees collect from plant buds and use to seal cracks in their hives. Propolis has antibacterial, antifungal, and anti-inflammatory properties, making it a potential natural alternative to antibiotics in poultry farming (Abd El-Aziz et al., 2023; Abd El-Ghany, 2024). Studies have found that adding propolis to poultry feed can improve immune function, reduce oxidative stress, and enhance growth performance in chickens (Mahmoud et al., 2016). Furthermore, propolis has been shown to have beneficial effects on egg quality and shell strength in laying hens (Mahmoud et al., 2016; Bölükbaşı et al., 2023).

Bee venom, also known as apitoxin, is a unique bee product that has shown potential benefits for poultry nutrition (Abd El-Aziz et al., 2023). It is a complex mixture of proteins, peptides, and enzymes that have been reported to possess antimicrobial, anti-inflammatory, and immunomodulatory properties. These bioactive compounds in bee venom have the potential to enhance the overall health and performance of poultry (El-Banna et al., 2023; Bava et al., 2023). Several research studies have shown that supplementation of bee venom in poultry diets can improve growth performance, feed conversion ratio, and immunity against pathogens (Han et al., 2010; El-Banna et al., 2023). In addition to its antimicrobial properties, bee venom has also been reported to have antioxidant effects, which can help reduce oxidative stress and improve the overall health of poultry (Abd El-Aziz et al., 2023; Bava et al., 2023). Oxidative stress is a major concern in poultry production as it can lead to various health issues and reduced productivity (Mohamed et al., 2025). By including bee venom in poultry diets, producers may be able to mitigate the negative effects of oxidative stress and promote overall health and well-being in their flocks (Qin et al., 2023; Abd El-Aziz et al., 2023). Furthermore, bee venom has been shown to stimulate the immune system in poultry, leading to increased resistance against infectious diseases (Han et al., 2010; Raheel et al., 2020).

Based on the previous findings, bee products offer a natural and sustainable way to enhance poultry nutrition and health. As the demand for antibiotic-free and organic poultry products continues to grow, bee products could provide a viable solution for improving poultry production without the use of synthetic additives. Further research is needed to better understand the optimal dosage, timing, and mode of administration of bee products in poultry nutrition. Additionally, precautions should be taken when handling and administering bee venom to avoid any potential allergic reactions in poultry. By harnessing the potential of bee products, the poultry industry can work towards more sustainable and healthful practices for both animals and consumers.

Soybean and fish meals, traditional protein sources in poultry diets, are linked to significant environmental issues, including greenhouse gas emissions, deforestation, and water pollution. Consequently, there has been a growing interest in utilizing alternative protein sources, including both plant and animal-based proteins, such as insect meal (El-Sabrout et al., 2023 b; Khalifah et al., 2023). Recently, insect meal has been increasingly recognized as a protein source in chicken diets, potentially reducing feed costs and enhancing profitability through the use of fresh insects in small-scale poultry production (Sajid et al., 2023). Therefore, insects became a viable and sustainable alternative to traditional protein sources, delivering similar nutritional benefits and a diminished environmental impact (Veldkamp et al., 2022; Belhadj Slimen et al., 2023) (Figure 2).

Figure 2.

Edible insects as feed additives to poultry diets

The use of insect products in poultry nutrition has gained traction as a cost-effective and sustainable alternative to traditional feed sources. Insects are rich in protein, essential amino acids, and other nutrients, demonstrating their potential to enhance poultry birds’ growth and improve their feed conversion ratios (Al-Qazzaz and Ismail, 2016; Belhadj Slimen et al., 2023). Moreover, insects can be raised on organic waste, making them an environmentally friendly option for feed production. However, using these products in poultry diets still addresses several challenges, including governmental limitations and consumer acceptance.

For the development of insect-based diets, several insect species have been the subject of extensive investigation. The locusts (Schistocerca gregaria, Locusta migratoria, and Oxya sp.), black soldier fly (Hermetia illucens), common housefly (Musca domestica), meal-worm (Tenebrio molitor), mopane worm (Gonimbrasia belina), silkworm (Bombyx mori), field cricket (Gryllus bimaculatus), grasshoppers (Caelifera suborder), westwood insect (Cirina forda), and earthworms (Lumbricus terrestris) are some of these species (Makkar et al., 2014; Khalifah et al., 2023). However, insects can be utilized in live (fresh), dried, and paste forms for poultry diets (Elahi et al., 2020). A desiccated insect is deemed appropriate for chicken feed because of the moisture level in fresh or live insects, which promotes decomposition, antibacterial activity, and the Maillard reaction (Kröncke et al., 2019). The exoskeleton of insects primarily comprises chitin, which enhances the immune system of chickens (Al-Qazzaz and Ismail, 2016); however, chickens are incapable of synthesizing chitin (Bovera et al., 2016). Chitin and its derivatives can activate innate immune cells (Lee et al., 2008). Broiler chickens consuming a diet supplemented with mealworm meal have enhanced disease resistance and immunological response attributed to the prebiotic properties of chitin (Bovera et al., 2015). Chitin in the feed inhibits the proliferation of Salmonella, Salmonella enterica serovar Typhimurium, and Escherichia coli in broiler chickens (Menconi et al., 2014). Moreover, the hypocholesterolemic and hypolipidemic characteristics of chitin result in leaner meat by reducing body fat in broiler chickens (Gasco et al., 2018).

Among livestock, neither mammals nor poultry produce chitin; thus, insects represent a viable source (Komi et al., 2018). Modulating gut microbiota through insect feeding may affect antibody titers in avian species (Ido et al., 2015). In the same manner, Khempaka et al. (2011) indicated that administering shrimp chitin to broiler chickens suppressed the proliferation of foodborne pathogens including Salmonella in the intestine. Incorporating yellow mealworm (Tenebrio molitor) and super mealworm (Zophobas morio) into the diets decreased cecal populations of Salmonella spp. and E. coli in broiler chicks (Islam and Yang, 2017). A study documented that using yellow mealworm in the diet of commercial broilers stimulated immune response by reducing albumin to globulin ratio and enhancing resistance against diseases and these benefits could be due to the presence of chitin having probiotic effects (Bovera et al., 2015). Comparable results were observed in commercial layers provided with diets containing black soldier fly meal (Marono et al., 2017).

Insects are acknowledged as vectors of disease, posing a risk of transmission of insect-borne diseases to humans as well as in poultry (Makkar et al., 2014). The black soldier fly (Hermetia illucens) is devoid of any pathogenic agents; conversely, the housefly (Musca domestica) harbors Entomophthora spp. fungus, the house cricket (Acheta domesticus) carries Metarhizium sp. fungus and cricket paralysis virus, and the mealworm (Tenebrio molitor) is a vector for Beauveria bassiana fungus (Eilenberg et al., 2015). Insect larvae synthesize antimicrobial peptides to defend against microbial infections, and these peptides may also be effective in poultry (Józefiak et al., 2017). Furthermore, adequate processing of insects may mitigate chemical hazards and render them gluten-free (Mancini et al., 2020). Insects possess antimicrobial peptides effective against antibiotic-resistant bacteria, viruses, fungi, and parasites, and are utilized in treatments for wounds, infections, cancer, flatulence, phlegm, spasms, and anticoagulation. The anti-microbial peptide P5 serves as an antibiotic alternative and functions as a growth promoter (Choi et al., 2013). Moreover, antimicrobial peptides enhance nutrient digestibility, gastrointestinal health, growth performance, and immunological function (Wang et al., 2016). The dark coloration of insect cuticles is attributed to the bioactive phenolic chemical melanin, which possesses antifungal and antibacterial properties and aids in the prevention and treatment of liver disorders, stress, and malignancies (Van Huis, 2022). Furthermore, insects are abundant in fatty acids, possessing antibacterial capabilities; among them is lauric acid which is recognized for its antibacterial and antiviral properties (Lieberman et al., 2006).

The fiber content of insect meals, especially chitin, acts as a prebiotic, promoting the growth of beneficial bacteria in the poultry gut. This modulation of the gut microbiota can improve nutrient digestibility and absorption. Studies have demonstrated that insect-based diets can increase the population of beneficial bacteria, such as Lactobacillus and Bifidobacterium, while reducing the abundance of pathogenic bacteria, such as Escherichia coli. This shift in microbial composition can enhance the production of short-chain fatty acids (SCFAs), which serve as an energy source for intestinal epithelial cells and contribute to gut barrier integrity. Additionally, the enzymes present in insect meals, such as proteases and lipases, can aid in the digestion of feed components, improving nutrient utilization. (Wu et al., 2018; Komi et al., 2018; Iannas et al., 2021; Loponte et al., 2021).

Edible insects, particularly those rich in chitin, such as mealworms and black soldier fly larvae, can significantly influence poultry immune responses (Al-Qazzaz and Ismail, 2016; Solecka and Zonenberg, 2024). Chitin, a polysaccharide found in insect exoskeletons, acts as a pathogen-associated molecular pattern (PAMP), triggering innate immune pathways. It interacts with pattern recognition receptors (PRRs) like toll-like receptors (TLRs), leading to the activation of NF-κB and subsequent production of cytokines, such as interleukins and interferons. This immunomodulatory effect enhances the bird’s resistance to pathogens and improves overall gut health. Studies have shown that the inclusion of insect meals in poultry diets can increase the levels of IgA in the intestinal mucosa, indicating enhanced mucosal immunity (Biasato et al., 2019; Gasco et al., 2018). Furthermore, peptides derived from insect proteins may possess antimicrobial properties, directly inhibiting bacterial growth and contributing to a balanced gut microbiota.

Edible insects also are rich in unsaturated fatty acids, particularly omega-3 and omega-6 fatty acids, which can improve lipid metabolism in poultry. The inclusion of insect meals in poultry diets can reduce the levels of triglycerides and cholesterol in the blood and tissues, leading to healthier meat products. Furthermore, insects contain antioxidants, such as tocopherols and polyphenols, which can protect cells from oxidative damage. These antioxidants can improve the antioxidant status of poultry, enhancing meat quality and shelf life. The presence of these compounds can help to reduce the amount of lipid oxidation within poultry meat (Kritas et al., 2021; Schilling et al., 2021).

However, it is essential to note that the specific effects of edible insect substances on poultry can vary depending on the insect species, processing methods, and inclusion levels in the diet. Further research is needed to fully elucidate the mechanisms of action and optimize the use of insects as feed additives in poultry production.

Research demonstrated that insect meal can partially or entirely substitute soybean cake and fishmeal in the diets of broiler and layer chickens without compromising production performance or feed efficiency (Elahi et al., 2020; Adli, 2021). The incorporation of black soldier fly larvae in poultry feed has shown enhancements in production performance, feed efficiency, and meat quality (Nampijja et al., 2023; Salahuddin et al., 2024). It may affect birds’ growth performance characteristics by modifying gut flora (Detilleux et al., 2022). Furthermore, Sedgh-Gooya et al. (2021) indicated that including yellow mealworms (Tenebrio molitor) in broiler feeds enhances growth performance during the beginning phase. Incorporating small amounts of super mealworm or yellow mealworm into broilers’ meals can enhance their growth performance (Benzertiha et al., 2020). Similarly, Ballitoc and Sun (2013) reported the beneficial effects of yellow mealworm supplementation on total feed consumption and weight gain in broiler chickens. These enhancements may result from an improved daily feed intake, which is connected with the palatability of insect meal incorporated into the diet (Islam and Yang, 2016). Working on Japanese quails, Zadeh et al. (2019) concluded that supplementing yellow mealworms in diets also enhances quails’ growth performance, gut morphology, and meat quality. Research evaluating the suitable substitution of soybean meal with mealworm indicated that black soldier fly meal can be a safe and better alternative to soybean meal without having any detrimental effects on intestinal health and blood biochemistry of commercial broilers (Kim et al., 2021). Similarly, another study reported that the provision of yellow mealworms to free-range chicken can regulate digestive tract and intestinal microbiota without any adverse effect on gut health (Biasato et al., 2018). A study conducted by Borrelli et al. (2017) found that a food regimen using yellow mealworm did not influence the health status of laying hens. Administering chitin to fish has diminished pathogen proliferation by fostering the development of advantageous gut microbiota, resulting in enhanced growth performance and health (Karlsen et al., 2017). In a study of red sea bream, supplementation of housefly larval diet revealed a beneficial impact that triggers the innate immune system in response to Edwardsiella tarda infection (Ido et al., 2015). Ido et al. (2015) suggested that the immunomodulatory effects of insect-based diet might be attributed to the presence of chitin in the exoskeleton of insects. However, the provision of live insect larvae did not influence immune response or mucin composition when administered to commercial fast-growing broiler chickens (Colombino et al., 2021). Contrarily, another study on jumbo quail reported that provision of black soldier fly larvae meal in greater amounts may compromise autoimmune response (Mbhele et al., 2019).

A viable approach to render insect meal production economically feasible is to reduce the inclusion level of insect meal in broiler diets, utilizing its potential as a nutritional additive to improve health while investigating feed intake beyond its nutritional value. Conserving 0.8% of soybean meal only in broiler chicken feed in Brazil can translate to the utilization of these grain quantities for human consumption. This indicates a significant potential savings of this grain once the global use of insect meal becomes feasible. This scenario might significantly advance sustainable development goals and is also encompassed within circular economy principles (Tavares et al., 2022).

Insects have historically been collected and consumed in several culinary traditions, including those of Mexico, China, and Australia, without a defined regulatory framework. In light of concerns regarding climate change and the sustainability of food systems, the industrial farming of insects for consumption and animal feed is increasingly gaining popularity in both developed and developing nations. Two issues arise concurrently with this expansion: the first is the absence of local regulation, and the second is the inconsistency of regulatory frameworks across international borders. Numerous local enterprises seek to export their insect products globally; however, the regulatory requirements and variances among nations hinder efforts to market and sell these products (Lähteenmäki-Uutela et al., 2021). All principal stakeholders believe that the production of insects and their applications in animal feed and human food require regulation to ensure safety. In this regard, there is consensus to establish regulatory frameworks based on a scientific risk assessment methodology. Specific and clear regulations equalize competition, stimulate investments, enhance trust, and standardize the industry (Van der Spiegel, 2016). Allegretti et al. (2018) proposed that public and commercial entities should collaborate to establish a global regulatory framework for insects within sustainable food systems. Substantial effort is required to support and advance this significant nascent industry. All parties, including government legislators, industry participants, and the scientific community, must collaborate to establish uniformity and determine a path ahead both locally and worldwide.

The global warming potential (GWP) of insect protein may exceed that of broiler protein, contingent upon the production region and the bug species utilized, even when insects are consumed directly by humans. From this perspective, our study indicates that existing practices of insect production for feed are insufficiently efficient to meaningfully reduce GWP in European food consumption. The study reveals that a prerequisite for achieving a GWP reduction in protein consumption is the demonstration of the safety of side streams, hence permitting their usage as insect feed. Regardless of the outcome, a judicious selection of bug species for human consumption could yield substantial environmental sustainability advantages. In addition to hygiene and legislation, technological development decisions can significantly influence the extent to which insect-based protein may mitigate food-related carbon footprints. The energy sources significantly influence prospective climate advantages, necessitating effective scaling for financial affordability to customers (Vauterin et al., 2021).

Agro-industrial byproducts (AIBPs) that are not designated for human consumption may serve as better alternatives to traditional feedstuff for poultry and animal nutrition. AIBPs can facilitate the production of animal products without instigating food-feed competition or competing for land, hence, promoting economic, social, and environmental sustainability. Furthermore, different bioactive components present in AIBPs have the potential to be developed as nutraceuticals that can improve gut health and overall performance of poultry birds (Georganas et al., 2023). Nutrient variability among countries must be standardized, and potential hazards, including mycotoxins and pesticides, should be eradicated. Furthermore, risks associated with AIBPs, such as mycotoxins, require enhanced regulation and effective implementation of control measures. Modern processing technologies, novel types/classifications, and correct developmental strategies stimulate the application of AIBPs in animal nutrition (Georganas et al., 2023).

Byproducts, often derived from agricultural or industrial processes, exert their effects through various mechanisms of action. Many of them, particularly those rich in fiber or prebiotics, can influence the composition and activity of the gut microbiota (Thomson et al., 2021; Readh et al., 2023). For example, certain plant byproducts contain oligosaccharides that serve as substrates for beneficial bacteria, such as Lactobacillus and Bifidobacterium (Yue et al., 2024). This selective stimulation of beneficial bacteria can lead to competitive exclusion of pathogenic bacteria, improved gut barrier function, and enhanced immune responses (Fathima et al., 2022). This modulation is a key aspect of how many byproduct feed additives can improve the health and performance of poultry.

Furthermore, some byproducts contain enzymes or other bioactive compounds that can improve nutrient digestibility and absorption. For instance, certain plant byproducts may possess inherent enzymes that aid in the breakdown of complex carbohydrates or proteins (Khan et al., 2024). From another viewpoint, many plant-derived byproducts are rich in antioxidants, such as polyphenols and flavonoids, which can protect cells from oxidative damage. These antioxidants can enhance the immune system by reducing inflammation and improving immune cell function (El-Sabrout et al., 2024). Additionally, some byproducts may contain immunomodulatory compounds that directly stimulate immune responses (Phillips et al., 2023). However, it is important to note that the specific mechanisms of action can vary depending on the type of byproduct, its composition, and the dosage used. Further research is ongoing to fully elucidate the complex interactions between byproduct feed additives and poultry physiology.

AIBPs are comprised of numerous bioactive chemicals that have antioxidant, immunological modulator, and antibacterial functions. These properties make them ideal feed ingredients in the diet of poultry to enhance growth, welfare, health, and productivity. Several studies reported the use of byproducts in poultry feed; for example, dried apple pomace enhances productivity at levels of up to 6 and 25% in commercial broiler and layer diets, respectively (Ghaemi et al., 2014; Colombino et al., 2020). Additionally, dried sweet orange peel and dried citrus pulp may be added up to 3 and 10% in the diet of fast-growing broilers, respectively (Diaz-Vargas et al., 2018; Zoidis et al., 2022). Mixed results were noted when sunflower meal was added to the diets of goose and ostriches; however, sunflower meal up to 15% with a mixture of enzymes in the diet of commercial broiler exhibited positive results related to growth performance and overall health (Araújo et al., 2011). Byproducts from the herbal industry, such as the endosperm of milk thistle (Silybum marianum) – a byproduct of silymarin production – can also be repurposed as feed additives, provided they retain sufficient bioactive content (Guo et al., 2024).

The incorporation of sunflower meal in the hen’s diet, at levels up to 25%, did not yield adverse effects (Shi et al., 2012). Dried distillers’ grain with solubles can be incorporated at levels of up to 24% in broiler diets (Shim et al., 2011) and up to 25% in laying hen diets (Masa’deh et al., 2011), however, findings varied according to the growth phase. Grape pomace can be incorporated at levels up to 10% in broiler diets (Ebrahimzadeh et al., 2018) and up to 6% in hen diets (Kara et al., 2016). Olive pulp with the addition of citric acid can be added up to 10% whereas olive cake may be incorporated up to 20% in the diet of commercial broiler and layer chickens (Pecjak et al., 2020). Fermented or raw pomegranate pulp could be added at the level of 2% in the poultry diet (Hosseini-Vashan et al., 2019). Sugar beet pulp may be included in broiler diets at concentrations of up to 5% (Jiménez-Moreno et al., 2013). However, several strategies should be found to limit the nutritional heterogeneity of ABIP among nations. However, AIBPs possess deficiencies and constraints, including the existence of antinutritional components and chemical risks. The significance of managing possible dangers in AIBPs must be underscored by appropriate legislation and awareness of the various players involved; for instance, the implementation of effective farming techniques and the reduction of anti-nutritional elements in AIBPs. Moreover, most research examined herein exhibited significant discrepancies in the characterization of extracts regarding their biological features upon evaluation. Contemporary processing techniques, novel classifications, and suitable developing strategies are broadening the utilization of AIBPs as animal feed in chicken production (Georganas et al., 2023). Consequently, because of the significant regional variability in the availability and pricing of AIBPs, the incorporation of these AIBPs as functional feed ingredients in chicken diets should be tailored to the specific availability and cost of each byproduct. Furthermore, due to the nutritional diversity of these byproducts, proximate analysis prior to feeding is essential for managing animal diets and reducing expenses (Georganas et al., 2023).

Subsequent research should validate the effectiveness of agro-industrial residues and their byproducts as alternatives to traditional feedstuffs in poultry nutrition. Investigating bioprocessing techniques for transforming food waste into value-added goods is a crucial advancement in sustainable waste management and the circular economy. It is anticipated that the advancement of technology and market expansion will yield substantial economic growth and environmental advantages in this sector (Wang and Qi, 2024).

The economic viability of incorporating feed alternatives into poultry diets necessitates a nuanced cost-benefit analysis. The economic feasibility of integrating phytogenics, fermented ingredients, bee products, insect additives, and byproducts into poultry feed formulations is a complex issue requiring a multi-faceted cost-benefit analysis. Firstly, the inherent variability in sourcing and processing significantly impacts the economic landscape.

Phytogenics, derived from plant extracts, present a more nuanced picture (Akosile et al., 2023). The cost-effectiveness of phytogenics is contingent on the specific plant species, extraction method, and concentration of active compounds. For example, essential oils from readily available plants may be relatively inexpensive, while rare or exotic extracts require specialized cultivation and processing, resulting in higher costs (Smith and Jones, 2020). Furthermore, the efficacy of phytogenics in enhancing poultry performance is dose-dependent, requiring precise formulation to achieve optimal results without incurring excessive costs. Phytogenics and fermented ingredients occupy an intermediate position, offering a balance between cost-effectiveness and potential improvements in poultry health and performance (Garcia et al., 2019; Shehata et al., 2022). However, the cost of these items can be greatly influenced by the level of processing they undergo. Fermented ingredients, produced through microbial fermentation of feedstuffs, offer potential benefits in improving nutrient digestibility and gut health (Xu et al., 2023). However, the energy and resource inputs required for fermentation processes, including substrate preparation, microbial cultivation, and product drying, can significantly influence production costs. The selection of microbial strains and fermentation conditions plays a crucial role in optimizing nutrient conversion and minimizing energy consumption.

Bee products, such as propolis, pollen, and royal jelly, exhibit diverse biological activities with potential applications in poultry health (Abd El-Aziz et al., 2023). However, their availability is inherently limited by specific product types and environmental factors, leading to price volatility (Lee et al., 2022; El-Sabrout et al., 2023 b). The standardization of bee product quality and composition is also challenging, requiring rigorous analytical methods to ensure consistent efficacy. Therefore, a comprehensive evaluation must consider not only the initial procurement cost but also the long-term impacts on feed conversion ratios, disease resistance, and overall poultry productivity, to determine the true economic feasibility of each dietary supplement.

Conversely, insect-based additives, such as meal-worm or black soldier fly larvae, while boasting a high protein and lipid content, currently command premium prices due to the nascent stage of industrial-scale production (Brown et al., 2021) (Table 2). The capital expenditure for establishing insect farms, including infrastructure, feed inputs, and energy consumption, contributes to the elevated cost. However, as production technologies advance and economies of scale are realized, a downward trend in prices is anticipated. Moreover, the environmental benefits of insect farming, such as reduced land use and greenhouse gas emissions, may factor into future economic models, potentially offsetting initial higher costs through carbon credits or regulatory incentives.

While byproducts often present the most economically advantageous option due to their inherent low cost and potential for local sourcing, the variability in processing and availability significantly influences their final price. Conversely, insect-based additives, despite their promising nutritional profile, currently exhibit higher costs associated with production scaling and processing (Sogari et al., 2023; Lisboa et al., 2024).

The utilization of agricultural and industrial byproducts in poultry feed formulations presents an economically compelling strategy for producers, primarily driven by their reduced acquisition costs and potential for localized sourcing (Table 3). However, the inherent variability in byproduct processing methods, coupled with fluctuations in seasonal availability, introduces significant price volatility (Williams et al., 2018; Georganas et al., 2023). This heterogeneity in processing can lead to inconsistencies in nutrient composition and digestibility, thereby necessitating rigorous quality control measures and precise ration adjustments (Campos et al., 2020). Consequently, while byproducts offer a cost-effective alternative, their economic advantage is intrinsically linked to the producer’s ability to navigate the challenges associated with their variable nature and ensure consistent nutritional delivery.

Ultimately, a comprehensive cost comparison must extend beyond initial procurement costs to encompass long-term impacts on poultry productivity, feed conversion efficiency, disease resistance, and environmental sustainability. Life cycle assessment and techno-economic analysis are essential tools for evaluating the true economic feasibility of these dietary supplements, providing a holistic perspective on their integration into poultry production systems.

The future of poultry nutrition holds promising advancements that are poised to revolutionize the industry. With the growing demand for high-quality and sustainable animal products, researchers are continuously exploring new ways to optimize poultry diets for improved performance and health. One of the prominent trends in poultry nutrition is the emphasis on precision feeding, where diets are tailored to meet the specific nutrient requirements of individual birds. This approach not only enhances feed efficiency and growth rates but also reduces nutrient wastage and environmental impacts. Additionally, the integration of novel ingredients and feed additives into poultry diets is an area of active research in the field of nutrition (Vlaicu et al., 2023; El-Sabrout et al., 2024). With the increasing concern over antibiotic resistance and the ban on in-feed antibiotics in many countries, there is a growing interest in alternative strategies to promote gut health and prevent disease in poultry. Probiotics, prebiotics, enzymes, and plant extracts are among the additives being explored for their potential to improve nutrient utilization, immune function, and overall performance in poultry. Incorporating these ingredients into feed formulations may offer a sustainable solution to support the health and welfare of birds while reducing the reliance on traditional antibiotics.

Advancements in technology, such as precision farming, genomics, and metabolomics, are expected to play a significant role in shaping the future of poultry nutrition. These tools can provide valuable insights into the interactions between diet, genetics, gut microbiota, and overall bird physiology, enabling more targeted and efficient strategies for optimizing feed formulations. Advancements in genomics and metabolomics, for example, have revolutionized the poultry industry by providing valuable insights into the genetic makeup and metabolic processes of poultry, offering unprecedented insights into biological processes and driving improvements in efficiency, health, and product quality (Zhang et al., 2024; Wadood and Zhang, 2024). Genomics refers to the study of an organism’s complete set of genes, while metabolomics focuses on the study of small molecules that are involved in various biochemical pathways within an organism. These cutting-edge technologies have enabled researchers to identify key genetic markers associated with desirable traits in poultry, such as improved growth rates, disease resistance, and meat quality. By analyzing the metabolic profiles of poultry, scientists can also gain a deeper understanding of the biochemical pathways that regulate important biological processes, ultimately leading to the development of more efficient and sustainable breeding programs. For example, genome-wide association studies (GWAS) have pinpointed genetic variants linked to enhanced feed efficiency, a crucial factor in sustainable poultry production (Ye et al., 2025). Complementarily, metabolomics provides a comprehensive profile of small molecules within biological systems, revealing metabolic pathways and biomarkers that reflect physiological states (Ren et al., 2024). By identifying genetic markers associated with desirable traits, breeders can more effectively select those traits in breeding populations, leading to faster and more efficient genetic improvement. Additionally, the use of metabolomics can help identify biomarkers for specific physiological processes, such as nutrient utilization and disease resistance, which can inform management practices and improve overall flock health and productivity. Furthermore, these technologies have the potential to enhance breeding strategies aimed at developing poultry breeds that are better adapted to changing environmental conditions, such as climate change and disease outbreaks (Nawaz et al., 2024; Zhang et al., 2024). The integration of genomic and metabolomic data provides a holistic understanding of poultry biology, paving the way for precision livestock farming and the development of tailored management strategies (Wadood and Zhang 2024).

By harnessing the power of data analytics and artificial intelligence, nutritionists can develop personalized diets that not only meet the nutritional needs of birds but also promote their well-being and performance. Overall, the future of poultry nutrition is bright, with exciting opportunities for innovation and sustainable practices that will enhance the efficiency and profitability of poultry production. It is well known that the poultry industry is undergoing rapid advancements driven by the growing global demand for sustainable and efficient production (Tiboldo et al., 2024). Therefore, nutrition plays a pivotal role in this progress, with innovative strategies being developed to enhance both poultry health and productivity (Korver, 2023). For example, using nanoparticles to deliver essential nutrients like vitamins and minerals can improve their bioavailability and absorption (Ahmad et al., 2022); providing specific amino acids that have functions beyond basic protein synthesis (Fathima et al., 2024); additionally, adding essential oils from oregano, thyme, and garlic to improve poultry gut health and reduce the need for antibiotics (El-Sabrout et al., 2023 b; Fotou et al., 2024).

In the future, poultry nutrition, particularly for broilers, will require significant changes. Traditionally, nutritionists have been tasked with reducing production costs by formulating low-cost diets that ensure optimal performance. However, modern society increasingly demands greater transparency regarding how animals are raised and fed. Recent years have witnessed the integration of cutting-edge technologies into feeding strategies, unlocking new possibilities to address some of the most pressing challenges in the poultry sector.

Embryonic development accounts for over 33% of the total lifespan of commercial broiler lines, highlighting its critical importance in poultry production (Givisiez et al., 2020). Disruptions during this stage can profoundly affect the entire production cycle, leading to irreversible losses for producers. Furthermore, more than half of a chicken’s productive lifespan is determined by conditions experienced during the incubation and post-hatch periods (Ayalew et al., 2023; Fares et al., 2023). Notably, the period from the 18th day of incubation to four days post-hatch is crucial for intestinal development (Iji et al., 2001) and plays a pivotal role in ensuring chick survival and optimal growth (Vieira and Moran, 1999; Uni and Ferket, 2004). During this critical window, chicks undergo significant metabolic and physiological changes as they transition from endogenous nutrient reserves to exogenous feed (De Oliveira et al., 2008; Givisiez et al., 2020). This shift imposes substantial energy and nutrient demands, and any imbalance or malnutrition during this phase can result in developmental deficits (Kadam et al., 2013; Ghanaatparast-Rashti et al., 2018). These deficits may impair embryonic development, hinder post-hatch growth performance (Ding et al., 2024), and delay the maturation of the intestinal tract (Geyra et al., 2001; Gao et al., 2017). To address these challenges, innovative practices such as in ovo feeding have been explored. This technique involves administering nutrients, additives, and bioactive substances directly into the egg during embryonic development to support pre- and post-hatch growth (Uni and Ferket, 2003; Uni et al., 2005). The timing of the injection is critical and varies based on the target compounds: injections are typically performed around day 14 of incubation for carbohydrates, hormones, and similar substances, or between days 17 and 18 for probiotics, vitamins, amino acids, and other compounds. Delivery methods often involve injection into the air sac or the amniotic fluid (Das et al., 2021).

Numerous studies have demonstrated the positive effects of in ovo feeding on the morphological and functional development of the intestinal mucosa (Gao et al., 2018; Jha et al., 2019; Givisiez et al., 2020). This technique has been shown to enhance post-hatch intestinal development in broilers (Wang et al., 2020), turkeys (Salmanzadeh et al., 2015), and quails (Kermanshahi et al., 2017). Practically all classes of nutritional additives can be employed in this technique, ranging from vitamins (Hajati et al., 2014) and phytobiotics (Akosile et al., 2023) to nanoparticles (Gao et al., 2017). For instance, in ovo delivery of amino acids, vitamins, and minerals has been shown to improve hatchability, chick weight, and feed conversion ratio (FCR; Bello et al., 2013; Li et al., 2016). N’nanle et al. (2017) reported that in ovo administration of Moringa oleifera extract improved hatchability and produced heavier chicks at hatch. Similarly, Ngueda et al. (2021) found that injecting Manihot esculenta extract on the 18th day of incubation not only improved hatchability but also shortened the total incubation duration.

Interestingly, some molecules have unexpected effects. For example, Fazli et al. (2015) found that garlic and tomato extracts increased the percentage of male chicks. Future hatchery facilities will not merely serve as sites for egg incubation and chick vaccination but will evolve into centers where chicks are programmed to better tolerate life challenges and achieve optimal feed efficiency.

A key focus area in this shift is the development of sustainable feed formulations and the application of emerging technologies, such as nanotechnology, to optimize nutrition and performance (Alanazi et al., 2024; Evci, 2024). Nanoparticles are innovative, nano-sized material structures with dimensions typically ranging from 1 to 100 nm in at least one direction (Ahmad et al., 2022). Due to their unique physicochemical properties, such as a high surface area-to-volume ratio and enhanced bioavailability (Gatoo et al., 2014), nanoparticles are increasingly explored to address critical challenges in poultry farming. Their application in poultry feed has gained considerable attention for improving nutrient absorption and optimizing the utilization of feed components that are otherwise poorly digested or excreted without fully retaining essential vitamins and minerals (Gangadoo et al., 2016). Nanoparticles also serve as versatile tools for nutrient delivery, antimicrobial action, and immune modulation (Hassan et al., 2020). The high surface area and superior absorption capacity of nanoparticles make them ideal platforms for integrating diverse compounds, including vaccines and nutrient supplements (Abd El-Ghany, 2019). These properties enable targeted delivery of compounds to specific organs or systems, reducing degradation often observed with conventional antibiotics, and thus offering multiple benefits (Mohan and Mala, 2019). For instance, supplementation with nano-zinc has been shown to enhance growth performance in broilers (Mohammadi et al., 2015). Zhou and Wang (2011) observed that nano-selenium supplementation enhanced final body weight, daily weight gain, feed conversion ratios, survival rates, and meat quality. Similarly, nano-silver and nano-selenium supplementation have been demonstrated to mitigate oxidative stress due to their potent antioxidant properties (Ahmadi and Kurdestani, 2010; Aparna and Karunakaran, 2016). Copper nanoparticles not only improve growth performance but also strengthen immune responses in poultry (Wang et al., 2011). Likewise, nano-iron supplementation has been reported to improve both growth performance and hatchability (Saki et al., 2014; Sizova et al., 2015). A key application in poultry nutrition is the use of nano-minerals, which demonstrate enhanced bioavailability and reduced antagonistic interactions in the gastrointestinal tract (Gopi et al., 2017). For these reasons, these additives address the limitations of traditional supplements, which often exhibit low bioavailability and contribute to environmental pollution through excessive excretion (Hu et al., 2012). Beyond nutritional benefits, nanoparticles serve as advanced delivery systems for bioactive compounds, such as vaccines, probiotics, and antioxidants (Suliman et al., 2023; Abdel-Raheem et al., 2024). Encapsulation within nanoparticles protects these compounds from gastrointestinal degradation, enabling targeted delivery and improved efficacy (Ahmad et al., 2022). However, their use requires precise management to prevent toxicity and disturbances in trace mineral balance (Evci, 2024). Despite their promising applications, the adoption of nanoparticles in poultry feed faces challenges related to safety and regulation. High concentrations of metal-based nanoparticles have been linked to oxidative stress, tissue damage, and immune disturbances, emphasizing the need for optimized dosing strategies and comprehensive safety evaluations (Min et al., 2023). The regulatory landscape for nanoparticle use in poultry feed is still underdeveloped, necessitating standardized protocols for characterization, safety assessments, and monitoring (More et al., 2021). Transparent communication and robust scientific evidence are essential to addressing consumer concerns, fostering trust, and promoting acceptance of nanoparticle use in animal products. Future research should prioritize the long-term effects of nanoparticles on poultry health, productivity, and environmental sustainability. Additionally, understanding their interactions with gut microbiota and other feed additives will provide valuable insights into their mechanisms of action and potential synergies.

Recent advancements in poultry nutrition have focused on exploring novel feed additives to enhance bird health, performance, and sustainability. The incorporation of phytogenics, fermented ingredients, bee products, insect additives, and byproducts from food processing industries presents promising avenues for improving feed efficiency, modulating gut microbiota, and enhancing immune function. These alternative feed sources offer a potential reduction in reliance on antibiotics and contribute to more sustainable and environmentally friendly poultry production systems. Furthermore, advancements in genomics, metabolomics, and data analytics will enable the development of precision nutrition strategies tailored to individual birds or flocks, optimizing feed formulations for specific needs and maximizing performance.

In summary, the key findings of this review are as follows:

• The reviewed dietary supplements (phytogenics, fermented ingredients, bee products, insect additives, and byproducts) demonstrate significant potential to enhance poultry production, health, and product quality.

• While promising, a deeper understanding of the precise mechanisms of action is crucial. This includes detailed investigations into their impact on gut microbiota modulation, immune responses, antioxidant pathways, and metabolic processes.

• Advanced omics technologies (genomics, proteomics, metabolomics) are essential to unravel the complex interactions between these supplements and poultry physiology.

• Variability in the composition and efficacy of these supplements necessitates rigorous standardization and quality control measures.

• Establishing standardized protocols for extraction, processing, and analysis is essential to ensure consistent and reproducible results.

• Utilizing byproducts and insect additives aligns with sustainable agricultural practices and the principles of a circular economy.

• Quality control of the products needs to be studied, to ensure that the products are free of contaminants.

• Assessing the economic viability and scalability of these supplements is critical for their widespread adoption in the poultry industry.

• The capacity of these supplements to enhance the poultry immune system offers a promising alternative to antibiotics.

• Future research should target the application of these supplements to address specific production challenges, such as heat stress, disease outbreaks, and suboptimal feed conversion ratios.