The Impact of P-biotics on the Future of Sustainable Poultry Production: A Systematic Review of Prebiotics, Probiotics, Postbiotics, and Synbiotics

Öz

Antimicrobial resistance linked to the long-term use of antibiotic growth promoters (AGPs) in poultry has intensified the search for effective, microbiome-based alternatives that can sustain performance without compromising food safety or animal welfare. This article aims to evaluate how recent advances in p-biotics (pre-, pro-, post-, and synbiotics) are shaping the future of sustainable poultry production. To achieve this, a systematic review was conducted using studies published between 2020 and 2025 on broilers and layers from literature databases such as Web of Science, Scopus, Google Scholar, and ScienceDirect. The PRISMA method was adopted, where 39 articles met the criteria for this review article after several exclusion criteria. The review shows that p-biotics consistently modulate gut microbiota, reinforce intestinal integrity, and enhance immune competence. Notably, the data reveal a consistent 10% to 15% improvement in feed conversion ratios and body weight gain under optimized probiotic and synbiotic regimens, directly addressing the production drops typically seen after antibiotic withdrawal. Probiotics and synbiotics, particularly Bacillus and Lactobacillus based formulations and oligosaccharide containing combinations, promote beneficial microbial populations, suppress enteric pathogens, and, in several studies, improve meat or egg quality and reduce dependence on AGPs. Postbiotic preparations from inactivated bacterial and yeast sources deliver comparable health and performance benefits while lowering the risk associated with live cultures. Evidence also indicates that p-biotics can lessen environmental burden by improving nutrient utilization and reducing nitrogen and phosphorus excretion, aligning poultry systems with broader sustainability targets. Nonetheless, considerable heterogeneity in strains, dosages, delivery routes, and experimental designs limits cross study comparability and hinders the development of standardized, context specific recommendations. Moving forward, research priorities must focus on conducting strain-specific field trials to validate efficacy across different poultry types, establishing standardized dosage protocols optimized for distinct commercial feeding phases (starter, grower, and finisher), and investigating the stability and viability of these p-biotics during high-temperature feed pelleting processes.

Anahtar Kelimeler

• P‑biotics
• Probiotics
• Prebiotics
• Postbiotics
• Synbiotics
• Antimicrobial resistance

Sürdürülebilir Tavukçulukta P-Biyotiklerin Geleceğe Etkisi: Sistematik Bir İnceleme

Öz

Uzun vadeli antibiyotik büyüme destekleyici (AGP) kullanımıyla bağlantılı antimikrobiyal direnç, performansı sürdürebilen ve gıda güvenliğini veya hayvan refahını riske atmayan etkili, mikrobiyom tabanlı alternatiflerin araştırılmasını artırdı. Bu makalenin amacı, son dönemde prebiyotik, probiyotik, postbiyotik ve simbiyotiklerdeki gelişmelerin sürdürülebilir tavukçuluk üretiminin geleceğini nasıl şekillendirdiğini değerlendirmektir. Bunu başarmak için 2020-2025 yılları arasında broiler ve yumurtacı tavuklar üzerinde yayınlanan çalışmalar, Web of Science, Scopus, Google Scholar ve ScienceDirect gibi literatür veritabanları kullanılarak sistematik bir şekilde incelenmiştir. PRISMA yöntemi benimsendi ve birkaç eleme kriterinin ardından, bu derleme makalesi için 39 makale kriterleri karşılandı. Derleme, probiyotiklerin bağırsak mikrobiyotasını sürekli olarak düzenlediğini, bağırsak bütünlüğünü güçlendirdiğini ve bağışıklık yetkinliğini artırdığını göstermektedir. Özellikle veriler, optimize edilmiş probiyotik ve sinbiyotik rejimlerinde yem dönüşüm oranlarında ve vücut ağırlığı artışında %10 ila %15 arasında tutarlı bir iyileşme olduğunu ortaya koyup; bu, genellikle antibiyotik kesildikten sonra görülen üretim düşüşlerini doğrudan ele almaktadır. Probiyotikler ve sinbiyotikler, özellikle Bacillus ve Lactobacillus bazlı formülasyonlar ile oligosakkarit içeren kombinasyonlar, faydalı mikrobiyal popülasyonları destekler, bağırsak patojenlerini baskılar ve birkaç çalışmada et veya yumurta kalitesini artırır ve AGP'lere olan bağımlılığı azaltır. İnaktifleşmiş bakteri ve maya kaynaklarından elde edilen postbiyotik preparatlar, canlı kültürlerle ilişkili riskleri azaltırken benzer sağlık ve performans faydaları sunmaktadır. Araştırmalar ayrıca, p-biyotiklerin besin kullanımını artırıp azot ve fosfor atılımını azaltarak çevresel yükü hafifletebileceğini ve böylece tavukçuluk sistemlerini daha geniş sürdürülebilirlik hedefleriyle uyumlu hale getirebileceğini göstermektedir. Yine de, suşlar, dozlar, uygulama yolları ve deney tasarımlarındaki büyük çeşitlilik, çalışmalar arası karşılaştırmayı zorlaştırıp standart, bağlama özel önerilerin geliştirilmesini engellemektedir. Makale, p-biyotiklerin antibiyotik içermeyen, sürdürülebilir tavuk üretimi için hayati bir araç olduğunu belirtiyor ve gelecekteki çalışmalar için öncelikleri ortaya koymaktadır.

Anahtar Kelimeler

• P‑biyotikler
• Probiyotikler
• Prebiyotikler
• Postbiyotikler
• Sinybiyotikler
• Antimikrobiyal direnç

Kaynakça

1. Abd El-Ghany, W. A., Fouad, H., Quesnell, R., & Sakai, L. (2022). The effect of a postbiotic produced by stabilized non-viable Lactobacilli on the health, growth performance, immunity, and gut status of colisepticaemic broiler chickens. Tropical animal health and production, 54(5), 286. https://doi.org/10.1007/s11250-022-03300-w
2. Abdel Aziz, A. M., G. M. Ali, N., Abdel Aziz, M. A. M., & El-Moghazy, G. M. (2018). Using Feed Additives For Better Utilizatıon Of Phosphorus And Nitrogen In Broilers Feeds. Journal of Environmental Science, 44(2), 61-80. doi: 10.21608/jes.2018.35499
3. Agyare, C., Etsiapa Boamah, V., Ngofi Zumbi, C., & Boateng Osei, F. (2018). Antibiotic Use in Poultry Production and Its Effects on Bacterial Resistance. In Antimicrobial Resistance - A Global Threat. IntechOpen. https://doi.org/10.5772/intechopen.79371
4. Ahiwe, E. U., Abdallh, M. E., Chang'a, E. P., Al-Qahtani, M., Omede, A. A., Graham, H., & Iji, P. A. (2019). Influence of autolyzed whole yeast and yeast components on broiler chickens challenged with salmonella lipopolysaccharide. Poultry science, 98(12), 7129–7138. https://doi.org/10.3382/ps/pez452
5. Ahmad, R., Yu, Y., Hsiao, F. S., Dybus, A., Ali, I., Hsu, H.-C., & Cheng, Y.-H. (2022). Probiotics as a Friendly Antibiotic Alternative: Assessment of Their Effects on the Health and Productive Performance of Poultry. Fermentation. https://doi.org/10.3390/fermentation8120672
6. Ali, P., Khan, S., Al-Khalaifah, H., Rafiullah, Khan, R. U., Naz, S., Alhidary, I. A., & Abudabos, A. (2025). Lactobacillus-Enriched Zophobas morio Larvae Impact Performance, Digestibility, Immunity and Economics in Broilers. Journal of animal physiology and animal nutrition, 109(5), 1192–1201. https://doi.org/10.1111/jpn.14131
7. Alowo, D., Olum, S., Mukisa, I. M., & Ongeng, D. (2025). Effect of thermal and non-thermal processing on fermentable oligo-di-monosaccharides and polyols (fodmaps) content in millet, sorghum, soybean and sesame varieties. Frontiers in Nutrition, 12. https://doi.org/10.3389/fnut.2025.1520510
8. Cai, Y., Xiao, C., Tian, B., Dorthe, S., Meuter, A., Song, B., & Song, Z. (2024). Dietary probiotic based on a dual-strain Bacillus subtilis improves immunity, intestinal health, and growth performance of broiler chickens. Journal of animal science, 102, skae183. https://doi.org/10.1093/jas/skae183

9. Casewell, M., Friis, C., Marco, E., McMullin, P., & Phillips, I. (2003). The European ban on growth-promoting antibiotics and emerging consequences for human and animal health. The Journal of antimicrobial chemotherapy, 52(2), 159–161. https://doi.org/10.1093/jac/dkg313
10. Chowdhury, R., Islam, K. M., Khan M. J.M., Karim, M. R., Haque, M. N., Khatun, M and Pesti, G.M. (2009). Effect of citric acid, avilamycin, and their combinations on the performance, tibia ash, and immune status of broilers. Poultry Science, 88: 1616-1622
11. Das, R., Mishra, P., Mishra, B., & Jha, R. (2024). Effect of in ovo feeding of xylobiose and xylotriose on plasma immunoglobulin, cecal metabolites production, microbial ecology, and metabolic pathways in broiler chickens. Journal of Animal Science and Biotechnology, 15(1). https://doi.org/10.1186/s40104-024-01022-7
12. de Jong, A., Simjee, S., Garch, F. E., Moyaert, H., Rose, M., Youala, M., Dry, M., & EASSA Study Group (2018). Antimicrobial susceptibility of enterococci recovered from healthy cattle, pigs and chickens in nine EU countries (EASSA Study) to critically important antibiotics. Veterinary microbiology, 216, 168–175. https://doi.org/10.1016/j.vetmic.2018.02.010
13. Desak, P., Mas, A., Mahardika, G., Nyoman, G., Bidura, G., & Ni, W. (2023). The effect of adding synbiotics between Moringa and Yeast (MYS) in feed on growth and feed efficiency in starter phase broilers. World Journal of Biology Pharmacy and Health Sciences, 16(1). https://doi.org/10.30574/wjbphs.2023.16.1.0409
14. Drauch, V., Ghanbari, M., Reisinger, N., Mohnl, M., Hess, C., & Hess, M. (2025). Differential effects of synbiotic delivery route (feed, water, combined) in broilers challenged with Salmonella Infantis. Poultry science, 104(4), 104890. https://doi.org/10.1016/j.psj.2025.104890
15. Founou, L. L., Founou, R. C., & Essack, S. Y. (2021). Antimicrobial resistance in the farm-to-plate continuum: more than a food safety issue. Future science OA, 7(5), FSO692. https://doi.org/10.2144/fsoa-2020-0189D
16. Gao, C., Shi, H., Xie, W., Zhao, L., Zhang, J., Ji, C., & Ma, Q. (2021). Dietary Supplementation with Acidifiers Improves the Growth Performance, Meat Quality and Intestinal Health of Broiler Chickens. Animal Nutrition. https://doi.org/10.1016/j.aninu.2021.01.005
17. Gibson, G. R., Probert, H. M., van Loo, J. A. E., Rastall, R. A. Roberfroid, M. B. 2004. Dietary modulation of the human colonic microbiota: updating the concept of prebiotics. Nutrition Research Reviews, 17: 259-275
18. Gilad, O., Svensson, B., Viborg, A. H., Stuer-Lauridsen, B., & Jacobsen, S. (2011). The extracellular proteome of Bifidobacterium animalis subsp. lactis BB-12 reveals proteins with putative roles in probiotic effects. Proteomics, 11(12), 2503–2514. https://doi.org/10.1002/pmic.201000716
19. Gingerich, E., Frana, T., Logue, C. M., Smith, D. P., Pavlidis, H. O., & Chaney, W. E. (2021). Effect of Feeding a Postbiotic Derived from Saccharomyces cerevisiae Fermentation as a Preharvest Food Safety Hurdle for Reducing Salmonella Enteritidis in the Ceca of Layer Pullets. Journal of food protection, 84(2), 275–280. https://doi.org/10.4315/JFP-20-330
20. Gopal, B., Tattimani, S., Kelkar, V., & Gopal, S. (2024). A novel formulation of synbiotics fortified with phytoactives for augmentation of performance, meat and litter quality, health, gut health and gut microflora in broiler chickens. Indian Journal of Animal Research, (Of). https://doi.org/10.18805/ijar.b-5201
21. Hamprakorn, K., Maneewan, B., Jantasin, W., Lani, M. N., Moonmanee, T., & Panatuk, J. (2025). Effect of extracted phycocyanin by-products as a synbiotic supplement on the production performance and intestinal morphology of broilers. Veterinary world, 18(1), 52–59. https://doi.org/10.14202/vetworld.2025.52-59
22. Han, H., Fu, L., Wang, J., Sun, Y., Cao, D., Lei, Q., Zhou, Y., Li, F., Liu, W., Li, D., Hao, D., & Liu, J. (2025). Effect of dietary supplementation with Brevibacillus laterosporus on broiler growth performance, meat quality and gut microbiome. Frontiers in microbiology, 16, 1608076. https://doi.org/10.3389/fmicb.2025.1608076
23. Hudson, J., Frewer, L., Jones, G., Brereton, P., Whittingham, M., & Stewart, G. (2017). The agri-food chain and antimicrobial resistance: A review. Trends in Food Science and Technology, 69(part A), 131-147. Article 69. https://doi.org/10.1016/j.tifs.2017.09.007
24. Ibrahim, M., Bednarczyk, M., Stadnicka, K., & Grochowska, E. (2025). Inter- and transgenerational effects of in ovo stimulation with bioactive compounds on cecal tonsils and cecal mucosa transcriptomes in a chicken model. International Journal of Molecular Sciences, 26(3), 1174. https://doi.org/10.3390/ijms26031174
25. Jeni, R. El, Dittoe, D. K., Olson, E. G., Lourenço, J. M., Corcionivoschi, N., Ricke, S. C., & Callaway, T. R. (2021). Probiotics and Potential Applications for Alternative Poultry Production Systems. Poultry Science. https://doi.org/10.1016/j.psj.2021.101156
26. Kaur, A. P., Bhardwaj, S., Dhanjal, D. S., Nepovimova, E., Cruz-Martins, N., Kuča, K., Chopra, C., Singh, R., Kumar, H., Șen, F., Kumar, V., Verma, R., & Kumar, D. (2021). Plant Prebiotics and Their Role in the Amelioration of Diseases. Biomolecules, 11(3), 440. https://doi.org/10.3390/biom11030440
27. Khan, S., Sattar, A., Lodhi, S., Abbas, A., Ali, F., Rahman, S. & Naveed, M. (2023). Individual and combined efficacy of antibiotics and probiotics on the growth of broiler chicken. PJMHS, 17(2), 698-702. https://doi.org/10.53350/pjmhs2023172698
28. Khosravi, A., Boldaji, F., & Dastar, B. (2025). A synbiotic improves performance and gut health in broiler chickens. Scientific Reports, 15, 19164. https://doi.org/10.1038/s41598-025-04459-6
29. Kiernan, D. P., O’Doherty, J. V., & Sweeney, T. (2023). The Effect of Prebiotic Supplements on the Gastrointestinal Microbiota and Associated Health Parameters in Pigs. Animals, 13(19), 3012. https://doi.org/10.3390/ani13193012
30. Kim, G., Seo, Y., Kim, C., & Paik, I. (2011). Effect of dietary prebiotic supplementation on the performance, intestinal microflora, and immune response of broilers. Poultry Science, 90(1), 75-82. https://doi.org/10.3382/ps.2010-00732
31. Lee, J. Y., Tsolis, R. M., & Bäumler, A. J. (2022). The microbiome and gut homeostasis. Science (New York, N.Y.), 377(6601), eabp9960. https://doi.org/10.1126/science.abp9960
32. Li, X., Liu, Y., Weng, S., Chen, W., Gao, J., Cheng, P., & Tang, W. (2025). Phenotypic and genomic analyses of the probiotic enterococcus casseliflavus shamu-qh-02. Frontiers in Microbiology, 16. https://doi.org/10.3389/fmicb.2025.1535506
33. Maria Cardinal, K., Kipper, M., Andretta, I., & Machado Leal Ribeiro, A. (2019). Withdrawal of antibiotic growth promoters from broiler diets: performance indexes and economic impact. Poultry science, 98(12), 6659–6667. https://doi.org/10.3382/ps/pez536
34. Melara, E. G., Avellaneda, M. C., Aroche, R., & Martínez, Y. (2026). Effect of Oral Supplementation with Lactobacillus reuteri CLP4 on Growth Performance, Carcass Traits, Organ Weights, Cecal Microbiology, Tibial Mineralization, Blood Indicators and Nitrogen and Phosphorus Excretion in Broilers. Preprints. https://doi.org/10.20944/preprints202603.1242.v1
35. Muhammad S. S and Muhammad K. H (2023). The role of probiotics in animal nutrition and health. World Journal of Advanced Research and Reviews. 17. 276-280. 10.30574/wjarr.2023.17.3.0396.
36. Obianwuna, U. E., Xin, P., Xin, C., Zhang, H., Qiu, K., Wang, J., Zhou, J., & Wu, S. (2025). XOS-based prebiotic complex improves laying performance and attenuates inflammation-driven gut injury and dysbiosis under LPS challenge. Poultry science, 105(1), 106124. https://doi.org/10.1016/j.psj.2025.106124
37. Page, M. J., McKenzie, J. E., Bossuyt, P. M., Boutron, I., Hoffmann, T. C., Mulrow, C. D., Shamseer, L., Tetzlaff, J. M., Akl, E. A., Brennan, S. E., Chou, R., Glanville, J., Grimshaw, J. M., Hróbjartsson, A., Lalu, M. M., Li, T., Loder, E. W., Mayo- Wilson, E., McDonald, S., McGuinness, L. A., … Moher, D. (2021). The PRISMA 2020 statement: An updated guideline for reporting systematic reviews. International journal of surgery (London, England), 88, 105906. https://doi.org/10.1016/j.ijsu.2021.105906
38. Pewan, S. B., Kabantiyok, D., Emennaa, P. E., Dawurung, J., Dawurung, C. J., Olorundare, O. O., Umaru, M. G., Ugwuoke, G. M., & Ezema, C. (2025). Advancing Nigerian Indigenous Poultry Health and Production, Use of Probiotics as Viable Alternatives to Antibiotics: A Review. Antibiotics. https://doi.org/10.3390/antibiotics14080846
39. Pham, V. H., Kan, L., Huang, J., Geng, Y., Zhen, W., Guo, Y., Abbas, W., & Wang, Z. (2020). Dietary encapsulated essential oils and organic acids mixture improves gut health in broiler chickens challenged with necrotic enteritis. Journal of animal science and biotechnology, 11, 18. https://doi.org/10.1186/s40104-019-0421-y
40. Puvača, N., Nikolić, S. R., & Muhović, A. (2021). Analysis of Economic Results of Dietary Medicinal Plants Usage in Broilers Production. Ekonomika Poljoprivrede. https://doi.org/10.5937/ekopolj2104977p
41. Rafiq, K., Hossain, M. T., Ahmed, R., Hasan, M. M., Islam, R., Hossen, M. I., Shaha, S. N., & Rume, F. I. (2022). Role of Different Growth Enhancers as an Alternative to in-Feed Antibiotics in the Poultry Industry. Frontiers in Veterinary Science. https://doi.org/10.3389/fvets.2021.794588
42. Richards, P. J., Almutrafy, A., Liang, L., Flaujac Lafontaine, G. M., King, E., Fish, N. M., Connerton, A. J., Connerton, P. L., & Connerton, I. F. (2024). Prebiotic galactooligosaccharide feed modifies the chicken gut microbiota to efficiently clear Salmonella. mSystems, 9(8), e0075424. https://doi.org/10.1128/msystems.00754-24
43. Rodrigues, G., Souza Santos, L., & Franco, O. L. (2022). Antimicrobial Peptides Controlling Resistant Bacteria in Animal Production. Frontiers in microbiology, 13, 874153. https://doi.org/10.3389/fmicb.2022.874153
44. Saeed, M., Afzal, Z., Afzal, F., Khan, R. U., Elnesr, S. S., Alagawany, M., & Chen, H. (2023). Use of Postbiotic as Growth Promoter in Poultry Industry: A Review of Current Knowledge and Future Prospects. Food science of animal resources, 43(6), 1111–1127. https://doi.org/10.5851/kosfa.2023.e52
45. Salminen, S., Collado, M. C., Endo, A., Hill, C., Lebeer, S., Quigley, E. M. M., Sanders, M. E., Shamir, R., Swann, J. R., Szajewska, H., & Vinderola, G. (2021). The International Scientific Association of Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of postbiotics. Nature reviews. Gastroenterology & hepatology, 18(9), 649–667. https://doi.org/10.1038/s41575-021-00440-6
46. Szczypka, M., Suszko-Pawłowska, A., Kuczkowski, M., Gorczykowski, M., Lis, M., Kowalczyk, A., … & Stefaniak, T. (2021). Effects of selected prebiotics or synbiotics administered in ovo on lymphocyte subsets in bursa of the fabricius, thymus, and spleen in non-immunized and immunized chicken broilers. Animals, 11(2), 476. https://doi.org/10.3390/ani11020476
47. Seikh, A., Mondal, S., Mandal, G. P., Roy, B., Mandal, S., Ghosh, P., & Soren, S. (2025). Comparative study of probiotics and postbiotics on growth performance, carcass traits, and blood biochemical profiles in broiler chickens. International Journal of Veterinary Science and Animal Husbandry, 10(10), 45–50. https://doi.org/10.22271/veterinary.2025.v10.i10a.2600
48. Selaledi, L., Hassan, Z. M., Manyelo, T. G., & Mabelebele, M. (2020). The Current Status of the Alternative Use to Antibiotics in Poultry Production: An African Perspective. Antibiotics. https://doi.org/10.3390/antibiotics9090594
49. Selim, S., Abdel-Megeid, N. S., Khalifa, H. K., Fakiha, K. G., Majrashi, K. A., & Hussein, E. (2022). Efficacy of Various Feed Additives on Performance, Nutrient Digestibility, Bone Quality, Blood Constituents, and Phosphorus Absorption and Utilization of Broiler Chickens Fed Low Phosphorus Diet. Animals, 12(14), 1742. https://doi.org/10.3390/ani12141742
50. Shah, S., Islam, M., Zabin, R., Roy, P., Meghla, N., & Jahid, I. (2021). Assessment of novel probiotic strains on growth, hematobiochemical parameters, and production costs of commercial broilers in bangladesh. Veterinary World, 14(1), 97-103. https://doi.org/10.14202/vetworld.2021.97-103
51. Šimunović, K., Sahin, O., Erega, A., Štefanič, P., Zhang, Q., Mandic Mulec, I., Smole Možina, S., & Klančnik, A. (2022). Bacillus subtilis PS-216 Spores Supplemented in Broiler Chicken Drinking Water Reduce Campylobacter jejuni Colonization and Increases Weight Gain. Frontiers in microbiology, 13, 910616. https://doi.org/10.3389/fmicb.2022.910616
52. Singh, A., Tiwari, U., Mishra, B., & Jha, R. (2022). Effects of in ovo delivered xylo- and mannan- oligosaccharides on growth performance, intestinal immunity, cecal short-chain fatty acids, and cecal microbiota of broilers. Journal of Animal Science and Biotechnology, 13(1). https://doi.org/10.1186/s40104-021-00666-z
53. Slawinska, A., Zampiga, M., Sirri, F., Meluzzi, A., Bertocchi, M., Tavaniello, S., & Maiorano, G. (2020). Impact of galactooligosaccharides delivered in ovo on mitigating negative effects of heat stress on performance and welfare of broilers. Poultry science, 99(1), 407–415. https://doi.org/10.3382/ps/pez512
54. Śliżewska, K., Markowiak-Kopeć, P., Sip, A., Lipiński, K., & Mazur-Kuśnirek, M. (2020). The Effect of Using New Synbiotics on the Turkey Performance, the Intestinal Microbiota and the Fecal Enzymes Activity in Turkeys Fed Ochratoxin A Contaminated Feed. Toxins, 12(9), 578. https://doi.org/10.3390/toxins12090578
55. Soren, S., Mandal, G. P., Mondal, S., Pradhan, S., Mukherjee, J., Banerjee, D., Pakhira, M. C., Amla, Mondal, A., Nsereko, V., & Samanta, I. (2024). Efficacy of Saccharomyces cerevisiae Fermentation Product and Probiotic Supplementation on Growth Performance, Gut Microflora and Immunity of Broiler Chickens. Animals: an open access journal from MDPI, 14(6), 866. https://doi.org/10.3390/ani14060866
56. Stokstad, E. L., & Jukes, T. H. (1949). The multiple nature of the animal protein factor. The Journal of biological chemistry, 180(2), 647–654.
57. Such, N., Mezőlaki, Á., Rawash, M. A., Tewelde, K. G., Pál, L., Wágner, L., Schermann, K., Poór, J., & Dublecz, K. (2023). Diet Composition and Using Probiotics or Symbiotics Can Modify the Urinary and Faecal Nitrogen Ratio of Broiler Chicken's Excreta and Also the Dynamics of In Vitro Ammonia Emission. Animals: an open access journal from MDPI, 13(3), 332. https://doi.org/10.3390/ani13030332
58. Sulaiman, A. S., Hussaini, B. A., & Uyanga, V. A. (2025). Effects of probiotics, prebiotics, and synbiotics on the growth performance, biochemical indexes, and gut morphometry of turkeys. Frontiers in physiology, 16, 1703083. https://doi.org/10.3389/fphys.2025.1703083
59. Szczypka, M., Suszko-Pawłowska, A., Kuczkowski, M., Gorczykowski, M., Lis, M., Kowalczyk, A., Łukaszewicz, E., Poradowski, D., Zbyryt, I., Bednarczyk, M., & Stefaniak, T. (2021). Effects of Selected Prebiotics or Synbiotics Administered in ovo on Lymphocyte Subsets in Bursa of the Fabricius, Thymus, and Spleen in Non-Immunized and Immunized Chicken Broilers. Animals, 11(2), 476. https://doi.org/10.3390/ani11020476
60. Tomczyk, G., Niczyporuk, J., Kozdruń, W., Sawicka, A., Bocian, Ł., Barabasz, M., … & Michalski, M. (2024). Probiotic supplementation as an alternative to antibiotics in broiler chickens. Journal of Veterinary Research, 68(1), 147-154. https://doi.org/10.2478/jvetres-2024-0009
61. Van Saun R. J. (2014). Feeds for camelids, in: Cebre C, Anderson DE, Tibary A, Van Saun RJ, Johnson LW. (Eds), Llama and Alpaca Care Medicine, Surgery, Reproduction, Nutrition, and Herd Health. Elsevier Inc.
62. Watts S. A., and Lawrence J. M. (2020). Sea urchins: biology and ecology, in: Lawrence JM. (Ed), Developments in Aquaculture and Fisheries Science. Elsevier Inc
63. Wen, C., Yan, W., Mai, C., Duan, Z., Zheng, J., Sun, C., & Yang, N. (2021). Joint contributions of the gut microbiota and host genetics to feed efficiency in chickens. Microbiome, 9(1), 126. https://doi.org/10.1186/s40168-021-01040-x
64. Whitmore, M. A., Guo, J., Kim, D.-H., Liu, J., Tobin, I., & Zhang, G. (2025). Deoxycholic Acid Mitigates Necrotic Enteritis Through Selective Inhibition of Pathobionts and Enrichment of Specific Lactic Acid Bacteria. Pathogens. https://doi.org/10.3390/pathogens14070688
65. Wickramasuriya, S., Ault, J., Ritchie, S., Gay, C., & Lillehoj, H. (2024). Alternatives to antibiotic growth promoters for poultry: a bibliometric analysis of the research journals. Poultry Science, 103(9), 103987. https://doi.org/10.1016/j.psj.2024.103987
66. World Health Organization (2017). Antimicrobial Resistance: Global Report on Surveillance. World Health Organization. https://www.who.int/publications/i/item/B09585 (access date 03.06.2026)
67. Xu, Y., Yu, Y., Shen, Y., Li, Q., Lan, J., Wu, Y., & Yang, C. (2021). Effects of bacillus subtilis and bacillus licheniformis on growth performance, immunity, short chain fatty acid production, antioxidant capacity, and cecal microflora in broilers. Poultry Science, 100(9), 101358. https://doi.org/10.1016/j.psj.2021.101358
68. Xu, C., Wei, F., Yang, X., Feng, Y., Liu, D., & Hu, Y. (2022). Lactobacillus salivarius cml352 isolated from Chinese local breed chicken modulates the gut microbiota and improves intestinal health and egg quality in late-phase laying hens. Microorganisms, 10(4), 726. https://doi.org/10.3390/microorganisms10040726
69. Xu, H., Lu, Y., Li, D., Yan, C., Jiang, Y., Hu, Z., … & Wang, Y. (2023). Probiotic mediated intestinal microbiota and improved performance, egg quality and ovarian immune function of laying hens at different laying stage. Frontiers in Microbiology, 14. https://doi.org/10.3389/fmicb.2023.1041072
70. Xu, J., Li, M., Li, R., Zhang, Z., Ma, Y., Tao, R., Zou, L., Wang, J., Wen, L., & Li, R. (2025). Effect of Areca Nut Extracts on Growth Performance, Slaughtering Performance, and Meat Quality of Broiler Chickens. Frontiers in Veterinary Science. https://doi.org/10.3389/fvets.2025.1579415
71. Yue, T., Lu, Y., Ding, W., Xu, B., Zhang, C., Li, L., Jian, F., & Huang, S. (2025). The Role of Probiotics, Prebiotics, Synbiotics, and Postbiotics in Livestock and Poultry Gut Health: A Review. Metabolites, 15(7), 478. https://doi.org/10.3390/metabo15070478
72. Zammit, V. A., & Park, S. O. (2024). Effect of Dietary Housefly Maggot Extract on Egg Production and Egg Quality in Laying Hens Under a Digital Livestock System. Czech Journal of Animal Science. https://doi.org/10.17221/146/2023-cjas