Fecal Metabolite Biomarkers for Monitoring Gut Health and Enteric Diseases in Poultry: A Systematic Review
Abstract:
Monitoring gastrointestinal health is essential for maintaining productivity, improving disease resistance, and ensuring welfare in poultry production. Conventional diagnostic methods are often invasive, delayed, or lack sensitivity for detecting early-stage gut disorders. Fecal metabolite biomarkers offer a promising, non-invasive alternative for assessing gut health in real time. This systematic review evaluates the application of fecal metabolites in identifying enteric diseases and monitoring gut status in poultry, focusing on biomarker classes, disease links, and nutritional strategies. Relevant studies were retrieved from PubMed, Scopus, and Google Scholar, screened using PRISMA guidelines, and assessed with an adapted SYRCLE Risk of Bias tool. Ten studies met all eligibility criteria. Key metabolite groups short-chain fatty acids (particularly butyrate), histamine, amino acids, indole derivatives, and trehalose were associated with necrotic enteritis, coccidiosis, and gut dysbiosis. Nutritional interventions including inulin, resistant starch, Hermetia illucens meal, and citrus extract consistently improved metabolite profiles and intestinal integrity. Several biomarkers exhibited disease-specific patterns, suggesting diagnostic value. These findings highlight the potential of fecal metabolite biomarkers as practical tools for non-invasive gut health surveillance in poultry. Further research should focus on standardizing biomarker panels, establishing diagnostic thresholds, and integrating multi-omics approaches to enable their application in precision poultry health management.
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Bai, H., Shi, L., Guo, Q., Zou, J., Jiao, H., Wang, Y., & Chang, G. (2023). Metagenomic insights into the relationship between gut microbiota and residual feed intake of small-sized meat ducks. Frontiers in Microbiology, 13, 1-11. https://doi.org/10.3389/fmicb.2022.1075610
Bassols, A., Amigó, N., Pérez-Rodado, M., Tibau, J., & Martí, S. (2025). Metagenomic insights into the relationship between gut microbiota and residual feed intake of small-sized meat ducks. Frontiers in Microbiology, 13, 1-11. https://doi.org/10.3389/fmicb.2022.1075610
Brugaletta, G., Zappaterra, M., Mattioli, S., Sirri, F., & Meluzzi, A. (2020). Effect of alternative administration programs of a synbiotic supplemenet, foot pad dermatitis, cecal microbiota, and blood metabolites. Animals, 10(3), 522. https://doi.org/10.3390/ani10030522
Bucław, M. (2016). The use of inulin in poultry feeding: A review. Journal of Animal Physiology and Animal Nutrition, 100(6), 1015-1022. https://doi.org/10.1111/jpn.12484
Chen, L., Ding, H., Zhu, Y., Hu, S., Wang, S., Wang, R., Liu, X., Jin, S., Chen, Q., & Zhang, T. (2023). Untargeted and targeted metabolomics identify metabolite biomarkers for Salmonella enteritidis in chicken meat. Food Chemistry, 429, Article 136834. https://doi.org/10.1016/j.foodchem.2022.135294
Choi, S., & Kim, E. B. (2023). A comprehensive longitudinal study of gut microbiota dynamic changes in laying hens at four growth stages prior to egg production. Animal Bioscience, 36(4), 637–648. doi: 10.5713/ab.23.0271
Cisse, S., Matuszewski, A., Bień, D., Konieczka, P., Kozłowski, K., Rawski, M., ... & Benarbia, M. E. A. (2025). A comprehensive longitudinal study of gut microbiota dynamic changes in laying hens at four growth stages prior to egg production. Animal Bioscience, 36(4), 637–648. https://doi.org/10.3390/ani15020127
De Meyer, F., Eeckhaut, V., Ducatelle, R., Dhaenens, M., Daled, S., Dedeurwaerder, A., Van Denberghe, W., Deforce, D., & Van Immerseel, F. (2019). Host intestinal biomarker identification in a gut leakage model in broilers. Veterinary Research, 50, Article 46. https://doi.org/10.1186/s13567-019-0663-x
de Souza, M., Cicero, C. E., Menck-Costa, M. F., Oliveira, M. L. A. G., Correia, R. T. P., & Bracarense, A. P. F. R. L. (2021). Histological evaluation of the intestine of broiler chickens: Comparison of three sampling methods. Semina: Ciências Agrárias, 42(3), 1391–1400. https://doi.org/10.5433/1679-0359.2021v42n6p3247
Fathima, S., Al Hakeem, W. G., Shanmugasundaram, R., ... & Selvaraj, R. K. (2024). The effect of supplemental arginine on the gut microbial homeostasis of broilers during sub-clinical necrotic enteritis challenge. Frontiers in Physiology, 15, 1291836. https://doi.org/10.3389/fphys.2024.1291836
Santanilla F., E. B., Betancourt López, L. L., Contreras Rodríguez, L. E., & Granados Falla, D. S. (2024). Resistant starch from a tuberous root from the Andes cordillera improves metabolic and immune parameters in broilers. Bioactive Carbohydrates and Dietary Fibre, 31, 100372. https://doi.org/10.1016/j.bcdf.2024.100420
Gautam, H., Ahmad, S. N., Banaganapalli, B., Popowich, S., Chow-Lockerbie, B., Ayalew, L. E., Mandal, R., Wishart, D. S., Tikoo, S., & Gomis, S. (2025). Elevated butyric acid and histamine in feces and serum as an indicator of onset of necrotic enteritis in broiler chickens. Frontiers in Microbiology, 16, 1581309. https://doi.org/10.3389/fmicb.2025.1581309
Hartinger, K., Fröschl, K., Ebbing, M. A., Bruschek-Pfleger, B., Schedle, K., Schwarz, C., & Gierus, M. (2022). Suitability of Hermetia illucens larvae meal and fat in broiler diets: Effects on animal performance, apparent ileal digestibility, gut histology, and microbial metabolites. Journal of Animal Science and Biotechnology, 13, 50. https://doi.org/10.1186/s40104-022-00701-7
Karl, J. P., Armstrong, N. J., Player, R. A., McClung, H. L. (2022). The fecal metabolome links diet composition, food processing, and the gut microbiota to gastrointestinal health in a randomized trial of adults consuming a processed diet. Journal of Nutrition. https://doi.org/10.1093/jn/nxac161
Kayal, A., Yu, S. J., Van, T. T. H., Moore, R. J., & Stanley, D. (2025). Effect of early gut microbiota intervention using pre-designed poultry microbiota substitute on broiler health and performance. Animal Production Science, 65(1), 11–22. https://doi.org/10.1071/an24354
Khalili, L., & Amini, A. (2015). Resistant starch in food industry. In Polysaccharides: Bioactivity and Biotechnology, 2024-2056. Springer. DOI:10.1007/978-3-319-03751-6_42-1
Kozłowska, I., Marć-Pieńkowska, J., & Bednarczyk, M. (2016). Beneficial aspects of inulin supplementation as a fructooligosaccharide prebiotic in monogastric animal nutrition - A review. Annals of Animal Science, 16(4), 935-962. DOI: 10.1515/aoas-2015-0090
Liu, Y. S., Zhang, Y. Y., Li, J. L., Wang, T., & Gao, F. (2020). Growth performance, carcass traits and digestive function of broiler chickens fed diets with graded levels of corn resistant starch. British Poultry Science, 61(2), 146-155. https://doi.org/10.1080/00071668.2019.1694137
Ma, N., Zhao, Y., Wang, J., Li, Z., Tian, X., Zhang, P., ... & Wang, J. (2023). Inulin supplementation restores intestinal microbiota and gut barrier in three breeds of laying hens. Poultry Science, 102(2). 102266
Mon, K. K. Z., Zhu, Y., Chanthavixay, G., ... & Zhou, H. (2020). Integrative analysis of gut microbiome and metabolites revealed novel mechanisms of intestinal Salmonella carriage in chicken. Scientific Reports, 10, 10107. doi: 10.1038/s41598-020-60892-9
Montes-Vergara, D. E., Cardona-Alvarez, J., & Pérez-Cordero, A. (2021). Prevalence of gastrointestinal parasites in three groups of domestic poultry managed under backyard system in the Savanna subregion, Department of Sucre, Colombia. Journal of Advanced Veterinary and Animal Research, 8(1), 32–38. http://doi.org/10.5455/javar.2021.h551
Nam, S. L., Tarazona Carrillo, K., de la Mata, A. P., Harynuk, J. J. (2023). Untargeted metabolomic profiling of aqueous and lyophilized pooled human feces from two diet cohorts using two-dimensional gas chromatography coupled with time-of-flight mass spectrometry. Metabolites. https://doi.org/10.3390/metabo13070828
Naumova, N. B., Alikina, T. Y., Zolotova, N. S., Konev, A. V., Pleshakova, V. I., Lescheva, N. A., & Kabilov, M. R. (2021). Bacillus-based probiotic treatment modified bacteriobiome diversity in duck feces. Agriculture, 11(5), 406. https://doi.org/10.3390/agriculture11050406
Oluseyifunmi, A., Smith, O., Johnson, M., & Anderson, D. (2024). Role of resistant starch and dietary fiber in modulation of gut health biomarkers in broilers. Animal Nutrition, 10(1), 55–654.
Philip, D., Hodgkiss, R., Radhakrishnan, S. K., Acharjee, A. (2025). Deciphering microbial and metabolic influences in gastrointestinal diseases-unveiling their roles in gastric cancer, colorectal cancer, and inflammatory bowel disease. Journal of Translational Medicine. https://doi.org/10.1186/s12967-025-06552-w
Pires, P. G. D. S., Cardinal, K. M., Elnesr, S. S., Fraceto, L. F., de Castro, F. L. S., & Moraes, P. D. O. (2025). Non-invasive biomarkers for monitoring intestinal health in broilers – A systematic review. Research in Veterinary Science, 162, 209-223. https://doi.org/10.1016/j.rvsc.2025.105669
Rath, N. C., Gupta, A., Liyanage, R., & Lay, J. O. (2019). Phorbol 12-Myristate 13-Acetate-Induced Changes in Chicken Enterocytes. Proteomics Insights, 10, 1178641819851392 https://doi.org/10.1177/1178641819851392
Rysman, K., Eeckhaut, V., Ducatelle, R., & Van Immerseel, F. (2023). The fecal biomarker ovotransferrin associates with broiler performance under field conditions. Poultry Science, 102, Article 102585. DOI: 10.1016/j.psj.2023.103011
Salahi, A., Abd El-Ghany, W. A., Attia, Y. A., ... & Tufarelli, V. (2025). Gut dysbiosis: Nutritional causes and risk prevention in poultry, with reference to other animals. South African Journal of Animal Science, 55(1), 8–20.
Song, J., Li, Q., Everaert, N., Liu, R., Zheng, M., Zhao, G., ... & Wen, J. (2020). Dietary inulin supplementation modulates short-chain fatty acid levels and cecum microbiota composition and function in chickens infected with Salmonella. Frontiers in Microbiology, 11. https://doi.org/10.3389/fmicb.2020.584380
Susanti, R., Yuniastuti, A., & Fibriana, F. (2020). Metagenome analysis of gut microbial in both the caged and non-caged ducks. Journal of Physics: Conference Series, 1467, 012024.
Taleuzzaman, M., Anupam, Verma, M., Choudhary, R. (2025). Gut microbial metabolites as diagnostic biomarkers. Gut Microbiota and their Impact on Disease Pathways and Interventions. DOI: 10.2174/9789815324549125010012
Ul Saqib, N., Islam, Z., Sultan, A., Ahmad, S., Raziq, F., & Jan, A. U. (2025). Effect of dried orange (Citrus sinensis) pulp on growth performance, serum biochemical parameters, and nutrient digestibility in broiler chickens. Pakistan Journal of Zoology, 57(1), 123-132. DOI:10.17582/journal.pjz/20230803122156
Wang, S., Chen, L., He, M., Shen, J., Yin, J., Lu, L., & Wang, Y. (2018). Different rearing conditions alter gut microbiota composition and host physiology in Shaoxing ducks. Scientific Reports, 8, 7387. DOI: 10.1038/s41598-018-25760-7
Wang, Z., Shang, P., Song, X., Wu, M., Zhang, T., Zhao, Q., Zhu, S., Qiao, Y., Zhao, F., Zhang, R., Jinwen Wang, Yu, Y., Han, H., & Dong, H. (2024). Alterations in ileal microbiota and fecal metabolite profiles of chickens with immunity to Eimeria mitis. Animals, 14(23), 3515. https://doi.org/10.3390/ani14233515
White, Z., Cabrera, I., Mei, L., ... & Sano, T. (2025). Gut inflammation promotes microbiota-specific CD4 T cell-mediated neuroinflammation. Nature.
https://doi.org/10.1038/s41586-025-07722-z
Wu, S.-B., Rodgers, N. J., Cui, G., ... & Choct, M. (2016). Dynamics of intestinal metabolites and morphology in response to necrotic enteritis challenge in broiler chickens. Avian Pathology, 45(3), 346–356. https://doi.org/10.1080/03079457.2016.1151469
Xu, H., Yang, M., Fu, J., ... & Guo, Y. (2025). Usnic acid and tannic acid as inhibitors of coccidia and Clostridium perfringens: alleviating necrotic enteritis and improving intestinal health in broiler chickens. Journal of Animal Science and Biotechnology, 16, 69. https://doi.org/10.1186/s40104-025-01257-2
Yadav, S., Jha, R., Gupta, P. K., & Chopra, A. (2022). Influence of rapseed, canola meal and glucosinolates: effect on growth performance, and gut health in Salmonella Typhimurium challenged broiler chickens. Poultry Science, 101(2), 101566.
doi: 10.1016/j.psj.2021.101551
Yu, M., Li, Z., Chen, W., Wang, G., Cui, Y., & Ma, X. (2019). Dietary supplementation with citrus extract altered the intestinal microbiota and microbial metabolite profiles and enhanced the mucosal immune homeostasis in yellow-feathered broilers. Frontiers in Microbiology, 10, 2662. https://doi.org/10.3389/fmicb.2019.02662
Yu, M., Li, Z., Wang, G., Wang, F., Cui, Y., & Ma, X. (2020). Dietary supplementation with citrus extract alters the plasma parameters, circulating amino acid profiles and gene expression of small intestinal nutrient transporters in Chinese yellow-feathered broilers. Journal of the Science of Food and Agriculture, 100(15), 5611-5619. DOI: 10.1002/jsfa.10525
Zhang, Y., Chen, R., Zhang, D., Liu, Y. (2023). Metabolite interactions between host and microbiota during health and disease: Which feeds the other?. 160. Biomedicine and Pharmacotherapy. https://doi.org/10.1016/j.biopha.2023.114295
Zierer, J., Jackson, M. A., Kastenmüller, G., Menni, C. (2018). The fecal metabolome as a functional readout of the gut microbiome. Nature Genetics, 50(6): 790-795.
doi: 10.1038/s41588-018-0135-7
- Bai, H., Shi, L., Guo, Q., Zou, J., Jiao, H., Wang, Y., & Chang, G. (2023). Metagenomic insights into the relationship between gut microbiota and residual feed intake of small-sized meat ducks. Frontiers in Microbiology, 13, 1-11. https://doi.org/10.3389/fmicb.2022.1075610
- Bassols, A., Amigó, N., Pérez-Rodado, M., Tibau, J., & Martí, S. (2025). Metagenomic insights into the relationship between gut microbiota and residual feed intake of small-sized meat ducks. Frontiers in Microbiology, 13, 1-11. https://doi.org/10.3389/fmicb.2022.1075610
- Brugaletta, G., Zappaterra, M., Mattioli, S., Sirri, F., & Meluzzi, A. (2020). Effect of alternative administration programs of a synbiotic supplemenet, foot pad dermatitis, cecal microbiota, and blood metabolites. Animals, 10(3), 522. https://doi.org/10.3390/ani10030522
- Bucław, M. (2016). The use of inulin in poultry feeding: A review. Journal of Animal Physiology and Animal Nutrition, 100(6), 1015-1022. https://doi.org/10.1111/jpn.12484
- Chen, L., Ding, H., Zhu, Y., Hu, S., Wang, S., Wang, R., Liu, X., Jin, S., Chen, Q., & Zhang, T. (2023). Untargeted and targeted metabolomics identify metabolite biomarkers for Salmonella enteritidis in chicken meat. Food Chemistry, 429, Article 136834. https://doi.org/10.1016/j.foodchem.2022.135294
- Choi, S., & Kim, E. B. (2023). A comprehensive longitudinal study of gut microbiota dynamic changes in laying hens at four growth stages prior to egg production. Animal Bioscience, 36(4), 637–648. doi: 10.5713/ab.23.0271
- Cisse, S., Matuszewski, A., Bień, D., Konieczka, P., Kozłowski, K., Rawski, M., ... & Benarbia, M. E. A. (2025). A comprehensive longitudinal study of gut microbiota dynamic changes in laying hens at four growth stages prior to egg production. Animal Bioscience, 36(4), 637–648. https://doi.org/10.3390/ani15020127
- De Meyer, F., Eeckhaut, V., Ducatelle, R., Dhaenens, M., Daled, S., Dedeurwaerder, A., Van Denberghe, W., Deforce, D., & Van Immerseel, F. (2019). Host intestinal biomarker identification in a gut leakage model in broilers. Veterinary Research, 50, Article 46. https://doi.org/10.1186/s13567-019-0663-x
- de Souza, M., Cicero, C. E., Menck-Costa, M. F., Oliveira, M. L. A. G., Correia, R. T. P., & Bracarense, A. P. F. R. L. (2021). Histological evaluation of the intestine of broiler chickens: Comparison of three sampling methods. Semina: Ciências Agrárias, 42(3), 1391–1400. https://doi.org/10.5433/1679-0359.2021v42n6p3247
- Fathima, S., Al Hakeem, W. G., Shanmugasundaram, R., ... & Selvaraj, R. K. (2024). The effect of supplemental arginine on the gut microbial homeostasis of broilers during sub-clinical necrotic enteritis challenge. Frontiers in Physiology, 15, 1291836. https://doi.org/10.3389/fphys.2024.1291836
- Santanilla F., E. B., Betancourt López, L. L., Contreras Rodríguez, L. E., & Granados Falla, D. S. (2024). Resistant starch from a tuberous root from the Andes cordillera improves metabolic and immune parameters in broilers. Bioactive Carbohydrates and Dietary Fibre, 31, 100372. https://doi.org/10.1016/j.bcdf.2024.100420
- Gautam, H., Ahmad, S. N., Banaganapalli, B., Popowich, S., Chow-Lockerbie, B., Ayalew, L. E., Mandal, R., Wishart, D. S., Tikoo, S., & Gomis, S. (2025). Elevated butyric acid and histamine in feces and serum as an indicator of onset of necrotic enteritis in broiler chickens. Frontiers in Microbiology, 16, 1581309. https://doi.org/10.3389/fmicb.2025.1581309
- Hartinger, K., Fröschl, K., Ebbing, M. A., Bruschek-Pfleger, B., Schedle, K., Schwarz, C., & Gierus, M. (2022). Suitability of Hermetia illucens larvae meal and fat in broiler diets: Effects on animal performance, apparent ileal digestibility, gut histology, and microbial metabolites. Journal of Animal Science and Biotechnology, 13, 50. https://doi.org/10.1186/s40104-022-00701-7
- Karl, J. P., Armstrong, N. J., Player, R. A., McClung, H. L. (2022). The fecal metabolome links diet composition, food processing, and the gut microbiota to gastrointestinal health in a randomized trial of adults consuming a processed diet. Journal of Nutrition. https://doi.org/10.1093/jn/nxac161
- Kayal, A., Yu, S. J., Van, T. T. H., Moore, R. J., & Stanley, D. (2025). Effect of early gut microbiota intervention using pre-designed poultry microbiota substitute on broiler health and performance. Animal Production Science, 65(1), 11–22. https://doi.org/10.1071/an24354
- Khalili, L., & Amini, A. (2015). Resistant starch in food industry. In Polysaccharides: Bioactivity and Biotechnology, 2024-2056. Springer. DOI:10.1007/978-3-319-03751-6_42-1
- Kozłowska, I., Marć-Pieńkowska, J., & Bednarczyk, M. (2016). Beneficial aspects of inulin supplementation as a fructooligosaccharide prebiotic in monogastric animal nutrition - A review. Annals of Animal Science, 16(4), 935-962. DOI: 10.1515/aoas-2015-0090
- Liu, Y. S., Zhang, Y. Y., Li, J. L., Wang, T., & Gao, F. (2020). Growth performance, carcass traits and digestive function of broiler chickens fed diets with graded levels of corn resistant starch. British Poultry Science, 61(2), 146-155. https://doi.org/10.1080/00071668.2019.1694137
- Ma, N., Zhao, Y., Wang, J., Li, Z., Tian, X., Zhang, P., ... & Wang, J. (2023). Inulin supplementation restores intestinal microbiota and gut barrier in three breeds of laying hens. Poultry Science, 102(2). 102266
- Mon, K. K. Z., Zhu, Y., Chanthavixay, G., ... & Zhou, H. (2020). Integrative analysis of gut microbiome and metabolites revealed novel mechanisms of intestinal Salmonella carriage in chicken. Scientific Reports, 10, 10107. doi: 10.1038/s41598-020-60892-9
- Montes-Vergara, D. E., Cardona-Alvarez, J., & Pérez-Cordero, A. (2021). Prevalence of gastrointestinal parasites in three groups of domestic poultry managed under backyard system in the Savanna subregion, Department of Sucre, Colombia. Journal of Advanced Veterinary and Animal Research, 8(1), 32–38. http://doi.org/10.5455/javar.2021.h551
- Nam, S. L., Tarazona Carrillo, K., de la Mata, A. P., Harynuk, J. J. (2023). Untargeted metabolomic profiling of aqueous and lyophilized pooled human feces from two diet cohorts using two-dimensional gas chromatography coupled with time-of-flight mass spectrometry. Metabolites. https://doi.org/10.3390/metabo13070828
- Naumova, N. B., Alikina, T. Y., Zolotova, N. S., Konev, A. V., Pleshakova, V. I., Lescheva, N. A., & Kabilov, M. R. (2021). Bacillus-based probiotic treatment modified bacteriobiome diversity in duck feces. Agriculture, 11(5), 406. https://doi.org/10.3390/agriculture11050406
- Oluseyifunmi, A., Smith, O., Johnson, M., & Anderson, D. (2024). Role of resistant starch and dietary fiber in modulation of gut health biomarkers in broilers. Animal Nutrition, 10(1), 55–654.
- Philip, D., Hodgkiss, R., Radhakrishnan, S. K., Acharjee, A. (2025). Deciphering microbial and metabolic influences in gastrointestinal diseases-unveiling their roles in gastric cancer, colorectal cancer, and inflammatory bowel disease. Journal of Translational Medicine. https://doi.org/10.1186/s12967-025-06552-w
- Pires, P. G. D. S., Cardinal, K. M., Elnesr, S. S., Fraceto, L. F., de Castro, F. L. S., & Moraes, P. D. O. (2025). Non-invasive biomarkers for monitoring intestinal health in broilers – A systematic review. Research in Veterinary Science, 162, 209-223. https://doi.org/10.1016/j.rvsc.2025.105669
- Rath, N. C., Gupta, A., Liyanage, R., & Lay, J. O. (2019). Phorbol 12-Myristate 13-Acetate-Induced Changes in Chicken Enterocytes. Proteomics Insights, 10, 1178641819851392 https://doi.org/10.1177/1178641819851392
- Rysman, K., Eeckhaut, V., Ducatelle, R., & Van Immerseel, F. (2023). The fecal biomarker ovotransferrin associates with broiler performance under field conditions. Poultry Science, 102, Article 102585. DOI: 10.1016/j.psj.2023.103011
- Salahi, A., Abd El-Ghany, W. A., Attia, Y. A., ... & Tufarelli, V. (2025). Gut dysbiosis: Nutritional causes and risk prevention in poultry, with reference to other animals. South African Journal of Animal Science, 55(1), 8–20.
- Song, J., Li, Q., Everaert, N., Liu, R., Zheng, M., Zhao, G., ... & Wen, J. (2020). Dietary inulin supplementation modulates short-chain fatty acid levels and cecum microbiota composition and function in chickens infected with Salmonella. Frontiers in Microbiology, 11. https://doi.org/10.3389/fmicb.2020.584380
- Susanti, R., Yuniastuti, A., & Fibriana, F. (2020). Metagenome analysis of gut microbial in both the caged and non-caged ducks. Journal of Physics: Conference Series, 1467, 012024.
- Taleuzzaman, M., Anupam, Verma, M., Choudhary, R. (2025). Gut microbial metabolites as diagnostic biomarkers. Gut Microbiota and their Impact on Disease Pathways and Interventions. DOI: 10.2174/9789815324549125010012
- Ul Saqib, N., Islam, Z., Sultan, A., Ahmad, S., Raziq, F., & Jan, A. U. (2025). Effect of dried orange (Citrus sinensis) pulp on growth performance, serum biochemical parameters, and nutrient digestibility in broiler chickens. Pakistan Journal of Zoology, 57(1), 123-132. DOI:10.17582/journal.pjz/20230803122156
- Wang, S., Chen, L., He, M., Shen, J., Yin, J., Lu, L., & Wang, Y. (2018). Different rearing conditions alter gut microbiota composition and host physiology in Shaoxing ducks. Scientific Reports, 8, 7387. DOI: 10.1038/s41598-018-25760-7
- Wang, Z., Shang, P., Song, X., Wu, M., Zhang, T., Zhao, Q., Zhu, S., Qiao, Y., Zhao, F., Zhang, R., Jinwen Wang, Yu, Y., Han, H., & Dong, H. (2024). Alterations in ileal microbiota and fecal metabolite profiles of chickens with immunity to Eimeria mitis. Animals, 14(23), 3515. https://doi.org/10.3390/ani14233515
- White, Z., Cabrera, I., Mei, L., ... & Sano, T. (2025). Gut inflammation promotes microbiota-specific CD4 T cell-mediated neuroinflammation. Nature.
- https://doi.org/10.1038/s41586-025-07722-z
- Wu, S.-B., Rodgers, N. J., Cui, G., ... & Choct, M. (2016). Dynamics of intestinal metabolites and morphology in response to necrotic enteritis challenge in broiler chickens. Avian Pathology, 45(3), 346–356. https://doi.org/10.1080/03079457.2016.1151469
- Xu, H., Yang, M., Fu, J., ... & Guo, Y. (2025). Usnic acid and tannic acid as inhibitors of coccidia and Clostridium perfringens: alleviating necrotic enteritis and improving intestinal health in broiler chickens. Journal of Animal Science and Biotechnology, 16, 69. https://doi.org/10.1186/s40104-025-01257-2
- Yadav, S., Jha, R., Gupta, P. K., & Chopra, A. (2022). Influence of rapseed, canola meal and glucosinolates: effect on growth performance, and gut health in Salmonella Typhimurium challenged broiler chickens. Poultry Science, 101(2), 101566.
- doi: 10.1016/j.psj.2021.101551
- Yu, M., Li, Z., Chen, W., Wang, G., Cui, Y., & Ma, X. (2019). Dietary supplementation with citrus extract altered the intestinal microbiota and microbial metabolite profiles and enhanced the mucosal immune homeostasis in yellow-feathered broilers. Frontiers in Microbiology, 10, 2662. https://doi.org/10.3389/fmicb.2019.02662
- Yu, M., Li, Z., Wang, G., Wang, F., Cui, Y., & Ma, X. (2020). Dietary supplementation with citrus extract alters the plasma parameters, circulating amino acid profiles and gene expression of small intestinal nutrient transporters in Chinese yellow-feathered broilers. Journal of the Science of Food and Agriculture, 100(15), 5611-5619. DOI: 10.1002/jsfa.10525
- Zhang, Y., Chen, R., Zhang, D., Liu, Y. (2023). Metabolite interactions between host and microbiota during health and disease: Which feeds the other?. 160. Biomedicine and Pharmacotherapy. https://doi.org/10.1016/j.biopha.2023.114295
- Zierer, J., Jackson, M. A., Kastenmüller, G., Menni, C. (2018). The fecal metabolome as a functional readout of the gut microbiome. Nature Genetics, 50(6): 790-795.
- doi: 10.1038/s41588-018-0135-7