{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T15:49:01Z","timestamp":1780415341549,"version":"3.54.1"},"reference-count":56,"publisher":"MDPI AG","issue":"20","license":[{"start":{"date-parts":[[2025,10,13]],"date-time":"2025-10-13T00:00:00Z","timestamp":1760313600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100014579","name":"National Institute of Animal Science, Rural Development Administration, Republic of Korea","doi-asserted-by":"publisher","award":["PJ01569902"],"award-info":[{"award-number":["PJ01569902"]}],"id":[{"id":"10.13039\/501100014579","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Animals"],"abstract":"<jats:p>This study evaluated age-related changes in nutrient digestibility in dogs and examined the effects of physiological development and dietary composition on digestive efficiency. Twenty Beagle dogs were assigned to three groups: puppies (&lt;1 year; n = 8), adults (3\u20134 years; n = 8), and seniors (10\u201311 years; n = 4). All animals were fed diets formulated to contain identical nutrient levels that met or exceeded the minimum recommended nutrient requirements established by the Association of American Feed Control Officials. The digestibility of dry matter (DM), crude protein (CP), ether extract (EE), nitrogen-free extract (NFE), calcium (Ca), phosphorus (P), and amino acids were compared among the groups. The results showed that NFE digestibility was significantly higher in puppies, whereas CP digestibility was lower than that in adults and seniors, likely due to immature digestive function. In addition, EE digestibility was significantly lower in puppies, whereas P digestibility decreased with age. No significant difference was observed in Ca digestibility. Amino acid digestibility is lower in puppies, particularly for essential amino acids such as lysine, isoleucine, histidine, and arginine. These results indicate that age-related differences in digestive physiology and protein source affect nutrient utilization, providing a basis for developing life stage-specific nutritional strategies for companion animals.<\/jats:p>","DOI":"10.3390\/ani15202963","type":"journal-article","created":{"date-parts":[[2025,10,14]],"date-time":"2025-10-14T07:51:28Z","timestamp":1760428288000},"page":"2963","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Comparative Evaluation of Nutrient Digestibility in Beagle Dogs of Different Life Stages"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4860-6290","authenticated-orcid":false,"given":"Min Young","family":"Lee","sequence":"first","affiliation":[{"name":"Animal Welfare Division, National Institute of Animal Science, Rural Development Administration, Wanju 55365, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9497-3345","authenticated-orcid":false,"given":"Kyoung-Min","family":"So","sequence":"additional","affiliation":[{"name":"Animal Welfare Division, National Institute of Animal Science, Rural Development Administration, Wanju 55365, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8024-1135","authenticated-orcid":false,"given":"Sang-Yeob","family":"Lee","sequence":"additional","affiliation":[{"name":"Animal Welfare Division, National Institute of Animal Science, Rural Development Administration, Wanju 55365, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4861-4637","authenticated-orcid":false,"given":"Woo-Do","family":"Lee","sequence":"additional","affiliation":[{"name":"Animal Welfare Division, National Institute of Animal Science, Rural Development Administration, Wanju 55365, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3620-9952","authenticated-orcid":false,"given":"Hyun-Woo","family":"Cho","sequence":"additional","affiliation":[{"name":"Animal Welfare Division, National Institute of Animal Science, Rural Development Administration, Wanju 55365, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0441-3542","authenticated-orcid":false,"given":"Han Tae","family":"Bang","sequence":"additional","affiliation":[{"name":"Animal Welfare Division, National Institute of Animal Science, Rural Development Administration, Wanju 55365, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5238-2982","authenticated-orcid":false,"given":"Seyeon","family":"Chang","sequence":"additional","affiliation":[{"name":"Animal Welfare Division, National Institute of Animal Science, Rural Development Administration, Wanju 55365, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1751-8418","authenticated-orcid":false,"given":"Won Yong","family":"Jung","sequence":"additional","affiliation":[{"name":"Animal Welfare Division, National Institute of Animal Science, Rural Development Administration, Wanju 55365, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6152-8536","authenticated-orcid":false,"given":"Kangmin","family":"Seo","sequence":"additional","affiliation":[{"name":"Ingredient Examination Division, Experiment Research Institute, National Agricultural Products Quality Management Service, Gimcheon 39660, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4618-586X","authenticated-orcid":false,"given":"Ju Lan","family":"Chun","sequence":"additional","affiliation":[{"name":"Animal Welfare Division, National Institute of Animal Science, Rural Development Administration, Wanju 55365, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9834-2126","authenticated-orcid":false,"given":"Ki Hyun","family":"Kim","sequence":"additional","affiliation":[{"name":"Academic-Industrial Cooperation Organization, Sunchon National University, Suncheon 57922, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,10,13]]},"reference":[{"key":"ref_1","first-page":"1","article-title":"Pet humanisation: What is it and does it influence purchasing behaviour?","volume":"5","author":"Forbes","year":"2018","journal-title":"J. Dairy Vet. Sci."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1016\/j.rvsc.2020.02.008","article-title":"Natural food for domestic animals: A national and international technological review","volume":"130","author":"Viana","year":"2020","journal-title":"Res. Vet. Sci."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"42","DOI":"10.1590\/S1516-35982010001300006","article-title":"Nutritional management and disease prevention in healthy dogs and cats","volume":"39","author":"Fascetti","year":"2010","journal-title":"Rev. Bras. Zootec."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"578","DOI":"10.12968\/coan.2014.19.11.578","article-title":"Nutrition (part 1): Life stage diets","volume":"19","author":"Bowland","year":"2014","journal-title":"Comp. Anim."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"153","DOI":"10.5326\/JAAHA-MS-7232","article-title":"2021 AAHA nutrition and weight management guidelines for dogs and cats","volume":"57","author":"Cline","year":"2021","journal-title":"J. Am. Anim. Hosp. Assoc."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"62","DOI":"10.51585\/gjvr.2024.1.0076","article-title":"Nutritional risks and consequences of meat-only diets for dogs and cats","volume":"4","author":"Tazerji","year":"2024","journal-title":"Ger. J. Vet. Res."},{"key":"ref_7","first-page":"32","article-title":"Role of dietary protein in weight management","volume":"21","author":"Hannah","year":"1999","journal-title":"Compend. Contin. Educ. Pract. Vet."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Hou, Y., Wu, Z., Dai, Z., Wang, G., and Wu, G. (2017). Protein hydrolysates in animal nutrition: Industrial production, bioactive peptides, and functional significance. J. Anim. Sci. Biotechnol., 8.","DOI":"10.1186\/s40104-017-0153-9"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"2145S","DOI":"10.1093\/jn\/134.8.2145S","article-title":"Fatty acid composition in commercial dog foods","volume":"134","author":"Krogdahl","year":"2004","journal-title":"J. Nutr."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Jackson, M.I. (2024). Replacement of dietary carbohydrate with protein versus fat differentially alters postprandial circulating hormones and macronutrient metabolism in dogs. Metabolites, 14.","DOI":"10.3390\/metabo14070373"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"e4","DOI":"10.4081\/ijas.2013.e4","article-title":"Fermentation characteristics of several carbohydrate sources for dog diets using the in vitro gas production technique","volume":"12","author":"Carciofi","year":"2013","journal-title":"Ital. J. Anim. Sci."},{"key":"ref_12","first-page":"1","article-title":"Genetic disorders of calcium, phosphorus, and bone homeostasis","volume":"3","author":"Root","year":"2018","journal-title":"Transl. Sci. Rare Dis."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Hariprasanna, K., Chetankumar, B., Venkateswarlu, R., and Niharika, G. (2021). Approaches for enhancing the nutrients bioavailability. Sorghum in the 21st Century: Food\u2013Fodder\u2013Feed\u2013Fuel for a Rapidly Changing World, Springer.","DOI":"10.1007\/978-981-15-8249-3_32"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"4788","DOI":"10.2527\/jas.2015-9231","article-title":"Protein and amino acid bioavailability estimates for canine foods","volume":"93","author":"Hendriks","year":"2015","journal-title":"J. Anim. Sci."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"677","DOI":"10.2460\/ajvr.2002.63.677","article-title":"Influence of age and body size on gastrointestinal transit time of radiopaque markers in healthy dogs","volume":"63","author":"Weber","year":"2002","journal-title":"Am. J. Vet. Res."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"425","DOI":"10.1146\/annurev.nutr.28.061807.155325","article-title":"Age-related changes in nutrient utilization by companion animals","volume":"28","author":"Fahey","year":"2008","journal-title":"Annu. Rev. Nutr."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1927","DOI":"10.1111\/jpn.13258","article-title":"Endogenous fat losses and true and apparent fat di-gestibility in adult and growing dogs fed diets containing poultry offal fat","volume":"104","author":"Sabchuk","year":"2020","journal-title":"J. Anim. Physiol. Anim. Nutr."},{"key":"ref_18","unstructured":"National Research Council (NRC) (2006). Nutrient Requirements of Dogs and Cats, National Academies Press."},{"key":"ref_19","unstructured":"Association of American Feed Control Officials (AAFCO) (2021). Dog and Cat Food Nutrient Profiles. Official Publication, AAFCO."},{"key":"ref_20","unstructured":"National Research Council (NRC) (1985). Nutrient Requirements of Dogs, National Academies Press."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Carapeto, S., Cunha, E., Serrano, I., Pascoal, P., Pereira, M., Abreu, R., Neto, S., Antunes, B., Dias, R., and Tavares, L. (2023). Effect of the administration of a lyophilised faecal capsules on the intestinal microbiome of dogs: A pilot study. Genes, 14.","DOI":"10.3390\/genes14091676"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"920","DOI":"10.3109\/00365529709011203","article-title":"Stool form scale as a useful guide to intestinal transit time","volume":"32","author":"Lewis","year":"1997","journal-title":"Scand. J. Gastroenterol."},{"key":"ref_23","unstructured":"Patil, A.R., and Bisby, T.M. (2001). Comparison of Maintenance Energy Requirement of Client-Owned Dogs and Kennel Dogs, Purina Nutrition Forum."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"S22","DOI":"10.1093\/jn\/121.suppl_11.S22","article-title":"Evaluation of the energy requirements of adult kennel dogs","volume":"121","author":"Finke","year":"1991","journal-title":"J. Nutr."},{"key":"ref_25","first-page":"149","article-title":"Untersuchungen zum Energiebedarf des Hundes in Abh\u00e4ngigkeit von Rassezugeh\u00f6rigkeit und Alter","volume":"35","author":"Rainbird","year":"1990","journal-title":"Kleintierpraxis"},{"key":"ref_26","first-page":"294","article-title":"Digestibility in labrador retrievers during growth","volume":"52","author":"Gilham","year":"1993","journal-title":"Proc. Nutr. Soc."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1713","DOI":"10.2527\/2004.8261713x","article-title":"Diet affects nutrient digestibility, hematology, and serum chemistry of senior and weanling dogs","volume":"82","author":"Swanson","year":"2004","journal-title":"J. Anim. Sci."},{"key":"ref_28","unstructured":"Reinhart, G.A., and Carey, D.P. (2000). Development and adaptation of hydrolytic and absorptive functions of the canine small intestine. Recent Advances in Canine and Feline Nutrition, Vol. II: 1998 Iams Nutrition Symposium Proceedings, Orange Frazer Press."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"347","DOI":"10.1079\/BJN19810110","article-title":"Digestion in the pigs between 7 and 35 d of age. 4. The digestion of amino acids in pigs given milk and soya-bean proteins","volume":"45","author":"Wilson","year":"1981","journal-title":"Br. J. Nutr."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"100439","DOI":"10.1016\/j.animal.2021.100439","article-title":"Age-dependent development in protein digestibility and intestinal morphology in weaned pigs fed different protein sources","volume":"16","author":"Hedemann","year":"2022","journal-title":"Animal"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1512385","DOI":"10.1080\/1828051X.2018.1512385","article-title":"Effect of potato on kibble characteristics and diet digestibility and palatability to adult dogs and puppies","volume":"18","author":"Domingues","year":"2019","journal-title":"Ital. J. Anim. Sci."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"2794","DOI":"10.2527\/jas.2011-4662","article-title":"Digestibility and metabolizable energy of raw soybeans manufactured with different processing treatments and fed to adult dogs and puppies","volume":"91","author":"Zanatta","year":"2013","journal-title":"J. Anim. Sci."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"784","DOI":"10.1590\/S0102-09352011000300038","article-title":"Digestibility of dry extruded food in adult dogs and puppies","volume":"63","author":"Zanatta","year":"2011","journal-title":"Arq. Bras. Med. Vet. Zootec."},{"key":"ref_34","first-page":"771","article-title":"Clinical aspect of recent progress in phosphate metabolism. Distribution of phosphorus and its physiological roles in the body: The form, distribution, and physiological function","volume":"19","author":"Yano","year":"2009","journal-title":"Clin. Calcium."},{"key":"ref_35","unstructured":"Watson, R.R. (2017). Phosphorus: Basic nutritional aspects. Molecular, Genetic, and Nutritional Aspects of Major and Trace Minerals, Academic Press. [1st ed.]."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"497","DOI":"10.1093\/jn\/57.4.497","article-title":"Transfer of phosphate in the digestive tract I","volume":"57","author":"Smith","year":"1955","journal-title":"Swine. J. Nutr."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Vorland, C.J., Lachcik, P.J., Aromeh, L.O., Moe, S.M., Chen, N.X., and Hill Gallant, K.M. (2018). Effect of dietary phosphorus intake and age on intestinal phosphorus absorption efficiency and phosphorus balance in male rats. PLoS ONE, 13.","DOI":"10.1371\/journal.pone.0207601"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"100","DOI":"10.1016\/j.livsci.2010.06.110","article-title":"Phosphorus digestibility is highly influenced by phytase but slightly by calcium in growing pigs","volume":"134","author":"Poulsen","year":"2010","journal-title":"Livest. Sci."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"1","DOI":"10.5713\/ajas.2014.r.01","article-title":"Calcium digestibility and metabolism in pigs","volume":"27","author":"Stein","year":"2014","journal-title":"Asian-Australas. J. Anim. Sci."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"605","DOI":"10.1111\/jpn.12258","article-title":"Phytate in pig and poultry nutrition","volume":"99","author":"Humer","year":"2015","journal-title":"J. Anim. Physiol. Anim. Nutr."},{"key":"ref_41","first-page":"929","article-title":"Long story from past to present: Calcium, phosphorus, and phytase","volume":"25","author":"Raei","year":"2024","journal-title":"Ann. Anim. Sci."},{"key":"ref_42","first-page":"2792","article-title":"Relationship between gut microbiota and phosphorus metabolism in hemodialysis patients: A preliminary exploration","volume":"131","author":"Miao","year":"2018","journal-title":"Chin. Med. J."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s00726-009-0269-0","article-title":"Amino acids: Metabolism, functions, and nutrition","volume":"37","author":"Wu","year":"2009","journal-title":"Amino Acids"},{"key":"ref_44","unstructured":"Lopez, M.J., and Mohiuddin, S.S. (2024, April 30). Biochemistry, essential amino acids, StatPearls [Internet], Available online: https:\/\/www.ncbi.nlm.nih.gov\/books\/NBK557845\/."},{"key":"ref_45","unstructured":"Bagchi, D., Nair, S., and Sen, C.K. (2019). An overview on essential amino acids and branched chain amino acids. Nutrition and Enhanced Sports Performance, Academic Press. [2nd ed.]."},{"key":"ref_46","doi-asserted-by":"crossref","unstructured":"Moro, J., Tom\u00e9, D., Schmidely, P., Demersay, T.-C., and Azzout-Marniche, D. (2020). Histidine: A systematic review on metabolism and physiological effects in human and different animal species. Nutrients, 12.","DOI":"10.3390\/nu12051414"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"1626S","DOI":"10.1093\/jn\/137.6.1626S","article-title":"Nutritional consequences of interspecies differences in arginine and lysine metabolism","volume":"137","author":"Ball","year":"2007","journal-title":"J. Nutr."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"40","DOI":"10.1093\/jn\/111.1.40","article-title":"Lysine requirements of the immature dog","volume":"111","author":"Milner","year":"1981","journal-title":"J. Nutr."},{"key":"ref_49","doi-asserted-by":"crossref","unstructured":"Lippi, I., Perondi, F., Pierini, A., Bartoli, F., Gori, E., Mariti, C., and Marchetti, V. (2022). Essential and non-essential amino acids in dogs at different stages of chronic kidney disease. Vet. Sci., 9.","DOI":"10.3390\/vetsci9070331"},{"key":"ref_50","first-page":"83","article-title":"Changes in body composition and energy balance with aging","volume":"3","author":"Armstrong","year":"1996","journal-title":"Vet. Clin. Nutr."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"2632S","DOI":"10.1093\/jn\/128.12.2632S","article-title":"Changing perspectives on aging and energy requirements: Aging and digestive function in humans, dogs and cats","volume":"128","author":"Harper","year":"1998","journal-title":"J. Nutr."},{"key":"ref_52","doi-asserted-by":"crossref","unstructured":"Schauf, S., Stockman, J., Haydock, R., Eyre, R., Fortener, L., Park, J.S., Bakke, A.M., and Watson, P. (2021). Healthy ageing is associated with preserved or enhanced nutrient and mineral apparent digestibility in dogs and cats fed commercially relevant extruded diets. Animals, 11.","DOI":"10.3390\/ani11072127"},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"1496","DOI":"10.1002\/hep.1840190627","article-title":"Hepatobiliary function in senescent male Prague-Dawley rats","volume":"19","author":"Handler","year":"1994","journal-title":"Hepatology"},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"625","DOI":"10.2460\/javma.1999.215.05.625","article-title":"Age-related changes to nutritional requirements and digestive function in adult dogs and cats","volume":"215","author":"Burkholder","year":"1999","journal-title":"J. Am. Vet. Med. Assoc."},{"key":"ref_55","first-page":"324","article-title":"Nutrition and metabolism of the geriatric dog","volume":"75","author":"Sheffy","year":"1985","journal-title":"Cornell Vet."},{"key":"ref_56","unstructured":"F\u00e9d\u00e9ration Europ\u00e9enne de l\u2019Industrie des Aliments pour Animaux Familiers (FEDIAF) (2024). Nutritional Guidelines for Complete and Complementary Pet Food for Cats and Dogs, European Pet Food Industry Federation."}],"container-title":["Animals"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-2615\/15\/20\/2963\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,15]],"date-time":"2025-10-15T06:50:45Z","timestamp":1760511045000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-2615\/15\/20\/2963"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,10,13]]},"references-count":56,"journal-issue":{"issue":"20","published-online":{"date-parts":[[2025,10]]}},"alternative-id":["ani15202963"],"URL":"https:\/\/doi.org\/10.3390\/ani15202963","relation":{},"ISSN":["2076-2615"],"issn-type":[{"value":"2076-2615","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,10,13]]}}}