{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T04:30:40Z","timestamp":1787027440289,"version":"build-2736575974"},"reference-count":93,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2020,12,17]],"date-time":"2020-12-17T00:00:00Z","timestamp":1608163200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Animals"],"abstract":"<jats:p>The aim of the experiment was to assess the effect of dietary alpha-ketoglutarate (AKG) supplementation on performance, serum hormonal indices, duodenum and jejunum histomorphometry, meat quality characteristics, bone quality traits and cartilage degradation in laying hens with a mature skeletal system. Forty-eight 30 week-old Bovans Brown laying hens were randomly assigned to a control group or the group fed the basal diet plus 1.0% AKG. The experimental trial lasted 30 weeks. The supplementation of AKG increases blood serum content of leptin, ghrelin, bone alkaline phosphatate and receptor activator of nuclear factor kappa-\u0392 ligand, while osteoprotegerin and osteocalcin decrease. While dietary AKG was given to laying hens negatively influenced villus length, crypt depth, villus\/crypt ratio and absorptive surface area in duodenum and jejunum, these changes have no effect on feed intake, weight gain, nor laying performance. In breast muscles, no significant changes in skeletal muscle fatty acid composition were observed, however, a higher shear force and decreased cholesterol content following AKG supplementation were noted, showing the improvement of muscle quality. While dietary AKG supplementation did not affect the general geometric and mechanical properties of the tibia, it increased collagen synthesis and enhanced immature collagen content. In medullary bone, an increase of bone volume fraction, trabecular thickness, fractal dimension and decrease of trabecular space were observed in AKG supplemented group. The trabeculae in bone metaphysis were also significantly thicker after AKG supplementation. AKG promoted fibrillogenesis in articular cartilage, as indicated by increased cartilage oligomeric matrix protein immunoexpression. By improving the structure and maintaining the proper bone turnover rate of highly reactive and metabolically active medullar and trabecular bones AKG showed its anti-osteoporotic action in laying hens.<\/jats:p>","DOI":"10.3390\/ani10122420","type":"journal-article","created":{"date-parts":[[2020,12,17]],"date-time":"2020-12-17T21:21:49Z","timestamp":1608240109000},"page":"2420","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":23,"title":["Alpha-Ketoglutarate: An Effective Feed Supplement in Improving Bone Metabolism and Muscle Quality of Laying Hens: A Preliminary Study"],"prefix":"10.3390","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7574-2653","authenticated-orcid":false,"given":"Ewa","family":"Tomaszewska","sequence":"first","affiliation":[{"name":"Department of Animal Physiology, Faculty of Veterinary Medicine, University of Life Sciences in Lublin, Akademicka St. 12, 20-950 Lublin, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sylwester","family":"\u015awi\u0105tkiewicz","sequence":"additional","affiliation":[{"name":"Department of Animal Nutrition and Feed Science, National Research Institute of Animal Production, Krakowska St. 1, 32-083 Balice, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7037-7338","authenticated-orcid":false,"given":"Anna","family":"Arczewska-W\u0142osek","sequence":"additional","affiliation":[{"name":"Department of Animal Nutrition and Feed Science, National Research Institute of Animal Production, Krakowska St. 1, 32-083 Balice, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4713-9902","authenticated-orcid":false,"given":"Dorota","family":"Wojtysiak","sequence":"additional","affiliation":[{"name":"Department of Animal Genetics, Breeding and Ethology, Faculty of Animal Sciences, University of Agriculture in Krak\u00f3w, 24\/28 Mickiewicza Ave., 30-059 Cracow, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5873-9666","authenticated-orcid":false,"given":"Piotr","family":"Dobrowolski","sequence":"additional","affiliation":[{"name":"Department of Functional Anatomy and Cytobiology, Faculty of Biology and Biotechnology, Maria Curie-Sklodowska University, Akademicka St. 19, 20-033 Lublin, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6917-571X","authenticated-orcid":false,"given":"Piotr","family":"Domaradzki","sequence":"additional","affiliation":[{"name":"Department of Commodity Science and Processing of Raw Animal Materials, Faculty of Animal Sciences and Bioeconomy, University of Life Sciences in Lublin, Akademicka St. 13, 20-950 Lublin, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1053-0948","authenticated-orcid":false,"given":"Izabela","family":"\u015awietlicka","sequence":"additional","affiliation":[{"name":"Department of Biophysics, Faculty of Environmental Biology, University of Life Sciences in Lublin, Akademicka St. 13, 20-950 Lublin, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Janine","family":"Donaldson","sequence":"additional","affiliation":[{"name":"School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, South Africa"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5039-009X","authenticated-orcid":false,"given":"Monika","family":"Hu\u0142as-Stasiak","sequence":"additional","affiliation":[{"name":"Department of Functional Anatomy and Cytobiology, Faculty of Biology and Biotechnology, Maria Curie-Sklodowska University, Akademicka St. 19, 20-033 Lublin, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4118-6302","authenticated-orcid":false,"given":"Siemowit","family":"Muszy\u0144ski","sequence":"additional","affiliation":[{"name":"Department of Biophysics, Faculty of Environmental Biology, University of Life Sciences in Lublin, Akademicka St. 13, 20-950 Lublin, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,12,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"555","DOI":"10.1080\/00071668908417179","article-title":"Broken bones in domestic fowl: Handling and processing damage in end-of-lay battery hens","volume":"30","author":"Gregory","year":"1989","journal-title":"Br. Poult. Sci."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"411","DOI":"10.1136\/vr.d6564","article-title":"The laying hen and bone fractures","volume":"169","author":"Sandilands","year":"2011","journal-title":"Vet. Rec."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1443","DOI":"10.3382\/ps.2012-02800","article-title":"Changes of blood parameters associated with bone remodeling following experimentally induced fatty liver disorder in laying hens","volume":"92","author":"Jiang","year":"2013","journal-title":"Poult. Sci."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"645","DOI":"10.1515\/aoas-2016-0098","article-title":"Infectious and non-infectious factors associated with leg disorders in poultry\u2014A review","volume":"17","author":"Rawski","year":"2017","journal-title":"Ann. Anim. Sci."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1115","DOI":"10.1515\/aoas-2016-0038","article-title":"The effect of dietary essential oil mixture supplementation on performance, egg quality and bone characteristics in laying hens","volume":"16","author":"Olgun","year":"2016","journal-title":"Ann. Anim. Sci."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"463","DOI":"10.1515\/aoas-2016-0055","article-title":"Effects of dietary supplementation of inorganic, organic or nano zinc forms on performance, eggshell quality, and bone characteristics in laying hens","volume":"17","author":"Olgun","year":"2017","journal-title":"Ann. Anim. Sci."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"167","DOI":"10.1515\/aoas-2017-0038","article-title":"Effect of selected feed additives on egg performance and eggshell quality in laying hens fed a diet with standard or decreased calcium content","volume":"18","author":"Krawczyk","year":"2018","journal-title":"Ann. Anim. Sci."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"184","DOI":"10.1093\/ps\/83.2.184","article-title":"Welfare implications of avian osteoporosis","volume":"83","author":"Webster","year":"2004","journal-title":"Poult. Sci."},{"key":"ref_9","unstructured":"FAWC (2010). Opinion on Osteoporosis and Bone Fractures in Laying Hens, Farm Animal Welfare Council."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"6","DOI":"10.3389\/fvets.2018.00006","article-title":"The influence of keel bone damage on welfare of laying hens","volume":"5","author":"Riber","year":"2018","journal-title":"Front. Vet. Sci."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Tomaszewska, E., Dobrowolski, P., \u015awi\u0105tkiewicz, M., Donaldson, J., Puzio, I., and Muszy\u0144ski, S. (2020). Is dietary 2-oxoglutaric acid effective in accelerating bone growth and development in experimentally induced intrauterine growth retarded gilts?. Animals, 10.","DOI":"10.3390\/ani10040728"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"563","DOI":"10.1515\/bvip-2015-0084","article-title":"The effect of HMB and 2-Ox administered during pregnancy on bone properties in primiparous and multiparous minks (Neivison vison)","volume":"59","author":"Tomaszewska","year":"2015","journal-title":"Bull. Vet. Inst. Pulawy"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"192","DOI":"10.1111\/j.1439-0396.2007.00805.x","article-title":"Alpha-ketoglutarate protects the liver of piglets exposed during prenatal life to chronic excess of dexamethasone from metabolic and structural changes","volume":"93","author":"Dobrowolski","year":"2009","journal-title":"J. Anim. Physiol. Anim. Nutr."},{"key":"ref_14","first-page":"117","article-title":"Effect of alpha-ketoglutarate (AKG) given to pregnant sows on development of humerus and femur in newborns","volume":"49","author":"Kowalik","year":"2005","journal-title":"Bull. Vet. Inst. Pulawy"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"EFSA (2020). Safety and efficacy of l-glutamine produced using Corynebacterium glutamicum NITE BP-02524 for all animal species. EFSA J., 18, 6075.","DOI":"10.2903\/j.efsa.2020.6075"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2700","DOI":"10.3382\/ps.2014-03910","article-title":"Response to dietary supplementation of L-glutamine and L-glutamate in broiler chickens reared at different stocking densities under the hot, humid tropical conditions","volume":"93","author":"Shakeri","year":"2014","journal-title":"Poult. Sci."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"79","DOI":"10.22358\/jafs\/69957\/1998","article-title":"Perspectives of glutamine and its derivatives as feed additives for farm animals","volume":"7","author":"Pierzynowski","year":"1998","journal-title":"J. Anim. Feed Sci."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"850S","DOI":"10.3945\/ajcn.2009.27462Y","article-title":"Metabolic fate and function of dietary glutamate in the gut","volume":"90","author":"Burrin","year":"2009","journal-title":"Am. J. Clin. Nutr."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1","DOI":"10.4062\/biomolther.2015.078","article-title":"Alpha-Ketoglutarate: Physiological functions and applications","volume":"24","author":"Wu","year":"2016","journal-title":"Biomol. Ther."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"100","DOI":"10.1016\/j.bone.2005.12.016","article-title":"Ornithine alpha-ketoglutarate increases mineralization and mechanical properties of tibia in turkeys","volume":"39","author":"Tatara","year":"2006","journal-title":"Bone"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1604","DOI":"10.1093\/ps\/84.10.1604","article-title":"Effect of alpha-ketoglutarate (AKG) on bone homeostasis and plasma amino acids in turkeys","volume":"84","author":"Tatara","year":"2005","journal-title":"Poult. Sci."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1186","DOI":"10.2741\/3783","article-title":"Alpha-ketoglutarate and intestinal function","volume":"16","author":"Hou","year":"2011","journal-title":"Front. Biosci."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1046\/j.1439-0396.2002.00380.x","article-title":"Absorption and metabolism of alpha-ketoglutarate in growing pigs","volume":"86","author":"Kristensen","year":"2002","journal-title":"J. Anim. Physiol. Anim. Nutr."},{"key":"ref_24","unstructured":"(2020, December 15). Commission Implementing Regulation (EU) 2018\/249 of 15 February 2018 Concerning the Authorisation of Taurine, Beta-Alanine, L-alanine, L-arginine, L-aspartic acid, L-histidine, D,L-isoleucine, L-leucine, L-phenylalanine, L-proline, D,L-serine, L-tyrosine, L-methionine, L-valine, L-cysteine, Glycine, Monosodium Glutamate and L-glutamic Acid as Feed Additives for all Animal Species and L-cysteine Hydrochloride Monohydrate for all Species Except Cats and Dogs. OJ L 53, 23 February 2018. Available online: https:\/\/eur-lex.europa.eu\/eli\/reg_impl\/2018\/249\/oj."},{"key":"ref_25","unstructured":"(2020, December 15). Commission Regulation (EC) 37\/2010 of 22 December 2009 on Pharmacologically Active Substances and their Classification Regarding Maximum Residue Limits of Veterinary Medicinal Products in Foodstuffs of Animal Origin. OJ L 15, 20 January 2010. Available online: http:\/\/data.europa.eu\/eli\/reg\/2010\/37(1)\/oj."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"563","DOI":"10.1292\/jvms.15-0385","article-title":"The effect of supplementation of glutamine precursor on the growth plate, articular cartilage and cancellous bone in fundectomy-induces osteopenic bone","volume":"78","author":"Tomaszewska","year":"2016","journal-title":"J. Vet. Med. Sci."},{"key":"ref_27","first-page":"107","article-title":"Influence of alpha-ketoglutarate (AKG) on mineral density and geometrical and mechanical parameters of femora during postnatal life in piglets","volume":"49","author":"Kowalik","year":"2005","journal-title":"Bull. Vet. Inst. Pulawy"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"2067","DOI":"10.1007\/s00726-016-2254-8","article-title":"The glutamine-alpha-ketoglutarate (AKG) metabolism and its nutritional implications","volume":"48","author":"Xiao","year":"2016","journal-title":"Amino Acids"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"60","DOI":"10.3923\/ijps.2009.60.68","article-title":"Influence of dietary glutamine supplementation on growth performance, small intestine morphology, immune response and some blood parameters of broiler chickens","volume":"8","author":"Soltan","year":"2009","journal-title":"Int. J. Poult. Sci."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1940","DOI":"10.1093\/ps\/86.9.1940","article-title":"The effect of supplemental glutamine on growth performance, development of the gastrointestinal tract, and humoral immune response of broilers","volume":"86","author":"Bartell","year":"2007","journal-title":"Poult. Sci."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"264","DOI":"10.3906\/vet-1210-32","article-title":"The effects of dietary glutamine supplementation on growth performance and intestinal morphology of broiler chickens reared under hot conditions","volume":"38","author":"Jazideh","year":"2014","journal-title":"Turk. J. Vet. Anim. Sci."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"555","DOI":"10.1007\/s00726-010-0473-y","article-title":"Dietary alpha-ketoglutarate supplementation ameliorates intestinal injury in lipopolysaccharide-challenged piglets","volume":"39","author":"Hou","year":"2010","journal-title":"Amino Acids"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"685","DOI":"10.2478\/aoas-2014-0028","article-title":"Influence of origin of laying hens on the quality of their carcasses and meat after the first laying period","volume":"14","author":"Krawczyk","year":"2014","journal-title":"Ann. Anim. Sci."},{"key":"ref_34","unstructured":"Smulikowska, S., and Rutkowski, A. (2018). Poultry Feeding Standards, The Kielanowski Institute of Animal Physiology and Nutrition PAS. [5th ed.]. (In Polish)."},{"key":"ref_35","first-page":"400","article-title":"Glutamine in diet of laying hens submitted to heat stress and thermoneutrality","volume":"12","year":"2011","journal-title":"Ci. Anim. Bras."},{"key":"ref_36","unstructured":"Janssen, W.M.M.A. (1989). European Table of Energy Values for Poultry Feedstuffs, Beekbergen. [3rd ed.]."},{"key":"ref_37","unstructured":"Suvarna, S.K., Layton, C.D., and Bancroft, J.D. (2008). Bancroft\u2019s Theory and Practice of Histological Techniques, Elsevier Health Sciences. [8th ed.]."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"671","DOI":"10.1038\/nmeth.2089","article-title":"NIH Image to ImageJ: 25 years of image analysis","volume":"9","author":"Schneider","year":"2012","journal-title":"Nat. Methods"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"131","DOI":"10.1007\/s102380200018","article-title":"A simple new method to calculate small intestine absorptive surface in the rat","volume":"2","author":"Kisielinski","year":"2002","journal-title":"Clin. Exp. Med."},{"key":"ref_40","first-page":"387","article-title":"Comparison of plasma corticosterone concentration, muscle fibre diameter, and apoptotic markers between normal and pale, soft, exudative (PSE) turkey breast muscles","volume":"74","author":"Wojtysiak","year":"2018","journal-title":"Med. Wet."},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"CIE (1978). Recommendations on Uniform Color Spaces-Color Difference Equations, Psychometric Color Terms, Bureau Central de la Commission Internationale de l\u2019Eclairage. Supplement No. 2 to CIE Publication No. 15 (E-1.3.1.).","DOI":"10.1002\/j.1520-6378.1977.tb00102.x"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1016\/S0315-5463(82)72308-9","article-title":"Development of pink color in cooked pork","volume":"15","author":"Howe","year":"1982","journal-title":"Can. Inst. Food Sci. Technol."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"1197","DOI":"10.1515\/aoas-2017-0009","article-title":"Effect of organic production system on the performance and meat quality of two purebred slow-growing chicken breeds","volume":"17","author":"Skomorucha","year":"2017","journal-title":"Ann. Anim. Sci."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"131","DOI":"10.1016\/j.meatsci.2018.12.005","article-title":"Fatty acid composition, cholesterol content and lipid oxidation indices ofintramuscular fat from skeletal muscles of beaver (Castor fiber L.)","volume":"150","author":"Domaradzki","year":"2019","journal-title":"Meat Sci."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"364","DOI":"10.1016\/S0022-2275(20)36896-6","article-title":"Determination of cholesterol using o-phthalaldehyde","volume":"14","author":"Rudel","year":"1973","journal-title":"J. Lipid Res."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"491","DOI":"10.3382\/ps\/pew301","article-title":"Effect of caponization on performance and quality characteristics of long bones in Polbar chickens","volume":"96","author":"Tomaszewska","year":"2017","journal-title":"Poult. Sci."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"403","DOI":"10.2478\/aoas-2019-0003","article-title":"Bone homeostasis in experimental fumonisins intoxication of rats","volume":"18","author":"Rudyk","year":"2019","journal-title":"Ann. Anim. Sci."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"447","DOI":"10.1007\/BF01002772","article-title":"Picrosirus staining plus polarization microscopy, a specific method for collagen detection in tissue sections","volume":"11","author":"Junqueira","year":"1979","journal-title":"Histochem. J."},{"key":"ref_49","doi-asserted-by":"crossref","unstructured":"Blicharski, T., Tomaszewska, E., Dobrowolski, P., Hu\u0142as-Stasiak, M., and Muszy\u0144ski, S. (2017). A metabolite of leucine (\u03b2-hydroxy-\u03b2-methylbutyrate) given to sows during pregnancy alters bone development of their newborn offspring by hormonal modulation. PLoS ONE, 12.","DOI":"10.1371\/journal.pone.0179693"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"341","DOI":"10.1177\/0023677217738268","article-title":"On determining sample size in experiments involving laboratory animals","volume":"52","author":"Festing","year":"2018","journal-title":"Lab. Anim."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"61","DOI":"10.17221\/7230-CJAS","article-title":"Bones quality indices in laying hens fed diets with a high level of DDGS and supplemented with selected feed additives","volume":"59","year":"2014","journal-title":"Czech J. Anim. Sci."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"4824","DOI":"10.1021\/jf034296e","article-title":"Effect of red mold rice supplements on serum and egg yolk cholesterol levels of laying hens","volume":"51","author":"Wang","year":"2003","journal-title":"J. Agric. Food Chem."},{"key":"ref_53","doi-asserted-by":"crossref","unstructured":"Popescu, R.G., Voicu, S.N., Piracalabioru, G.G., Ciceu, A., Gharbia, S., Hermenean, A., Gogergescu, S.E., Panaite, T.D., and Dinischotu, A. (2020). Effects of dietary inclusion of bilberry and walnut leaves powder on the digestive performances and health of Tetra SL laying hens. Animals, 10.","DOI":"10.3390\/ani10050823"},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"2","DOI":"10.1037\/a0024338","article-title":"Effect size estimates: Current use, calculations, and interpretation","volume":"141","author":"Fritz","year":"2012","journal-title":"J. Exp. Psychol. Gen."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"488","DOI":"10.1093\/ps\/86.3.488","article-title":"Supplementation of glutamine and vitamin E on the morphometry of the intestinal mucosa in broiler chickens","volume":"86","author":"Murakami","year":"2007","journal-title":"Poult. Sci."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"243","DOI":"10.1590\/S1516-635X2006000400007","article-title":"Influence of glutamine and vitamin E on the performance and the immune responses of broiler chickens","volume":"8","author":"Sakamoto","year":"2006","journal-title":"Braz. J. Poult. Sci."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"283","DOI":"10.1093\/ps\/84.2.283","article-title":"Impact of glutamine and oasis hatchling supplement on growth performance, small intestinal morphology, and immune response of broilers vaccinated and challenged with Eimeria maxima","volume":"84","author":"Yi","year":"2005","journal-title":"Poult. Sci."},{"key":"ref_58","unstructured":"Bartell, S.M. (2006). The Effect of Supplemental Glutamine on Growth Performance, Development of the Gastrointestinal Tract, and Immune Response of Broiler Chicks. [Master\u2019s Thesis, University of Georgia]. Available online: https:\/\/getd.libs.uga.edu\/pdfs\/bartell_shoshana_m_200605_ms.pdf."},{"key":"ref_59","first-page":"547","article-title":"Postnatal administration of 2-oxoglutaric acid improves articular and growth plate cartilages and bone tissue morphology in pigs prenatally treated with dexamethasone","volume":"63","author":"Tomaszewska","year":"2012","journal-title":"J. Physiol. Pharmacol."},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"483","DOI":"10.3109\/03008207.2015.1069822","article-title":"Effects of 2-oxoglutaric acid on bone morphometry, densitometry, mechanics, and immunohistochemistry in 9-month-old boars with prenatal dexamethasone-induced osteopenia","volume":"56","author":"Tomaszewska","year":"2015","journal-title":"Connect. Tissue Res."},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"1359","DOI":"10.1002\/jmor.21037","article-title":"Morphological bases for intestinal paracellular absorption in bats and rodents","volume":"280","author":"Brun","year":"2019","journal-title":"J. Morphol."},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"1757","DOI":"10.3382\/ps\/pex349","article-title":"Comparison of two methods for determination of intestinal villus to crypt ratios and documentation of early age-associated ratio changes in broiler chickens","volume":"97","author":"Wilson","year":"2018","journal-title":"Poult. Sci."},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"322","DOI":"10.1590\/0103-9016-2015-0114","article-title":"Effects of glutamine on performance and intestinal mucosa morphometry of broiler chickens vaccinated against coccidiosis","volume":"73","author":"Luquetti","year":"2016","journal-title":"Sci. Agric."},{"key":"ref_64","doi-asserted-by":"crossref","first-page":"331","DOI":"10.1007\/s11259-006-3236-1","article-title":"Can nutraceuticals affect the structure of intestinal mucosa? Qualitative and quantitative microanatomy in L-glutamine diet-supplemented weaning piglets","volume":"30","author":"Domeneghini","year":"2006","journal-title":"Vet. Res. Commun."},{"key":"ref_65","doi-asserted-by":"crossref","unstructured":"Chen, Y., Tsai, Y.H., Tseng, B.J., and Tseng, S.H. (2019). Influence of growth hormone and glutamine on intestinal stem cells: A narrative review. Nutrients, 11.","DOI":"10.3390\/nu11081941"},{"key":"ref_66","doi-asserted-by":"crossref","first-page":"190","DOI":"10.1016\/j.nut.2011.05.010","article-title":"Postnatal administration of 2-oxoglutaric acid improves the intestinal barrier affected by the prenatal action of dexamethasone in pigs","volume":"28","author":"Tomaszewska","year":"2012","journal-title":"Nutrition"},{"key":"ref_67","unstructured":"Konturek, S. (1985). Physiology of the Gastrointestinal Tract, PZWL. [2nd ed.]."},{"key":"ref_68","first-page":"205","article-title":"Effect of simultaneous versus apart administration of dexamethasone and alpha-ketoglutarate on growth hormone, cortisol and insulin-like growth factor-I in piglets","volume":"50","year":"2006","journal-title":"Bull. Vet. Inst. Pulawy"},{"key":"ref_69","doi-asserted-by":"crossref","first-page":"2062","DOI":"10.3382\/ps.0632062","article-title":"Hormones and growth in poultry","volume":"63","author":"Scanes","year":"1984","journal-title":"Poult. Sci."},{"key":"ref_70","doi-asserted-by":"crossref","first-page":"163","DOI":"10.1080\/00071667908416564","article-title":"Variations in plasma growth hormone concentrations in laying hens","volume":"20","author":"Harvey","year":"1979","journal-title":"Br. Poult. Sci."},{"key":"ref_71","doi-asserted-by":"crossref","first-page":"1294","DOI":"10.5713\/ajas.15.0674","article-title":"Peripheral insulin doesn\u2019t alter appetite of broiler chicks","volume":"29","author":"Liu","year":"2016","journal-title":"Asian-Australas. J. Anim. Sci."},{"key":"ref_72","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1016\/j.physbeh.2011.02.008","article-title":"Comparisons of insulin related parameters in commercial-type chicks: Evidence for insulin resistance in broiler chicks","volume":"103","author":"Shiraishi","year":"2011","journal-title":"Physiol. Behav."},{"key":"ref_73","doi-asserted-by":"crossref","first-page":"153","DOI":"10.1016\/0021-9150(73)90126-3","article-title":"The relationship of arterial disease and glucagon metabolism in insulin-treated chickens","volume":"18","author":"Stout","year":"1973","journal-title":"Atherosclerosis"},{"key":"ref_74","doi-asserted-by":"crossref","first-page":"1694","DOI":"10.1093\/ps\/81.11.1694","article-title":"Effects of glucagon and insulin on plasma glucose, triglyceride, and triglyceride-rich lipoprotein concentrations in laying hens fed diets containing different types of fats","volume":"81","author":"Pal","year":"2002","journal-title":"Poult. Sci."},{"key":"ref_75","doi-asserted-by":"crossref","first-page":"52","DOI":"10.1016\/j.ygcen.2008.10.016","article-title":"Insulin signaling in chicken liver and muscle","volume":"163","author":"Dupont","year":"2009","journal-title":"Gen. Comp. Endocrinol."},{"key":"ref_76","doi-asserted-by":"crossref","first-page":"261","DOI":"10.1515\/aoas-2017-0034","article-title":"Meat quality of poulards obtained from three conserved breeds of hens","volume":"18","author":"Obrzut","year":"2018","journal-title":"Ann. Anim. Sci."},{"key":"ref_77","doi-asserted-by":"crossref","first-page":"247","DOI":"10.2478\/aoas-2014-0082","article-title":"Effect of breed and production system on physicochemical characteristics of meat from multi-purpose hens","volume":"15","author":"Krawczyk","year":"2015","journal-title":"Ann. Anim. Sci."},{"key":"ref_78","first-page":"561","article-title":"Total cholesterol, glucose and electrolytes in piglets\u2019 serum after alpha-ketoglutarate (AKG) and dexamethasone treatment during prenatal and neonatal life","volume":"50","author":"Tatara","year":"2006","journal-title":"Bull. Vet. Inst. Pulawy"},{"key":"ref_79","doi-asserted-by":"crossref","first-page":"961","DOI":"10.2478\/aoas-2020-0019","article-title":"Algal oil as source of polyunsaturated fatty acids in laying hens nutrition: Effect on egg performance, egg quality indices and fatty acid composition of egg yolk lipids","volume":"20","author":"Szczurek","year":"2020","journal-title":"Ann. Anim. Sci."},{"key":"ref_80","doi-asserted-by":"crossref","first-page":"1009","DOI":"10.2478\/aoas-2019-0028","article-title":"Selected physical and chemical characteristics of eggs laid by hens fed diets with different levels of hybrid rye","volume":"19","author":"Pasternak","year":"2019","journal-title":"Ann. Anim. Sci."},{"key":"ref_81","first-page":"205","article-title":"Microstructure and technological meat quality of geese from conservation flock and commercial hybrids","volume":"9","author":"Wojtysiak","year":"2009","journal-title":"Ann. Anim. Sci."},{"key":"ref_82","first-page":"85","article-title":"Metabolic status and ghrelin regulate plasma levels and release of ovarian hormones in layer chicks","volume":"66","author":"Sirotkin","year":"2016","journal-title":"Physiol. Res."},{"key":"ref_83","doi-asserted-by":"crossref","first-page":"749401","DOI":"10.1155\/2010\/749401","article-title":"The avian proghrelin system","volume":"2010","author":"Richards","year":"2010","journal-title":"Int. J. Pept."},{"key":"ref_84","doi-asserted-by":"crossref","first-page":"819","DOI":"10.1016\/j.tem.2019.07.007","article-title":"Avian leptin: Bird\u2019s-eye view of the evolution of vertebrate energy-balance control","volume":"30","author":"Seroussi","year":"2019","journal-title":"Trends Endocrinol. Metab."},{"key":"ref_85","first-page":"13","article-title":"Chronic administration of leptin in Asian Blue Quail","volume":"305","author":"Silverin","year":"2006","journal-title":"J. Exp. Zool. A Comp. Exp. Biol."},{"key":"ref_86","doi-asserted-by":"crossref","first-page":"252","DOI":"10.1016\/j.tvjl.2013.07.017","article-title":"Effects of dietary energy and calcium levels on performance, egg shell quality and bone metabolism in hens","volume":"198","author":"Jiang","year":"2013","journal-title":"Vet. J."},{"key":"ref_87","doi-asserted-by":"crossref","first-page":"289","DOI":"10.1007\/s00441-010-1086-1","article-title":"Osteoblast physiology in normal and pathological condition","volume":"342","author":"Neve","year":"2011","journal-title":"Cell Tissue Res."},{"key":"ref_88","doi-asserted-by":"crossref","first-page":"177","DOI":"10.1017\/S0029665108007015","article-title":"Nutritional factors affecting poultry bone health","volume":"67","author":"Fleming","year":"2008","journal-title":"Proc. Nutr. Soc."},{"key":"ref_89","doi-asserted-by":"crossref","unstructured":"Johnsson, M., Jonsson, K.B., Andersson, L., Jensen, P., and Wright, D. (2015). Genetic regulation of bone metabolism in the chicken: Similarities and differences to mammalian systems. PLoS Genet., 11.","DOI":"10.1371\/journal.pgen.1005250"},{"key":"ref_90","unstructured":"Scanes, C.G. (2015). Sturkie\u2019s Avian Physiology, Academic Press. [6th ed.]."},{"key":"ref_91","doi-asserted-by":"crossref","first-page":"781","DOI":"10.2478\/aoas-2018-0017","article-title":"The influence of selected feed additives on mineral utilisation and bone characteristics in laying hens","volume":"18","author":"Szczurek","year":"2018","journal-title":"Ann. Anim. Sci."},{"key":"ref_92","doi-asserted-by":"crossref","first-page":"389","DOI":"10.1007\/s10735-019-09835-x","article-title":"Osteoclastogenesis from bone marrow cells during estrogen-induced medullary bone formation in Japanese quails","volume":"50","author":"Hiyama","year":"2019","journal-title":"J. Mol. Histol."},{"key":"ref_93","doi-asserted-by":"crossref","first-page":"136","DOI":"10.1016\/j.mehy.2018.05.006","article-title":"Fractal dimension: A complementary diagnostic indicator of osteoporosis to bone mineral density","volume":"116","author":"Chen","year":"2018","journal-title":"Med. Hypotheses"}],"container-title":["Animals"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-2615\/10\/12\/2420\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T10:46:24Z","timestamp":1760179584000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-2615\/10\/12\/2420"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,12,17]]},"references-count":93,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2020,12]]}},"alternative-id":["ani10122420"],"URL":"https:\/\/doi.org\/10.3390\/ani10122420","relation":{},"ISSN":["2076-2615"],"issn-type":[{"value":"2076-2615","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,12,17]]}}}