{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,4]],"date-time":"2026-04-04T06:31:30Z","timestamp":1775284290702,"version":"3.50.1"},"reference-count":52,"publisher":"Cambridge University Press (CUP)","issue":"1","license":[{"start":{"date-parts":[[2023,7,20]],"date-time":"2023-07-20T00:00:00Z","timestamp":1689811200000},"content-version":"unspecified","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["cambridge.org"],"crossmark-restriction":true},"short-container-title":["Br J Nutr"],"published-print":{"date-parts":[[2024,1,14]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>Reducing dietary crude protein (CP) concentration while maintaining adequate amino acid (AA) supply by free AA inclusion can contribute to attenuate the negative environmental effects of animal farming. This study investigated upper limits of dietary free AA inclusions without undesirable effects including the dependence on asparagine (Asn) and glutamine (Gln) supply. Ten broilers were allocated to sixty-three metabolism units each and offered nine experimental diets from day (d) 7\u201321 (<jats:italic>n<\/jats:italic> 7). One diet (167 g CP\/kg) contained 80 g soya protein isolate (SPI)\/kg. In the other diets, 25, 50, 75 and 100 % of the digestible AA from SPI were substituted with free AA. Digestible Asn+aspartic acid (Asp) and Gln+glutamic acid (Glu) were substituted with Asp\/Glu or 50\/50 mixes of Asp\/Asn and Glu\/Gln, respectively. Total excreta were collected from d 11\u201314 and from d 18\u201321. Growth and nitrogen accretion were unaffected by 25 and 50 % substitution without and with free Asn\/Gln, respectively, but decreased at higher substitution (<jats:italic>P<\/jats:italic> \u2264 0\u00b7024). Circulating concentrations of Asp, Glu and Gln were unaffected by treatment, while Asn decreased at substitution higher than 50 % when Asn\/Gln were not provided (<jats:italic>P<\/jats:italic> \u2264 0\u00b7005). Blood gas analysis on d 21 indicated a compensated metabolic acidosis at substitution higher than 50 and 75 % without and with free Asn\/Gln, respectively (<jats:italic>P<\/jats:italic> \u2264 0\u00b7017). Results suggest that adding Asn\/Gln increased an upper limit for proportion of dietary free AA from 10 to 19 % of dietary CP and enabled higher free AA inclusion without affecting the acid\u2013base balance.<\/jats:p>","DOI":"10.1017\/s0007114523001617","type":"journal-article","created":{"date-parts":[[2023,7,20]],"date-time":"2023-07-20T07:31:28Z","timestamp":1689838288000},"page":"41-53","update-policy":"https:\/\/doi.org\/10.1017\/policypage","source":"Crossref","is-referenced-by-count":11,"title":["The influence of substituting dietary peptide-bound with free amino acids on nitrogen metabolism and acid\u2013base balance of broiler chickens depends on asparagine and glutamine supply"],"prefix":"10.1017","volume":"131","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5408-2177","authenticated-orcid":false,"given":"Ahmad","family":"Ibrahim","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9041-3452","authenticated-orcid":false,"given":"\u00c1kos","family":"Ken\u00e9z","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3156-7889","authenticated-orcid":false,"given":"Markus","family":"Rodehutscord","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7823-0293","authenticated-orcid":false,"given":"Wolfgang","family":"Siegert","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"56","published-online":{"date-parts":[[2023,7,20]]},"reference":[{"key":"S0007114523001617_ref8","doi-asserted-by":"publisher","DOI":"10.1016\/j.animal.2022.100684"},{"key":"S0007114523001617_ref38","doi-asserted-by":"publisher","DOI":"10.3382\/ps.0681385"},{"key":"S0007114523001617_ref19","doi-asserted-by":"publisher","DOI":"10.1016\/j.psj.2020.09.003"},{"key":"S0007114523001617_ref28","doi-asserted-by":"publisher","DOI":"10.3382\/ps\/pev109"},{"key":"S0007114523001617_ref17","doi-asserted-by":"publisher","DOI":"10.1093\/ps\/85.2.288"},{"key":"S0007114523001617_ref51","doi-asserted-by":"publisher","DOI":"10.1111\/j.1463-1326.2009.01054.x"},{"key":"S0007114523001617_ref47","first-page":"47","article-title":"Acid-Base status in the avian patient using a portable point-of-care analyzer","volume":"16","author":"Montesinos","year":"2013","journal-title":"Vet Clin N Am: Exot Anim Pract"},{"key":"S0007114523001617_ref20","doi-asserted-by":"publisher","DOI":"10.1079\/9780851996547.0015"},{"key":"S0007114523001617_ref2","doi-asserted-by":"publisher","DOI":"10.1079\/9780851996547.0041"},{"key":"S0007114523001617_ref11","doi-asserted-by":"publisher","DOI":"10.1007\/s003940070001"},{"key":"S0007114523001617_ref39","doi-asserted-by":"publisher","DOI":"10.1079\/BJN19890065"},{"key":"S0007114523001617_ref24","doi-asserted-by":"publisher","DOI":"10.1093\/jn\/nxz022"},{"key":"S0007114523001617_ref3","doi-asserted-by":"publisher","DOI":"10.1007\/s00726-009-0269-0"},{"key":"S0007114523001617_ref7","doi-asserted-by":"publisher","DOI":"10.5713\/ajas.1999.939"},{"key":"S0007114523001617_ref18","doi-asserted-by":"publisher","DOI":"10.2527\/jas.2010-3757"},{"key":"S0007114523001617_ref16","doi-asserted-by":"publisher","DOI":"10.1080\/00071668.2016.1163523"},{"key":"S0007114523001617_ref10","doi-asserted-by":"publisher","DOI":"10.1111\/j.1439-0396.2008.00820.x"},{"key":"S0007114523001617_ref23","volume-title":"Empfehlungen zur Energie- und N\u00e4hrstoffversorgung der Legehennen und Masth\u00fchner (Broiler)","year":"1999"},{"key":"S0007114523001617_ref1","doi-asserted-by":"publisher","DOI":"10.1080\/00071668.2019.1622081"},{"key":"S0007114523001617_ref32","doi-asserted-by":"publisher","DOI":"10.1016\/j.domaniend.2007.05.002"},{"key":"S0007114523001617_ref34","doi-asserted-by":"publisher","DOI":"10.1042\/bj1780589"},{"key":"S0007114523001617_ref35","doi-asserted-by":"publisher","DOI":"10.1093\/jas\/skac053"},{"key":"S0007114523001617_ref12","doi-asserted-by":"publisher","DOI":"10.1177\/0148607189013004382"},{"key":"S0007114523001617_ref25","doi-asserted-by":"publisher","DOI":"10.1080\/17450390500217058"},{"key":"S0007114523001617_ref29","doi-asserted-by":"publisher","DOI":"10.1080\/17450390500147925"},{"key":"S0007114523001617_ref36","doi-asserted-by":"publisher","DOI":"10.1016\/B978-012747605-6\/50012-2"},{"key":"S0007114523001617_ref21","doi-asserted-by":"publisher","DOI":"10.2527\/1990.682398x"},{"key":"S0007114523001617_ref6","doi-asserted-by":"crossref","first-page":"127","DOI":"10.1071\/A97028","article-title":"Effects on growth rate and utilisation of amino acids in weaner pigs fed diets containing whole proteins and free amino acids in combination with different energy sources","volume":"49","author":"Officer","year":"1998","journal-title":"Aust J Agric Res"},{"key":"S0007114523001617_ref30","unstructured":"30. 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