{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T19:05:52Z","timestamp":1791313552407,"version":"4.3.1"},"reference-count":44,"publisher":"Oxford University Press (OUP)","issue":"8","license":[{"start":{"date-parts":[[2020,6,25]],"date-time":"2020-06-25T00:00:00Z","timestamp":1593043200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/journals\/pages\/open_access\/funder_policies\/chorus\/standard_publication_model"}],"funder":[{"DOI":"10.13039\/501100000978","name":"Australian Pork Limited","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100000978","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2020,8,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:p>Dietary tryptophan (Trp) is a precursor for serotonin, a neuromediator involved in stress responses. Tryptophan competes with other large neutral amino acids (LNAA: tyrosine, isoleucine, leucine, valine, and phenylalanine) to cross the blood\u2013brain barrier; therefore, the regulation of circulating LNAA can influence Trp availability in the cortex and serotonin biosynthesis. The hypothesis examined in this study was that increased supplementation of dietary Trp and a reduction in LNAA for weaned pigs experimentally infected with enterotoxigenic Escherichia coli (ETEC; F4) will increase Trp availability in plasma and reduce indices of the stress response, which will translate to reduced production losses. At 21 \u00b1 3 d of age (mean \u00b1 SEM), 96 male pigs (Large White \u00d7 Landrace) weighing 6.3 \u00b1 0.98 kg (mean \u00b1 SEM) were individually penned and allocated to a 4 \u00d7 2 factorial arrangement of treatments, with respective factors being 1) four dietary standardized ileal digestible (SID) Trp and LNAA contents, being HTrpHLNAA (Low Trp-High LNAA; 0.24% SID Trp: 5.4% SID LNAA), HTrpHLNAA (Low Trp-Low LNAA; 0.24% SID Trp: 4.6% SID LNAA), HTrpHLNAA (High Trp-High LNAA; 0.34% SID Trp: 5.4% SID LNAA), and HTrpHLNAA (High Trp-Low LNAA; 0.34% SID Trp: 4.6% SID LNAA), and 2) without\/with ETEC infection. Pigs were orally infected with 0.8 mL (3.6 \u00d7 109 CFU\/mL) ETEC at days 7 and 8 after weaning. Pigs fed diets high in Trp irrespective of the level of LNAA (HTrpHLNAA and HTrpLLNAA) had higher plasma Trp concentrations (P &amp;lt; 0.001) and a Trp:LNAA ratio (P &amp;lt; 0.001) before infection and 6 d after infection. Following infection, noninfected pigs had higher plasma Trp (P = 0.03) and a Trp:LNAA ratio (P = 0.004) compared with pigs infected with ETEC. Plasma cortisol levels after infection were higher in ETEC-infected pigs (P = 0.05) and altering dietary Trp and LNAA concentrations did not influence (P &amp;gt; 0.05) plasma cortisol. Pigs fed diet HTrpLLNAA had higher serum serotonin levels 24 h after infection (P = 0.02) compared with pigs fed diets LTrpLLNAA and HTrpHLNAA. Similarly, pigs fed diet HTrpLLNAA had a higher (P = 0.02) average daily gain during the 3-wk study. Overall, average daily feed intake tended to be higher in pigs fed an HTrpLLNAA diet compared with the other diets (P = 0.08). These results suggest that the increased supplementation of dietary Trp with reduced LNAA increased circulating Trp levels that, in turn, likely caused higher serum serotonin levels, irrespective of infection with ETEC, and improved aspects of post-weaning performance.<\/jats:p>","DOI":"10.1093\/jas\/skaa190","type":"journal-article","created":{"date-parts":[[2020,6,25]],"date-time":"2020-06-25T11:03:45Z","timestamp":1593083025000},"source":"Crossref","is-referenced-by-count":12,"title":["Increasing dietary tryptophan in conjunction with decreasing other large neutral amino acids increases weight gain and feed intake in weaner pigs regardless of experimental infection with enterotoxigenic Escherichia coli"],"prefix":"10.1093","volume":"98","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4902-6442","authenticated-orcid":false,"given":"Samantha O","family":"Sterndale","sequence":"first","affiliation":[{"name":"Agricultural Sciences, College of Science, Health, Engineering and Education, Murdoch University, Murdoch WA, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4634-5819","authenticated-orcid":false,"given":"David W","family":"Miller","sequence":"additional","affiliation":[{"name":"Agricultural Sciences, College of Science, Health, Engineering and Education, Murdoch University, Murdoch WA, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Josie P","family":"Mansfield","sequence":"additional","affiliation":[{"name":"Agricultural Sciences, College of Science, Health, Engineering and Education, Murdoch University, Murdoch WA, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jae C","family":"Kim","sequence":"additional","affiliation":[{"name":"Agricultural Sciences, College of Science, Health, Engineering and Education, Murdoch University, Murdoch WA, Australia"},{"name":"AB Vista Asia Pte. Ltd., The Mezzo, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"John R","family":"Pluske","sequence":"additional","affiliation":[{"name":"Agricultural Sciences, College of Science, Health, Engineering and Education, Murdoch University, Murdoch WA, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2020,6,25]]},"reference":[{"key":"2020081201563016300_CIT0001","volume-title":"AMSA meat color measurement guidelines","author":"AMSA","year":"2012"},{"key":"2020081201563016300_CIT0002","doi-asserted-by":"crossref","first-page":"299","DOI":"10.1016\/0739-7240(89)90024-6","article-title":"Altered adrenocortical response to acute stressors or ACTH(1-24) in intensively housed pigs","volume":"6","author":"von Borell","year":"1989","journal-title":"Domest. Anim. Endocrinol"},{"issue":"5","key":"2020081201563016300_CIT0003","doi-asserted-by":"crossref","first-page":"935","DOI":"10.1071\/AN15289","article-title":"Pigs experimentally infected with an enterotoxigenic strain of Escherichia coli have improved feed efficiency and indicators of inflammation with dietary supplementation of tryptophan and methionine in the immediate post-weaning period","volume":"57(","author":"Capozzalo","year":"2017","journal-title":"Anim. Prod. Sci"},{"key":"2020081201563016300_CIT0004","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1080\/1745039X.2014.995972","article-title":"Effect of increasing the dietary tryptophan to lysine ratio on plasma levels of tryptophan, kynurenine and urea and on production traits in weaner pigs experimentally infected with an enterotoxigenic strain of Escherichia coli","volume":"69","author":"Capozzalo","year":"2015","journal-title":"Arch. Anim. Nutr"},{"key":"2020081201563016300_CIT0005","doi-asserted-by":"crossref","first-page":"118","DOI":"10.1016\/j.anifeedsci.2017.03.004","article-title":"Determination of the optimum standardised ileal digestible sulphur amino acids to lysine ratio in weaned pigs challenged with enterotoxigenic Escherichia coli","volume":"227","author":"Capozzalo","year":"2017","journal-title":"Anim. Feed Sci. Technol"},{"key":"2020081201563016300_CIT0006","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1016\/j.tvjl.2010.04.009","article-title":"Acute phase proteins: biomarkers of infection and inflammation in veterinary medicine","volume":"185","author":"Eckersall","year":"2010","journal-title":"Vet. J"},{"issue":"3","key":"2020081201563016300_CIT0007","doi-asserted-by":"crossref","first-page":"117","DOI":"10.1007\/BF02600369","article-title":"An automated biochemical assay for haptoglobin: prevention of interference from albumin","volume":"9","author":"Eckersall","year":"1999","journal-title":"Comp. Heamatol. Int"},{"key":"2020081201563016300_CIT0008","doi-asserted-by":"crossref","first-page":"147","DOI":"10.1080\/10495398.2011.653462","article-title":"Analysis of association between the MUC4 g.8227C&gt;G polymorphism and production traits in Italian heavy pigs using a selective genotyping approach","volume":"23","author":"Fontanesi","year":"2012","journal-title":"Anim. Biotechnol"},{"key":"2020081201563016300_CIT0009","doi-asserted-by":"crossref","first-page":"2700","DOI":"10.2527\/1996.74112700x","article-title":"Growth performance and brain neurotransmitters in pigs as affected by tryptophan, protein, and sex","volume":"74","author":"Henry","year":"1996","journal-title":"J. Anim. Sci"},{"key":"2020081201563016300_CIT0010","doi-asserted-by":"crossref","first-page":"2833","DOI":"10.2527\/jas.2008-1274","article-title":"Feeding a diet with decreased protein content reduces indices of protein fermentation and the incidence of postweaning diarrhea in weaned pigs challenged with an enterotoxigenic strain of Escherichia coli","volume":"87","author":"Heo","year":"2009","journal-title":"J. Anim. Sci"},{"issue":"2","key":"2020081201563016300_CIT0011","doi-asserted-by":"crossref","first-page":"207","DOI":"10.1111\/j.1439-0396.2012.01284.x","article-title":"Gastrointestinal health and function in weaned pigs: a review of feeding strategies to control post-weaning diarrhoea without using in-feed antimicrobial compounds","volume":"97","author":"Heo","year":"2013","journal-title":"J. Anim. Physiol. Anim. Nutr"},{"key":"2020081201563016300_CIT0012","doi-asserted-by":"crossref","first-page":"474","DOI":"10.2527\/1998.762474x","article-title":"Behavioral, endocrine, immune, and performance measures for pigs exposed to acute stress","volume":"76","author":"Hicks","year":"1998","journal-title":"J. Anim. Sci"},{"key":"2020081201563016300_CIT0013","doi-asserted-by":"crossref","first-page":"3303","DOI":"10.2527\/jas.2007-0105","article-title":"Effect of dietary protein content on ileal amino acid digestibility, growth performance, and formation of microbial metabolites in ileal and cecal digesta of early-weaned pigs","volume":"85","author":"Htoo","year":"2007","journal-title":"J. Anim. Sci"},{"issue":"Pt 4","key":"2020081201563016300_CIT0014","doi-asserted-by":"crossref","first-page":"273","DOI":"10.1099\/jmm.0.05323-0","article-title":"Experimental swine dysentery: comparison between infection models","volume":"53","author":"Jacobson","year":"2004","journal-title":"J. Med. Microbiol"},{"key":"2020081201563016300_CIT0015","doi-asserted-by":"crossref","first-page":"243","DOI":"10.1016\/j.vetmic.2006.01.002","article-title":"Experimental infection with Escherichia coli O149:F4ac in weaned piglets","volume":"115","author":"Jensen","year":"2006","journal-title":"Vet. Microbiol"},{"key":"2020081201563016300_CIT0016","doi-asserted-by":"crossref","first-page":"475","DOI":"10.1093\/ps\/77.3.475","article-title":"Fluorometric analysis of 2-thiobarbituric acid reactive substances in Turkey","volume":"77","author":"Jo","year":"1998","journal-title":"Poult. Sci"},{"key":"2020081201563016300_CIT0017","first-page":"591","article-title":"Stress and the gut: pathophysiology, clinical consequences, diagnostic approach and treatment options","volume":"62","author":"Konturek","year":"2011","journal-title":"J. Physiol. Pharmacol"},{"key":"2020081201563016300_CIT0018","doi-asserted-by":"crossref","first-page":"963","DOI":"10.2527\/2006.844963x","article-title":"Effects of supplemental","volume":"84","author":"Koopmans","year":"2006","journal-title":"J. Anim. Sci"},{"key":"2020081201563016300_CIT0019","doi-asserted-by":"crossref","first-page":"4282","DOI":"10.1093\/jas\/skz259","article-title":"Excess dietary leucine in diets for growing pigs reduces growth performance, biological value of protein, protein retention, and serotonin synthesis1","volume":"97","author":"Kwon","year":"2019","journal-title":"J. Anim. Sci"},{"issue":"1","key":"2020081201563016300_CIT0020","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1016\/j.livsci.2007.07.002","article-title":"Biological roles of tryptophan and its metabolism: potential implications for pig feeding","volume":"112","author":"Le Floc\u2019h","year":"2007","journal-title":"Livest. Sci"},{"key":"2020081201563016300_CIT0021","doi-asserted-by":"crossref","first-page":"212","DOI":"10.2527\/2006.841212x","article-title":"Use of supplementary tryptophan to modify the behavior of pigs","volume":"84","author":"Li","year":"2006","journal-title":"J. Anim. Sci"},{"key":"2020081201563016300_CIT0022","doi-asserted-by":"crossref","first-page":"47","DOI":"10.1124\/jpet.107.132670","article-title":"Discovery and characterization of novel tryptophan hydroxylase inhibitors that selectively inhibit serotonin synthesis in the gastrointestinal tract","volume":"325","author":"Liu","year":"2008","journal-title":"J. Pharmacol. Exp. Ther"},{"key":"2020081201563016300_CIT0023","doi-asserted-by":"crossref","first-page":"247","DOI":"10.1007\/s12017-008-8039-9","article-title":"Dietary amino acids and brain serotonin function; implications for stress-related affective changes","volume":"10","author":"Markus","year":"2008","journal-title":"Neuromolecular Med"},{"issue":"8","key":"2020081201563016300_CIT0024","doi-asserted-by":"crossref","first-page":"473","DOI":"10.1038\/nrgastro.2013.105","article-title":"Serotonin signalling in the gut\u2014functions, dysfunctions and therapeutic targets","volume":"10","author":"Mawe","year":"2013","journal-title":"Nat. Rev. Gastro. Hepat"},{"key":"2020081201563016300_CIT0025","doi-asserted-by":"crossref","first-page":"166","DOI":"10.3389\/fimmu.2019.00166","article-title":"Structure-function relationships of C-reactive protein in bacterial infection","volume":"10","author":"Ngwa","year":"2019","journal-title":"Front. Immunol"},{"key":"2020081201563016300_CIT0026","volume-title":"National Research Council. Nutrient requirements of swine","author":"NRC","year":"2012"},{"key":"2020081201563016300_CIT0027","doi-asserted-by":"crossref","first-page":"E622","DOI":"10.1152\/ajpendo.00187.2004","article-title":"Na+-dependent neutral amino acid transporters A, ASC, and N of the blood-brain barrier: mechanisms for neutral amino acid removal","volume":"287","author":"O\u2019Kane","year":"2004","journal-title":"Am. J. Physiol. Endocrinol. Metab"},{"key":"2020081201563016300_CIT0028","doi-asserted-by":"crossref","first-page":"1805","DOI":"10.1172\/JCI200318921","article-title":"C-reactive protein: a critical update","volume":"111","author":"Pepys","year":"2003","journal-title":"J. Clin. Invest"},{"key":"2020081201563016300_CIT0029","doi-asserted-by":"crossref","first-page":"187","DOI":"10.1016\/j.aninu.2017.12.004","article-title":"Gastrointestinal tract (gut) health in the young pig","volume":"4","author":"Pluske","year":"2018","journal-title":"Anim. Nutr"},{"issue":"2","key":"2020081201563016300_CIT0030","doi-asserted-by":"crossref","first-page":"98","DOI":"10.1016\/j.applanim.2009.11.015","article-title":"Aggression in replacement grower and finisher gilts fed a short-term high-tryptophan diet and the effect of long-term human\u2013animal interaction","volume":"122","author":"Poletto","year":"2010","journal-title":"Appl. Anim. Behav. Sci"},{"key":"2020081201563016300_CIT0031","doi-asserted-by":"crossref","first-page":"157","DOI":"10.1016\/S0301-6226(97)00006-7","article-title":"The effect of housing conditions and social environment immediately after weaning on the agonistic behaviour, neutrophil\/lymphocyte ratio, and plasma glucose level in pigs","volume":"48","author":"Puppe","year":"1997","journal-title":"Livest. Prod. Sci"},{"key":"2020081201563016300_CIT0032","doi-asserted-by":"crossref","first-page":"729","DOI":"10.1007\/978-1-4615-4709-9_95","volume-title":"Physiological roles of tryptophan in pig nutrition, tryptophan, serotonin, and melatonin","author":"S\u00e8ve","year":"1999"},{"key":"2020081201563016300_CIT0033","doi-asserted-by":"crossref","first-page":"245","DOI":"10.1016\/j.anifeedsci.2015.06.020","article-title":"Effects of short term supplementation of l-tryptophan and reducing large neutral amino acid along with","volume":"207","author":"Shen","year":"2015","journal-title":"Anim. Feed Sci. Technol"},{"key":"2020081201563016300_CIT0034","doi-asserted-by":"crossref","first-page":"2264","DOI":"10.2527\/jas.2011-4203","article-title":"Effects of increasing tryptophan intake on growth and physiological changes in nursery pigs","volume":"90","author":"Shen","year":"2012","journal-title":"J. Anim. Sci"},{"key":"2020081201563016300_CIT0035","doi-asserted-by":"crossref","first-page":"1540","DOI":"10.3945\/jn.112.163824","article-title":"Dietary","volume":"142","author":"Shen","year":"2012","journal-title":"J. Nutr"},{"key":"2020081201563016300_CIT0036","doi-asserted-by":"crossref","first-page":"754","DOI":"10.3389\/fimmu.2018.00754","article-title":"Role of C-reactive protein at sites of inflammation and infection","volume":"9","author":"Sproston","year":"2018","journal-title":"Front. Immunol"},{"key":"2020081201563016300_CIT0037","doi-asserted-by":"crossref","first-page":"56","DOI":"10.1186\/s40104-019-0366-1","article-title":"Effect of mucin 4 allele on susceptibility to experimental infection with enterotoxigenic F4 Escherichia coli in pigs fed experimental diets","volume":"10","author":"Sterndale","year":"2019","journal-title":"J. Anim. Sci. Biotechnol"},{"key":"2020081201563016300_CIT0038","doi-asserted-by":"crossref","first-page":"4503","DOI":"10.1093\/jas\/skz303","article-title":"Technical Note: Novel delivery methods for an enterotoxigenic Escherichia coli infection model in MUC4-locus sequenced weaner pigs1","volume":"97","author":"Sterndale","year":"2019","journal-title":"J. Anim. Sci"},{"key":"2020081201563016300_CIT0039","doi-asserted-by":"crossref","first-page":"245","DOI":"10.1093\/clinchem\/40.2.245","article-title":"Plasma amino acids determined by liquid chromatography within 17 minutes","volume":"40","author":"Terrlink","year":"1994","journal-title":"Clin. Chem"},{"issue":"4","key":"2020081201563016300_CIT0040","article-title":"Acute phase proteins and their use in the diagnosis of diseases in ruminants: a review","volume":"59","author":"Tothova","year":"2014","journal-title":"Vet. Med. (Praha)"},{"issue":"1","key":"2020081201563016300_CIT0041","doi-asserted-by":"crossref","first-page":"148","DOI":"10.2527\/jas.2007-0732","article-title":"A tryptophan-enriched diet improves feed intake and growth performance of susceptible weanling pigs orally challenged with K88","volume":"87","author":"Trevisi","year":"2009","journal-title":"J. Anim. Sci"},{"key":"2020081201563016300_CIT0042","doi-asserted-by":"crossref","first-page":"151","DOI":"10.1016\/j.physbeh.2015.02.049","article-title":"Evidence for a link between tail biting and central monoamine metabolism in pigs (Sus scrofa domestica)","volume":"143","author":"Valros","year":"2015","journal-title":"Physiol. Behav"},{"issue":"5","key":"2020081201563016300_CIT0043","doi-asserted-by":"crossref","DOI":"10.4172\/2168-975X.1000137","article-title":"The brain-gut axis: from pathophysiology to possible future strategies of","volume":"3","author":"Vigneri","year":"2014","journal-title":"Brain Disord. Ther"},{"key":"2020081201563016300_CIT0044","doi-asserted-by":"crossref","first-page":"11","DOI":"10.3109\/00365517409104201","article-title":"Studies on tryptophan metabolism in man: the effect of hormones and vitamin B6 on urinary excretion of metabolites of the kynurenine pathway: part 1","volume":"33","author":"Wolf","year":"1974","journal-title":"Scan. J. Clin. Lab. Inv"}],"container-title":["Journal of Animal Science"],"original-title":[],"language":"en","link":[{"URL":"http:\/\/academic.oup.com\/jas\/advance-article-pdf\/doi\/10.1093\/jas\/skaa190\/33427472\/skaa190.pdf","content-type":"application\/pdf","content-version":"am","intended-application":"syndication"},{"URL":"http:\/\/academic.oup.com\/jas\/article-pdf\/98\/8\/skaa190\/33640242\/skaa190.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"http:\/\/academic.oup.com\/jas\/article-pdf\/98\/8\/skaa190\/33640242\/skaa190.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2020,8,12]],"date-time":"2020-08-12T19:40:22Z","timestamp":1597261222000},"score":1,"resource":{"primary":{"URL":"https:\/\/academic.oup.com\/jas\/article\/doi\/10.1093\/jas\/skaa190\/5862528"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,6,25]]},"references-count":44,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2020,6,25]]},"published-print":{"date-parts":[[2020,8,1]]}},"URL":"https:\/\/doi.org\/10.1093\/jas\/skaa190","relation":{},"ISSN":["0021-8812","1525-3163"],"issn-type":[{"value":"0021-8812","type":"print"},{"value":"1525-3163","type":"electronic"}],"subject":[],"published-other":{"date-parts":[[2020,8]]},"published":{"date-parts":[[2020,6,25]]},"article-number":"skaa190"}}