{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,2]],"date-time":"2026-10-02T14:36:40Z","timestamp":1790951800118,"version":"4.1.0"},"reference-count":54,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2022,5,17]],"date-time":"2022-05-17T00:00:00Z","timestamp":1652745600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100012166","name":"National Key Research and Development Program of China","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100012166","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100021171","name":"Basic and Applied Basic Research Foundation of Guangdong Province","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100021171","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Vet. Sci."],"abstract":"<jats:p>This study investigated the effect of a low protein (LP) diet on growth performance, nitrogen emission, carcass traits, meat quality, and gut microbiota in finishing pigs. Fifty-four barrows (Duroc \u00d7 Landrace \u00d7 Yorkshire) were randomly assigned to three treatments with six replicates (pens) of three pigs each. The pigs were fed with either high protein (HP, 16% CP), medium protein (MP, 12% CP), and LP diets (10% CP), respectively. The LP diets did not influence the growth performance, but significantly decreased the plasma urea nitrogen contents and fecal nitrogen emission (<jats:italic>P<\/jats:italic> &amp;lt; 0.05). The LP diet significantly decreased the plasma contents of malondialdehyde (MDA) and increased the plasma glutathione (GSH) contents (<jats:italic>P<\/jats:italic> &amp;lt; 0.05). The LP diets significantly increased the backfat thickness at the first and last ribs, L<jats:sup>*<\/jats:sup> (lightness) value of meat color, and muscle fiber density in the <jats:italic>longissimus dorsi<\/jats:italic> (<jats:italic>P<\/jats:italic> &amp;lt; 0.05). The messenger RNA (mRNA) expression of fatty acid synthetase (<jats:italic>FAS<\/jats:italic>), peroxisome proliferator-activated receptor-gamma (<jats:italic>PPAR<\/jats:italic>\u03b3), <jats:italic>leptin<\/jats:italic>, and acetyl-CoA carboxylase (<jats:italic>ACC<\/jats:italic>) was significantly downregulated, while that of carnitine palmitoyltransferase 1 (<jats:italic>CPT<\/jats:italic>1) and myosin heavy chain (<jats:italic>MYHC<\/jats:italic>) <jats:italic>IIx<\/jats:italic> in the <jats:italic>longissimus Dorsi muscle<\/jats:italic> was significantly upregulated by LP diets (<jats:italic>P<\/jats:italic> &amp;lt; 0.05). The 16S sequencing analysis showed that the abundance of unidentified Bacteria at the phylum level, and <jats:italic>Halanaerobium<\/jats:italic> and <jats:italic>Butyricicoccus<\/jats:italic>at at the genus level in the colonic digesta were significantly decreased by LP diet (<jats:italic>P<\/jats:italic> &amp;lt; 0.05). The LP diet significantly decreased the observed species of \u03b1-diversity in both ileal and colonic microbiota (<jats:italic>P<\/jats:italic> &amp;lt; 0.05). Spearman correlation analysis identified a significant positive correlation between the abundance of the ileal genera <jats:italic>Streptococcus<\/jats:italic> and L<jats:sup>*<\/jats:sup> value at 24 and 48 h, and a significant negative correlation between unidentified_<jats:italic>Ruminococcasceae<\/jats:italic> in both ileum and colon with L<jats:sup>*<\/jats:sup> value at 24 h (<jats:italic>P<\/jats:italic> &amp;lt; 0.05). Collectively, the LP diet supplemented with lysine, methionine, threonine, and tryptophan could reduce the fecal nitrogen emission without affecting growth performance and improve meat quality by regulating the antioxidant capacity and gene expression involved in fat metabolism as well as modulating the gut microbiota composition in finishing pigs.<\/jats:p>","DOI":"10.3389\/fvets.2022.843957","type":"journal-article","created":{"date-parts":[[2022,5,17]],"date-time":"2022-05-17T07:45:00Z","timestamp":1652773500000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":30,"title":["Low Protein Diet Improves Meat Quality and Modulates the Composition of Gut Microbiota in Finishing Pigs"],"prefix":"10.3389","volume":"9","author":[{"given":"Cui","family":"Zhu","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jingsen","family":"Yang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Qiwen","family":"Wu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jingping","family":"Chen","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xuefen","family":"Yang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Li","family":"Wang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zongyong","family":"Jiang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2022,5,17]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"60","DOI":"10.1186\/s40104-018-0276-7","article-title":"Advances in low-protein diets for swine","volume":"9","author":"Wang","year":"2018","journal-title":"J Anim Sci Biotechnol."},{"key":"B2","doi-asserted-by":"publisher","first-page":"43412","DOI":"10.1038\/srep43412","article-title":"Moderate dietary protein restriction alters the composition of gut microbiota and improves ileal barrier function in adult pig model","volume":"7","author":"Fan","year":"2017","journal-title":"Sci Rep."},{"key":"B3","doi-asserted-by":"publisher","first-page":"144","DOI":"10.1016\/j.livsci.2007.06.018","article-title":"Effects of low-protein diets supplemented with crystalline amino acids on performance and intestinal development in piglets over the first 2 weeks after weaning","volume":"115","author":"Yue","year":"2008","journal-title":"Livest Sci."},{"key":"B4","doi-asserted-by":"publisher","first-page":"2463","DOI":"10.1017\/S1751731119000776","article-title":"Protein restriction and succedent realimentation affecting ileal morphology, ileal microbial composition and metabolites in weaned piglets","volume":"13","author":"Shi","year":"2019","journal-title":"Animal."},{"key":"B5","doi-asserted-by":"publisher","first-page":"3075","DOI":"10.2527\/2003.81123075x","article-title":"Influence of dietary protein level, amino acid supplementation, and dietary energy levels on growing-finishing pig performance and carcass composition","volume":"81","author":"Kerr","year":"2003","journal-title":"J Anim Sci."},{"key":"B6","doi-asserted-by":"publisher","first-page":"7","DOI":"10.1016\/j.meatsci.2009.11.015","article-title":"Effect of protein level in commercial diets on pork meat quality","volume":"85","author":"Alonso","year":"2010","journal-title":"Meat Sci."},{"key":"B7","doi-asserted-by":"publisher","first-page":"123","DOI":"10.1016\/j.meatsci.2013.03.001","article-title":"Effects of low protein diets on pigs with a lean genotype. 1. 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