{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,24]],"date-time":"2026-09-24T09:05:33Z","timestamp":1790240733109,"version":"4.1.0"},"reference-count":47,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2026,9,24]],"date-time":"2026-09-24T00:00:00Z","timestamp":1790208000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Performance Incentive and Guidance Special Project for Scientific Research Institutions of Chongqing","award":["CSTB2023JXJL-YFX0012"],"award-info":[{"award-number":["CSTB2023JXJL-YFX0012"]}]},{"name":"Chongqing Financial Fund Project","award":["24514C"],"award-info":[{"award-number":["24514C"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Animals"],"abstract":"<jats:p>This study aimed to investigate the effects of supplementing rumen-protected glycine and methionine to low-protein diets on the growth and development of Yudong black goats. Sixty 4-month-old Yudong black goats with comparable body weights (21.0 \u00b1 0.74 kg) were randomly assigned to four groups: the control (CON), rumen-protected glycine (GLY), rumen-protected methionine (MET), and mixed-amino-acid (MAG) groups. The CON group was fed a basal diet containing 13.4% crude protein, whereas the GLY, MET and MAG groups received diets with 11.0% crude protein supplemented with 4 g\/kg rumen-protected glycine, 4 g\/kg rumen-protected methionine, and 2 g\/kg rumen-protected glycine + 2 g\/kg rumen-protected methionine, respectively. The experimental period lasted 60 days. Compared with the CON group, supplementation with glycine or methionine alone did not affect the growth performance of goats (p &gt; 0.05). However, the MAG group exhibited significantly increased longissimus muscle area and C20:3n6 content, together with a significant reduction in ALB (p &lt; 0.05). In addition, the relative abundance of Prevotella was significantly higher in the MET group than in the CON group (p &lt; 0.05), and strong correlations existed between dominant ruminal bacterial genera and indicators of growth and slaughter performance. In conclusion, supplementation with rumen-protected amino acids in low-protein diets can markedly improve slaughter performance and meat quality of Yudong black goats without impairing their growth or normal physiological metabolism.<\/jats:p>","DOI":"10.3390\/ani16193002","type":"journal-article","created":{"date-parts":[[2026,9,24]],"date-time":"2026-09-24T08:06:37Z","timestamp":1790237197000},"page":"3002","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Effects of Rumen-Protected Glycine and Methionine Supplementation in a Low-Protein Diet on Growth and Development, Slaughter Performance, Meat Quality, and Rumen Microflora of Yudong Black Goats"],"prefix":"10.3390","volume":"16","author":[{"given":"Caiye","family":"Zhu","sequence":"first","affiliation":[{"name":"Collage of Animal Science and Technology, Gansu Agricultural University, Lanzhou 730070, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"data-curation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"}]},{"given":"Yu","family":"Qing","sequence":"additional","affiliation":[{"name":"Collage of Animal Science and Technology, Gansu Agricultural University, Lanzhou 730070, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"}]},{"given":"Yue","family":"Zhang","sequence":"additional","affiliation":[{"name":"Collage of Animal Science and Technology, Gansu Agricultural University, Lanzhou 730070, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"}]},{"given":"Xiaoyan","family":"Sun","sequence":"additional","affiliation":[{"name":"Chongqing Academy of Animal Sciences, Chongqing 402460, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"resources","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"}]},{"given":"Hangxing","family":"Ren","sequence":"additional","affiliation":[{"name":"Chongqing Academy of Animal Sciences, Chongqing 402460, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"resources","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"}]},{"given":"Youxiang","family":"Zeng","sequence":"additional","affiliation":[{"name":"Wulong District Livestock Industry Development Center, Chongqing 408000, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"resources","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"}]},{"given":"Xiaoyu","family":"Huang","sequence":"additional","affiliation":[{"name":"Collage of Animal Science and Technology, Gansu Agricultural University, Lanzhou 730070, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"131611","DOI":"10.1016\/j.foodchem.2021.131611","article-title":"Effects of different feeding regimes on muscle metabolism and its association with meat quality of Tibetan sheep","volume":"374","author":"Zhang","year":"2022","journal-title":"Food Chem."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1","DOI":"10.4141\/CJAS10034","article-title":"Review: Ammonia emissions from dairy farms and beef feedlots","volume":"91","author":"Hristov","year":"2011","journal-title":"Can. 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