{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T09:58:50Z","timestamp":1785405530204,"version":"3.56.0"},"reference-count":40,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2026,7,14]],"date-time":"2026-07-14T00:00:00Z","timestamp":1783987200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"earmarked fund for CARS","award":["CARS-46"],"award-info":[{"award-number":["CARS-46"]}]},{"award":["CARS-46"],"award-info":[{"award-number":["CARS-46"]}],"id":[{"id":"https:\/\/ror.org\/03p5eky76","id-type":"ROR","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004608","name":"Natural Science Foundation of Jiangsu Province","doi-asserted-by":"crossref","award":["BK20240324"],"award-info":[{"award-number":["BK20240324"]}],"id":[{"id":"10.13039\/501100004608","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Veterinary Sciences"],"abstract":"<jats:p>An 8-week trial evaluated dietary copper methionine (CM) on body and flesh color in yellowed channel catfish. Basic diets were supplemented with CM at 0 (control, Cu1), 7 (Cu2), 14 (Cu3), 21 (Cu4), and 27 (Cu5) mg\/kg, with corresponding measured copper levels of 10.82, 12.63, 14.35, 15.58, and 17.40 mg\/kg. In skin, GSH levels in Cu2-Cu5 groups and GSH-Px activities in Cu2-Cu4 groups were increased, and in muscle, CAT activities in Cu3-Cu5 groups and GSH levels in Cu4-Cu5 groups were increased. Gene expression analysis showed downregulated keap1 (Cu2\u2013Cu4 in skin; Cu3\u2013Cu5 in muscle) and nf\u03bab (Cu2\u2013Cu5 in skin), upregulated nrf2 (Cu3\u2013Cu5 in skin; Cu4 in muscle) and il-10 (Cu4 in skin). Colorimetric analysis showed reduced the values of b* in skin (Cu3\u2013Cu5) and muscle (Cu2\u2013Cu5). Uranidin content decreased in skin (Cu3\u2013Cu5) and muscle (Cu4\u2013Cu5), while melanin and tyrosinase increased in skin (melanin: Cu2\u2013Cu3; tyrosinase: Cu3\u2013Cu4) and muscle (Cu3\u2013Cu5). The expression of melanogenesis-related genes (mitf, tyr, etb, camk2, slc24a5) was increased in skin and muscle of Cu3-Cu5 groups, while the uranidin synthesis gene xdh was downregulated. Overall, optimal effects were observed at 14\u201321 mg\/kg CM (measured copper: 14.35\u201315.58 mg\/kg).<\/jats:p>","DOI":"10.3390\/vetsci13070683","type":"journal-article","created":{"date-parts":[[2026,7,15]],"date-time":"2026-07-15T03:06:52Z","timestamp":1784084812000},"page":"683","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["A Study on the Effect of Copper Methionine in Alleviating Yellowing in Channel Catfish"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0009-0007-2405-4221","authenticated-orcid":false,"given":"Dongyu","family":"Huang","sequence":"first","affiliation":[{"name":"Key Laboratory of Integrated Rice-Fish Farming Ecology, Ministry of Agriculture and Rural Affairs, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lu","family":"Zhang","sequence":"additional","affiliation":[{"name":"Tongwei Agricultural Development Co., Ltd., Key Laboratory of Aquatic Nutrition and Smart Farming, Ministry of Agriculture and Rural Affairs, Aquatic Health and Intelligent Aquaculture Key Laboratory of Sichuan Province, Chengdu 610093, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chunyu","family":"Xue","sequence":"additional","affiliation":[{"name":"Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-2649-4707","authenticated-orcid":false,"given":"Leimin","family":"Zhang","sequence":"additional","affiliation":[{"name":"Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mingchun","family":"Ren","sequence":"additional","affiliation":[{"name":"Key Laboratory of Integrated Rice-Fish Farming Ecology, Ministry of Agriculture and Rural Affairs, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, China"},{"name":"Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiaodi","family":"Xu","sequence":"additional","affiliation":[{"name":"Key Laboratory of Integrated Rice-Fish Farming Ecology, Ministry of Agriculture and Rural Affairs, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6502-3914","authenticated-orcid":false,"given":"Hualiang","family":"Liang","sequence":"additional","affiliation":[{"name":"Key Laboratory of Integrated Rice-Fish Farming Ecology, Ministry of Agriculture and Rural Affairs, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, China"},{"name":"Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Haifeng","family":"Mi","sequence":"additional","affiliation":[{"name":"Tongwei Agricultural Development Co., Ltd., Key Laboratory of Aquatic Nutrition and Smart Farming, Ministry of Agriculture and Rural Affairs, Aquatic Health and Intelligent Aquaculture Key Laboratory of Sichuan Province, Chengdu 610093, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"185","DOI":"10.1016\/S0044-8486(96)01503-7","article-title":"Trace minerals in fish nutrition","volume":"151","author":"Watanabe","year":"1997","journal-title":"Aquaculture"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1515\/ntrev-2017-0159","article-title":"Copper nanoparticles as an alternative feed additive in poultry diet: A review","volume":"7","author":"Scott","year":"2018","journal-title":"Nanotechnol. 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