title: Effect of dietary leucine on the growth parameters and expression of antioxidant, immune, and inflammatory genes in the head kidney of Labeo rohita fingerlings.
abstract: The present investigation evaluated the effects of dietary leucine (Leu) on growth performance, head kidney antioxidant status, and gene expression in Labeo rohita juveniles. Fish were fed with six isonitrogenous diets containing graded levels of Leu at 0.75 (control), 1.7, 3.2, 4.6, 6.3, and 7.6 g Leu kg(-1) of feed for 8 weeks. Compared with the control group, appropriate Leu supplementation significantly enhanced the percent weight gain (PWG), feed intake (FI), and protein efficiency ratio (PER) (P<0.05) but decreased the plasma ammonia content (PAC) (P<0.05). Similarly, optimal Leu supplementation stimulated head kidney glutathione (GSH) content, and superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities as compared to the control group; however, a reverse trend was observed in malondialdehyde (MDA) content. Further, relative gene-expression levels of lysozyme, complement C3, β-microglobulin, immunoglobulin-M, SOD, GPx, nuclear factor erythroid 2-related factor 2 (Nrf2), natural killer-cell enhancing factor β (NKEF-β), and toll-like receptor-22 (TLR22) in the head kidney were enhanced (P<0.05) at leucine levels of 4.6 g kg(-1) of feed. Conversely, the mRNA levels of tumour necrosis factor-α (TNF-α), Kelch-like-ECH-associated protein 1 (Keap1), and interleukin 1β (IL-1β) in head kidney were down-regulated by Leu supplementation. Collectively, our results revealed that appropriate Leu supplementation improved fish growth and antioxidant capacity, and regulated the mRNA levels of related signalling molecules in L. rohita juveniles. Based on the quadratic regression analysis of PWG, PER, and PAC, the optimum dietary leucine requirements of L. rohita juveniles were estimated to be 4.7, 4.5, and 4.8 g kg(-1) of feed.
authors.affiliation: Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Gwanak-ro, Seoul 151742, South Korea. Electronic address: giribiotek@gmail.com.
authors.forename: Sib Sankar
authors.initials: SS
authors.lastname: Giri
authors.affiliation: School of Life Sciences, Jawaharlal Nehru University, New Delhi, India. Electronic address: shibsankar.iicb@gmail.com.
authors.forename: Shib Sankar
authors.initials: SS
authors.lastname: Sen
authors.affiliation: Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Gwanak-ro, Seoul 151742, South Korea. Electronic address: chicheng0421@126.com.
authors.forename: Cheng
authors.initials: C
authors.lastname: Chi
authors.affiliation: Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Gwanak-ro, Seoul 151742, South Korea. Electronic address: hjoong1@nate.com.
authors.forename: Hyoun Joong
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Gwanak-ro, Seoul 151742, South Korea. Electronic address: arseidon@naver.com.
authors.forename: Saekil
authors.initials: S
authors.lastname: Yun
authors.affiliation: Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Gwanak-ro, Seoul 151742, South Korea. Electronic address: parksec@snu.ac.kr.
authors.forename: Se Chang
authors.initials: SC
authors.lastname: Park
authors.affiliation: Department of Biotechnology, Periyar Maniammai University, Thanjavur 613403, Tamil Nadu, India. Electronic address: drvsukumar@gmail.com.
authors.forename: V
authors.initials: V
authors.lastname: Sukumaran
mesh_terms: D000641:Ammonia / Q000097:blood; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D003530:Cyprinidae / Q000254:growth & development / Q000276:immunology* / Q000378:metabolism*; D019587:Dietary Supplements; D004435:Eating / Q000187:drug effects; D029941:Fish Proteins / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D005979:Glutathione Peroxidase / Q000235:genetics / Q000378:metabolism; D060226:Head Kidney / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism*; D018836:Inflammation Mediators / Q000378:metabolism; D007930:Leucine / Q000008:administration & dosage*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D015430:Weight Gain / Q000187:drug effects
chemical_list: D000975:Antioxidants; D029941:Fish Proteins; D018836:Inflammation Mediators; D012333:RNA, Messenger; D000641:Ammonia; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D007930:Leucine
keywords: Antioxidant gene; Head kidney; Immunity; Inflammatory gene; Labeo rohita; Leucine