title: Effect of dietary phosphorus deficiency on the growth, immune function and structural integrity of head kidney, spleen and skin in young grass carp (Ctenopharyngodon idella).
abstract: This study evaluates the effects of dietary phosphorus on the growth, immune function and structural integrity (head kidney, spleen and skin) of young grass carp (Ctenopharyngodon idella) that were fed graded levels of available phosphorus (0.95-8.75 g/kg diet). Results indicated that phosphorus deficiency decreased the growth performance of young grass carp. In addition, the results first demonstrated that compared with the optimal phosphorus level, phosphorus deficiency depressed the lysozyme (LZ) and acid phosphatase (ACP) activities and the complement 3 (C3), C4 and immunoglobulin M (IgM) contents, and down-regulated the mRNA levels of antimicrobial peptides, anti-inflammatory cytokines, inhibitor of κBα (IκBα) and target of rapamycin (TOR), whereas it up-regulated pro-inflammatory cytokines, nuclear factor kappa B (NF-κB) p65 and NF-κB p52 mRNA levels to decrease fish head kidney and spleen immune functions. Moreover, phosphorus deficiency up-regulated the mRNA levels of Kelch-like-ECH-associated protein 1a (Keap1a), Fas ligand (FasL), apoptotic protease activating factor-1 (Apaf-1), Bcl-2 associated X protein (Bax), caspase -2, -3, -7, -8 and -9, p38 mitogen-activated protein kinase (MAPK) and myosin light chain kinase (MLCK), whereas it depressed the glutathione (GSH) contents and antioxidant enzymes activities, and down-regulated the mRNA levels of antioxidant enzymes, NF-E2-related factor 2 (Nrf2), B-cell lymphoma protein-2 (Bcl-2), myeloid cell leukemia-1 (Mcl-1) and tight junction complexes to attenuate fish head kidney and spleen structural integrity. In addition, phosphorus deficiency increased skin hemorrhage and lesions morbidity. Finally, based on the percent weight gain (PWG) and the ability to combat skin hemorrhage and lesions, the dietary available phosphorus requirements for young grass carp (254.56-898.23 g) were estimated to be 4.10 and 4.13 g/kg diet, respectively. In summary, phosphorus deficiency decreases the growth performance, and impairs immune function and structural integrity in the head kidney, spleen and skin of young grass carp.
authors.affiliation: Animal Nutrition Institute, Sichuan Agricultural University, Sichuan, Chengdu 611130, China.
authors.forename: Kang
authors.initials: K
authors.lastname: Chen
authors.affiliation: Animal Nutrition Institute, Sichuan Agricultural University, Sichuan, Chengdu 611130, China; Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Sichuan, Chengdu 611130, China; Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Sichuan, Chengdu 611130, China.
authors.forename: Wei-Dan
authors.initials: WD
authors.lastname: Jiang
authors.affiliation: Animal Nutrition Institute, Sichuan Agricultural University, Sichuan, Chengdu 611130, China; Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Sichuan, Chengdu 611130, China; Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Sichuan, Chengdu 611130, China.
authors.forename: Pei
authors.initials: P
authors.lastname: Wu
authors.affiliation: Animal Nutrition Institute, Sichuan Agricultural University, Sichuan, Chengdu 611130, China; Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Sichuan, Chengdu 611130, China; Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Sichuan, Chengdu 611130, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Animal Nutrition Institute, Sichuan Academy of Animal Science, Chengdu 610066, China.
authors.forename: Sheng-Yao
authors.initials: SY
authors.lastname: Kuang
authors.affiliation: Animal Nutrition Institute, Sichuan Academy of Animal Science, Chengdu 610066, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Tang
authors.affiliation: Animal Nutrition Institute, Sichuan Academy of Animal Science, Chengdu 610066, China.
authors.forename: Wu-Neng
authors.initials: WN
authors.lastname: Tang
authors.affiliation: Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
authors.forename: Yong-An
authors.initials: YA
authors.lastname: Zhang
authors.affiliation: Animal Nutrition Institute, Sichuan Agricultural University, Sichuan, Chengdu 611130, China; Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Sichuan, Chengdu 611130, China; Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Sichuan, Chengdu 611130, China. Electronic address: xqzhouqq@tom.com.
authors.forename: Xiao-Qiu
authors.initials: XQ
authors.lastname: Zhou
authors.affiliation: Animal Nutrition Institute, Sichuan Agricultural University, Sichuan, Chengdu 611130, China; Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Sichuan, Chengdu 611130, China; Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Sichuan, Chengdu 611130, China. Electronic address: fenglin@sicau.edu.cn.
authors.forename: Lin
authors.initials: L
authors.lastname: Feng
mesh_terms: D016980:Aeromonas hydrophila / Q000502:physiology; D000821:Animal Feed / Q000032:analysis; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D017209:Apoptosis / Q000502:physiology; D002347:Carps / Q000254:growth & development / Q000276:immunology; D004032:Diet / Q000662:veterinary*; D019587:Dietary Supplements / Q000032:analysis; D005393:Fish Diseases / Q000276:immunology* / Q000382:microbiology; D029941:Fish Proteins / Q000235:genetics / Q000378:metabolism; D016905:Gram-Negative Bacterial Infections / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D060226:Head Kidney / Q000378:metabolism; D007113:Immunity, Innate / Q000502:physiology*; D010758:Phosphorus / Q000172:deficiency*; D016226:Phosphorus, Dietary / Q000276:immunology* / Q000378:metabolism; D012867:Skin / Q000378:metabolism; D013154:Spleen / Q000378:metabolism; D019108:Tight Junctions / Q000502:physiology
chemical_list: D000975:Antioxidants; D029941:Fish Proteins; D016226:Phosphorus, Dietary; D010758:Phosphorus
keywords: Grass carp (Ctenopharyngodon idella); Head kidney; Immune function; Phosphorus deficiency; Spleen; Structural integrity