Li Shun-Quan, Feng Lin, Jiang Wei-Dan, Liu Yang, Jiang Jun, Wu Pei, Kuang Sheng-Yao, Tang Ling, Tang Wu-Neng, Zhang Yong-An, Zhou Xiao-Qiu
Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130, China.
Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130, China; Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130, China; Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Chengdu, 611130, China.
Fish Shellfish Immunol. 2016 Aug;55:212-22. doi: 10.1016/j.fsi.2016.05.005. Epub 2016 May 13.
To investigate the effects of dietary niacin on gill immunity, tight junction proteins, antioxidant system and related signaling molecules mRNA expression, young grass carp (Ctenopharyngodon idella) were fed six diets containing graded levels of niacin (3.95-55.01 mg/kg diet) for 8 weeks. The study indicated that niacin deficiency decreased lysozyme and acid phosphatase activities, and complement 3 content, and caused oxidative damage that might be partly due to the decreased copper, zinc superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase and glutathione-S-transferase activities and reduced glutathione content in fish gills (P < 0.05). Moreover, the relative mRNA levels of antimicrobial peptides (liver expressed antimicrobial peptide 2 and Hepcidin), anti-inflammatory cytokines (interleukin 10 and transforming growth factor β1), tight junction proteins (Occludin, zonula occludens 1, Claudin-15 and -3), signaling molecules (inhibitor of κBα (IκBα), target of rapamycin (TOR), ribosomal protein S6 kinase 1 (S6K1) and NF-E2-related factor 2 (Nrf2)) and antioxidant enzymes were significantly decreased (P < 0.05) in niacin-deficient diet group. Conversely, the mRNA levels of pro-inflammatory cytokines (tumor necrosis factor α, interleukin 8, interferon γ2, and interleukin 1β), signaling molecules (nuclear factor kappa B p65, IκB kinase α, IκB kinase β, IκB kinase γ, Kelch-like-ECH-associated protein 1b, myosin light chain kinase and p38 mitogen-activated protein kinase (p38 MAPK) were significantly increased (P < 0.05) in fish gills fed niacin-deficient diet. Interestingly, the varying niacin levels of 3.95-55.01 mg/kg diet had no effect on the mRNA level of Kelch-like-ECH-associated protein 1a, Claudin-c and -12 in fish gills (P > 0.05). In conclusion, niacin deficiency decreased gill immunity, impaired gill antioxidant system, as well as regulated mRNA expression of gill tight junction proteins and related signaling molecules of fish.
为研究饲料中烟酸对草鱼鳃免疫、紧密连接蛋白、抗氧化系统及相关信号分子mRNA表达的影响，将幼草鱼（Ctenopharyngodon idella）投喂含不同梯度烟酸水平（3.95 - 55.01 mg/kg饲料）的六种饲料，为期8周。研究表明，烟酸缺乏会降低溶菌酶和酸性磷酸酶活性以及补体3含量，并导致氧化损伤，这可能部分归因于鱼鳃中铜、锌超氧化物歧化酶、过氧化氢酶、谷胱甘肽还原酶、谷胱甘肽过氧化物酶和谷胱甘肽-S-转移酶活性降低以及谷胱甘肽含量减少（P < 0.05）。此外，在烟酸缺乏饲料组中，抗菌肽（肝脏表达抗菌肽2和铁调素）、抗炎细胞因子（白细胞介素10和转化生长因子β1）、紧密连接蛋白（闭合蛋白、闭锁小带蛋白1、Claudin-15和-3）、信号分子（κBα抑制蛋白（IκBα）、雷帕霉素靶蛋白（TOR）、核糖体蛋白S6激酶1（S6K1）和核因子E2相关因子2（Nrf2））以及抗氧化酶的相对mRNA水平显著降低（P < 0.05）。相反，在投喂烟酸缺乏饲料的草鱼鳃中，促炎细胞因子（肿瘤坏死因子α、白细胞介素8、干扰素γ2和白细胞介素1β）、信号分子（核因子κB p65、IκB激酶α、IκB激酶β、IκB激酶γ、类ECH相关蛋白1b、肌球蛋白轻链激酶和p38丝裂原活化蛋白激酶（p38 MAPK））的mRNA水平显著升高（P < 0.05）。有趣的是，饲料中3.95 - 55.01 mg/kg的不同烟酸水平对草鱼鳃中类ECH相关蛋白1a、Claudin-c和-12的mRNA水平没有影响（P > 0.05）。总之，烟酸缺乏会降低草鱼鳃的免疫力，损害鳃抗氧化系统，并调节鳃紧密连接蛋白和相关信号分子的mRNA表达。
