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. 2018 May;76:333-346. doi: 10.1016/j.fsi.2018.03.017. Epub 2018 Mar 12.
In this study, we investigated the effects of dietary myo-inositol on the intestinal immune barrier function and related signaling pathway in young grass carp (Ctenopharyngodon idella). A total of 540 young grass carp (221.33 ± 0.84 g) were fed six diets containing graded levels of myo-inositol (27.0, 137.9, 286.8, 438.6, 587.7 and 737.3 mg/kg) for 10 weeks. After the growth trial, fish were challenged with Aeromonas hydrophila. The results indicated that compared with the optimal dietary myo-inositol level, myo-inositol deficiency (27.0 mg/kg diet): (1) decreased lysozyme (LZ) and acid phosphatase (ACP) activities, as well as complement 3 (C3), C4 and immunoglobulin M (IgM) contents in the proximal intestine (PI), middle intestine (MI) and distal intestine (DI) of young grass carp (P < 0.05). (2) down-regulated the mRNA levels of anti-microbial substance: liver expressed antimicrobial peptide (LEAP) 2A, LEAP-2B, hepcidin, β-defensin-1 and mucin2 in the PI, MI and DI of young grass carp (P < 0.05). (3) up-regulated pro-inflammatory cytokines [IL-1β (not in DI), TNF-α and IL-8], nuclear factor kappa B P65 (not NF-κB P52), c-Rel, IκB kinaseα (IKKα), IKKβ and IKKγ mRNA levels in the PI, MI and DI of young grass carp (P < 0.05); and down-regulated pro-inflammatory cytokines IL-15 (not in DI) and inhibitor of κBα (IκBα) mRNA levels (P < 0.05). (4) down-regulated the mRNA levels of anti-inflammatory cytokines [IL-10 (not in DI), IL-11, IL-4/13B (not IL-4/13A), TGF-β1 and TGF-β2], target of rapamycin (TOR), eIF4E-binding proteins 1 (4E-BP1) and ribosomal protein S6 kinase 1 (S6k1) in the PI, MI and DI of young grass carp (P < 0.05). All data indicated that myo-inositol deficiency could decrease fish intestine immunity and cause inflammation under infection of A. hydrophila. Finally, the optimal dietary myo-inositol levels for the ACP and LZ activities in the DI were estimated to be 415.1 and 296.9 mg/kg diet, respectively.
在这项研究中，我们研究了肌醇对草鱼幼鱼肠道免疫屏障功能和相关信号通路的影响。将 540 条草鱼（221.33±0.84g）分别投喂六组含有不同梯度肌醇水平（27.0、137.9、286.8、438.6、587.7 和 737.3mg/kg）的饲料，持续 10 周。生长试验结束后，用嗜水气单胞菌对鱼进行攻毒。结果表明，与最佳饲粮肌醇水平相比，肌醇缺乏（27.0mg/kg 饲粮）：（1）降低了草鱼近端肠（PI）、中肠（MI）和远端肠（DI）的溶菌酶（LZ）和酸性磷酸酶（ACP）活性，以及补体 3（C3）、C4 和免疫球蛋白 M（IgM）含量（P<0.05）。（2）下调了 PI、MI 和 DI 中抗微生物物质：肝表达抗菌肽（LEAP）2A、LEAP-2B、hepcidin、β-防御素-1 和粘蛋白 2 的 mRNA 水平（P<0.05）。（3）上调了促炎细胞因子[白细胞介素-1β（不在 DI 中）、肿瘤坏死因子-α 和白细胞介素-8]、核因子 kappa B P65（不在 NF-κB P52 中）、c-Rel、IKKα、IKKβ和 IKKγ的 mRNA 水平在 PI、MI 和 DI 中的草鱼（P<0.05）；并下调了促炎细胞因子白细胞介素-15（不在 DI 中）和κB 抑制物α（IκBα）的 mRNA 水平（P<0.05）。（4）下调了抗炎细胞因子[白细胞介素-10（不在 DI 中）、白细胞介素-11、白细胞介素-4/13B（不在白细胞介素-4/13A 中）、转化生长因子-β1 和转化生长因子-β2]、雷帕霉素靶蛋白（TOR）、真核起始因子 4E 结合蛋白 1（4E-BP1）和核糖体蛋白 S6 激酶 1（S6k1）的 mRNA 水平在 PI、MI 和 DI 中的草鱼（P<0.05）。所有数据表明，肌醇缺乏可降低鱼体肠道免疫力，并在感染嗜水气单胞菌后引起炎症。最后，估计 DI 中 ACP 和 LZ 活性的最佳饲粮肌醇水平分别为 415.1 和 296.9mg/kg 饲料。
