Dietary myo-inositol deficiency decreased the growth performances and impaired intestinal physical barrier function partly relating to nrf2, jnk, e2f4 and mlck signaling in young grass carp (Ctenopharyngodon idella)

• Published in: Fish & Shellfish Immunology
• Main Authors: Li, Shuang-An, Jiang, Wei-Dan, Feng, Lin, Liu, Yang, Wu, Pei, Jiang, Jun, Kuang, Sheng-Yao, Tang, Ling, Tang, Wu-Neng, Zhang, Yong-An, Tang, Xu, Shi, He-Qun, Zhou, Xiao-Qiu
• Format: Report
• Language: English
• Published: ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD 2017
• Subjects: Myo-inositol; Grass carp (Ctenopharyngodon idella); Intestine; Antioxidant; Apoptosis; Proliferation; Tight junction; Fisheries; Immunology; Marine & Freshwater Biology; Veterinary Sciences; NF-KAPPA-B; MESSENGER-RNA EXPRESSION; TIGHT JUNCTION PROTEINS; ANTIOXIDANT ENZYME-ACTIVITIES; SALMON SALMO-SALAR; AEROMONAS-HYDROPHILA; IMMUNE-RESPONSE; OXIDATIVE STRESS; ATLANTIC SALMON; ACID DEFICIENCY; Atlantic salmon; Salmo salar
• Online Access: http://ir.ihb.ac.cn/handle/342005/31372; https://doi.org/10.1016/j.fsi.2017.06.032

In this study, we investigated the effects of dietary myo-inositol on the growth and intestinal physical barrier functions of young grass carp (Ctenopharyngodon idella). A total of 540 young grass carp (221.83 +/- 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 for 14 days. The results indicated that compared with optimal myo-inositol levels, myo-inositol deficiency (27.0 mg/kg diet): (1) decreased glutathione (GSH) contents and antioxidant enzymes activities, and down-regulated the mRNA levels of antioxidant enzymes [not glutathione-S-transferase (gst) pl and gstp2] and NF-E2-related factor 2 (nrf2), whereas up-regulated the reactive oxygen species (ROS), malondialdehyde (MDA) and protein carbonyl (PC) contents, and the mRNA levels of Kelchlike-ECH-associated protein 1 (keap1) in three intestinal segments of young grass carp (P < 0.05). (2) Up-regulated cysteinyl aspartic acid-protease (caspase)-2, -3, -7, -8, -9, apoptotic protease activating factor-1 (apaf-1), Bcl2-associated X protein (bax), fas ligand (fasl), gen-activated protein kinase (p38mapk) and c-Jun N-terminal protein kinase (ink) mRNA levels, whereas down-regulated B-cell lymphoma-2 (bcl-2), inhibitor of apoptosis proteins (iap) and myeloid cell leukemia-1 (mcl-1) mRNA levels in three intestinal segments of young grass carp (P < 0.05). (3) Down-regulated mRNA levels of cell cycle proteins cyclin b, cyclin d, cyclin e and E2F transcription factor 4 (e2f4) in three intestinal segments of young grass carp (P < 0.05). (4) Down-regulated the mRNA levels of zonula occludens (zo) 1, zo-2, occludin, claudin-b, -c, -f, -3c, -7a, -7b as well as -11, and up-regulated the mRNA levels of claudin-12, -15a (not -15b) and myosin light chain kinase (mlck) in three intestinal segments of young grass carp (P < 0.05). All above data indicated that dietary myo-inositol deficiency could damage physical barrier function in three intestinal segments of fish. Finally, the myo-inositol requirements based on the percent weight gain (PWG), reactive oxygen species (ROS) contents in the proximal intestine (PI), relative mRNA levels of caspase-2 (PI), cyclin b (MI) as well as claudin-b (PI) were estimated to be 276.7, 304.1, 327.9, 416.7 and 313.2 mg/kg diet, respectively. (C) 2017 Elsevier Ltd. All rights reserved.