Our study explored the effect of dietary thiamin on growth and immunity (intestine, head kidney, spleen and liver) of young grass carp (Ctenopharyngodon idella). Fish were fed diets containing six graded levels of thiamin at 0.12-2.04 mg/kg diet for 8 weeks. The percentage weight gain (PWG), feed intake and feed efficiency were lower in fish fed the 0.12 mg/kg diet. Thiamin deficiency decreased complement 3 content, lysozyme (LA) and acid phosphatase activities, mRNA levels of hepcidin and interleukin (IL) 10, elevated mRNA levels of interferon gamma 2, tumor necrosis factor alpha, IL-10 and IL-8 in intestine, head kidney, spleen and liver. The mRNA levels of inhibitor protein-kappa B alpha, target of rapamycin (TOR) and NF-E2-related factor 2 (Nrf2), the activities and mRNA levels of copper/zinc superoxide dismutase, manganese superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase and glutathione reductase were down-regulated, mRNA levels of myosin light-chain kinase (MLCK), I kappa B kinases (IKK beta and IKK gamma), nuclear factor kappa B P65 (NF-kappa B P65) and Kelch-like-ECH-associated protein la (Keap1a) were up-regulated in the intestine of fish fed the thiamin-deficient diet. Additionally, thiamin deficiency decreased claudin b, c and 3, ZO-1 and occludin mRNA levels in each intestinal segment, increased claudin 12 and claudin 15a mRNA levels in distal intestine. In conclusion, thiamin deficiency decreased fish growth and immunity of intestine, head kidney, spleen and liver. The dietary thiamin requirement of young grass carp (242-742 g) based on intestinal LA activity or PWG were determined to be 1.15 or 0.90 mg/kg diet, respectively. (C) 2015 Elsevier Ltd. All rights reserved.
National Basic Research Program of China (973 Program)(2014CB138600)
; National Department Public Benefit Research Foundation (Agriculture) of China(201003020)
; Specialized Research Fund for the Doctoral Program of Higher Education of China(20135103110001)
; Science and Technology Support Program of Sichuan Province of China(2014NZ0003)
; Major Scientific and Technological Achievement Transformation Project of Sichuan Province of China(2012NC0007
; Demonstration of Major Scientific and Technological Achievement Transformation Project of Sichuan Province of China(2015CC0011)
; Natural Science Foundation for Young Scientists of Sichuan Province(2014JQ0007)
; Sichuan Province Research Foundation for Basic Research(2013JY0082)
; 2013NC0045)
