title: Growth, digestive and absorptive capacity and antioxidant status in intestine and hepatopancreas of sub-adult grass carp Ctenopharyngodonidella fed graded levels of dietary threonine.
abstract: BACKGROUND
  This study was carried out to investigate effects of threonine levels on growth, digestive and absorptive capacity and antioxidant status in intestine and hepatopancreas of sub-adult grass carp (Ctenopharyngodonidella).
  
  
  RESULTS
  Weight gain, specific growth rate, feed intake and feed efficiency were significantly improved by dietary threonine (P < 0.05). Intestinal activities of trypsin, chymotrypsin, alpha-amylase, lipase, alkaline phosphatase, γ-glutamyl transpeptidase and creatine kinase took the similar trends. Contents of malondialdehyde and protein carbonyl in intestine and hepatopancreas were significantly decreased by dietary optimal threonine supplementation (P < 0.05). Anti-superoxide anion capacity, anti-hydroxyl radical capacity, glutathione content and activities of superoxide dismutase, catalase and glutathione-S-transferase in intestine and hepatopancreas were enhanced by dietary threonine (P < 0.05).
  
  
  CONCLUSIONS
  Dietary threonine could improve growth, enhance digestive and absorptive capacity and antioxidant status in intestine and hepatopancreas of sub-adult grass carp. The dietary threonine requirement of sub-adult grass carp (441.9-1,013.4 g) based on weight gain was 11.6 g/kg diet or 41.5 g/kg of dietary protein by quadratic regression analysis.
authors.affiliation: Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130 Sichuan China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Hong
authors.affiliation: Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130 Sichuan China ; Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130 Sichuan China ; Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Chengdu, 611130 Sichuan China.
authors.forename: Weidan
authors.initials: W
authors.lastname: Jiang
authors.affiliation: Sichuan Academy of Animal Science, Animal Nutrition Institute, Chengdu, 610066 China.
authors.forename: Shengyao
authors.initials: S
authors.lastname: Kuang
authors.affiliation: Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130 Sichuan China ; Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130 Sichuan China ; Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Chengdu, 611130 Sichuan China.
authors.forename: Kai
authors.initials: K
authors.lastname: Hu
authors.affiliation: Sichuan Academy of Animal Science, Animal Nutrition Institute, Chengdu, 610066 China.
authors.forename: Ling
authors.initials: L
authors.lastname: Tang
authors.affiliation: Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130 Sichuan China ; Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130 Sichuan China ; Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Chengdu, 611130 Sichuan China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130 Sichuan China ; Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130 Sichuan China ; Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Chengdu, 611130 Sichuan China.
authors.forename: Jun
authors.initials: J
authors.lastname: Jiang
authors.affiliation: Chinese Academy of Sciences, Institute of Hydrobiology, Wuhan, 430072 China.
authors.forename: Yongan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130 Sichuan China ; Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130 Sichuan China ; Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Chengdu, 611130 Sichuan China.
authors.forename: Xiaoqiu
authors.initials: X
authors.lastname: Zhou
authors.affiliation: Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130 Sichuan China ; Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130 Sichuan China ; Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Chengdu, 611130 Sichuan China.
authors.forename: Lin
authors.initials: L
authors.lastname: Feng
keywords: Antioxidant status; Grass carp; Intestinal enzyme activity; Threonine