| 论文摘要： |
A 106-day growth trial was executed in a flow-through system to investigate the effects of dietary vitamin A on growth, hematological indices, digestive functions, body composition and lipid metabolism of on-growing gibel carp (69.39 +/- 0.08 g). Fish were randomly assigned to seven groups and fed with different diets containing 273, 1278, 1962, 3155, 4105, 4931 and 5751 IU vitamin A kg(-1), respectively. Specific growth rate (SGR) and feed efficiency (FE) of gibel carpwere lower at 273 and 5751 IU kg(-1) vitamin A levels (P < 0.05). Hemoglobin content in blood, and the levels of plasma growth hormone (GH) and insulin-like growth factor I (IGF-1) were not significantly influenced by dietary vitamin A (P > 0.05). Although the apparent digestibility coefficients (ADCs) of dry matter, crude protein, crude lipid and energy were not influenced significantly (P > 0.05), high dietary vitamin A (5751 IU kg(-1)) decreased the activity of intestinal Na+ -K+ ATPase (P < 0.05). The plasma total antioxidative capacity (T-AOC) was improved at the levels of 1962 and 3155 IU vitamin A kg(-1) (P < 0.05). Vitamin A deficiency increased the activities of plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) (P < 0.05), and decreased the contents of whole body and liver crude lipid and the plasma cholesterol content (P < 0.05). Plasma cholesterol and vitamin A contents were significantly increased (P < 0.05) and then leveled off with the increasing of dietary vitamin A level. Broken-line regression between dietary vitamin A level and plasma cholesterol content or plasma vitamin A content indicated that the dietary vitamin A requirement of on-growing gibel carp was to be approximately 1716 IU kg(-1) and 2698 IU kg(-1), respectively. 2698 IU vitamin A kg(-1) diet is recommended for on-growing gibel carp in the present study. (C) 2016 Elsevier B.V. All rights reserved. |
