Dietary alanyl-glutamine and vitamin E supplements could considerably promote the expression of GPx and PPAR alpha genes, antioxidation, feed utilization, growth, and improve composition of juvenile cobia

作者：Ding, Zhaokun; Li, Weifeng; Huang, Jinhua; Yi, Bo; Xu, Youqing^*

来源：Aquaculture, 2017, 470: 95-102.

DOI：10.1016/j.aquaculture.2016.12.015

• Alanyl-glutamine dipeptide
• Vitamin E
• Peroxisome proliferator-activated receptor alpha gene
• Glutathione peroxidase gene
• Cobia

This experiment was conducted to study the effect of various dietary alanyl-glutamine dipeptide (AGD) and/or vitamin E (VE) supplement(s) on the expression of glutathione peroxidase (GPx) and peroxisome proliferator-activated receptor alpha (PPAR alpha) genes, antioxidation, feed utilization, growth, and composition of juvenile cobia (Rachycentron canadum). Six groups of the juveniles in triplicate were fed for 12 weeks using 6 diets: Control diet (DO) contained only basic ingredients; Diet 1 (D1) contained single added AGD 10 g kg(-1) dried feed; Diet 2 (D2) contained single added VE 100 IU kg(-1) dried feed; Diet 3 (D3) contained added AGD 10 g kg(-1) dried feed and VE 100 IU kg(-1) dried feed; Diet 4 (D4) contained added AGD 5 g kg(-1) dried feed and VE 50 IU kg(-1) dried feed; Diet 5 (D5) contained added AGD 2.5 g kg(-1) dried feed and VE 25 IU kg(-1) dried feed. The juveniles were sampled randomly for analysis in week 0 and week 12. The main results were as follows: the diets with combined AGD and VE supplements could considerably promote feed utilization, growth, and improve composition of the juveniles; the combined AGD and VE supplements could significantly promote (P < 0.05) glutathione peroxidase (GPx), catalase (CAT), glutathione S-transferase (GST), total antioxidant capacity (T-AOC), the expression of PPARa and GPx genes, and significantly decrease (P < 0.05) malondialdehyde (MDA) in the liver and muscle of the juveniles; the effect of AGD supplement alone on the expression of GPx gene was significantly greater (P < 0.05) than that of VE supplement alone in the liver; whereas the effect of VE supplement alone on the expression of PPARa gene was significantly greater (P < 0.05) than that of AGD supplement alone in the liver and muscle. We concluded that the combined AGD and VE supplements could cooperate and considerably promote the expression of GPx and PPARa) genes, antioxidation, feed utilization, growth, and improve composition of juvenile cobia; the optimum was D4, with 5 g of AGD and 50 IU of VE added per kg of dried feed.
Statement of relevance: There is a need to assess light effect on lice settlement in controlled conditions due to conflicting results. We analyzed lice settlement while taking into account preexisting fin erosion and fish size. Findings confirm that light is not requirement for lice infestation.

• 出版日期2017-3-1
• 单位广西大学