Combined dietary effects of some antioxidants on rearing performance, antioxidant capacity, metabolic response and stress resistance of fish

• Main Authors: Angeles, Isagani Jr. Pablo, 安加林
• Other Authors: Chien, Yew-Hu
• Format: Others
• Language: en_US
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/04458918336546823348

博士 === 國立臺灣海洋大學 === 水產養殖學系 === 103 === Considering there are potential applications for antioxidants in aquaculture, as well as the fact there is a knowledge-gap about dietary effect of combined antioxidants on antioxidant capacity, metabolic response and stress resistance of fish following stress, thus this study aimed to provide a better understanding of the combined dietary effect of antioxidants in red striped snapper Lutjanus erythropterus, common carp Cyprinus carpio and nile tilapia Oreochromis niloticus. As a first step, the dietary effects of astaxanthin (AX) and oxidized oil (OX) on L. erythropterus were investigated in Chapter 4. Antioxidant capacity (superoxide dismutase, glutathione peroxidase and glutathione reductase) and metabolic response (glucose, triglycerides and lactate) were monitored at 0, 6, 12, 24, 48 and 72 h. AX- and (AX+OX)-fish had more improved antioxidant capacity and metabolic response than C- and OX-fish at 6 and 12 h. In Chapter 5, L. erythropterus were fed diets containing 80 mg/kg AX (8AX), 0.3 mg/kg Selenium (3SE), 500 mg/kg Vitamin E (5VE), combination of 8AX and 3SE (AXSE), combination of 8AX and 5VE (AXVE) or the basal diet-control (C) for seven days. The trends towards a higher antioxidant capacity and a lower metabolic response after salinity stress challenge test in treated diet over a basal diet, particularly in AXSE and AXVE, indicates that combination of antioxidants may not be met by un-supplemented practical diet in stressed fish. In Chapter 6 and 7, dietary effects of Quillay and/or Yucca on growth, antioxidant capacity, metabolic response and stress resistance of C. carpio and O. niloticus were investigated, respectively. In Chapter 6, fish were fed diets supplemented with 150 mg/kg Quillay (QS), 150 mg/kg Yucca (YS), the combination of 75 mg/kg Quillay and 75 mg/kg Yucca (M) or control diet (C) without addition of Quillay or Yucca for eight weeks. After rearing, fish were subjected to low dissolved oxygen stress and after a week, antioxidant capacity and metabolic response were analysed. QS-fish had the highest weight gain among all the treatments. Moreover, QS- and M-fish had 29 and 26% lower plasma glucose than C-fish, respectively. In Chapter 7, fish were fed diet supplemented with 150 mg/kg Quillay (QS), 150 mg/kg Yucca (YS), combination of 150 mg/kg Quillay and 150 mg/kg Yucca (M) or control diet (C) for six weeks. Final weight, weight gain and specific growth rate of M-fish were significantly higher than that of C-fish. Superoxide dismutase of M-fish was 48% lower than that of C-fish. Furthermore, glucose level of QS-, YS- and M-fish was 21, 30 and 37% lower than that of C-fish, respectively. Interestingly, percentage survival of YS- and M-fish was increased by 11 and 22% as compared to that of C-fish after 1-week hypoxic stress, respectively. Based on the present results, supplementation of AX in the diet significantly stabilized both antioxidant capacity and metabolic responses of L. erythropterus to some extent under a prooxidant circumstance associated with oxidized fish oil intake. In addition, combining antioxidants such as AXSE, AXVE and QS and YS improved antioxidant capacity and metabolic response of fish under stressed condition. In addition, combined antioxidants (Quillay and Yucca) also improved growth performance of O. niloticus.