Effects og dietary lipid levels and essential fatty acids on growth of juvenile Americao eels, Anguilla rostrata

• Main Authors: YU, Chun-Shin, 余俊欣
• Other Authors: Liao Wen-Liang
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/55835699224769421571

碩士 === 國立臺灣大學 === 漁業科學研究所 === 85 === Lipids play an important role as dietary energy sources and offer theessential fatty acids (EFA) to fish bodies. The eels, considered as warmwater carnivorous fish, are poorly capable to utilize carbohydrates buthighly capable to increase body-fat deposition. It is important to comprehendthe lipid requirement of eel species. This study is focused on the effectsof dietary lipid levels and essential fatty acids on the growth of juvenileAmerican eels, Anguilla rostrata. The study was performed in two parts. The chapter one, two feedingexperiments were conducted to determine the optimal dietary lipid level ofjuwenile American eels by feeding diets containing various lipid levels. Theresults of both experiment Ⅰ and Ⅱ showed that the group fed with the dietssupplemented 3 % oil (protein / energy ratios around 100 mg / kcal) had thebest percent gain and feed efficiency. In addition, the fatty acids of muscleshad shown that Σn-3 and Σn-6 fatty acids increased when the group fed withthe higher oil diets. The chapter two, two feeding experiments were conducted to clarify therequirement of essential fatty acids of juvenile American eels by feedingdiets containing various fatty acids. The results of the experiment Ⅲ, thebest percent gain and feed efficiency were obtained in the fish fed the dietcontaining 1 % 18:2n-6 or 1 % 18:3n-3. In the polar fatty acids from liver,the ratio of 20:3n-9 / 22:6n-3 and 20:3n-9 / 20:4n-6 were both less than 0.4and 0.6 when fish fed the diet containing 1 % 18:2n-6 or both 0.5 % 18:2n-6and 0.5 % 18:3n-3. In the experiment Ⅳ was not satisfactory due to the fishinfected with Dactylogyrus sp. which caused a high mortality. However, thegroup fed with the diet containing 1 % 18:2n-6 had the best percent gain andfeed efficiency. In the polar fatty acids from liver, the ratio of 20:3n-9 / 22:6n-3 and 20:3n-9 / 20:4n-6 were both less than 0.4 and 0.6 when fish fedthe diet containing 1 % 18:2n-6 or both 0.5 % 18:2n-6 and 0.5 % 18:3n-3. Thus, the optimal dietary lipid level for the growth of juvenile Americaneels was found to be around 9∼10 % (protein / energy ratios around 100 mg /kcal). Besides, 1 % 18:2n-6 or both 0.5 % 18:2n-6 and 0.5 % 18:3n-3 couldsatisfy the requirement of essential fatty acids of juvenile American eels.