不同蛋白質含量下脂質及 n-3 高度不飽和脂肪酸添加對銀紋笛鯛成長效果之探討

Abstract

銀紋笛鯛為本省重要的經濟養殖魚種，至今對此魚種營養需求之研究仍非常有限。本研究探討於飼料中添加不同的蛋白質、脂質及n-3高度不飽和脂肪酸(n-3 HUFA)，對銀紋笛鯛於全海水養殖下適當的添加量，實驗結果如下： 1．各飼料組脂質含量相同時，45％蛋白質飼料之增重率、飼料效率均高於40％蛋白質飼料。 2. 40％及45％蛋白質飼料，隨著脂質含量增加，肌肉及肝臟脂質含量亦增加。各飼料組脂質含量相同時，45％蛋白質飼料肝臟脂質含量較40％蛋白質飼料為低。隨著脂質含量增加，肌肉及肝臟n-3 HUFA亦有增加之趨勢。 3．飼料以牛油調整n-3 HUFA於0.9-2.2％之間，0.9% n-3 HUFA飼料組增重率、飼料效率均最低。 4．以1.4% n-3 HUFA飼料組肌肉及肝臟脂質含量均最高，0.9% n-3 HUFA飼料組則最低。 5．肌肉中Σn-3 含量以2.2% n-3 HUFA飼料組較高，1.2% n-3 HUFA飼料組最低。肝臟中Σn-3含量則以2.2% n-3 HUFA飼料組最高，1.2% n-3 HUFA飼料組最低。 實驗結果，銀紋笛鯛於全海水養殖下，飼料中蛋白質在40~45%，脂質9-12％之間為適當添加量。當蛋白質在45%，脂質12％時n-3 HUFA含量在1.6％以上才能滿足銀紋笛鯛之營養需求。

Red snapper is the most important economically valuable aquaculture species in Taiwan. Studies on the nutritional requirements of this species are still lacking. The experiment was conducted to determine a suitable dietary composition for red snapper reared in seawater by feeding with various levels of protein, lipid and n-3 HUFA. The results are as follows: 1. At the same dietary lipid levels, the weight gain and feed efficiency were higher in fish fed diets 45% CP than those fed diets 40% CP. 2. As the dietary lipid increased, the accumulation of lipid in muscle and liver increased in fish fed diets 40% and 45% CP. At the same dietary lipid levels, fish fed diets 45% CP accumulated less lipid in liver than those fed diets 40% CP. With an increase in dietary lipid levels, the n-3 HUFA contents in muscle and liver also increased. 3. When the n-3 HL1FA content in diets were adjusted by beef tallow in the range from 0.9% to 2.2%, the lowest weight gain and feed efficiency were demostrated in fish fed diet 0.9% n-3 HUFA. 4. Fish fed diet 1.4% n-3 HUFA accumulated the most lipid in muscle and liver, that fed diet 0.9% n-3 HLTFA the least. 5. The highest ?n-3 ratio in muscle was demostrated in fish fed diet 2.2% n-3 HUFA. The highest ?n-3 ratio in liver was also found in fish fed diet 2.2% n-3 HUFA, and the lowest in fish fed diet 1.2% n-3 HUFA. These results indicated that the optimal dietary protein and lipid levels for red snapper reared in seawater are 40-45% and 9-12%. The n-3 HUFA contents in diets should be over 1.6% when dietary protein and lipid levels are fixed at 45% and 12%.