飼料中添加螺旋藻粉及重組類胰島素成長因I 對菊池氏細鯽成長之影響

Abstract

菊池氏細鯽(Aphyocypris kikuchii)，為台灣特有種。常見於台灣東部的宜蘭、花蓮及台東的河川、湖沼等流速較緩的水域中。但是近年來由於人們對於其需求大增而過度捕撈，加上棲地破壞，使其於天然水域中大量減少。目前花蓮縣水產培育所已透過人工苗的生產放流進行復育，對此魚種飼料的開發將有助於復育工作。螺旋藻(Spirulina platensis)有很高的蛋白質含量(60-70%)，胺基酸組成與其他成本較高之飼料原料相似，另亦含豐富的維他命、礦物質、必需脂肪酸(γ-亞麻油酸，γ-linolenic acid—GLA)以及抗氧化色素例如類胡蘿蔔素，因此經常被用作飼料營養添加或甚至取代某些原料。 實驗一探討飼料中添加螺旋藻粉（Spirulina platensis）取代玉米筋質粉對菊池氏細鯽魚成長之影響。共有5組，分別為－玉米筋質粉20%、螺旋藻粉0%，Spi.0；玉米筋質粉15%、螺旋藻粉5%，Spi.5；玉米筋質粉10%、螺旋藻粉10%，Spi.10；玉米筋質粉5%、螺旋藻粉15%，Spi.15；玉米筋質粉0%、螺旋藻粉20%，Spi.20。實驗的菊池氏細鯽平均初始體重0.60 ± 0.09g，每組15隻3個重複為期9週。結果顯示，Spi.15組有最高增重率、飼料效率、蛋白質效率及每日氮增量，皆較對照組佳，各組皆無死亡。 由於文獻中皆指出此魚種有生長較緩慢的情形，因此於實驗二各添加0.5%重組類胰島素成長因子I，飼料其餘成分比例皆與實驗一各組相同，探討對菊池氏細鯽成長的影響。實驗魚隻平均初始體重0.78±0.04g，每組10隻3個重複為期9週。結果顯示，Spi.15組同樣於各項數據有最佳表現。 實驗結果顯示，無論飼料中是否添加成長因子，以螺旋藻粉含量15%的Spi.15組之各項數據皆為最佳，而添加重組類胰島素成長因子I的實驗二各組皆較實驗一的相對應組別有明顯較佳增重率。因此推測以螺旋藻粉取代15%的玉米筋質粉對菊池氏細鯽有最佳成長效果，且若飼料中添加微量成長因子對菊池氏細鯽的成長亦有明顯助益。

The first part of this study evaluate the effects of diets containing 20% of corn gluten meal, and substituting 0, 25, 50, 75 and 100% Spirulina platensis for that, i.e. Spirulina platensis accounts for 0, 5, 10, 15, 20% of the feed formula respectively, on growth performance of kikuchii minnow (Aphyocypris kikuchii). A completely randomized experimental design is developed with the abovementioned five treatments and three replicates. 225 kikuchii minnow with average initial weight of 0.60 ± 0.09g are assigned to 5 experimental tanks. The experiment lasts for 9 weeks. Kikuchii minnows fed with 15% S. platensis show a significantly higher weight gain､feed efficiency､protein efficiency ratio and daily N increase than those which are fed with 0% S. platensis (p＜0.05). According to previous studies, kikuchii minnow often has a relatively lower growth rate. That further leads to the second part of this study, which not only contains the same 5 groups of feed formula as the first one, but supplements each one with 0.5% recombinant insulin-like growth factor Ⅰ(IGF-Ⅰ). The average initial weight of 150 kikuchii minnow is 0.78±0.04g. The group fed with 15% S. platensis also shows significantly higher performances in all parameters than those which are fed with 0% S. platensis (p＜0.05). Both parts of the study show no casualty. The present results demonstrate that S. platensis could be introduced as a substitute in kikuchii minnow diets without compromising their growth and might even be a booster. The improved growth and feed utilization are probably due to enhancement of protein assimilation. As the results indicate, the proper dietary Spirulina meal level is 15%. In addition, supplementing with 0.5% IGF-Ⅰwill cast a positive effect on their growth performance.