飼料中添加羽扇豆粉取代魚粉對海鱺成長之研究

Abstract

海鱺 cobia ( Rachycentron canadum ）為台灣重要箱網養殖魚種，是一種確立完全養殖技術的熱帶性海水魚類，成長快速一年內可達 4 至 6 公斤，換肉率約在 1 . 3－1 . 6 之間，為一高經濟性魚種，肉質鮮美，食用上以生魚片的方式消費。近年來在台灣、日本、海南島及東南亞地區，興起了養殖海鱺的熱潮，所使用的商業飼料中蛋白質來源均是由魚粉所提供，佔總成本的比例相當大。本研究是利用羽扇豆粉 ( Lupinus angustifolius ）取代海鱺飼料中的魚粉，在不影響海鱺成長的前提下，減少海鱺養殖的成本，提高台灣海鱺養殖產業之競爭力。 試驗用的海鱺購於佳冬的民間種苗繁殖場，經馴養7 天後分組採隨機取樣，於室外小型浮水箱網（ 120x70x70cm ）中進行實驗。本研究設計兩種實驗。第一是在飼料中添加 0一25 ％的羽扇豆粉以取代魚粉，探討羽扇豆的最佳取代比例。第二則是以不同方式處理羽扇豆，再加入飼料中取代魚粉，以進一步改良羽扇豆，增加取代比例。經過六週飼養後，試驗結果如下： 在飼料中添加0一25 ％的羽扇豆粉，結果以添加 20 ％羽扇豆粉組有最高的增重率。分析魚體脂肪含量，腹肌比背肌有較高的脂質，肝臟的脂質含量是隨羽扇豆粉取代比率升高而增加。以不同處理方式改良羽扇豆方面，以加熱方式處理羽扇豆粉，可使魚體增重率有效上升。以發酵方式處理羽扇豆粉，可有效提高魚體遊離胺基酸及風味胺基酸的蓄積。然而以補充 Met 及 Lys 兩種必需胺基酸的方式，可有效使取代比例達到 30 % ，而不影響海驪的成長。

Cobia (Rachycentron canadum) a tropical marine teleost, has been cage-cultured in Taiwan. The hatches technologies have recently been successful developed shows the expending growth potential and success of artificial propagation and larval production. The cobia grows rapidly grow up to 4—6 kg in one year with feed conversion ratios of 1.3 to 1.6. Cobia taste flesh and eat with sashimi for food, have high economic value. In recent years, cobia becomes a popular aquaculture fish in Taiwan, Japan, Hainan Island, and other southeaster Asia country. The main protein source in cobia feed is supplied by fish meal, is a big part of the cost of cobia feed. In a prerequisite of no affect in cobia growth, this study use lupin (Lupinus angustifolius) as a protein source to replace a part of fish meal to decrease the cost of cobia aquaculture and improve the competitiveness of cobia aquaculture in Taiwan. Cobia juveniles were obtained from PingTung, domesticated for a week and random sampling. Cobia were weight and stocked into small offshore cage in fish farm. Two growth trials were in the study. In the first trial, lupin was added to replace fish meal ranging between 0% to 25% in six diets to investigate the optimal replacement ratio of lupin in cobia diet. In the second trial, lupin was treated by different method and then replace fish meal in cobia diets to improve replacement ratio of lupin. In the first trial, the optimal replace ratio is 20% and have the highest weight gain. In fish body analysis, lipid of liver is increase with the raise of lupin replacement ratio. In the second trial, we use three methods to improve lupin. Heat treatment of Lupin can increase weight gain in 20% replacement ratio. Fermented lupin can increase free amino acid of fish body. The adding of extra amino acid of methionine and lysine can increase lupin replacement ratio.