探討富含DHA之裂殖壺藻粉取代飼料中魚油對點帶石斑稚魚成長表現、脂肪酸組成及免疫反應之影響

Studies on effects of fish oil replacement by DHA-rich Schizochytrium algae meal in diets on growth performance, tissue fatty acid composition and immune responses of juvenile grouper, Epinephelus coioides

卓立超(Li-Chao Zhuo)

指導教授 ： 林鈺鴻

國立屏東科技大學/農學院/水產養殖系所/碩士(2014年)

https://doi.org/10.6346/NPUST.2014.00185

摘要

論文摘要內容：

本研究目的為評估添加裂殖壺藻粉可否作為石斑魚飼料中DHA(二十二碳六烯酸)來源，以及裂殖壺藻粉或藻油可否取代魚油並評估其對石斑魚成長表現、脂肪酸組成、生理及免疫反應之影響。實驗一，全魚粉(F)及20%豆粉取代魚粉(FS)兩組飼料作為控制組，另以FS組飼料為基礎額外添加5%之裂殖壺藻粉(FS+5%)為實驗組。以循環水系統進行餵飼實驗，每缸放養12尾(平均初重為3.38 ± 0.04 g)，每組三重複，每日餵食兩次每次餵食至接近飽食，實驗為期8週。實驗成長數據顯示石斑魚之增重率、肥滿度及存活率在各組間並無顯著差異。血液分析方面血比容在各組間並無顯著差異，紅血球計數及血紅素濃度皆以添加藻粉5%的組別顯著高於FS組。魚體DHA及EPA(二十碳五烯酸)含量皆以FS+5%組顯著高於其他各組。DHA蓄積率以FS組顯著最高，F組次之，FS+5%最低。結果顯示，飼料中添加裂殖壺藻粉不影響石斑魚之成長表現，且有助於提高魚體內DHA含量。實驗二飼料以全魚粉(F)及豆粉取代飼料總蛋白40% (FS)兩組飼料為控制組，魚油取代組以藻粉(DM)或藻油(DO)取代FS組飼料中魚油DHA，DHA/EPA 2.5組為增加魚油取代組中藻粉(DM2.5)或藻油(DO2.5)含量，使飼料中DHA/EPA比值為2.5。以循環水系統進行餵飼實驗，每缸放養18尾石斑魚(平均初重為8.48 ± 0.06 g)，每組三重複，實驗為期8週，實驗期間平均攝食率為3%，每日餵食兩次，每兩週秤重一次換算餵食量。實驗結果顯示以裂殖壺藻取代魚油後不影響全魚體一般成分組成、血液生化反應及免疫反應，DO2.5組其成長表現顯著高於FS組且與F組無顯著差異。全魚體與背肌DHA含量隨飼料中DHA含量增加而上升，以DO2.5組顯著高於其它各組，以DM組顯著低於所有組別。肝臟DHA含量以DO2.5組顯著高於其它組別。DHA蓄積率以DM及DM2.5兩組最低，其次為DO2.5，F與DO組顯著高於其它各組。結果證實，石斑魚可利用裂殖壺藻粉或藻油做為DHA來源，但藻油利用效率優於藻粉。結果也顯示，以豆粉取代飼料總蛋白40%造成石斑魚成長低下，透過提高飼料中DHA/EPA比值可有效改善石斑魚成長表現。

關鍵字

石斑魚 ； 二十二碳六烯酸 ； 二十碳五烯酸 ； 裂殖壺藻

並列摘要

In order to evaluate whether Schizochytrium sp. algae meal can be used as a docosahexaenoic acid (DHA) source and the algal meal or its oil can replace fish oil in diet for grouper, the study was to investigate the effects of algal meal on growth, fatty acid profile, physiological and immune responses. In Experiment 1, three experimental diets including all fish meal (F), fishmeal replacement by 20% soybean meal (FS) and FS supplemented with 5% algal meal (FS+5%), were each fed to triplicate groups of fish (initial wt: 3.38 ± 0.04 g) in a recirculating system for 8 weeks. There were no significant differences in weight gain, condition factor, survival and hematocrit among all dietary treatments. Fish fed the FS+5% diet had higher (P < 0.05) red blood cell (RBC) count and hemoglobin (Hb) concentrations than fish fed FS diet. Whole body DHA and eicosapentaenoic acid (EPA) concentrations were higher in fish fed the FS+5% diet than those in other dietary treatments. DHA deposition was the highest in the FS group, followed by F group, and the lowest in FS+5% group. The results showed that grouper can utilize algal meal as a DHA source without negative effects on growth. In Experiment 2, six experimental diets including all fish meal (F) and replacement 40% protein by soybean meal (FS) as controls, fish oil replaced by algal meal (DM) or oil (DO) providing a DHA/EPA ratio of 1.5 (DM, DO) and 2.5 (DM2.5, DO2.5), were each fed to triplicate groups of fish (initial wt: 8.48 ± 0.06 g) in a recirculating system for 8 weeks. Whole body proximate composition, hematological and immune responses, were not affected by dietary treatments. Grouper fed the DO2.5 diet had higher weight gain than fish fed the diet FS group. Whole body and muscle DHA concentrations approximately increased by increasing dietary DHA level. Both parameters was higher in fish DO2.5 diet group but lower in DM group than other dietary groups. Hepatic DHA concentration was higher in fish fed the DO2.5 diet than other dietary treatments. DHA deposition was the lowest in DM and DM2.5 groups, followed by DO2.5 group, then the FS group, and the highest in F and DO group. The results demonstrated that grouper can utilize algal meal or oil as DHA source. The efficiency of algal oil is better than that of algal meal. Our results also indicated growth of grouper was depressed by replacing 40% fish meal by soybean meal and improved by increasing DHA/EPA ratio.

並列關鍵字

grouper (Epinephelus coioides) ； docosahexaenoic acid (DHA) ； eicosapentaenoic acid (EPA) ； algae meal (Schizochytrium sp.)

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