餌料對輪蟲 (Brachionus plicatilis) 體組成及餵飼育苗效果影響之研究

魚類幼苗所攝食的餌料生物營養組成，對其發育及成長影響重大。褶皺臂尾輪蟲 (Brachionus plicatilis) 體型小及適合大規模培養，為常見之水產養殖生物的餌料生物。本研究擬分別以光合菌、纖毛蟲、擬球藻及等鞭金藻四種餌料餵飼褶皺臂尾輪蟲，探討對輪蟲體組成脂質含量及組成分之影響，再以輪蟲投餵具高觀賞價值之棘頰海葵魚 (Premnas biaculeatus) 初孵化的仔魚三日，比較餵食以不同餌料為食的輪蟲之育苗效果。結果顯示，攝食纖毛蟲組或等鞭金藻組之輪蟲體單元不飽和脂肪酸相對含量，與光合菌組或擬球藻組之差異達顯著水準 (α = 0.05)；攝食擬球藻組或等鞭金藻組之輪蟲體多元不飽和脂肪酸相對含量與光合菌組或纖毛蟲組之差異達顯著水準 (α = 0.05)。花生四烯酸 (20:4n-6, Arachidonic acid, ARA)、二十碳五烯酸 (20:5n-3, eicosapentaenoic acid, EPA) 及二十二碳六烯酸 (22:6n-3, docosahexaenoic acid, DHA) 等對仔魚的發育有重要的影響，僅光合菌組之輪蟲未檢測到DHA，而纖毛蟲組的前兩種脂肪酸相對含量高於其他各組，差異達顯著水準 (α = 0.05)。此外，於培養輪蟲的實驗過程，輪蟲的攜卵個體比率隨天數增加而下降，餵食不同餌料一天後的輪蟲，纖毛蟲組未攜卵的個體比率最高，且未發現攜帶三顆卵的輪蟲。以攝食不同餌料的輪蟲餵飼初孵化棘頰海葵魚仔魚三天後，纖毛蟲組的仔魚活存率最低，但其全長及標準體長雖然在飼育第一天後顯著低於其他各組，但第二天後與各組即無顯著差異 (α = 0.05)。以攝食不同餌料的輪蟲飼育仔魚三天後，仔魚的生存活力指數以纖毛蟲組為最低，差異達顯著水準。對低溫緊迫之耐受性則四組差異皆未達顯著水準 (α = 0.05)。綜上所述，光合菌、擬球藻及等鞭金藻皆適合投餵輪蟲並以之作為棘頰海葵魚仔魚的餌料，其育苗效果較以纖毛蟲為餌料的輪蟲佳；但若要以纖毛蟲當作輪蟲餌料時，則餌料量需充足並改善輪蟲體營養組成，以提升仔魚發育及成長的效益。

關鍵字

輪蟲；脂肪酸；棘頰海葵魚；育苗

並列摘要

There are significant impacts arise from the nutritional composition of the live food on fish larvae development and growth. The rotifer, Brachionus plicatilis, is a common live food for aquaculture organisms due to small in size and suitable for large-scale cultivation. In this study, the rotifer B. plicatilis is fed with four diets respectively, including photosynthetic bacteria Rhodovulum sulfidophilum, ciliates, two microalgae Nannochloropsis oculata and Isochrysis galbana, to investigate the effects of diets on the lipid content and composition of rotifer. The rotifers ingested various diets for three days are then fed to newly hatched larvae of spine-cheek anemonefish Premnas biaculeatus, a high value marine ornamental fish, to further evaluate the benefit in larvae culture. The results showed that the relative content of monounsaturated fatty acids in rotifers fed with ciliates or I. galbana are respectively significantly different from that with R. sulfidophilum or N. oculata(α = 0.05). Relative content of polyunsaturated fatty acids in rotifers fed with N. oculata or I. galbana are respectively significantly different from that with R. sulfidophilum or ciliate (α = 0.05). Arachidonic acid (20:4n-6, ARA), eicosapentaenoic acid (20:5n-3, EPA) and docosahexaenoic acid (22:6n-3, DHA) have important effects on the development of fish larvae. The content of DHA in rotifers fed with R. sulfidophilum is under detectable level, while the relative contents of ARA and EPA in rotifers fed with ciliate are significantly higher than those fed with the other diets (α = 0.05). The ratio of rotifer individual carrying egg decrease when feeding time extends. The ratio of rotifer carring no egg and fed with ciliate for one day is highest than those fed with the other diets, and furthermore none carrying three eggs. The survival rate and survival activity index (SAI) of fish larvae ingest rotifer fed with ciliate for three days are significantly less than the others. The total length (TL) and standard length (SL) of these larvae are also significantly shorter than the others after one day of feeding, nevertheless, there is no significantly difference among the larvae ingest rotifer fed with various diets respectively after two days of feeding (α = 0.05). There is no significant difference in the tolerance to low water temperature among these larvae ingest various rotifers (α = 0.05). In summary, photosynthetic bacteria R. sulfidophilum and two microalgae inluding N. oculata and I. galbana are more suitable as the diets for rotifer when fed to spine-cheek anemonefish to acquire more culture benefit than ciliates. However, if ciliates are employed as rotifer bait, the amount of ciliates should be sufficient for ingestion by rotifer, and the nutritional composition of rotifer have to be further improved to increase the benefit in larvae development and growth.