微粒饲料中以微藻粉替代鱼油对牙鲆(Paralichthys olivaceus)稚鱼生长存活和脂肪酸组成的影响

Effects of Dietary Fish Oil Replacement by Microalgae in Microdiets on Growth Performance, Survival and Fatty Acid Profile of Japanese Flounder (Paralichthys olivaceus) Juveniles

中文关键词: 牙鲆稚鱼  微粒饲料  微藻  鱼油  脂肪酸

英文关键词: Japanese flounder (Paralichthys olivaceus) juveniles  Microdiets  Microalgae  Fish oil  Fatty acids

中文摘要:

      以18日龄的牙鲆(Paralichthys olivaceus)稚鱼为研究对象，通过11 d的生长实验，研究了添加不同比例的微藻粉替代鱼油对牙鲆稚鱼生长、存活率和脂肪酸组成的影响。以鱼油组(FO)为对照组，以裂壶藻粉(Schizochytrium sp.)、微绿球藻粉(Nannochloropsis sp.)和橄榄油替代不同比例的鱼油，配制成5组等氮等能的实验饲料，分别命名为鱼油组(FO)，50%混合替代组(M50)、100%混合替代组(M100)、100%裂壶藻橄榄油替代组(S100)、100%微绿球藻橄榄油替代组(N100)。结果显示,微藻粉替代鱼油对牙鲆稚鱼的生长无显著影响；含有裂壶藻的各饲料组(M50、M100、S100)成活率显著高于FO组和N100组(P˂0.05)；微藻粉替代鱼油不影响牙鲆稚鱼主要脂肪酸的组成；Person相关性分析发现，C14:0、C16:1n-7、C18:2n-6、C20:0、C18:3n-3、C22:0、C20:4n-3、EPA、C22:5n-6和DHA的百分含量均与其饲料中的百分含量呈显著正相关(P<0.05)；总饱和脂肪酸、总单不饱和脂肪酸、n-3多不饱和脂肪酸的百分含量以及DHA/EPA比率均与其饲料组成表现出显著正相关(P<0.05)。综上所述，微藻作为脂肪源替代鱼油完全可以满足牙鲆稚鱼的生长和发育，各种脂肪酸均可以被牙鲆稚鱼充分消化和吸收，并且添加两种微藻后提高了稚鱼的DHA含量和DHA/EPA比率，与鱼油对照组相比显著提高了牙鲆稚鱼的成活率。因此，以微藻替代鱼油在牙鲆稚鱼的培育中是可行的。

英文摘要:

      The aim of this study was to determine if algal products rich in DHA or EPA are able to completely replace fish oil in microdiets for marine fish juveniles, Japanese flounder Paralichthys olivaceus. To address the problem, an 11-d feeding experiment was carried out on 18-day old juveniles. The experimental subjects were fed with five groups of isolipidic and isoenergetic microdiets that were control group with fish oil (FO), 50% replacement group by mixed Schizochytrium sp., Nannochloropsis sp. and olive oil (M50), 100% replacement group (M100), 100% replacement group by Schizochytrium sp. and olive oil (S100), and 100% replacement group by Nannochloropsis sp. and olive oil (N100). The results showed that there were no significant effects of fish oil replacement with microalgae on growth. The groups containing Schizochytrium sp. (M50, M100 and S100) had higher survival rates than FO and N100 groups. No changes in the major fatty acid compositions of juveniles were observed with the replacement of fish oil by microalgae. In addition, Pearson correlation analysis showed that the percentage content of C14:0, C16:1n-7, C18:2n-6, C20:0, C18:3n-3, C22:0, C20:4n-3, EPA, C22:5n-6 and DHA in juveniles were significantly and positively correlative to those in diets (P<0.05). The same correlations were also observed for total saturated, monounsaturated and n-3 polyunsaturated fatty acids, and DHA/EPA ratio. In conclusion, fish oil replacement with microalgae as lipid sources can fully satisfy the growth and development in juvenile flounder, and fatty acids in microalgae can be effectively digested and absorbed. Furthermore, the addition of microalgae in diets enhanced the DHA content and DHA/EPA ratio in juveniles, and hence improved the survival. Therefore, the fish oil replacement with microalgae in the culture of Japanese flounder juveniles is feasible. This study will be helpful and suggestive for screening new lipid sources to replace strained fish oil resource.