饲料中DHA含量对刺参成参生长及其体壁营养成分的影响

为确定刺参Apostichopus japonicus成参饲料中二十二碳六烯酸(DHA)的适宜添加量,采用摄食生长试验,探讨了在水温(12±2)℃下饲料中DHA含量(0.02%、0.30%、0.60%和1.20%)对体质量为(73.49±1.26)g的刺参成参生长和体壁营养成分的影响,试验共进行121 d。结果表明:饲料中DHA含量为0.60%时成参增重率最高,显著高于对照组(0.02%DHA)(P0.05);饲料中DHA水平显著影响成参体壁营养成分,摄食DHA含量为0.30%~1.20%饲料的刺参,其体壁中二十碳五烯酸(EPA)、DHA和n-3多不饱和脂肪酸(n-3 PUFA)含量无显著性差异(P0.05),但显著高于对照组(P0.05);饲料中添加DHA时,刺参体壁中DHA/EPA和n-3/n-6 PUFA显著升高(P0.05);0.30%DHA处理组刺参体壁中苯丙氨酸、酪氨酸、异亮氨酸、缬氨酸、蛋氨酸和总必需氨基酸含量最高,且显著高于对照组(P0.05),但总必需氨基酸/总非必需氨基酸各组间无显著性差异(P0.05)。研究表明,饲料中DHA含量为0.60%时成参的生长速率最快,DHA含量为0.30%时已具有较高的营养物质(必需脂肪酸和氨基酸)沉积率,成参对饲料中DHA的最适需求量为0.30%~0.60%(饲料干物质)。

Effects of dietary docosahexaenoic acid (DHA) content on growth performance and nutrient composition in body wall of adult sea cucumber Apostichopus japonicus

Adult sea cucumber Apostichopus japonicus with body weight of (73. 49±1. 26)g were reared in a 100 L tanks at stocking density of 20 individuals and fed diets containing 0. 02% , 0. 30% , 0. 60% and 1. 20% of doco-sahexaenoic acid (DHA) at water temperature of (12±2)℃ for 121 d to investigate the effects of dietary DHA lev-els on growth performance and nutrient composition in body wall of sea cucumber. The maximal weight gain rate (WGR) was observed in the sea cucumber fed diets containing 0. 60% DHA, significantly higher than that in the animals fed diet containing 0. 02% DHA (P<0. 05). Dietary DHA levels led to affect composition in body wall of sea cucumber, significantly higher eicosapentaenoic acid (EPA), DHA and n-3 polyunsaturated fatty acid (n-3 PUFA) concentrations in sea cucumber fed diets containing 0. 30% -1. 20% DHA than that in sea cucumber fed diets containing 0. 02% DHA (P<0. 05). The EPA/ DHA and n-3 / n-6 PUFA were significantly elevated with di-etary DHA level increase (P<0. 05). The maximal phenylalanine (Phe), tyrosine (Tyr), isoleucine (Ile), valine (Val), methionine (Met) and total essential amino acids (TEAAs) contents were observed in body wall of sea cu-cumber fed diet containing 0. 30% DHA, significantly higher than that in sea cucumber fed diet containing 0. 02%DHA (P<0. 05), without significant differences in the ratio of TEAA to total nonessential amino acids (TNEAAs) among the four groups. It is recommended that optimal DHA requirement be 0. 30% -0. 60% dry diet in adult sea cucumber, since 0. 60% dietary DHA results in the maximal WGR and deposition of essential fatty acids and amino acids in sea cucumber.