饲料中添加浒苔对黄斑蓝子鱼生长性能与生理生化指标的影响

试验用黄斑蓝子鱼(Siganus canaliculatus)幼鱼捕自汕头大学南澳临海试验站附近海域, 在海上网箱中暂养半个月后将其转入室内水族缸(容积200 L)中驯养2周, 饵料为自制配合饲料。新鲜浒苔(Enteromorpha prolifera)从汕头市南澳县盐田采得, 用水清洗后晒干, 经小型粉碎机粉碎, 过60目筛, 制成海藻干粉。选取体质量约23 g黄斑蓝子鱼进行试验。在蛋白水平32%、脂肪水平8%的情况下, 配制6种配合饲料, 其中3种饲料分别添加5%、10%和15%的浒苔干粉, 另2种添加10%、15% 浒苔的饲料中还添加0.2%非淀粉多糖酶(NSP酶), 对照组饲料不添加浒苔。养殖试验周期为8周。结果显示: 与对照组相比, 5%浒苔组鱼的生长性能不受影响(P>0.05), 但10%和15％浒苔组鱼的生长性能显著降低(P<0.05); 然而, 在添加0.2% NSP酶的情况下, 10％和15%浒苔组鱼的生长性能与对照组相比无显著差异(P>0.05)。各饲料组鱼的成活率及全鱼的水分、蛋白、脂肪、灰分含量无显著差异(P>0.05)。与对照组鱼相比, 浒苔饲料组鱼肝和肌肉中的过氧化氢酶及谷胱甘肽过氧物酶的活性增高, 丙二醛含量降低。结果表明, 黄斑蓝子鱼配合饲料中浒苔的添加比例可达5%; 在加入一定量NSP酶的情况下, 其添加比例可达10%～15%。饲料中添加适当比例的浒苔可提高鱼体的抗氧化能力。本研究旨在探讨浒苔作为黄斑蓝子鱼配合饲料原料加以利用的可行性, 为浒苔资源开辟一条有效的利用途径, 并为研发高效、低成本蓝子鱼配合饲料提供指导和依据。

Effects of dietary seaweed Enteromorpha prolifera on growth performance, physiological and biochemical characteristics of rabbitfish Siganus canaliculatus

We evaluated the feasibility of using seaweed Enteromorpha prolifera as a dietary ingredient for the rabbitfish Siganus canaliculatus. We formulated five compound feeds with different levels of dried E. prolifera, but all with 32% total protein and 8% lipid. Three of the diets contained 5%, 10%, or 15% dried seaweed. Two diets contained 10% or 15% dried seaweed supplemented with 0.2% non-starch polysaccharide enzymes(NSP enzymes). The control diet had no seaweed. Groups of rabbitfish juveniles were fed one of the diets for 8 weeks. We measured growth and physiological and biochemical indexes to determine the optimum dietary ratio of E. prolifera. The addition of 5% seaweed had no effect on growth relative to the control group(P > 0.05), whereas growth declined significantly in fish fed diets with 10% or 15% seaweed(P < 0.05). However, there was no difference in growth between fish fed diets with 10% or 15% seaweed group and 0.2% NSP enzyme and the control group(P>0.05). Furthermore, there was no significant difference in survival or the whole fish moisture, protein, fat, and ash contents among the groups(P>0.05). The activities of hydrogen peroxide enzyme and glutathione peroxidase increased, whereas malondialdehyde content decreased in the liver and muscle of fish fed diets containing seaweed. Our results suggest that the optimal proportion of E. prolifera in rabbitfish diet is 5%, or between 10%-15% if supplemented with 0.2% NSP enzymes. The addition of seaweed in diets may also increase the antioxidant capacity.