生物絮团对仿刺参幼参生长与酶活性的影响

 以仿刺参幼参(Apostichopus japonicus)为研究对象, 采用发酵法培养生物絮团, 在室内塑料水槽中进行为期30 d的幼参培育实验。选择蔗糖作为碳源, 并设置饵料替代(0、10%、15%和20%共计4个梯度)和换水频次 (3 d/次和7 d/次两种)正交实验, 分析其对幼参生长、成活及其体内消化酶、免疫性酶活性和可溶性蛋白含量的影响, 为生物絮团培育幼参技术确定最佳投饵量和换水频次等参数提供依据。结果表明, 实验期间处理组淀粉酶(AMS)活性总体均高于对照组, 生物絮团可以提高幼参淀粉酶活性; 第15天时, 每3 d换水1次并替代15%饵料的处理组幼参体壁中超氧化物歧化酶(SOD, 32.9 U/mg prot)及碱性磷酸酶(AKP, 146.8 U/g prot)活性高于其他3组和对照组(P<0.05); 而每7 d换水1次且替代20%饵料组SOD(35.3 U/mg prot)及AKP酶活性(158.8 U/g prot)均明显高于对照组(P< 0.05)。第30天时, 每7 d换水1次且替代10%饵料组幼参淀粉酶和SOD活性均比15 d有所升高, 尤其AKP活性明显升高; 其特定生长率(4.12 %/d)与成活率(98.9%)均最高。每7 d换水1次且替代15%饵料组体壁中可溶性蛋白含量(10.9 mg/g)最高, 均明显高于对照组(P <0.05); 但与替代10%饵料组(9.3 mg/g)差异不显著。而每3 d换水1次且替代20%饵料组幼参成活率(91.8%)最低, 其可溶性蛋白含量与其他3组和对照组差异不显著(P>0.05)。适当降低换水频次和减少投饵量适于生物絮团系统中幼参的生长、存活与可溶性蛋白质积累。

Effect of bioflocs on enzyme activities and growth performance of juvenile sea cucumber Apostichopus japonicus

 We evaluated the effects of bioflocs on digestibility, immunity, growth, and survival of juvenile sea cucumber Apostichopus japonicus during a 30 d feeding trial. Animals were fed one of four diets in which 0, 10%, 15% or 20% of the carbon source was replaced with sucrose. Additionally, we tested the effect of water-exchange frequency (3 or 7 d). The experiment was set up using an orthogonal design and we measured growth performance, survival, enzyme activities, and soluble protein content. The activities of amylase(AMS) in the experimental groups were generally higher than in the control, indicating that the bioflocs stimulate amylase activity in A. japonicus. On day 15, superoxide dismutase(SOD, 32.9 U/mg prot)and alkaline phosphatase (AKP, 146.8 U/g prot)activity was higher in the 3 d/15% group than in the other three groups and the control(P<0.05). Similarly, SOD (35.3U/mg prot) and AKP(158.8 U/g prot) activity was higher in the7 d/20% group than in the other three groups and the control group(P<0.05). AMS and SOD activity were higher on day 30 than on day 15 in the 7 d/10% group and the increase in AKP activity was particularly significant. The growth rate (4.12%/d) and survival (98.9%) were highest in this group, whereas survival was lowest (91.8%) in the 3 d/20% group. Furthermore, the soluble protein content in the body wall of A. japonicus was not different from the other three groups and the control (P>0.05).The soluble protein content (10.9 mg/g) was higher in the 7 d/ 15% group than in the control(P<0.05), but was not different from the 7 d/10% group. Thus, our results suggest that areduction inwater exchanging frequency and feeding quantity may be beneficial to growth performance and soluble protein accumulation in A. japonicus. Our results provide a basis for determining the optimal feeding quantity and water-exchanging frequency for juvenile sea cucumber in biofloc technology systems.