深水网箱和池塘养殖凡纳滨对虾肌肉营养成分的比较分析

为研究红景天(Rhodiola rosea)提取物对凡纳滨对虾(Litopenaeus vannamei)抗氧化系统及抵抗低盐度胁迫的影响，该实验设计0 mg·kg^–1、300 mg·kg^–1、1 000 mg·kg^–1和3 000 mg·kg^–1 4个红景天提取物水平饵料添加量，饲喂凡纳滨对虾28 d。然后进行72 h低盐度(10)胁迫实验，测试凡纳滨对虾肝胰腺总抗氧化能力(T-AOC)、谷胱甘肽过氧化物酶(GSH-Px)、过氧化氢酶(CAT)活性及GSH-Px、CAT基因表达水平。结果显示，在天然海水养殖条件下，GSH-Px、CAT活性和GSH-Px基因表达水平在某些时段被显著诱导(P<0.05)。低盐度胁迫24 h，对照组抗氧化指标相比于其他各组的变化幅度最大。低盐度胁迫72 h，红景天组T-AOC、CAT活性和GSH-Px、CAT基因表达水平均显著高于对照组(P<0.05)。双因素方差分析结果显示红景天提取物添加量与时间的交互效应对抗氧化指标的影响显著。结果表明，红景天提取物能够有效缓解胁迫初期凡纳滨对虾抗氧化指标的剧烈改变，明显提高胁迫后期机体的抗氧化系统功能，具有成为抗应激饲料添加剂的潜力。

Experiments on the growth of Penaeus vannamei boone

In order to investigate the effect of Rhodiola rosea extract on the antioxidant system and anti-low salinity stress of Litopenaeus vannamei, four levels of R.rosea extract were designed (0 mg·kg^–1, 300 mg·kg^–1, 1 000 mg·kg^–1 and 3 000 mg·kg^–1). We have fed the shrimps for 28 d and carried out a 72-hour low salinity (10) stress test to analyze the antioxidant capacity including total antioxidant status (T-AOC), glutathione peroxidase (GSH-Px), catalase (CAT) as well as gene expression of GSH-Px and CAT in hepatopancreas of shrimps. The results show that enzyme activities of GSH-Px and CAT and gene expression of GSH-Px were significantly induced in hepatopancreas of shrimps fed with R.rosea extract at different time intervals (P<0.05). The antioxidant indices of shrimps of the control group at low salinity stress at 24^th hour varied greater than those of shrimps of supplemental R.rosea groups. For the shrimps fed with dietary R.rosea extract at low salinity stress at 72^nd hour, the activities of T-AOC, CAT as well as gene expression of GSH-Px and CAT of hepatopancreas were significantly higher than those in the control group (P<0.05). The GLM analysis results show significant interaction between the effects of R.rosea extract level and time on the antioxidant indices. In conclusion, R.rosea extract can alleviate drastic variation of antioxidant indices in the hepatopancreas of shrimps at the early stress stage effectively. Besides, the antioxidant capacity of shrimps fed with supplemental R.rosea extract was significantly improved at the late stress stage. Thus, the R.rosea extract has the potential to become an anti-stress feed additive.