绿原酸诱导凡纳滨对虾抗氧化功能及抵御低盐度胁迫的响应

选择健康、均匀, 体质量为(6.74 ± 0.08) g的凡纳滨对虾(Litopenaeus vannamei),  将360尾随机分为4组, 分别投喂含有0 mg/kg、100 mg/kg、200 mg/kg和400 mg/kg绿原酸的饲料28 d, 随后将对虾从盐度为32的天然海水直接转移至盐度为10的海水中暴露72 h, 测定对虾肝胰腺TAS、GPx、CAT活力和GPx、CAT基因表达水平。结果显示, 在天然海水养殖条件下, 绿原酸对凡纳滨对虾肝胰腺TAS、GPx活性无明显影响, 但投喂含有绿原酸的饲料28 d, 对虾肝胰腺GPx、CAT和GPx、CAT基因表达水平显著高于D0组(P<0.05), 以D2组GPx活性和GPx、CAT基因表达水平最高, 分别为164.29 U/mgprot和1.61、2.14倍。低盐度胁迫24 h, D0组对虾抗氧化反应表现在TAS、GPx活性和GPx基因表达水平较28 d显著升高(P<0.05), 分别增加了31.30%、27.96%和170%, 而绿原酸各组对虾肝胰腺TAS、GPx活性和GPx基因表达水平显著低于D0组(P<0.05), 说明绿原酸可有效缓解低盐度胁迫下对虾抗氧化系统酶活性的剧烈波动。低盐度胁迫72 h, 绿原酸各组对虾肝胰腺TAS、GPx、CAT活性及CAT基因表达水平均明显高于D0组。上述结果表明绿原酸能够诱导凡纳滨对虾的抗氧化系统功能, 在凡纳滨对虾抵抗低盐度胁迫中发挥着重要的作用。本研究旨为开发绿色植物提取物在对虾养殖中的应用, 解决盐度胁迫对机体造成的氧化损伤提供理论依据。

Antioxidant activity and resistance to low-salinity stress in Litopenaeus vannamei induced by chlorogenic acid

To investigate the effects of chlorogenic acid on the antioxidant activity and resistance to low-salinity stress in Litopenaeus vannamei, 360 shrimps were randomly divided into four groups and fed four diets containing 0, 100, 200 and 400 mg chlorogenic acid/kg(diet). After feeding for 28 days, all shrimps were subjected to an acute salinity change from 32 to 10 for 72 h. Total antioxidant status (TAS), glutathione peroxidase (GPx) and catalase (CAT) levels, and expression of the GPx and CAT genes in the hepatopancreas of L. vannamei, were analyzed. The results demonstrated that supplemental chlorogenic acid had no effect on TAS or on GPx activity in the hepatopancreas when shrimp were cultured in natural seawater. Compared with the D0 control group, however, dietary supplemental chlorogenic acid significantly increased GPx and CAT activities, and expression of the GPx and CAT gene in the hepatopancreas after feeding the shrimp for 28 days (P<0.05). GPx activity and gene expressions of GPx and CAT in the D2 group 200 mg (chlorogenic acid)/kg(diet) ] were higher than in the other groups, at 164.29 U/mg(prot) and 1.61 and 2.14 fold, respectively. After low-salinity stress for 24 h, the antioxidant response was characterized by higher TAS, greater GPx activity and higher gene expression of GPx in the hepatopancreas compared with levels found at 28 days (P<0.05), i.e. an increase of 31.30%, 27.96% and 170%, respectively. Moreover, TAS, GPx activity and GPx gene expression in the hepatopancreas in shrimp that were fed diets supplemented with chlorogenic acid were lower than those of the D0 group (P<0.05). The results indicate that chlorogenic acid could effectively inhibit dramatic changes in antioxidant enzyme system activities of shrimp exposed to low-salinity stress. After low-salinity stress for 72 h, TAS, GPx and CAT activities and GPx gene expression in the hepatopancreas of shrimp that were fed chlorogenic acid were higher than the D0 group. In conclusion, chlorogenic acid induces antioxidant system activity and plays an important role in resistance to low-salinity stress in L. vannamei.