甘草次酸对斑点叉尾（鱼回）免疫应激下血浆抗氧化酶和免疫指标的影响

为探讨斑点叉尾(鮰)免疫应激状态下血浆抗氧化酶和免疫指标的变化,并研究甘草次酸对斑点叉尾(鮰)免疫应激的调控机制,实验设计两组,每组6个重复:1)对照组,饲喂基础饲料;2)GA组,饲喂含0.15 g/kg甘草次酸饲料,养殖8周后,腹腔注射大肠杆菌脂多糖(LPS),分别在注射后0、3、6、12、24、48 h采集血液和肝脏组织,进行红细胞、白细胞计数,分离血浆后检测血浆皮质醇、溶菌酶、ACH50、谷草转氨酶、谷丙转氨酶、碱性磷酸酶活性,肝脏匀浆液检测SOD、MDA和CAT抗氧化酶活性.结果显示,在腹腔注射LPS后,血浆溶菌酶、皮质醇、谷草转氨酶、谷丙转氨酶、ACH50、SOD均呈现先升高后下降的趋势,白细胞计数、血浆CAT呈现先下降后升高的趋势;饲料中添加0.15 g/kg甘草次酸显著抑制了各指标变化,缩短了由LPS诱导产生各指标变化的恢复时间.研究表明,腹腔注射LPS使斑点叉尾(鮰)产生免疫应激,并在注射后6～12h达到顶峰;饲料中添加0.15 g/kg甘草次酸可以有效抑制由LPS诱导的免疫应激反应.

Effect of glycyrrhetinic acid (GA) on the physiological responses and immunoreactions of channel catfish (Ictalurus punctatus) injection lipopolysaccharide (LPS)

Glycyrrhetinic acid (GA), which is a main active principal constituent of liquorice, is extensively used as antibacterial and anti-inflammatory Chinese medicine. This study was carried out to evaluate the effects of GA on the oxidative stress of Ictalurus punctatus injection lipopolysaccharide (LPS). The fish were randomly divided into two groups:a control group (fed a standard diet) and a treatment group (standard diet supplemented with 0.15 mg/kg GA) and fed for 8 weeks. We then challenged the fish with LPS and recorded changes in red and white blood cell counts (RBC and WBC), plasma cortisol, lysozyme, ACH50, aspartate aminotransferase (AST), alanine aminotransferase (ALT) and hepatic catalase (CAT), superoxide dismutase (SOD) and malondialdehyde (MDA) for a period of 48 h. Supplementation with 0.15 g/kg GA significantly increased plasma lysozyme activity before infection, plasma ACH50 activity at 6 h after infection, WBC hepatic at 6 h after infection, CAT activity 24 h after infection, hepatic SOD activity before and after infection. In addition, the supplemented group had decreased levels of plasma AST and ALT activities 6 h after infection, hepatic CAT 3 h after infection, hepatic MDA 24 and 48 h after infection. Our results suggest that ingestion of a basal diet supplemented with 0.15 g/kg GA prevents LPS-induced immunological challenges response by regulating key enzyme activities, and challenged with LPS (2.0 mg/kg) affect physiological responses and immunoreactions of channel catfish.