大黄葸醌提取物对建鲤抗应激及生长的影响

将750尾建鲤随机分成5组,第1组为对照组,投喂基础日粮,另外4组为试验组,投喂基础日粮中分别添加0．5％、1．0％、2．0％、4．0％大黄蒽醌提取物。从2005年7月到9月连续投喂70d后,对鱼体进行高密度应激,测定其生长、应激前后血液皮质醇、血糖、溶菌酶等变化。结果表明：与对照组相比,应激前添加大黄葸醌提取物提高了鱼体增重率、特定生长率、鱼体丰满度、血液溶菌酶活性,降低了饵料系数与鱼体死亡率,但是与大黄葸醌提取物的添加水平不成线性关系,其中2．0％试验组还显著降低了血液皮质醇。高密度应激1d后,各组血液中的皮质醇、血糖、溶菌酶都有不同程度的增加,其中对照组最高,添加1．0％和2．0％大黄蒽醌提取物的试验组相对较低。应激前后各组鱼的攻毒试验表明：除应激前添加1．0％和2．0％大黄蒽醌提取物的组没有死鱼外,其它各组都有死鱼,其中对照组死亡率最高。因此添加1．0％-2．0％大黄蒽醌提取物提高了机体抗应激能力,并对病原菌感染起一定的保护作用,促进了鱼体生长。     

大黄蒽醌提取物对饲养建鲤生长的影响

将750尾建鲤(Cyprinus carpio var.jian)随机分成5组。一组为对照组,投喂基础日粮。另外4组为实验组,投喂的基础日粮中分别添加0.5%、1.0%、2.0%、4.0%大黄蒽醌提取物。连续投喂70d后,测定鱼的生长、免疫相关因子、肠道菌数量及肉质等。结果表明,与对照组相比,添加大黄蒽醌提取物提高了鱼体增重率、饲料转化效率、溶菌酶活性、一氧化氮浓度、超氧化物歧化酶活性,促进了肠道有益菌增加,抑制有害菌生长,降低了丙二醛含量及鱼体死亡率,但是与大黄蒽醌提取物的添加水平不成线性关系;其中1.0%实验组肝胰脏溶菌酶与超氧化物歧化酶活性最高,血清丙二醛含量最低;2.0%实验组增重率、血清一氧化氮浓度与超氧化物歧化酶活性、肝胰脏一氧化氮浓度、肠道乳酸杆菌数量最高;添加1.0%~2.0%大黄蒽醌提取物显著提高了肌肉粗脂肪含量。因此,添加1.0%~2.0%大黄蒽醌提取物能改善肠道的微生态平衡,提高机体免疫机能,改善肉质,促进鱼体生长。     

虾头提取物对凡纳滨对虾生长和免疫因子的影响

以添加不同量虾头提取物(0、1.0%、1.5%、2.0%、2.5%、3.0%)的饲料投喂初体质量为6.35±0.38 g的凡纳滨对虾49 d,研究其对对虾的生长及免疫因子的影响。各组凡纳滨对虾的生长及体成分组成没有显著差异。与对照组相比,1.5%~3.0%添加量组对虾血清中的ACP活力明显提高;2.0%~3.0%添加量组对虾血清中的AKP活力明显提高;各添加量组对虾血清中的PO活力都有明显提高。实验结果表明,添加适当剂量的虾头提取物可以增强凡纳滨对虾的免疫能力。     

饲料蛋白水平对低温应激下吉富罗非鱼血清生化指标和HSP70 mRNA表达的影响

在水温27℃条件下, 分别对吉富罗非鱼(27.642.79) g投喂3组不同蛋白水平的饲料, 养殖周期56d。饲养结束后, 进行14℃低温应激实验, 研究低温应激后0-24h内, 鱼体血清生化指标与肝脏HSP70　mRNA表达量的变化。结果表明, 短期投喂50%蛋白水平的饲料可以提高罗非鱼血清中葡萄糖、总蛋白、甘油三酯与胆固醇水平以及血清谷丙转氨酶与谷草转氨酶活力。在低温应激后, 50%蛋白组血清葡萄糖、总蛋白、甘油三酯与胆固醇水平呈下降趋势, 而血清皮质醇水平与谷草转氨酶活力表现为先上升后下降变化。25%和38%蛋白组血清葡萄糖水平与谷丙转氨酶活力在应激期间呈上升趋势, 而谷草转氨酶与碱性磷酸酶活力和总蛋白与胆固醇水平呈先上升后下降变化。各实验组溶菌酶活力与肝脏HSP70 mRNA的表达量呈先上升后下降的变化。由此可知, 短期投喂高蛋白饲料可以提高罗非鱼血液中蛋白、血糖与脂肪含量, 增强鱼体抗应激能力, 同时, 高蛋白水平的饲料也会引起肝脏产生分解压力以及增加饲料成本。在生产中, 需要根据实际需要合理确定饲料的蛋白含量。       

谷氨酰胺对半滑舌鳎稚鱼非特异性免疫相关酶活力和低氧应激后HIF-1表达的影响

为探讨饲料中谷氨酰胺对半滑舌鳎稚鱼非特异性免疫以及低氧应激后HIF-1表达的影响, 实验共设计了4种谷氨酰胺添加量分别为0、0.5%、1.0%和2.0%的等氮等脂微颗粒饲料(游离谷氨酰胺测定值分别为0.03%、0.46%、0.91% 和1.73%), 饲喂35日龄半滑舌鳎稚鱼[平均干重(10.640.86) mg]。每天饱食投喂5次,养殖周期30d, 养殖结束后进行低氧应激实验。研究结果表明, 谷氨酰胺添加量为0.5%时半滑舌鳎稚鱼鱼体溶菌酶(LZM)活力显著高于未添加组(P0.05)。饲料中不同谷氨酰胺水平对鱼体总一氧化氮合酶(TNOS)活力和诱导型一氧化氮合酶(iNOS)活力没有显著影响(P0.05)。实验克隆了半滑舌鳎低氧应激关键基因缺氧诱导因子1 (HIF-1), 得到749 bp半滑舌鳎HIF-1核心序列, 系统进化树分析表明半滑舌鳎HIF-1氨基酸序列与大部分鱼类具有较高同源性。定量PCR结果显示, 饲料中谷氨酰胺水平对低氧应激后半滑舌鳎稚鱼内脏团HIF-1表达量未产生显著影响(P0.05)。综上所述, 在饲料中添加谷氨酰胺能够显著增强半滑舌鳎稚鱼鱼体溶菌酶活力(P0.05), 提高非特异性免疫水平。     

中草药饲料添加剂对真鲷(Pagrosomus major)幼鱼生长和非特异性免疫的影响

设计中草药配方分别以1%、2%、3%剂量分粉剂和汁剂的方式添加到基础饲料中,连续投喂真鲷幼鱼2个月。分三个阶段(每20天一阶段)测定鱼体的增重、饵料系数、血液中的NBT阳性细胞和血清中的溶菌酶的活力。结果表明,中草药添加剂能够极显著地影响真鲷幼鱼的生长、血液中NBT阳性细胞数和血清中的溶菌酶的活力(p＜0．01)。且两种添加方式均在第二、三阶段比对照组出现了极显著的差异,且均以2%的添加剂量效果为最佳。     

大黄素、维生素C及其配伍对团头鲂抗拥挤胁迫的影响

选取1200尾健康的团头鲂(Megalobrama amblycephala Yih),体重为(133.44±2.11)g,随机分成4组,其中1组为对照组,投喂基础日粮(含50.3 mg/kg维生素C,以L-抗坏血酸-2-多聚磷酸酯为Vc源),另外3组为试验组,投喂饲料是在基础日粮中分别添加60 mg/kg大黄素、700 mg/kg Vc、60 mg/kg大黄素+700 mg/kg Vc。饲养60d后,从各池中取25尾规格基本一致的鱼,进行连续48h的拥挤胁迫(100 g/L)实验,分别于0h、12h、24h、48h取样分析团头鲂血液和肝脏的生化指标以及肝脏两种HSP70s mRNA的表达水平,并统计各组鱼的累积死亡率。结果表明,在拥挤胁迫前,与对照组相比,大黄素、Vc组显著提高了团头鲂血清总蛋白(TP)、溶菌酶(LSZ)和碱性磷酸酶(AKP)的水平,肝脏超氧化物歧化酶(SOD)的活性和诱导型HSP70 mRNA的表达水平,降低了血清皮质醇(COR)、甘油三酯(TG)以及肝脏丙二醛(MDA)的含量(P<0.05),且大黄素组还显著提高了肝脏过氧化氢酶(CAT)的活性(P<0.05);配伍组虽然血清TP、LSZ以及肝脏HSP70 mRNA的水平显著升高,肝脏MDA的含量也显著降低(P<0.05),但均未表现出协同增效作用。在拥挤胁迫后,与对照组相比,大黄素、Vc组不同程度地提高了团头鲂血清TP和AKP的水平,肝脏SOD和CAT的活性以及HSC70和HSP70 mRNAs的表达水平,降低了血清COR、葡萄糖(GLU)、谷丙转氨酶(GPT)、谷草转氨酶(GOT)、TG以及肝脏MDA的水平,而LSZ活性表现为先下降后升高;在配伍组中,这些指标虽然有类似以上的变化趋势,但大多差异不显著(P>0.05),且同样未表现出协同增效作用。统计表明,大黄素和Vc组鱼的累积死亡率在拥挤胁迫24h、48h均显著低于对照组(P<0.05),而配伍组与对照组的差异均不显著(P>0.05)。由此可见,在基础日粮中添加大黄素60 mg/kg或Vc 700 mg/kg,可提高团头鲂的非特异性免疫力、抗氧化能力以及两种HSP70s mRNA的表达水平,增强鱼体的抗应激能力。二者配伍则效果不佳,其相互作用的机理还有待于进一步研究。     

淡水养殖太平洋鲑循环饥饿后补偿性生长效果研究

用16.1%脂肪,38.1%蛋白质含量日粮饲养108尾初始重约为240g的太平洋鲑(Oncorhynchusspp.)于0.25m3的水族箱中64d,水温为15.5±3.7℃。实验分6组,分别为对照组(每天投喂),实验1组(隔天投喂),实验2组(隔2天投喂2天),实验3组(隔4天投喂4天),实验4组(隔8天投喂8天),实验5组(隔16天投喂16天)。每组设3个平行水族箱,每箱6尾鱼。研究淡水养殖太平洋鲑多重周期饥饿后补偿性生长效果。实验结果表明:(1)各试验组太平洋鲑成活率均为100%。实验1、2、3组太平洋鲑鱼体增重接近对照组,其恢复摄食期间特定生长率、摄食率、食物转化率均显著或极显著高于对照组(P<0.05或0.01)。而实验4、5组鱼恢复摄食期间虽摄食率极显著高于对照组(P<0.01),但其鱼体增重、特定生长率、食物转化率均极显著低于对照组(P<0.01);(2)实验各组鱼肥满度、肝体比、肝脏脂肪和糖原含量、肌肉中脂肪含量较对照组均有不同程度下降,肝脏脂肪中总饱和脂肪酸比例上升,而总多不饱和脂肪酸比例下降;(3)实验1、2、3组血浆中甘油三酯、胆固醇和低密度脂蛋白显著低于对照组,而葡萄糖、血清中甲状腺激素T4浓度显著高于对照组(P<0.05)。实验结果表明,初重约240g太平洋鲑饥饿1—4d,再循环投喂相同时间64d后,获得了接近完全补偿生长效果,表现为其恢复摄食期间摄食率和食物转化率明显上升,生长速率明显加快,饲料报酬明显提高,鱼体增重接近持续喂食的对照组,养殖效益明显提高。但饥饿8—16d再循环投喂相同时间后,表现为无补偿生长效应,食物转化率和生长速率明显下降,鱼体增重极显著低于持续喂鱼的对照组。     

甘露寡糖对异育银鲫生长性能、免疫及HSP70基因表达的影响

为探讨甘露寡糖(MOS)对异育银鲫生长、免疫、肠道组织结构及抗病力的影响,试验选取360尾异育银鲫[初均重(16.19±0.03)g],随机分成5组、每组3个重复,在日粮中添加不同浓度甘露寡糖(0、60、120、240、480 mg/kg),连续投喂80d,并于第80天时进行嗜水气单胞菌感染,测定异育银鲫生长、免疫、肠道结构等指标及异育银鲫抗嗜水气单胞菌感染的能力。试验结果表明,无论投喂50d,还是80d,甘露寡糖对鱼体的生长指标(特定生长率、增重率、蛋白质效率、饵料系数)均没有显著影响(P>0.05);投喂50d,与对照组比,甘露寡糖能显著提高血清球蛋白浓度(P<0.05);投喂80d后,与对照组比,240、480 mg/kg甘露寡糖组能显著提高碱性磷酸酶活性,甘露寡糖组能显著提高血清球蛋白浓度(P<0.05),480 mg/kg甘露寡糖组能显著提高血清总抗氧化能力,120、240 mg/kg甘露寡糖组能显著提高肠褶皱襞长(P<0.05),对皱襞间质宽、黏膜下层宽没有显著影响(P>0.05),肌层宽随着MOS的添加有增加趋势(P>0.05);嗜水气单胞菌感染后,与对照组比,240、480 mg/kg甘露寡糖组成活率提高了22.6%,免疫保护率达45.4%。日粮中添加甘露寡糖组对鱼体肝脏HSP70基因表达没有显著影响(P>0.05)。因此,添加240、480 mg/kg甘露寡糖能提高鱼体的免疫能力,增强鱼体抗病原菌感染能力。     

无花果多糖对鲫鱼非特异性免疫功能的影响

实验研究了无花果多糖对鲫鱼非特异性免疫功能的影响。将鲫鱼分成A0、A1、A2、A3和A4五个组,其中A0组投喂基础饵料,设为对照组,而A1、A2、A3和A4分别投喂添加0.1%、0.2%、0.4%、0.8%无花果多糖的基础饵料,并在试验的第0、第7、第14、第21、第28、第35天检测鲫鱼血清补体C3含量、总蛋白含量、溶菌酶活力、SOD活性和血液白细胞吞噬活性。结果表明,A2组的补体C3含量、总蛋白含量、溶菌酶活力、SOD活性和血液白细胞吞噬活性显著高于A0组(P3组补体C3含量、SOD活性和血液白细胞吞噬活性极显著的高于A0组(P1组、A4组(P3组补体C3含量、总蛋白含量、溶菌酶活力、SOD活性和血液中白细胞吞噬活性与A2组相比差异不显著。A0组、A1组和A4组之间的补体C3含量、总蛋白含量、溶菌酶活力、SOD活性和血液白细胞吞噬活性无显著差异(P>0.05)。       

Influences of traditional Chinese medicine on non-specific immunity of Jian Carp (Cyprinus carpio var. Jian)

The influence of traditional Chinese medicine (TCM) formulation from Astragalus Root (Radix astragalin seu Hedysari) and Chinese Angelica Root (R. Angelicae Sinensis) at a ratio of 5:1 (w/w) on non-specific immunity of Jian carp, Cyprinus carpio var. Jian was investigated. The number of NBT-positive cells in the blood and lysozyme and complement activities in the serum of Carp fed with commercial feed supplemented with 1.0% (diet 1) and 1.5% (diet 2) TCM at 10 day of post-feeding were not different from those of the control group fed with feed unsupplemented TCM 10 days post-feeding (P>0.05), but at 20 and 30 days they increased significantly (P<0.05). The values of diet 1 group and diet 2 group at 20 day and at 30 day were not significantly different (P>0.05) from each other. In addition, the TCM formula increased body weight of experimental fish by about 16.84% (diet 1) and 19% (diet 2) above that of the control group. Therefore, these data suggest that the TCM formula could elevate the function of non-specific immunity of Jian carp. The optimal dosage added to commercial carp feed was 1.0% (w/w) and the oral administration time as a course of treatment was 20 days.     

高效降解蛋白枯草芽孢杆菌的筛选及促建鲤生长的研究

【目的】从建鲤肠道分离并优选出了一株对蛋白具有强效降解力的菌株,探究其临床生产效果。【方法】使用牛奶平板进行筛选,经常规细菌学鉴定和16S rDNA序列分析确定A7菌株为枯草芽孢杆菌,通过临床饲喂试验探究其对建鲤促生长作用。【结果】A7菌株在牛奶平板上的水解圈直径可达27.5 mm,其最佳固体发酵条件为温度28°C、接种量5%(1.2×109 CFU/mL)、料水比1.0:1.2和发酵时间72 h。临床饲喂试验结果表明,饵料中添加0.5%、1.0%和1.5%的A7株菌粉均能促建鲤生长。其中,添加量为1.0%的试验组,鱼体增重率和蛋白利用率最高,饵料系数最低,与产品对照组和空白对照组相比,均达到了显著性差异(P0.05)。此外,随A7株菌粉添菌量的增加,各试验组肝胰脏和肠道的蛋白酶及淀粉酶活力出现先增大后减小趋势,与产品对照组和空白对照组相比,添加1.0%的试验组增幅最大(P0.05)。研究发现,试验组鱼肌肉中粗蛋白和粗脂肪含量较空白对照组也有明显的增减趋势(P0.05)。【结论】饵料中添加A7株菌粉,可有效促进鱼的生长,降低饵料系数,提高肝胰脏和肠道的蛋白酶及淀粉酶活力,并提高鱼肌肉中的蛋白含量和降低脂肪含量。     

建鲤和异育银鲫摄食不同质量饲料时的氮收支和能量收支比较

实验探讨了建鲤和异育银鲫摄食低质和高质饲料时氮和能量的收支情况.低质饲料以豆粕为主要蛋白源,饲料蛋白含量为33.91%,高质饲料以鱼粉为主要蛋白源,饲料蛋白含量为45.59%.55d的生长结果显示,氮收支和能量收支受到饲料质量和鱼类种类的显著影响:摄食低质饲料时,建鲤的生长氮和生长能比例显著低于异育银鲫,排泄氮、排泄能和代谢能比例显著高于异育银鲫;摄食高质饲料时,两种鱼的氮收支和能量收支无显著差异;建鲤的氮收支和能量收支受饲料质量的显著影响,摄食低质饲料时,其生长氮和生长能比例均显著低于摄食高质饲料时,而排泄氮、粪能和代谢能比例均显著高于摄食高质饲料时;异育银鲫的氮收支、生长能和代谢能比例不受饲料质量的显著影响.结果表明,在低质饲料条件下,建鲤利用氮和能量的能力弱于异育银鲫,在高质饲料条件下,两种鱼没有显著差异.与异育银鲫相比,建鲤利用氮和能量的能力受饲料质量的影响更为显著.       

Coriolus versicolor polysaccharides enhance the immune response of crucian carp (Corassius auratus gibelio) and protect against Aeromonas hydrophila

To investigate the effect of Coriolus versicolor polysaccharides (CVPS) on the immune response of crucian carp (Corassius auratus gibelio), fish were fed diets containing CVPS at different concentrations including 0.5, 1.0 and 2.0 g kg^?1 for 5 weeks. Other groups of fish were vaccinated by intraperitoneal injection (i.p.) against Aeromonas hydrophila with a killed bacterin at the beginning of the experiment and fed the same diets as described above. Additionally, control fish and vaccinated‐only fish were fed basal diets without CVPS supplementation. The phagocytosis, lysozyme activity, complement components C3 and C4, E‐C3bRR (Erythrocyte‐C3b rosette rate) and E‐CIRR (Erythrocyte‐immune complex rosette rate) levels and circulating antibody titers in the serum were monitored. Five weeks after feeding the prescribed diet, fish were challenged with A. hydrophila and the mortalities recorded. Results showed that feeding non‐vaccinated and vaccinated crucian carp with CVPS stimulated the phagocytosis of leukocytes, lysozyme, complement components C3 and C4, erythrocyte immune adherence, and circulatory antibody titers in serum in vaccinated crucian carp. Immune parameters increased to their highest levels after 3 weeks of feeding the diet containing 0.5 or 1.0 g kg^?1 CVPS. These doses also resulted in the highest protection in the challenge experiment. Best survival (85%) was in the vaccinated group fed the diet containing 1.0 g kg^?1 CVPS, whereas almost 80% of control fish (negative control) and 50% of vaccinated‐only fish (positive control) died.     

Effects of polyherbal formulation 'ImmuPlus' on immunity and disease resistance of Indian major carp, Labeo rohita at different stages of growth

A series of experiments were performed to determine the impact of polyherbal immunomodulatory formulation 'ImmuPlus' (AquaImmu) on growth, immunity and disease resistance of rohu (Labeo rohita), one of the Indian major carp at different stages of growth. Rohu larvae were fed on plankton, ImmuPlus-mixed compound feed, and plankton plus ImmuPlus-mixed compound feed (ImmuPlus added at three dose levels of 0.25, 0.50, and 0.75 g/kg feed) from 4th day of hatching to 14th day. ImmuPlus-mixed diets enhanced growth of larvae, survival and disease resistance against Aeromonas hydrophila challenge, compared to only plankton-fed group. In two other experiments, advanced rohu larvae and fingerlings were fed with ImmuPlus-mixed compound feed (at 0, 0.5, 1.0 and 2.0 g/kg) for 15, 30 and 45 days. At the end of 45 days for advanced larvae and 30 days for fingerlings, the fish fed with ImmuPlus at 1.0 g/kg level showed significantly higher growth and disease resistance against A. hydrophila challenge. In a separate experiment, juveniles of rohu were fed with 1 g/kg of ImmuPlus incorporated feed for 15 and 30 days. At the end of the trial, the ImmuPlus fed fish showed enhanced non-specific immunity (as measured through nitroblue tetrazolium reduction assay, serum lysozyme activity, serum haemolysin titre and resistance against A. hydrophila challenge in non-vaccinated fish as well as specific immunity levels (as measured through bacterial agglutination titre against A. hydrophila in vaccinated fish). Incorporation of ImmuPlus at 1 g/kg level in the diet of rohu may be beneficial for enhancing disease resistance.     

Effects of dietary chitosan and Bacillus subtilis on the growth performance, non-specific immunity and disease resistance of cobia, Rachycentron canadum

The present study was performed to investigate the effects of various levels of dietary Bacillus subtilis and chitosan on the growth performance, non-specific immunity and protection against Vibrio harveyi infection in cobia, Rachycentron canadum. Fish were fed with the control diet and six different experimental diets containing three graded levels of B. subtilis at 2 × 10(10) CFU g(-1) (0.0, 1.0, 2.0 g kg(-1) diet) for each of two levels of chitosan (3.0 and 6.0 g kg(-1) diet). The results of 8 weeks feeding trial showed that the survival rate ranged from 81.3% to 84.0% with no significant difference (P > 0.05). The SGR (%) in the fish fed with dietary treatments was significantly higher than that of the control fish except diet 6 group with 2.0 g kg(-1)B. subtilis and 3.0 g kg(-1) chitosan. The serum lysozyme activities were significantly higher in 6.0 g kg(-1) chitosan groups and no significant differences were observed among B. subtilis levels. The serum ACP activities were significantly higher in 3.0 g kg(-1) chitosan groups at 0.0 and 1.0 g kg(-1)B. subtilis levels; at low chitosan level, the cobia fed diets with 1.0 g kg(-1)B. subtilis had significantly higher serum ACP activity, but at high chitosan level, the cobia fed diets with 2.0 g kg(-1)B. subtilis had significantly higher serum ACP activity. The phagocytosis and respiratory burst activity in the fish fed with dietary treatments was significantly higher than that of the control fish except diet 3 group with 6.0 g kg(-1) chitosan. Moreover, fish fed the diet containing 2.0 g kg(-1)B. subtilis and 6.0 g kg(-1) chitosan had significantly higher post-challenge survival on the 7th day following V. harveyi infection and post-challenge survival showed clearly the synergistic effect of chitosan and B. subtilis. Based on these results, the combination of 1.0 g kg(-1)B. subtilis and 6.0 g kg(-1) chitosan is optimal for the growth, innate immunity and disease resistance of cobia with an 8-week oral administration.     

Effects of anthraquinone extract from Rheum officinale Bail on the physiological responses and HSP70 gene expression of Megalobrama amblycephala under Aeromonas hydrophila infection

We evaluated the effect of dietary supplementation with anthraquinone extract (from Rheum officinale Bail) on the resistance to Aeromonas hydrophila infection in Megalobrama amblycephala. The fish were randomly divided into two groups: a control group (fed a standard diet) and a treatment group (standard diet supplemented with 0.1% anthraquinone extract) and fed for 10 weeks. We then challenged the fish with A. hydrophila and recorded mortality and changes in serum cortisol, lysozyme, alkaline phosphatase (ALP), total protein, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and hepatic catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA) and the relative expression of heat shock protein 70 (HSP70) mRNA for a period of 5 d. Supplementation with 0.1% anthraquinone extract significantly increased serum lysozyme activity before infection, serum ALP activity at 24 h after infection, serum total protein concentration 12 h after infection, hepatic CAT activity 12 h after infection, hepatic SOD activity before infection, and the relative expression of hepatic HSP70 mRNA both before infection and 6 h after infection. In addition, the supplemented group had decreased levels of serum cortisol 6 h after infection, serum AST and ALT activities 12 h after infection, and hepatic MDA content 12 h after infection. Mortality was significantly lower in the treatment group (86.67%) than the control (100%). Our results suggest that ingestion of a basal diet supplemented with 0.1% anthraquinone extract from R. officinale Bail can enhance resistance against pathogenic infections in M. amblycephala.     

Effects of graded levels of dietary methionine hydroxy analogue on immune response and antioxidant status of immune organs in juvenile Jian carp (Cyprinus carpio var. Jian)

Immune response and antioxidant status of immune organs in juvenile Jian carp (Cyprinus carpio var. Jian) fed graded levels of methionine hydroxy analogue (MHA) (0, 5.1, 7.6, 10.2, 12.7, 15.3 g kg(-1) diet) for 60 days were investigated. Results indicated that head kidney index, spleen index, red and white blood cell counts significantly increased with increasing MHA levels up to a point (P < 0.05), whereupon decreased (P < 0.05). Glutathione reductase activity in head kidney and spleen, anti-hydroxy radical and glutathione-S-transferase activities in spleen, catalase activity and GSH content in head kidney significantly increased by MHA supplement, while malondialdehyde content, anti-superoxide anion, superoxide dismutase, glutathione peroxidase activities in head kidney and spleen, protein carbonyl content and catalase activity in spleen, anti-hydroxy radical activity in head kidney significantly decreased by MHA supplement. However, protein carbonyl content and glutathione-S-transferase activity in head kidney, GSH content in spleen remained unaffected. After 60-day feeding trial, a challenge study was conducted by injection of Aeromonas hydrophila for 17 days. Results showed that survival rate, leukocytes phagocytic activity, lysozyme activity, acid phosphatase activity, total iron-binding capacity, haemagglutination titre, complement 3, 4 and immunoglobulin M contents significantly increased by optimal dietary MHA supplement (P < 0.05). These data suggested that MHA affected antioxidant status of immune organs and promoted immune response in juvenile Jian carp.