大黄蒽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,应激前添加大黄蒽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,但是与大黄蒽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。     

饲料中添加壳聚糖和益生菌对暗纹东方纯幼鱼生长及部分消化酶活性的影响

在基础饲料中分别添加不同浓度的益生菌(0.1%、0.2%、0.4%)、壳聚糖(0.2%、0.5%、1.0%)、壳聚糖与益生菌混合物、甘露聚糖与益生菌混合物,在室内水泥池(5.0m×2.0m×1.0m)中喂养暗纹东方鲀幼鱼(3.15±0.05g),用基础饲料投喂暗纹东方鲀作为对照,每组三个重复,60d后测定鱼体的生长、肌肉生化成分、肝胰脏、肠道蛋白酶和淀粉酶活性和白肌RNA/DNA。结果显示,对照组相对增重率为476.4%,饲料中添加0.2%的壳聚糖、0.1%的益生菌对暗纹东方鲀的促生长作用最明显,相对增重率显著提高。壳聚糖与益生菌混合物、甘露聚糖与益生菌混合物对生长无显著影响。对照组肌肉蛋白质和脂肪含量分别为82.94%、11.21%,壳聚糖、益生菌与甘露聚糖在饲料中的添加,能够显著降低肌肉脂肪含量,显著提高肌肉蛋白质含量,也能在一定程度上降低肝体比。0.2%壳聚糖和0.1%益生菌能使肠道淀粉酶活性显著增强(P<0.05),白肌RNA/DNA显著增大(P<0.05),说明肠道淀粉酶活性增强和蛋白质合成增加是壳聚糖和益生菌促进暗纹东方鲀生长的重要原因。     

三丁酸甘油酯对异育银鲫生长性能及免疫功能的影响

为研究三丁酸甘油酯(tributyrin, TB)对异育银鲫生长和免疫的影响,以基础饲料作为对照,分别在基础饲料中添加0.5 g/kg、1 g/kg、1.5 g/kg、2 g/kg TB配制成4种实验饲料。实验选择健康、体重相近(43.58±1.6) g的异育银鲫450尾,随机分为5组,每组3个重复,每个重复30尾。预试期2周,正试期8周,实验结束后检测其生长性能和免疫指标。结果表明:各实验组异育银鲫的增重率、特定生长率与对照组相比都得到提高,其中添加1 g/kg TB效果最佳,显著降低了饵料系数(p0.05)。各实验组的头肾和脾脏指数在添加量为0.5～1.0 g/kg范围内显著高于对照组(p0.05)。各实验组的肝胰脏中一氧化氮含量均低于对照组、过氧化氢酶含量均高于对照组,且除2 g/kg TB外其他实验组均差异显著(p0.05);肝胰脏中超氧化物歧化酶活性在添加量为1 g/kg和1.5 g/kg显著高于对照组(p0.05),超过2 g/kg时则会抑制其活性,但差异不显著(p0.05);各实验组的肝胰脏中丙二醛和溶菌酶的含量均低于对照组,且在添加量为1 g/kg TB时差异显著(p0.05)。综合来看,添加适量的TB能提高异育银鲫的生长性能,增强其免疫能力,当添加量为1.02 g/kg时效果最佳。     

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。     

草鱼高脂日粮磷酸二氢钙适宜添加量的研究

为探讨草鱼高脂(7%)实用日粮磷酸二氢钙(MCP)适宜添加量对草鱼生长性能、脂质代谢及抗氧化能力的影响, 以磷酸二氢钙[Ca (H₂PO₄)]为磷源, 配制含MCP分别为0(对照组)、1.0%、2.0%、3.0%和4.0%的5种等氮等能实用日粮, 饲喂初始均重为(105.23±0.55) g的试验草鱼, 每种日粮设置3个重复, 每个重复15尾鱼, 进行为期8周的养殖试验。结果显示: 在高脂日粮中添加适宜的MCP可显著增加草鱼增重率(WGR)和全鱼磷含量, 降低饲料系数(FCR)和脏体比(VSI)。以WGR、FCR和全鱼磷为观测指标, 折线模型分析得出日粮MCP适宜添加量分别为3.26%、2.96%和2.63%; 全鱼、内脏、肌肉和肝脏粗脂肪含量随日粮中MCP的增加呈先降后升趋势, 而全鱼和肌肉粗蛋白含量则呈相反趋势; 在MCP3.0%组, 草鱼肠道淀粉酶、脂肪酶、胰蛋白酶活性, 血清碱性磷酸酶(AKP)活性最高, 血清甘油三酯、肝脏丙二醛含量, 乙酰辅酶A羧化酶(ACC)活性最低; 添加组血清总胆固醇含量均显著低于对照组(P<0.05), 肝脏肉碱脂酰转移酶(CPT-I)活性随日粮MCP添加量增加而渐增。研究表明, 草鱼高脂(7%)日粮中MCP适宜添加水平为2.96%—3.26% (饲料总磷1.43%—1.50%), 该添加水平能促进草鱼对日粮中营养物质的消化利用, 减少鱼体及肝脂蓄积, 增加鱼体蛋白, 提高抗氧化机能, 促进生长。     

壳聚糖对香鱼溶菌酶活性和hsp70基因表达的影响

壳聚糖是一种理想的水产动物免疫增强剂和饲料添加剂。为了研究壳聚糖对香鱼非特异性免疫机能的影响,探讨其调节机体免疫功能的机理,以香鱼为研究对象,在基础饲料中分别添加0%、0.5%、1.0%、2.0%和4.0%的壳聚糖,连续投喂35 d后测定香鱼肝脏、脾脏和肾脏组织中溶菌酶活性和免疫相关基因hsp70基因表达的影响。结果表明,基础饲料中添加1.0%壳聚糖可使香鱼肝脏、脾脏和肾脏组织中溶菌酶活性显著提高,溶菌酶活性与对照分别提高了0.8倍、3.1倍和5.2倍。定量PCR分析结果表明,添加1.0%壳聚糖可显著促进肝脏、脾脏和肾脏中hsp70基因的表达量,且hsp70基因表达量与溶菌酶活性表现出一定的相关性,表明壳聚糖可通过调节免疫相关基因的表达来调节香鱼的免疫功能。     

人参茎叶提取物对刺参生长、免疫及抗病力的影响

以初始体重为(4.910.17) g的刺参(Apostichopus japonicas)为研究对象,研究投喂不同剂量人参茎叶提取物对刺参生长、免疫及抗病力的影响,探讨人参茎叶提取物在刺参养殖中的应用。在每千克基础饲料中分别添加10、20、40和80 g人参茎叶提取物作为实验组,并以基础饲料为对照进行为期30d的饲喂养殖。结果显示,投喂人参茎叶提取物对刺参的生长并无显著影响,刺参特定生长率不随人参茎叶提取物添加量的增加而提高。当人参茎叶提取物添加量为80 g/kg时,刺参体腔细胞总数、呼吸暴发强度、细胞吞噬活性、超氧化物歧化酶活力、总一氧化氮合酶活力均显著高于对照组(P0.05);当人参茎叶提取物添加量为40 g/kg时,细胞吞噬活性也显著高于对照组(P0.05),但其余免疫指标与对照组相比无显著差异(P0.05);当人参茎叶提取物的添加量不大于20 g/kg时,各项免疫指标与对照组之间均无显著差异(P0.05)。攻毒实验表明, 20、40和80 g/kg人参茎叶提取物组的健康率要高于对照组,其中80 g/kg人参茎叶提取物组健康率为80.56%要显著高于对照组和10 g/kg人参茎叶提取物组(P0.05)。人参茎叶提取物可作为免疫增强剂应用于刺参的养殖中来提高刺参的免疫和抗病能力。       

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。     

菊粉和刺五加提取物对早期断奶仔猪生长性能、血液指标和肠道形态的影响

试验选用120头21日龄5.64kg左右的三元杂交断奶仔猪,分别饲喂基础日粮(对照组)、基础日粮+抗生素(抗生素组)和基础日粮+5%菊粉+0.1%刺五加提取物(实验组),试验期为14d,观察日粮中复合添加菊粉和刺五加(AS)提取物对早期断奶仔猪生长性能、血液生化指标和肠道形态的影响。试验结果表明,实验组与对照组相比,仔猪日增重(ADG)显著提高(P0.05),而料肉比(F/G)则显著降低(P0.05),但平均日采食量(ADFI)差异不显著(P0.05);实验组仔猪血清中血糖(GLU)、低密度脂蛋白(LDL)、乳酸脱氢酶(LDH)和尿素氮(BUN)与对照组差异不显著(P0.05),但试验第14d,碱性磷酸酶(ALP)、超氧化物歧化酶(SOD)和还原型谷胱甘肽(GSH)浓度均显著高于对照组(P0.05);实验组仔猪十二指肠和回肠的隐窝深度显著高于对照组(P0.05),空肠和回肠的绒毛高度显著高于对照组(P0.05)。试验显示,日粮中添加菊粉和刺五加提取物对提高早期断奶仔猪的生长性能、改善小肠消化和吸收功能有重要作用。     

Immunomodulatory effect of sodium alginate enriched diet in kelp grouper Epinephelus brneus against Streptococcus iniae

The effect of diets containing sodium alginate at 0, 0.5, 1.0, and 2.0 g kg^?1 following challenge with Streptococcus iniae in kelp grouper Epinephelus bruneus were assessed with reference to survival rate and innate immune parameters such as alternative complement, lysozyme, natural haemagglutination, respiratory burst, superoxide dismutase, and phagocytic activities on week 1, 2, and 4. Fish fed with sodium alginate containing diet at 1.0 and 2.0 g kg^?1 after being challenged with S. iniae had higher survival rates of 75% and 60%, respectively than those fed with control diet (0 g kg^?1). With any enriched diet the percentage of macrophages significantly decreased from week 1–4, while the percentage of neutrophils and lymphocytes significantly increased. The alternate complement activity, natural haemagglutination, and phagocytic activities of infected fish fed with sodium alginate containing diet at 1.0 g kg^?1 on week 2 and 1.0 and 2.0 g kg^?1 diets on week 4 were significantly higher when compared to the control. The lysozyme, respiratory bursts, and superoxide dismutase activities of fish fed with enriched diets at 1.0 and 2.0 g kg^?1 were significantly increased on week 2 and 4. We therefore recommend that at 1.0 or 2.0 g kg^?1 dietary administration of sodium alginate can enhance innate immunity and disease resistance in kelp grouper against S. iniae.     

Dietary sodium alginate administration affects fingerling growth and resistance to Streptococcus sp. and iridovirus, and juvenile non-specific immune responses of the orange-spotted grouper, Epinephelus coioides

The percent weight gain (PWG) and feeding efficiency (FE) of fingerling orange-spotted grouper, Epinephelus coioides, fed diets containing sodium alginate at 1.0 and 2.0 g kg(-1) were calculated on the 2nd, 4th, 6th, and 8th weeks after feeding. Survival rates of the fingerling grouper against Streptococcus sp. and an iridovirus, and non-specific immune parameters such as alternative complement activity (ACH50), lysozyme activity, natural haemagglutination activity, respiratory bursts, superoxide dismutase (SOD) activity, and phagocytic activity of juvenile grouper were also determined when the fish were fed diets containing sodium alginate at 0.5, 1.0, or 2.0 g kg(-1). The PWG and FE of fish were better when the fish were fed diets containing sodium alginate at 1.0, and 1.0 and 2.0 g kg(-1), respectively. The PWG and FE of fish fed the 0, 1.0 and 2.0 g kg(-1) sodium alginate-containing diets after 8 weeks were 271.0%, 454.4% and 327.8%, and 0.61, 0.72 and 0.68, respectively. Fish fed a diet containing sodium alginate at the level of 2.0 g kg(-1) had a significantly higher survival rate than those fed the control diet after challenge with Streptococcus sp. and an iridovirus causing an increase of survival rate by 25.0% and 16.7%, respectively, compared to the control group. The ACH(50) level of fish fed the sodium alginate-containing diets at 2.0 g kg(-1) was significantly higher than those fed the 1.0 g kg(-1) sodium alginate diet and control diet after 12 days, and had increased to 1.9-fold, compared to those fed the control diet. The lysozyme activity, phagocytic activity, respiratory bursts, and SOD level of fish fed the sodium alginate-containing diets at 1.0 and 2.0 g kg(-1) were significantly higher than those fed the control diet after 12 days, and had increased to 1.97- and 1.68-fold, 1.35- and 1.50-fold, 1.63- and 1.81-fold, and 1.23- and 1.31-fold, respectively, compared to those fed the control diet. We therefore recommend dietary sodium alginate administration at 1.0 and 2.0 g kg(-1), respectively, to promote growth and enhance immunity and resistance against Streptococcus sp. and an iridovirus.     

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.     

Dietary administration of a Gracilaria tenuistipitata extract enhances the immune response and resistance against Vibrio alginolyticus and white spot syndrome virus in the white shrimp Litopenaeus vannamei

The haemogram, phenoloxidase (PO) activity, respiratory bursts (RBs), superoxide dismutase (SOD) activity, glutathione peroxidase (GPx) activity, lysozyme activity, and the mitotic index of haematopoietic tissue (HPT) were examined after the white shrimp Litopenaeus vannamei had been fed diets containing the hot-water extract of Gracilaria tenuistipitata at 0 (control), 0.5, 1.0, and 2.0 g kg(-1) for 7-35 days. Results indicated that these parameters directly increased with the amount of extract and time, but slightly decreased after 35 days. RBs, SOD activity, and GPx activity reached the highest levels after 14 days, whereas PO and lysozyme activities reached the highest levels after 28 days. In a separate experiment, white shrimp L. vannamei, which had been fed diets containing the extract for 14 days, were challenged with Vibrio alginolyticus at 2 × 10(6) cfu shrimp(-1) and white spot syndrome virus (WSSV) at 1 × 10(3) copies shrimp(-1), and then placed in seawater. The survival rate of shrimp fed the extract-containing diets was significantly higher than that of shrimp fed the control diet at 72-144 h post-challenge. We concluded that dietary administration of the G. tenuistipitata extract at ≤1.0 g kg(-1) could enhance the innate immunity within 14 days as evidenced by the increases in immune parameters and mitotic index of HPT in shrimp and their enhanced resistance against V. alginolyticus and WSSV infections. Shrimp fed the extract-containing diets showed a higher and continuous increase in the humoral response indicating its persistent role in innate immunity.     

Enhancement of Eriobotrya japonica extracts on non-specific immune response and disease resistance in kelp grouper Epinephelus bruneus against Vibrio carchariae

The present study investigated the effect of Eriobotrya japonica extracts at 0%, 0.1%, 1.0%, and 2.0% doses supplementation with feed on non-specific immune response, hematological and biochemical profile, and disease resistance against Vibrio carchariae in kelp grouper Epinephelus bruneus at weeks 1, 2, and 4. The white blood cell (WBC) significantly increased in fish fed with 0.1%, 1.0%, and 2.0% diets on weeks 1 and 2 when compared to the control. However, the glucose always decreased from the control except on week 2 against pathogen. The serum total protein, albumin, and globulin significantly increased at week 2 but they did not changed significantly at weeks 1 and 4. The superoxide anion, lymphokines production index, and phogocytosis did not significantly increased in any diet on the first week whereas it was significantly enhanced in 1.0% and 2.0% supplementation diets on weeks 2 and 4 against V. carchariae when compared to control. All diets significantly enhanced the serum lysozyme activity, bactericidal activity, and haemolytic complement activity from weeks 1-4 as compared to control. The serum agglutinating antibody titre did not significantly enhance on the first week whereas it was significantly enhanced on weeks 2 and 4. Fish fed with 1.0% and 2.0% doses diets was found lower mortality than 0.1% diet. Thus, this study suggested that 1.0% and 2.0% doses supplementation diets could be advocated to enhance the immune response and production disease from V. carchariae in E. bruneus.     

Inonotus obliquus containing diet enhances the innate immune mechanism and disease resistance in olive flounder Paralichythys olivaceus against Uronema marinum

The present study describes the effect of diet supplementation with Chaga mushroom, Inonotus obliquus extract at 0%, 0.01%, 0.1%, and 1.0% levels on the innate humoral (lysozyme, antiprotease, and complement), cellular responses (production of reactive oxygen and nitrogen species and myeloperoxidase), and disease resistance in olive flounder, Paralichythys olivaceus against Uronema marinum. The lysozyme activity and complement activity significantly increased in each diet on weeks 2 and 4 against pathogen. The serum antiprotease activity and reactive nitrogen intermediates production significantly increased in fish fed with 0.1% and 1.0% diets from weeks 1-4. However, reactive oxygen species production and myeloperoxidase activity significantly increased in 1.0% and 2.0% diets on weeks 2 and 4. In fish fed with 0.1% and 1.0% diets and challenged with U. marinum the cumulative mortality was 50% and 40% while in 0% and 0.01% diets the mortality was 85% and 55%. The results clearly indicate that supplementation diet with I. obliquus at 0.1% and 1.0% level positively enhance the immune system and confer disease resistance which may be potentially used as an immunoprophylactic in finfish culture.     

Immunostimulatory response induced by supplementation of Ficus benghalensis root powder, in the artificial feed the Indian freshwater murrel, Channa punctatus

Methanol extract from the dried aerial root of Ficus benghalensis, was used to evaluate antibacterial activity on the bacterial strains of Aeromonas hydrophila and Escherichia coli, by disc diffusion method. In order to study, if there is any immunostimulatory response of F. benghalensis, immunized fish were fed with supplementary artificial feed containing 5% F.?benghalensis dried root powder. There was no marked difference in the levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in control and treated fish, suggesting that the supplementary feed had no adverse effect on liver or kidney. Serum lysozyme, tissue super oxide dismutase (SOD), percentage phagocytosis, phagocytotic index, nitric oxide (NO), total serum protein and immunoglobulin increased significantly in the treated fish compared to control fish. Serum immunoglobulin levels were estimated by development of a sandwich ELISA, and levels were found to increase with successive immunizations of BSA.     

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。