亚硝态氮慢性胁迫对凡纳滨对虾体成分和糖代谢的影响

为研究亚硝态氮(NO2–-N)慢性胁迫对凡纳滨对虾(Litopenaeus vannamei)[(2.03±0.33) g]生长、摄食、体成分和糖代谢的影响,实验设置0 (对照组)、8 (N8组)、15 (N15组)和30 mg/L (N30组) NO2–-N浓度组,进行36 d的NO2–-N慢性胁迫实验。结果显示,随着NO2–-N浓度升高,对虾的终末体重、特定生长率、增重率和日摄食率均呈显著下降趋势。N8组和N15组对虾的血糖和肝胰腺中糖原含量在实验中期高于对照组,但最终均低于对照组,而肌肉中糖原含量在实验期间始终低于对照组。胁迫组凡纳滨对虾肌肉中的己糖激酶活力低于对照组;而肝胰腺己糖激酶活力和丙酮酸激酶活力均高于对照组,同时,肝胰腺乳酸含量与乳酸脱氢酶活力呈先上升后下降的趋势,最终与对照组相比无显著差异。终末体成分中,N30组的粗脂肪含量显著低于对照组。结果表明,NO2–-N慢性胁迫会降低对虾食欲,减缓凡纳滨对虾的生长,机体糖代谢调节可作为对虾应对NO2–-N慢性胁迫的短期响应,对虾对脂质的利用在应对NO2–-N慢性胁迫过程中起重要作用。     

亚硝态氮对中华鳑鲏的急性毒性及短期影响

静水试验条件下研究了亚硝态氮对体质量(0.636±0.09) g的中华鳑鲏急性毒性及短期胁迫下对其体内两种酶活性的影响。在水温25℃、溶解氧6.3 mg/L、pH 7.4时,测定亚硝态氮对中华鳑鲏的24 h半致死质量浓度,并设置高、中、低3个亚硝态氮质量浓度组[1.28、0.64、0.43 mg/L(1/10×24 h半致死质量浓度、1/20×24 h半致死质量浓度、1/30×24 h半致死质量浓度)],于0、24、48、72 h采集血样,测定血清中过氧化氢酶和碱性磷酸酶的活性。试验结果表明,亚硝态氮对中华鳑鲏的24 h半致死质量浓度为12.76 mg/L。在亚硝态氮胁迫作用下,中华鳑鲏血清中过氧化氢酶活性先显著上升,48 h后开始下降;碱性磷酸酶活性变化则是先显著下降,在48 h恢复,然后再下降。碱性磷酸酶活性在24 h和72 h均受到明显抑制。亚硝态氮质量浓度和暴露时间两者之间存在显著交互作用,碱性磷酸酶可以作为亚硝态氮毒性检测的生物标记物。     

亚硝态氮胁迫对日本蟳免疫指标的影响

15℃下将体质量(85.51±16.18)g的日本蟳暴露于对照及低质量浓度(2.0、4.0mg/L)、中质量浓度(6.0mg/L)和高质量浓度(8.0、10.0mg/L)的亚硝态氮中,于胁迫的第1、3、5、10、15d取血,测定其免疫的相关指标,以研究亚硝态氮质量浓度对日本蟳免疫功能的影响。试验结果表明,在亚硝态氮胁迫下,所测指标均呈"先升后降"的趋势。在胁迫第1d,各试验组的血细胞密度、血蓝蛋白含量及溶菌酶、超氧化物歧化酶、过氧化氢酶活力均大于对照组,而高质量浓度组的酚氧化酶活力低于对照组。随着亚硝态氮胁迫时间的延长,低质量浓度组血细胞密度和溶菌酶活力上升较快,而高质量浓度组酚氧化酶、超氧化物歧化酶和过氧化氢酶活力上升较快。低质量浓度组的血细胞密度和过氧化氢酶活力升高幅度较大,高质量浓度组的血蓝蛋白含量及酚氧化酶、溶菌酶、超氧化物歧化酶活力升高幅度较大。胁迫第10d,各试验组溶菌酶、超氧化物歧化酶和过氧化氢酶活力显著低于对照组(P<0.05)。胁迫第15d,低质量浓度组血细胞密度、2.0mg/L组的血蓝蛋白含量、低质量浓度组和中质量浓度组的酚氧化酶活力略大于对照组,其他各指标所测结果均低于对照组。各试验组溶菌酶、超氧化物歧化酶和过氧化氢酶胁迫后活力与亚硝态氮胁迫质量浓度呈负相关,10.0mg/L组的3种酶活力分别比对照组降低95.41%、36.84%和77.78%。     

亚硝态氮胁迫对草鱼非特异性免疫性能的影响

为探讨亚硝态氮胁迫对草鱼(Ctenopharyngodon idellus)非特异性免疫性能的影响,将草鱼(0.15±0.05 g)分别暴露在0 mg/L、0.2 mg/L、0.4 mg/L、0.8 mg/L、1.0 mg/L、2.0 mg/L、4.0 mg/L和8.0 mg/L的亚硝态氮溶液中,分别在暴露后0 d、1 d、4 d、7 d测定草鱼体内补体C3和C4含量、超氧化物歧化酶(SOD)活力、谷胱甘肽(GSH)含量以及γ-谷氨酰半胱氨酸合成酶(γ-GCS)活性。结果表明,亚硝态氮胁迫对草鱼非特异性免疫性能产生了消极影响,其胁迫效应随着暴露浓度的不同而表现出不同的特性。当暴露浓度低于1.0 mg/L时,补体C3和C4含量维持正常水平或显著升高;但暴露浓度超过1.0 mg/L,补体C3和C4含量水平会显著下降。SOD活性随着暴露时间而显著升高,但高浓度暴露使SOD活性在暴露7 d时显著下降。γ-GCS活性一般都随着暴露时间延长而显著升高,虽然暴露后期其活性下降,但还是显著高于对照组。而GSH含量在暴露4 d时显著升高,低浓度组(<1.0 mg/L)在7 d时恢复至对照水平。     

亚硝态氮胁迫对斑节对虾(非洲群体)氧化应激、能量代谢和渗透调节的影响

为研究亚硝态氮(NO₂-N)对斑节对虾(非洲群体)氧化应激、能量代谢和渗透平衡的影响,实验选取体长(3.0±0.5) cm的斑节对虾,设置0 (对照组)、5、10和15 mg/L(3个胁迫组)的亚硝态氮浓度梯度,进行了为期72 h的急性胁迫。实验结果显示,肝胰腺氧化应激因子活性(或含量)随着胁迫时间发展而变化。超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、过氧化氢酶(CAT)以及一氧化氮合酶(NOS)活性先升高后下降,24 h,SOD和GSH-Px、NOS活性达到最大值,10 mg/L胁迫组的SOD、GSH-Px活性和15 mg/L胁迫组的NOS活性显著高于其他3组;丙二醛(MDA)含量变化相反,24 h胁迫组的MDA含量最小,其中10 mg/L胁迫组显著低于其他3组;48 h,CAT活性达到最大值,10 mg/L胁迫组显著高于其他3组;一氧化氮(NO)含量随着胁迫时间的延长而逐渐升高,72 h,NO含量最高,15 mg/L胁迫组显著高于其他3组。血清能量代谢指标中脂肪酶(LPS)活性先上升后下降,48 h,LPS活性达到最大值,其中10 mg/L...     

一株去除亚硝态氮细菌分离鉴定及特性研究

自对虾养殖后期池水中分离纯化出一株高效去除亚硝态氮的细菌,进行了菌体的亚显微形态观察和16SrDNA同源序列分析,并探讨了起始pH、温度和碳氮比对该菌株去除亚硝态氮效果的影响。结果表明,分离菌株在初始亚硝态氮质量浓度为55.51mg/L的异养硝化培养基中培养12h后,亚硝态氮去除率达到98.69%;根据形态学特征、生理生化特性及16SrDNA序列分析,确定该菌株为脱氮海洋单胞菌,菌株去除亚硝态氮的最适宜条件为:初始pH 9,温度35℃,碳氮比16。     

非离子氨胁迫对淡水和海水养殖凡纳滨对虾呼吸代谢酶活力影响的比较

为了探讨非离子氨胁迫对淡水和海水两种养殖条件的凡纳滨对虾呼吸代谢酶活力的影响,在实验室条件下研究了非离子氨胁迫(0.1 mg/L和0.5 mg/L)后,两种养殖条件凡纳滨对虾己糖激酶(HK)、丙酮酸激酶(PK)、乳酸脱氢酶(LDH)和琥珀酸脱氢酶(SDH)活力的变化规律,并将两种养殖条件对虾的相关指标进行了比较。结果显示:(1)非离子氨胁迫后,两种养殖条件凡纳滨对虾鳃HK活力变化显著,而肌肉HK活力变化则不显著。(2)非离子氨胁迫后,两种养殖条件凡纳滨对虾鳃PK活力先升高,后逐渐恢复到正常水平;淡水养殖对虾肌肉PK活力则显著升高,而海水养殖对虾肌肉PK活力变化则不显著。(3)0.1 mg/L非离子氨胁迫后,两种养殖条件对虾鳃和肌肉LDH活力变化均不显著,而0.5 mg/L非离子氨对两种养殖条件对虾鳃和肌肉的LDH活力均具有显著影响。(4)非离子氨胁迫后,两种养殖条件对虾鳃和肌肉SDH活力均显著降低。研究表明,非离子氨胁迫对淡水养殖凡纳滨对虾呼吸代谢酶活力具有显著影响;非离子氨胁迫后,凡纳滨对虾有氧代谢迅速减弱,而无氧代谢在胁迫初期略有升高,随后减弱,推测非离子氨胁迫可能使对虾机体主要供能物质发生改变。     

恩诺沙星对凡纳滨对虾(Litopenaeus vannamei) CYP2基因表达及氨基比林-N-脱甲基酶活性的影响

以凡纳滨对虾(Litopenaeus vannamei)为研究对象,运用RT-PCR方法测定CYP2基因在凡纳滨对虾组织中的表达分布,并分析不同剂量恩诺沙星对凡纳滨对虾肝胰腺中CYP2基因表达和氨基比林-N-脱甲基酶(APND)活性的影响.结果显示,CYP2在肝胰腺、鳃、血淋巴、肌肉、甲壳、肠、胃、心脏和眼柄中均有分布,在肝胰腺中表达量最高,胃次之,血淋巴中表达量最低.口服低(15 mg/kg)、中(30 mg/kg)、高(60 mg/kg)3个剂量恩诺沙星药饵后,凡纳滨对虾肝胰腺中CYP2基因表达和APND活性较对照组均呈现下降趋势;药物浓度越高,基因表达量和酶活性越低,表明恩诺沙星可抑制CYP2在凡纳滨对虾体内的表达.在生产实践中联合用药时,应考虑到因恩诺沙星对CYP2的抑制作用而导致经其代谢的药物在生物体内的蓄积和毒性增强.     

恩诺沙星对凡纳滨对虾(Litopenaeus vannamei)CYP2基因表达及氨基比林-N-脱甲基酶活性的影响

以凡纳滨对虾(Litopenaeus vannamei)为研究对象,运用RT-PCR方法测定CYP2基因在凡纳滨对虾组织中的表达分布,并分析不同剂量恩诺沙星对凡纳滨对虾肝胰腺中CYP2基因表达和氨基比林-N-脱甲基酶(APND)活性的影响。结果显示,CYP2在肝胰腺、鳃、血淋巴、肌肉、甲壳、肠、胃、心脏和眼柄中均有分布,在肝胰腺中表达量最高,胃次之,血淋巴中表达量最低。口服低(15 mg/kg)、中(30 mg/kg)、高(60 mg/kg)3个剂量恩诺沙星药饵后,凡纳滨对虾肝胰腺中CYP2基因表达和APND活性较对照组均呈现下降趋势;药物浓度越高,基因表达量和酶活性越低,表明恩诺沙星可抑制CYP2在凡纳滨对虾体内的表达。在生产实践中联合用药时,应考虑到因恩诺沙星对CYP2的抑制作用而导致经其代谢的药物在生物体内的蓄积和毒性增强。     

亚硝态氮对草鱼离体肝细胞抗氧化体系的影响

为探究亚硝态氮对于草鱼离体肝细胞抗氧化系统的影响,将分离得到的离体草鱼肝细胞在含0（空白）,1,10和100 mg/L （浓度以氮计）的亚硝酸钠的M199生长培养基中,分别培养6、12、24、48和96 h后,检测肝细胞中超氧化物歧化酶（ SOD ）、过氧化氢酶（ CAT ）、γ-谷氨酰半胱氨酸合成酶（γ-GCS ）和谷胱甘肽转移酶（GST）的活性,谷胱甘肽（GSH）水平以及总抗氧化能力（TAC）。结果显示：高浓度的亚硝酸钠会引起肝细胞内的SOD、 CAT、 GST、γ-GCS活性显著升高;除100 mg/L实验组外,各实验组的 GSH水平均显著高于对照组,而TAC则随着亚硝酸钠浓度的升高,表现为先升高后下降的规律,且当亚硝酸钠浓度为10 mg/L时, TAC达最高水平。结果表明,较低剂量的亚硝态氮急性暴露可激活肝细胞抗氧化系统并促进其提高抗氧化能力,而高剂量亚硝态氮（100 mg/L）则显著降低了肝细胞的抗氧化能力。     

低鱼粉饲料中添加酶解豆粕对凡纳滨对虾生长性能和抗胁迫机能的影响

为研究在养殖过程中降低鱼粉用量的同时保持凡纳滨对虾良好的生长性能和抗逆能力,实验在含10%鱼粉的基础饲料中,分别添加酶解豆粕(PSM) 0%(A)、2.5%(B)、3.5%(C)、4.5%(D)、5.5%(E)制成5组等氮等能饲料,分别投喂初始体质量为(0.45±0.02) g的凡纳滨对虾幼虾8周,检测对虾生长性能及抗胁迫机能。结果显示,8周养殖实验结束后,各实验组对虾的终末体质量为14.65～15.38 g/尾,各组间对虾终末均重、成活率和饲料系数指标均无显著性差异;A组对虾肌肉粗蛋白质含量显著低于其他各实验组;C组、D组和E组对虾肌肉粗脂肪含量显著高于A组;各组间灰分和水分均无显著性差异;D组和E组对虾肝胰腺蛋白酶、淀粉酶、脂肪酶、血清溶菌酶和血清总超氧化物歧化酶活性(T-SOD)均显著高于A组;A组对虾血清丙二醛(MDA)含量显著高于D组和E组。人工急性感染高剂量副溶血性弧菌的胁迫实验中,A组对虾在弧菌感染48和60 h时的累积死亡率均显著高于D组对虾同期的累积死亡率;低剂量副溶血性弧菌人工急性感染后,在凡纳滨对虾鳃组织中检测Toll受体、免疫缺陷(IMD)和溶菌酶3种免疫相关基...     

Effect of dietary Bacillus licheniformis on growth,intestinal health,and resistance to nitrite stress in Pacific white shrimp Litopenaeus vannamei

The aim of this study was to evaluate effects of Bacillus licheniformis supplementation on growth, intestine digestive, antioxidant and metabolic capacity, intestine short-chain fatty acids content, and intestine microbiota composition of the Pacific white shrimp Litopenaeus vannamei. In total 2700 shrimp (initial weight 2.5?±?0.1 g/shrimp) were randomly distributed into six tanks (450 shrimp/500-L tank) and fed at 28?±?0.5 ℃ for 35 days (four times/day) with control diet and experimental diet supplemented with 10⁸ CFU/g B. licheniformis, followed by an acute nitrite stress for 10 days. At the end of the feeding trial, shrimp dietary B. licheniformis showed improved weight gain, specific growth rate, survival rate after nitrite stress, and decreased feed conversion rate compared to control group. And acetic acid and butyric acid content in the intestine of shrimp dietary B. licheniformis increased significantly except for propionic acid content. In addition, activities of amylase, lipase, and trypsin and activities of glutamine synthetase, hexokinase, and malate dehydrogenase increased significantly compared to control group. After shrimp were exposed to nitrite stress for 10 days, glutathione peroxidase, peroxidase, total antioxidant capacity, and superoxide dismutase levels were still higher in dietary B. licheniformis-shrimp, which showed that B. licheniformis enhanced the resistance to environmental stressor such as nitrite from the level of immune. The 16S rRNA sequencing showed that B. licheniformis increased diversity and abundance of some bacteria. In particular, the abundance of Proteobacteria and Planctomycetes decreased, and the abundance of Firmicutes and Bacteroidetes increased. These results revealed that B. licheniformis could improve the growth performance, increased intestine short-chain fatty acids (SCFA) content, change intestine digestive and metabolic enzyme activity, and regulated microbiota composition, so enhance the intestine antioxidant ability of shrimp subjected to nitrite stress, which is beneficial for shrimp aquaculture.

     

转vp28蓝藻口服剂对凡纳滨对虾抗白斑综合征病毒能力及免疫反应的影响

为探讨转vp28蓝藻(Anabaena sp.PCC7120)口服剂对凡纳滨对虾抗白斑综合征病毒能力及其相应的免疫反应,本研究将此口服剂免疫幼虾7 d,再分别通过投喂攻毒和浸泡攻毒,测定其存活率及相应的免疫指标。投喂攻毒和浸泡攻毒的实验组存活率分别为78.8%和83.19%,表明该口服剂能显著增强对虾抗白斑综合征病毒的能力。蓝藻口服剂免疫对虾的酶活性检测结果显示,超氧化物歧化酶(SOD)、酚氧化酶(PO)、过氧化氢酶(CAT)和碱性磷酸酶(AKP)活性在免疫后2 h均有上升趋势,且在48或96 h达到最高值,这表明该口服剂能引起对虾体内酶活性变化。投喂攻毒的对虾酶活性检测结果显示,实验组攻毒后的对虾肝胰腺SOD活性分别比阳性对照组、野生型组、空载体组显著提高42.10%、32.26%和16.04%,且攻毒后的肌肉SOD活性分别比阴性对照组、阳性对照组、野生型组和空载体组略微提高17.70%、11.50%、15.00%以及10.00%。实验组攻毒后的对虾肝胰腺PO、CAT和AKP活性比阳性对照组分别提高12.17%、88.80%和240.07%,比野生型组分别提高21.49%、30.90%和100%;酸性磷酸酶(ACP)活性比阴性对照组略微提高,而在肌肉中各组ACP活性无显著性差异。同时浸泡攻毒组结果与投喂攻毒组具有类似的趋势。浸泡攻毒的实验组CAT和AKP活性显著高于其余处理组,且CAT活性比投喂攻毒更为显著。浸泡攻毒的实验组肝胰腺PO活性显著高于阳性对照组、野生型组和空载体组,而各组肌肉ACP活性无显著性差异。研究表明,转vp28蓝藻口服剂能够增强凡纳滨对虾抗病能力并延缓对虾死亡。转vp28蓝藻PCC7120本身可作为幼虾饵料直接投喂,无需提取纯化,有望大规模应用于对虾养殖产业。     

Response of facilitative glucose transporter 1 to salinity stress and dietary carbohydrate nutrition in white shrimp Litopenaeus vannamei

Facilitative glucose transporter 1 (GLUT1) is a transporter protein for glucose transport via the plasma membrane of the cells to provide energy through carbohydrate metabolism. GLUT1 cDNA from Litopenaeus vannamei was obtained and analysed in this study. Full‐length GLUT1 cDNA is 2062 bp long and contained a 1506‐bp ORF encoding a 502 amino acid protein, a 270‐bp 5′UTR and a 284‐bp 3′UTR. When shrimp were under acute low salinity stress, the expression in hepatopancreas, muscle, gill and eyestalk was all up‐regulated at 12 h (P < 0.05) and 96 h (P < 0.05), while the expression in the four tissues was all down‐regulated at 6 h (P < 0.05) and 48 h (P < 0.05) . The expression in the muscle of shrimp at water salinity of 3 was lower than that at water salinity of 30 independent of dietary carbohydrate levels, while expression in hepatopancreas, gill and eyestalk was up‐regulated at 200 and 300 g kg^?1 carbohydrate levels. The expression in all tissues fed glucose was up‐regulated when compared to the expression in shrimp held at a water salinity of 30. This study suggests that GLUT1 is a conserved protein in L. vannamei, and changes in expression due to environmental salinity and dietary carbohydrate level and source.     

Effect of lignite fulvic acid on growth,antioxidant ability,and HSP70 of Pacific white shrimp, <Emphasis Type="Italic">Litopenaeus vannamei</Emphasis>

This study was conducted to evaluate the effects of fulvic acid (0, 0.3, 0.6, 0.9, and 1.2%) as feed additive on growth, feed utilization, antioxidant ability, and HSP70 in hemolymph and hepatopancreas of juvenile white shrimp Litopenaeus vannamei (average weight 2.5 g) reared under experiment conditions. Shrimp were stocked at a density of 625 shrimps m^?3 for 60 days in net cages submerged in recirculating tanks. At the end of the experiment, specific growth rates and survival rates of shrimp in treatment groups fed with 0.6, 0.9, and 1.2% fulvic acid were higher compared to that of the control group. Shrimp fed 0.6, 0.9, and 1.2% fulvic acid had significantly lower feed conversion rates than those fed control diet. The optimum dietary fulvic acid requirement for juvenile shrimp based on weight gain was 0.897%. Furthermore, superoxide dismutase activity and peroxidase activity increased significantly, while malonaldehyde content decreased in the hemolymph and hepatopancreas of shrimp fed 0.9 and 1.2% dietary fulvic acid. Glutathione content increased obviously in hemolymph of shrimp fed 0.6, 0.9, and 1.2% fulvic acid. In hepatopancreas, glutathione content was significantly higher in shrimp supplemented with 1.2% fulvic acid. HSP70 decreased obviously in hemolymph of shrimp fed 0.9 and 1.2% fulvic acid, while shrimp fed with 0.6 and 0.9% fulvic acid showed lower HSP70 level in hepatopancreas. The results of this study demonstrated that dietary fulvic acid could improve survival rates, growth, feed utilization, antioxidant capability, and stress resistance of juvenile L. vannamei reared under intensive stocking conditions.     

凡纳滨对虾LvRab5B蛋白与IHHNV病毒蛋白的互作

为了探究LvRab5B蛋白在凡纳滨对虾抗病毒感染中的作用,实验分别构建了LvRab5B蛋白在昆虫和酵母细胞中的融合表达载体,将不同的载体导入不同的细胞中,利用免疫荧光和酵母双杂交的方法研究了Lv Rab5B蛋白在昆虫细胞中的表达以及Lv Rab5B蛋白与病毒IHHNV之间的互作关系;通过qRT-PCR方法研究了该蛋白在健康对虾不同组织中的表达情况以及凡纳滨对虾分别感染IHHNV和WSSV后不同时间点的相对表达量。结果显示,Lv Rab5B基因融合蛋白能够在昆虫细胞中表达;Lv Rab5B蛋白与IHHNV病毒衣壳蛋白CP无相互作用,而与非结构蛋白NS1相互作用明显,与非结构蛋白NS2作用较弱。qRT-PCR结果显示,LvRab5B基因在凡纳滨对虾心脏、鳃腺、肠道、胃、肝胰脏和肌肉中都表达,在肠道中表达量最高,肝胰脏次之;Lv Rab5B蛋白在凡纳滨对虾机体感染病毒前后的表达情况不同,感染初期表达降低,随后迅速上升,末期下降。研究表明,LvRab5B基因参与凡纳滨对虾抵抗IHHNV和WSSV病毒的先天免疫过程,为进一步研究Lv Rab5B蛋白在对虾机体中的免疫功能及作用机制奠定了基础。     

发酵豆粕替代鱼粉对凡纳滨对虾生长、免疫相关酶及免疫相关基因表达的影响

从免疫相关酶活及基因转录水平角度探讨发酵豆粕替代鱼粉对凡纳滨对虾健康生长及免疫机能机制的影响。实验设置5种实用饲料,以30%鱼粉组(FM)为对照组,分别用4%(FSM4)、8%(FSM8)、12%(FSM12)和16%(FSM16)的发酵豆粕,替代9.7%、19.4%、29.1%和38.8%鱼粉,分为4个处理组,饲养体质量为(7.62±0.23)g的凡纳滨对虾60 d后,统计生长性能,检测肌肉营养成分、血清及肝胰腺免疫相关酶活性,肝胰腺HSP70和鳃Toll受体、IMD、溶菌酶(LZM)免疫相关基因m RNA的表达水平。结果显示:(1)与对照组相比,发酵豆粕替代鱼粉对凡纳滨对虾成活率无显著影响;过低或过高水平的发酵豆粕替代鱼粉皆会影响凡纳滨对虾的特定生长率。(2)除FSM12组外,肌肉粗蛋白含量发酵豆粕替代组均低于对照组;粗脂肪含量随着发酵豆粕替代量的升高而降低,FSM16组最低。(3)血清谷丙转氨酶活FSM4和FSM16组显著高于对照组;谷草转氨酶活FSM4组最高,而FSM8组最低;除FSM12组外;碱性磷酸酶活性发酵豆粕替代组显著高于对照组;除FSM16组外,血清总蛋白与肝胰腺丙二醛含量发酵豆粕替代组与对照组无显著性差异。(4)随着发酵豆粕替代量增加,鳃Toll受体m RNA表达呈上升趋势,鳃IMD m RNA表达则呈先升后降趋势,发酵豆粕替代比例过高会降低鳃LZM m RNA表达水平,而肝胰腺HSP70 m RNA表达量则随着发酵豆粕替代比例增加呈上升趋势。综上所述,发酵豆粕适量替代鱼粉对凡纳滨对虾生长性能无显著影响,并可提高免疫相关酶活,改变免疫相关基因的表达。本实验条件下适宜发酵豆粕用量为8%~12%;替代量过高,会引起机体的过度应激。     

Pharmacokinetics of enrofloxacin and its metabolite ciprofloxacin in Pacific white shrimp <Emphasis Type="Italic">Litopenaeus vannamei</Emphasis> after multiple-dose oral administration

The present study was designed to explore pharmacokinetics (PK) of enrofloxacin and its metabolite ciprofloxacin in Pacific white shrimp Litopenaeus vannamei after multiple-dose oral administration of enrofloxacin (30 mg/kg dose per 12 h and continuous feeding for 3 days). Enrofloxacin and ciprofloxacin concentrations in hemolymph, hepatopancreas, and muscle of the shrimp were simultaneously determined by high-performance liquid chromatography. PK parameters were analyzed based on statistical moment theory. Meanwhile, the relationship of pharmacokinetics/pharmacodynamics (PK/PD) was established based on drug concentration of hemolymph and in vitro antibacterial activity (MIC value). Results showed faster absorption of enrofloxacin in hemolymph (T_max?=?1 h) and muscles (T_max?=?1 h) than that in hepatopancreas (T_max?=?3 h) after the first oral administration. In multiple-dose oral administration, slight accumulation of enrofloxacin occurred in the hemolymph and hepatopancreas, while in the muscle, enrofloxacin concentration showed a significant decline following multiple administration. Tissue distribution of enrofloxacin and ciprofloxacin both followed the order hepatopancreas?>?hemolymph?>?muscle, with significantly higher ciprofloxacin concentration in hepatopancreas than in hemolymph (approximately 10-fold) and muscles (approximately 50-fold), indicating that the hepatopancreas is the main organ involved in metabolism of enrofloxacin in Pacific white shrimp. After multiple-dose administration, C_max/MIC and AUC_0–24/MIC values showed that the therapeutic regimen in this study could be remarkably effective in prevention and treatment of Vibrio infection in Pacific white shrimp.     

亚硝酸盐氮胁迫对鳙血液生化指标以及组织HSP70 mRNA表达水平的影响

为了探讨亚硝酸盐氮胁迫对鳙[初均重:(180.05±0.092)g]血液生化指标和组织热休克蛋白70基因表达水平的影响,实验选用170尾鳙,暴露于48.634 mg/L亚硝酸盐氮96 h后,进行96 h恢复实验。并在胁迫0、6、12、24、48、72和96 h以及恢复12、24、48、72和96 h时采集样品。结果显示,胁迫6 h后,血清皮质醇含量和谷丙转氨酶活性显著升高;胁迫12 h后,血清中葡萄糖含量显著升高;胁迫24 h后,血清总胆固醇含量开始显著降低;胁迫48 h后,血清总蛋白和甘油三酯含量开始显著降低,三碘甲状腺原氨酸含量和谷草转氨酶活性则显著升高;胁迫72 h后,血清低密度脂蛋白和高密度脂蛋白含量开始显著降低。恢复96 h后,鱼体血清生理指标大多都已恢复至胁迫前水平,而组织热休克蛋白70 mRNA表达水平的差异显示,头肾抗亚硝酸盐氮响应最快,其次为鳃和肠道,而脾脏热休克蛋白70 mRNA表达水平在恢复12 h时显著升高;恢复96 h后,除鳃组织外,肾脏、肠道和脾脏的热休克蛋白70 mRNA表达量均恢复至胁迫前水平。研究表明,亚硝酸盐氮对鳙的蛋白质代谢、脂质代谢和糖代谢均产生影响,并且诱导部分组织热休克蛋白70 mRNA的表达,而鳙对水体中高浓度的亚硝酸盐氮应激6 h即可产生快速应答,并启动防损伤自我保护机制,促进新陈代谢水平,保护机体免受应激损伤。     

A Toxicokinetic Study of Oxytetracycline Antibiotics in Farmed Pacific White Shrimp,Penaeus vannamei

Toxicokinetics has demonstrated abnormal signs in drug distribution/disposition without waiting until the drug damages the tissues/organs. It is a study of the kinetic assessment of administering high‐dose of oxytetracycline (OTC) to white shrimp. Male Penaeus vannamei in the C–D₀ molting stage, were force fed with medicated feeds at various accurate dose levels including 500, 1000, and 2500 mg/kg‐body weight (BW). After dosing with different time intervals, hemolymph, muscle, and hepatopancreas were collected, and assayed for OTC by validated high‐performance liquid chromatography method. The simulated profile based on the maximum recommended dose was tested to approach the systemic level where the drug was anticipated not to cause significant toxic responses. OTC kinetic profiles in the hemolymph were fitted into the flow limited model having r² value between 0.8341 and 0.9373. The relative affinities for the muscle and hepatopancreas changed at dose level exceeding 1000 mg/kg BW. Although hepatopancreatic clearance was non‐linearly related with dose, the persistence of OTC in muscle after 2500 mg/kg BW dosing was observed to indicate abnormalities in drug distribution/disposition. It was hypothesized that the pharmacokinetic alteration after extreme dosing was because of induction of functional abnormalities in hepatopancreas. In addition, a single administration of OTC at 1000 mg/kg BW was anticipated to be a tolerated dose.