操作胁迫对大黄鱼幼鱼的影响

研究操作胁迫(追赶惊扰)对大黄鱼(Pseudosciaena crocea Richardson)幼鱼的生长、行为、肝脏、脾脏、免疫功能等方面的影响.实验用大黄鱼幼鱼全长(5.85±0.45)cm,实验共设3个组对照组、实验组1(每日操作胁迫1次)、实验组2(每日操作胁迫2次),每组2个重复.分别于实验开始后第10天、20天、30天,取样测定其全长、体质量、脾脏重以及肝脏重,计算脾系数和肝系数;断尾取血做血涂片,在油镜下进行白细胞分类计数,并对各项指标进行统计分析.结果表明,长期的剧烈操作胁迫会显著抑制大黄鱼幼鱼的生长,同时也影响其肝脾脏功能和机体免疫机能,如增加大黄鱼幼鱼脾系数(即脾肿大),肝脏的合成代谢先受到抑制;各种白细胞比率受剧烈操作胁迫(每日2次胁迫)影响发生显著变化,嗜中性粒细胞和单核细胞在实验前期(10 d)或中期(20 d)显著增多,而淋巴细胞则明显减少,但在实验末期均又恢复正常水平,其原因可能是大黄鱼的免疫机能对长期操作胁迫表现一定的适应性.     

复方抗应激制剂对仔猪断奶应激的影响

本试验以新荣Ⅰ系３５日龄断奶仔猪为试验动物，探讨复方抗应激制剂对仔猪断奶应激的影响及其机理。结果，血清总蛋白含量增加（Ｐ＜０．０５），血清尿素氮、血清皮质醇、血清葡萄糖下降（Ｐ＜０．０５）．血清无机Ｐ、ＣＩ－、Ｎａ~＋、Ｋ~＋含量升高（Ｐ＜０．０５）。表明该制剂可通过这些途径或方面对仔猪断奶应激产生防治作用。     

有水与无水保活运输对大菱鲆生理应激及鱼肉品质的影响

为探究大菱鲆分别在有水及无水条件下运输过程中生理生化指标及肌肉品质的变化,为大菱鲆的保活运输提供参考。将大菱鲆进行暂养、降温、充氧包装后进行模拟运输,并在运输不同时间段取样,检测大菱鲆生理生化指标及肌肉指标。结果显示,模拟运输18 h后,有水运输组和无水运输组中的大菱鲆存活率仍为100%。大菱鲆肌肉中水分含量、粗脂肪、pH、糖原、三磷酸腺苷(ATP)和腺苷酸(AMP)含量显著降低,乳酸和肌苷酸(IMP)含量升高。其中,有水运输组中的大菱鲆AMP含量降低了38.65%,IMP含量增加了29.1%,无水运输组中的大菱鲆AMP含量降低了12.83%,IMP含量增加了28.47%。大菱鲆血液生化指标中,葡萄糖、尿素氮和皮质醇含量显著升高。运输过程后,无水运输组中大菱鲆生理应激及能量代谢指标的变化幅度均小于有水运输处理组中的大菱鲆。此外,低温无水运输组大菱鲆肌肉中呈味核苷酸IMP和AMP含量显著高于有水运输组,表明低温无水运输增加了大菱鲆呈鲜味物质的含量,提高了鱼肉风味。研究表明,低温无水保活技术在活鱼运输中具有广泛的应用前景。     

Effects of acute environmental and handling exposure on physiology and fillet quality of market‐sized Channel Catfish

Catfish Ictalurus spp. are subjected to stressful conditions during harvest, which may be linked to fillet coloration and quality. Poor water quality in ponds, socks or hauling tanks, as well as handling stress, have been suggested to cause red fillets in catfish; however, chronic exposure has not resulted in red fillets. Short‐term occurrences of extreme poor water quality, particularly low dissolved oxygen, high carbon dioxide and high temperature, may occur in ponds or during harvest. Therefore, market‐sized Channel Catfish Ictalurus punctatus were acutely exposed (12 hr) to one of the three water quality treatments while confined during a simulated socking procedure and evaluated for stress responses by means of change in blood parameters and fillet quality. In fish subjected to the extreme treatment, hematocrit, plasma cortisol, glucose and lactate levels increased, with 22% mortality, indicating highly stressful conditions. In fish subjected to moderate and typical (control) treatments, cortisol increased but a lack of change or decrease in glucose and lactate indicated minimal anaerobic metabolism. Only one red fillet was produced by the extreme treatment and two by the typical treatment; therefore, the results suggest red fillets are not a product of poor water quality compounded by handling during harvest.     

刀鲚POMC基因的cDNA克隆及其应激应答

为了研究刀鲚(Coilia nasus)阿黑皮素原(proopiomelanocortin,POMC)基因的应激应答及调控,克隆了刀鲚POMC基因的c DNA全长。刀鲚POMC基因的c DNA全长2030 bp,编码区699 bp,编码232个氨基酸。二级结构预测显示,刀鲚POMC包括信号肽(signal peptide)、N末端区(N-terminal region,NPP)、促肾上腺皮质激素结构域(adrenocorticotropic hormone,ACTH)、β-脂解素(β-LPH)、α-促黑素(α-MSH)、促肾上腺皮质激素样垂体中叶多肽(CLIP)、γ-脂解素(γ-LPH)、β-促黑素(β-MSH)和β-内咖肽(β-EP)结构域。运用荧光定量的方法检测了该基因在刀鲚不同组织中的表达分布。结果显示,POMC在健康刀鲚的脑高表达,鳃、肾、精巢相对高表达,肝、脾、肠、头肾、肌肉和卵巢中微量表达。运输胁迫后,POMC基因的表达量显著下降(P0.05);10‰ NaCl组4 h和6 h POMC基因的表达量显著上调(P0.05),6 h的表达量恢复至应激前。POMC基因在脂肪代谢及应激调控中发挥重要的功能,本研究结果可为该基因在刀鲚后续育种及应激调控工作提供重要基础。     

脊尾白虾丝氨酸蛋白酶抑制剂基因克隆及表达分析

采用RACE方法获得了脊尾白虾(Exopalaemon carinicauda)丝氨酸蛋白酶抑制剂serpin基因的cDNA序列。该基因全长1 516 bp, 开放阅读框1 245 bp, 编码414个氨基酸, 其预测分子量为45.06 kD, 理论等电点为5.694, 并含有两个糖基结合位点。同源性分析发现其与斑节对虾(Penaeus monodon)同源性最高, 达到49%。组织表达分析表明, serpin基因在脊尾白虾血细胞中表达量最高, 其次是肝胰腺和鳃组织, 在肌肉中表达量最低。不同盐度胁迫后脊尾白虾的血细胞serpin基因表达量在盐度胁迫8 h时显著高于对照组(P<0.05), 肝胰腺组织中serpin基因表达量在盐度胁迫后2 h和24 h出现明显峰值, 且显著高于对照组(P<0.05)。上述结果表明, 脊尾白虾serpin基因参与了急性盐度胁迫下机体的应激反应。本研究通过克隆脊尾白虾酚氧化酶原激活系统中的丝氨酸蛋白酶抑制剂基因cDNA全长, 分析盐度胁迫后其在血细胞和肝胰腺组织中的表达变化规律, 以期为脊尾白虾的健康养殖提供理论基础和参考依据。

     

Effects of stocking density and food deprivation‐related stress on the physiology and growth in adult Scortum barcoo (McCulloch & Waite)

Two consecutive experiments were conducted to investigate the physiological responses of Jade perch (Scortom barcoo) to different stocking densities over a 30‐day period and to stress resulting from food deprivation over a 10‐day period. Groups of Jade perch were reared in recirculating tanks at three stocking densities (120, 180 and 270 fish m^?3). Fish were weighed and blood samples were taken at the beginning of the experiment (P1) and after 30 days (P2). Feeding was then stopped and fish were sampled again 10 days later (P3). Blood samples were analysed for serum level of cortisol (COR), glucose (GLU), total protein (TP), triglycerides (TG), lysozyme (LYS) activity and alkaline phosphatase (ALP) activity. Significant changes were observed in average body weight and serum COR, TG, LYS and ALP activity in response to stocking density. No significant difference was found between stocking density treatments concerning the serum TP and GLU. The results showed that fish performed better at a stocking density of 180 fish m^?3. Food deprivation for 10 days resulted in significant changes in ALP activity and LYS activity, TP and GLU concentrations and final average body weight but not in COR and TG levels.     

Thermal stress responses of a sterile mutant of Ulva pertusa (Chlorophyta)

SUMMARY: The thermal stress responses of a sterile mutant of the marine alga Ulva pertusa were investigated at 20°C and 30°C. The amounts of the photosynthetic pigments, β-carotene, chlorophylls a and b , lutein, neoxanthin, and violaxanthin, were 1.4–2.4 times higher in the 30°C-cultivated alga than in the 20°C-cultivated alga. The free amino acids, asparagine, aspartic acid, glutamine, glutamic acid, glycine, and serine, were abundant in the 20°C-cultivated alga, and increased 1.9–10.5-fold in response to thermal stress (30°C). Total carbon and nitrogen contents also increased in the 30°C-cultivated alga. Sodium dodecylsulfate-polyacrylamide gel electrophoretic patterns of total proteins extracted from both temperature-treated algae showed the increases of 20, 25, and 90 kDa proteins in the 30°C-cultivated alga. Isozyme assays for 20 enzymes showed a different banding pattern only in the case of glutamate dehydrogenase (GDH). Although it was observed that both temperature-treated algae possessed NAD⁺- and NADP⁺-specific GDH, the 30°C-cultivated alga had an additional NADP⁺-specific GDH (NADP-GDH). These results suggest that NADP-GDH compensates for the thermally induced decreases in nitrogen assimilation efficiency and thereby regulates nitrogen metabolism under conditions of temperature stress.     

刀鲚PPARγ基因的cDNA克隆及其应激应答

旨在研究刀鲚(Coilia nasus)过氧化物酶体增殖物激活受体γ(peroxisome proliferator activated receptor, PPARγ)基因的应激调控表达,克隆并获得了刀鲚PPARγ基因的cDNA全长。刀鲚PPARγ基因的cDNA全长1951 bp,开放阅读框1470 bp,预测编码489个氨基酸。刀鲚PPARγ包括4个功能结构域,即A/B区, DNA结合区(DNA binding domain, DBD区),铰链区,配体结合区(ligand binding domain, LBD区)。运用荧光定量PCR (real time quantitative PCR, RT-qPCR)检测刀鲚PPARγ基因在不同组织、运输胁迫和胚胎发育时期的表达。结果显示,刀鲚PPARγ在各组织中均有表达,其中在肝中表达量最高,在脑、肠、心脏、肾、头肾、肌肉中相对高表达,在鳃和脾中微量表达。运输胁迫过程中, PPARγ基因表达显著上调(P0.05),在4 h达到峰值,随后显著降低,但仍高于对照组。PPARγ在胚胎发育时期各时期均表达,其中在受精卵时期高表达,随后表达量急剧降低,并在此后的时期一直处于较低的表达水平。PPARγ基因在应激过程中发挥重要作用,也是胚胎发育过程中重要的基因。本研究为刀鲚的人工繁育和应激调控提供了理论基础。     

中国对虾ATG5基因的克隆及其在pH、碳酸盐碱度胁迫下的表达分析

采用cDNA末端快速扩增(RACE)技术获得中国对虾(Fenneropenaeus chinensis) ATG5基因cDNA全长,命名为FcATG5。利用实时荧光定量技术分析了FcATG5的组织表达及其在pH和碳酸盐碱度胁迫下的表达特征,并利用RNAi技术验证其功能。基因分析显示,FcATG5 cDNA全长为2225 bp,开放阅读框为810 bp,编码269个氨基酸,预测其编码的蛋白质分子量为31.103 kDa,理论等电点为5.59,为疏水性蛋白,包含1个APG5自噬相关蛋白结构域,无跨膜结构,不包含信号肽。同源性和系统进化分析显示,FcATG5具有高度保守性,与凡纳滨对虾(Litopenaeus vannamei)同源性最高(98.14%)。组织表达分析显示,FcATG5在中国对虾各组织中均有表达,肌肉中表达量最高(P<0.05),血淋巴细胞中最低(P<0.05)。pH胁迫后48 h,FcATG5在鳃中的表达量最低,为对照组的1.68倍;胁迫后96 h最高,为对照组的2.67倍。碳酸盐碱度胁迫后12 h,FcATG5在鳃中表达量最高,为对照组的2.77倍;胁迫后96 h最低,为对照组的1.30倍。干扰实验结果显示,pH和碳酸盐碱度胁迫下,沉默FcATG5基因会使中国对虾死亡率显著增高(P<0.05),表明该基因的表达量越高,越有利于中国对虾存活。实时定量结果表明,FcATG5在pH、碳酸盐胁迫下的表达量均显著升高(P<0.05),推测自噬可能参与中国对虾应对非生物胁迫的调控。本研究结果对水生动物特别是甲壳动物中细胞自噬研究具有重要的借鉴意义,有助于推进中国对虾盐碱水养殖的研究进程。     

罗非鱼抗逆性研究

研究了奥尼罗非鱼和吉富罗非鱼对低温和重金属的抗逆性。抗冻性实验结果表明,奥尼罗非鱼的抗冻性优于吉富罗非鱼。抗冻性较好的奥尼罗非鱼对重金属的抗逆性研究结果表明,在相同浓度的不同重金属作用下,奥尼罗非鱼幼苗对受试3种重金属离子(Pb2+、Cr6+、Cu2+)的抗逆性均随着作用时间的延长而下降。在相同条件下,对受试3种重金属离子的抗逆性:Cr6+Cu2+Pb2+。     

The effects of vitamins C and E on the growth,tissue accumulation and prophylactic response to thermal and acidic stress of hybrid catfish

This study investigated the effects of the co‐supplementation of vitamins C (0, 500, and 1000 mg kg^?1) and E (0, 62.5, and 125 mg kg^?1) on the growth performance, haematology and the modulation of blood stress indicators and immune parameters in hybrid catfish (Clarias macrocephalus × Clarias gariepinus) under combinations of thermal and acidic stress. Supplementation of vitamins C and E influenced the growth, haematological indices, serum chloride, plasma protein and immune parameters (lysozyme, total immunoglobulin and alternative complement haemolytic assay) (P < 0.05). Although vitamins C and E did not prevent a significant reduction in serum chloride, they minimized not only the modulation of blood glucose and plasma protein, but also the reduction in immune parameters (P < 0.05) owing to stress. Our results demonstrated that co‐supplementation of 500 mg kg^?1 vitamin C and 125 mg kg^?1 vitamin E, or 1000 mg kg^?1 vitamin C alone, for four weeks and co‐supplementation of both vitamins at low levels (vitamins C at 500 mg kg^?1 and E at 62.5 mg kg^?1) for eight weeks had beneficial effects on the growth, amelioration of stress‐mediated adverse changes in the physiological and immunosuppressive responses of hybrid catfish under stressful conditions.     

pH、氨氮胁迫对中国对虾HSP90基因表达的影响

研究了pH、氨氮胁迫对中国对虾Fenneropenaeus chinensis血细胞、肝胰腺、鳃和肌肉组织HSP90基因时空表达的影响.分别将中国对虾暴露于pH7.0、9.0的水体中148h和不同氨氮浓度的水体中96h,结果表明,pH（7.0,9.0）胁迫条件下中国对虾鳃、肌肉和血细胞HSP90基因表达均上调,肝胰腺HSP90基因表达对两种pH胁迫差异明显：pH7.0胁迫条件下,HSP90基因表达3h达峰值后明显降低;pH 9.0胁迫时,HSP90基因表达水平逐渐升高,整个胁迫过程中均显著高于对照组（P＜0.05）,说明中国对虾肝胰腺组织是高pH胁迫的响应器官.6mg/L氨氮浓度组鳃和肌肉组织HSP90基因表达水平24h达最高值,分别为对照组的5.46和1.55倍;各胁迫组肝胰腺和血细胞HSP90基因表达水平分别于6h和48h达到最高值,为对照组的1.33～2.08倍和2.20～5.45倍.肝胰腺组织对氨氮胁迫表现敏感,短时间内（6h）通过上调HSP90基因表达水平保护细胞;鳃组织HSP90基因表达波动范围最大,说明鳃组织需要更高表达量的HSP90保护细胞.当氨氮浓度持续48～96h维持在2～6mg/L,各组织HSP90基因表达水平显著降低.     

调控应激的营养途径

本文分别从能量、蛋白质、氨基酸、矿物质、维生素和添加剂等方面对动物应激的影响进行了阐述,并综述了调控应激的营养途径。     

Oxidative stress in juvenile chinook salmon, Oncorhynchus tshawytscha (Walbaum)

Juvenile chinook salmon, Oncorhynchus tshawytscha (Walbaum), were held in 8–11°C freshwater, starved for 3 days and subjected to a low‐water stressor to determine the relationship between the general stress response and oxidative stress. Lipid peroxidation (LPO) levels (lipid hydroperoxides) were measured in kidney, liver and brain samples taken at the beginning of the experiment (0‐h unstressed controls) and at 6, 24 and 48 h after application of a continuous low‐water stressor. Tissue samples were also taken at 48 h from fish that had not been exposed to the stressor (48‐h unstressed controls). Exposure to the low‐water stressor affected LPO in kidney and brain tissues. In kidney, LPO decreased 6 h after imposition of the stressor; similar but less pronounced decreases also occurred in the liver and brain. At 48 h, LPO increased (in comparison with 6‐h stressed tissues) in the kidney and brain. In comparison with 48‐h unstressed controls, LPO levels were higher in the kidney and brain of stressed fish. Although preliminary, results suggest that stress can cause oxidative tissue damage in juvenile chinook salmon. Measures of oxidative stress have shown similar responses to stress in mammals; however, further research is needed to determine the extent of the stress–oxidative stress relationship and the underlying physiological mechanisms in fish.     

Tolerance of the shrimp Litopenaeus stylirostris, Stimpson 1894, to environmental stress: interindividual variability and selection potential for stress-resistant individuals

Our study showed that osmoregulatory capacity (OC) of shrimp from the same clutch displayed interindividual variability. When environmental salinity decreases, this variability increases. Thus, at isoosmotic point (sea‐water salinity ≈26), the coefficient of variation calculated for measured OC was 2.7%, whereas it was 8.2% for sea‐water salinity ≈1.5. In terms of haemolymph osmolality, the interindividual difference can reach up to 45.8% for the same water salinity level. The mean OC of individuals that have survived a series of salinity and temperature shocks is significantly greater than the mean value recorded within their original population. This increase in OC was maintained beyond the one or two moulting periods that these shrimp experienced during our experiment.     

Further evidence of the equivocal effects of cortisol on in vitro steroidogenesis by ovarian follicles of rainbow trout Oncorhynchus mykiss

Previous studies on salmonids have yielded equivocal results as to the role of cortisol in directly inhibiting ovarian steroidogenesis. In an effort to determine why this might be so, isolated ovarian follicles of rainbow trout were incubated with and without cortisol under varying conditions of gonadotropin or steroid precursor stimulation, incubation time and temperature. Cortisol at concentrations of 100–1000 ng ml–1 suppressed basal production of 17-estradiol (E2) in only 4 out of 20 experiments, had no effect on human chorionic gonadotropin (hCG)-stimulated production, and no suppressive effect on 17-hydroxyprogesterone (17P)-stimulated production in 14 experiments, but increased E2 production in response to 17P in 2 experiments. Cortisone had no effect on basal E2 production, suggesting that cortisol was unlikely to be exerting any effect indirectly after further metabolism. Extended incubation times at 12 °C resulted in overall decreased levels of E2 in incubation media, but this had no obvious effect on patterns generated by treatment with cortisol. Extended incubation at 18 °C did change the pattern of response to treatment with cortisol in 1 out of 3 experiments. All incubations examined produced substantial amounts of E2-glucuronide but this showed no obvious relationship to whether or not inhibition of E2 production by cortisol was observed. Effect of stress history was examined by incubating follicles from stressed or unstressed fish. In follicles from fish nearing the end of vitellogenesis, stress resulted in reduced production of both testosterone and E2 in response to hCG, but increased conversion of 17P to E2. The same effect was not observed in follicles from fish at an earlier stage of vitellogenesis. Measurement of E2 uptake by follicles from selected experiments showed that follicles contained considerable amounts of E2 and were potentially a sink for steroid produced during incubation. The experiments show that a consistent effect of cortisol on ovarian steroidogenesis remains elusive, but that stimulatory effects are as likely to occur as inhibitory effects. All responses are potentially further confounded by loss of free steroid from the medium by conjugation or absorption into the oocytes.     

低氮、磷胁迫对坛紫菜叶状体生理生化特征的影响

以坛紫菜耐低氮(N)、磷(P)品系9号Ⅳ叶状体为材料,研究了低N、P胁迫不同时间水平对坛紫菜品质及自由基含量、过氧化氢(H₂O₂)含量、丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、过氧化氢酶(CAT)活性和游离脯氨酸(Pro)含量等生理指标的影响。结果表明,在低N、P胁迫条件下,作为坛紫菜品质重要指标的光合色素、粗蛋白和游离氨基酸含量均显著下降,而其余各项生理指标均随胁迫时间增加表现为动态变化的过程,由此推测耐低N、P型坛紫菜叶状体应答低N、P胁迫的生理过程为:低N、P胁迫→活性氧含量上升→细胞膜氧化受损,产生大量膜脂过氧化物→细胞感受到过量的活性氧信号→抗氧化系统和渗透压调节系统共同响应,清除活性氧→自由基含量下降。该实验结果为全面了解坛紫菜应答低N、P胁迫的生理机制奠定了基础,同时也为后续坛紫菜抗逆新品种的选育提供了理论指导。     

Physiological effects of stocking density on the fish Piaractus mesopotamicus fed with red seaweed (Pyropia columbina) and β‐carotene‐supplemented diets

This study aimed at investigating the physiological responses of Piaractus mesopotamicus exposed to high stocking density and the potential protective role of supplemented diets. Fish were fed with basal, red seaweed (Pyropia columbina) or β‐carotene‐supplemented diets for 90 days. Then, fish were distributed at low (1.5 g/L) and high (22 g/L) stocking densities for 15 days. Fish exposed to the high density showed increased hepatosomatic index, haemoglobin content and mean corpuscular haemoglobin concentration (all diets); decreased haematocrit, mean corpuscular volume (basal and seaweed) and white blood cells count (all diets) were observed. High density‐exposed fish showed decreased plasmatic metabolites as well as the hepatic lipids content in basal and seaweed diets. Regarding oxidative stress, increased activity of glutathione S‐transferase in high density‐exposed fish muscle (all diets), and lower lipid peroxidation in liver (basal and β‐carotene) and intestine (basal and seaweed) were evidenced. Interactions between diet and stocking density were recorded regarding the triglycerides (decrease in fish exposed to high density fed with basal and seaweed) and hepatic lipids (decrease in fish exposed to high density fed with basal). The major changes occurred in haematologic and metabolic parameters as strategies to cope with overcrowding stress. Fish response to stocking density was not affected by diets.