甲鱼几种常见病的防治

一、腐皮病。甲鱼受损伤后,四肢、颈部、尾部及周边皮肤糜烂、组织变白、发黄、坏死,严重时骨骼外露,爪脱落。 防治:①控制甲鱼饲养密度,及时分养,经常更换池水。②每周用1×10~(-6)～2×10~(-6)漂白粉全池泼洒消毒。③及时隔离病甲鱼,用2×10~(-6)～3×10~(-6)生石灰或漂白粉反复药浴5～6天,确认痊愈后,放回原池饲养。④用鳖速康20×10~(-6)～40×10~(-6)全池泼洒,每     

鸡呼吸道疾病的发生及其诊断与防治原则

鸡呼吸系统是鸡体最重要的系统之一,也是最容易受病原微生物入侵的一个门户。由于家禽呼吸系统的结构特征,病原一旦侵入,极易引起体内多个器官组织的感染。呼吸道疾病是鸡的一种很常见的疾病,凡能引起呼吸系统功能和结构改变为主要表现形式的疾病均可纳入呼吸道病的范畴,如鸡新城疫(ND)、传染性支气管炎(IB)、传染性喉气管炎(ILT)、白喉型鸡痘(FP)、鼻气管炎、大肠杆菌病、传染性鼻炎、霉浆体病、曲霉菌病等,故又称为呼吸道病综合征(respiratorydiseasecomplex,RDC)。而如高温、潮湿、通风不良等环境因素,以及如遗传特征、免疫反应和营养状况等一些内部因素,均能诱发和加重病情。呼吸道病综合征引起鸡群死亡率升高和生产性能下降,以及药物和疫苗费用增多,给养鸡业造成极大的经济损失。为有效地控制RDC,重要的是要有良好的卫生和科学的管理,正确的生物安全性措施以及有效的疫苗免疫接种。     

南美白对虾10种常见病害防治新法

红体病(又称桃拉综合症) 病因:由桃拉病毒感染引起。症状:病虾不摄食,肝胰脏肿大、变白,虾体变红,尤其尾部更为明显。幼虾一般急性死亡,成虾呈慢性死亡。防治方法:1)用0.2～0.3克/米~3二溴海因全池连续泼洒2天,隔2天再全池泼洒清水素(枯草杆菌)0.2克/米~3、光合细菌2克/米~3和沸石粉20克/米~3;2)每千克饲料中添加免疫多糖2克、红体消15克、EM原露3克,连续内服5～6天。     

罗氏沼虾常见病及其防治技术

罗氏沼虾是近年比较受欢迎的特种水产养殖品种之一。与其它特种水产养殖品种(如甲鱼、鳗鲡、河蟹等 )相比 ,有关罗氏沼虾病的报道要少得多 (何筱洁等 ,1 997;孙玉华等 ,1 998;蔡完其等 ,1 996) ,这从一个侧面反映了罗氏沼虾抗病能力较强。但任何一个养殖品种不可能没有病 ,本文     

专题讲座河蟹的主要疾病及其防治

专题讲座河蟹的主要疾病及其防治杨先乐(农业部水产增养殖生态、生理重点开放实验室，上海水产大学，上海200090)蟹奴病症状及危害蟹奴是专门寄生于河蟹腹部(胸板)或附肢上的一种寄生虫，长约2~5mm、厚约1mm，体扁平、圆枣状，乳白色或半透明，属甲壳动...     

龟的疾病及其防治

15.蜱螨病由蜱螨寄生于龟体表而引起。主要寄生于龟体表柔软部分如眼、鼻、脚趾间及肛门附近 ,会使龟出现身体不适 ,烦躁不安等症状。主要流行于春、夏、秋季 ,以加温养殖场多见 ,一般不会造成较大的危害。预防 :注意环境卫生 ,不能将龟与其它多毛类动物混养在一起。治疗 :用 75%的酒精涂抹患处 ,如若眼部被蜱螨感染 ,可用水冲洗或滴入刺激性较小的眼药水 ,如氯霉素 ,磺胺等。16 .水蛭病病原主要有金钱蛭 (Whitmania sp.)、绿拟扁蛭 (H emiclepsis margin )、蛙盾蛭 (Placobdellaokadai )、润饰盾蛭 (P.ornata )等。它们主要寄生于龟体皮…     

四种鲤鱼对柱形病抗病能力的差异

采用半致死浓度法,对4种鲤(东平湖鲤、建鲤、俄罗斯鲤及德国镜鲤)对柱状黄杆菌引起的柱形病(即烂鳃病)的抗病力进行了试验研究,分别采用1×104、2×104、4×104、8×104、1.6×105 cfu/mL浓度的柱状黄杆菌G4菌株菌液浸泡攻毒1h,参考Reed-Muench法计算半致死浓度(LC50)。结果表明,东平湖鲤LC50为104.7174 cfu/mL;建鲤LC50为104.6821 cfu/mL;俄罗斯鲤LC50为104.6414cfu/mL;镜鲤LC50为104.5694 cfu/mL,表明不同品种鲤鱼对柱形病的抗病能力存在差异,四种鲤抗病力大小依次为东平湖鲤建鲤俄罗斯鲤镜鲤,其中东平湖鲤和建鲤无显著差异,二者和镜鲤的差异极显著(P0.01)。     

中国对虾红腿病致病菌的研究

本文对中国对虾(Penaeus orientalis Kishinouye)“红腿病”的病原菌分离、培养、菌种鉴定、人工感染、药敏试验等进行了试验研究,确认引起中国对虾“红腿病”不是单一的菌,不仅有海产弧菌(Vibrio marinus),而且还有产碱假单胞菌和类产碱假单胞菌(Pseudomonas pseudoalcaligenes)、反硝化产碱菌反硝化亚种(Alcaligenesdenitrificans Subsp·denitrifi—cans)、争论产碱菌(Alcaligenes Paradoxus)。     

日本对虾的一种弧菌病

<正> 弧菌病是世界对虾养殖中流行较广、危害最大的一类虾病。对虾弧菌病的病原,在日本、美国和英国已分离出的有溶藻酸弧菌(Vibrioalginolyticu-s)、鳗弧菌(V.anguillarum)和拟溶血弧菌(V.parahaemolyticus)三种。1983年,日本又弄清了由一种弧菌(Vibrio sp)引起的疾病。这种病的有些病症与我国近年来对虾发病时的一些病症有相似之处,现据日本资料(养殖,第21卷10号临时增刊)作为介绍,以引起我国养虾工作者的重视,以作进一步的研究。     

暗纹东方鲀常见病的防治

我们在暗纹东方的工厂化养殖过程中,发现其较易感染小瓜虫病、刺激隐鞭虫病及肠炎、烂鳃、营养不良等症,对上述疾病的病因、症状及防治方法做如下介绍,供广大养殖工作者参考。1小瓜虫病病因小瓜虫寄生引起。症状肉眼可见鳃、鳍、体表布满白点状囊孢,镜检虫体呈椭圆形,有纤毛,中间有“马蹄形”核。治疗方法(1)百虫净全池泼洒,使用浓度为0.15克/米3,效果显著。(2)用硫酸铜、硫酸亚铁(5∶2)混合溶液0.7克/米3全池泼洒,效果显著。2指环虫病病因指环虫寄生在鱼的鳃丝上而引发此病。症状鱼鳃丝粘液增多,全部或部分呈苍白色,呼吸困难,游动缓慢。治…     

Synthesis of 17,20α- and 17,20β-dihydroxy-4-pregnen-3-ones, 11-ketotestosterone and their conjugates by gills of teleost fish

Goldfish, carp and trout gills were incubated with ³H-17-hydroxyprogesterone (17P). With goldfish gills, the metabolites were 17,20-dihydroxy-4-pregnen-3-one (17,20P; 82%), 17,20-dihydroxy-4-pregnen-3-one (17,20P; 8%), 11-ketotestosterone (KT) glucuronide (5.4%) and 17,20P glucuronide (0.2%). Sulfates were not detected. Carp gills converted 17P into 17,20P (11.2%), 17,20P (9.6%), KT (8.4%), glucuronides of 17,20P (1.3%) and 17,20P (1.6%) and sulfates of 17,20P (5.1%) and 17,20P (7.2%). 17,20P (38% free, 1.8% glucuronide and 21.1% sulfate) was the sole metabolite of ³H-17P in trout gill incubations. In the presence of high (10; µg ml^-1) substrate concentration, cyprinid gills gave predominantly free 17,20P, while trout gills yielded only free 17,20P. Production of 17,20P, predominantly as its sulfate, from endogenous precursors was demonstrated in trout gills but was not stimulated by trout primary extract. Our results demonstrate for the first time the steroidogenic potential of teleost gills and suggest that they may play a role in secretion of pheromones in some species.     

Effects of steroid hormones on immunoglobulin M (IgM) in rainbow trout, Oncorhynchus mykiss

The immunosuppressive effects of steroid hormones were evaluated as the response against implanted steroid hormones, cortisol (F), testosterone (T), estradiol-17 (E2), and 11- ketotestosterone (11-KT), in juvenile rainbow trout. In long term experiments (5 weeks), fish were given a single intraperitoneal implant of F or T. A clear suppressive effect of plasma IgM levels with F and T was not necessarily obtained, although mucus IgM levels were reduced corresponding to the elevated plasma steroid hormone levels. In short term experiments (1 week), intraperitoneal implantation of T, 11-KT and E2 suppressed plasma and mucus IgM levels, although the effects were not dose-dependent. When administered through diet, F and T caused a suppression of plasma IgM levels; F administration at both high and low dosages caused a significant decrease in plasma IgM levels, while only a high dose of T caused the suppression. These results suggest that sex steroid hormones, as well as F, have immunosuppressive functions in rainbow trout.     

17α,20β,21-trihydroxy-4-pregnen-3-one and 17α,20β-dihydroxy-4-pregnen-3-one stimulated spermiation in protandrous black porgy, Acanthopagrus schlegeli

The objective of this study was to investigate the effects of sex steroids on spermiation in protandrous male black porgy, Acanthopagrus schlegeli. Experiments on common carp (Cyprinus carpio) were also conducted for comparison. Fifty male black porgy were divided into 5 groups and injected with a superactive analogue of mammalian luteinizing hormone releasing hormone (LHRH-A), 17,20,21-trihydroxy-4-pregnen-3-one (20-S), 17,20-dihydroxy-4-pregnen-3-one (17,20-DHP), 11-ketotestosterone (11-KT) or saline. The dosage of the sex steroids given on days 0, 2, 4 and 6 was 330, 330, 990 and 1980 µg kg^-1 body weight, respectively. Milt volume and sperm concentrations were measured on days 0, 2, 4, 6, 8 and 10. Similar treatments were also conducted in 45 male common carp. Milt volume was significantly increased in black porgy after treatment with 20-S and 17,20-DHP; 17,20-DHP had stimulatory effects on spermiation at a lower dose (900 µg kg^-1 body weight, p < 0.05) as compared to 20-S (1980 µg kg^-1 body weight, p < 0.01). In the common carp, milt volume was also increased after treatment with LHRH-A and 17,20-DHP but not with 20-S. 17,20-DHP stimulated spermiation at a lower dose in common carp (330 µg kg^-1 body weight) than in black porgy (990 µg kg^-1 body weight). However, 11-KT did not stimulate spermiation in black porgy or common carp. The concentrations of plasma 11-KT could immediately reflect to the administration of exogenous 11-KT in black porgy.     

Hormonal changes during meiotic maturation and ovulation in the brook trout (Salvelinus fontinalis)

The plasma levels of estradiol-17 (E2), 17, 20-dihydroxy-4-pregnen-3-one (17,20-P) and gonadotropin (GTH) were measured in brook trout (Salvelinus fontinalis) during the period from the end of vitellogenesis to postovulation. Blood samples were taken according to specific stages of maturation, including germinal vesicle breakdown (GVBD) and ovulation. E2 levels were quite high (45 ng/ml) at the end of vitellogenesis (and prior to GVBD) and dropped precipitously by GVBD (2 ng/ml). They remained low through ovulation and postovulation. 17,20-P levels were low prior to GVBD (0.7 ng/ml) and increased dramatically at GVBD (148 ng/ml). The levels of 17,20-P remained high at ovulation (142 ng/ml) and then dropped significantly within 24 h to approximately half of the ovulatory values. They decreased even further by 7 days postovulation. GTH levels rose gradually through GVBD and ovulation from a postvitellogenic level of approximately 3 ng/ml to a 7 day postovulatory value of approximately 10 ng/ml. The overall results; 1) decrease in estradiol prior to GVBD, 2) increase in 17,20-P at GVBD and 3) gradual GTH rise through GVBD and ovulation, are similar to those reported for other salmonids.     

Effects of dietary borage oil [enriched in γ-linolenic acid,18:3(n-6)] or marine fish oil [enriched in eicosapentaenoic acid,20:5(n-3)] on growth,mortalities, liver histopathology and lipid composition of juvenile turbot (Scophthalmus maximus)

A marine fish oil, Marinol K (MO) and borage oil (BO) were used to formulate diets relatively rich in eicosapentaenoic acid [EPA; 20:5(n-3)] and -linolenic acid [GLA; 18:3(n-6)], respectively. The diets were fed to duplicate groups of juvenile turbot (Scophthalmus maximus) of initial weight 1.4 g for a period of 12 weeks. No differences were observed in final weights either between duplicate tanks or between dietary treatments. Mortalities in the MO-fed group were significantly greater than in the BO-fed group. In the MO-fed group, 7 out of 12 fish sampled for histological analysis showed a pronounced liver histopathology whereas only 1 of 12 fish sampled in the BO-fed group showed slight pathology. EPA levels were increased 2.2-fold and its elongation product, 22:5(n-3), was increased 1.8-fold while arachidonic acid [AA; 20:4(n-6)] was decreased by 30% in MO-fed fish compared to the initial carcass composition. GLA was increased 53-fold and its elongation product dihomo--linolenic acid [DHGLA; 20:3(n-6)] was increased 16-fold while AA was reduced by 90% in BO-fed fish compared to the initial carcass composition. The amount of triacylglycerol in liver of BO-fed fish was significantly greater than levels in MO-fed fish. The fatty acid compositions of individual phospholipids from liver showed marked differences between dietary treatments. Fish fed MO had significantly higher levels of the (n-3) polyunsaturated fatty acids (PUFA), 20:5(n-3), 22:5(n-3) and 22:6(n-3), and also significantly more 20:4(n-6) compared to BO-fed fish which had significantly higher 18:2(n-6), 18:3(n-6), 20:2(n-6) and 20:3(n-6). The composition of liver phosphatidylinositol was particularly unusual in BO-fed fish having DHGLA as the major C₂₀ PUFA which was 2.2-fold greater than AA and 3.9-fold greater than EPA. This study demonstrates that the carcass composition of turbot can be altered, by means of dietary lipids, to contain increased levels of EPA and DHGLA which would be of potential benefit in human as well as in fish nutrition. However, caution should be exercised when using very highly unsaturated oils relatively rich in EPA which may generate histopathological lesions in the fish.Abbreviations AA arachidonic acid - ANOVA analysis of variance - BHT butylated hydroxytoluene - BO borage oil - DHA docosahexaenoic acid - DHGLA dihomo--linolenic acid - EPA eicosapentaenoic acid - GLA -linolenic acid - HPTLC high performance thin-layer chromatography - MO Marinol K - PC phosphatidylcholine - PE phosphatidylethanolamine - PI phosphatidylinositol - PS phosphatidylserine - PUFA polyunsaturated fatty acid - TLC thin-layer chromatography     

The effect of migration distance and timing on metabolic enzyme activity in an anadromous clupeid, the American shad (Alosa sapidissima)

The American shad (Alosa sapidissima) is a common anadromous fish species with ecological and economic importance on the east coast of North America. This iteroparous species undergoes an energetically costly upriver spawning migration in spring. To evaluate metabolic changes associated with this migration, we assessed the maximum activity of five metabolic enzymes (citrate synthase (CS), phosphofructokinase (PFK), lactate dehydrogenase (LDH), -hydroxyacyl coenzyme A dehydrogenase (HOAD), alanine aminotransferase (GPT)) in liver, red muscle and white muscle during upstream migration in two successive years in the Connecticut River. For aerobic capacity (CS), glycolytic capacity (LDH) and utilization of stored lipid and protein energy (HOAD and GPT), there is a general pattern of increasing activity with a subsequent decline at the most upriver sites. Red muscle CS activity increased by as much as 40% during the migration while white muscle CS activity was 120% higher in the river than in the ocean. In contrast, muscle anaerobic capacity, indicated by PFK, was low as fish entered the river and then increased 5-fold at the most upriver sites. White muscle HOAD increased 30% while red muscle HOAD and muscle GPT increased as much as 60%. There were interannual and sex-associated differences in enzyme activity during upstream migration and through time at a single location. In some cases interannual differences can be larger than those seen during upriver migration as in the case of red muscle CS where sampling years differed by 125%. These interannual differences may be a result of differing river conditions that affect migratory effort. We have demonstrated that American shad use tissue and sex-specific regulation of enzyme activity during migration and we suggest that American shad metabolically acclimate to upstream migration.     

In vitro steroidogenesis by testicular fragments and ovarian follicles in a hybrid sturgeon, Bester

In this study, developmental changes in the steroidogenic capacity of testicular fragments and isolated ovarian follicles of a hybrid sturgeon, Bester, at a variety stage of developments were examined. Testicular fragments or isolated ovarian follicles were incubated in L-15 medium in the presence or absence of different concentrations of five preparations; forskolin, human chorionic gonadotropin (HCG), pregnenolone (P₅), 17-hydroxyprogesterone (17OHP) and testosterone (T) for 18 h at 15 °C. After incubation, concentrations of 11-ketotestosterone (11 KT) (testis) and, 17-estradiol (E₂) (ovarian follicles) and 17,20-dihydroxy-4-pregnen-3-one (DHP) (testis and ovarian follicles) were measured. 11KT was detected in the media following incubation with P₅, 17OHP and T. Its concentration was higher during late spermatogenesis and prespermiation and lower at the degeneration stage. Both P₅ and 17OHP were converted to DHP during the prespermiation stage. Forskolin had little stimulatory effect on the synthesis of 11KT and DHP and HCG did not induce the production of these steroids.E₂ was detected in the medium following incubation of follicles with P₅, 17OHP and T at all stages of oocyte development. The concentration of E₂ in the medium increased during vitellogenesis with the peak production occurring at the tertiary yolk stage. In contrast, the potencies of follicles to produce steroids shifted to the production of DHP during migratory nucleus stage. Forskolin and HCG had little effect on the synthesis of E₂ and DHP. These results demonstrated that the failure of spontaneous spermiation or ovulation is not due to the insufficient synthesis of DHP, but may due to the lack of availability of precursors.     

Effects of melatonin,p-chlorophenylalanine,and α-methylparatyrosine on plasma gonadotropin level and ovarian activity in the catfish,Heteropneustes fossilis: A study correlating changes in hypothalamic monoamines

The effects of (ip, 10 injections over 20 days) of melatonin (75 g 100 g^–1 BW), the serotonin (5-HT)-synthesis blocker, para-cholorophenylalanine (p-CPA, 10 mg 100g^{–1 BW}) and the catecholamine-synthesis blocker, -methylparatyrosine (-MPT, 10 mg 100 g^–1 BW) on gonadotropin (GTH) secretion and ovarian activity were studied in ^{Heteropneustes fossilis} during late preparatory to early prespawning (April–May). The treatments resulted in significant reductions of plasma GTH and estradiol-17 levels, the gonadosomatic index, frequency distribution of vitellogenic and postvitellogenic oocytes, and ovarian and serum ³²p-labelled alkali-labile phosphoprotein (a marker of vitellogenic activity). Most of the oocytes were nonvitellogenic or had undergone atretic changes. The hepatic ³²-phosphoprotein content increased significantly over the saline control value. The effects were similar and pronounced in the p-CPA and melatonin-treated groups but were moderate in the -MPT-treated group. Hypothalamic 5-HT content and turnover were significantly inhibited in the p-CPA and melatonin-treated groups but the content and turnover of catecholamines were not. The -MPT treatment decreased significantly the content and turnover of dopamine (DA), noradrenaline (NA), and adrenaline (A) but did not influence the 5-HT content or turnover. These results suggest that 5-HT, NA and A are stimulatory to GTH secretion and that melatonin may act on the serotonergic system to inhibit the pituitary-gonadal axis.to whom correspondence should be addressed.A part of the results was presented at the International Workshop on Pineal gland: Its molecular signals and published as an abstract in Neuroendocrinol. Lett. 14: 399 pp., 1992.     

Oxidative metabolism in a teleost,Anabas testudineus Bloch: effect of testosterone and estradiol-17β on hepatic enzyme activities

Testosterone (T) administration to maleAnabas testudineus significantly stimulated the activities of cytochrome oxidase, -glycerophosphate dehydrogenase (-GPDH) and Mg²⁺ adenosine triphosphatase (Mg²⁺ ATPase) and inhibited lactate dehydrogenase (LDH), cytosolic and mitochondrial malate dehydrogenases (MDH). The activities of succinate dehydrogenase (SDH), glucose-6-phosphate dehydrogenase (G-6-PDH) and catalase were unaffected by testosterone treatment. Administration of estradiol-17 (E2) in female fish, significantly stimulated cytochrome oxidase activity, inhibited Mg²⁺ ATPase, SDH, catalase and cytosolic and mitochondrial MDH activity, and was without effect on other enzymes studied.The simultaneous injections of actinomycin D or chloramphenicol and T or E2 prevented the hormonal influence on hepatic enzyme activities. The present study demonstrates that inA. testudineus sex steroids influence hepatic oxidative metabolism by a mechanism sensitive to the action of inhibitors of protein synthesis.