The congenital portosystemic shunt in dogs and cats. I

An overview of the circulation of the liver and of the pathogenesis of hepatic encephalopathy as a result of portal vascular anomalies is given. Clinical signs associated with portal systemic shunts are described on the basis of 16 cases, 14 dogs and 2 cats. These animals ranged in age at the time of presentation from 4 months to 7 years. The predominant abnormality observed were central nervous signs, which differed in severity. 15 animals showed a reduction in liver size. The different techniques of contrast angiography allowing demonstration of a portal systemic shunt are presented along with a discussion of the pros and cons of each. Additionally the significance of making portal venous pressure measurements prior to each angiography is also explained. In most cases mesenteric portography was chosen. Based on their location the anomalies could be categorized as intrahepatic (4 dogs) or extrahepatic (10 dogs, 2 cats). In both groups breeds of various size are represented. The extrahepatic shunts could be further described as portal-caval (n = 5), portal-phrenic (n = 4) and portal-azygos (n = 3). In five of the older animals angiography showed in addition some hepatic perfusion by the portal vein. Laboratory evaluation revealed increased resting blood ammonia concentrations (greater than 200-912 micrograms/100 ml) in all animals. Seven dogs had definitely subnormal BUN concentrations (less than 10 mg%) and ten dogs low total plasmaprotein levels (less than 5.4 g%). Free amino acids (24) were determined in four dogs and a lowered hepatic encephalopathy index (less than 1.64) was found. Medical palliative therapy to control the clinical signs is discussed. The only effective long term therapy is, however, surgery. The shunt vessel is narrowed so that a greater volume of portal blood reaches the liver. Experience gained from the surgical therapy of 14 animals is presented. Ten of these survived well without requiring further therapy at a later time. Finally the etiology, prognosis, and differential diagnosis are summarized.     

Congenital portosystemic shunt in dogs and cats

An overview of the circulation of the liver and of the pathogenesis of hepatic encephalopathy as a result of portal vascular anomalies is given. Clinical signs associated with portal systemic shunts are described on the basis of 16 cases, 14 dogs and 2 cats. These animals ranged in age at the time of presentation from 4 months to 7 years. The predominant abnormality observed were central nervous signs, which differed in severity. The different techniques of contrast angiography allowing demonstration of a portal systemic shunt are presented along with a discussion of the pros and cons of each. Additionally the significance of making portal venous pressure measurements prior to each angiography is also explained. In most cases mesenteric portography was chosen. Based on their location the anomalies could be categorized as intrahepatic (4 dogs) or extrahepatic (10 dogs, 2 cats). In both groups breeds of various size are represented. The extrahepatic shunts could be further described as portal-caval (n = 5), portal-phrenic (n = 4) and portal-azygos (n = 3). In five of the older animals angiography showed in addition some hepatic perfusion by the portal vein. Laboratory evaluation revealed increased resting blood ammonia concentrations (greater than 200-912 micrograms/100 ml) in all animals. Seven dogs had definitely subnormal BUN concentrations (less than 10 mg%) and ten dogs low total plasma protein levels (less than 5.4 g%). Free amino acids (24) were determined in four dogs and a lowered hepatic encephalopathy index (less than 1.64) found. Medical palliative therapy to control the clinical signs is discussed. The only effective long term therapy is, however, surgery. The shunt vessel is narrowed so that a greater volume of portal blood reaches the liver. Experience gained from the surgical therapy of 14 animals is presented. Ten of these survived well without requiring further therapy at a later time. Finally the etiology, prognosis, and differential diagnosis are summarized.     

Compensatory Growth of Olive Flounder,Paralichthys olivaceus,Fed the Extruded Pellet with Different Feeding Regimes

This study was performed to determine compensatory growth of juvenile olive flounder fed the extruded pellet (EP) with different feeding regimes. Seven treatments with triplicates of different feeding regimes were prepared; α fish was daily fed for 6 d a week throughout 8 wk (8WF); α fish was starved for 1 wk and then fed for 3 wk twice [(1WS + 3WF) × 2]; β fish was starved for 2 wk and then fed for 6 wk (2WS + 6WF); χ fish was starved for 5 d and then fed for 9 d four times [(5DS + 9DF) × 4]; δ fish was starved for 10 d and then fed for 18 d twice [(10DS + 18DF) × 2]; δ fish was starved for 2 d, fed for 5 d, starved for 3 d, and then fed for 4 d four times [(2DS + 5DF + 3DS + 4DF) × 4]; and φ fish was starved for 4 d, fed for 10 d, starved for 6 d, and then fed for 8 d twice [(4DS + 10DF + 6DS + 8DF) × 2], respectively. Total feeding day was all same, 36 d except for control group (48 d). Weight gain of flounder in the 8WF treatment was higher than that of fish in other treatments. And weight gain of flounder in the 2WS + 6WF treatment was higher than that of fish in the (5DS + 9DF) × 4 and (4DS + 10DF + 6DS + 8DF) × 2 treatments. Feed consumption of flounder in the 8WF treatment was higher than that of fish experienced feed deprivation. Feed efficiency ratio (FER), protein efficiency ratio (PER), and protein retention (PR) were not significantly different among treatments. Chemical composition of the whole body of fish with and without liver, except for moisture content of liver, was not different among treatments. T₃ level of fish in the 8WF and 2WS + 6WF treatments was higher than that of fish in the (5DS + 9DF) × 4 treatment. It can be concluded that juvenile olive flounder achieved better compensatory growth at 6‐wk refeeding after 2‐wk feed deprivation compared with that of fish with different feeding regimes. And T₃ level of fish seemed to partially play an important role in achieving compensatory growth.     

The effectiveness of the combined treatment of thrombocytic hemorrhagic diathesis of dogs with prednisolone and blood transfusion in the model of an aspirin-produced thrombocytopathy

The administration of 20 mg/kg of acetylsalicylic acid in 18 clinically healthy dogs resulted in a thrombocytopathy with lengthened capillary bleeding time and irreversible aggregation inhibition. Through the set up of individual dilution series, one could conclude the proportional percentage of aggregation functional transfused thrombocytes. The capillary bleeding time was shortened after the intravenous injection of prednisolone (5 mg/kg) without measurable influence on the thrombocytes. Compared to the singular use of cortisone or blood transfusion alone, the effect on capillary bleeding time became magnified when one combined transfusion and corticosteroids. The fresh blood conserves (12 hours) were, with respect to the haemostyptical properties, superior to blood stored for 5 days. The component of aggregation-functional thrombocytes was, due to the prophylactic cortisone application prior to transfusion, not increased.     

Dynamics of Total Body Fatty Acids During Early Ontogeny of Pikeperch (<Emphasis Type="Italic">Sander lucioperca</Emphasis>) Larvae

The fatty acid composition of pikeperch (Sander lucioperca) was determined according to their physiological status, during starvation (10 days) and feeding (28 days). In starved larvae, polyunsaturated, monounsaturated and saturated fatty acids were utilized as metabolic substrates until day 9. At day 10, all fatty acid levels remained stable or, at least, increased in larval body. Among fatty acids, docosahexaenoic acid 22:6 n-3 was used preferentially (20.3% from total fatty acids utilized) followed by palmitoleic acid 16:1 n-7 (13.9%) and then by oleic 18:1 n-9 (12.3%), linoleic 18:2 n-6 (10.1%), linolenic 18:3 n-3 (9.7%) and eicosapentaenoic 20:5 n-3 (9.1%) acids. On the other hand, arachidonic acid 20:4 n-6 was utilized very lowly (0.3%). In fed larvae, no utilization of body fatty acids was observed during the experiment. It seems that energy requirements (and others) of fed larvae were satisfied by feed.     

Effect of Salinity on Larval Rearing of Pacu,Piaractus mesopotamicus,a Freshwater Species

The aim of this study was to evaluate the growth and survival of pacu, Piaractus mesopotamicus, larvae reared in different salinities and to determine the Artemia nauplii life span in freshwater and in saline water. First feeding 5‐d‐old pacu larvae were reared in freshwater or at 2, 4, 6, 8, 10, 12, and 14 ppt salinities. The larvae were reared in 1.5‐L aquaria at a density of 10 larvae/L with three replicates per treatment. After 10 d of rearing, significant differences (P < 0.05) were observed for growth and survival. Larval growth was higher at 2 and 4 ppt, and survival at 2 ppt was 100%. In freshwater and at 4, 6 and 8 ppt, the survival was 91.1, 93.3, 73.3, and 39.9%, respectively. At higher salinities, there was 100% mortality after 2 h (12 and 14 ppt) and 8 h (10 ppt) of exposure. The slightly saline water of at least 2 ppt increased the Artemia nauplii life span compared to the life span in freshwater. Later, in a second trial, 5‐d‐old pacu larvae were reared in freshwater and at 2 and 4 ppt salinities during the first 5 or 10 d of active feeding, and then the fish were transferred to freshwater. At the end of 15 d, larval growth was lower in freshwater (42 mg) than in treatments 2 and 4 ppt (59–63 mg). The abrupt transfer of fish from freshwater to slightly saline water and the return to freshwater did not affect the survival rates (89–97%). The larvae were able to adapt to these saline environments and handle abrupt changes in salt concentration. We concluded that salinity concentration of 2 ppt can be used for pacu larval rearing, allowing the Artemia nauplii lifetime to last longer and cause faster fish growth.     

Non-specific immune response of turbot,Scophthalmus maximus (L.), experimentally infected with a pathogenic Vibrio pelagius

The effect of a pathogenic Vibrio pelagius, isolated during a mass mortality of turbot larvae, on the non-specific immune response of turbot, Scophthalmus maximus (L.), macrophages was studied both in vitro and in vivo. The in vitro treatment of head kidney (HK) macrophages with viable V. pelagius caused a significant inhibition of the chemiluminescence (CL) response in comparison with untreated macrophages, while incubation with heat-killed bacteria did not affect this response. In vivo, the intraperitoneal injection of V. pelagius resulted in a significant inhibition of the CL response in infected fish at days 1 and 4 post-infection compared with the control fish response. The HK macrophage nitric oxide (NO) production was enhanced by in vitro incubation with intermediate doses of viable V. pelagius (5 x 10(3) and 5 x 10(4) bacteria mL(-1)) and higher doses of the heat-killed bacteria (5 x 10(4)-5 x 10(6) bacteria mL(-1)). In both cases, the NO inhibitor N-omega -nitro-L-arginine was capable of down-regulating the specific NO induction caused by incubation with the bacterial treatments. In contrast, incubation with ECPs at higher doses caused a reduction in NO production. In vivo, a significant enhancement in NO production was also observed in macrophage supernatants at day 10 post-infection. Lysozyme concentration in the serum was also significantly increased in the experimentally infected fish at days 4 and 10 post-injection. In addition, viable V. pelagius and its ECPs significantly reduced HK macrophage viability in vitro, whereas no significant differences in viability were observed during the incubation with heat-killed bacteria. As NO production was enhanced in the experimentally infected fish, the inhibitory effect of the NO donor, S-nitroso-acetyl-penicillamine (SNAP), was tested in vitro in a cell-free assay. The results showed that growth of V. pelagius was significantly inhibited using SNAP at a high concentration (1 mM).     

姜黄素对黄颡鱼(Pelteobagrus fulvidraco)生长、消化与抗氧化能力的影响

选取初始体重为(13.17±0.68) g、初始体长为(11.86±0.53) cm黄颡鱼(Pelteobagrus fulvidraco) 720尾,随机分为6组,每组3个重复,每个重复40尾鱼。分别投喂添加0、50、100、200、400、800 mg/kg姜黄素的实验饲料,分别标记为T1–T6。实验周期为60 d,实验结束后,测定黄颡鱼生长、消化和抗氧化能力指标。结果显示,各实验组特定增长率和存活率均显著高于对照组(P<0.05),T4组增重率和蛋白质效率显著高于对照组(P<0.05),T3、T4组饲料系数显著低于对照组(T1组) (P<0.05);T3、T4、T5组前肠脂肪酶活力显著高于对照组(P<0.05),T4组前肠淀粉酶活力显著高于对照组(P<0.05);T6组肝胰脏、T5组脑与T4组头肾超氧化物歧化酶(SOD)活力均较对照组有显著提升(P<0.05);脑实验各组丙二醛(MDA)含量均显著低于对照组(P<0.05);T6组肝胰脏、T5组脾脏过氧化氢酶(CAT)活力显著高于对照组(P<0.05);T4组肝胰脏、T5组脾脏、T5组中肾谷胱甘肽过氧化物酶(GSH-PX)活力显著提升(P<0.05);血清实验各组GSH-PX活力均显著高于对照组(P<0.05);肝胰脏实验各组谷胱甘肽(GSH)含量均显著高于对照组(P<0.05);T5组肝胰脏、T4组脾脏和血清一氧化氮(NO)含量显著高于对照组(P<0.05)。研究表明,在饲料中添加适量的姜黄素可以显著提高黄颡鱼的生长性能、消化能力以及抗氧化能力,以200 mg/kg添加量为最佳。     

Feeding,growth, and blood chemistry of the tambaqui (Colossoma macropomum) held under self-feeding and time-restricted automatic feeding conditions

This work evaluated the effects of food frequencies and self-feeding on the behavior, performance, and blood biochemistry of Colossoma macropomum. Juveniles weighing 3.63?±?0.05 g were distributed in 27 aquariums (40 L), with six fish per aquarium, to evaluate nine treatments in three replications in a 12L:12D photoperiod. The treatments were 24-h self-feeding (SF); daytime self-feeding at will (SFD); nighttime self-feeding at will (SFN); and feeding at fixed frequencies of two (2D), four (4D), and six times (6D) daytime and twice (2 N), four (4 N), and six times (6 N) nightly. The treatments were offered in automatic feeders, with fixed frequencies programmed. Extruded commercial feed, with 46% protein, was used. The experimental period was 40 days. In the SF treatment, the animals exhibited 95.7% nocturnal and 4.3% diurnal feeding activity (p?<?0.05). In the treatment SFD and SFN, the animals showed feeding activity throughout the day and night. Final weight, weight gain, and total feed intake were higher for animals at fixed daytime and nighttime frequencies (p?<?0.05). Feed conversion was better for animals in SF, SFD, 4D, SFN, and 4 N (0.89, 0.76, 0.91, 0.85, and 0.88, respectively) (p?<?0.05). Cholesterol and high-density lipoproteins were lower for fish in SF, SFN, 2 N, 4 N, and 6 N (p?<?0.05). SF treatment animals had lower triglyceride content, 154.20 mg dL^?1 (p?<?0.05). Colossoma macropomum has nocturnal food preferences, however, with remarkable plasticity. Juveniles of this species fed four times during the day or night show good performance. Dietary patterns influenced the blood metabolic indicators of this species and the periods studied.

     

蛋氨酸钴对珍珠龙胆石斑鱼幼鱼生长、矿物元素沉积及肝脏酶活力的影响

在基础饲料中添加不同梯度的蛋氨酸钴(Co Met),制成钴含量分别为0.30 mg/kg、1.75 mg/kg、3.42 mg/kg、6.73 mg/kg、12.56 mg/kg、25.50 mg/kg的6组实验饲料(记作D1、D2、D3、D4、D5、D6组),饲喂初始体重(60.02±0.42)g的珍珠龙胆石斑鱼(Epinephelus lanceolatu♂×E.fuscoguttatus♀)幼鱼8周,研究蛋氨酸钴对其生长、矿物元素沉积和肝脏酶活力的影响。结果表明,随饲料中蛋氨酸钴含量的增加,实验鱼增重率(WGR)和特定生长率(SGR)均先升后降,D3组显著高于其他组(P0.05);饲料系数(FCR)先降后升,D3、D4组显著低于其他组(P0.05)。蛋氨酸钴对肌肉水分和灰分含量均无显著影响(P0.05);粗蛋白含量呈降低的趋势,D5、D6组显著低于D1~D4组(P0.05),但二者之间无显著差异(P0.05);粗脂肪含量先降后升,D4组显著低于其他组(P0.05),D6组显著高于其他组(P0.05)。肝脏、肠道、脊椎骨及肌肉钴含量均随饲料中蛋氨酸钴的增加而显著增加(P0.05);全鱼钴沉积率呈先升高后平稳的趋势,D1组显著低于其他组(P0.05)。肝脏铁、铜和锌含量随饲料中蛋氨酸钴的增加呈先升后降的趋势;肝脏锰含量显著降低(P0.05)。随饲料中蛋氨酸钴的增加,肝脏谷胱甘肽过氧化物酶(GSH-PX)活力先升后降,D5组显著高于其他组(P0.05);D5、D6组肝脏丙二醛(MDA)含量显著低于其他组(P0.05);肝脏精氨酸酶(DArg)活力随饲料中蛋氨酸钴的增加显著升高(P0.05);D4~D6组肝脏羧肽酶A(CPA)活力显著高于D1~D3组(P0.05),但三组之间无显著差异(P0.05)。本实验条件下,以SGR为评价指标,经折线回归分析,珍珠龙胆石斑鱼幼鱼对钴的最适需求量为3.25 mg/kg,即53.28 mg(Co Met)/kg(饲料)。     

鲤脑垂体和HCG诱导雌性日本鳗鲡性腺成熟过程中血清生化成分的变化

使用鲤脑垂体和HCG对雌性日本鳗鲡人工催熟,用临床医学检验方法,测定分析了雌性日本鳗鲡卵巢发育过程中,血清总蛋白(TP)、血清甘油三脂(TG)、血清胆固醇(TC)、血糖(Glu)、血钙(Ca)和血清无机磷(P)6项生化指标的水平及变化趋势,并与对应的不同卵巢发育阶段的性腺成熟系数(GSI)进行比较分析。结果表明,84d的注射过程中,实验组的性腺逐渐成熟,GSI显著升高,第12针时达到46.32%±1.75%;而对照组性腺GSI一直在2.42%±0.18%。实验组和对照组血清TP水平相对平稳,各组变化无显著差异(P>0.05)。实验组和对照组血脂在56d前差异显著(P<0.05):实验组血清TG,TC一直维持较高水平,平均分别为(12.67±2.83)mmol/L和(15.54±3.01)mmol/L;对照组TG和TC一直下降且水平较低,平均分别为(6.33±4.14)mmol/L和(8.53±3.30)mmol/L。实验组和对照组血清Glu均在实验初的较低水平基础上持续上升。相关分析表明,实验组血清TG与GSI水平极显著负相关(r=0.732,n=6,P<0.01)。实验组血清Ca与GSI(r=0.961,n=6,P<0.01),血清P与GSI(r=0.775,n=6,P<0.01)都呈现出极显著的相关性:血清Ca和P在28d后持续上升,GSI逐渐增大。对照组中的血清Ca和P水平则一直维持在一个较低的水平。研究结果表明:雌性日本鳗鲡卵巢发育与其脂类代谢密切相关,无机离子(Ca,P)在此过程中起到重要作用。利用繁殖鱼体营养代谢特点,检测日本鳗鲡血脂或血清Ca和P水平,可成为初步判断雌性日本鳗鲡发育情况的新方法。     

Babesiosis of dogs in Germany: epidemiologic case analysis

Between January 1987 and February 1990 Babesia infections were detected in 320 dogs in Germany by means of microscopical and/or serological methods. It was found, that 316 dogs were infected with Babesia canis and 4 animals with Babesia gibsoni. Of the Babesia-canis-positive dogs 184 were abroad up to 4 months before diagnosis, mainly in France, Spain and Italy, but also in Hungary, Greece, Jugoslavia, Portugal, Morocco, Togo, Pakistan, Sri Lanka, Malaysia, Turkey, Romania, Austria and the Netherlands. For further 36 dogs the possible place of infection for Babesia canis could not be clarified geographically. 5 dogs each were simultaneously infested with Rhipicephalus sanguineus and Dermacentor reticulatus, respectively. The four dogs infected with Babesia gibsoni were previously in Sri Lanka (2), Brazil (1) or Algeria/Kenya (1). In 88 dogs from the Offenburg/Lahr/Freiburg area, which were not abroad, infections with Babesia canis were diagnosed from January to June as well as from September to December, however, most cases occurring in April and May. Of these dogs approximately 20% were found to be infested with Dermacentor reticulatus. These ticks were also collected on the vegetation in the Offenburg area. Therefore, an endemic focus of Babesia canis can be deduced in the area of Offenburg/Lahr/Freiburg and Dermacentor reticulatus as vector also in Germany.     

Changes of plasma steroid concentrations associated with spontaneous or induced ovulation in yellow perch Perca flavescens

This study examined the changes in plasma steroids during natural (Experiment 1) and induced (Experiment 2) final maturation in yellow perch Perca flavescens. In experiment 1, ovulating yellow perch were stripped of eggs and blood samples collected to determine the concentrations of testosterone (T), estradiol-17β (E2), and 17,20β-dihydroxy-4-pregnen-3-one (17,20βP). Eggs from individual females were weighed and fertilized. Fertilization rate was determined at the embryo eyed stage. In experiment 2, females were randomly assigned to one of the following treatment groups: (1) saline (0.7% NaCl), (2) des-Gly¹⁰[D-Ala⁶] LHRH-ethylamide (100 μg LHRHa/kg), and (3) LHRHa plus 17,20βP (100 μg LHRHa/kg + 2 mg 17,20βP/kg). Fish were injected intraperitoneally with two doses at a two-day interval. Blood was collected prior to injections and at the time of ovulation/spawning and concentrations of T, E2, and 17,20βP (free and conjugated) were determined. In experiment 1, low concentrations of 17,20βP were recorded at spawning. In experiment 2, all surviving fish injected with LHRHa (5 of 5) released their eggs spontaneously during the week following injections. None of the surviving control fish (0 of 5) ovulated during this period, whereas only 1 of 3 surviving fish injected with LHRHa + 17,20βP released eggs. In the control group, concentrations of E2 and 17,20βP did not show significant differences over the experimental period, whereas plasma T concentrations increased significantly. In fish injected with LHRHa, the concentrations of T and 17,20βP increased significantly after the first injection but then declined at ovulation/spawning. It also appears that 17,20βP was conjugated to its sulfated form. Mortality reached 62.5% in the group injected with LHRHa + 17,20βP indicating that this treatment was severe. Thus, LHRHa alone appears highly effective in inducing ovulation in yellow perch. This revised version was published online in July 2006 with corrections to the Cover Date.     

几种重要水产品活体运输技术研究

为研究虾苗运输中干露胁迫对克氏原螯虾(Procambarus clarkii)的影响,实验在(20±1) ℃和相对湿度 (relative humidity, RH) (50±5)% 的条件下,对不同干露时间(6 h、12 h、18 h和24 h)和再入水时长(1 h、6 h和12 h)幼虾的抗氧化应激能力和成活率进行了研究。结果显示,幼虾的干露时间不宜超过18 h,第24小时死亡率达到53.3%,入水阶段无幼虾死亡。干露阶段,总抗氧化能力(T-AOC)无显著变化(P>0.05);超氧化物歧化酶(SOD)活力显著降低;过氧化氢酶(CAT)活力随时间逐渐升高;丙二醛(MDA)质量摩尔浓度在干露第24 小时后达到峰值(P<0.05);血糖和肌肉乳酸浓度随干露时间显著升高(P<0.05)。再入水时,SOD和CAT呈波动性变化,无明显规律;入水12 h后MDA均恢复到对照组水平;T-AOC一直维持较高水平。6 h和12 h组入水1 h后乳酸即恢复到对照组水平,各处理组的血糖始终高于对照组(P<0.05)。研究表明,CAT和SOD对干露胁迫的反应更为敏感,可作为克氏原螯虾干露阶段的免疫指标。MDA、血糖和肌肉乳酸浓度可以反映幼虾再入水时的健康状况。

     

Interactions between dietary docosahexaenoic acid and other long-chain polyunsaturated fatty acids on performance and fatty acid retention in post-smolt Atlantic salmon (Salmo salar)

A study with varying dietary inclusion levels (1, 5, 10, 15 and 20 g kg^?1) of docosahexaenoic acid (DHA; 22:6n-3) was conducted with post-smolt (111 ± 2.6 g; mean ± S.) Atlantic salmon (Salmo salar) over a 9-week period. In addition to the series of DHA inclusion levels, the study included further diets that had DHA at 10 g kg^?1 in combination with either eicosapentaenoic acid (EPA; 20:5n-3) or arachidonic acid (ARA; 20:4n-6), both also included at 10 g kg^?1. An additional treatment with both EPA and DHA included at 5 g kg^?1 (total of 10 g kg^?1 long-chain polyunsaturated fatty acids, LC-PUFA) was also included. After a 9-week feeding period, fish were weighed, and carcass, blood and tissue samples collected. A minor improvement in growth was seen with increasing inclusion of DHA. However, the addition of EPA further improved growth response while addition of ARA had no effect on growth. As with most lipid studies, the fatty acid composition of the whole body lipids generally reflected that of the diets. However, there were notable exceptions to this, and these implicate some interactions among the different LC-PUFA in terms of the fatty acid biochemistry in this species. At very low inclusion levels, DHA retention was substantially higher (~250 %) than that at all other inclusion levels (31–58 %). The inclusion of EPA in the diet also had a positive effect on the retention efficiency of DHA. However, EPA retention was highly variable and at low DHA inclusion levels there was a net loss of EPA as this fatty acid was most likely elongated to produce DHA, consistent with increased DHA retention with additional EPA in the diet. Retention of DPA (22:5n-3) was high at low levels of DHA, but diminished with increasing DHA inclusion, similar to that seen with DHA retention. The addition of EPA to the diet resulted in a substantial increase in the efficiency of DPA retention; the inclusion of ARA had the opposite effect. Retention of ARA was unaffected by DHA inclusion, but the addition of either EPA or ARA to the diet resulted in a substantial reduction in the efficiency of ARA retention. No effects of dietary treatment were noted on the retention of either linolenic (18:3n-3) or linoleic (18:2n-6) acids. When the total n-3 LC-PUFA content of the diet was the same but consisted of either DHA alone or as a combination of EPA plus DHA, the performance effects were similar.     

Delayed Feeding of Channel Catfish Fry Stocked in Ponds

We compared production variables between channel catfish, Ictalurus punctatus, nursery ponds fed according to industry standards, that is feeding immediately at stocking, to an alternative practice of delaying feeding for 6 wk after stocking in an effort to utilize natural pond productivity and reduce feed use. Twelve 0.04 ha ponds were fertilized and stocked with swim‐up fry (4–5 d posthatch) at a rate of 10,000/pond (250,000/ha). Ponds were then randomly assigned to either the standard feeding protocol (feeding daily starting immediately at stocking) or an alternative feeding protocol (no feeding until 6 wk post‐stocking). After 18 wk of production, there were no differences in water quality or zooplankton abundance between the two treatments. Fish length was not affected by treatment throughout the study, and survival and total weight harvested were similar. Total kg of feed fed was significantly reduced in the delayed feed treatment, averaging 26 kg/pond less feed fed. If proper fertilization practices are implemented, large numbers of desirable zooplankton for catfish fry culture are attained, and these zooplankton are able to sustain catfish fry stocked up to 250,000/ha. Therefore, no commercial diets are required during the first 6 wk of culture, saving over $95.55/ha in initial feed costs.     

Transport and cryopreservation of sperm of the common snook, Centropomus undecimalis (Bloch)

Sperm were collected in Florida from wild common snook, Centropomus undecimalis (Bloch), and were shipped to Louisiana State University for analysis and cryopreservation. Threshold activation of sperm (10% motility) occurred at 370 mOsmol kg^?1, and complete activation occurred at 680 mOsmol kg^?1. These values were significantly different. Sperm samples stored at 1°C in Hanks' balanced salt solution (HBSS) or in 0.6% NaCl solution at 200 mOsmol kg^?1 retained motility for as long as 22 days. Mean motility remained above 50% for 9 days for sperm stored in HBSS and for 7 days for sperm stored in NaCl solution. Sperm exposed to 5% dimethyl acetamide (62±10%; mean±SD), 10% dimethyl sulphoxide (DMSO) (39±16%), 5% glycerol (26±5%) or 10% glycerol (6±2%) for 30 min had significantly lower motility than did unexposed sperm (89±9%). When used as a cryoprotectant, samples frozen with 5% or 10% DMSO or 5% methanol had significantly higher post‐thaw motility than did samples frozen with other cryoprotectants. Sperm cryopreserved with 10% DMSO (38±12%) had significantly higher post‐thaw motility than did sperm cryopreserved with 15% DMSO (19±10%) or 20% DMSO (4±4%). There were no significant differences in hatch rates of eggs fertilized with fresh sperm (54±29%) or cryopreserved sperm (41±35%). Survival to first feeding was not different between fish produced with fresh sperm (37±30%; range, 0–86%) or with thawed sperm (24±29%; 0–77%). Transport of sperm to a cryopreservation laboratory and back to a hatchery for thawing and use enabled collaboration between groups with specific expertise and provides a model for the application of cryopreservation by transport of fresh and frozen samples.     

Effect of phenolic nonprotein amino acid L-dopa (L-3,4-dihydroxyphenylalanine) on growth performance, metabolic rates and feed nutrient utilization of common carp (Cyprinus carpio L.)

Two experiments (I and II) were conducted to evaluate the effect of nonprotein phenolic amino acid, L ‐dopa (L ‐3,4‐dihydroxyphenylalanine) on growth, metabolism and feed assimilation of common carp. Six isonitrogenous and isoenergetic diets (diets 1–6 containing 0, 2.5, 7.0, 14, 28 and 56 g kg^–1L ‐dopa, respectively) were prepared by replacing wheat meal in the feed with L ‐dopa. For experiment I (8‐week duration), each treatment had two replicates with five fish each per replicate (mean initial body mass of 13.4 ± 1.0 g), whereas five groups of carp, each consisting of three fish, individually kept in respiration chambers, giving three replicates per treatment with a mean body mass of 25.0 ± 1.8 g were used for experiment II (4‐week duration). Fish were fed six times their maintenance ration daily (3.2 g feed kg^–0.8 day^–1). No fish died during either experiment. In experiment I, the growth rate, feed conversion ratio (FCR), protein efficiency ratio (PER) and apparent net protein utilization (ANPU) of carp fed diets 1, 2 and 3 were similar but they were significantly (P < 0.05) higher than those in dietary groups 4, 5 and 6. However, no significant differences were observed with regard to body composition (moisture, protein, lipid, ash and energy contents) between control (1) and the diets 2, 3, 4 and 5. Fish fed diet 6 had reduced lipid and energy contents (P < 0.05) when compared with other dietary groups. In experiment II, L ‐dopa significantly increased the oxygen consumption per unit body weight gain in treatments 4, 5 and 6. The average metabolic rate also tended to be higher in these groups. The energy expenditure was similar in treatment groups, but the energy retention was significantly lower and energy dissipated significantly higher in dietary groups 4, 5 and 6. The cholesterol level in blood plasma between the control and L ‐dopa containing diets was not significantly different. It may be concluded that at higher inclusion rates (>7 g kg^–1) L ‐dopa appears to be a major antinutrient and hence the protein sources of plant origin, containing high amounts of L ‐dopa (i.e. mucuna beans) should be used with caution as fish meal substitutes in carp diets.     

A Comparison of Immersion, Immersion/Oral Combination and Injection Methods for the Vaccination of Channel Catfish Ictalurus punctatus Against Edwardsiella ictaluri

Abstract.— Four different vaccination regimes, including non-vaccinated controls (C), immersion/oral combination (IO). late immersion (LI), and injection (IJ), were evaluated for antibody production and protection from challenge in channel catfish Ictalurus punctatus that were hatched and raised in recirculating culture systems over a 28-wk period. For IO, fry were vaccinated by immersion on day 12 post-hatch and given an oral booster during week 10 post-hatch. The LI and IJ delivered vaccine was also administered at week 10 post-hatch. No titers were detected in the IO group prior to the oral booster at week 10. Mean titers rose sharply after the week 10 vaccinations in all treatment groups, maintained a high level for about 8 wk, and slowly declined over the next 4 wk. Injected fish had significantly higher titers during the primary response period than either LI or IO fish. There was no statistical difference in titers between LI and IO fish during the primary response. After an oral booster delivered during week 22, titers in LI and IO fish increased significantly at week 25, while titers in IJ fish declined despite the booster delivery. An immersion booster delivered during week 25 resulted in significant increases in titers in all vaccinated groups. Of multiple challenges, the only one not marred by concurrent columnaris infections revealed a low, but significant level of protection in IJ fish at 12 wk post-vaccination.     

温度胁迫对皱纹盘鲍生理和生化活动的影响

为探讨温度胁迫下皱纹盘鲍(Haliotis discus hannai Ino)的响应机制,采用室内控温实验,通过设置4个温度梯度(5℃、10℃、20℃和25℃),设计温度骤变处理组(皱纹盘鲍从15℃暂养温度直接转移至各实验温度)和温度缓变处理组(0.5℃/12 h),分析温度剧烈变化和温度缓慢变化对皱纹盘鲍耗氧率和排氨率的影响及其差异性;并对高温和低温处理下皱纹盘鲍消化腺中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、酸性磷酸酶(ACP)和溶菌酶(LSZ)活性的变化情况以及不同组织(血细胞和肌肉组织)中Cu/Zn–SOD基因的表达状况进行了研究。结果表明,皱纹盘鲍耗氧率和排氨率随海水温度的升高而增加,20℃达到最高值;25℃骤变处理组与缓变处理组耗氧率和排氨率间存在极显著差异(P0.01)。5℃和10℃骤变处理组皱纹盘鲍氧氮比(O/N)同缓变处理组间存在极显著差异(P0.01)。在高温胁迫后的3 h,消化腺中SOD、CAT和LSZ活性达到最高,而ACP活性在胁迫6 h后达到最高(P0.01);低温胁迫显著降低皱纹盘鲍LSZ的活性,于胁迫9 h后达到最低(P0.01)。不同温度胁迫下,皱纹盘鲍血细胞和肌肉组织中Cu/Zn–SOD基因的相对表达量均表现上调,与对照组存在显著差异性(P0.05)。本研究表明,温度胁迫能显著影响皱纹盘鲍的生理和生化活动,这将有助于探讨皱纹盘鲍夏季高死亡率的原因,为皱纹盘鲍健康养殖提供一定的理论依据。