Communications: Efficacy of Norfloxacin for the Control of Edwardsiella tarda Infection in the Flounder Paralichthys olivaceus

Abstract

Efficacy of norfloxacin was evaluated in laboratory and field studies for control of Edwardsiella tarda infection in the flounder Paralichthys olivaceus. In disc diffusion tests, five E. tarda strains showed high sensitivity to norfloxacin. Minimum inhibitory concentrations of norfloxacin against the five isolates were approximately 0.016–0.031 μg/mL. In laboratory studies in which flounder were challenged with E. tarda, a significant (P < 0.05) reduction in mortality was observed among fish receiving norfloxacin in feed at 100 mg/kg body weight (or more) daily for 3 d compared with mortality among nonmedicated controls. Similar results were achieved when 100 mg norfloxacin/kg body weight was used in field trials.     

牙鲆营养需要的研究

<正>牙鲆(Paralichthys olivaceus)是鲽形目中的一种底栖肉食性鱼类,以其肉质细嫩、味道鲜美、营养丰富而深受人们的喜爱,市场需求旺盛,经济价值较高。但由于高效优质的人工配合饲料尚未真正开发出来,投喂鲜活饵料,造成水质污染,病害日趋严重,从而影响了牙鲆养殖业的规模发展和经济效益的提高。为了改变这一现状,本文对牙鲆的营养需要进行了研究,现将研究结果报道如下,为配制牙鲆配合饲料提供参考。     

牙鲆营养需要量的研究进展

牙鲆属鲽形目 ,鲽亚目 ,鲆科 ,牙鲆属 ,是鲽形目中一种底栖肉食性鱼类 ,我国仅有牙鲆一种 ,沿海均产之 ,黄海、渤海产量较多 ,由于其肉质嫩、味道鲜美、营养丰富 ,深受人们喜爱 ,市场需求旺盛 ,经济价值较高 (张辉等 ,1 998;李爱杰等 ,2 0 0 1 ;魏万全等 ,2 0 0 1 ) ,成为海产鱼类中重要的捕捞对象。与此同时 ,诸多不利因素如环境污染、病害频发等严重制约着其发展。另外 ,牙鲆营养特别是仔稚鱼的营养与饲料问题较突出 ,高效优质的人工配合饵料还没有开发出来 ,很多养殖单位育苗时不得不依靠进口饲料。我们将牙鲆对蛋白质、脂类和维生素等物…     

牙鲆致病性迟钝爱德华菌毒力基因的检测及序列分析

为探讨牙鲆致病性迟钝爱德华菌毒力基因携带与分布,以毒力基因为分子靶标研究其致病机理及建立快速检测方法,根据 GenBank 上的基因序列,设计2对引物扩增致病性迟钝爱德华菌毒力基因 fimA和小肠结肠炎耶尔森菌毒力基因 irp2,结果在7个供试牙鲆病例的130株致病性迟钝爱德华菌中,irp2毒力基因的阳性率为46．15％（60／130）,fimA 毒力基因的阳性率为100％,且均与已发表的参考菌株相应序列高度同源,同源性分别为97．32％和97．59％。可见耶尔森菌强毒力岛（HPI）在牙鲆致病性迟钝爱德华菌中广泛分布,但不同病例分离菌株间存在差异;fimA 毒力基因存在于所有的被检致病性迟钝爱德华菌中,可以作为快速检测致病性迟钝爱德华菌的标志物。     

Pharmacokinetics of amoxicillin trihydrate in cultured olive flounder (Paralichthys olivaceus)

The study was aimed at investigating the pharmacokinetics of amoxicillin trihydrate (AMOX) in olive flounder (Paralichthys olivaceus) following oral, intramuscular, and intravenous administration, using high‐performance liquid chromatography following. The maximum plasma concentration (C_max), following oral administration of 40 and 80 mg/kg body weight (b.w.), AMOX was 1.14 (T_max, 1.7 h) and 0.76 μg/mL (T_max, 1.6 h), respectively. Intramuscular administration of 30 and 60 mg/kg of AMOX resulted in C_max values of 4 and 4.3 μg/mL, respectively, with the corresponding T_max values of 29 and 38 h. Intravenous administration of 6 mg/kg AMOX resulted in a C_max of 9 μg/mL 2 h after administration. Following oral administration of 40 and 80 mg/kg AMOX, area under the curve (AUC) values were 52.257 and 41.219 μg/mL·h, respectively. Intramuscular 30 and 60 mg/kg doses resulted in AUC values of 370.274 and 453.655 μg/mL·h, respectively, while the AUC following intravenous administration was 86.274 μg/mL·h. AMOX bioavailability was calculated to be 9% and 3.6% following oral administration of 40 and 80 mg/kg, respectively, and the corresponding values following intramuscular administration were 86% and 53%. In conclusion, this study demonstrated high bioavailability of AMOX following oral administration in olive flounder.     

Pharmacokinetics of difloxacin in olive flounder Paralichthys olivaceus at two water temperatures

In this study, the pharmacokinetics profiles of difloxacin in the olive flounder (Paralichthys olivaceus) were investigated following intravenous and oral administration (10 mg/kg BW) at 14 and 22 °C water temperatures. Plasma and tissue samples (muscle, liver, and kidney) were analyzed using an HPLC method. The results showed that the plasma concentration–time data for difloxacin were described commendably by two‐compartment open model at the two water temperatures. The absorption half‐life (t_1/2ka) of difloxacin after oral administration were 2.08 and 1.10 h at 14 and 22 °C, respectively; whereas the elimination half‐life (t_1/2β) was 4.41 and 2.38 h, respectively. The muscle concentration of 1.35 ± 0.19 μg/g was observed at 9 h at 14 °C, and 2.11 ± 0.33 μg/g at 6 h at 22 °C, respectively. For liver, the peak concentration of difloxacin 2.43 ± 0.30 μg/g occurred at 6 h at 14 °C, which was lower than the 3.34 ± 0.24 μg/g peak that occurred at 4 h at 22 °C. The calculated bioavailability of difloxacin was 68.07% at 22 °C, which was higher than the 53.43% calculated for 14 °C. After intravenous administration, the t_1/2β were 4.79 and 2.81 h at 14 and 22 °C, respectively. The results indicate that the peak concentrations in muscle and liver at 14 °C are approximately half of those achieved at 22 °C. However, the C_max in kidney at 14 and 22 °C were similar. The V_d values were 1.20 and 1.75 L/kg at 14 and 22 °C, respectively. These data indicated that both temperature and drug administration had significant effects on the elimination of difloxacin, and lower temperature or oral administration resulted in lower elimination.     

不同氨基酸包被方法对牙鲆生长及血浆生化指标的影响

本试验比较研究了晶体氨基酸(CAA)和不同壁材包被的CAA对牙鲆(Paralichthys Olivaceus)摄食、生长及血浆生化指标的影响。以大豆浓缩蛋白(SPC)为主要蛋白源,配制了6种等氮等能饲料。其中,饲料SPC作为对照组,未添加氨基酸;饲料SPCF在饲料SPC基础上添加了2.3?A混合物;饲料SPCC、SPCZ、SPCK和SPCT在饲料SPC基础上分别添加了醋酸纤维酯、玉米醇溶蛋白、卡拉胶和棕榈酸甘油酯包被CAA。试验表明:(1)添加CAA和包被CAA均显著提高了牙鲆摄食率(P<0.05),其中以添加CAA效果最好。(2)添加CAA和包被CAA均提高了牙鲆特定生长率(SGR)、饲料效率(FER)和蛋白质效率(PER),其中以SPCT、SPCC组SGR最高;SPCK、SPCT组FER和PER最高。(3)添加CAA和包被CAA均提高了血浆谷草转氨酶(AST)、谷丙转氨酶(ALT)和碱性磷酸酶(AKP)活性,其中以SPCT组AST和ALT活性最高。(4)添加CAA显著提高了血浆尿素氮(UN)和游离氨基酸(FAA)浓度(P<0.05);CAA包被处理后,UN浓度均显著降低(P<0.05);FAA浓度也不同程度地降低,尤其以SPCT组效果最为显著。结果表明以棕榈酸甘油酯包被CAA效果最好。     

饲喂热灭活复合益生菌对牙鲆生长、免疫等指标的影响

将180尾体重(17.50±0.73)g的牙鲆幼鱼随机分为四组,每组添加量分别为饲料重量的0%、0.5%、1.0%和1.5%的复合益生菌,对应T0、T1、T2组和T3组。30 d后,T1、T2组和T3组的鱼体增重率较T0组有明显的增加,且T1组效果更为显著(P<0.05)。随着复合益生菌添加量的增加,T1、T2组和T3组血清中的酸性磷酸酶(ACP),T2组和T3组的碱性磷酸酶(AKP),T2组的总超氧化物歧化酶(TSOD)的活性均有显著性的增加(P<0.05);随着复合益生菌添加量的增加,T1组肝脏中的T-SOD、溶菌酶(LZM)的活性以及T3组的CAT的活性有显著性的增加(P<0.05)。综上,饲料中添加复合益生菌提高了牙鲆的生长性能和部分非特异性免疫,且T1组效果更为明显。     

Experimental Analysis on Allometric Growth in Spualiobarbus curriculus Larvae and Juveniles in Zhaoqing Reach of the Pearl River

Ecological experiment was conducted in this paper to study the allometric growth in Squaliobarbus curriculus larvae and juveniles from Zhaoqing Reach of the Pearl River. The results showed that after first feeding, the organs associated to swimming, feeling and feeding of larvae differentiated rapidly, and exhibited allometric growth. The head length, tail length and head height exhibited positive allometric growth, while trunk length exhibited negative allometric growth before reaching the growth inflexion point 20 d after first feeding, and positive allometric growth after the inflection point. Body height exhibited positive allometric growth both before and after the growth inflexion point at 18 d after first feeding. The inflexion points of snout length, eye diameter and post-eye head length occurred 23, 19 and 16 d after first feeding. For swimming organs, the dorsal fin, pelvic fins and anal fin exhibited positive allometric growth both before and after the inflexion point at 18, 19 and 17 d after first feeding; but the tail fin exhibited positive allometric growth before the inflexion point at 14 d after first feeding, and negative allometric growth after the inflexion point. S. curriculus larvae can possess various abilities soon after first feeding to survive at early stage due to the rapid development of swimming, feeling, feeding and other organs, which has important ecological significance to adapt to the complex external environment.     

The efficacy of amoxicillin sodium against streptococcosis in cultured olive flounder Paralichthys olivaceus and its pharmacokinetics

The efficacy of amoxicillin sodium for controlling field and experimental Streptococcus iniae and S. parauberis infections in olive flounder (Paralichthys olivaceus) was evaluated after a single intramuscular administration. Furthermore, the minimal inhibitory concentrations (MIC) against 21 Streptococcus strains were determined. In addition, the pharmacokinetics and residue depletion in olive flounder were investigated. Single intramuscular doses of amoxicillin sodium at 20, 40, 80, and 160 mg/kg b.w. fish significantly reduced cumulative mortality rates to 18.8–31.3% (P < 0.05) for S. iniae and to 5.0–15.0% (P < 0.01) for S. parauberis, whereas the S. iniae‐ and S. parauberis‐infected positive control groups showed cumulative mortality rates of 68.8% and 60.0%, respectively. In a S. parauberis outbreak, amoxicillin sodium reduced the cumulative mortality rate to 7.5% and 4.8% at 20 and 40 mg/kg b.w. fish, respectively, whereas that of the untreated control group was 35.2%. Peak plasma concentrations (C_max) following a single intramuscular dose of 40 and 80 mg/kg b.w. fish were 62.64 (T_max, 1.59 h) and 87.61 (T_max, 3.02 h) μg/mL, respectively, with large AUC_0?t/MIC and C_max/MIC ratios, and sufficient T > MIC (time for maintaining plasma drug concentration greater than MICs) for S. iniae and S. parauberis. The estimated withdrawal period of amoxicillin sodium from muscle of olive flounder was about 8 days at 40 mg/kg b.w. fish (at 22 ± 1 °C). These results demonstrated a single intramuscular administration of amoxicillin sodium to be effective against streptococcosis in olive flounder.     

DIGFA检测牙鲆腹水病病原的初步研究

旨在建立一种快速检测迟钝爱德华氏菌的斑点免疫金渗滤诊断方法.试验选用硝酸纤维素膜作固相栽体,以胶体金标记羊抗兔IgG,确定迟钝爱德华氏茵免疫血清和金标抗体最佳工作浓度,以出现明显清晰斑点者判定为阳性.结果表明,用该方法检测时,迟钝爱德华氏茵呈阳性,温和气单胞菌、嗜水气单胞菌、河流弧菌、溶藻弧菌、鳗弧菌、腐败希瓦氏菌、产碱普罗威斯登菌、阪崎肠杆菌和大肠杆菌均呈阴性.试验表明,DIGFA方法简便、特异、快速、结果直观,便于在基层推广使用.     

Isolation and characterization of Streptococcus sp. from diseased flounder (Paralichthys olivaceus) in Jeju Island

Streptococcus sp. is gram-positive coccus that causes streptococcal infections in fish due to intensification of aquaculture and caused significant economic losses in fish farm industry. A streptococcal infection occurred from cultured diseased olive flounder (Paralichthys olivaceus) in May, 2005 at a fish farm in Jeju Island, Korea. The diseased flounder exhibited bilateral exophthalmic eyes and rotten gills; water temperature was 16~18℃ when samples were collected. Of the 22 fish samples collected, 3 samples were identified as Lactococcus garvieae and 18 samples were identified as Streptococcus parauberis by culture-based, biochemical test. Serological methods such as slide agglutination, hemolysis and antimicrobial susceptibility test were also used as well as multiplex PCR-based method to simultaneously detect and confirm the pathogens involved in the infection. S. parauberis and L. garvieae have a target region of 700 and 1100 bp., respectively. One fish sample was not identified because of the difference in the different biochemical and serological tests and was negative in PCR assay. In the present study, it showed that S. parauberis was the dominant species that caused streptococcosis in the cultured diseased flounder.     

牛、羊新发病毒性传染病--施马伦贝格病毒

2011年11月在德国西部城镇施马伦贝格检测出一种新型病毒,以其首次阳性病毒标本检出的地名命名为“施马伦贝格病毒”。该病毒能够感染牛、山羊、绵羊等家畜并引起发热、腹泻、乏力等症状,导致动物早产或难产。继德国之后,荷兰、比利时、法国、卢森堡、意大利、西班牙等欧盟8个国家的牛羊等家畜中证实出现疫情。由于现阶段缺乏有效疫苗,被感染牛、羊数量仍在继续上升,引起世界范围内对此病毒的关注,本文就施马伦贝格病毒的危害及在欧洲的传播情况作如下简述,以期为进出口检疫部门和动物引种工作者提供参考。     

被动血凝(PHA)快速检测日本乙型脑炎抗体方法的建立

本文报道了快速检测日本乙型脑炎（乙脑）抗体的被动血凝方法。用PEG提纯乙脑BHK抗原致敏醛化绵羊红细胞可用于人、猪血清中乙脑抗体的检测．该方法具有较高的敏感性和特异性，实验结果表明：该方法与血凝抑制试验具有同等的敏感性，两者符合率为85．12％，与ELISA符合率为91．70％。     

广东省防治犬病毒性疾病研究概况

广东省各地政府部门在严格管理的前提下,积极引导和扶持养犬业的健康发展,如佛山市南海区大沥镇政府把养犬业引入“三高农业”予以积极支持,并在城区开辟近1.8万m2的宠物专业市场,吸引了海内外约130家商户入场经营。南海大沥是公认的沙皮犬正宗原产地,在海内外具有较高的知名度     

鸭坦布苏病毒病研究进展

2010年春,鸭坦布苏病毒病在我国东南沿海暴发,该病由鸭坦布苏病毒引起并以鸭产蛋下降为特征,对养鸭业造成了重大经济损失,对鸭坦布苏病毒病的研究也引起了动物防疫部门及研究者的日益关注。论文从病原学、反向遗传学、病理学、诊断方法、疾病传播及公共卫生安全和疫苗研究等方面对鸭坦布苏病毒病的研究进展进行了概述,有助于对鸭坦布苏病毒的进一步研究及对鸭坦布苏病毒病的预防和控制。