盐酸沙拉沙星在锦鲤体内的组织残留研究

健康锦鲤以15 mg/kg的单剂量肌肉注射给药,采用反相高效液相色谱法测定取给药后不同时间的肌肉、肾脏和肝胰脏中盐酸沙拉沙星的质量浓度,用MCPKP软件进行数据处理和分析。结果表明,盐酸沙拉沙星在肾脏、肝胰脏和肌肉组织中的代谢动力学特征不一。肌肉的代谢动力学模型为一级吸收二室开放模型,在肝脏和肾脏组织中代谢动力学模型为一级吸收一室开放模型。数据经回归处理得到3种组织的消除半衰期T1/2肌肉为55.44 h;T1/2肝脏为13.0755 h;T1/2肾脏为33 h。通过休药期公式计算各组织的理论休药期为:肌肉:11.0 d;肝脏:6.6 d;肾脏:9.5 d。以残留量高、消除最慢的组织作为残留分析的靶组织,建议锦鲤以肌肉为残留靶组织,在25℃的条件下,肌肉以10μg/kg为最高残留限量,建议休药期为11 d。     

盐酸沙拉沙星在中华绒螯蟹体内药动学及药效学研究

研究了盐酸沙拉沙星(Sarafloxacin hydrochloride)在中华绒螯蟹(Eriocheir sinensis)雄蟹和雌蟹体内药动学,检测了盐酸沙拉沙星对致病性气单胞菌的最小抑菌浓度(MIC),建立了药动/药效(PK/PD)关系。盐酸沙拉沙星以30 mg.kg-1单剂量口灌给药中华绒螯蟹,雌蟹和雄蟹血浆沙拉沙星浓度-时间关系曲线均符合一级吸收的二室开放动力学模型。雌蟹和雄蟹血药达峰时间(Tmax)为4 h,达峰浓度(Cmax)分别为5.619±1.192 mg.L-1和7.775±1.426 mg.L-1。沙拉沙星在雌蟹和雄蟹体内分布广泛,其表观分布容积(Vd)分别为3.801 L.kg-1和2.871 L.kg-1;消除半衰期(t1/2β)分别为51.982 h和55.956 h,总体清除率(CLs)为0.138 L.(kg.h)-1和0.087 L.(kg.h)-1,曲线下面积(AUC)分别为209.1 mg.(L.h)-1和325.5 mg.(L.h)-1。中华绒螯蟹扣蟹致病菌嗜水气单胞菌HX1b1、维氏气单胞菌CMX313和CMX4对盐酸沙拉沙星的最小抑菌浓度分别为0.5μg.mL-1、0.25μg.mL-1和0.25μg.mL-1。以30 mg.kg-1单剂量给药,嗜水气单胞菌HX1B1的Cmax/MIC值分别为15.55(雄蟹)和11.24(雌蟹)、AUC0-24/MIC值分别为197(雄蟹)和145.4(雌蟹),维氏气单胞菌CMX313和CMX4的Cmax/MIC值分别为31.1(雄蟹)和22.48(雌蟹)、AUC0-24/MIC值分别为394(雄蟹)和290.8(雌蟹)。由此可见,盐酸沙拉沙星在雌雄蟹体内的药动学数据有一定差异,但不是很大。以30 mg.kg-1剂量拌料给药,即可以有效防治上述气单胞菌引起的细菌性疾病。     

多次口灌呋喃唑酮在草鱼体内残留研究

报道了多次口灌呋喃唑酮(60 mg/kg,连续3 d,每天1次)在草鱼体内血浆、肌肉、肝脏和肾脏中的消除与残留研究。采用高效液相色谱法(HPLC)检测用药后不同时间各组织中药物浓度,M ILLEMNIUM32工作站处理原始数据,MCPKP药代动力学软件处理药时数据。结果表明:多次口灌呋喃唑酮在草鱼体内的药时数据符合一级速率吸收一室开放模型,其主要药动学参数为:AUC 2.3182μg.h/m l,Cmax 0.850μg/m l,Ka 0.5515 h-1,K 0.0936 h-1,T1/2ka1.2565h,T1/2k7.4308h,Tp 2.8732 h,药物在血浆、肌肉、肝脏、肾脏中消除时间分别为:72 h、15 d、20 d、20 d。     

盐酸土霉素在奥尼罗非鱼体内的药代动力学及残留研究

在水温(25±2)℃条件下,以15 mg/kg鱼体重的剂量给奥尼罗非鱼单次口灌盐酸土霉素,采用高效液相色谱法测定血浆和肌肉组织中的药物浓度,研究盐酸土霉素在奥尼罗非鱼体内的代谢及消除规律。结果显示:血药时间数据符合一级吸收二室开放模型,半衰期(T1/2Ka、T1/2α、T1/2β)分别为4.79、4.10、45.20 h,最大血药浓度为1.50μg/m L,达峰时间为7.30 h,药时曲线下面积(AUC)为42.35μg·h/m L。肌肉作为可食性组织,选取肌肉组织作为残留检测的靶组织,以0.1 mg/kg为最高残留限量,在本试验条件下,建议休药期不低于10 d。     

甲苯咪唑在银鲫体内的药代动力学研究

采用高效液相色谱法检测甲苯咪唑(MBZ)及其代谢物氨基甲苯咪唑(MBZ-NH2)和羟基甲苯咪唑(MBZ-OH)在银鲫(Carassius auratus gibelio)血浆及组织中的浓度,数据经3P97药代动力学程序分析.结果表明:(25±1)℃的水温条件下,银鲫单剂量口灌MBZ20mg·kg-1,血药经时过程符合二室开放式模型.主要药代动力学参数为:吸收速率常数恐Ka 0.235h-1;消除半衰T(1/2)β 52.26h;药时曲线下面积AUC 180.07μg·h·mL-1;表观容积分布Vd/F 2.465L·kg-1;清除率CL(s)0.111 mL·h-1·kg-1;达峰时间T(peak) 6.20 h;质量浓度Cmax 4.14 μg·mL-1.与哺乳类相比,MBZ在银鲫体内吸收较慢,消除半衰期明显延长,药代动力学参数也有较大差异.建议在做到合理用药的同时加强药物检测力度.     

诺氟沙星在金鳟体内的药物代谢动力学研究

实验水温为15±2℃,金鳟（Oncorhynchus mykiss）（平均体质量100±10g）单剂量肌肉注射30.0 mg/kg诺氟沙星后,应用高效液相色谱（HPCL）法于0.15,0.25,0.5,0.75,1,1.5,2,4,6,8,12,24,48,72 h测定了鱼血浆、肝脏和肾脏组织中药物的浓度,研究了诺氟沙星在金鳟组织中的分布及药物动力学规律。结果表明,诺氟沙星在金鳟体内吸收分布迅速,符合药物动力学一级吸收二室开放模型,但消除缓慢。诺氟沙星在金鳟血浆、肝脏和肾脏中的主要动力学参数如下：分布半衰期（T1/2α）分别为0.866、1.985、0.388h;消除半衰期（T1/2β）分别为31.369、36.402、30.975h;药时曲线下面积（AUC）分别为：308.005μg/mL.h、622.721μg/g.h、794.362μg/g.h。     

两种给药方式下土霉素在鲫鱼体内的药物动力学参数比较

在(10±1)℃水温条件下,研究了土霉素(OTC)经肌肉注射和口灌给药后在鲫体内的药物动力学。将试验鲫随机分为两组:一组采用肌肉注射,另一组采用口灌,两组给药剂量都为50 mg/kg。结果表明:吸收半衰期t1/2(kα)、分布半衰期t1/2(kα)和消除半衰期t1/2(kα)在口灌给药时分别为3.83 h、3.98 h和129.04 h,而在肌肉注射给药时分别为1.58 h、1.71 h、和98.61 h,说明肌肉注射时OTC在鲫体内的吸收、分布和消除比口灌时快;口灌和肌肉注射时,达峰时间分别为15.47 h和7.78 h,肌肉注射的最大药物浓度(12.04μg/mL)比口灌时高(7.20μg/mL)。     

盐酸沙拉沙星在凡纳滨对虾体内药动学与生物利用度

采用RP-HPLC法研究了在盐度33、水温（28.0±1.0）℃的自然海水中盐酸沙拉沙星单剂量围心腔注射（剂量10 mg·kg-1）和单次药饵投喂（剂量30 mg·kg-1）给药后在凡纳滨对虾（Litopenaeus vannamei）体内的药动学与生物利用度。围心腔注射给药后,血淋巴中药时曲线较适合用二室模型来拟合,而药饵投喂给药后血淋巴中药时曲线较适合采用一级吸收二室模型来拟合。药饵给药下盐酸沙拉沙星在凡纳滨对虾体内的生物利用度（F）为61.6%。药饵投喂给药下大量药物分布到了肝胰腺,肝胰腺血药峰浓度（Cmax）和AUC0-t分别是血淋巴的24.4倍和18.7倍,分别是肌肉的51.9倍和62.0倍;药物在肝胰腺和肌肉中消除都很快,分别在给药后5 d 和36 h低于0.1 mg·kg-1。由此可见,盐酸沙拉沙星药饵给药下吸收好,达峰值高和生物利用度好,且在肌肉和肝胰腺组织中消除快,是较为理想的防治对虾细菌性疾病的抗菌药物。     

中药诃子的主要成分没食子酸在异育银鲫体内药物代谢动力学研究

在(20±1)℃的水温条件下,以77 mg/kg的单剂量,给异育银鲫(Carassius auratus gibelio)口灌诃子(Fructus chebulae)水剂,以诃子中的主要成分没食子酸为检测目标,用高效液相色谱法(HPLC)检测给药后各个时间点的血药浓度。结果显示:最低检测限为0.01μg/mL,线性范围为0.01～84.00μg/mL。诃子在异育银鲫体内的药动学过程符合一级吸收二室开放房室模型(1/C/C),其药物动力学方程为C=39.237e-0.320t+4.814e-0.006t,主要药动学参数为:吸收速率常数(Ka)为0.56 h-1,吸收半衰期(t1/2ka)为1.238 h,分布半衰期(t1/2α)为2.164 h,消除半衰期为(t1/2β)为119.369 h,达峰时间(Tmax)为4 h,最大血药浓度(Cmax)为11.024μg/mL,血药浓度-时间曲线下面积(AUC(0-∞))=674.89μg.h/mL,延滞时间(TL)为0.286 h,药物平均滞留时间(MRT(0-∞))=113.626 h,总体消除率(CLs)为0.112 L/(kg.h),表观分布容积(Vd)为13.713 L/kg。这些参数表明,异育银鲫口灌诃子后,能比较迅速被吸收,并且在血浆中维持较长的时间,具有较好的应用价值基础。     

恩诺沙星及其代谢物环丙沙星在欧洲鳗鲡体内的代谢动力学

采用高效液相色谱法,研究药饵口灌给药途径下,恩诺沙星及其代谢物环丙沙星在欧洲鳗鲡(Anguilla anguilla)体内的药代动力学。欧洲鳗鲡口灌给药恩诺沙星10 mg/kg后,其血浆、肌肉和肝脏中药物时量曲线关系符合一级吸收的二室开放动力学模型。恩诺沙星在欧洲鳗鲡不同组织中分布较广,血浆、肌肉和肝脏的Vd分别为6.362 L/kg、8.081 L/kg和15.870 L/kg;恩诺沙星在鳗鲡体内消除较慢,在血浆、肌肉和肝脏中的消除半衰期(tβ1/2)分别为161.10 h、333.21 h和611.26 h,总体清除率(CLs)分别为27.4 mL/(kg.h)、16.8 g/(kg.h)和18.0 g/(kg.h)。代谢物环丙沙星在鳗鲡血浆、肌肉和肝脏中药物水平的变化趋势与恩诺沙星基本相似,呈现出多峰现象,但3种组织中环丙沙星出现第一个药峰时间分别为给药后第24小时、24小时和12小时,3种组织中环丙沙星峰值水平肝脏中最高、肌肉中次之、血浆中最低,环丙沙星在肌肉和肝脏中的消除速率比较缓慢。鉴于恩诺沙星和其代谢物环丙沙星在欧洲鳗鲡体内消除较慢,建议养成阶段使用其他药物。     

Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean

The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.     

Rare serotype occurrence and PFGE genotypic diversity of Streptococcus agalactiae isolated from tilapia in China

Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China.     

Evaluation of a Fast Method Based on the Presence of Two Restriction Sites in the Mitochondrial ND5 (mt ND5) Gene for the Identification of Scomber Species

The purpose of this work was to evaluate the suitability of a method based on the presence of two restriction sites (for Hae III and Hindf I) in the mitochondrial NADH dehydrogenase subunit 5 (mt ND5) gene to identify Scomber species. The evaluation was performed on 144 reference and market samples by sequencing of the entire 505-bp fragment of the mt ND5 gene and of a 464-bp fragment of the Kocher fragment of the cytochrome b gene (mt Cytb). Sequence analysis of any of the two fragments allows the identification of each of the four Scomber species, but S. japonicus and S. colias had the same restriction sites at the ND5 amplicon and would not have been differentiated by this analysis. Similarly, loss of the Hae III site in some S. scombrus individuals would have misidentified them as not being Scomber. All the market products were correctly labeled except one acquired in Spain labeled as originating in the Atlantic and containing S. japonicus.     

Growth performance,digestive enzyme activity and immune response of Japanese sea bass,Lateolabrax japonicus fed with fructooligosaccharide

In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.     

Purification and partial characterization of GtHs (cfLH and cfFSH) from Indian walking catfish (Clarias batrachus) (L.) and development of a homologous ELISA for cfLH

Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL^?1 (1.25 ng well^?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation.     

Controlled infection of Poecilia reticulata Peters (guppy) with Tetrahymena by immersion and intraperitoneal injection

Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg^?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality).     

The optimal dietary protein level of juvenile silver sillago Sillago sihama at three dietary lipid levels

A 5 × 3 factorial growth trial was conducted to evaluate optimal dietary protein and lipid levels (dietary protein level, DP; dietary lipid level, DL) for juvenile Sillago sihama (S. sihama) (2.0 ± 0.02 g, initial weight). Fish were fed 15 diets containing 5 DPs (350, 400, 450, 500 and 550 g/kg) and 3 DLs (60, 90 and 120 g/kg) for 8 weeks. The interaction between proteins and lipids significantly influenced the feed conversion ratio, condition factor, body composition, antioxidant indices and lipase activity (p < .05). DP 450 g/kg showed the highest average final body weight. DPs 500 and 550 g/kg significantly decreased the protein efficiency ratio (p < .05). DL 120 g/kg showed the highest percentage weight gain. The low feed conversion ratio was found in diets P45L12, P55L9 and P55L12. Diet P45L12 showed high superoxide dismutase activities. DP 450 g/kg showed the lowest average malondialdehyde content. Lipase activity was increased by increasing DP (p < .05) with a fall at DP 550 g/kg. Under the present experimental conditions, the optimal DP for S. sihama was 450 g/kg under the DL 120 g/kg.     

Vitamin D3 and the renal handling of phosphate in American eels

Cholecalciferol (Vitamin D₃) increased plasma inorganic phosphate concentration in American eels,Anguilla rostrata, in a dose-dependent fashion. This response was more marked in phosphate loaded fish. In control as well as phosphate loaded eels the hyperphosphatemic response to D₃ was associated with a sharp reduction in renal phosphate clearance relative to¹⁴C-polyethelene glycol (PEG) clearance. Glomerular filtration and urine flow rates were not affected by D₃. As renal phosphate clearance, even in phosphate loaded eels, never significantly exceeded that of PEG, it is suggested that D₃ reduced the relative clearance rate of phosphate by increasing renal phosphate reabsorption rather than by reducing the tubular secretion of phosphate.