液相色谱—串联质谱法研究恩诺沙星在中华草龟体内的药物代谢动力学

为研究不同给药方式下，恩诺沙星在中华草龟体内的药物代谢动力学规律，实验选取20只健康中华草龟，每组10只，随机分为2组，分别为肌注组和胃插管强制口服组，给药量均为10 mg/kg，应用液相色谱—串联质谱法测定数据，Kinetic 4.4软件的非房室模型分析药时数据。胃插管强制口服给药主要药动学参数为C_max7.49 μg/mL、T_max 12 h、T_1/2λz为99.85 h、AUC_0-∞为531.67 μg/(mL·h)；肌注给药主要药动学参数为C_max 5.85 μg/mL、T_max 4 h、T_1/2λz为30.42 h、AUC_0-∞为193.6 μg/(mL·h)。2种不同给药条件下，肌注恩诺沙星比胃插管强制口服更快达到最高血药浓度，表明肌注恩诺沙星在中华草龟体内吸收更快；胃插管强制口服给药的C_max和AUC均高于肌注给药，表明胃插管强制口服恩诺沙星在中华草龟体内吸收更完全，分布更广泛，效果更好。恩诺沙星在中华草龟体内消除缓慢，滞留时间(MRT)长，胃插管强制口服给药MRT显著长于肌注给药，其血药浓度保留时间长，效果更持久。研究表明，需较快达到疗效时，建议肌注恩诺沙星；需持续给药且龟体代谢状态正常时，建议胃插管强制口服恩诺沙星；恩诺沙星在胃插管强制口服给药条件下，在中华草龟体内血药浓度高、保留时间长、生物利用度高，更适宜作为中华草龟个体疾病治疗的给药方式。     

达氟沙星在健康和鳗弧菌感染牙鲆体内的药物代谢动力学比较

牙鲆随机分为3组，单剂量静注（健康）和口灌（健康对照和鳗弧菌感染）达氟沙星，进行健康和鳗弧菌感染牙鲆比较药动学和生物利用度的研究。药物浓度用高效液相色谱法测定，数据采用MCP-KP自动化药动学分析程序进行分析。结果表明，健康牙鲆静脉注射达氟沙星(5 mg·kg^-1)后，血药经时过程符合无吸收一室开放模型。口灌给药(10 mg·kg^-1)健康及感染牙鲆的血药浓度与时间关系均符合一级吸收一室开放模型；肝脏和肾脏中药物浓度与时间关系均符合一级吸收二室开放模型。与健康牙鲆药动学参数相比较，达氟沙星在鳗弧菌感染牙鲆中的药时曲线下面积由256.07 mg·h^{-1·L-1降为209.18 mg·h-1·L-1，最大血药浓度由5.699 μg·mL-1降低为2.932 μg·mL-1，消除半衰期由27.758 h延长为46.195 h，生物利用度由71.21%降低为58.17%。}     

中东太平洋长鳍真鲨年龄与生长

长鳍真鲨(Carcharhinus longimanus)为大洋性中上层鲨类, 由于其全球资源被过度捕捞, 已被列入 IUCN 濒危物种名录。开展长鳍真鲨年龄鉴定与生长规律的研究, 可为其资源恢复及物种保护提供理论依据。本研究以中东太平洋金枪鱼延绳钓兼捕渔获物中的 87 尾长鳍真鲨为样本(雄性 43 尾, 雌性 44 尾), 结合脊椎骨年龄鉴定结果和生物学数据分析该海域长鳍真鲨年龄及生长规律。赤池信息量准则(AICC)分析表明, 长鳍真鲨脊椎骨半径(r)与全长(L)的关系符合线性回归模型。von Bertalanffy (VB)生长模型为总体观测数据最适模型, 表达式为 L_t=398[1-e^{-0.04(t+6.81)}] , 结合反向逆推个体早期全长数据, 雌性逆推全长的最适模型为 VB 模型 L_{t female} =330.8[1-e^{–0.05( t+5.84)} ] , 雄性为 Gompertz 模型L_{t male} = 363e^{–1.49e( -0.08t )} 雌、雄个体 50%性成熟年龄 t₅₀ 分别为(8.8±1.2)龄和(8.6±1.2)龄, 50%性成熟全长 L₅₀ 分别为(191±9.1) cm 和(173±12.9) cm。     

恩诺沙星及其代谢产物环丙沙星在拟穴青蟹体内的药代动力学

采用高效液相色谱法,研究盐度33条件下恩诺沙星口灌和肌肉注射给药(剂量10 mg/kg)后,恩诺沙星及其代谢物环丙沙星在拟穴青蟹体内的药代动力学和组织分布。血淋巴和组织中药代动力学参数采用基于统计矩原理的非房室模型进行计算。恩诺沙星口灌和肌肉注射拟穴青蟹给药后,血药达峰快,分别为0.5 h和1 min,达峰浓度分别为12.90和31.86 μg/mL,曲线下面积(AUC)分别为216.1和816.8 μg/(mL·h)。恩诺沙星在拟穴青蟹组织中分布较广,口灌给药下肌肉和肝胰腺AUC分别为445.9和817.6 μg/(g·h),肌肉注射给药下的AUC分别为554.7和2 573.7 μg/(g·h)。与其它水产动物相比,恩诺沙星在拟穴青蟹体内消除速度为中等水平,口灌和肌肉注射恩诺沙星后血药消除半衰期(t_1/2z)分别为26.45和57.02 h,总体清除率(CL_z)分别为0.054和0.012 L/(h·kg)。恩诺沙星在拟穴青蟹体内代谢生成环丙沙星的量较少,口灌给药下血淋巴、肌肉和肝胰腺的AUC_CIP/AUC_ENR分别为6.66%、3.66%和4.78%,肌肉注射给药下,其相应值分别为4.16%、7.24%和1.48%,在拟穴青蟹体内起药效作用仍是以恩诺沙星为主。以C_max/MIC、AUC_0-24/MIC评价恩诺沙星在青蟹体内的药效作用,建议给拟穴青蟹以10 mg/kg剂量每隔24小时投喂一次恩诺沙星,对弧菌引起的细菌性疾病具有较好的防治效果。     

中华鳖原生态养殖技术研究

为研究中华鳖原生态养殖技术,在湖南岳阳临湘黄盖湖中华鳖养殖基地进行了生产试验。试验养殖水面36.93 hm²(暂养池2 668 m²,大塘3.33 hm²,大湖33.33 hm²),同时混养部分花白鲢、黄颡鱼、团头鲂和抱卵青虾。从外塘集中培育稚鳖到大湖养殖商品鳖,均采用投喂天然饵料和鲜活饵料,生态调节防控鳖病的原生态的养殖方式,两年养成。大湖养殖成活率高达95.85 %,回捕率81.6 %,平均规格1.15 kg·只-1,平均亩产量28.75 kg(15亩=1 hm²,下同)。通过对外塘和大湖的循环利用,年利润达3 212元·亩-1。采用原生态养殖模式,养成的中华鳖无论外观、抗病力、口感都优于采用普通模式养殖的,生态效益及经济效益均较好。     

氨、亚硝酸盐和硝酸盐对凡纳滨对虾幼虾的毒性作用

研究了 NH₃-N、NO₂ ^- -N与 NO₃ ^- -N对凡纳滨对虾幼虾的毒性作用。获得了 NH₃-N_t(NH₃-N_m) 与 NO₂ ^- -N对体长2．4cm幼虾的 24h、48h、72h、96h之 LC₅₀值，两者对幼虾的安全质量分数分别为1．30 (0．101)mg/L和3．80mg/L。当 NH₃-N_t(NH₃-N_m)质量分数在1．3(0．101)~4．3(0．333)mg/L时，存活率为71．4% ~92．9%，体长增长率为36．3% ~57．1%，体重增长率为188．5% ~322．3%。当 NO₂ ^- -N质量分数在3．00~21．00mg/L时，成活率为75．0% ~91．7%，体长增长率为21．2% ~59．2%，体重增长率为72．0% ~311．9%。NO₃ ^- -N对体长7．37cm幼虾的亚急性毒性效应：NO₃ ^- -N的质量分数在 30~195mg/L时，成活率为 35% ~100%，体长增长率为8．5% ~20．5%，体重增长率为29．6% ~56．8% 。三态氮在一定质量分数范围内均对幼虾的存活率和生长率产生影响。     

低盐度养殖的凡纳滨对虾体长和体重的增长规律

通过池塘陆基围隔实验，研究了凡纳滨对虾在最适水温、溶氧、pH及低盐度(2～6)养殖环境的生长特性及规律。实验结果，低盐度养殖健康对虾体长和体重平均生长率分别为1.398 mm·d^-1和0.169 g·d^-1，对虾前期体长呈线性生长，中后期体重呈加速增长。非线性拟合结果，对虾体长生长为二次曲线，符合Quadratic模型，体重增长为S型曲线，符合Boltzmann模型，生长观测值与模型拟合相关系数R²均达到0.99；凡纳滨对虾低盐度养殖典型体长和体重生长模型为L=7.843+2.297t-0.0105t²和W=16.541+(-0.621-16.541)/(1+e^{(t-54.809)/15.456})。低盐度养殖，对虾体长与体重呈立方关系，符合幂指数模型W=aL^b，a值范围4.9～9.0×10^-6，b值范围2.9495～3.0716，相关系数R²在0.99以上，典型幂指数模型为W=4.9×10^-6L^3.0716。     

西藏哲古措异尾高原鳅年龄、生长及繁殖特性

本研究以耳石为年龄鉴定材料, 结合生物学测量数据, 利用函数拟合求得生长方程, 并解剖观察性腺发育情况, 对采自西藏哲古措的 1616 尾异尾高原鳅(Triplophysa stewarti)开展了年龄、生长及繁殖特性研究。结果发现, 所采集的异尾高原鳅年龄分布为 1~6 龄, 高龄个体较少。体长为 3.47~14.30 cm, 体重为 0.40~28.70 g, 生长特性符合 von Bertalanffy 生长方程: L_t=13.891[1?e^{?0.168(t+2.895)}](R² =0.940); W_t=28.179[1?e^{?0.168(t+2.895)}] ^3.0115(R² =0.991)。拐点年龄为 3.65, 对应的体长和体重分别为 9.26 cm、8.31 g。异尾高原鳅雌雄性比为 1∶3.01, χ² 检验结果显示雌雄差异极显著(P＜0.01)。Fulton 肥满度雄体平均为 1.07, 雌体平均为 1.03; Clark 肥满度雄体平均为 0.88, 雌体平均为 0.76。 异尾高原鳅 1 冬龄达到性成熟。雄性群体成熟系数为 1.57%, 雌性群体为 2.37%。绝对繁殖力为 1040~10176 粒/尾, 平均为 4397 粒/尾。研究结果, 哲古措异尾高原鳅年龄结构简单且低龄化, 生长缓慢, 肥满度低, 雌性个体性腺成熟系数低, 可能是受哲古措特殊的地理位置和生态环境等因素影响。本研究可为高原鳅属鱼类积累基础生物学资料, 并为藏南内流湖泊生态环境及渔业资源保护提供理论依据。     

基于ELEFANI和LBB的竺山湖贝氏䱗资源状况评估

为获得竺山湖水域贝氏?(Hemiculter bleekeri)的种群参数, 评价其资源利用状况, 根据 2019 年 10 月至 2020 年 9 月在竺山湖水域收集的贝氏基础生物学数据 ? , 利用基于长度频率数据的 ELEFAN I (electronic length frequency analysis ) Ⅰ 和贝叶斯评估方法(length-based Bayesian biomass, LBB)估算其种群参数。结果显示, 贝氏体长 ? 范围为 44.17~181.87 mm, 体重范围为 0.88~70.30 g; 体长(L, mm)与体重(W, g)关系式为 W=9.0×10^?5L^3.0707 (R2 = 0.8775, n=805); 体长和体重的生长方程分别为 L_t=194.25×[1?e^{?0.36(t+0.46)}], W_t=95.74×[1?e^{?0.36 (t+0.46)}] ^3.0707。运用 ELEFAN I 方法估算的相对自然死亡系数 M/K=2.28, 相对捕捞死亡系数 F/K=4.50, 相对总死亡系数 Z/K=6.78, 开发率 E=0.66。LBB 估算的相对死亡系数 M/K、F/K、Z/K 和开发率 E 分别为 1.88、5.78、7.64 和 0.76。两种方法估算的种群参数基本一致。本研究揭示了竺山湖贝氏的种群生长特性及资源利用状况 ? , 可为太湖的渔业资源科学管理提供依据。     

环丙沙星在鲤体内吸收、代谢和生物利用度

为评价环丙沙星在水生动物疾病防治上的应用,按10mg·kg~(-1)的剂量分别给鲤静注乳酸环丙沙星水溶液、口服乳酸环丙沙星水溶液、口服乳酸环丙沙星饲料糊。用高效液相色谱测定血浆中药物浓度,用MCPKP药代动力学程序处理药时数据,口服乳酸环丙沙星水溶液和口服乳酸环丙沙星饲料糊的生物利用度分别为10.25％和6.22％。静注给药的药时数据符合无吸收三室开放模型,主要药物代谢动力学的参数如下:t_(1/2α)=0.16h、t_(1/2)π=0.86h、t_(1/2β)=16.47h、V_1=0.10 L·kg~(-1)、Vb=3.03 L·kg~(-1)、Cl_B=0.12 L·kg~(-1)·h~(-1),环丙沙星在鲤体内分布广泛,排泄较慢;口服乳酸环丙沙星水溶液、口服乳酸环丙沙星饲料糊的药时数据均符合具有一个滞后时间的一级吸收二室开放模型;口服乳酸环丙沙星水溶液的主要药物代谢动力学的参数为:t_(1/2α)=0.31h、t_(1/2β)=6.47h、C_(max)=2.14μg·mL~(-1)、T_(max)=0.44h;口服乳酸环丙沙星饲料糊的主要药物代谢动力学的参数为:t_(1/2α)=0.53h、t_(1/2β)=14.47h、C_(max)=0.70μg·mL~(-1)、T_(max)=1.10h,说明鲤口服乳酸环丙沙星水溶液后吸收该药的速度比口服乳酸环丙沙星饲料糊快。从该药的生物利用度结果看,由于环丙沙星在鲤体内的吸收利用程度较低,所以应用该药治疗鲤     

A single-dose pharmacokinetic study of oxolinic acid and vetoquinol, an oxolinic acid ester, in Atlantic halibut, Hippoglossus hippoglossus L., held in sea water at 9 °C

The pharmacokinetic properties of the antibacterial agent oxolinic acid were studied after intravenous, intraperitoneal and oral administration to 1.5–3.0 kg Atlantic halibut, Hippoglossus hippoglossus L., held in sea water at 9 °C. Following intravenous injection, the plasma drug concentration-time profile showed two distinct phases. The terminal elimination half-life was estimated to be 52 h, whereas total body clearance (Cl_T) was determined to be 0.044 L kg^–1 h^–1. The volume of distribution at steady state, V_d(ss), was calculated to be 3.0 L kg^–1, indicating good tissue penetration of oxolinic acid in Atlantic halibut. The peak plasma concentration (C_max) and the time to peak plasma concentration (T_max) were estimated to be 1.2 and 2.7 μg mL^–1, and 21.5 and 80 h, respectively, following oral administration of medicated feed or intraperitoneal injection. The corresponding bioavailabilities were calculated to be 15% and 92%, respectively. Oral administration of vetoquinol, the carbitol ester of oxolinic acid, increased the bioavailability of oxolinic acid to 64% and the total bioavailability (oxolinic acid + vetoquinol) to 82%, whereas C_max and T_max values of 6.7 μg mL^–1 and 14.5 h, respectively, for oxolinic acid, and 1.0 μg mL^–1 and 6.3 h, respectively, for vetoquinol were obtained. Based on a minimum inhibitory concentration (MIC) of 0.0625 μg mL^–1 for susceptible strains, a single intraperitoneal injection of 25 mg kg^–1 of oxolinic acid maintains plasma levels in excess of 0.25 μg mL^–1, corresponding to four times the MIC value, for ≈12 days. The corresponding values for a single oral dose of 25 mg kg^–1 of oxolinic acid and vetoquinol were 5 and 10 days, respectively. For resistant strains with a MIC of 1 μg mL^–1, a single oral dose of vetoquinol (25 mg kg^–1) maintained plasma levels in excess of 4 μg mL^–1 for 34 h.     

A single‐dose pharmacokinetic study of emamectin benzoate in cod,Gadus morhua L., held in sea water at 9 °C

The pharmacokinetic profile of the antiparasitic agent emamectin benzoate was studied in plasma after intravenous (i.v.) injection and in plasma, muscle and skin following oral (p.o.) administration to cod, Gadus morhua, held in sea water at 9 °C and weighing 100–200 g. Following i.v. injection, the plasma drug concentration‐time profile showed two distinct phases. The plasma distribution half‐life (t_1/2α) was estimated as 2.5 h, the elimination half‐life (t_1/2β) as 216 h, the total body clearance (Cl_T) as 0.0059 L kg^?1 h^?1 and mean residence time (MRT) as 385 h. The volume of distribution at steady state, V_d(ss), was calculated to be 1.839 L kg^?1. Following p.o. administration the peak plasma concentration (C_max) was 15 ng mL^?1, the time to peak plasma concentration (T_max) was 89 h and t_1/2β was 180 h. The highest concentration in muscle (21 ng g^?1) was measured after 7 days and t_1/2β was calculated to be 247 h. For skin, a peak concentration of 28 ng g^?1 at 3 days was observed and a t_1/2β of 235 h was determined. The bioavailability following p.o. administration was calculated to be 38%.     

Larval performance of matrinxã, Brycon amazonicus (Spix & Agassiz 1829), after maternal triiodothyronine injection or egg immersion

This study compared the larval performance of matrinxã, Brycon amazonicus, after maternal triiodothyronine (T₃) injection or egg immersion of T₃. In the first experiment, three groups of females (n=4) induced to spawning received pituitary extract (CPE) and a corn oil injection (control), or CPE plus 10 mg or 20 mg kg^?1 bw T₃ dissolved in corn oil (experimental). Larvae were sampled for body weight and length measurement at hatching (0 h) and 12, 24, 36, 48 and 60 h thereafter. Hatching time, hatching success and abnormal development were monitored. In the second experiment, fertilized eggs from four females were immersed in T₃ solutions (0, 0.01, 0.05 and 0.10 mg L^?1) and larvae were sampled at hatching (0 h) and 6, 18, 30, 42, 54, 126 and 198 h thereafter. Hatching time was not affected by either means of hormone treatment. Abnormalities decreased as the T₃ concentration increased in larvae from T₃‐treated broodfish but the number of dead larvae increased proportionally. Larvae from T₃‐injected females had higher weight from 24 h after hatching and greater length from hatching, while the weight of larvae produced from T₃‐immersed eggs changed at 198 h and length from 126 h of rearing. Both routes of T₃ administration affected the early growth of matrinxã but the effect was observed earlier when broodstock females were injected.     

Pharmacokinetic model of florfenicol in turbot (Scophthalmus maximus): establishment of optimal dosage and administration in medicated feed

The pharmacokinetics of florfenicol (FF) in turbot (Scophthalmus maximus) was studied after single intravenous (10 mg kg⁻¹) and oral (100 mg kg⁻¹) administration. The plasma concentration–time data of florfenicol were described by an open one‐compartment model. The elimination half‐life (t_1/2) was estimated to be 21.0 h, and the total body clearance, Cl, was determined as 0.028 L kg h⁻¹. The apparent volume distribution (V_d) was calculated to be 0.86 L kg⁻¹ and the mean residence time (MRT_iv) was 30.2 h. Following oral administration, the maximum plasma concentration (C_max) of 55.4 μg mL⁻¹ was reached at 12 h (T_max). The absorption constant (k_a) was 0.158 h⁻¹. The bioavailability was estimated to be 57.1%. The low bioavailability observed at higher doses was explained by the saturation of the mechanisms of absorption. The drug absorption process was limited by its inherent low solubility, which limited the amount of available FF absorbed in the gastrointestinal tract. Based on the pharmacokinetic data, an optimal dosing schedule for FF administration is hereby provided. Based on the minimum inhibitory concentration found for susceptible strains of Aeromonas salmonicida, oral FF administration of first, an initial dose of 30 mg FF kg⁻¹, followed by 6 maintenance doses at 18 mg kg⁻¹/daily could be effective against furunculosis in turbot.     

Pharmacokinetic/pharmacodynamic properties and P‐glycoprotein expression in pacific white shrimp,Litopenaeus vannamei after oral administration at three dosages of oxolinic acid

The experiments explored the pharmacokinetics (PK) properties of oxolinic acid (OXA) after oral administration at three dosages (10, 30 and 80 mg/kg) via medicated feed in the shrimp. The results showed that the C_max values of 4.31, 14.93 and 16.62 mg/L and AUC_0–∞ values of 92.61, 252.30 and 364.27 mg hr^?1 L^?1 were observed at three OXA dosage groups in the haemolymph respectively. In the hepatopancreas, C_max values of 7.90, 27.23 and 60.51 mg/kg and AUC_0–∞ values of 42.01, 133.06 and 219.06 mg hr^?1 L^?1 were observed at 0.5 hr post administration respectively. In the muscle, C_max values of 1.62, 5.80 and 7.36 mg/kg and the AUC_0–∞ values of 25.64, 98.10 and 134.24 mg hr^?1 L^?1 were observed at 2 hr post administration respectively. In the gills, C_max values of 2.87, 8.08 and 12.12 mg/kg and the AUC_0–∞ values of 51.38, 118.65 and 206.48 mg hr^?1 L^?1 were observed at 4 hr post administration respectively. In addition, the in vitro MIC values of OXA at three dosages against 132 strains of Vibrio were examined and showed that the minimum inhibitory concentration (MIC) values for OXA primarily ranged from 0.15–1.25 µg/ml, including eight strains of Vibrio showing MIC values ≥5 µg/ml. The MIC₅₀ and MIC₉₀ values of 132 strains were 0.62 and 1.25 μg/ml respectively. The AUC_0–24/MIC₉₀ ratios of Vibrio were 140.4 in 30 mg/kg group. Furthermore, the P‐glycoprotein (P‐gp) expression was determined in shrimp tissues after administration to three dosage groups (10, 30 and 80 mg/kg). The results showed that P‐gp expression was up‐regulated in the hepatopancreas (5.36‐, 13.68‐ and 31.06‐fold respectively) compared with the control group.     

Pharmacokinetics of florfenicol and behaviour of its metabolite florfenicol amine in orange‐spotted grouper (Epinephelus coioides) after oral administration

Pharmacokinetics and elimination of florfenicol and florfenicol amine in grouper held in sea water at 23.3 ± 0.8 °C were studied using HPLC method after they were given a single peroral dose of florfenicol at 24 mg kg^?1 body weight. Florfenicol was rapidly absorbed from intestine and distributed extensively to all the tissues examined. The maximum concentrations (C_max, μg g^?1 or μg mL^?1) in plasma and tissues were observed at 2–6 h (the time to reach maximum concentration, T_max) except for bile (T_max = 24 h) and were in the order of intestine (52.02 ± 25.07) > bile (49.41 ± 28.16) > gill (45.12 ± 11.10) > plasma (28.28 ± 5.43) > liver (21.97 ± 12.08) > muscle (21.63 ± 6.12) > kidney (20.88 ± 11.28) > skin (19.10 ± 5.88). The drug distribution level was higher in plasma than in extravascular tissues except for bile, based on the ratios of the area under concentration–time curve between tissue and plasma (AUC_{tissue/plasma}). The elimination of florfenicol was rapid in fish, and the corresponding half‐lives (T_1/2β) in the order of magnitude were bile (13.92 h) > muscle or liver (12.31 h) > skin (11.77 h) > plasma (11.57) > gill (11.04 h) > intestine (10.55 h) > kidney (10.05 h). The delayed T_max, lower C_max and longer T_1/2β for florfenicol amine compared with florfenicol were measured in grouper.     

Pharmacokinetic disposition of enrofloxacin in brown trout (Salmo trutta fario) after oral and intravenous administrations

In this study, the pharmacokinetic profile of enrofloxacin (EF) and its major metabolite, ciprofloxacin (CF), were investigated in brown trout (Salmo trutta fario) (n = 150) after intravenous (i.v.) and oral (p.o.) administrations of a single dose of 10 mg kg^− 1 body weight (b.w.) at 10 °C. The plasma concentrations of the drugs were determined by high-performance liquid chromatography (HPLC-UV) from 0.08 to 120 h. Pharmacokinetic parameters were described by the two-compartment open model for intravenous and oral administrations, respectively. After intravenous administration, the elimination half-life (t_1/2β), apparent volume of distribution at steady-state (V_ss) and total body clearance (Cl_tot) of enrofloxacin were 19.14 ± 1.51 h, 3.40 ± 0.18 L kg^− 1 and 0.14 ± 0.01 L kg h^− 1, respectively. After oral administration, the maximum plasma concentration (C_max), time of maximum concentration (t_max) and bioavailability (F%) were 2.30 ± 0.08 µg mL^− 1, 8 h and 78 ± 4%, respectively. Ciprofloxacin was not detected in the present study. The elimination half-life for enrofloxacin following oral administration was longer than values calculated for other animals. After oral administration, the mean plasma concentration was well above the minimum inhibitory concentrations (MICs)—that is, > 0.5 µg mL^− 1 at 36 h—for most gram-negative fish pathogens. It is possible and practical to obtain therapeutic blood concentrations of enrofloxacin in brown trout (S. trutta fario) using oral administration of 10 mg kg^− 1 body weight; therefore, it may be effective in the therapy for brown trout diseases.     

Pharmacokinetics of sulfamonomethoxine in tongue sole (Cynoglossus semilaevis) after intravenous and oral administration

The pharmacokinetic profiles of sulfamonomethoxine (SMM) were investigated in flatfish tongue soles in the present study. After a single injection of SMM (40 mg/kg BW) to caudal vein of tongue sole at 20 °C, plasma drug concentration versus time data were best fitted to a three-compartment model, characterized with 0.2, 5.7, and 80.4 h for the half-life (t _1/2) of fast distribution, slow distribution, and elimination, respectively. The apparent volume of distribution was 0.1 L/kg, and the body clearance was 0.03 L/h/kg. After oral administration of SMM (200 mg/kg BW) to tongue soles at 20 °C, plasma drug concentrations were best fitted to a two-compartment model, of which the mean half-life of absorption (t _1/2ka) and elimination (t _1/2β ) were 1.7 and 95.7 h, respectively. The maximal absorption concentration (C _max) was estimated as 58 mg/L at 2.5 h, and the mean systemic bioavailability (F) was 39.5 % in tongue soles after oral administration.     

Glycemic response after glucose oral administration of wild juvenile red grouper <Emphasis Type="Italic">Epinephelus morio</Emphasis> fed two different diets

Epinephelus morio is a large carnivorous species of the Caribbean Sea under reproduction in captivity and nutritional physiology. A diet with raw cornstarch (RCS) was compared to a basal diet without starch (basal) to measure plasma glucose, liver glycogen, and intermediary metabolism. Glucose level did not change (p > 0.05) whereas liver glycogen was significantly higher in fish fed the RCS diet (137.2 ± 14.5 mg g^?1) than in fish fed the basal diet (87.4 ± 14.5 mg g^?1). Oral glucose administration (170 mg glucose per 100 g body weight) yielded a slight change; two peaks of plasma glucose were recorded with basal (5.6 mM L^?1) 2 h after oral administration and at 12 h (6.4 mM L^?1). After 24 h, with 1.7 mM L^?1, fish returned to initial stage (2.4 mM L^?1). RCS diet produced the highest level (6.3 mM L^?1) 2 h after oral administration; lowest level observed at 24 h after oral administration (1.0 mM L^?1). A significant effect was detected with the presence or absence of dietary carbohydrates (CBH) on hepatic fructose 1,6-bisphosphatase and pyruvate kinase activity. Grouper used two strategies to maintain glucose homeostasis: CBH present in the diet oriented towards gluconeogenesis, whereas no dietary CBH enhanced glycolytic route to liberate glucose and increase liver glycogen.