达氟沙星对史氏鲟血浆及肝脏蛋白含量的影响

用不同剂量(20，50，100mg／kg)的达氟沙星连续口灌史氏鲟，于首次给药后的第5，10，15，20天采集其血液和肝脏，用考马斯亮兰试剂盒测定血浆蛋白和肝脏蛋白含量。结果表明：达氟沙星对史氏鲟血浆蛋白含量无显著影响，而对肝脏蛋白含量有一定的影响，表现为各剂量组肝脏蛋白含量均低于对照组，但仅第20天高剂量组与对照组有统计学上的差异性。自给药后第5天各剂量组史氏鲟肝脏蛋白含量下降较明显，随给药时间延长，20mg／kg组史氏鲟肝脏蛋白含量逐渐升高，50mg／kg剂量组和100mg／kg剂量组史氏鲟肝脏蛋白含量先升后降，其中100mg／kg剂量组下降较为明显。     

N-乙酰半胱氨酸对肉鸭肝脏能量代谢状况及组织抗氧化指标的影响

为考查N-乙酰半胱氨酸(NAC)是否可以改善肉鸭肝脏的能量代谢状况及组织抗氧化能力,试验选用90只1 d樱桃谷肉鸭,随机分成3个处理组:对照组(基础日粮)、500 mg/kg NAC组(基础日粮+500 mg/kg NAC)、1 000 mg/kg NAC组(基础日粮+1 000 mg/kg NAC),每组3个重复,每个重复10只鸭。试验期为3周(1~21日龄)。结果表明:与对照组相比,日粮添加500 mg/kg NAC显著提高了血浆、肝脏的过氧化氢酶(CAT)、超氧化物歧化酶(SOD)的活力及肝脏谷胱甘肽过氧化物酶(GSH-Px)的酶活力、三磷酸腺苷(ATP)、二磷酸腺苷(ADP)的含量和能荷(EC)值(P0.05),显著降低了血浆丙二醛(MDA)和肝脏过氧化氢(H2O2)的含量及肝脏AMP/ATP值和肝脏低氧诱导因子1(HIF-1)、黄嘌呤氧化还原酶(XOR)的m RNA水平(P0.05);1 000 mg/kg NAC组显著提高了血浆和肝脏CAT、SOD的活力及肝脏GSH-Px的酶活力、ATP的含量、EC值和AMPK-α1的m RNA水平(P0.05),显著降低了血浆和肝脏H2O2的含量及肝脏MDA的含量、HIF-1、XOR的m RNA水平。表明NAC可以提高肉鸭的组织抗氧化能力、改善肝脏的能量代谢,这可能与NAC对AMPK-α1、HIF-1及XOR的基因表达调控有关。     

茵陈水提物对镉中毒所致小鼠肝氧化应激的保护作用

目的:观察茵陈水提物对镉中毒所致小鼠肝脏氧化应激的保护作用。方法:将实验小鼠随机分为对照组,镉中毒组,茵陈水提物高、低剂量组。镉中毒组采用饮水染毒(氯化镉浓度为50 mg/L),茵陈水提物高、低剂量组(40 m L/kg、20 m L/kg)均以灌胃给药,1次/d,30 d后采样检测小鼠血清中谷丙转氨酶(ALT)和谷草转氨酶(AST)的活力以及肝组织中超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、谷胱甘肽(GSH)活力和丙二醛(MDA)含量。结果:茵陈水提物可明显降低镉中毒小鼠血清中ALT和AST活力,增强镉中毒小鼠肝组织中SOD、GSH-Px、GSH的活力,并降低MDA含量。结论:茵陈水提物可抑制镉中毒所致小鼠肝脏的氧化应激,对镉中毒所致小鼠肝损伤有保护作用。     

白藜芦醇对玉米赤霉烯酮致小鼠肝脏氧化损伤及炎症的保护作用

为探究白藜芦醇（RSV）对玉米赤霉烯酮（ZEA）中毒小鼠肝脏损伤是否具有保护作用,试验将40只清洁级雄性BALB/c小鼠随机分为5组：对照组（生理盐水）、ZEA组（40 mg/kg）、不同浓度的RSV （50、100或200 mg/kg）与ZEA （40 mg/kg）共处理组,每组8只,各组均灌胃给药,试验期12 d。试验结束后采集小鼠肝脏样品,计算肝脏系数,采用苏木素-伊红（HE）染色和免疫组织化学染色法观察各组肝脏病理变化;检测肝脏NF-κB蛋白表达;比色法检测肝脏组织中丙二醛（MDA）含量、超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性及血清中谷丙转氨酶（ALT）、谷草转氨酶（AST）和乳酸脱氢酶（LDH）活性,ELISA法检测血清中白细胞介素-6（IL-6）、肿瘤坏死因子-α（TNF-α）和IL-1β含量。结果显示,与对照组相比,ZEA组小鼠肝组织发生明显病理学变化;与ZEA组相比,不同浓度RSV与ZEA共处理组小鼠肝脏组织病理学变化都有所减轻。免疫组织化学结果显示,与对照组相比,ZEA组肝脏NF-κB蛋白表达增多;与ZEA组相比,不同浓度的RSV与ZEA共处理组肝脏NF-κB蛋白表达均有下降。与对照组相比,ZEA组肝脏系数和肝脏组织MDA含量极显著升高（P<0.01）,肝脏组织SOD和CAT活性显著或极显著降低（P<0.05;P<0.01）,血清中AST、ALT和LDH活性,IL-6、TNF-α和IL-1β含量均极显著升高（P<0.01）。与ZEA组相比,不同浓度RSV与ZEA共处理组肝脏组织CAT活性显著或极显著升高（P<0.05;P<0.01）,血清中AST、ALT和LDH活性及IL-6和IL-1β含量显著或极显著降低（P<0.05;P<0.01）;50 mg/kg RSV与ZEA共处理组肝脏组织SOD活性和血清中TNF-α含量分别显著升高（P<0.05）和极显著降低（P<0.01）;100和200 mg/kg RSV与ZEA共处理组肝脏系数和肝脏组织MDA含量显著或极显著降低（P<0.05;P<0.01）。结果表明,ZEA对小鼠肝脏有严重的氧化及炎症损伤作用,RSV对ZEA中毒的肝损伤具有一定保护作用,尤其以100 mg/kg RSV保护效果最佳。     

中药复方制剂"延命散"的量效关系研究

选择给药后血清中超氧化物歧化酶(SOD)活力升高率为药效学指标,对动物保健中药复方制剂“延命散”进行了量效关系研究。结果表明:在给药剂量1.038×103mg/kg体重与2×104mg/kg体重之间,“延命散”对血清中SOD活力的升高率呈现一定的量效关系。而当剂量大于2×104mg/kg体重时,随着剂量的增大,SOD活力的升高率逐渐降低,甚至出现负增长,给药剂量达到1×105mg/kg体重时,SOD活力下降到340.40±63.18Nu/mL,显著低于空白对照组(P<0.05),SOD活力降低了18.55%,表现出对酶活力的抑制作用。由此可见,在中兽药的研究和开发中,确定科学合理的给药剂量,进行量效关系的研究至关重要。     

中药复方制剂"宠康"的量效关系研究

选择给药后血清中超氧化物歧化酶(SOD)活力升高率为药效学指标,对动物保健中药复方制剂"宠康"进行了量效关系研究.结果表明在给药剂量1.038×103 mg/kg体重与2×104 mg/kg体重之间,"宠康"对血清中SOD活力的升高率呈现一定的量效关系.而当剂量大于2×104 mg/kg体重时,随着剂量的增大,SOD活力的升高率逐渐降低,甚至出现负增长,给药剂量达到1×105 mg/kg体重时,SOD活力下降到340.40±63.18 Nu/mL,显著低于空白对照组(P<0.05),SOD活力降低了18.55%,表现出对酶活力的抑制作用.由此可见,在中兽药的研究和开发中,确定科学合理的给药剂量,进行量效关系的研究至关重要.     

日粮铜水平对兔血铜含量及两种酶活性的影响

在含铜10.56mg/kg的基础日粮中添加0、10、20、100、200mg/kg铜，分别饲喂五组90日龄的安哥拉兔，研究日粮铜水平对兔血铜含量及两种酶活性的影响。结果表明，不同铜处理组间，兔体内SOD酶和铜兰蛋白酶的活性以及兔血浆铜含量差异不显著（P＞0.05)；但血浆铜兰蛋白酶的活性明显地随铜添加量的增加而增加，试验期末高铜E组该酶活力平均比对照组提高60％；肝SOD酶活力也有随日粮铜水平增加而增加的趋势；血浆、红细胞中的含铜量及红细胞中SOD酶活性没有明显的变化规律。     

麦麸阿魏酰低聚糖对敌草快致氧化应激大鼠血浆和组织抗氧化能力的影响

本试验以酿酒酵母和枯草芽孢杆菌作为混合菌种发酵小麦麸皮,通过Amberlite XAD-2柱分离纯化制备麦麸阿魏酰低聚糖(feruloyl oligosaccharides,FOs),探讨麦麸FOs对敌草快(diquat)诱导的大鼠氧化应激是否有缓解作用。试验选用体重相近的断奶雄性大鼠48只,随机分为未攻毒组、攻毒组、攻毒+100 mg/kg BW麦麸FOs组、攻毒+200 mg/kg BW麦麸FOs组、攻毒+300 mg/kg BW麦麸FOs组和攻毒+100 mg/kg BW维生素C组,每组8个重复,每个重复1只鼠,各组大鼠均饲喂相同的商业饲料。麦麸FOs和维生素C配制成水溶液,采用灌胃的方式给予,未攻毒组、攻毒组用生理盐水替代,灌胃体积0.2 mL,连续灌胃15 d。灌胃结束当天,未攻毒组大鼠注射0.3 mL生理盐水,其他5组按0.1 mmol/kg BW的剂量腹腔注射0.3 mL敌草快。敌草快攻毒12 h后取样,分析各组大鼠血浆以及肝脏、肾脏和回肠中总抗氧化能力(T-AOC),过氧化氢酶(CAT)、超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)活性以及谷胱甘肽(GSH)和8-羟基脱氧鸟苷(8-OHd G)的含量。结果显示:1)通过混菌发酵小麦麸皮制备麦麸FOs,利用Amberlite XAD-2柱进行分离纯化,获得的麦麸FOs浓度为0.059 mmol/g。2)腹腔注射敌草快显著降低大鼠血浆中SOD活性和GSH含量(P0.05),显著降低大鼠肝脏中T-AOC,CAT、GSH-Px活性及GSH含量(P0.05),显著降低大鼠肾脏中T-AOC及CAT、SOD活性(P0.05),显著降低大鼠回肠中T-AOC,CAT、GSH-Px活性及GSH含量(P0.05),并显著提高大鼠血浆和各组织中8-OHd G含量(P0.05)。3)在敌草快引起的氧化应激状态下,灌胃一定剂量的麦麸FOs可以显著提高大鼠血浆中SOD(400 mg/kg BW)、GSH-Px活性(100和200 mg/kg BW)以及GSH含量(100和200 mg/kg BW)(P0.05),显著提高大鼠肝脏中T-AOC(100、200和400 mg/kg BW),CAT(200和400 mg/kg BW)、SOD(100、200和400 mg/kg BW)和GSH-Px活性(100、200和400 mg/kg BW)以及GSH含量(100、200和400 mg/kg BW)(P0.05),显著提高大鼠肾脏中T-AOC(400 mg/kg BW),CAT(200 mg/kg BW)和GSH-Px活性(200和400 mg/kg BW)以及GSH含量(400 mg/kg BW)(P0.05),显著提高大鼠回肠中T-AOC(200 mg/kg BW),SOD(400 mg/kg BW)和GSH-Px活性(100、200和400 mg/kg BW)以及GSH含量(100、200和400 mg/kg BW)(P0.05),显著降低血浆和各组织中8-OHd G含量(血浆、肾脏、回肠:100、200和400 mg/kg BW;肝脏:100 mg/kg BW)(P0.05);且灌胃200、400 mg/kg BW麦麸FOs后,大鼠血浆和组织中部分抗氧化相关指标可恢复到正常生理状态水平。综上所述,本试验制备的麦麸FOs可以通过有效提高大鼠血浆和组织中抗氧酶活性和GSH含量,降低DNA氧化应激代谢产物8-OHd G的含量,有效缓解由敌草快诱导产生的氧化应激。     

黄芪多糖对己烯雌酚诱导的小鼠睾丸损伤保护作用研究

为探讨黄芪多糖(APS)对己烯雌酚(DES)诱导的成年小鼠睾丸损伤的保护作用,将40只雄性小鼠分为正常对照(A)、3个黄芪多糖组(B、C、D)和己烯雌酚组(E)。B组、C组、D组分别灌服20、60、100mg/kg的APS,A组每只灌胃0.2mL含量为5g/L的羟甲基纤维素钠,E组每只灌胃0.2mL生理盐水。4h后除A组外,其他4组腹腔注射40mg/kg的DES,A组腹腔注射相同剂量橄榄油。连续给药7d。处理结束后计算睾丸重量及其脏器系数,检测睾丸病理学变化,检测睾丸中超氧化物歧化酶(SOD)活力、谷胱甘肽过氧化物酶(GSH-Px)活力和丙二醛(MDA)的含量;检测血清中睾酮(T)、促黄体素(LH)和促性腺激素释放激素(GnRH)的水平。结果表明,与DES模型组相比较,APS各组睾丸脏器系数变化差异显著,睾丸组织学变化有明显改善。抗氧化结果显示,APS各剂量组睾丸组织中SOD、GSH-Px活力均高于DES组,差异显著,其中100mg/kg组最高。APS各剂量组睾丸组织中MDA含量均低于DES组,差异显著,其中60mg/kg组最低。APS各剂量组血清中T、LH、GnRH的含量均显著增加。结果提示,APS对DES诱导的小鼠睾丸损伤有显著缓解作用。     

抗菌肽添加量对杂交鲟生化指标的影响

为研究抗菌肽添加量对杂交鲟血清和组织免疫相关指标和抗损伤能力的影响。挑选体格健壮、大小一致的杂交鲟（俄罗斯鲟Acipenser gueldenstaedtii♀×史氏鲟Acipenser schrencki Brandt♂）200尾，随机分成4组。对照组投喂基础饲料，Ⅰ、Ⅱ、Ⅲ组分别在基础饲料中添加400、800和1 200 mg/kg的抗菌肽，在（16.0±1.0）℃水温条件下养殖30 d。结果表明，摄食添加抗菌肽的杂交鲟，其血清和组织中白蛋白（ALB）和总蛋白（TP）含量随抗菌肽质量浓度的增加先增后减，其中Ⅱ组杂交鲟血清和组织中ALB和TP含量显著高于对照组（P<0.05）。血清中谷草转氨酶（GOT）和乳酸脱氢酶（LDH）活性随抗菌肽质量浓度的增加先降低后增加；Ⅰ组杂交鲟血清和组织中GOT活性显著低于其他组（P<0.05）；而Ⅲ组GOT和LDH活性显著高于其他组（P<0.05）。杂交鲟组织中总胆固醇（TCHO）含量随抗菌肽质量浓度的增加逐渐减少，Ⅲ组TCHO含量在组织中显著低于其他组（P<0.05）。溶菌酶（LZM）活性随抗菌肽质量浓度的增加而逐渐增加，Ⅱ、Ⅲ组杂交鲟心脏、脾脏和小肠中LZM活性显著高于其他组（P<0.05）。因此，在基础饲料中添加抗菌肽可有效提高杂交鲟的部分非特异性免疫能力和抗损伤能力，抗菌肽添加剂量在400~800 mg/kg时效果最佳。     

中华鲟幼鲟维生素C营养需要的研究

本研究旨在确定中华鲟幼鲟对维生素C(VC)的营养需要量。配制含VC分别为0.5、59.8、119.5、239.1、478.1和956.2 mg/kg饲料的6组日粮(分别编号为C0.5、C59.8、C119.5、C239.1、C478.1和C956.2),连续投喂中华鲟幼鲟8周后,以生长速度、组织VC含量和部分相关酶活性来确定中华鲟对VC的需求量。结果表明,C0.5和C59.8组鲟鱼的增重率、饲料效率、蛋白质效率都低于C119.5组,进一步提高饲料VC含量,也没有显著变化(P>0.05);C478.1组的肝脏和肌肉组织VC含量达最高水平;C239.1组血清溶菌酶活性最高;C239.1组SOD活性最低。根据平均增重率和饲料效率做折线法分析表明,维持中华鲟最佳生长的饲料VC含量为108.5 mg/kg;肝脏中VC含量达最大时饲料VC添加量为309.4 mg/kg;肌肉中VC含量达最大时饲料VC添加量为273.3 mg/kg。     

变温条件下不同投喂水平对施氏鲟幼鱼消化酶、代谢酶和抗氧化酶活性的影响

本试验旨在研究变温条件下不同投喂水平对施氏鲟幼鱼消化酶、代谢酶和抗氧化酶活性的影响。试验水温设恒温[(22.0±0.1)℃]和变温[(22±2)℃]2种模式,并根据投喂水平分为6组,分别为恒温100%饱食组(HW-100组)、变温100%饱食组(BW-100组)、变温90%饱食组(BW-90组)、变温80%饱食组(BW-80组)、变温70%饱食组(BW-70组)、变温60%饱食组(BW-60组)。将平均体重为(34.9±0.8)g的施氏鲟幼鱼随机分为6组,每组4个重复,每个重复15尾鱼,养殖周期为42 d。结果表明:变温条件下,在60%~80%范围内,随着投喂水平的降低,胃及瓣肠蛋白酶活性均显著升高(P0.05)。与HW-100组相比,BW-60组与BW-70组的胃和瓣肠蛋白酶活性均显著升高(P0.05)。变温条件下,十二指肠和瓣肠淀粉酶活性及瓣肠脂肪酶活性均随投喂水平的降低呈先升高后下降的趋势。BW-80组十二指肠淀粉酶活性显著高于HW-100组及BW-100组(P0.05),BW-80组和BW-90组瓣肠淀粉酶活性显著高于其他各组(P0.05)。所有变温投喂组瓣肠脂肪酶活性均显著低于HW-100组(P0.05)。除BW-70组外,各变温投喂组血清丙氨酸转氨酶(ALT)活性均显著高于HW-100组(P0.05)。与HW-100组相比,BW-60组、BW-70组血清超氧化物歧化酶(SOD)活性显著降低(P0.05)。在变温条件下,在60%~90%范围内,鱼体血清总抗氧化能力(T-AOC)和黄嘌呤氧化酶(XOD)活性均随着投喂水平的降低整体呈先下降后上升的趋势,且均在投喂水平为80%时降至最低值。与HW-100组相比,BW-60组、BW-70组及BW-100组血清T-AOC显著升高(P0.05),且BW-60组和BW-90组血清XOD活性显著升高(P0.05)。综上所述,在周期性变温条件下,施氏鲟幼鱼可通过提高蛋白酶活性,即提高对饲料蛋白质消化效率的方式来补偿其对饲料蛋白质摄入的不足。与恒温100%饱食相比,变温条件下各投喂水平均可提高施氏鲟幼鱼血清ALT活性。     

Pharmacokinetics of norfloxacin and its N-desethyl- and oxo-metabolites in broiler chickens.

Norfloxacin was given to 2 groups of chickens (8 chickens/group) at a dosage of 8 mg/kg of body weight, IV and orally. For 24 hours, plasma concentration was monitored serially after each administration. Another group of chickens (n = 30) was given 8 mg of norfloxacin/kg orally every 24 hours for 4 days, and plasma and tissue concentrations of norfloxacin and its major metabolites desethylenenorfloxacin and oxonorfloxacin were determined serially after the last administration of the drug. Plasma and tissue concentrations of norfloxacin, desethylenenorfloxacin, and oxonorfloxacin were measured by use of high-performance liquid chromatography. Pharmacokinetic variables were calculated, using a 2-compartment open model. For norfloxacin, the elimination half-life (t1/2 beta) and the mean +/- SEM residence time for plasma were 12.8 +/- 0.59 and 15.05 +/- 0.81 hours, respectively, after oral administration and 8.0 +/- 0.3 and 8.71 +/- 0.23 hours, respectively, after IV administration. After single oral administration, norfloxacin was absorbed rapidly, with Tmax of 0.22 +/- 0.02 hour. Maximal plasma concentration was 2.89 +/- 0.20 microgram/ml. Oral bioavailability of norfloxacin was found to be 57.0 +/- 2.4%. In chickens, norfloxacin was mainly converted to desethylenenorfloxacin and oxonorfloxacin. Norfloxacin parent drug and its 2 major metabolites were widely distributed in tissues. Considerable tissue concentrations of norfloxacin, desethylenenorfloxacin, and oxonorfloxacin were found when norfloxacin was administered orally (8 mg/kg on 4 successive days). The concentration of the parent fluoroquinolone in fat, kidneys, and liver was 0.05 micrograms/g on day 12 after the end of dosing.     

Use of electrosense in the feeding behavior of sturgeons

The electro-receptive lateral line system appeared early in the evolutionary history of fish. Sturgeons, members of the primitive Chondrostei group, are known for their electroreceptors (ampullae of Lorenzini) on the head, which are thought to be sensitive to weak electric fields in aquatic environments and involved in feeding, mating and migration. Here, we report the results of a set of behavioral and electrophysiological experiments designed to determine the function and characteristics of the electrosense in cultured sturgeons. The results showed Siberian sturgeon (Acipenser baerii Brandt, 1869) feeding striking at bio-electric fields produced by living feed-fish enclosed in a gel chamber and at the corrosion field produced by metal rods. With an electric stimulus that mimics the bio-electric fields produced by living prey, the relative discharge rate of electrosensory neurons in the dorsal octavolateralis nucleus (DON) was modulated by and phase-locked to sinusoidal stimulus and some units showed selectivity for dipolar direction in white sturgeon (Acipenser transmontanus Richardson, 1836). This is the first study to provide the empirical evidence correlating with electrosensory behaviors and electrophysiological responses in cultured sturgeons, and suggesting that electrosense does play an innate role in feeding behavior of sturgeon. We believe this will have important implications for protecting sturgeons in the wild.     

Hematology and plasma chemistry reference intervals for cultured shortnose sturgeon (Acipenser brevirostrum)

BACKGROUND: The shortnose sturgeon, Acipenser brevirostrum, is an imperiled species distributed along the Atlantic coast of North America. Interest in replenishing wild stocks with hatchery-reared fish has created a need for accurate hematologic and biochemical reference intervals to evaluate the health of both fish raised in aquaculture systems and fish in the wild. OBJECTIVES: The objective of this study was to generate hematologic and biochemistry reference intervals for healthy shortnose sturgeon. METHODS: Blood samples were collected in heparinized tubes from 77 shortnose sturgeon raised in flow-through aquaculture systems. Whole blood and plasma samples were analyzed for hematologic and biochemical variables using standard techniques. Reference intervals were calculated as the central 95% (percentile) of data. RESULTS: Hematologic reference intervals (n = 46) were as follows: PCV 26-46%, hemoglobin 5.7-8.7 g/dL, MCV 307-520 fL, MCH 65.9-107.1 pg, MCHC 15-30 g/dL, plasma proteins (refractometry) 2.8-6.0 g/dL, RBC count 0.65-1.09 x 10(6)/microL, total WBC count 28,376-90,789/microL, small lymphocytes 9063-56,656/microL, large lymphocytes 2122-10,435/microL, neutrophils 3758-33,592/microL, monocytes 0-7137/microL, eosinophils 0-1544/microL, thrombocyte-like cells 6863-23,046/microL, thrombocytes 32,205-122,179/microL, and neutrophil:lymphocyte ratio 0.068-1.026. Plasma chemistry reference intervals (n = 77) were as follows: total protein 2.7-5.3 g/dL, albumin 0.8-1.7 g/dL, globulins 1.8-3.7 mg/dL, creatinine 0-1.4 mg/dL, total bilirubin 0-0.1 mg/dL, alkaline phosphatase 47-497 U/L, aspartate aminotransferase 90-311 U/L, sodium 124-141 mmol/L, potassium 2.9-3.7 mmol/L, chloride 106-121 mmol/L, calcium 6.6-12.1 mg/dL, magnesium 1.6-2.3 mg/dL, phosphorus 5.1-8.1 mg/dL, glucose 37-74 mg/dL, cholesterol 42-133 mg/dL, and osmolality 232-289 mOsm/kg. CONCLUSION: Reference values reported here will be useful for the early detection, identification, and monitoring of disease and sublethal conditions in cultured shortnose sturgeon.     

Lymphoid organs in sturgeons (Acipenseridae)

Lymphoid (lymphomyeloid) tissues in sturgeons (hybrid sturgeon, Huso huso X Acipenser ruthenus, and white Pacific sturgeon, A. transmontanus) were investigated by dissection, histology and transmission electron microscopy. The main lymphomyeloid tissues are the thymus, the spleen, the anterior part of the kidney, the meningeal myeloid tissue, the pericardial tissue and lymphoid masses of the intestine, especially in the spiral valve. The kidney is the main hemopoietic tissue. The meningeal tissue is bone marrow-like (myeloid), mainly granulopoietic, but it also contains lymphoid elements. The pericardial tissue is predominantly lymphoid. The pericardial tissue has a lymph node-like appearance. It seems to be the site of interaction between lymphocytes and vascular endothelium. The thymus contains cortex and medulla. The spleen, as in higher vertebrates, is differentiated into white and red pulp. The highly diversiform and well developed lymphoid tissues of sturgeons may serve as basis of efficient immune mechanisms.     

Characterization and Inhibition of Nitrite Uptake in Shortnose Sturgeon Fingerlings

Abstract

Efforts are underway to culture the endangered shortnose sturgeon Acipenser brevirostrum for possible reintroduction. As part of a larger project to develop culture techniques for this species, the uptake of nitrite was evaluated in fingerlings (16.5 ± 4.85 g; mean ± SD). Plasma nitrite concentrations increased significantly with exposure time (0–5 d) and dose (0–4 mg nitrite-N/L). Shortnose sturgeon fingerlings were able to concentrate nitrite in their plasma to more than 63 times the environmental concentration. Chloride, as either sodium chloride or calcium chloride, partially inhibited nitrite uptake. However, calcium chloride was a better inhibitor. After previous exposure (2 d at 2.13 ± 0.080 mg nitrite-N/L) plasma nitrite-N decreased from 165.5 to 36.7 mg/L during a 3-d simultaneous exposure to 2.13 ± 0.080 mg nitrite-N/L and treatment with 40 mg chloride/L as calcium chloride. The addition of calcium chloride to the water appeared to be an effective means of preventing nitrite uptake and treating nitrite toxicity in hatchery-reared shortnose sturgeon fingerlings.     

Pharmacokinetics and tissue residues of pefloxacin and its metabolite norfloxacin in broiler chickens

1. The pharmacokinetics of pefloxacin and its active metabolite norfloxacin were investigated in chickens after a single oral administration of pefloxacin at a dosage of 10 mg/kg. To characterise the residue pattern, another group of chickens was given 10 mg of pefloxacin/kg body once daily for 4 d by oral route; the tissue concentrations of pefloxacin and norfloxacin were determined at 1, 5 and 10 d after the last administration of the drug. 2. The concentrations of pefloxacin and norfloxacin in plasma and tissues were determined by HPLC assay. The limit of detection for pefloxacin and norfloxacin was 0.03 microg/ml in plasma or microg/g in tissue. 3. The plasma concentration-time data for pefloxacin and norfloxacin were characteristic of a one-compartment open model. The elimination half-life, maximum plasma drug concentration, time to reach maximum plasma drug concentration and mean residence time of pefloxacin were 8.74 +/- 1.48 h, 3.78 +/- 0.23 microg/ml, 3.33 +/- 0.21 h and 14.32 +/- 1.94 h, respectively, whereas the respective values of these variables for norfloxacin were 5.66 +/- 0.81 h, 0.80 +/- 0.07 microg/ml, 3.67 +/- 0.21 h and 14.44 +/- 0.97 h. 4. Pefloxacin was metabolised to norfloxacin to the extent of 22%. 5. The concentrations of pefloxacin (microg/g) 24 h after the fourth dose of the drug declined in the following order: liver (3.20 +/- 0.40) > muscle (1.42 +/- 0.18) > kidney (0.69 +/- 0.04) > skin and fat (0.06 +/- 0.02). Norfloxacin was also detectable in all the tissues analysed except muscle. No drug and/or its metabolite was detectable in tissues except skin and fat 5 d after the last administration. The concentrations of pefloxacin and norfloxacin in skin and fat 10 d after the last dose of pefloxacin were 0.04 +/- 0.02 and 0.03 +/- 0.01 microg/g, respectively.