过量人参皂苷对小鼠脑组织谷氨酸代谢的影响

目的:探讨过量人参皂苷对小鼠脑组织中谷氨酸代谢的影响。方法:常规饲养昆明小鼠,按照最终浓度低(8 mg/kg)、中(40mg/kg)、高(200 mg/kg)剂量连续灌胃人参皂苷24天,记录小鼠体重变化。第25天颈脱臼处死小鼠,取出全脑匀浆后测定谷氨酸水平,谷氨酰胺酶活力。结果:各实验组与对照组相比,体重明显下降;低、中、高实验组谷氨酸水平分别高与对照组13.66%、21.67%、39.83%,其中中剂量组和高剂量组显著高于空白组(P0.05);谷氨酰胺酶活力较对照组分别增高2.06%、2.91%、10.11%,高剂量与空白组差异显著,有统计学意义(P0.05)。结论:高剂量人参皂苷能使神经系统兴奋,可能与增高谷氨酰胺酶活力、从而提高脑组织中谷氨酸含量有关。     

流感病毒感染对小鼠肠道菌群的影响及桑叶的调节作用

【摘 要】 目的 探讨流感病毒对肠道菌群的影响以及桑叶提取物在治疗小鼠流感时对肠道菌群的调节作用。方法 将36只小鼠随机分为4组,正常对照组滴鼻生理盐水,其余以流感病毒鼠肺适应株FM1滴鼻3 d,建立流感小鼠模型后,正常对照组和病毒对照组灌胃生理盐水,另2组分别以高剂量(500 mg/kg)和低剂量(100 mg/kg)灌胃桑叶提取物,连续5 d。每天检测小鼠体重,并于病毒感染前、感染后及灌胃处理后3次无菌收集小鼠粪便,培养并计数小鼠粪便中肠杆菌、肠球菌、乳酸杆菌和双歧杆菌。结果 小鼠在感染病毒后体重明显降低,桑叶提取物治疗后体重降低的趋势有所减缓。小鼠肠道菌群在感染流感后有明显的变化,但桑叶提取物治疗后肠道菌群的恢复不明显。结论 流感病毒感染能引起小鼠肠道菌群的失调,桑叶不显示调节肠道菌群的效果,表明其对流感的治疗不通过调节肠道菌群平衡来发挥作用。     

薏米黄酒对机体免疫及肠道功能的调节作用研究

目的:考察薏米黄酒对机体免疫和肠道功能的调节作用。方法:将ICR小鼠随机分为3组:对照组、模型组和给药组。首先对模型组和给药组注射环磷酰胺造模,0.15 ml/d/只,连续3d,第4d开始对照组和模型组灌胃生理盐水0.3 ml/d/只,给药组灌胃薏米黄酒0.3 ml/d/只,连续灌胃14d。第1、4、18d对各组小鼠称重;第18d处死小鼠解剖取脾脏、胸腺称重并计算脏器系数;取肠道内容物做肠道微生物培养。结果:薏米黄酒与小鼠的体重变化无关;给药组脾脏系数高于对照组有统计学意义(P<0.05),胸腺系数高于对照组和模型组均有统计学意义(P<0.05);给药组细菌总数、大肠杆菌数和乳酸菌数高于模型组和对照组且有显著统计学意义(P<0.01),真菌数量低于模型组和对照组有统计学意义(P<0.05)。结论:该薏米黄酒对机体免疫和肠道功能有一定的调节作用。     

人参皂苷对 BALB/c 小鼠肠道菌群的影响

目的:随着人参药用和保健价值的不断发掘,人参皂苷引起人们越来越多的关注,但有关人参皂苷与肠道菌群之间相互作用的研究仍为空白领域,本实验旨在探明人参皂苷对小鼠肠道菌群的影响,以期为人参皂苷的推广应用提供理论基础和实验依据。方法:有机溶剂法提取人参皂苷,将正常BALB/c小鼠按2 mg/0.1 kg人参皂苷进行连续灌胃饲养,分别在灌胃第10 d和第13 d无菌收集小鼠粪便,提取肠道细菌基因组总DNA,应用PCR-DGGE技术获得肠道菌群分子指纹图谱,进行菌群结构相似性、多样性分析,并将感兴趣的优势条带进行切胶、测序分析,对获得的序列在Gene Bank数据库比对。结果:灌胃人参皂苷后小鼠肠道菌群结构发生改变,荧光假单胞菌和丁酸梭菌数量明显增加。结论:人参皂苷使小鼠肠道的菌群结构和数量发生明显改变,天然的人参皂苷口服很难被直接吸收利用,因此推测人参皂苷可能以肠道菌群作为发挥生物学作用的靶点,进而行使提高健康水平等保健功能。     

富硒双歧杆菌缓解5-FU导致的化疗性肠粘膜炎的药效学研究

通过腹腔注射5-FU建立小鼠肠黏膜炎模型,探讨富硒长双歧杆菌(Selenium-enriched Bifidobacterium longum,Se-B.longum)能否改善5-FU所致的小鼠肠黏膜炎。将健康BALB/c小鼠随机分为对照组、5-FU组和Se-B.longum/5-FU组,分别灌胃生理盐水、生理盐水和Se-B.longum(Se0.3 mg/kg BW,1×106bacteria/只)6 d,然后5-FU组和Se-B.longum/5-FU组小鼠均腹腔注射5-FU(250 mg/kg),观察小鼠腹泻及死亡情况,5 d后处死小鼠,计算体重变化、脏器指数及考察肠道组织变化;将健康BALB/c小鼠随机分为对照组、5-FU组和Se-B.longum/5-FU组,分别灌胃生理盐水、生理盐水和Se-B.longum(Se 0.3 mg/kg BW,1×106bacteria/只)6 d,然后5-FU组和Se-B.longum/5-FU组小鼠均腹腔注射5-FU(300 mg/kg),观察小鼠死亡情况,绘制生存曲线。Se-B.longum能缓解5-FU导致的正常小鼠的肠粘膜炎、降低小鼠死亡率。     

人参皂苷Rh_4对小鼠移植性肿瘤的抑制作用

本文阐述了三七中人参皂苷Rh4的体内抗肿瘤作用。建立S180肉瘤和肝癌H22荷瘤小鼠动物模型,将接种后的小鼠随机分为阴性对照组、阳性对照组及人参皂苷Rh4高、中、低剂量组,采用腹腔给药和灌胃给药两种方式,观察人参皂苷Rh4对小鼠移植性肿瘤的体内抑制作用以及对动物免疫器官重量的影响。结果表明:采用腹腔注射给药和灌胃给药,人参皂苷Rh4各剂量组对S180肉瘤小鼠和肝癌H22小鼠肿瘤生长均有抑制作用。与阴性对照组比较,当人参皂苷Rh4剂量为4.5 mg/kg灌胃给药时,对肉瘤S180的抑制率为47.84%(P0.01);当Rh4剂量为10.0 mg/kg腹腔注射给药时,对肝癌H22的抑制率为52.72%(P0.01)。人参皂苷Rh4对荷瘤小鼠免疫器官未见明显影响。     

土茯苓对高尿酸症小鼠肾损伤的防治作用

目的:观察土茯苓对高尿酸症小鼠肾功及血清尿酸的影响。方法:将昆明种小鼠分为正常对照组、模型对照组、土茯苓治疗组、别嘌呤醇治疗组,造模成功后分别给予土茯苓、别嘌呤醇灌胃,7d后检测各组大鼠血中肌酐(Cr),尿素氮(Bun)、尿酸(UA)及黄嘌呤氧化酶(XOD)。结果:治疗7d后,与模型组相比,土茯苓治疗组大鼠血肌酐、尿素氮、血UA、XOD明显降低(P<0.0 5)。结论:土茯苓对高尿酸症小鼠肾功能有保护作用,对尿酸升高有明显的治疗作用。     

基于16S rRNA测序分析两种呼肠孤病毒对小鼠肠道菌群的影响

目的 探究T1L和NBV两种呼肠孤病毒对小鼠肠道菌群结构的影响.方法 将25只小鼠随机分为5组(对照组、NBV滴鼻组、NBV灌胃组、T1L滴鼻组、T1L灌胃组),每组5只.对照组用PBS灌胃,其余组别均用2×107 PFU/mL病毒滴度感染小鼠.7 d后采集小鼠粪便,从每组5个样本中选出粪便重量较重的3个样本,对粪便D...     

分离自马奶及其制品中7株乳酸菌的安全性初步评价

【目的】通过小鼠的急性毒性、30 d喂养及细菌移位试验,对马奶及其制品(酸马奶)中分离出来的7株肠球菌属乳酸菌进行初步安全性评价。【方法】分别对小鼠连续7 d及30 d灌胃不同剂量的肠球菌JHZ9、JHZ15、JHZ17、JHZ22、JHZ25、JHZ28、JNN1,对其一般体征进行观察,记录体重和食物摄入量,最后进行大体解剖,观察肝、肾、脾、心、肺并称重,同时进行细菌移位试验。【结果】除30 d喂养中,试验菌株JHZ17的高剂量组与生理盐水组差异显著(P0.05),7 d急性毒性试验及30 d喂养试验中各试验组小鼠体重、食物摄入量与对照组相比无显著性差异(P0.05),30 d喂养后小鼠各脏器(心、肝、脾、肺、肾)指标与对照组无显著性差异(P0.05),小鼠的经口急性毒性最大耐受剂量(MTD)大于1010 CFU/(mL bw)20 mL/(kg·d),属无毒级别,未发现细菌移位现象。【结论】肠球菌JHZ9、JHZ15、JHZ17、JHZ22、JHZ25、JHZ28、JNN1安全,无毒副作用。     

红芪胶囊对低剂量辐射损伤小鼠的保护作用

目的:采用低剂量辐射损伤小鼠模型,观察红芪胶囊的药理作用。方法:二级昆明种小鼠216只,除正常组36只外,其余180只采用多次低剂量累积辐射。将照射的180只小鼠按体重随机分为5组,每组12只,分别为:模型组,阳性对照组(1.20 g/kg),红芪胶囊小剂量组(0.175 g/kg),红芪胶囊中剂量组(0.35 g/kg),红芪胶囊大剂量组(0.70 g/kg);将未照射的36只小鼠设为正常组,每组又分为给药6、12、24 d三个时间点,每时间点12只动物。各组在末次照射当天分别灌胃上述药物,正常对照组及模型对照组灌胃等量蒸馏水,每日一次,连续给药24 d,观察红芪胶囊的药理作用。结果:1红芪胶囊给药12 d、24 d对辐射损伤小鼠的外周血象红细胞(RBC)、白细胞(WBC)、血小板(PLT)和血红蛋白含量(HGB)有明显的升高作用(P0.01或P0.05);2明显增加辐射损伤小鼠的肝脏、脾脏、大脑和睾丸组织的湿质量(P0.01或P0.05);3镜下观察可见红芪胶囊能明显改善损伤小鼠骨髓细胞活性。结论:红芪胶囊对低剂量辐射损伤具有一定保护作用。     

不同剂量玛咖对力竭运动致大鼠运动性低血糖的保护作用

目的：探讨不同剂量玛咖对力竭运动致大鼠运动性低血糖的保护作用。方法：采用递增负荷力竭游泳训练的方法建立运动性低血糖动物模型。55只42 d龄雄性Wistar大鼠随机分为5组：①静止对照组（C组）,②运动对照组（M组）,③~⑤运动+低、中、高剂量玛咖组（LM I、LM Ⅱ,LM Ⅲ组）,每组10只（剔除不符合实验要求的大鼠5只）。每天灌胃（ig）1次,LM各组灌胃玛咖的剂量为0.2,0.4,1.2 g/kg体重,灌胃体积为5 ml/kg体重,C、M组灌胃等体积生理盐水。运动大鼠采用递增负荷力竭游泳训练42 d,42 d力竭游泳训练后,测定体重、力竭游泳时间,取血、肝脏及深层股四头肌检测相关生化指标。结果：与C组比较,M组体重、血糖水平、肌糖原与肝糖原含量、肝细胞磷酸烯醇式丙酮酸羧激酶（phosphoenol pyruvate carboxy kinase,PEPCK）表达、肝细胞阳性染色累计吸光度均值等均明显降低（P<0.05或P<0.01）;力竭游泳时间无明显差异;血乳酸含量明显升高（P<0.01）。与M组比较,LM各组体重、血糖水平、肌糖原与肝糖原含量、肝细胞PEPCK表达、肝细胞阳性染色累计吸光度均值等均明显升高（P<0.05或P<0.01）,力竭游泳时间明显延长（P<0.01）,血乳酸含量明显降低（P<0.01）。与LM I组比较,LMⅢ组体重无明显差异,LM Ⅲ组血糖水平、肌糖原与肝糖原含量、肝细胞PEPCK表达、肝细胞阳性染色累计吸光度均值等均明显升高（P<0.05）,力竭游泳时间明显延长,血乳酸含量明显降低（P<0.05）。结论：高剂量玛咖可有效抑制和延缓长时间、大负荷运动导致的运动性低血糖和运动性疲劳的发生与发展,其机制可能与优化肌糖原和肝糖原的储备量及上调糖异生限速酶PEPCK的表达,提高PEPCK活性,促进糖异生有关。     

γ-氨基丁酸茶对小鼠抗疲劳作用的研究

目的:研究γ-氨基丁酸茶对小鼠的抗疲劳作用.方法:采用昆明种小鼠游泳力竭实验,实验动物分为γ-氨基丁酸茶高、中和低实验组及空白对照组,分别检测游泳力竭时间,测定小鼠血糖、肝糖原、肌糖原,血清BUN、LDH、CK、SOD、MDA、GSH-PX,以及游泳前后的血乳酸.结果:γ-氨基丁酸茶对小鼠的实验期间的体重无明显影响.力...     

Interaction of thyroxine,energy metabolism and swimming performance of rats

Time required for exhaustive swimming by young-mature rats weighted with lead weights (4% of body weight) was found to decline over a ten week experimental period. While a positive relationship existed between thyroid status and swimming time, a concomitant decrease in swimming time occurred in each of the respective five groups of rats: control (C) rats with intact thyroids, athyroid (A-Tdx), hypothyroid (Hypo-Tdx), euthyroid (Eu-Tdx), and hyperthyroid (Hyper-Tdx) rats between day 70–140. The latter three groups were thyroidectomized (Tdx) and given daily replacement therapy of L-thyroxine (L-T₄) during the experimental period. Epididymal fat pads were found to be almost non-existent in the A-Tdx rats. Serum triglycerides of A-Tdx, Eu-Tdx, and Hypo-Tdx animals were significantly lower than in C. Daily food intakes were also lower in the A-Tdx and Hypo-Tdx groups than in C and Hyper-Tdx groups. Thyroxine insufficiency, the decreasing feed intake, and particularly the ability to carry the increasing absolute weight load during exercise are factors that may be important in explaining the observed decline in work capacity during the ten week experimental period.     

水温和体重对白斑红点鲑临界游泳速度和游动耗氧率的影响

为了揭示水温和体重对白斑红点鲑(Salvelinus leucomaenis)临界游泳速度和游动耗氧率的影响, 利用试验生态学方法测定了不同体重(1龄组、2龄组和3龄组)的白斑红点鲑在4、8、12、16、20和24℃共6个水温的临界游泳速度和游泳耗氧率。结果表明: 水温和体重对临界游泳速度的单独效应均显著(P0.05), 但水温和体重交互作用效应却不显著(P0.05), 在相同水温下白斑红点鲑临界游泳速度均随着年龄的增长(体重增加)而增加。水温4℃时3个年龄组白斑红点鲑临界游泳速度均最低, 分别为(21.61.06)、(22.930.61)和(30.271.29) cm/s, 随着水温的升高临界游泳速度均不断增加, 当水温升高到16℃时临界游泳速度达到最大值, 分别为(39.60.80)、(46.800.80)和(53.731.22) cm/s, 此后随着水温进一步升高到20℃, 临界游泳速度虽出现略微降低, 但经统计分析16℃和20℃时临界游泳速度无显著性差异(P0.05), 当水温达到24℃时却出现明显降低。水温和流速以及二者的交互作用对游泳耗氧率的影响均达到显著水平(P0.05), 白斑红点鲑在适宜的相同水温和流速时体重越大其游泳耗氧率越低, 整体观察3个年龄组白斑红点鲑鲑游泳耗氧率均随着水温和流速的增高而增高, 但当水温和流速升高到一定值游泳耗氧率却出现降低。研究得出体重较大的个体在相同水温下抵抗水流的游泳能力较强, 3个年龄组白斑红点鲑适宜的最高水温不应超过20℃, 最高流速依次不应超过32、40和48 cm/s。       

玛咖提取物对运动耐力和脊神经元线粒体超微结构的影响

目的：探索玛咖提取物对运动耐力和脊神经元线粒体超微结构的影响。方法：50只Wistar大鼠随机分为5组。对照组：不进行游泳,灌胃等量蒸馏水;单纯游泳组：游泳,灌胃等量蒸馏水,玛咖提取物组（设4.0,5.3,8.0 g/kg 3个剂量组）：游泳,给予相应剂量的玛咖提取物。游泳大鼠在游泳池内循环水流自由游泳,连续游泳并给药15 d,第16天游泳耐力测试后无痛处死大鼠,用投射电子显微镜观察脊髓神经元线粒体超微结构,放免法测定肌肉肌糖元、检测肌肉中丙二醛（MDA）、超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）和游离钙水平。结果：与单纯游泳组比,沉下前游泳时间和游泳总时间分别延长了（%）19.83、60.28、77.55和55.34、73.91、94.47,差异均有统计学意义（P均<0.01）;沉下次数分别减少了（%）34.35、51.18、57.96,差异有统计学意义（P<0.01）;MDA和游离钙含量分别降低了（%）20.10、31.49、38.72,差异有统计学意义（P<0.01）和6.42、17.58、26.35;SOD、GSH-Px和肌糖原含量分别升高了（%）5.12、22.74、52.53、44.22、77.79、98.45,差异有统计学意义（P<0.01）和35.08、47.83、81.88,差异有统计学意义（P<0.01）;脊神经元线粒体的体密度（VD）、面密度（SD）和数密度（ND）分别减小了（%）7.79、18.18、31.17,16.95、27.34、43.31和13.51、23.19、43.15。结论：玛咖提取物具有保护脊髓神经元线粒体结构、抗氧化、增加肌糖原和提高运动能力等作用。     

Effects of feeding on medicinal leech swimming performance

The locomotor system of sanguivorous leeches is presented with a unique challenge: how to maintain mobility while coping with a >500% increase in body mass during feeding. A meal of this size is likely to disrupt the function of the muscular hydrostat during swimming, reducing speed and increasing predation risks. We quantified the effects of feeding to satiety on swimming kinematics, and the time course of recovery of swimming performance post-feeding in the medicinal leech Hirudo verbana . There was a 5.07 ± 0.04-fold increase in mass during feeding (mean ± sem , n =7). Despite this, leeches were able to swim immediately after feeding, reaching 27% of their pre-feeding speed. Reduced speed was a consequence of a reduction in both swimming cycle frequency and stride length to 69 and 42% of the pre-feeding values, respectively. Recovery of swimming ability was rapid, despite a prolonged increase in body mass. Fifty per cent restoration of swimming speed was achieved in c . 1 h while body mass was still 4.2-fold greater than before feeding. Rapid mass and volume reduction immediately post-feeding, and the properties of the obliquely striated swimming muscles appear to aid recovery of swimming performance. Such features that aid post-feeding recovery of mobility may have been important in the evolution of leech sanguivory.     

Determination of the energetic cost of swimming from the analysis of growth rate and body composition in juvenile chinook salmon, Oncorhynchus tshawytscha

The standard metabolic rate was estimated to be 19.5 cal X kcal-1 X day-1. The multiple regression of growth on swimming speed and ration size was significant (P less than 0.001). The relationship was as follows: G = 22.22-2.85BL + 6.58 R where G is growth in cal X kcal X day-1, BL represents swimming speed in body lengths X sec-1 and R denotes ration in % body wt X day-1, dry weight. The multiple correlation coefficient, R2, was 0.80. Unlike coho salmon, the net cost of swimming was independent of swimming speed. Fish in all groups experienced reduction of fat with exercise with the exception of the slowest speed-highest ration (1.0-1.9 BL X sec-1, 6% X day-1) group. Nearly all of the explained variation was accounted for by food consumption rate.     

Overexpression of actin-depolymerizing factor blocks oxidized low-density lipoprotein-induced mouse brain microvascular endothelial cell barrier dysfunction

This study was designed to evaluate the anti-inflammatory and anti-apoptotic effects of the alcoholic extract of the berries of Crataegus oxyacantha (AEC), a medicinal herb, on isoproterenol-induced myocardial infarction (MI) in a rat model. Three groups of Wistar albino rats, each comprising six animals, were selected for this study. Group I rats served as control. Group II rats were given isoproterenol (85 mg/kg body weight) subcutaneously on 59th and 60th days. Group III rats were given AEC (0.5 ml/100 g body weight/day), orally on a daily basis for 60 days, and isoproterenol (85 mg/kg body weight, subcutaneously) was given on 59th and 60th days. On the 61st day, the animals were sacrificed, and marker enzymes like lactate dehydrogenase (LDH) and creatine kinase (CK) were estimated in serum. In the heart tissue sample, antioxidant status, lipid peroxidation and anti-inflammatory properties of AEC were determined. Isoproterenol significantly increased the release of LDH, CK in serum, decreased the antioxidant status in the heart along with an increase in lipid peroxidation. Nitritive stress and apoptosis were seen in isoproterenol-induced rat heart. Pre-treatment with the AEC for 60 days had a significant effect on all the above factors and maintained near normal status. The study confirms the protective effect of AEC against isoproterenol-induced inflammation and apoptosis-associated MI in rats.     

辣木叶黄精多糖组合物的抗疲劳作用及其机制研究*

目的: 探讨辣木叶黄精多糖组合物的抗疲劳作用,并探讨相关的机制。方法: 将30只雄性昆明小鼠随机分为正常对照组(C)、组合物组(MP),每组15只。C组灌胃蒸馏水,MP组灌胃组合物,每组灌胃体积均为0.5 ml。每日灌胃,处理14 d后进行负重游泳实验,按小鼠体质量的3%进行尾部负重,记录力竭游泳时间。在另一项实验中,将48只雄性昆明小鼠随机分为安静对照组(QC)、游泳对照组(SC)、组合物组(MP),每组16只。QC和SC组灌胃蒸馏水,MP组灌胃组合物,灌胃体积均为0.5 ml,每日灌胃,处理14 d。实验第15日,灌胃30 min后,QC组立即取血、肝脏和后腿骨骼肌;SC和MP组进行90 min非负重游泳实验,游泳结束后取血液、肝脏、后腿骨骼肌。采用试剂盒测定血清、组织中的疲劳相关指标、氧化/抗氧化指标、能量代谢指标。结果: MP组小鼠力竭游泳时间较C组显著延长(P<0.05)。与对照组比较,非负重游泳显著降低小鼠血糖和血清谷胱甘肽(GSH)水平、肝糖原和肝脏ATP含量,抑制肝脏超氧化物歧化酶(SOD)、乳酸脱氢酶(LDH)和ATP酶活性,以及肌肉谷胱甘肽过氧化物酶(GSH-Px)活性(P<0.05)。而血尿素氮(BUN)和血清丙二醛(MDA)水平显著升高(P<0.05)。与SC组比较,MP显著增加小鼠血糖和肝糖原含量,增加血清GSH水平、肝脏SOD活性、肌肉GSH-Px活性,增强肝脏LDH、ATP酶活性,增加肝脏ATP含量(P<0.05),降低血清BUN(P<0.05)。结论: 辣木叶黄精多糖组合物具有抗疲劳作用,抗氧化和改善能量代谢可能是其发挥作用的重要机制。     

Physiological and Endocrinological Responses During Prolonged Exercise in Hatchery-Reared Rainbow Trout (Oncorhynchus mykiss)

Rainbow trout (Oncorhynchus mykiss) were subjected to vigorous exercise (1.5 body length s−1), low exercise (0.5 body length s−1) or still-water (0.0 body length s−1). Hematocrit, glucose, growth hormone (GH), Cortisol and triiodo-L-thyronine (T3) were monitored at the start of exercise, after 24 h, and after 2, 4, 8, 16 and 32 days of continuous swimming. Morphological indices and food intake were also monitored. At the end of the experiment, trout subjected to low exercise had gained significantly (p<0.05) more weight than both the control (still-water) and vigorously exercised fish. This low exercised group of fish also consumed more food than the 2 other groups. Hematocrit increased significantly in both exercised groups at the onset of swimming but returned to pre-exercise levels within 8 hrs. Plasma glucose appeared to be generally unaffected by exercise. Likewise, plasma concentrations of both GH and T3 were not influenced by exercise. Plasma Cortisol levels increased in an exercise dependent fashion at the onset of swimming, but returned to pre-swimming levels within 24 h and there was no apparent effect of sustained swimming. The results suggest: (i) the onset of exercise elicits transient changes in plasma components, (ii) the observed weight gain in low exercising salmonids occur without increases in circulating levels of GH or T3.