饥饿和再投喂对鲇血液生理生化指标的影响

在室内可控条件下,对鲇（Silurus asotusLinnaeus）进行7d、14d和21d的饥饿处理,随后各组恢复投喂20d,研究饥饿和再投喂对鲇血液生理生化指标的影响。结果显示：饥饿过程中,鲇血液红细胞数和血红蛋白14d内上升,血红蛋白上升显著（p〈0.05）,21d后两项生理指标开始下降;饥饿7d后血糖浓度显著下降（p〈0.05）,饥饿14d和21d后趋于相对稳定;总蛋白、白蛋白和球蛋白均呈下降趋势,分别在饥饿的14d、7d和21d后与饥饿前达到显著性差异（p〈0.05）;甘油三酯和总胆固醇分别在饥饿7d和21d后显著下降（p〈0.05）;饥饿14d后Na＋和Cl-浓度显著下降（p〈0.05）,21d后Na＋浓度却又显著上升（p〈0.05）,Cl-浓度有所回升;Ca2＋浓度在饥饿过程中逐渐下降,且差异显著（p〈0.05）。饥饿对K＋浓度和碱性磷酸酶活力没有明显影响。恢复投喂20d后,测定的血液指标均有不同程度的恢复。采用二元三次方程（CUB类型）就各项生理生化指标对饥饿时间（d）进行的回归分析表明,Ca2＋与饥饿时间的决定系数（R2）最大,为0.964,因此将鲇血液的Ca2＋浓度作为其饥饿的评价指标则相对可信。     

日本沼虾继饥饿后补偿生长研究

在25.0±1℃条件下,对日本沼虾Macrobrachium nipponense (湿重, 0.52～0.64 g )进行了不同时间的饥饿处理后再供食的恢复生长实验.对照组C连续饱食投喂18 d;处理组S2、S4和S8分别饥饿2、4和8 d后再饱食投喂16、14和10 d.结果 饥饿结束时各处理组的湿重均显著低于对照组;实验结束时S2、S4组与对照组间的湿重差异不显著,而S8组的湿重仍显著低于对照组;恢复生长时各处理组的湿重摄食率、食物转化率和生长率开始显著高于对照组,但随着恢复时间延长又逐步达到对照组水平.随着饥饿时间延长,日本沼虾标准代谢率降低.在恢复投喂后又逐步回升到对照组水平.实验结果表明,日本沼虾继饥饿后再恢复喂食出现完全或部分补偿生长效应不仅是由于增加食欲,提高了摄食水平,同时也改善了食物转化率.因此,补偿生长是这两种生理因素共同作用的结果.     

限食和再恢复投喂对鲮鱼生化组成的影响

在水温 19℃— 2 4℃条件下对鲮鱼 (初始体重 :88 86± 5 92g)进行了不同时间的限食处理后再充分投喂的恢复生长实验。结果表明 :限食状态下 ,肝脏糖原 ,肝脏脂肪和肌肉 (白肌 )糖原含量均显著降低 ;肝脏和肌肉水含量显著升高 :而肌肉脂肪 ,肝脏蛋白和肌肉蛋白变化都不显著 ;血糖 ,血脂和血浆蛋白含量都显著降低。再充分投喂后 ,各生化成分均恢复到对照组水平 ,表明鲮鱼在恢复生长过程中产生了显著的补偿效应     

饥饿对大鳞副泥鳅不同组织糖原、ACP和ALP的影响

饥饿是鱼类在自然状况下经常遇到的不良条件,此时鱼类体内会发生各种生理变化以适应逆境.本文以大鳞副泥鳅为材料,研究了饥饿和再投喂过程中,肝和肌肉两种组织中糖原、酸性磷酸酶和碱性磷酸酶的细胞化学特征.对大鳞副泥鳅进行饥饿处理,0～28 d不喂养食物,29～35 d恢复正常喂食.分别于0、7、14、21、28和35 d取材检测.结果表明,随着饥饿程度的加深,糖原和ACP的量均减少,ALP则增多.投喂后,都有不同程度的恢复.但变化存在组织差异.糖原的含量可作为鱼类饥饿程度和补偿性生长的一个重要指标,ACP和ALP在鱼类的应激反应中具有重要作用.     

饥饿对银鲫血液组分和卵巢发育的影响

对银鲫 (Carassiusauratusgibelio)进行投喂、饥饿 (1～ 4周 )、饥饿投喂 (饥饿 2周再投喂 2周 )处理后 ,测定其血液组分和卵巢发育的指标。结果表明 :饥饿处理后银鲫血液中血糖、甘油三酯的含量显著降低 ;红细胞数量、血红蛋白含量和胆固醇含量先显著降低 ,随后回升到投喂组水平 ;在饥饿过程中白细胞的数量、红细胞的长短径、红细胞沉降率和总蛋白均无明显变化。饥饿投喂处理的银鲫血液中红细胞数量、甘油三酯和胆固醇含量与投喂组无差异 ,但血糖含量仍显著低于投喂组 ,而白细胞数和血红蛋白含量显著高于投喂组。饥饿 4周延缓了银鲫卵巢发育 ,其性腺成熟系数和卵径均显著低于投喂组 ;饥饿投喂组的性腺成熟系数和卵径仍显著低于投喂组。分析说明饥饿阻碍了银鲫的卵巢发育 ,而饥饿对银鲫血液组分的影响在再投喂后得到恢复。     

补偿生长对异育银鲫IGF-1、IGFBP-1水平及IGF-1、IGF-1RmRNA表达的影响

该实验分析饥饿和恢复投喂对异育银鲫血液IGF-1和IGFBP-1水平和肝脏IGF-1、白肌IGF-1RmRNA表达量的影响。结果显示:饥饿期(14d)血液中IGF-1和IGFBP-1水平逐渐下降,在饥饿第14天均出现显著性降低(P<0.05);恢复投喂后第1天IGF-1迅速恢复到对照组水平,而IGFBP-1水平仍显著低于对照组(P<0.05),随后逐渐升高,直至于恢复投喂第14天后显著高于对照组水平(P<0.05);饥饿期肝脏IGF-1mRNA表达量呈下降趋势,但与对照组无显著性差异(P>0.05);恢复投喂初期(第1、3天),IGF-1mRNA表达量仍继续下降(P<0.05),对营养条件的变化反应滞后,至第7天,表达水平恢复到对照组水平。白肌IGF-1RmRNA表达水平在饥饿第3天出现显著性下降(P<0.05),继续饥饿其水平出现补偿性升高;恢复投喂后第14天IGF-1RmRNA表达量显著高于对照组水平(P<0.05)。该结果揭示恢复投喂期高水平的IGFBP-1含量和IGF-1RmRNA表达量可能通过提高IGF-1的促生长作用参与异育银鲫的补偿生长调节。     

补偿生长对中国林蛙肝脏生化组成的影响

在室内环境条件下研究了不同饥饿程度和再投喂后中国林蛙肝脏中蛋白质、糖原和脂肪含量的变化,并对中国林蛙在补偿生长过程中能量来源的变化进行了分析.结果 表明,饥饿状态下,中国林蛙的能量消耗主要来源于肝糖原,其次是蛋白质,即饥饿时中国林蛙首先动用糖原和蛋白质提供能量.     

饲喂蚕豆对草鱼抗氧化能力及免疫机能的影响

投喂蚕豆100d左右, 草鱼肌肉的弹性和咀嚼性增强, 肌肉品质显著改善, 此种模式养殖的草鱼俗称脆肉鲩。实验比较了投喂蚕豆与商用配合饲料的草鱼, 在养殖过程中(30d、60d、100d)机体抗氧化能力及免疫机能的异同, 以了解脆肉鲩肌肉品质改变过程中鱼体的生物学变化。实验结果表明, 投喂蚕豆显著影响了草鱼血清总抗氧化能力(T-AOC)、血清丙二醛(MDA)含量及肝胰脏超氧化物歧化酶(SOD)活力, 但对肝胰脏T-AOC、MDA含量、谷胱甘肽(GSH)含量及血清SOD活力无显著影响。实验30d和60d时, 投喂蚕豆的草鱼机体抗氧化能力强于投喂配合饲料的草鱼, 但实验100d时两种养殖模式的草鱼机体抗氧化能力无显著差异。投喂蚕豆对草鱼免疫机能有一定的影响, 实验100d时, 投喂蚕豆的草鱼血液红细胞数量(RBC)及白细胞数量(WBC)显著高于投喂配合饲料的草鱼。投喂蚕豆的草鱼血清TP、ALB、GLB含量在实验30d时显著低于投喂配合饲料的草鱼, 在实验60d时与投喂配合饲料的草鱼无显著差异, 在实验100d时又显著低于投喂配合饲料的草鱼。投喂蚕豆显著影响了草鱼脾指数及脾脏中免疫相关基因的表达, 实验末期, 在投喂蚕豆的草鱼脾脏中IL-1、MHC Ⅱ、IFN-1、TNF-的表达量显著高于投喂配合饲料的草鱼。以上结果表明, 投喂蚕豆初期鱼体抗氧化能力增强, 随着投喂时间的增加, 鱼体抗氧化能力降低至与投喂配合饲料相当的水平; 投喂蚕豆使草鱼产生了免疫应答。       

草鱼Isthmin-1基因序列分析及转录水平的营养调控

为探讨Isthmin-1(Ism-1)在草鱼糖和脂类代谢中的作用,研究采用RT-PCR技术克隆草鱼Ism-1的开放阅读框(ORF),生物信息学分析Ism-1及其编码的氨基酸序列, RT-qPCR技术检测Ism-1在草鱼各组织中的分布特点,并在细胞和活体水平上分析不同营养条件下Ism-1 mRNA的表达变化。结果显示,成功克隆草鱼Ism-1的ORF区。序列分析表明,草鱼Ism-1基因开放读码框为1380 bp,编码459个氨基酸,预测该蛋白相对分子量为50.96 kD。氨基酸多序列比对和系统进化树分析显示,草鱼Ism-1与黑头软口鲦(Pimephales promelas)的进化关系最近(氨基酸相似度为96.51%)。Ism-1在草鱼各组织中均有表达,在红肌中表达量最高,其次是鳃、脑和白肌等组织。饥饿再投喂实验结果表明,饥饿14d后肝胰脏中Ism-1的表达量显著上调(P<0.05),恢复投喂后表达量降低,但仍显著高于对照组(P<0.05),白肌中Ism-1的表达量在饥饿和再投喂后均显著增加(P<0.05)。腹腔注射不同浓度的胰高血糖素显著下调草鱼肝胰脏中Ism-1的mR...     

淡水养殖太平洋鲑循环饥饿后补偿性生长效果研究

用16.1%脂肪,38.1%蛋白质含量日粮饲养108尾初始重约为240g的太平洋鲑(Oncorhynchusspp.)于0.25m3的水族箱中64d,水温为15.5±3.7℃。实验分6组,分别为对照组(每天投喂),实验1组(隔天投喂),实验2组(隔2天投喂2天),实验3组(隔4天投喂4天),实验4组(隔8天投喂8天),实验5组(隔16天投喂16天)。每组设3个平行水族箱,每箱6尾鱼。研究淡水养殖太平洋鲑多重周期饥饿后补偿性生长效果。实验结果表明:(1)各试验组太平洋鲑成活率均为100%。实验1、2、3组太平洋鲑鱼体增重接近对照组,其恢复摄食期间特定生长率、摄食率、食物转化率均显著或极显著高于对照组(P<0.05或0.01)。而实验4、5组鱼恢复摄食期间虽摄食率极显著高于对照组(P<0.01),但其鱼体增重、特定生长率、食物转化率均极显著低于对照组(P<0.01);(2)实验各组鱼肥满度、肝体比、肝脏脂肪和糖原含量、肌肉中脂肪含量较对照组均有不同程度下降,肝脏脂肪中总饱和脂肪酸比例上升,而总多不饱和脂肪酸比例下降;(3)实验1、2、3组血浆中甘油三酯、胆固醇和低密度脂蛋白显著低于对照组,而葡萄糖、血清中甲状腺激素T4浓度显著高于对照组(P<0.05)。实验结果表明,初重约240g太平洋鲑饥饿1—4d,再循环投喂相同时间64d后,获得了接近完全补偿生长效果,表现为其恢复摄食期间摄食率和食物转化率明显上升,生长速率明显加快,饲料报酬明显提高,鱼体增重接近持续喂食的对照组,养殖效益明显提高。但饥饿8—16d再循环投喂相同时间后,表现为无补偿生长效应,食物转化率和生长速率明显下降,鱼体增重极显著低于持续喂鱼的对照组。     

Hepatopancreas gluconeogenesis and glycogen content during fasting in crabs previously maintained on a high-protein or carbohydrate-rich diet

The present study assessed the effect of different fasting times on the in vitro gluconeogenic capacity of Chasmagnathus granulata crabs previously adapted to a high-protein (HP) or carbohydrate-rich (HC) diet using the incorporation of [U-(14)C]l-lactate or [U-(14)C]l-alanine into glucose. We also recorded haemolymphatic glucose and hepatopancreatic glycogen levels. In the HP group, on the third day of fasting there were decreases in the synthesis of glucose from (14)C-alanine and in haemolymph glucose. After 15 days of fasting, haemolymph glucose and hepatopancreatic glycogen levels were maintained by an increase in the conversion of (14)C-alanine into glucose. However, after 21 days of fasting the gluconeogenic capacity was decreased and hepatopancreas glycogen concentration was reduced. In the HC group, hepatopancreatic glycogen was the energy source during the first 6 days of fasting. Gluconeogenesis from (14)C-lactate decreased after 6 days of fasting, remaining low until 21 days of fasting. The conversion of (14)C-alanine into glucose was increased after 15 days fasting and hepatopancreatic glycogen was raised in relation to that present after a 6-day fasting. In both dietary groups the stabilization in the levels of haemolymph glucose after 21 days fasting may result from a reduction in metabolic rate during restricted feeding.     

Carcass glycogen repletion on carbohydrate re-feeding after starvation.

In mice, the response of carcass glycogen to glucose re-feeding after starvation is biphasic. The initial repletive phase is followed by partial (greater than 50%) glycogen mobilization. This turnover of carcass glycogen in response to carbohydrate re-feeding may play an important role in the provision of C3 precursors for hepatic glycogen synthesis.     

Mobilization of copper among tissues in the estuarine crab Scylla serrata (Forskal) under imposed starvation

The quantitative changes in copper free and bound to proteins in haemolymph and different forms of copper in muscle and hepatopancreas under imposed starvation were studied in the estuarine mud crab Scylla serrata. During the course of starvation, both haemolymph copper free and bound to proteins significantly declined and the regression analyses of these data further revealed that the haemolymph copper-free proteins were more affected than copper-bound proteins. The multiple stress condition namely injury and exsanguination along with starvation resulted in an earlier release and/or degradation of both these proteins. Hepatopancreas periodically accumulates and releases copper during starvation. The copper levels in haemolymph and hepatopancreas during different days of starvation showed a close inverse relationship between these two tissues. These changes in hepatopancreas were predominantly reflected in the copper that exists in association with low molecular weight substances. It is found that the copper thus accumulated was partly released back into haemolymph and a fraction may be excreted. This study also indicates the major role played by the low molecular weight substances in accommodation, detoxification and mobilization of copper in the decapod hepatopancreas during imposed starvation.     

Skeletal-muscle glycogen synthesis during the starved-to-fed transition in the rat.

The pattern of glycogen deposition in skeletal muscles of varying fibre composition was examined in rats during the starved-to-fed transition. In all the muscles studied, glycogen concentrations steadily increased during the first 8 h after chow re-feeding, and the fed value was exceeded. Rates of glycogen deposition varied, not with muscle fibre composition, but with the extent of glycogen depletion during starvation. There was no evidence for skeletal-muscle glycogen breakdown during the period of hepatic glycogenesis, making it unlikely that recycling of carbon from muscle glycogen to lactate is quantitatively important for the provision of glycogenic precursors to the liver, but moderate glycogen loss was observed from 8 to 24 h after re-feeding, when the liver is in the lipogenic mode. The factors influencing glucose disposal by skeletal muscle after re-feeding are discussed.     

Energy reserves during food deprivation and compensatory growth in juvenile roach: the importance of season and temperature

The effect of 21 days of starvation, followed by a period of compensatory growth during refeeding, was studied in juvenile roach Rutilus rutilus during winter and summer, at 4, 20 and 27° C acclimation temperature and at a constant photoperiod (12L : 12D). Although light conditions were the same during summer and winter experiments and fish were acclimated to the same temperatures, there were significant differences in a range of variables between summer and winter. Generally winter fish were better prepared to face starvation than summer fish, especially when acclimated at a realistic cold season water temperature of 4° C. In winter, the cold acclimated fish had a two to three‐fold larger relative liver size with an approximately double fractional lipid content, in comparison to summer animals at the same temperature. Their white muscle protein and glycogen concentration, but not their lipid content, were significantly higher. Season, independent of photoperiod or reproductive cycle, was therefore an important factor that determined the physiological status of the animal, and should generally be taken into account when fish are acclimated to different temperature regimes. There were no significant differences between seasons with respect to growth. Juvenile roach showed compensatory growth at all three acclimation temperatures with maximal rates of compensatory growth at 27° C. The replenishment of body energy stores, which were utilized during the starvation period, was responsible for the observed mass gain at 4° C. The contribution of the different energy resources (protein, glycogen and lipid) was dependent on acclimation temperature. In 20 and 27° C acclimated roach, the energetic needs during food deprivation were met by metabolizing white muscle energy stores. While the concentration of white muscle glycogen had decreased after the fasting period, the concentrations of white muscle lipid and protein remained more or less constant. The mobilization of protein and fat was revealed by the reduced size of the muscle after fasting, which was reflected in a decrease in condition factor. At 20° C, liver lipids and glycogen were mobilized, which caused a decrease both in the relative liver size and in the concentration of these substrates. Liver size was also decreased after fasting in the 4° C acclimated fish, but the substrate concentrations remained stable. This experimental group additionally utilized white muscle glycogen during food deprivation. Almost all measured variables were back at the control level within 7 days of refeeding.     

Effects of starvation on haemolymphatic glucose levels, glycogen contents and nucleotidase activities in different tissues of Helix aspersa (Müller, 1774) (Mollusca, Gastropoda)

In the present study, the glucose concentration in the haemolymph and glycogen levels were determined in the various body parts of the Helix aspersa snail after feeding lettuce ad libitum and after various periods of starvation. To characterize the effect of starvation on nucleotidase activity, enzyme assays were performed on membranes of the nervous ganglia and digestive gland. Results demonstrated the maintenance of the haemolymph glucose concentration for up to 30 days of starvation, probably due to the consumption of glycogen from the mantle. In the nervous ganglia, depletion of glycogen occurs progressively during the different periods of starvation. No significant changes were observed on ATP and ADP hydrolysis in the membranes of nervous ganglia and no alterations in Ca2+ -ATPase and Mg2+ -ATPase occurred in the membranes of the digestive gland of H. aspersa during the different periods of starvation. Although there were no changes in the enzyme activities during starvation, they could be modulated by effectors in situ with concomitant changes in products/reactants during starvation.     

Changes in plasma thyroxine,triiodothyronine and cortisol associated with starvation in rainbow trout (Salmo gairdneri)

Synopsis Chronically starved rainbow trout (Salmo gairdneri) showed a significant fall in liver size, total liver glycogen, liver glycogen concentration and plasma glucose levels. Liver lipid concentration did not differ significantly from controls although total liver lipid reserves fell during the first 40 days of starvation but had partly recovered after 65 days of starvation. Plasma cortisol and T3 levels did not show consistent changes concomitant with food deprivation over the 65 day period of the experiment. However, plasma T4 levels in fish starved for 40 or 65 days were significantly lower than comparably fed animals. The involvement of T4 in intermediate metabolic processes in salmonids is discussed.     

Hyperglycaemic effects of 5-hydroxytryptamine and dopamine in the freshwater prawn, Macrobrachium malcolmsonii

The effects of 5-hydroxytryptamine (5-HT; serotonin) and dopamine (DA) on tissue carbohydrate metabolism and haemolymph glucose levels in the freshwater prawn, Macrobrachium malcolmsonii, were investigated. Injection of 5-HT and DA produced hyperglycaemia in a dose-dependent and time-dependent manner, with DA being more effective than 5-HT. Interestingly, 5-HT and DA induced hyperglycaemia only in intact prawns but not in bilaterally eyestalk-ablated individuals. Total carbohydrate (TCHO) and glycogen levels decreased and phosphorylase activity increased in the hepatopancreas and muscle of intact prawns after being injected with 5-HT or DA. However, bilateral eyestalk ablation decreased haemolymph glucose and tissue phosphorylase activity and increased TCHO and glycogen levels of the hepatopancreas and muscle. Injection of 5-HT or DA did not cause significant changes in these variables in eyestalk-ablated prawns. It is hypothesized that 5-HT and DA induce hyperglycaemia in prawns by stimulating the release of crustacean hyperglycaemic hormone (CHH) from the X-organ sinus gland (XO-SG) complex located in the eyestalk.     

Effects of stress on carbohydrate metabolism in the teleost Notopterus notopterus (Pallas)*

The effects of different types of stre35 on carbohydrate metabolism in N. notopterus were investigated. Starvation alone brings about a signifiant increse in the glycogen content of the saccus vasculosus and a significant decrease in the brain glycogen concentration. The increased glycogen concentration in the saccus vasculosus may be a device to safeguard the brain against glucose deficiency during starvation stress. Rapid depletion of the muscle glycogen following fasting shows that the muscle glycogen IS the readily utilizable source of energy during starvation. Exposure of N. noropierus to air brought about an increaSe in the liver glycogen and blood glucose levels but did not affect other paramcters studied. Physical exhaustion of N. notopierus is noticed within 1–2 min of exercise. The readily available source of energy for exercise is the muscle glycogen. and the lactic acid produced is probably metabolized in the muscle itself. Saccus vasculosus glycogen. though inde-pendent of changes in the blood glucose levels, may possibly be controlled by variations in the brain glycogen.