摘要:

Glucose and lactate kinetics were examined in fed and food‐deprived American eels,Anguilla rostrata(LeSueur), under MS 222 anaesthesia (AE). These values are compared to free‐swimming, non‐anaesthetized animals (FSE) reported previously (Cornish&Moon, 1985). The AE group demonstrated a steady but minor hyperglycemia during the 5‐h experiment and significant decreases in both glucose turnover and metabolic clearance rates compared to the FSE groups. Food‐deprivation further depressed these kinetic parameters.Blood lactate continuously increased during the experiment, reaching values 300 times (fed) and 100 times (food‐deprived) higher than the similar FSE groups. Consistent with these higher concentrations, rates of lactate appearance in and disappearance from the blood generally increased with anaesthesia.This study supports the view of Soivioet at.(1977) that MS 222 acts as an asphyxiant. The associated metabolic disruptions are consistent with a reduction in oxidative in favour of anaerobic tissue metabolism. The specific changes in glucose and lactate parameters reflect the nervous and hormonal disruptions occurring with anaesthesia. These studies urge caution in the interpretation of data using an anaesthetized fish

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1986.tb05135.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Two hundred specimens of the cyprinid fishPuntius binotatuswere collected over a period of 1 year, February 1976–January 1977, from an irrigation canal in Palau Pinang, Malaysia. Six species of parasites were recovered:Dactylogyrussp.,Rhabdochona penengensisFurtado, 1965;Proteocephalussp.,Bothriocephalus acheilognathiYamaguti, 1934,Pallisentis gaboesMacCallum, 1918 andLamproglena minulaCapart, 1943. The prevalence and mean density of two ectoparasites (Dactylogyrussp. andL. minuta) and an endoparasite(B. acheilognathi)were examined in relation to season and host size. Fish were found to be free of these parasites in many months of the year. Prevalence and mean density ofDactylogyrussp. andL. minutawere found to be highest during the early part of wet season, whereas those ofB. acheilognathiwere found to be highest in the later part of wet season. Prevalence ofL. minutaincreased with increasing size offish, but mean density was least in the largest fish. Both prevalence and mean density ofB. acheilognathiwere highest in smaller fish, whereas that ofDactylogyrus sp.showed little variation in the three size–gro

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1986.tb05136.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Some of the consequences of varying flows on the downstream migration of salmon fry were investigated in five replicate streams adjacent to the lower Waitaki River, New Zealand. Fluctuating discharge appeared to increase the number of fry moving downstream, provided that mean water velocities at peak flows exceeded 25 cms−1’and that some fry were migrating out of the streams anyway. Salmonids appear to have a lengthier flow–sensitive period than has been proposed in the literature. Research is required to determine whether recently emerged fry that leave parental spawning streams in New Zealand disperse immediately to the ocean or develop and grow for extended periods en route. It may sometimes be feasible and worthwhile to minimize stream flow variations to encourage fry to remain longer in fresh

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1986.tb05137.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

The ultrastructure of endothelial cells and rodlet cells in the bulbus arteriosus of specimens representing six genera of Cichlidae is described. The former are very closely packed by membrane–bound and mainly electron–dense inclusion bodies (0.3–0.7μm).InApistogramma ramireziI observed numerous subendothelial rodlet cells throughout the entire length of the bulbus arteriosus. These cells penetrate the endothelium and connect to the latter by desmosomes and tight junctions. The luminal part of the cell contains numerous vesicles and tubules (width 50–100 nm), whereas the basal part is occupied by a number of membrane–bound, club–like inclusions (length ≤ 5 μm). Between these two layers there occurs a layer of small, elongated mitochondria. Peripherally, these cells consist of a filamentous wall, except in the apical area.The endothelial and rodlet cell inclusion bodies do not react with phosphotungstic acid (pH 1) or Sudan black B stain. The endothelial cells react strongly with periodic acid–Schiff (PAS) stain, whereas the rodlet cells are only moderately coloured by this stain.The present results are discussed and compared with those reported previously for endothelial/ endocardial cells and rodlet c

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1986.tb05138.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Growth energy build‐up and partitioning by immature bluegill sunfish were studied over the summer months from May to September 1984. Fish sampled in May showed low condition and low lipid reserves. Condition was restored to summer levels within the following month. Fat reserves were built up from 7% to 14% of body weight over the entire summer. Most (80%) of the annual length increase occurred from 1 June to 15 August. Over the winter period (October‐April) condition dropped and lipids were depleted. Calculations showed that energy liberated through lipid depletion over this period could supply the energy requirements of inactive wintering fish. It is concluded that the sequencing of growth energy diversion into changes in body length, condition, and lipid build‐up enhances mid‐summer growth and overwinter s

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1986.tb05139.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Electrocardiographic (ECG) abnormalities and arrhythmias have been observed in hyperammonemic patients and in animals injected with ammonium salts. Ammonium is excreted directly into the environment by fish, and it is a potent fish toxin, but the effects of ammonium on the cardiovascular system of fish are unknown. This study investigated the cardiotoxic effects of ammonium on isolated perfused fish hearts. These were compared with ammonium‐induced cardiac electrophysiological abnormalities observed in humans and other experimental animals. Isolated perfused fish hearts exhibit ammonium‐induced cardiac abnormalities similar to the ammonium‐induced abnormalities seen in the hearts of higher vertebrates. Therefore, we conclude that the myocardium of ammonotelic species does not possess a specialized ammonium detoxification mechanism, and that ammonium is cardiotoxic to salmonid

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1986.tb05140.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

A naturally masculinized female of the Clear Creek gambusia,Gambusia heterochirHubbs, was collected from the headspring of Clear Creek, Menard County, Texas. The fish had 11 well‐developed, late stage embryos. It also possessed an incompletely developed gonopodium and a pair of male‐like, pectoral fins. This discovery constitutes the first report of natural masculinization within the genusGambu

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1986.tb05141.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Uptake, time‐course dependent distribution and elimination of cadmium after intraovarian loading with 0.5 mg Cd kg−1body weight was investigated in the pregnantZoarces viviparus(L), to elucidate the dynamics in the maternal‐foetal exchange of cadmium. After 7.5 h 95% of the injected cadmium was eliminated from the ovarian fluid, and half‐life was calculated as T1/2= 100 (S.D. 48) min. It took 48 h to eliminate 95% from the serum, where the half‐life of cadmium was T1/2= 11 (S.D. 3) h. The concentration of cadmium in the embryos increased during the first 5 h postinjection. However, a decrease was observed during the latter part of the experimental period. The liver and kidney of the mother fish showed a continuous accumulation during the 72‐h period of investigation. The negative linear correlation between elimination from the serum and the uptake in the liver, was calculated to

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1986.tb05142.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Effects of oral administration of lead and cadmium on structure and function of trout intestine were investigated inSalmo gairdneri.Fish were fed either cadmium (5 mg kg*1fish per day) or lead (10 mg kg−1fish p er day) and sacrificed after a 15 or 30 day treatment.Levels of cadmium and lead in kidney, liver and spleen were significantly increased by the 15th day of treatment.Following both cadmium and lead treatment, morphological observations showed an increased mucous cell activity, a disruption of intestinal brush border and an increased renewal rate of absorptive cells.Influx (Jms), outflux(Jsm)of chlorine and sodium ion and net fluxes were measured on perfused intestinal segments and ouabain‐sensitive sodium, potassium‐ATPase (Na, K‐ATPase) activity was determined on intestinal scrapings. Cadmium did not alter either sodium chlorine transepithelial fluxes or sodium, potassium‐ATPase activity, but lead did. In the middle intestine, lead modified significantly transepithelial sodium and chlorine fluxes (JmsNa: 3.21 ± 0.34 to 1.79 ± 0.29 and JmsCl: 3.32 ± 0.34 to 1.86 ± 0.22μmol h−1cm−2,n = 6)after 30‐day diet.Jnetremain unchanged and Na, K‐ATPase activity decreased. In the posterior intestine, lead altered onlyJmsNa (1.95 ± 0.31 to 0.37 ± 0.09μmol h−1cm−2) andJmsCl. ConsequentlyJneswere also decreased.So, although both cadmium and lead induce morphological disorders in the middle and in the posterior intestine of the trout, they have different effects on the

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1986.tb05143.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Carnitine treatment has an appreciable effect on the hatchery‐reared sea bass,Dicentrarchus labrax, fry.The administration of the laevorotatory isomer (1‐carnitine) which is engaged in the transport of the acyl and acetyl groups through the mitochondrial membrane, stimulating lipid metabolism, increases the growth rate and the protein content of the treated fry.The dextrorotatory isomer (d‐carnitine), which is an antagonist of the 1‐carnitine, has an opposite effect on the growth and metabolism of the trea

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1986.tb05144.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY