Some characteristics of mitochondrial monoamine oxidase activity in eggs of carp (Cyprinus carpio) and rainbow trout (Salmo gairdneri)

1. Monoamine oxidase (MAO) activity towards tryptamine, 5-hydroxytryptamine (5-HT) and phenylethylamine (PEA) has been measured in mitochondria isolated from carp and trout eggs. 2. In carp eggs all the tested substrates are metabolized and the highest affinity is found with tryptamine. In trout eggs a consistent level of MAO activity is obtained using tryptamine. 3. The inhibition dose-response curves of clorgyline and deprenyl indicate that both in carp and trout eggs there is only one form of mitochondrial MAO, distinct from MAO A and B which have been described in vertebrate tissues. 4. Both in carp and trout egg mitochondria a semicarbazide-sensitive amine oxidase is not involved in the deamination of the used substrates. 5. MAO found in carp and trout eggs might be involved in metabolism of some neurotransmitter monoamines during early developmental stages.     

A comparative study of glycolysis in red and white muscles of the trout (Salmo gairdneri) and mirror carp (Cyprinus carpio)

The activities of some glycolytic and associated enzymes have been determined in the muscles of trout and carp to investigate the possibility that the discrepancies previously reported between lactate accumulation and anoxic tolerance in these two fish result from underlying differences in glycolytic potential. Steady state concentrations of certain glycolytic intermediates were also determined in freeze-clamped muscles from tankrested fish. The activities of hexokinase, phosphorylase and phosphofructokinase were approximately 2–3 times lower in carp than trout white muscles. Pyruvate kinase and lactate dehydrogenase activities were 5 times lower in carp white muscle. The lower, broader pH optima of lactate dehydrogenase and pyruvate kinase from carp compared to trout muscles is thought to be correlated with the greater anoxic tolerance of the carp. Glycolytic enzyme profiles were markedly different between the red and white muscles of the rainbow trout but broadly similar, with the exception of hexokinase activity, for the corresponding muscles of the carp. The results are discussed in relation to what is known about anaerobiosis in these two species and the comparative physiology of red and white muscles in fish.     

Haematological assessment of the effects of the anaesthetic MS 222 in natural and neutralized form in three freshwater fish species: intraspecies differences

The effects of different concentrations of natural MS 222 and neutralized MS 222 were studied on the haematology of Cyprinus carpio, Sarotherodon mossambicus and Salmo gairdneri . As judged from the results, MS 222, which is acidic in nature, produced haemo-concentration effects in all species studied, being least in the trout followed by carp and Sarotherodon mossambicus . These differences are ascribed to acid-base regulatory functions and metabolic activities of the fish species investigated. The use of neutralized MS 222 improved the haematological profiles markedly and resulted in stabilization of acid-base parameters and red blood cells sizes and numbers. Haemoconcentration effects, however, still persisted. Trout were found to be more susceptible to the stress of MS 222 anaesthesia than carp and Sarotherodon mossambicus .     

Biochemical polymorphisms in South African freshwater fish. Isoenzyme patterns in fish of the families Cyprinidae and Salmonidae

Isoenzyme patterns were studied in local populations of the carp ( Cyprinus carpio ) and the bream ( Sarotherodon mossambicus ) of the Cyprinid family. and in the trout ( Sabno giardneri ) of the family Salmonidae. Homogenates of heart muscle extracts were used in the identification of PGI. NADP-IDH. PGM and 6-PGD.
Polymorphisms found and gene frequencies obtained are discussed separately for each enzyme and species or population.
In the bream, variation was found only at the PGI locus. In the carp only the PGM locus was polymorphic whereas both PGM and IDH showed variation in the trout. The variation at the PGM locus in the trout cannot support the three locus model suggested elsewhere and clearly indicates a single locus for the mo-nomeric enzyme.
The large variety of NADP-IDH types in trout not only illucidates the complexity of this locus but confirms a disomic mode of inheritance. Genetic differences in the trout populations could be related to possible advantages for management purposes.     

Biochemical polymorphisms in South African freshwater fish. Isoenzyme patterns in fish of the families Cyprinidae and Salmonidae

Isoenzyme patterns were studied in local populations of the carp (Cyprinus carpio) and the bream (Sarotherodon mossambicus) of the Cyprinid family, and in the trout (Salmo giardneri) of the family Salmonidae. Homogenates of heart muscle extracts were used in the identification of PGI, NADP-IDH, PGM and 6-PGD. Polymorphisms found and gene frequencies obtained are discussed separately for each enzyme and species or population. In the bream, variation was found only at the PGI locus. In the carp only the PGM locus was polymorphic whereas both PGM and IDH showed variation in the trout. The variation at the PGM locus in the trout cannot support the three locus model suggested elsewhere and clearly indicates a single locus for the monomeric enzyme. The large variety of NADP-IDH types in trout not only illucidates the complexity of this locus but confirms a disomic mode of inheritance. Genetic differences in the trout populations could be related to possible advantages for management purposes.     

Flow cytometric analysis of the neutrophil respiratory burst of ayu,Plecoglossus altivelis: comparison with other fresh water fish

Neutrophils of vertebrates undergo respiratory burst activity (RBA) as a defense mechanism against bacterial infections. We report here that ayu (Plecoglossus altivelis) have unusually high RBAs even when they are in a healthy condition. Kidney and blood leukocytes were obtained from ayu, rainbow trout (Oncorhynchus mykiss), carp (Cyprinus carpio), eel (Anguilla japonica), and pond smelt (Hypomesus nipponensis). Neutrophil RBA was measured by flow cytometry using dihydrorhodamine after stimulation with phorbol myristate acetate. The amount of RBA of neutrophils from both blood and kidney was significantly higher in ayu than in the other species (e.g. the fluorescence intensity of ayu blood neutrophils was about 3-7 times higher than that from trout and carp, and that of ayu kidney neutrophils was 2-19 times higher than that of rainbow trout, carp, eel, and pond smelt). This unique character of ayu neutrophils was invariable even at different ages, locations, and sex-maturation stages.     

Depletion of high energy phosphates implicates post-exercise mortality in carp and trout; an in vivo 31P-NMR study.

As in vivo 31P-Nuclear Magnetic Resonance spectroscopy is currently the state of the art method to measure continuously intracellular pH (pH(i)) and energy status of muscle tissue, we used this method to study the recovery from exhaustive exercise. The biochemical changes during recovery are not well understood and it was suggested that post-exercise mortality could be caused by low pH(i); other studies however indicate that energy depletion might be more important. To analyse the mechanism of post-exercise recovery pH(i), ATP, P(i), and PCr must be measured at the same time, which is possible using in vivo 31P-NMR. Common carp and rainbow trout of about 100 g were exercised to exhaustion in a swim tunnel. After swimming 10 h at 1.5 body lengths (BL)/s (aerobic control), 50% of the fish were forced to swim at 6 BL/s until exhaustion. Recovery of energy rich phosphates was found to be faster in carp (1.2-1.9 h) than in trout (1.5-2.3 h). The same applied for the recovery from acidosis, which took 1.75 h in carp and 5.75 h in trout. In parallel experiments the energy phosphates and lactate levels were measured in liver, red muscle, and white muscle. Exhaustion caused a significant drop in the energy status of red and white muscle tissue of trout and carp (corroborates NMR data), while no change at all was observed in liver tissue. The lactate levels were increased in the muscle but not in liver and blood. While all experimental animals looked healthy after exhaustion, 40-50% of the carp as well as trout died during the recovery phase. The energy status of those individuals measured by 31P-NMR was much lower than that of the survivors, while in contrast there was no difference in pH(i). Thus, it appears that not acidosis but depletion of high energy phosphates disabled muscle function and therefore may have been the cause of death of the non-survivors.     

Depletion of high energy phosphates implicates post-exercise mortality in carp and trout; an in vivo 31P-NMR study

As in vivo 31P-Nuclear Magnetic Resonance spectroscopy is currently the state of the art method to measure continuously intracellular pH (pH(i)) and energy status of muscle tissue, we used this method to study the recovery from exhaustive exercise. The biochemical changes during recovery are not well understood and it was suggested that post-exercise mortality could be caused by low pH(i); other studies however indicate that energy depletion might be more important. To analyse the mechanism of post-exercise recovery pH(i), ATP, P(i), and PCr must be measured at the same time, which is possible using in vivo 31P-NMR. Common carp and rainbow trout of about 100 g were exercised to exhaustion in a swim tunnel. After swimming 10 h at 1.5 body lengths (BL)/s (aerobic control), 50% of the fish were forced to swim at 6 BL/s until exhaustion. Recovery of energy rich phosphates was found to be faster in carp (1.2-1.9 h) than in trout (1.5-2.3 h). The same applied for the recovery from acidosis, which took 1.75 h in carp and 5.75 h in trout. In parallel experiments the energy phosphates and lactate levels were measured in liver, red muscle, and white muscle. Exhaustion caused a significant drop in the energy status of red and white muscle tissue of trout and carp (corroborates NMR data), while no change at all was observed in liver tissue. The lactate levels were increased in the muscle but not in liver and blood. While all experimental animals looked healthy after exhaustion, 40-50% of the carp as well as trout died during the recovery phase. The energy status of those individuals measured by 31P-NMR was much lower than that of the survivors, while in contrast there was no difference in pH(i). Thus, it appears that not acidosis but depletion of high energy phosphates disabled muscle function and therefore may have been the cause of death of the non-survivors.     

In situ management options to improve crucian carp (Carassius carassius,L.) and brown trout (Salmo trutta,L.) population status in Central Europe: A case study from the Czech Republic

The crucian carp (Carassius carassius, L.) and the brown trout (Salmo trutta, L.) are vanishing from freshwater ecosystems of central Europe. To conserve both species, tailor‐made conservation management of habitats and populations of both species was implemented and tested in the Czech Republic (central Europe). This management was adjusted to reflect the ecological needs of both species. This study aimed to describe the results of a tested in situ management and to analyze the population growth of brown trout and crucian carp under ideal conditions. An experiment was performed at 14 small gravel pit lakes. Seven of them were adjusted to fit the crucian carp habitat requirements while the other seven were treated as a control group. The same experiment was done on 14 smaller streams and with brown trout. The occurrence and growth of crucian carp and brown trout were surveyed over 2 years. A significantly faster growth of both crucian carp and brown trout was observed on the adjusted lakes and streams in comparison to the control group ones. Trout and carp prospered on small streams and gravel pit lakes (respectively) that were free of angling, fish stocking, pollution, piscivorous predators, and competition with hybridizing species like Prussian carp (Carassius auratus, L.) or hatchery‐reared brown trout.     

Non-native freshwater fishes in Norway: history, consequences and perspectives

At present, there are 43 self-sustaining fish species in Norwegian fresh waters, 11 (26%) of which are non-native, representing four families (Salmonidae, Cyprinidae, Centrarchidae and Ictaluridae). Human-mediated fish introductions probably began in the 15th century with common carp Cyprinus carpio, but most have occurred between the late 1800s and late 1900s. The number of known established populations varies from one (goldfish Carassius auratus ) to nearly 250 (tench Tinca tinca ). Dispersal risk is also highest with tench, which is being spread by anglers for its appeal as a trophy fish. Intentional introductions to improve amenity angling have been part of fisheries management programmes ( e.g. brook trout Salvelinus fontinalis ), so this appears to be an increasingly common introduction vector despite the prohibition under legislation of introducing any species of non-native fishes. Some introduced species, such as brook trout, have declined in abundance and number of populations as the quality of acidified waters has been restored, being replaced by native brown trout Salmo trutta . Further range expansion by some species ( e.g. common carp, goldfish and pumpkinseed Lepomis gibbosus ) is probably restricted by current climatic conditions.     

Studies on the role of exogenous proteolytic enzymes in digestion processes in fish

Studies were carried out on the proteolytic activity of the fry of common carp, rainbow trout, grass carp, and whitefish, as well as on the activity of digestive organs of adult common carp and rainbow trout. Activity of exogenous enzymes in relation to endogenous ones was assessed on the basis of the proteolytic value of fish food and the activity of digestive organs. It was found that the share of proteolytic enzymes of natural food in the digestion process in fish was high. Beginning from a weight of 50–100 g for common carp and 10 g for rainbow trout, the relation between the daily enzymatic ration and the weight of fish indicates the cooperation of an approximately constant amount of exogenous enzymes.     

Differences in some properties of lactate dehydrogenase from muscles of the carp Cyprinus carpio and trout Salmo gairdneri

Some catalytic and kinetic properties of lactate dehydrogenase (LDH) isolated from trout and carp skeletal muscles were compared. The specific activity of LDH in the carp muscle was lower by about one third than the activity in the trout muscle. Temperature and pH optima for LDH isolated from the carp muscle were higher than those for the trout muscle LDH. Moreover, in direct reaction, the carp muscle LDH had a higher affinity both for pyruvate and for NADH, i.e., it had lower K _M values. Instead, the trout muscle LDH showed the positive kinetic cooperativity (the Hill coefficient > 1) of the substrate and coenzyme binding sites. Thus, the carp LDH seems to function more effectively under anaerobic conditions and at higher temperatures.     

The level and composition of free fatty acids in the plasma of freshwater fish in a post-absorptive condition

The level and fatty acid composition of plasma free fatty acids (FFA) were determined in four important aquaculture teleost species: goldfish (Carassius auratus), common carp (Cyprinus carpio), rainbow trout (Oncorhynchus mykiss) and tilapia (Oreochromis mossambicus). Plasma was obtained from animals after a 3 day fast in order to study the mobilization of fatty acids in a post-absorptive condition. Plasma [FFA] amounted to 0.95 in goldfish, 0.77 in both carp and rainbow trout and 0.30 μmol/ml in tilapia. The fatty acid composition was dominated by mono-unsaturates in goldfish and carp, whereas saturates were the main fatty acids in tilapia. The largest amount of PUFA was observed in rainbow trout (41%) which was considerably higher than in the other species (27–29%). The interspecies differences of plasma FFA levels and patterns are discussed in relation to the site of lipid storage, mobility and other factors.     

The dynamics of the immunologic indices of carp exposed to methylene blue

Several immunological and haematological indices as well as infection of carp with ectoparasites of the Dactylogyrus genus have been studied in fish that have been subjected to methylene blue treatment, to infection with Rhabdovirus carpio and Aeromonas hydrophila in different combinations. A dosage of 0.05 mg/l (exposure lasting for 3 days) over 20 days increases most of the immunological indices. A treatment of the carp with drug (dosage of 100 mg/l) for 4 hours has a stimulating effect on the immune system over a period of 40-60 days. The infection of the carp with virus immediately after the drug treatment (dosage 100 mg/l) gives rise to a disease of a certain part of fish. In connection with this a problem on terms of the methylene blue treatment is discussed taking into account the development of the disease.     

Using invertebrate remains and pigments in the sediment to infer changes in trophic structure after fish introduction in Lake Fogo: a crater lake in the Azores

Fish introduction may have marked effects on the trophic dynamics and ecological state of former fishless lakes, but due to scarcity of historical data this can seldom be documented. We used remains of cladoceran, chironomid and pigment assemblages in the sediment archive to unravel the effect of introduction of carp (Cyprinus carpio), rainbow trout (Oncorhynchus mykiss) and a cyprinid (Chondrostoma oligolepis) in Lake Fogo, the Azores (Portugal). The stratigraphical record showed two major shifts in community assemblage coinciding with the time of introduction of carp (AD ca. 1890) and trout (AD 1941), respectively. Carp introduction was followed by an abrupt and major decline in the abundance of chironomids, a shift in the cladoceran community from a benthic to a more pelagic dominated community, and Daphnia size was significantly reduced. Pigment assemblages also indicated a shift from a benthic to a pelagic dominated ecosystem, as cryptophytes became markedly more abundant at the expense of benthic diatoms. Trout introduction was followed by a return to a more benthic cladoceran and benthic algae (pigments) dominated state, which we attribute to trout predation on carp leading to improved water clarity. A steady increase in the abundance of pigments and cladoceran remains followed, suggesting enhanced productivity, which may be attributed to enhanced atmospheric nitrogen deposition and introduction of C. oligolepis. We conclude that fish introduction has profoundly altered the trophic dynamics and the relative importance of benthic and pelagic production in this species poor and natural fishless lake in the Azores, and likely in most others lakes at the archipelago islands as fish stocking has been a widespread practice.     

Hormonal and ion regulatory response in three freshwater fish species following waterborne copper exposure

We evaluated effects of sublethal copper exposure in 3 different freshwater fish: rainbow trout (Oncorhynchus mykiss), common carp (Cyprinus carpio) and gibel carp (Carassius auratus gibelio). In a first experiment we exposed these fishes to an equally toxic Cu dose, a Cu level 10 times lower than their 96 h LC₅₀ value: 20, 65, and 150 µg/L Cu. In a second series we exposed them to the same Cu concentration (50 µg/L). Na⁺/K⁺-ATPase activity in gill tissue was disturbed differently in rainbow trout then in common and gibel carp. Rainbow trout showed a thorough disruption of plasma ion levels at the beginning of both exposures, whereas common carp and gibel carp displayed effects only after 3 days. Rainbow trout and common carp thyroid hormones experienced adverse effects in the beginning of the exposure. The involvement of prolactin in handling metal stress was reflected in changes of mRNA prolactin receptor concentrations in gill tissue, with an up regulation of this mRNA in rainbow trout and a down regulation in gibel carp, which was more pronounced in the latter. Overall, rainbow trout appeared more sensitive in the beginning of the exposure, however, when it overcame this first challenge, it handled copper exposure in a better manner then common and gibel carp as they showed more long term impacts of Cu exposure.     

Primary-structural and evolutionary analyses of the growth-hormone gene from grass carp (Ctenopharyngodon idellus).

The growth-hormone (GH) gene of grass carp, one of the fastest-growing species of farmed fish, was isolated and the DNA sequenced. Only one GH gene is found in this species. This gene, which is 2.5 kb in length, has five exons and four introns, in common with all of the mammalian and the recently published common-carp GH genes. In the course of vertebrate evolution, the total lengths of the intron and the non-coding region of exon 5 of the GH gene have been shortened by 40-70%, whereas the encoding exons of the gene have been slightly increased. The more closely related species exhibit the closest sequence similarity in their GH genes. For example, the similarity of the exons is 84.1-93.2% between grass carp and common carp (within the same family of Syprinedae), 43.5-82.1% between grass carp and rainbow trout (in different orders of Teleostei) and 45.8-58.6% between grass carp and rat (in different grades of Vertebrata). In addition, similar DNA domains, such as thyroid-hormone-receptor-complex-binding site and cell-type-specific cis elements involved in regulation of expression of rat and human GH genes, have been localized in the corresponding regions of the grass-carp GH gene.     

Studies on the swimming musculature of the rainbow trout.

Some aspects of anaerobic metabolism in the red and white (mosaic) muscles of the rainbow trout have been studied during environmental hypoxia. Evidence has been obtained for the operation of anaerobic pathways other than glycolysis, especially in the superficial red muscle. L-alanine and succinate were observed to accumulate as anaerobic endproducts in this tissue. Anaerobic glycolysis also increased significantly during hypoxia, but only in the white muscle. Glycogen stores were depleted by 70–85 % in both red and white muscle. Glucose increased in concentration in the red but not in the white muscle. In an attempt to understand some of the species differences in the susceptibility of fish to hypoxia the results of the present study have been compared with an earlier study on the carp (Johnston, 1975). The effect of death from hypoxia on the levels of muscle metabolites has also been studied.