Triploid brown trout, Salmo trutta, develop functional gonads with age and are able to interbreed with diploid counterparts.

The study investigated if gonad maturation in triploid brown trout, Salmo trutta, was entirely suppressed or only delayed, and if triploids could interbreed with diploid counterparts. Ten percent of the total number of 3-year-old triploid S. trutta, 15% of 4-year-old fish, and 17% of 5-year-old fish produced semen.

Morphometric and Enzymatic Changes in Gills of Rainbow Trout after Exposure to Elevated Temperature-Indications for Gill Remodeling.

Seven-month-old rainbow trout acclimated to 9 °C were used. The fish were gradually adapted to a water temperature of 20 °C over a period of seven days and then exposed to this temperature for 32 days. Changes in gill morphometry and histology and in enzyme activities in comparison to fish kept at 9 °C were investigated.

Hematological adaptations in diploid and triploid Salvelinus fontinalis and diploid Oncorhynchus mykiss (Salmonidae, Teleostei) in response to long-term exposure to elevated temperature.

Hematology is a simple but reliable method to determine the influence of environmental stressors on the physiology and performance of teleost fish. Understanding the detailed impacts of elevated temperature on the hematology of fish can help us to evaluate fish responses to climate change. Therefore, cellular and biochemical changes in peripheral blood were investigated in diploid (2n) and triploid (3n) brook trout and in 2n rainbow trout exposed to 20 °C for 32 days in comparison to fish acclimated to 9 °C.

Seasonal differences in thermal stress susceptibility of diploid and triploid brook trout, Salvelinus fontinalis (Teleostei, Pisces).

Many physiological processes of teleost fish show periodicity due to intrinsic rhythms. It may be hypothesized that also susceptibility to thermal stress differs seasonally. To shed more light on this problem the following experiment was conducted.

Differences in immune components of blood, spleen and head kidney between diploid and auto- and allotriploid Salmonidae.

Immune components were investigated in peripheral blood and in spleen and head kidney of autotriploid Salmo trutta f. lacustris, Salvelinus fontinalis, and Salvelinus umbla, and of allotriploid hybrids of S. trutta f.

Pressure shock triploidization of Salmo trutta f. lacustris and Salvelinus umbla eggs and its impact on fish development.

The study tested the efficiency of hydrostatic pressure triploidization methods for Salmo trutta f. lacustris and Salvelinus umbla and investigated the effects on survival rate, skeletal malformation, and on morphometrics and cellular composition of gills, spleen, liver, kidney, intestine, and blood. In Salmo trutta f.

Possibilities to control Ichthyophthirius multifiliis infestation with medicated feed in rainbow trout (Oncorhynchus mykiss) and chub (Leuciscus cephalus).

In the present study, the treatment of ichthyophthiriasis with medicated feed was investigated in rainbow trout, Oncorhynchus mykiss, and chub, Leuciscus cephalus. The anti-parasitics toltrazuril and imidocarb; the antibiotics doxycycline, erythromycin and sulphadiazine and the anti-inflammatory acetylsalicylic acid were tested. In vitro experiment revealed that all tested anti-parasitics and antibiotics were effective in killing the isolated trophonts and theronts.

The effect of K(+), Ca (2+), and Mg (2+) on sperm motility in the perch, Perca fluviatilis.

This study investigated the effect of 0.25-5 mM K(+), Ca(2+), and Mg(2+) on sperm motility in the perch, Perca fluviatilis. In 75 mM NaCl, the used motility-activating solution, motility rate, and swimming velocity decreased within the first 4 min after activation, and the rate of locally motile sperm increased.

Effect of Temperature on gametogenesis and gamete quality in brown trout, Salmo trutta.

During the prespawning and spawning season experimental groups of +2 year male and female brown trout, Salmo trutta, were kept under natural photoperiod and at three temperature regimes, a naturally fluctuating one with an average temperature of 7.4 ± 4.6°C as typical for alpine and prealpine river systems (T1), a naturally fluctuating one elevated for circa 5°C to 12.

The effect of antioxidants on the quality of cryopreserved semen in two salmonid fish, the brook trout (Salvelinus fontinalis) and the rainbow trout (Oncorhynchus mykiss).

Until now the supplementation of cryopreservation extenders with antioxidants has not been examined in teleost fish. Therefore, the present study investigated whether addition of antioxidants (catalase, superoxide dismutase, peroxidase, reduced glutathione, reduced methione, mixtures of reduced and oxidized glutathione or methionine) to the cryopreservation extenders could increase the quality of frozen-thawed semen of brook trout, Salvelinus fontinalis, and rainbow trout, Oncorhynchus mykiss. In brook trout and rainbow trout semen post-thaw fertility and motility were evaluated and in brook trout additionally the membrane integrity, DNA integrity, and sperm lipid peroxidation were evaluated.

The effect of water temperature on gamete maturation and gamete quality in the European grayling (Thymalus thymallus) based on experimental data and on data from wild populations.

To investigate the effect of water temperature on gamete maturation and gamete quality, European grayling (Thymalus thymallus) were held under different temperature regimes prior to spawning. Maturation of males and females and their gamete quality depended strongly on temperature regime. The highest percentages of maturing fish and highest gamete quality were obtained under a creek water temperature regime with natural seasonal fluctuations.

A comparative study on the composition and importance of free amino acids in semen of gilthead sea bream, Sparus aurata, and perch, Perca fluviatilis.

A comparative study was conducted on the free amino acid composition of gilthead sea bream, Sparus aurata, and perch, Perca fluviatilis. Also the effect of 21 free amino acids on sperm motility was investigated. Spermatozoa were incubated in species-specific motility-inhibiting saline solution containing the different amino acids for 48 h.

Motility and cryopreservation of spermatozoa of European common frog, Rana temporaria.

Motility and cryopreservation of testicular sperm of European common frog, Rana temporaria were investigated. Collected testicular spermatozoa were immotile in solutions of high osmolalities: 300 mmol/l sucrose and motility inhibiting saline solution-MIS. Full sperm motility could be activated in distilled water or in a solution of 50 mmol/l NaCl, = 90 mosmol/kg, with 75-90% motility and 14-16 microm s(-1) swimming velocity.

Composition and metabolism of carbohydrates and lipids in Sparus aurata semen and its relation to viability expressed as sperm motility when activated.

The present study investigated aspects of lipid and carbohydrate metabolism in Sparus aurata semen and tested the effect of lipids, carbohydrates and related metabolites on sperm viability using in vitro incubation experiments. Sparus aurata semen contained enzyme systems to metabolize sugars and lipids. Also key enzymes of the tricarboxylic acid cycle and enzymes involved in ATP metabolism were detected.

Antioxidant systems of brown trout (Salmo trutta f. fario) semen.

The present study characterizes the antioxidant systems of brown trout, Salmo trutta, semen as supplementation of semen dilution media with antioxidants can be beneficial to improve techniques for semen storage and cryopreservation. Antioxidants and oxidant defensive enzymes of spermatozoa and seminal plasma were analyzed. To determine whether antioxidants and oxidant defensive enzymes have an effect on sperm functionality, in vitro experiments were performed.

A fine structural review on the spermatozoa of Cyprinidae with attention to their phylogenetic implications.

The fine structural organization and dimensions of spermatozoa from species of 4 subfamilies of the Cyprinidae (Barbus barbus, Carassius carassius, Cyprinus carpio carpio, Cyprinus carpio haematopterus, Abramis brama, Alburnoides bipunctatus, Alburnus alburnus, Chalcalburnus chalcoides mento, Chondrostoma nasus, Hypophthalmichthys molitrix, Leuciscus cephalus, Phoxinus phoxinus, Rutilus rutilus, Rutilus meidingerii, Scardinius erythrophthalmus, Vimba vimba and Ctenopharyngodon idella) are compared with each other as well as with results from other studies. Based on these descriptions it is investigated whether sperm structure reveals correlations with the existing systematics and if it could be a useful taxonomical parameter. The scatter plots based on the discriminate analysis and the neighbour-joining trees based on a Mahalanobis distance matrix reveal that sperm organization is related with systematics in many aspects.

Evaluation of quantitative importance of egg lipids and fatty acids during embryos and larvae development in marine pelagophil teleosts: with an emphasis on Dentex dentex.

Quantitative compositin of Dentex dentex eggs lipid classes (LCs) and fatty acid (FA)s were measured and correlated to embryo and larva viability parameters (egg buoyancy, floating rate (FR), hatching rate, HR and survival rate, SR, at 0-5 days post hatch, dph) through 43 formulated models (38 using FAs, as independent variable, [R(2) = 0.641-0.859] and 5 using LC [R(2) = 0.

Quantitative composition of vitellogenin-derived yolk proteins and their effects on viability of embryos and larvae of common dentex (Dentex dentex), a marine pelagophil teleost.

To evaluate the importance of the quantitative composition of vitellogenin (Vtg)-derived egg yolk proteins during initial events of Dentex dentex life, viable eggs were obtained from captive broodstocks. Viability parameters (Vps; egg buoyancy (FR), hatching rate (HR), and larval survival rate (SR) at 0, 3, and 5 days posthatch (dph)) were determined for 70 egg batches. Vtg-derived yolk proteins were purified from the eggs using cation-exchange chromatography, separated and detected by SDS-PAGE, identified and characterized using mass spectrometry, quantified using image densitometry, and finally correlated to VPs.

The sensitivity and reproducibility of the zebrafish (Danio rerio) embryo test for the screening of waste water quality and for testing the toxicity of chemicals.

The sensitivity of the zebrafish embryo test, a test proposed for routine waste water control, was compared with the acute fish toxicity test, in the determination of six types of waste water and ten different chemicals. The waste water was sampled from the following industrial processes: paper and cardboard production, hide tanning, metal galvanisation, carcass treatment and utilisation, and sewage treatment. The chemicals tested were: dimethylacetamide, dimethylsulphoxide, cadmium chloride, cyclohexane, hydroquinone, mercuric chloride, nickel chloride, nonylphenol, resmethrin and sodium nitrite.

Treatment of ichthyophthiriasis in rainbow trout and common carp with common and alternative therapeutics.

The goal of this laboratory study was to provide better knowledge about the treatment of ichthyophthiriasis (causative agent: Ichthyophthirius multifiliis, a ciliate bacteria) in rainbow trout Oncorhynchus mykiss and common carp Cyprinus carpio. The following questions were investigated: (1) the effectiveness of different chemicals (formalin, sodium chloride, hydrogen peroxide, Perotan, Virkon, Aquahumin, Baycox, and Ivomec) and at different concentrations and durations of application, (2) the number of treatments and the time intervals between treatments that were necessary to remove the parasite, and (3) how treatment effectiveness differed between the two species. The most effective treatment was a 37% stock solution of formalin at 110 microL/L of bath water for 1 h in rainbow trout and for 2 h in common carp.

Effect of bisphenol A on maturation and quality of semen and eggs in the brown trout, Salmo trutta f. fario.

In the present study male and female brown trout (Salmo trutta f. fario) were exposed to environmentally relevant concentrations of bisphenol A (1.75, 2.

Carbohydrate metabolism of eggs of the whitefish, Coregonus spp. during embryogenesis and its relationship with egg quality.

The present study investigated the changes in carbohydrate metabolism of eggs of the whitefish, Coregonus spp. during embryogenesis (unfertilized eggs to embryos in the eyed stage). Occurrence of glycolysis was proved by activities of phosphofructokinase (PFK-1) and pyruvate kinase and by decreasing levels of hexose, pentose phosphate pathway by transaldolase (non-oxidative path) and glucose-6-phosphate dehydrogenase activities (oxidative path) and by increasing ribose levels, fructose synthesis (polyol pathway) by sorbitol dehydrogenase activities, gluconeogenesis by activities of glucose-6-phosphatase.

The effect of 4-nonylphenol on semen quality, viability of gametes, fertilization success, and embryo and larvae survival in rainbow trout (Oncorhynchus mykiss).

The present study investigated in vivo and in vitro effects of environmental relevant concentrations of 4-nonylphenol (100-750 ng l(-1)) on the reproduction of rainbow trout (Oncorhynchus mykiss). To determine the effect of 4-nonylphenol on semen quality rainbow trout were exposed to three concentrations of 4-nonylphenol in a flow-through system during the spawning period (60 days). At an estimated 4-nonylphenol concentration of 750 ng l(-1) semen production was completely inhibited, at 280 and 130 ng l(-1) the semen production was significantly reduced in comparison to the control.

Seminal vesicle secretion of African catfish, its composition, its behaviour in water and saline solutions and its influence on gamete fertilizability.

The seminal vesicle secretion (SVS) of the African catfish, Clarias gariepinus, was investigated by analytical and experimental methods. SVS consists mainly of proteins and glycoproteins which are responsible for its viscous and sticky nature. The secretion contains also high activities of acid phosphatase, alkaline phosphatase, and proteases.

Seminal plasma proteins prolong the viability of rainbow trout (Oncorynchus mykiss) spermatozoa.

Rainbow trout (Oncorhynchus mykiss) spermatozoa were incubated in artificial sperm motility inhibiting saline solution (SMIS), in SMIS containing seminal plasma proteins or in pure seminal plasma. In SMIS containing the total seminal plasma protein fraction or the <50 kDa protein fraction or in pure seminal plasma, significantly higher motility rates and swimming velocities could be activated than in SMIS without seminal plasma proteins and in SMIS containing the >50 kDa protein fraction. These preliminary results indicated that seminal plasma proteins have physiological functions in prolongation and stabilization of sperm viability when using sperm motility as viability index.