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The composition of seminal plasma and metabolism of sperm of the cyprinid fishAlburnus alburnus were investigated. Statistically significant correlations were found between motility parameters and seminal fluid osmolality, pH, Na(+), K(+) and protein levels (negative correlations: % immotile spermatozoa-Na(+), K(+); positive correlations: % motile spermatozoa-osmolality, pH, Na(+), K(+), protein; % linear motile spermatozoa-pH protein; swimming velocity of spermatozoa-pH, Na(+), protein). Spermatozoan motility and ATP metabolism and glycolysis were correlated as indicated by measurement of ATPase, pyruvate kinase, adenylate kinase and lactate dehydrogenase activity. The physiological meanings of these correlations and their possible significance for quality control of semen are discussed.

Oocytes and eggs from teleost fishes are always surrounded by an egg envelope of variable dimensions. This envelope (zona radiata) in teleosts normally consists of two layers, a zona radiata interna and a zona radiata externa. The chemical composition of the interna is proteinaceous. Neutral and acid mucopolysaccharides are the main components of the externa. The zona radiata interna is largely responsible for a protective function, whereas the zona radiata externa is used to attach the eggs to the substrate where they are deposited. For the latter it is equipped with variable mechanisms such as special sticky layers (e.g., in Phoxinus pboxinus, Chalcalburnus chalcoides mento, Esox sp., Lota lota and 1-eggs in cichlids), hexagonal patterns (e.g., in many percids and in channichthyids), villi-like protuberances (= attaching-plugs; in many cyprinids), attaching-filaments (e.g., in gobies and blennies, p-eggs in cichlids, piranhas and clariids), a jelly layer (Perca fluviatilis) or a muco-follicle epithelium (Silunis glanis). This enables not only an attachment to the substrate but the eggs also can be placed in clusters and may be protected by the fish species which guard their egg deposits. In water bodies which have little or greatly reduced available oxygen, the eggs may be attached to plant tips and thus help to ensure adequate supplies of oxygen.

Summary ― The ovarian fluid of rainbow trout (Oncorhynchus mykiss), charr (Salvelinus alpinus), lake trout (Salmo trutta f lacustris) and Danube salmon (Hucho hucho) was analyzed for its inorganic and organic composition. The qualitative composition of the ovarian fluid of the investigated species was similar, but significant quantitative differences were found. The following components were determined: sodium 106.6-142.2 mmol/I, potassium 1.7-2.7 mmol/I, calcium 0.45-0.61 mmola, osmolality 256.4-291.6 mosmol/kg, pH 8.4-8.8, glucose 1 698-4 195 wmol/I, fructose 17-399 pmol/I, lactate 34-227 gmol/l, cholesterol 650-1 230 pmolfl, phosphatidylcholine 0.25-3.0 pmoUl, lysophosphatidylcholine 10-100 Jl mol/l, choline 0-1.1 pmol/I, protein 95.0-278.4 mg/100 ml. Arginine, cystine, glycine, histidine, lysine, proline, serine, tyrosine and valine were the free amino acids occurring in concentrations of more than 10 0 pmolfl. Activities of alkaline phosphatase (200-6 000 pmol substrate/I/h), lactate dehydrogenase (9-690 gmol substrate/I/h), p-D -giucuronidase (70-410 pmol substrate/I/h), proteases pmolfl, fructose 17-399 pmolfl, lactate 34-227 pmolfl, cholesterol 650-1230 pmolfl, phosphatidylcholine 0,25-3,0 pmolll, lysophosphatidylcholine 10-100 pmol/1, choline 0-1,1 1 gmoili, protéines 95,4-278,4 mgl100 mL Arginine, cystine, glycine, histidine, lysine, proline, sérine, tyrosine et valine étaient les acides aminés libres dont la concentration excédait 10 pmolll. Des activités phosphatase alcaline (200-6000 pmol substratlllh), lactate déhydrogénase (9-690 gmoi substratlilh), /3-o-glucuronidase (70-410 0 pmol substrat/I/h), protéases (140-215 gmoilllh avec le collagène, 25-90 pmollllh avec la gélatine) et phosphatase acide (100-130 pmol subsiratlllh) étaient détectables, mais la glucose-6-phosphate déhydrogénase et l'a-glucosidase étaient absentes.

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The influence of permeating and of non-permeating cryoprotectants on motility, eosin permeability (sperm cells viability test) and leaking lactate dehydrogenase activity of spermatozoa of the rainbow trout (Oncorhynchus mykks) was investigated. Correlations between sperm motility rate, percentage of eosinimpermeable (viable) cells and LDH activities established the three parameters as indicators for damages to rainbow trout spermatozoa. High sperm motility rates, velocities, and numbers of linear swimming sperm cells, high numbers of eosinimpermeable spermatozoa and a low extracellular LDH activity were evaluated as positive quality characteristics of semen. With a buffered physiological saline solution as basic extender we found a mixture of 0.67 mol/L (5 %) dimethylsulfoxide (DMSO) and 0.13 mol/L (1 %) glycerol to be the most effective cryoprotectant, followed by DMSO (0.67 mol/L [5 %,I-1.85 mol/L [15%]) and glycerol (0.65 mol/L [5%]-1.78 mol/L [15 %])andpropanediol(l.24mol/L[10%]-1.78 mol/L[15 "/o]). Addition of hen egg yolk (7 %, 20 Yo) and of 15 mmol/L (0.5 %)sucrose significantly increased the semen quality in comparison to the same extender without these additives. Bovine serum albumin (1.5 YO, 3 YO) had no influence on the investigated semen parameters. lntroductionCryopreservation of fish semen is still a field of intensive research (for review see Jamieson 1991). Numerous studies have been performed especially in salmonid fishes (e.Piironen 1993). However, the techniques vary greatly (e.g. extender composition and cryoprotectants, freezing and thawing conditions, fertilization technique) (Scott and Baynes 1980;Stoss 1983;Billard 1992) and no generally accepted concept has yet been found. Evaluation of physiological and biochemical semen parameters could give more information about alterations and damages of spermatozoa during cryopreservation (Malejac et al. 1990;Billard 1992), but most studies are based on fertilization assays only.Therefore we investigated the influence of some commonly used cryoprotectants on motility parameters (computer-assisted cell motion analysis), eosin permeability (sperm cells viability test) and enzyme (lactate dehydrogenase) activities which were released from sperm cells of the rainbow trout (Oncorhynchus mykiss). Since no good, theoretical model is available for the freezing of salmonid semen, a conventional buffered physiological saline solution and freezing in straws are used as basis. Materials and methods Collection of gametesMature male rainbow trout (Oncorhynchus mykiss, winter strain, age 2-4 years) were obtained from the Kreuzstein (Salzburg) fish farm. Fishes used for the experiments were in a running stage and in the middle of the spawning season. The urinary bladder was cleared by gentle abdominal pressure and thereafter the semen was collected by stripping, giving 5-8 ml per male. Sperm density was 8-10 x lo9 spermatozoa x ml-' (determined in a Burker Turk counting chamber, 1000-fold dilution).Samples contaminated with blood, urine and faeces were discarded. T...

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