Composition of the ovarian fluid in 4 salmonid species: Oncorhynchus mykiss, Salmo trutta f lacustris, Salvelinus alpinus and Hucho hucho.

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/l, potassium 1.7-2.7 mmol/l, calcium 0.45-0.61 mmol/l, osmolality 256.4-291.6 mosmol/kg, pH 8.4-8.8, glucose 1,698-4,195 mumol/l, fructose 17-399 mumol/l, lactate 34-227 mumol/l, cholesterol 650-1,230 mumol/l, phosphatidylcholine 0.25-3.0 mumol/l, lysophosphatidylcholine 10-100 mumol/l, choline 0-1.1 mumol/l, 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 mumol/l. Activities of alkaline phosphatase (200-6,000 mumol substrate/l/h), lactate dehydrogenase (9-690 mumol substrate/l/h), beta-D-glucuronidase (70-410 mumol substrate/l/h), proteases (140-215 mumol/l/h with collagen substrate, 25-90 mumol/h/l with gelatine substrate) and acid phosphatase (100-130 mumol substrate/l/h) were measured, but not the glucose-6-phosphate dehydrogenase and alpha-glucosidases activities.