SPERMIATION AND SPERM QUALITY OF EUROPEAN CATFISH (SILURUS-GLANIS L) AFTER IMPLANTATION OF GNRH ANALOGS AND INJECTION OF CARP PITUITARY EXTRACT

Spermiation was stimulated in the European catfish Silurus glanis L. by injection of carp pituitary preparation (5 mg kg-1 of body weight) and mammalian GnRH{(D-Ala6)Gn-RH ProNHEt} implanted at a dose of 75 mug and 150 mug per male, respectively. The total number of spermatozoa collected by daily sampling during 7 days post-stimulation and expressed in millions per kg of body weight was 3.29 with carp pituitaries, 0.872 and 0.780 with 75 mug and 150 mug GnRH analogue implant, respectively, and 0.387 in the control group treated with Ringer solution. In all groups, after sperm stripping there was a spontaneous activation by urine of the spermatozoa motility which was prevented by collection of the sperm in an immobilizing solution (NaCl 200 mM, Tris 30 mM, pH 7). The percentage of motile spermatozoa ranged from 80 to 65% at days 1 to 5, and less than 50% at day 6 and 7. A similar decline of quality was observed with time for mass progressive movement (55 to 65 s on day 1, and 28 to 35 s on day 7) and total duration of displacement (66 to 77 s on day 1, and 45 to 53 on day 7).