SPERMIATION OF COMMON TENCH (TINCA-TINCA L) STIMULATED WITH INJECTIONOR IMPLANTATION OF GNRH ANALOGS AND INJECTION OF CARP PITUITARY EXTRACT

Spermiation was stimulated in the common tench, Tinca tinca L., by inj ection of carp pituitary extract (CPE; 0.5 mg.kg(-1) body weight), car p homogenized pituitary (1 mg.kg(-1) body weight), [D-Arg(6),Pro(9)-NH Et] salmon GnRH (20 mu g.kg(-1) body weight) and [D-Ala(6),Pro-NHEt] m ammalian GnRH slow-releasing implants at a dose of 25 mu g per male (a verage, 652 g of body weight), The sperm was collected daily for 5 day s post-stimulation and diluted with immobilizing solution (180 mM NaCl , 20 mM Tris, pH 7). Sperm density, expressed as billions per kg of bo dy weight, was 47.31 for CPE, 49.42 for carp homogenized pituitary, 51 .84 for (D-Arg(6),Pro(9)-NHEt] salmon GnRH, 28.93 for GnRH analogue im plant and 13.73 for the control group treated with Ringer solution. Th e total number of spermatozoa obtained by stimulation with [D-Arg(6),P ro(9)-NHEt] salmon GnRH was significantly higher (P < 0.05) than for t he carp-hypophysis-treated groups. The best spermiation with the GnRH analogue implantant group was at 4 days after implantation (P < 0.001) .