ARTIFICIAL SPAWNING OF EUROPEAN CATFISH (Silurus glanis L.) USING SMALL DOSES OF CARP PITUITARY GLANDS

Abstract

In 1997 and 1998 in the “Ribnjak 1905”•d. d. Našice hatchery artificial spawing of European catfish (Silurus glanis L.) was researched under productive conditions using small doses of carp pituitary (CP). Befiwe dosing the carp pituitary glands female catfish were marked, weighed out, grouped according-to their maturity and devided in 5 categories based on grade of their maturity (MC). We used our own criteria. In the controlled group (n=21) female catfish received a single CP shot dosed at 4.5 mg. kg -1 of the body weight (b. w.), while in the experimental group (n=62) female fish were treated with single low dosed CP on three levels. It was found out that the minimal CP dosage for the artificial spawning on the 3rd MG is 2.04+-0.15, on the 4th MG 1.59+-0.16 and on the 5th MG 1.25+-0.10 mg. kg-1 of the b. m. Simultaneously, the efficiency of spawning compared to the controlled group was not reduced because it ranged between 92-100% (p<0.0.5), while relative fertility on the 3rd, 4th and 5th maturity grade totalled 9.9+-2.1, 10.4+-1.6 and 11.5+-1.3%, (p<0.05) adequately. The established minimal CP dosages for spawning of European catfish are two to three times lower than relevant data from the reference literature. It is assumed that they will have positive influence on final harmonic maturing process of the oocytes oocita, and by that on better quality of ovulated eggs.

Keywords

• artificial spawning
• european catfish
• doses of pituitary glands