B. Urbanyi, A. Horvath, Z. Varga, L. Horvath, I. Magyary, F. Radics-1999
Aquaculture Research, 30 : 145-151
Abstract :
The effect of extenders was studied on the cyopreservation of sperm from African catfish, Clarias gariepinus (Burchell). The following six basic extenders were tested : fructose, glucose, sucrose, NaCl, KCl solutions and the artificial seminal plasma of the African catfish. Each of these extenders was tested both with and without buffer systems (i.e. NaHCO3-CO2 and Tris-HCl) by using 10% dimethylsulphoxide (DMSO) as a cryoprotectant. The two-step freezing was carried out in a programmable freezer by using the following freezing rates : (1) 4 C/min between 3 and -4 C ; (2) and 11 C/min between -4 and -80 C. The best post-thaw motility (25%) was achieved with 333 mmol/L fructose solution and NaHCO3 buffer. The fertilization experiments were carried out with unbuffered fructose and glucose extenders using various amounts of sperm and two fertilization methods : (1) dry and (2) wet. The best fertilization rates were achieved with 75 micro L of sperm and wet fertilization rates with glucose extender, or 100 microL of sperm and dry fertilization in case of fructose - both methods fertilized 96% of all eggs.
(Laboratory of Biotechnology, Department of Applied Animal Genetics and Breeding, Institute of Animal Husbandry, Godollo ; University of Agricultural Sciences, H-2103 Godollo, Pater K. u. l., Hungary, e-mail : urbanyib@nt.ktg.gau.hu)