en aquaculture aquaculture پژوهشي Orginal research papers <span style="font-size:11pt"><span style="line-height:112%"><span style="tab-stops:21.3pt"><span style="font-family:Calibri,sans-serif"><span lang="TR" new="" roman="" style="border:none windowtext 1.0pt; font-family:" times=""><span style="color:black">This study was aimed to determine the effect of a freezing extender developed for Mesopotamian spiny eel <i>(Mastacembelus mastacembelus </i>Banks & Solander, 1794). Mesopotamian spiny eel was caught from May to July 2017 in the Atat&uuml;rk Dam Lake and Euphrates Basin (meridians) in Şanliurfa, Turkey. During the study, the animals (n=10; 8 males, 2 females) were caught with gill nets (22 mm&times;22 mm, mesh size) and kept under natural lake water [temperature (22.00&ndash;23.60&ordm;C), oxygen (8.45&ndash;8.98 mg/l), pH (8.14&ndash;8.50) and salinity (0.22&nbsp;ppt)]. Semen was collected from eight males (</span></span><span lang="TR" new="" roman="" style="font-family:" times=""><span style="color:black">406.46&plusmn;166.68 g)</span></span><span lang="TR" new="" roman="" style="border:none windowtext 1.0pt; font-family:" times=""><span style="color:black"> weekly by abdominal massage after the hormonal injections of human chorionic gonadotropin treatment. </span></span><span lang="TR" new="" roman="" style="font-family:" times=""><span style="color:black">Sexual maturation and spermiation of </span></span><span lang="TR" new="" roman="" style="font-family:" times=""><span style="color:black">MSE</span></span><span lang="TR" new="" roman="" style="font-family:" times=""><span style="color:black"> males (n=8) were stimulated by weekly injections of human Chorionic Gonadotropin (hCG; </span></span><span lang="TR" style="color:black"><a href="https://www.ilac247.com/pregnyl-1500-iu-3-ampul-fiyat-i-0742" style="color:blue; text-decoration:underline" target="_blank"><span style="border:none windowtext 1.0pt; background:white; padding:0in"><span new="" roman="" style="font-family:" times=""><span style="color:black">Pregnyl</span></span></span></a></span><span lang="TR" style="border:none windowtext 1.0pt; background:white; padding:0in"><span new="" roman="" style="font-family:" times=""><span style="color:black">, Merck Sharp Dohme, Turkey</span></span></span><span lang="TR" new="" roman="" style="font-family:" times=""><span style="color:black">) [(1 International Unit (IU) hCG/body weight (g)/week]. </span></span><span lang="TR" style="background:white"><span new="" roman="" style="font-family:" times=""><span style="color:black">At the 7th week of hormonal treatment, milt from eight mature males was carefully collected by abdominal massage, avoiding contamination with urine and feces into the petri dish, 24 h after the hormone applications. </span></span></span><span lang="TR" new="" roman="" style="border:none windowtext 1.0pt; font-family:" times=""><span style="color:black">The motility of the collected spermatozoa and the spermatozoa density were evaluated on day of collection. Sixteen milliliter pooled ejaculate (2 milliliter per male) was split into two equal aliquots and diluted with the ArŞaDo extender (</span></span><span lang="TR" new="" roman="" style="font-family:" times=""><span style="color:black">NaCl (163mM), NaHCO₃ (9.4mM), MgCl₂ (0.84mM), CaCl₂ (8.26mM) and KCl₂ (18.16 mM)</span></span><span lang="TR" new="" roman="" style="border:none windowtext 1.0pt; font-family:" times=""><span style="color:black">) and the P1 (</span></span><span lang="TR" new="" roman="" style="font-family:" times=""><span style="color:black">NaCl (125 mM), NaHCO₃ (20 mM), MgCl₂ (2.5 mM), CaCl₂ (1 mM) and KCl2 (30 mM)) extenders. </span></span><span new="" roman="" style="font-family:" times=""><span style="color:black">After two weeks, straws were thawed in a water bath at 40&deg;C for 13 s and post-thaw sperm motility was immediately estimated subjectively. For the activation, saline solution</span></span> <span new="" roman="" style="font-family:" times=""><span style="color:black">(0.9% NaCl) was used.</span></span> <span lang="TR" new="" roman="" style="border:none windowtext 1.0pt; font-family:" times=""><span style="color:black">Sperm motility of thawing samples was significantly higher in ArŞaDo extender than in P1 extender (42.66&plusmn;1.17% <i>vs.</i> 32.96&plusmn;1.27%, respectively). The fertilization rate in ArŞaDo extender was higher than sperms preserved in the P1 extender (82.03&plusmn;1.94% vs. 73.43&plusmn;1.45%, respectively). In conclusion, the ArŞaDo extender improved the post-thawing spermatozoa motility percentage and fertilization rate in Mesopotamian spiny eel males.</span></span><span lang="TR" new="" roman="" style="font-family:" times=""><span style="color:black"></span></span></span></span></span></span> Cryopreservation, Diluent, Freezing extender, Mastacembelidae 619 633 http://jifro.ir/browse.php?a_code=A-10-2728-2&slc_lang=en&sid=1 Z. Doğu zaferdogu@harran.edu.tr 100319475328460045590 100319475328460045590 Yes Harran UniversiDepartment of Fisheries and Aquaculture, Bozova Vocational High School, Harran University 63850, Bozova, Şanlıurfa, Turkeyty Bozova Vocational High School F. Aral faral6@hotmail.com 100319475328460045591 100319475328460045591 No Independent Researcher, Çarşı PTT PK 138 Konya, Turkey E. Şahinöz e_sahinoz@harran.edu.tr 100319475328460045592 100319475328460045592 No Department of Fisheries and Aquaculture, Bozova Vocational High School, Harran University 63850, Bozova, Şanlıurfa, Turkey