For commercial aquaculture, the obtainment of all-female salmonid populations is important in fish farms. After freezing process, variable spermatozoa maturity, higher sperm concentration, low sperm quality, and reduced fertilization success have been observed in sex-reversed female rainbow trout. For these reasons, the objective of this study was to assess effect of dilution rate and supplementation of a N-(2-Mercaptopropionyl)-Glycine (MPG)-based extender on sperm motility and fertilizing capacity of sex-reversed rainbow trout (Oncorhynchus mykiss). The supplementation of MPG [0 (control, 0), 1 mM; 2 mM; 4 mM] to extenders and dilution ratio (1:9, 1:15 and 1:25) were tested in sex-reversed female rainbow trout spermatozoa during cryopreservation. For thawing, the straws (0.5 ml) were placed in a water bath at 37°C for 30 s. Our results showed that the best concentration of MPG was 2 mM for post-thaw motility duration (120.67±9.07%), fertilization (62.67±3.10%) and hatching rate (54.33±3.10%) at 1:15 dilution rate. Overall, MPG provided improvements during cryopreservation process and could be used as protective agent.

Ascorbic acid (Vitamin C) is one of the important antioxidants, which naturally present in seminal plasma of fish. On the other hand, whether its effect may improve sperm quality following cryopreservation process still remains its uncertainty. Thus, the present study aimed to analyse the effect of different extenders supplemented with different ascorbic acid concentrations on post-thaw motility and fertility of frozen-thawed rainbow trout (Oncorhynchus mykiss) sperm. Selected sperm samples were pooled and diluted at 1:3 ratios with two different extenders (E) composing such as (E-1) 300 mM glucose, 10% egg yolk and 10% DMSO and (E-2) 0.6 mM sucrose and 10% DMSO. Each extender was supplemented with vitamin C at 1, 5 and 10 mM concentrations. Following dilution, the sperm was loaded into 0.25 ml straws and frozen in liquid nitrogen vapour. The straws were then plunged into liquid nitrogen for storage. Fertilization was carried out using the dry fertilization technique. Highest post-thaw motility (50±5.77) and fertilization (56±1.00) results were obtained with the extender-1 (E-1) containing 10% DMSO concentration. In conclusion, the present study indicated that addition of ascorbic acid to the extenders improved rainbow trout sperm motility resulting higher fertilization of the eggs.

This study is performed to determine some of sperm quality after applying freezing / thawing process. Thus, the aim of this study is to examine different cryprotective agents with additives in terms of their effects at different pH on the cryopreservation process of longspine scraper (Capoeta trutta). The present study, twelve media were prepared by mixing three different cryoprotectants (dimethyl sulfoxide (DMSO, (CH3)2SO); methanol (CH3OH); methyl glycol (MG, CH3O (CH2)2OH)) with an extenders (glucose) at four different pH (7.2, 7.6, 8.0 and 8.4) for longspine scraper semen. Considering the findings from the examination (The motility rate after thawing process and duration of motility obtained in DMSO as 81% and 20 min, in methanol as 73% and 12 min, in methyl glycol as 60% and 15 min.), we can conclude that the DMSO is the best freezing media in order to create new essays in cryopreservation for sperm of Capoeta trutta in the future.

In this study, it was aimed to determine the usability of different diluents and cry protectants in cryopreservation of Peking duck semen. Semen samples were collected from five male ducks, twice a week for four weeks, using the abdominal massage method. In the study, 40 semen samples were used. Semen samples from ducks were combined (mixed) after being evaluated individually. Mix semen volume (ml), density (×109 / mL), pH, motility (%) and vitality (%) values were determined as 1.84±0.04, 1.72±0.8, 6.88±0.29, 71.55±3.28 and 74.27±4.67 respectively. In the study, as cry protectant, Glucose I (GⅠ) containing 6%DMF (dimethylformamide), Tris-Glucose I (TI), Lactated Ringer's-Glucose I (LGI), Lactated Ringer's I (LI) and Glucose II (GⅠI) containing 5% DMSO, Tris-Glucose II (TII), Lactated Ringer's-Glucose II (LGII), Lactated Ringer's II (LII) were used as diluents. The mixed semen was divided into eight equal parts and 1:3 ratio diluent was added and equilibrated in straws for 90 minutes at + 4°C. The straws were first frozen to -80°C with liquid nitrogen vapour, and then stored in liquid nitrogen at -196°C. After freezing and thawing, the highest motility value was determined in diluent LGI with 41.91%. In other diluents used, the mortality values were determined as LII (33.10%), LGII (32.80%), LI (29.00%), GI (23.66%), TI (12.91%), GII (11.22%) and TII (6.90%). Vitality (%) values were determined as LGI (44.08%), LII (38.50%), LGII (35.10%), LI (33.58), GI (30.91%), GII (23.10%), TI (20.66%) and TII (14.80%) respectively. In this study, it has been determined that the lactated Ringer's-Glucose diluent containing 6% DMF is more advantageous in terms of semen vitality and mortality values when compared to other diluents and that it can be used for long-term storage of duck sperm.