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    Comparing ethylene glycol with glycerol and with or without dithiothreitol and sucrose for cryopreservation of bull semen in egg-yolk containing extenders
    (ACADEMIC PRESS INC ELSEVIER SCIENCE, 2014) Buyukleblebici, Serhat; Tuncer, Purhan Barbaros; Bucak, Mustafa N.; Tasdemir, Umut; Eken, Ayse; Buyukleblebici, Olga; Durmaz, Emre
    There are few studies performed for investigating the roles of different ratio and cryoprotectants with dithiothreitol or sucrose on sperm motility characteristics and antioxidant capacities of post-thawed bull spermatozoa. The objectives of this study were to compare glycerol (G) and ethylene glycol (EG) at different concentrations as cryoprotectants and dithiothreitol (D) or sucrose (S) (with/without) as antioxidants in Tris extender for cryopreservation of bull semen. Twenty-four ejaculates obtained from three bulls were included in the study. Each ejaculate was split into four equal aliquots and diluted using both of the Tris extenders with glycerol (5% or 7%) or ethylene glycol (3% or 5%). After that, each extenders were split into three equal aliquots and diluted using both of the dithiothreitol 5 mM or sucrose 25 mM, and control (without additives) was cooled to 4 degrees C and frozen in 0.25-ml French straws. when compared to control, different doses cryoprotectants and antioxidants addition no significantly increased the percentages of post-thaw sperm progressive and motitilities, acrosome abnormality and plasma membrane integrity (P > 0.05). However, EG3 + S yielded the greatest percentages of the total abnormality (P < 0.05). As regard to antioxidant activities G7 and EG5 led to lowest MDA activity with or without D or S but, these results were not supported to the GPx activity (P < 0.01). The sperm motion characteristics such as VAP, VCL, ALH and BCF gave significantly different results (P < 0.05). When compared the DNA integrity, different doses cryoprotectants without antioxidants addition significantly increased the percentages the tail intensity and tail moment (P < 0.05). There were no significant differences observed in non-return rates among all treatment groups (P > 0.05). (C) 2014 Elsevier Inc. All rights reserved.
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    Conception rate following timed artificial insemination protocols in dairy heifers synchronised by PGF2? and GnRH
    (ANKARA UNIV PRESS, 2011) Tasdemir, Umut; Yilmazbas-Mecitoglu, Gulnaz; Keskin, Abdulkadir; Karakaya, Ebru; Celik, Yakup; Guzeloglu, Aydin; Gumen, Ahmet
    This study aimed to develop a timed artificial insemination (TAI) protocol using PGF2? and GnRH with acceptable pregnancy rate in dairy heifers. Dairy heifers (n=290), aged between 13 and 26 months (mean 16.1 months), were used in this study. Heifers were synchronized with two PGF(2 alpha) administrations by 14 d intervals. After the second PGF(2 alpha), heifers were randomly assigned into two groups. In Group 1 (n=155), GnRH was given at 56h following 2nd PGF(2 alpha) and TAI was performed at 16-18h after the GnRH. In Group 2 (n=135), GnRH was administered at 72h after 2nd PGF(2 alpha), at the time of TAI. Ultrasonography was performed at both PGF(2 alpha) administrations to determine cyclicity, at the time of TAI to measure ovulatory follicle size, 7 d after TAI to determine ovulation, 31 and 62 d post-AI to determine pregnancy. Ovulatory follicle size at the time of TAI was not significantly different between groups (12.8 +/- 1.6 mm and 13.2 +/- 1.8 mm in group 1 and 2, respectively). Synchronization rate was similar in group 1 (85.2%;132/155) and in group 2 (91.1%;123/135). Conception rate (CR) at 31 d was not different in group 1(59.8%;79/132) and in group 2 (55.3%;68/123). Embryonic loss (7.6%; 6/79 and 7.4%; 5/68 in group 1 and 2 respectively) was not different. Gender ratio of the calves was found different between groups. Proportion of the female calves born were higher (P=0.03) in group 1 (63.3%; 38/60) than in group 2 (42.0%; 21/50). In conclusion, both protocols can be used in order to eliminate estrous detection in large dairy herds. Although GnRH administration at the time of TAI was found to be useful to reduce handling of heifers, GnRH can be applied 16-18 h before Alto achive higher female calves ratio in large dairy farms.
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    Cryopreservation of bull sperm: Effects of extender supplemented with different cryoprotectants and antioxidants on sperm motility, antioxidant capacity and fertility results
    (ELSEVIER, 2014) Buyukleblebici, Serhat; Tuncer, Purhan Barbaros; Bucak, Mustafa Numan; Eken, Ayse; Sariozkan, Serpil; Tasdemir, Umut; Endirlik, Burcu Unlu
    The objectives of this study were to compare glycerol (G) and ethylene glycol (EG) at different concentrations and trehalose (T) or cysteine (C; with/without) in Tris extender for cryopreservation of bull semen. Twenty-four ejaculates obtained from three bulls were included in the study. Each ejaculate was divided into four equal aliquots and diluted using both of the Tris extenders with G (5% or 7%) or EG (3% or 5%). After that, each extenders were divided into three equal aliquots and diluted using both of the 5 mM C or 25 mM T, and control (without additives) was cooled to 4 degrees C and frozen in 0.25 ml French straws. The addition of 3% and 5% EG without antioxidants resulted in the least Computer-Assisted Sperm motility Analysis (CASA) motility as compared with the other groups. Treatment with 25 mM Tin 3% EG beneficially effected acrosome morphology as compared with the other groups. Also, treatment with 3% EG with 25 mM T and 5% EG resulted in a greater rate of total abnormalities. Treatment with 3% G yielded a slightly greater percentage of membrane integrity by Hypo-Osmotic Swelling Test (HOST) assessment than that of the other groups. Treatment with 3% EG with 5 mM C resulted in the greatest concentration of malondialdehyde (MDA). The glutathione peroxidase (GPx) antioxidant activity was increased in the C-treatment groups when compared to the other groups. Treatment with 5% EG and 5 mM C resulted in less chromatin damage and detrimental impacts on tail moment. Treatment with 5% EG led to greater non-return rates of inseminated cows. However, this result was not considered to be statistically important. (C) 2014 Elsevier B.V. All rights reserved.