Browsing by Author "Ak, Kemal"

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Donmuş spermanın saklanması ve eritilmesi
(Uludağ Üniversitesi, 2003-03-17) Nur, Zekariye; Ak, Kemal; Bursa Uludağ Üniversitesi/Veteriner Fakültesi.
Günümüzde genetik kaynakların saklanarak gelecek yıllara aktarılması önemli bir konudur. Hayvancılık, biyoteknoloji, türlerin soyunun korunması ve klinik uygulamaları gibi geniş bir kullanıma sahip spermanın dondurularak saklanması süt sığırcılığı alanında büyük bir potansiyele sahiptir. Donmuş spermanın uygun koşullarda saklanması ve eritilmesi üzerine sun’i tohumlama alanında çalışanlar tarafından çok sayıda çalışma yapılmıştır. Bu derlemede donmuş spermanın saha koşullarında saklanması ve eritilmesi sırasında fertiliteyi düşürebilecek hatalı uygulamaların önüne geçmek için dikkat edilmesi gereken kritik noktalara değinilmiştir.
Effect of different thawing procedures on the quality of bull semen
(Ecole Nationale Veterinaire Toulouse, 2003-07) Ak, Kemal; Nur, Zekariya; Doğan, İbrahim; Soylu, Mustafa Kemal; Uludağ Üniversitesi/Veteriner Fakültesi/Dölerme ve Suni̇ Tohumlama Anabi̇li̇m Dalı.; 0000-0002-1438-221X; 0000-0003-1976-1814; AAH-2635-2021; R-8366-2018; 6508060684; 36762299000; 7003293300
The objective of this study was to evaluate effect of different thawing procedure to Hypo-Osmotic Swelling Test (HOST), motility and morphology of bull semen. Straw (0.25 ml) frozen semen from 4 Holstein bulls was used in this study. Post-thaw motility, morphology and hypo-osmotic swelling test (HOST) were carried out at 37degreesC for 30 sec, 50degreesC for 15 sec and 70degreesC for 5 sec. According to these protocols motility, defected acrosome, other morphological defects, total morphological defects, and swollen tail spermatozoa (HOST) values were 56.6 %, 56.7 %, 59.8 %; 3.7 %, 2.6 1.9 %; 10.7 %, 8.8 %, 5.6 %; 14.4 %, 11.5 %, 7.5 %; 37.1 %, 37.4 39.3 % respectively. Thawing protocol has affected all sperm characteristics (P < 0.05) except HOST. There was a high correlation between HOST values and motility (P < 0.01) but no correlation was observed between HOST and acrosome defects, other morphological defects and total morphological defects.
Effect of low temperature thawing procedure and post-thaw cold shock on frozen bull semen
(Polish Society of Veterinary Sciences, 2005-09) Ak, Kemal; İleri, İrfan Kamuran; Nur, Zekeriya; Sağırkaya, Hakan; Doǧan, İbrahim; Soylu, Mustafa Kemal; Uludağ Üniversitesi/Veteriner Fakültesi/Dölleme ve Suni Tohumlama Bölümü.; 0000-0002-1438-221X; AAH-8821-2021; 6508060684; 6602400461; 36762299000; 7003293300
The objective of this study was to investigate the effect of low temperature thawing and post-thaw cold shock application on sperm motility, as well as acrosomal and plasma membrane integrities of cryopreserved bull semen. Frozen semen was thawed in a water bath at 5-7 degrees C for 30, 60 or 90 s (low thawed groups), cold shocked (at 5-7 degrees C for 30, 60, 90 s) after thawing at 37 degrees C for 30 s (cold shocked groups), cold for 30 s (control group). The thawing procedure affected the percentages of motile spermatozoa (P < 0.001)and damaged acrosome (P < 0.001) while the bull factor affected the percentages of motile spermatozoa (P < 0.01) and damaged acrosome (P < 00.01). However, swollen tail spermatozoa rates were not affected by the the two factors. There was a significant interaction between thawing procedures and bulls in terms of the studies sperm parameters (P < 0.001). In conclusion, the percentages of motility, intact acrosome and swollen tail spermatozoa of the control group were higher than low-temperature thawed and post-thaw cold-shocked groups. These results indicate that frozen spermatozoa are significantly sensitive to lower temperature not only before but also after thawing.
The effects of a low dose of cabergoline on induction of estrus and pregnancy rates in anestrous bitches
(Elsevier, 2006-09-05) Cirit, Umut; Bacınoğlu, Süleyman; Kaya, Huriye Horoz; Taş, Muzaffer; Ak, Kemal; Cangül, İ. Taci; Uludağ Üniversitesi/Veteriner Fakültesi/Patoloji Anabilim Dalı.; AAB-4360-2021; 0000-0003-0537-2113; 6602486125
This is the first report of successful induction of normal estrus and ovulation in breeder bitches with as a low dose as 0.6 mu g/kg/day of cabergoline formulation marketed for use in women. Sixty-one pure breed bitches from various breeds were used in the study at their already determined periods of anestrus. Twenty-four dogs formed the control group, while 37 bitches were administered with two different doses of cabergoline (recommended dose group, n = 10, 5 mu g/kg/day and low dose group, n = 27, 0.6 mu g/kg/day). Induced estrus rates and mean treatment and proestrus durations of dogs in these two dose groups were compared. At the second phase of the study, the effects of 500 IU human chorionic gonadotropin (hCG) administered on days 1 and 3 of estrus induced by the low dose of cabergoline, on the duration of behavioral estrus, ovulation rates, pregnancy rates and the number of offspring were investigated. For this purpose, the dogs with signs of proestrus (22/27) following the treatment in the low dose group were assigned into two subgroups. Five hundred IU of hCG (Pregnyl, Organon, Turkey) was intramuscularly administered to eight of these dogs [low dose (hCG+) group] on days 1between days 8-45 and 4-48 (mean: 23.63 +/- 14.33 and 24.41 +/- 14.31 days), in the ratio of 80.0 and 81.5%, respectively (p > 0.05). In both dose groups, post-treatment interestrous intervals were significantly shorter than both those of the control group and their own pre-treatment interestrous intervals (p < 0.05). Ovulation rates, pregnancy rates and mean number of offspring delivered by the dogs in the recommended dose, low dose (hCG-), low dose (hCG+) and control groups were found to be similar (p > 0.05). However, the mean duration of behavioral estrus of the dogs in the low dose (hCG+) group was found to be significantly longer compared to dogs in all other groups (p < 0.05). In both dose groups, no correlation could be found between the anestrus stages and treatment durations (p > 0.05). Shortly, it has been concluded from the study that (1) normal and fertile estrus can be induced more economically in bitches during different stages of anestrus using as a low dose of 0.6 mu g/kg of cabergoline formulation marketed for use in women, and that (2) hCG injections on days 1 and 3 of the estrus induced by this method has no positive effects on the ovulation rates, pregnancy rates and the number of offspring per pregnancy. (C) 2006 Elsevier B.V. All rights reserved. and 3 of estrus. The remaining 14 dogs were not treated with hCG [low dose (hCG-) group]. An aqueous solution of cabergoline (Dostinex, Pharmacia, Italy) was orally administered until 2 day after the onset of proestrus or for a maximum of 42 days. Blood samples were taken daily from all treatment and 11 control bitches during the first five days of behavioral estrus to measure progesterone concentrations. In the recommended dose and low dose groups, estrus was induced.
Effects of adding bull seminal plasma to ram semen extehders on post-thaw spermatozoa motility and morphology
(Indian Veterinary Journal, 2004-07) Baran, Alper; Ak, Kemal; Ileri, Irfan Kamuran; Soylu, Mustafa Kemal; Uludağ Üniversitesi/Veteriner Fakültesi/Dölerme Ve Suni̇ Tohumlama Anabi̇li̇m Dalı.; 7003293300
Fertility of artificial insemination is relatively low when frozen semen is used in sheep (Ozturkler et al., 1999; Sanchez-Partida et al., 1992). Jones and Mann (1977) have suggested a relation between the lipid peroxidation formation in spermatozoa and quick decrease in motility and phospholipid loss in the membranes. Some researches agreed that dialyzed egg yolk, bull seminal plasma, milk and sodium sulphate could prevent spermatozoa from the post-thaw side effects of lipid peroxidation (Salamon and Maxwell, 1995; Aswort et al., 1994; Barrios et al., 2000). Jones and Mann (loc. cit.) claimed that egg yolk could decrease the peroxidation rate of ram spermatozoa when added to extenders but not as much as the bull seminal plasma. Researchers have found that bull spermatozoa can easily peroxidase due to the high level of unsaturated fatty acids bound to the phospholipids in the seminal plasma. The present study is planned to investigate the effects of bull seminal plasma in semen extenders during freezing of ram semen and its post-thaw motility and morphological characteristics.
Effects of different temperature treatments applied to deep stored bull semen on post-thaw cold shocked spermatozoa
(National Veterinary Research Institute, 2006) İleri, İrfan Kamuran; Ak, Kemal; Nur, Zekariya; Uludağ Üniversitesi/Veteriner Fakültesi/Üreme ve Suni Tohumlama Anabilim Dalı.; 0000-0002-1438-221X; AAH-2635-2021; 6508060684
Various treatments were applied to frozen semen during storage in containers with different nitrogen level and the effects of temperature changes due to these treatments on the resistance of spermatozoa against post-thaw cold shock were studied. Straws with frozen bull semen were placed into two identical field containers. One of these containers was the low nitrogen level container with 3 cm nitrogen level that is 2 cm above the lower end of straws and the other one was the high nitrogen level container with 17 cm nitrogen level that is 2 cm above the upper end of straws. Canister No. 1 in both containers served as control without any manipulation. Canister No. 2 were raised up to the neck of the container and kept at this level for 10 s. Canister No. 3 were taken out to such a position that their base was at the entrance of the container and kept at this level for 20 s. These manipulations were repeated 100 times for canisters No. 2 and 3, in both containers. Motility, defected acrosome, and hypo-osmotic swelling test were carried out at post-thaw (37 degrees C for 30 s) and after cold shock in a cold water bath (5-6 degrees C for 30 s). Post-thaw cold-shock was observed to cause significant damage to motility, membrane integrity, and acrosome integrity of spermatozoa. Low nitrogen level was not capable of protecting viability and morphological structures of spermatozoa. In container with low nitrogen level, raising the canister from the container and keeping it at this level for 20 s made the spermatozoa more sensitive to cold shock. In conclusion, container nitrogen level and canister manipulations had negative effects on both shocked and unshocked spermatozoa. Also the results provide evidence that not only canisters misuse but also low nitrogen level made spermatozoa more sensitive to post-thaw cold shock.
Effects of various cryoprotective agents and extender osmolality on post-thawed ram semen
(Bulletin of The Veterinary Institute in Pulawy, 2007) Ak, Kemal; Soylu, Mustafa Kemal; Nur, Zekariya; Üstüner, Burcu; Doğan, İbrahim; Sağırkaya, Hakan; Günay, Ülgen; Uludağ Üniversitesi/Veteriner Fakültesi.; 0000-0002-1438-221X; AAH-2635-2021; AAG-7238-2021; AAH-8821-2021; 7003293300; 6508060684; 18937724600; 36762299000; 6602400461; 55901087200
The influence of different extender osmolality levels and the presence of different cryoprotectants on the post-thawed semen's characteristics and post-thawed plasma membrane integrity of ram spermatozoa were studied. Ram semen was frozen with TRIS-egg yolk based extender according to two-step dilution procedures. The final concentrations of the cryoprotectants: 6% glycerol, 6% 1,2-propanediol, 62.5 mM sucrose, and 62.5 mM trehalose were studied in three different extender B osmolality levels (350, 375, and 400 mOsm). The osmolality affected significantly the post-thawed semen's motility, defected acrosomes (DA), total morphological defect (TMD), along with the sperm's plasma membrane integrity (HOST). Type of cryoprotectant exerted significant effect (P<0.001) on the post-thawed semen's motility, DA, TMD, and HOST. There was a significant interaction between the osmolality and cryoprotectant on the post-thawed motility, DA and TMD, but not on the HOST. In general, post-thawed motility, acrosomal, morphological, and membrane integrity of the semen frozen with semen extender at 400 mOsm were better than those of 350 and 375 mOsm, regardless of the type of cryoprotectant. Glycerol and 1,2-propanediol, compared to sucrose, trehalose, and control groups, did not protect the post-thawed acrosome and morphological integrity, though it did protect motility and HOST. It was concluded that glycerol based extenders with a high osmotic pressure (400 mOsm) was a better choice for ram semen freezing compared to sucrose, trehalose, and cryoprotectant free extenders. The detrimental effect of glycerol on DA and TMD could be overcome by combining glycerol with sugars and by increasing the osmotic pressure of the extender used for semen cryopreservation. Further research on the cryopreservation of ram semen should focus on the extender osmolality and combination of different cryoprotectants.