Tavşan Embryolarının İn Vitro Kültüründe Sığır Serumunun Kullanılabilirliği.

Sunulan çalışmada tavşan embryolarının in vitro kültürleri için amino nitrojen ihtiyaçlarını karşılamada BSA'ya alternatif olarak ısıtılarak inaktive edilmiş (HTBS) sığır serumunun kullanılabilirliği ve embriyonal gelişime etkileri araştırıldı. Kültürde temel medium olarak TCM 199 kullanıldı. Bu mediuma bir grupta (A) %20 oranında (hacim/hacim)sığır serumu, diğer grupta ise (B) %1,5 oranında (ağırlık/hacim) BSA katıldı. Kazanılan 24 saatlik tavşan embriyoları bu mediumda 96 saat süresince kültüre edildi. Sonuç olarak 96 saatin bitiminde, A mediumunda %83,87 oranında, B mediumunda ise %75,86 oranında gelişme sağlandı. Buna göre sığır serumunun BSA'ya göre daha iyi derecede gelişim sağpladığı belirlendi (p<0,05). Bunun yanı sıra sığı8r serumlu medimda kültürün her aşamasında daha fazla sayıda embryonun daha ileri safhadaki gelişim durumlarına ulaştığı kaydedildi

Effect of low temperature thawing procedure and post-thaw cold shock on frozen bull semen

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

Effects of different temperature treatments applied to deep stored bull semen on post-thaw cold shocked spermatozoa

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

New strategies to improve the efficiency of the ovsynch protocol in primiparous dairy cows

The aim of this study was to create new strategies to increase the pregnancy rate in "ovsynch protocol" treatment. Two programs for synchronisation of ovulation and for synchronisation of ovulation and oestrus, similar to the ovsynch, were developed for the use in lactating primiparous dairy cows. Lactating Holstein-Friesian cows were randomly divided into five treatment groups: the GPG group (ovsynch) was treated with GnRH on day 0, PGF (PGF2 alpha) on day 7, and received the second dose of GnRH 48 h later; the groups -7PGPG and 2- PGPG received the same treatment as the GPG group, but were given an additional injection of PGF 7 and 2 d before the start of the GPG treatment; respectively, the PG9PG group received the same treatment as the -2PGPG group, with the modification that the first GnRH injection was given simultaneously with the first PGF on the 2(nd) d; the GPEG group received the same treatment as the GPG group, but was injected an additional oestradiol propionate (EP) 24 h after the PGF. Plasma progesterone concentrations were determined at the days of the first hormone injection and the last PGF injection. Ovulation rates after the first GnRH and last PGF injections were calculated and presumptive sizes of the follicles on the last PGF injection day were determined in all the cows by rectal palpation. Cows detected to be at oestrus in 72 It after the last PGF injection was inseminated between the 8(th) and 12(th) h of their oestrus. Cows not detected to be in oestrus by 72 It after the last PGF received timed artificial insemination (TAI). While the ovulations mostly occurred in the GPG, GPEG, and -7PGPG groups at a period between the 48(th) and 96(th) h after the last PGF injection, the ovulations had shifted and occurred between 72 and 120 h, with 66.7% of all ovulations recorded between 72 and 96 It in the -2PGPG group. In the PG9PG group, ovulations took place dispersedly between the 0(th) and 120(th) h after the last PGF injection. The pre-synchronisation treatment (-7PGPG) by a PGF injection 7 d prior to the ovsynch protocol did not enhance the ovulation or pregnancy rates. The pre-synchronisation treatment by PGF injected 2 d before the ovsynch protocol, increased the number of cows that ovulated after the first GnRH injection (88.9% vs. 38.9% P 0.05). Adding EP to GPG (GPEG), enhanced the expression of oestrus (P 0.05). In conclusion, the -2PGPG and GPEG treatments are potentially new methods for routine synchronisation of ovulation and oestrus and/or ovulation, respectively, in primiparous Holstein-Friesian cows