Sperm cryopreservation is well known as a valuable method to preserve the genetic traits. Although many studies have established semen cryopreservation protocols, lack of studies were conducted to discover the differences of sperm proteome and functions between ejaculated and epididymal spermatozoa following to cryopreservation. Therefore, the objective of this study was to (i) evaluate the effect of cryopreservation on bull epididymal spermatozoa and (ii) discover the potential biomarkers, which have highly tolerance to freezing on bull epididymal spermatozoa. Our preliminary study demonstrated that spermatozoa from each bulls have different resistance on freezing during cryopreservation. We divided spermatozoa into two groups according to sperm motility following to cryopreservation; high freezing-tolerant spermatozoa (HFS) and low freezing-tolerant spermatozoa (LFS). Several sperm functional parameters, i.e. sperm motility/motion kinematics, speed parameters, viability, mitochondrial membrane potential, and capacitation status. Our results showed that all parameters except for motion kinematics and capacitation status had significant differences between HFS and LFS. Subsequently, two dimensional electrophoresis were conducted to compare the expression levels of sperm proteome between both groups. Three proteins {glutathione s-transferase mu 5 (GSTM5), voltage-dependent anion-selective channel protein 2 (VDAC2), and ATP stynthase subunit beta (ATP1B1)} were differentially expressed. Based on these results, we propose that epididymal spermatozoa from individual bull have different freezability upon cryopreservation and three differentially expressed proteins might be selected as a biomarker to predict high freezing-tolerant epididymal spermatozoa.

Processes of cryopreservation consists of three steps: dilution with the extender/cooling (Step 1), addition of cryoprotectant (Step 2), and freezing/thawing (Step 3) and spermatozoa are exposed different kind of environment and stress in each step. We categorized sperm samples as good freezablitiy (GF), damaged by cryoprotectant (DCP), and damaged by freezing (DF) and identified characteristics of each group in different step of cryopreservation. In Step 2, DCP was significantly decreased in motility, rapid speed and increased in slow speed. DF was significantly decreased in only motility whereas there were no significant difference between GF and DF and significantly higher than DCP in Step 2. Motility, rapid, medium speed of all group were significantly decreased in Step 3 and GF was significantly higer than other groups. AR pattern of all groups were significantly increased in Step 3 whereas GF was significantly lower than other groups. Additionally AR pattern of DF was significantly increased in Step 2. F pattern of DF and DCP were significantly decreased in Step 3. There no difference of B pattern in whole process. Mitochondrial activity of DCP was significantly decreased in Step 2 and mtichondrial activity of all groups were significantly decreased in Step 3. However mtichondrial activity of GF was higher than other groups. Viability result shows same significant difference with mitochondrial pattern. The present study compared with various sperm parameters in different groups which has different freezability. We defined different two types of group that damaged from different step of cryopreservation. DF and DCP is mainly damaged in Step 3 and Step 2 respectively. The results of current study suggest that various sperm parameters can be used as physical markers in freezability.

The purpose of this study was to examine the effect of growing stages of the Korean Native Striped Bull (KNSB) on the freezability and fertility of frozen-thawed semen. First, we investigated the total motility (TM) and progressive motility (PM) according to the diluent used for semen freezing. Second, we examined the effect of the age of KNSB on semen volume, TM and PM of fresh and frozen-thawed semen. Third, we examined the effect of frozen semen from the different age of KNSB on the fertilization rate, and the artificial insemination pregnancy rate. The diluents used in this experiment were Triladyl and Tris-egg yolk extender (EYE). Semen was collected from 5 KNSB in the growing stage (15 months) and 5 adult KNSB (36 months). When Triladyl or Tris-EYE extender was used for semen freezing, there was no difference of the mean TM and the mean PM. However, the mean TM was significantly higher in Bull No. 1885 than Bull No. 4283 ( <0.05). The mean volume of semen collected from the 15-month-old bulls (2.3 ml) was significantly lower ( <0.05) than that from the 36-month-old bulls (5.0 ml). The mean semen concentration was similar for the 15-month-old ( spermatozoa/ml) and 36-month-old ( spermatozoa/ml) bulls. For the 15-month-old and 36-month-old bulls, the mean TM of fresh semen were 93.7% and 88.3%, respectively, and the mean PM were 97.0% and 88.3%, respectively; the 15-month-old bulls showed a particularly high PM ( <0.05). For the 15-month-old and 36-month-old bulls, the mean TM (56.0% and 58.0%, respectively) and the mean PM (64.0% and 70.7%, respectively) of frozen-thawed semen did not differ. The development rates of embryos after fertilization and the pregnancy rate after artificial insemination using frozen-thawed semen did not differ according to the bull's age. In summary, semen volume differed according to the bull's age, but semen concentration and survival rate, the fertilization rate, and the pregnancy rate did not differ according to the stripe bull's age. Accordingly, semen from bulls in the growing stage can be collected and frozen for the preservation and multiplication of rare livestock.

This study was investigated to test in vitro-maturation rate of bovine follicular oocytes freezability of in vitro-matured bovine follicular oocytes with different stock solution in Glycerol and Propanediol, freezability of in vitro-rnatured bovine follicular oocytes on cryoprotectants, the viability of in vitro-rnatured bovine follicular oocytes by morphologically normal and FDA staining method. 1. The maturation rates of bovine follicular oocytes classified as grade A, B and C was 88, 63 and 21%, respectively. 2. Freezability of in vitro-matured bovine follicular oocytes on stock solution, TCM-199+5% FCS and m-PBS + 5% FCS was 61%(n=105), 48%(n=62) in M Glycerol and freeability of in vitro-matured bovine follicular oocytes on stock solution, TCM-199 +5% FCS and m-PBS + 5% FCS was 68%(n=112), 42%(n=57) in 1~2 Propanediol. The results indicate that freezability of in vitro-matured bovine follicular oocytes with different stock solution is important. 3. Freezability of in vitro-matured bovine follicular oocytes on cryoprotectants was Glycerol and PROH was 56%(n=167), 57%(n=169). The results indicate that PROH was superior to Glycerol. 4. The rates of morphologically normal IVM oocytes after thawing of cryopreserved oocytes with Glycerol and PROH were 39%(n=8), 65%(n=39), respectively. The results indicate that PROH was superior to Glycerol. 5. The fluorescent light intensity after thawing of cryopreserved oocytes classified with Positive, Partial-I, Partial-II, Negative with Glycerol and PROH. The results of FDA-positive 24%, 42%, Partial-I 17%, 10%, Partial- H 20%, 12%, FDA-negative 39%, 37%, and Partial-I, II, respectively.