돼지인공수정용 정액액상보존제 Kp 의 개발에 관한 연구 I. Kp 의 pH 조절과 냉동정자에 의한 보존성 검정

A Study on Development of Boar Semen Extender Kp for Swine AI I. Stabilization of pH Change and In Vitro Survival of Frozen-Thawed Boar Sperm in Kp Extender

본 연구는 독자 개발한 돼지액상정액희석제 Kp(한국생명과학연구소)에 pH를 안정화하여 보존 중 정자의 운동성을 유지시킬 수 있도록 EDTA, Tris, Citrate buffer의 적정 첨가농도를 결정하고자 실시하였다. Basic Kp와 BTS (Mini-tube, Germany; BT-Sg), BTS (Tri-bio, USA; BTSa), Modena (SGI, USA)를 17$^{\circ}C$ 에서 각각 보관한 경우 모든 희석액에서 시간 경과에 따라 pH가 증가하였고, Basic Kp 는 희석 당일의 pH가 다른 희석액에 비해 높게 나타났는데 이것은 돼지액상정액의 생리적인 pH인 6.8~7.5에 비해서도 높은 수준이었다. 정액내의 pH 저하를 방지해 주고 정액의 생리적인 pH를 유지하기 위하여 Basic Kp에 EDTA, Tris, Citrate buffer를 단계적으로 첨가하면서 시간 경과에 따른 pH 변화를 살펴 본 결과 1.25g /L EDTA, 1.42g /L Tris, 1.00g /L Citrate를 첨가한 경우 (Modified Kp) pH는 l일째 6.88에서 6일째 7.33으로 유지되었다. 특히, Modified Kp에 첨가된 buffer 의 농도는 Modena와 다른 희석제에 첨가된 농도에 비해 1/2 에서 1/4 정도로 낮은 수준이었다. Modified Kp 와 Basic Kp, BTSg, BTSa 및 Modena로 냉동-융해된 돼지 정자를 희석하여 보존한 경우 정자의 운동성은 Modified Kp가 다른 희석액에 비해 유의하게 높게 나타났다(87.0% vs. 71.0~48.0% in day 1; 13.3% vs. 6.3~0% of day 6), 이상의 결과를 종합해 볼 때, Modified Kp는 낮은 농도의 EDTA, Tris, Citrate buffer 첨가에도 불구하고 돼지정자의 생리적인 pH 수준을 잘 유지할 수 있었으며, 수입되어 냉동-융해된 돼지 정자에 사용하는 희석제 BTSg, BTSa, Modena 보다도 정자의 운동성에 효과적이었다.

Boar semen extender Kp (Hankook Life-Science, Korea) was newly formulated by authors. This study was carried out to investigate the optimal concentrations of EDTA, Tris and citrate buffers in the Kp extender (Basic Kp) on the pH change during storage. And then the motility of boar sperm with the Kp pH stabilized (Modified Kp) was compared with those of commercial products imported into Korea such as BTS (Mini-tube. Germany; BTSg), BTS (Tri-bio, USA; BTSa) and Modena (SGI, USA). The pH values of all extenders were increased gradually with the storage days. Especially, the initial pH of Basic Kp was higher than that of BTSg, BTSa and Modena, and also higher than physiological pH of boar sperm (6.8∼7.5). When Basic Kp was added with various concentrations of EDTA (0, 0.63, 1.25 ＆ 2.37g/L), Tris (0, 0.18, 0.35, 0.71 ＆ 1.42g/L) and Citrate (0, 0.75, 0.81, 1.00, 1.25 ＆ 1.50g/L) buffers for pH down-regulation and stabilization of pH, the group added with 1.25g EDTA, 1.42g Tris and 1.00g Citrate well maintained the neutral range of pH during storage (6.88 at day1 to 7.33 at day6 in Modified Kp), Especially, the concentrations of the buffers added in Modified Kp were lower, until 1/2∼1/4 ranges, than those in Modena and other extenders. The motility of frozen-thawed boar sperm diluted with Modified Kp was significantly higher than that of Basic Kp, BTSg, BTSa and Modena (87.0% vs. 55.0∼71.0% at day1; 13.3% vs. 0∼6.3% at day6), Conclusively, Modified Kp in this experiment was kept the favorable physiological conditions in spite of low concentrations of the buffers and motility of frozen-thawed boar sperm was obtained better than that of Basic Kp and other commercial products such as BTSg, BTSa and Modena.