Evaluation On The Sperm Viability, Mitochondrial Activity, Capacitation And Acrosome Intactness In Boar Semen During Long-term Liquid Storage

The cryopreservation of boar semen is still difficult for larpe-scale use due to the lowsPerm viabiIity fOllowing thawing and low fecundity rates after artificial inseminations. Liquidunfrozen semen omitS the process heezing and thawing, and can maintain good fertility evenwitb low numbers of sPerm in the inseminaion. However. the fertility of liquid semen isghually lost during the Storage. Therefore, proPer charactehaion of boar semen during theIong-term storage is of utmost impoboce.ln this study freshly ejaculated boar semen was diluted with equal volume of BeltSvilieThaw Solution (BTS), Androhep, KlEV or Zorlesco extender. the stOtal at l7'C for uP to l5days. SPerm quality in boar semen during the stmpe was evaluaed by examining viabilitywith SYBR-l4/Pl and HoechSt 33258 staining, mitochondrial activity using JC-l Staining,acrosome intactness by Coomassie blue staining, and capacitation statUs by CTC ndning.BOth SYBR-l4 and HoechSt 33258 were sensitive fOr detecting the sperm viability. Theviability assessed with SYBR-l4 was lower than that with Hoechst 33258. The viabilitydetermined by SYBR-l4 and HoechSt 33258 were 1ower than the Percentage of JC-1 -POsitivesperm. The percentages of viable sPerm and the sperm with active mitochondria during thestompe up to 8 days were slowly reduced. The percentags of JC-l-stained spermatozea were53.8t2. l0% for Zolesco and 57.7f l .60% for Androhep extenders on day l3 of storage.resePectively The resuIt5 from SYBR/PI, Hoechst 33258, JC-1 and Coomassie blue ndningwere highly correlnd (red.946l). But the percentag of acrosome-intact mpatOzoadetec1ed by Coomassie blue strining was higher than thaI of viable sPermatozoa evaluated bySYBR-l4/Pl, HoechSt 33258 and the sPerm with active mitochondria assessed by JC-lstalning. There were 1ess thAn l5% caPacitated sPermatozoa in the semen extended with BTS,Androhep and Zorlesco extenders during 9 day5 of stoop. However, most of viabIesPermatozoa became caPaitated from day l3 of stompe. The statUs of caPacitation andacrosome changed dramaticaly bo days 9-l4. and day l l, resPeCively There were 70%caPacitated sPermatozoa in boar semen extended with four eXtenders and 5tored uP tO l5 days.Sperm viability and the sPerm Percentage with intaCt acrosome and active mitOChondria wereover 50o/ in the semen extended by Androhep and Zorlesco extenders for l3 days, BTS for l0days and KIEV fOr 9 days, respectiveIy ln concIusion. the ed order of four extenders formaintaining sperm viabiIity, mitochOndrial activity and acrosome intaCiness was as followst4Androhep > Zorlesco >BTS > KIEVAdditionally, the aim of this stUdy was tO chaterize sPerm viability mitochondrialactivity, caPasitation status and asrosome integhty of ffeshly ejacuIated boar semen stored invitro for up tO 48 h under 4 "C, l5 "C, 20 'C and 39 'C. The method to assess sperm qualitywas the sarne as the above-mentioned methods. The resuItS assessed with SYBR-l4/PI,Hoechst 33258 and JC-l strining were highly cormlated (bo.98). In freshly ejaculated boarsemen, there were still 95.8t1 .3% boar sPermatozoa unstained by Hoechst 33258, 94.7tl .8%stained by SYBR-l4, and 95.7il.6% stained by JC-l. The sPerm viability dropPed shaIPlyduring the storage at 4oC. But in the 39 'C group, the drop was slower by 4 h. The viabilityduring the storage at both l5 "C and 20 "C was much bet'ter than that in both 4'C and 39 "C.The percentages of spermatozoa with active mitochondria detected by JC-1 and with intactacrosome evaluated by Coomassie blue staining were similar to the percentages of viabilityassessed by SYBR-l4/PI staining and Hoechst 33258 staining. A high percentage of boarspermatozoa became capacitated during more than 24 h Storage at l5 'C and 20"C. There were62.2rt.0% (l5"C) and 88.tal.2% (20'C) caPacitated spermatozoa by 48 h. Moreover, most ofthe capacitated spermatozoa were acrosome-intaCt. These resuItS suggest that SYBR-14/PI,Hoechst 33258 or JC-l s...