T.A.E. Stout

Publications (9)4.17 Total impact

• Article: Effect of pre-freeze semen quality, extender and cryoprotectant on the post-thaw quality of Asian elephant (Elephas maximus indicus) semen.

  P Imrat, P Suthanmapinanth, K Saikhun, S Mahasawangkul, E Sostaric, P Sombutputorn, S Jansittiwate, N Thongtip, A Pinyopummin, B Colenbrander, W V Holt, T A E Stout
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  ABSTRACT: Semen cryopreservation and artificial insemination (AI) are potentially valuable methods for supporting the breeding management of endangered species like the Asian elephant. Cryopreservation of Asian elephant semen has however proven problematic with respect to maintenance of both adequate semen quality and fertility post-thaw. In this study, nine ejaculates from three adult bulls were used to compare the influence of extender (TEST versus INRA96(®)) and penetrating cryoprotectants (3% glycerol, 5% glycerol and 4% methylformamide) on post-thaw semen quality. We demonstrate that not only the freezing process, but also the quality of the semen before freezing, significantly influences the freezability of Asian elephant semen. Pre-freeze motility, viability, semen volume, semen pH, sperm concentration and the incidence of sperm mid-piece and tail abnormalities all significantly (p<0.05) affected post-thaw semen quality. While extender and cryoprotectant did not significantly affect any of the above semen quality parameters post-thaw, the skim-milk based extender (INRA96(®)) preserved DNA integrity better (p<0.05) than the egg yolk extender (TEST). Considerable between-ejaculate variation in all post-thaw semen quality parameters was also noted. It is concluded that strict criteria for semen quality is essential for the selection of Asian elephant bull ejaculates suitable for cryopreservation; stricter initial selection should improve the mean post-thaw quality.
  Cryobiology 11/2012; · 2.06 Impact Factor
• Source

  Available from: William Holt

  Article: Effect of cooled storage on quality and DNA integrity of Asian elephant (Elephas maximus) spermatozoa

  P. Imrat, S. Mahasawangkul, J. Gosálvez, P. Suthanmapinanth, P. Sombutputorn, S. Jansittiwate, N. Thongtip, A. Pinyopummin, B. Colenbrander, W. V. Holt, T. A. E. Stout
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  ABSTRACT: Artificial insemination (AI) is a potentially useful tool for breeding captive elephants because it facilitates efforts to minimise inbreeding. However, cooled storage of elephant semen markedly reduces fertility. This study compared the effects on semen-quality parameters, including sperm DNA fragmentation, of storing elephant semen at 4°C or 15°C in a commonly-used diluent (TEST) or a diluent developed to protect against sperm DNA damage (BullMax). Storing elephant semen for >24 h in either extender at either temperature resulted in decreases in sperm motility, viability, acrosome integrity and DNA integrity (P < 0.05); the decrease in motility was especially rapid. A subjective impression of circular sperm movement in TEST was confirmed by a higher curvilinear velocity and amplitude of lateral head displacement, but lower straight-line velocity and linearity than in BullMax. Initial percentages of spermatozoa with fragmented DNA (%SDF) did not differ between extenders or temperatures, but the rate of increase in %SDF during a 48-h incubation at 37°C was higher in TEST than in BullMax (P < 0.05). In conclusion, BullMax allows more linear movement and better preserves DNA stability of stored elephant spermatozoa than TEST. Sperm DNA stability during incubation at 37°C is a promising, discriminative parameter for selecting semen storage conditions of bulls for elephant AI.
  Reproduction Fertility and Development 04/2012; · 2.11 Impact Factor
• Article: Effect of cooled storage on quality and DNA integrity of Asian elephant (Elephas maximus) spermatozoa

  P. Imrat, S. Mahasawangkul, J. Gosálvez, P. Suthanmapinanth, P. Sombutputorn, S. Jansittiwate, N. Thongtip, A. Pinyopummin, B. Colenbrander, W. V. Holt, T. A. E. Stout
  [show abstract] [hide abstract]
  ABSTRACT: Artificial insemination (AI) is a potentially useful tool for breeding captive elephants because it facilitates efforts to minimise inbreeding. However, cooled storage of elephant semen markedly reduces fertility. This study compared the effects on semen-quality parameters, including sperm DNA fragmentation, of storing elephant semen at 4°C or 15°C in a commonly-used diluent (TEST) or a diluent developed to protect against sperm DNA damage (BullMax). Storing elephant semen for >24 h in either extender at either temperature resulted in decreases in sperm motility, viability, acrosome integrity and DNA integrity (P < 0.05); the decrease in motility was especially rapid. A subjective impression of circular sperm movement in TEST was confirmed by a higher curvilinear velocity and amplitude of lateral head displacement, but lower straight-line velocity and linearity than in BullMax. Initial percentages of spermatozoa with fragmented DNA (%SDF) did not differ between extenders or temperatures, but the rate of increase in %SDF during a 48-h incubation at 37°C was higher in TEST than in BullMax (P < 0.05). In conclusion, BullMax allows more linear movement and better preserves DNA stability of stored elephant spermatozoa than TEST. Sperm DNA stability during incubation at 37°C is a promising, discriminative parameter for selecting semen storage conditions of bulls for elephant AI.
  Reproduction, Fertility and Development.
• Article: Effect of cooled storage on quality and DNA fragmentation of Asian elephant sperm

  P. Imrat, S. Mahasawangkul, J. Gosálvez, P. Suthanmapinanth, S. Thongtipsiridech, A Pinyopummin, B Colenbrander, W. Wolt, T.A.E. Stout
• Article: Total antioxidant levels in seminal plasma correlate negatively with semen quality in Asian elephants

  T. Imrat, S. Srihawong, S. Mahasawangkul, P. Suthanmapinanth, K. Kornkaewrat, K. Boonprasert, P. Homkong, C. Tirawatavanich, S. Thongtipsiridech, B Colenbrander, A Pinyopummin, T.A.E. Stout
• Article: Exogenous GnRH stimulates a testosterone release response in adult Asian bull elephants before but not soon after musth.

  C. Somgird, C. Thitaram, J L Brown, S. Mahasawankul, K. Boonprasert, P. Boongird, B Colenbrander, T.A.E. Stout
• Article: Efficacy of GnRH vaccination for suppressing musth and aggressive behaviour in male Asian elephants

  R.C. Rajapaksa, I.P.G. Dissanayaka, C. Somgird, C. Thitaram, A. Sirimalaisuwan, P.G.A. Pushpakamura, B Colenbrander, B. Perera, T.A.E. Stout
• Source

  Available from: Johannes A Lenstra

  Article: Genetic diversity among wild elephants (Elephas maximus maximus) in Sri Lanka, based on mitochondrial control region analysis.

  A.A. Amarasinghe, P. Alexander, P. Pushpakumara, N. Jayasekara, B. Perera, W. Waijwalku, S. Dejchaisri, C. Thitaram, B Colenbrander, T.A.E. Stout, J A Lenstra
• Article: Genetic diversity of Asian elephants (Elephas maximus) in Thailand as determined by mitochondrial genome haplotype analysis

  S. Dejchaisri, S. Thongchai, C. Thitaram, C. Savini, S. Mahasawangkul, S. Wanghonsa, S. Krataichan, K. Nitaya, S. Panitanato, D. Thumasanukul, N. Bhumpakphan, R. Sukmasuang, A Pinyopummin, S. Thongtipsiridej, W. Waijwalku, B Colenbrander, T.A.E. Stout, J A Lenstra