Evaluation of different laboratory challenge of sperm resistance on the plasma membrane integrity and sperm chromatin from different bulls

• Grant number: 13/02852-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2013
• End date: December 31, 2013
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Reproduction
• Principal Investigator: Letícia Zoccolaro Oliveira
• Grantee: Vinícius Rozales Martins
• Host Institution: Pró-Reitoria Acadêmica. Centro Universitário de Rio Preto (UNIRP). Sociedade Riopretense de Ensino e Educação. São José do Rio Preto , SP, Brazil

Abstract

The aim of this study is to compare different laboratory tests in order to evaluate the effect of some laboratory challenges on in vitro quality of frozen-thawed semen, and to evaluate several sperm characteristics after the respective procedures. It will be used frozen semen doses from five different bulls and 2 batches for each bull will be evaluated. For each batch, three repetitions of each experimental design will be performed. Hence, for each semen doses, the following procedure will be performed: a 0.5 mL semen sample will be thawed at 37ºC for 30 sec (control group). Then, the following laboratory tests will be performed: sperm motility and vigor, Hypo-osmotic swelling test, sperm morphology and assessment of sperm chromatin condensation and morphometry by Toluidine Blue stain. Then, an aliquot of 200 uL of the control sample will be incubated in a water bath at 38°C for 2 h (thermal challenge Group; GDT) and another aliquot of 200 uL of control sample will be centrifuged at 500 x g in Percoll gradient 45% by 5 minutes (centrifugation challenge Group; GDC). In addition, the diluted and centrifuged semen (GDC) will be further submitted to thermal challenge, being incubated in a water bath at 38°C for 2 h (centrifugation + thermal challenge Group; GCDT). At the end of each challenge (GDT, and GCDT GDC), the same laboratory tests performed for the control group will be repeated. Finally, at the end of the present work, the results of control, GDT, GDC and GCDT groups will be compared between bulls in order to evaluate, for each sire, which was the most damaging laboratory challenge to the seminal quality. (AU)