Sperm traits on in vitro production (IVP) of bovine embryos: Too much of anything is good for nothing

PLoS One. 2018 Jul 10;13(7):e0200273. doi: 10.1371/journal.pone.0200273. eCollection 2018.

Abstract

Sperm samples used on fertilization strongly influence the in vitro production (IVP) rates. However, sperm traits behind this effect are not stated consistently until now. This study aimed to evaluate the isolated and combined effect of some sperm traits (MB: total motility before Percoll® gradient, MA: total motility after Percoll® gradient, AI: acrosome integrity, MI: membrane integrity, MP: mitochondrial membrane potential, and CR: chromatin resistance) on IVP rates. This is the first study focusing on the isolated effect of distinct traits. For this purpose, the experiment was divided in three steps. In first step, to study behavior of traits sperm samples (n = 63 batches) were analyzed and ranked based on each trait. In second step, samples ranked were selected from target ranks regions and allocated in groups of four to five batches, creating Higher and Lower groups, according to two different approaches. One aimed to form groups that differed to all sperm traits simultaneously (effect of combined traits). The other aimed to form groups that differed only to a single sperm trait while no differences were observed for the remaining traits (effect of each isolated trait). In third step, for each group successfully formed in step 2, sperm samples were individually and prospectively used for IVP. Cleavage, embryo development and blastocyst rates were recorded and compared between Higher and Lower of respective trait groups. Surprisingly, evaluation of isolated effects revealed that lower levels of MB, AI and MP resulted in higher embryo development and blastocyst rates (p<0.05), which was not observed on cleavage rate. We conclude that sperm traits strongly influence embryo development after in vitro fertilization (IVF), affecting the zygote competence to achieve blastocyst stage. Individually, levels of MB, AI or MP could be some of the key traits that may define IVP efficiency on current systems of embryo production.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acrosome / physiology
  • Animals
  • Blastocyst / physiology
  • Cattle / embryology*
  • Chromatin / metabolism
  • Cleavage Stage, Ovum / physiology
  • In Vitro Techniques
  • Male
  • Membrane Potential, Mitochondrial
  • Povidone
  • Silicon Dioxide
  • Sperm Motility
  • Spermatozoa / physiology*
  • Zygote / physiology

Substances

  • Chromatin
  • Percoll
  • Silicon Dioxide
  • Povidone

Grants and funding

Funded by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Grant number: 2013/07940-9 (AFPS), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); (AFPS), Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Grant number: 2016/15147-5 (MEODAA). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.