Effects of Adding Three Concentrations of Cold-Sensitive Nanoliposomes or Nanomicelles to Extender on Characteristics of Frozen-Thawed Bull Sperm.

INTRODUCTION

Nanoliposomes (NLs) are a rich source of phospholipids, including phosphatidylcholine, and can encapsulate and release hydrophilic and hydrophobic compounds, separately or simultaneously, to different cells.

OBJECTIVES

This study aimed to assess the impact of NLs or nanomicelles (NMs) on characteristics of frozen-thawed bull sperm.

METHODS

Semen samples were collected with an artificial vagina twice weekly from five bulls. Ejaculates that met minimum characteristics (n = 36) were pooled, extended with 1, 2, or 3% NL or NM, and cryopreserved. Frozen-thawed sperm were assessed regarding motility (computer-assisted sperm analysis), morphology, and plasma membrane integrity (eosin-nigrosin), plasma membrane functionality (HOST), acrosome integrity (Pisum sativum agglutinin), and fertility (in vitro fertilization).

RESULTS

Extender with 2% NL had the highest (p < 0.001) total motility (69.85 ± 0.92%), progressive motility (58.90 ± 0.81%), sperm with integrated membrane (68.88 ± 0.49%), sperm with active membrane (65.02 ± 0.53%), sperm with intact acrosome (75.28 ± 1.1%), and in an in vitro fertilization system, the highest rates of cleavage (68.06 ± 3.98%) and blastocyst formation (40.10 ± 3.44%).

DISCUSSION: NL provided better cryoprotection than NM for bull sperm. Supplementing the extender with NL could enhance bull semen cryopreservation.