Liquid Semen Characteristics of Indo-Pacific Bottlenose Dolphins (Tricops aduncus) after storage at 5°C

Abstract

Indo-Pacific bottlenose dolphins are potential models for the development of semen preservation in marine mammals. Lecithin-based commercial diluent is used for preservation of Indo-Pacific bottlenose dolphin liquid semen. This study aims to evaluate the characteristics of liquid semen of bottlenose dolphins after storage at 5°C in lecithin-based commercial diluents. Fresh semen from two 11,5 and 18-year-old Indo-Pacific bottlenose dolphins was collected once a week for 3 replicates. Fresh semen was evaluated microscopically and macroscopically. Semen with more than 70% sperm motility was divided into four tubes, each with and without centrifugation treatment. Semen was divided into concentrations of 100 × 106 ml-1 and 200 × 106 ml-1, then stored at 5°C for 4 days. Semen was stored in 15 mL tubes and kept in a refrigerator at 5 °C for 4 days. Evaluation was done every 24 hours, including motility, viability, and plasma membrane integrity (PMI) of sperm. Results showed a significant decrease (P < 0,05) in sperm quality every 24 hours of examination in all treatments. Liquid semen quality was maintained with motility ≥ 40% until day 2 after semen collection. Liquid semen preservation for Indo-Pacific bottlenose dolphin sperm can be done for a short storage period of 48 hours in all treatments with lecithin-based commercial diluent.