In vitro addition of docosahexaenoic acid improves the quality of cooled but not frozen-thawed stallion semen.

The research article discusses an experiment on the in vitro addition of docosahexaenoic acid (DHA) to assess its effect on the quality of both cooled and frozen-thawed stallion semen.

Experiment Overview

• The study was designed to measure the influence of DHA, a type of fatty acid, on the in vitro condition (outside the body) of stallion semen that has been either cooled or frozen-thawed.
• It was conducted in three stages, each with a unique method and goal. The success of the various stages was evaluated using markers such as total and progressive motility, membrane fluidity, acrosome integrity, and in the last experiment, lipid peroxidation levels.

Experiment 1

• The purpose of the first experiment was to understand the effects of DHA on frozen stallion semen.
• Three ejaculates were taken from each of the ten stallions, each sample diluted with vitamin E and varying amounts of DHA, and then frozen.
• The frozen samples were then thawed and examined for key qualities such as total motility, rapid progressive motility, acrosome integrity, membrane fluidity, and morphology.

Experiment 2

• Experiment 2 mirrored the first, but with a different procedure. Instead of adding DHA before freezing, it was added after the semen was thawed.
• Semen was collected from three stallions (three ejaculates each), the sample thawed, and then supplemented with vitamin E and DHA.
• The total and progressive motility were tested at specific time intervals (30, 60, 120 minutes) post-thaw, while viability, acrosome integrity, and membrane fluidity were evaluated at the 30-minute mark.

Experiment 3

• Experiment 3 veered from the first two, focusing instead on cooled stallion semen.
• In this third phase, semen was collected from five stallions (between one and three ejaculates each), diluted, and stored at a cold temperature of 4°C.
• The assessments were made at regular time intervals (1, 24, 48, and 72 hours) for total and progressive motility, viability, membrane fluidity, and this time, lipid peroxidation – a form of cell damage.

Results

• The data showed that adding DHA didn’t significantly alter the quality of the frozen semen (Experiment 1 and 2).
• However, the results revealed that the addition of DHA improved total motility, rapid progressive motility, and membrane fluidity in the cooled stallion semen (Experiment 3), evidencing the beneficial impact of this fatty acid on the quality of cooled semen.