Application of Two Staining Methods for Sperm Morphometric Evaluation in Domestic Pigs

Area of Science:

• Animal reproduction
• Sperm morphology analysis
• Veterinary science

Background:

• Sperm cell dimensions and shape are critical for boar fertility.
• Standardized semen analysis requires consistent staining techniques.
• The influence of different staining methods on porcine sperm morphology is not fully understood.

Purpose of the Study:

• To evaluate the effect of two smear staining methods (eosin-nigrosin and eosin-gentian dye) on the dimensions and shape of domestic pig sperm cells.
• To determine if staining technique influences morphometric measurements in boar semen.

Main Methods:

• Analysis of 30 ejaculates from 15 domestic pigs (Duroc, Pietrain, and hybrid boars).
• Preparation of two microscopic slides per ejaculate, one stained with eosin-nigrosin and the other with eosin-gentian dye.
• Measurement of morphometric parameters (head length, width, area, perimeter; tail length; total length) for 600 sperm cells per staining method.

Main Results:

• Sperm cells stained with eosin-nigrosin exhibited significantly smaller dimensions (head length, head width, head area) compared to those stained with eosin-gentian dye.
• The staining method influenced not only sperm dimensions but also the proportions defining sperm shape.
• Observed differences indicate that staining technique affects the accuracy of morphometric sperm evaluation.

Conclusions:

• Porcine sperm size and shape parameters vary depending on the semen staining method used.
• Eosin-nigrosin staining consistently yields smaller measurements for boar sperm compared to eosin-gentian dye.
• The observed sensitivity of sperm measurements to staining methods may be linked to underlying genetic factors in boars.