Optimizing system for sperm quality evaluation using crystalloid diluent for pigeons (Columba livia domestica)

Abstract

Semen quality is a crucial factor for predicting fertility and hatchability in several avian species including pigeons.
To evaluate pigeon semen quality, prior dilution of semen was required due to its small volume with highly
concentrated spermatozoa. Conventional crystalloid solutions—Normal saline (NSS) and Ringer’s solution (LRS) are
common diluents for such a task; however, the unoptimized dilution rate of such diluents was a major cause
contributing to inaccurate semen quality evaluation. Due to the lack of such knowledge in pigeons this study aimed to
optimize the dilution rate of Normal saline (NSS) and Ringer’s solution (LRS) for pigeon semen quality evaluation. The
semen of a total of 20 male racing pigeons was collected and diluted in NSS or LRS at 12.5-, 25-, 50-, 100- and 200-fold
dilutions. Immediate percentages of sperm motility, progressive motility and viability were determined for each fold
dilution. The 12.5- and 25-fold-diluted semen were further evaluated at 0, 0.5, 1 and 3 h of storage. The results showed
that NSS and LRS rendered indifferent effects on immediate semen quality. However fold dilutions higher than 25
resulted in a great decline in semen quality both in NSS and LRS. Storage of 12.5-fold and 25-fold diluted semen resulted
in a marked decrease of semen quality as soon as 0.5 h; however, LRS was better than NSS in terms of maintaining
semen quality. This study thus supports immediate quality evaluation of pigeon semen—by which 12.5-25 folddilutions were suggested.