The effect of the staining technique on morphological and morphometric parameters of boar sperm

Abstract

Sperm morphology and morphometry are important parameters in predicting fertility. Sperm are considered to be normal if the shape and size of the head, midpiece and tail fall within the classification for a given species. It is important to select the appropriate technique for staining the semen of a given species, because, as many authors have pointed out, some methods work well for one species but are not suitable for analysing another. The aim of the study was to assess the morphometric parameters of boar sperm following the use of different staining techniques and to verify the hypothesis that the staining technique affects the morphometric parameters of sperm. The staining method was found to significantly affect the dimensions of the boar sperm head. The semen stained by the SpermBlue technique had the closest morphometric sperm head parameters to those of the unstained sperm, so this technique, rather than the routinely used eosin and gentian complex, should be the leading technique in the evaluation of boar sperm morphometry. Silver nitrate staining reveals the structure of the sperm in the most detail; this method can be considered universal, and can be used independently or to supplement routine diagnostics. As the staining technique should interfere as little as possible with the structure of the sperm, while revealing its morphology in as much detail as possible, it is crucial to establish the natural dimensions of the unstained sperm head before determining the optimal technique and its reference values. The recommended or most commonly-used techniques are not always the best options for the staining and analysis of sperm of a given species.

Comparison of the structure of chinchilla sperm isolated from semen and from the tail of the epididymis

“…Some authors believe that the shape of the sperm head is genetically determined (Lavara, Vicente, & Baselga, ; Thurston, Watson, Mileham, & Holt, ). According to Kondracki, Wysokińska, Kania, and Górski (), the sensitivity of sperm to the type of stain used may be associated with genetic factors, which may be reflected in the dimensions of the sperm head (Czubaszek et al, ). There are studies indicating that the shape of the sperm head depends on certain factors that may arise during spermatogenesis.…”

“…Mammalian sperm are distinguished by their small size and compact structure, which sometimes makes it difficult to see the details of their morphology with a light microscope (Andraszek & Smalec, ). A search for techniques enabling the most accurate assessment of semen in terms of its functional features has revealed that a simple method of staining slides with silver nitrate captures more details of sperm structure than other routine methods (Andraszek, Banaszewska, & Biesiada‐Drzazga, ; Andraszek, Banaszewska, et al, ; Andraszek & Smalec, ; Banaszewska, Andraszek, Czubaszek, et al, ; Banaszewska, Andraszek, Szostek, et al, ; Banaszewska, Andraszek, Zdrowowicz, et al, ; Czubaszek, Andraszek, Banaszewska, & Walczak‐Jędrzejowska, ). Therefore, the aim of the work was comparison of the structure of chinchilla sperm isolated from semen and from the tail of the epididymis after staining with silver nitrate.…”

Morphometric Characteristics of the Spermatozoa of Blue Fox (Alopex lagopus) and Silver Fox (Vulpes vulpes)

“…The purpose of the study was a detailed comparison of the values of morphometric parameters of the sperm of two fox species blue fox ( Alopex lagopus ) and silver fox ( Vulpes vulpes ). The lack of definitive recommendations regarding sperm staining and the lack of reference morphometric values for canines prompted us to use staining to clearly identify the individual elements of the sperm structure [ 30 ]. The staining technique should interfere as little as possible with the cell structure, and, at the same time, should reveal as many details of its structure is possible.…”

“…Silver nitrate is an alkaline dye used to identify acidic chromatin proteins. It differentiates the sperm head more precisely than staining with eosin–gentian violet, which is routinely used for sperm evaluation [ 30 ]. This is probably due to the different composition of the cell membrane in the acrosomal and post-acrosomal parts of the sperm [ 31 , 32 ] and the presence in the post-acrosomal part of acidic proteins and nucleoli, which react positively with silver salts [ 23 ].…”

“…This is probably due to the different composition of the cell membrane in the acrosomal and post-acrosomal parts of the sperm [ 31 , 32 ] and the presence in the post-acrosomal part of acidic proteins and nucleoli, which react positively with silver salts [ 23 ]. In addition, silver nitrate staining is able to distinguish sperm structures between different species [ 18 , 30 , 33 , 34 , 35 , 36 ], birds [ 37 ], and insects [ 38 ], with precise measurements of the sperm structures made in each case. Silver nitrate staining can be used to observe differences in sperm structure between different species [ 23 , 33 ].…”