The effect of different levels of soybean lecithin on semen quality and sex ratio of Holstien bull sperm by Real-time qPCR technique

This study was designed to investigate the use of different levels of soybean lecithin in the Tris extender on semen quality and sex ratio using real-time qPCR technique.

Sampling of 4 Holstien bulls was performed once a week, then the appropriate samples were mixed. Samples of sperm (in 4 replications) were divided into three groups: zero, one and two percentage soybean lecithin. The qualitative parameters and the sex ratio of the semen were determined. Swim up technique was used to wash the semen and remove the dead cells. Moreover, the PLP and SRY genes were propagated to separate the specific fragments of X- and Y- chromosomes sequences. In this procedure, PAR was used as a housekeeping gene to normalize the gene expression data in real-time qPCR.

The results showed that swim up technique and different levels of soybean lecithin improve the semen quality. In addition, swim up technique significantly reduced PLP gene expression (0.75±0.11), against increased SRY gene expression (1.37±0.13). However, using of different levels of soybean lecithin did not change the sex ratio of the sperms.

In general, soybean lecithin is an appropriate substitute to animal sources and improves the quality of semen. Due to the limitations of using animal resources in bull extenders, the use of soybean lecithin as a plant source is suggested.