Blood Testosterone Level Affects Sex Ratio of Bull Semen

Volume 4 - Issue 1

Muna Kholghi², Jalal Rostamzadeh², Mohammad Razmkabir² and Farid Heidari¹*

Received: August 03, 2020;   Published: August 18, 2020

DOI: 10.32474/CDVS.2020.04.000177

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Abstract

Sex ratio has a direct impact on livestock economy and controling sex-linked genetically diseases. Offspring sex ratio is affected by such various factors. One of these factors is the Y/X-hromosome bearing sperm ratio in fertile specimen. This study was conducted to explore the effect of testosterone concentrations of blood and semen on the relative frequency of Y/X -chromosome bearing sperm in Holstein bovine semen. Blood and semen testosterone level were measured by ELISA technique. Quantitative real-time PCR was performed to estimate the ratio between sperm with Proteolipid Protein (PLP) and the Sex-Related Y (SRY) genes, locating on non-homologous regions of X and Y chromosomes. Blood and semen samples of 26 Holstein bovines were taken simultaneously. DNA was extracted from semen sampls and real-time PCR was performed to amplify the fragments of 90, 89, and 79 base pairs (bp) for PLP, SRY and PAR (as reference) genes, respectively. Wide variation was shown in Y- and X - chromosome bearing sperm, ranging between 18-82%. The least mean square of Y-bearing sperm (1.23±0.15) was significantly higher than that of X-bearing sperm (0.71±0.02). The correlation coefficients of SRY and PLP with blood and semen concentration of testosterone were 0.38, 0.47, -0.67 and -0.60, respectively. The results demonstrated that higher testosterone levels are probably associated with a higher proportion of Y- bearing sperm. A significant positive correlation (P<0.05) was detected between the age of cattle and the ratio of Y-bearing sperm. The testosterone concentration of blood and semen was positively correlated to the cattle age (P<0.05). The results may provide insights into the effects of paternal testosterone on sex ratio of sperm transferred to females.

Keywords: Real-time PCR, Semen, Sex ratio, Testosterone

Abstract| Introduction| Materials and Methods| Results| Discussion| Conclusion| Acknowledgments| References|