Dietary boron supplementation enhances sperm quality and immunity through influencing the associated biochemical parameters and modulating the genes expression at testicular tissue

Abstract

Introduction: Dietary boron improves immune and antioxidant status and calcium metabolism in mammals. However, till date the effects of dietary boron supplementation on male reproduction, especially on sperm production and sperm quality in farm animals are not documented.

Objective: The present study was aimed to investigate the influence of dietary boron on semen production, semen quality, immunity and molecular changes in the testis, blood and seminal plasma and to assess the interrelationship with other minerals in male goats.

Methodology: The study was conducted in 21 adult male goats divided into 3 groups (control, boron and selenium supplemented groups, n = 7 each). In boron group, boron was supplemented at 40 ppm and in selenium group, selenium was supplemented at 1 ppm over and above the basal level. In control group, only the basal diet was fed without supplementary boron or selenium. The feeding trial was carried out for 60 days. Selenium was taken as a positive control for the dietary boron supplementation experiment. Following feeding trials, the sperm concentration, kinematics and functional attributes, immunity and molecular level changes in the testis, biomolecular changes in the blood and seminal plasma and also interrelationship with other minerals were studied.

Results: The average sperm concentration (million/ml) and the total sperm production (million/ejaculate) were significantly (p < 0.05) increased in boron supplemented group when compared to selenium and control groups. The boron levels in blood plasma (r = 0.65) and seminal plasma (r = 0.54) showed a positive correlation with sperm progressive motility. Blood and seminal plasma metabolic biomarker namely, aspartate aminotransferase (AST) (p < 0.01) was significantly lower in the boron and selenium supplemented group than control, while alanine aminotransferase (ALT) (p < 0.05) was significantly lower in the boron supplemented group than selenium and control group. There was a significant increase in the mRNA expression of serine proteinase inhibitor (SERPIN) and interferon γ (IFNγ) in the testis of boron supplemented than the control group. Boron supplementation up-regulated the immune-regulatory gene, interleukin 2 (IL2) and antioxidant gene, catalase (CAT) in the peripheral blood mononuclear cells (PBMC). On contrary, toll-like receptor 2 (TLR2) mRNA expression was significantly (p < 0.05) down-regulated in boron and selenium supplemented groups.

Conclusion: The study revealed that dietary boron supplementation increased the sperm output, sperm motility and enhanced the immune and antioxidant defense capacity in male goats. The improved semen quality can be attributed to enhanced expression of testicular SERPIN, a crucial protein for the regulation of spermatogenesis process.