This study is the first of its kind, offering novel insights into the dynamics of androgen hormones and the response of semen quality to herbal feed supplementation in breeding bulls.
Effects of herbal feed supplementation on plasma androgen dynamics
The testosterone levels, whether within individual treatment groups (different cycles) or across all groups, did not reach statistical significance (Fig 1). This suggests that the administered herbal treatment did not induce substantial alterations in testosterone concentrations during the course of the study.
Testosterone is a primary androgen hormone crucial for regulating spermatogenesis, the process of sperm production. It stimulates the proliferation and maturation of sperm precursor cells into functional spermatozoa (
Smith and Walker, 2014). Adequate testosterone levels are essential for maintaining sufficient sperm count and semen quality
(Grande et al., 2022). While some evidence suggests that certain herbs and extracts can increase testosterone levels in men
(Smith et al., 2021), our study found no significant changes in blood testosterone levels in bulls, possibly due to variations in dosages and types of herbs used.
Dihydrotestosterone (DHT) levels exhibited a significant reduction (p<0.05) in groups G-II and G-III following 60 days of herbal feed supplementation at doses of 35 and 70 g/day/bull, respectively, corresponding to the first sperm cycle (Fig 2). This significant reduction was sustained at 120 days compared to the baseline levels at day 0; however, non-significantly higher values were observed at 120 days as compared to 60 days.
DHT is an active metabolite of testosterone and acts as a potent androgen in the male reproductive system, contributing to the development and maintenance of secondary sexual characteristics
(Cai et al., 1994). It is primarily synthesized from testosterone by the action of the enzyme 5α-reductase. It is possible that certain phytochemicals within these herbal supplements might have influenced the activity of 5α-reductase or the conversion of testosterone to DHT, leading to decreased DHT concentrations in the bloodstream. Elevated levels of DHT are known to stimulate oxidative stress
(Ji et al., 2022) and thus may have negative impacts on semen quality.
Herbal medicines have been studied for their potential to reduce DHT levels. Some herbal remedies have antiandrogenic properties, which may inhibit DHT production or activity (
Dhariwala and Ravikumar, 2019;
Csikos et al., 2021). However, it is important to note that research on this topic is limited to androgenetic alopecia and the effectiveness of herbal medicine in reducing DHT levels and improving semen quality parameters remains limited.
Dehydroepiandrosterone (DHEA) levels among all groups of bulls showed no significant difference within treatment groups or across different sperm cycles (Fig 3).
DHEA, a precursor hormone synthesized by the adrenal glands, can be enzymatically converted into both testosterone and estrogen within the body. Elevated levels of circulating plasma DHEA have been proposed as an indicator of human longevity, with diminished DHEA levels associated with various pathophysiological conditions such as adrenal insufficiency, severe systemic illnesses, acute stress and anorexia
(Nenezic et al., 2023). While the research surrounding DHEA’s impact on semen quality is less extensive compared to testosterone and DHT, it is plausible that DHEA may indirectly influence fertility by contributing to the hormonal environment necessary for normal reproductive function.
The levels of Androstenedione remained relatively stable among the groups following 60 days (I cycle) and 120 days (II cycle) of herbal feed supplementation (Fig 4). Statistical analysis revealed no significant variations in Androstenedione levels, suggesting that the herbal feed had minimal impact on this particular hormone over the specified durations.
Androstenedione is a precursor hormone that serves as a crucial intermediate in the biosynthesis of both testosterone and estrogen. It plays a significant role in regulating secondary sexual characteristics, muscle development and bone density
(Badawy et al., 2021).
Importantly, the assessment of reproductive hormones, holds a central role in the diagnosis and management of male fertility disorders. However, the correlation between androgens and sperm quality in bulls has produced inconclusive findings across various studies
(Javed et al., 2000; Rajak et al., 2014). Therefore, it is imperative to conduct further research to establish a comprehensive framework for discerning hormone-associated bull infertility, thereby facilitating the formulation of efficacious treatment protocols.
Effects of herbal feed supplementation on semen quality parameters of breeding bulls
The effects of herbal feed supplementation on quality parameters of fresh semen in Frieswal breeding bulls are presented in Table 1. After 60 days (Cycle I) and 120 days (Cycle II) of supplementation, a statistically significant (p<0.05) increase in semen volume was observed in G-II and G-III, in comparison to the control group (G-I). However, no significant changes were observed between in G-II and G-III.
Similarly, a notable trend of significant (p<0.05) increase was observed in the initial progressive motility of spermatozoa. This finding indicates that, following 60 days and 120 days of herbal feed supplementation, bulls in G-II and G-III exhibited a statistically significant (p<0.05) improvement in the forward movement compared to the control group.
After 60 days (Cycle I) and 120 days (Cycle II) of supplementation, bulls in G-II and G-III exhibited a statistically significant (p<0.05) improvement in sperm viability compared to the control group (G-I). Specifically, viability increased from 48.16±3.20% in G-I to 55.12±3.45% and 57.66±3.72% in G-II and G-III, respectively.
Similarly, there was a significant (p<0.05) reduction in sperm abnormality in G-II and G-III, with values dropping to 8.94±1.62% and 8.24±2.15%, respectively, compared to 9.23±2.15% in the control group. These findings suggest that the herbal feed supplementation not only enhances sperm motility and volume but also improves sperm quality by increasing viability and reducing abnormality.
Herbal feed supplements have been explored for their potential benefits in reproductive health. Safed Musli (
Chlorophytum borivilianum), rich in steroidal saponins, alkaloids, proteins, carbohydrates, fiber, vitamins and minerals, has shown potential in enhancing sexual performance and supporting male reproductive health
(Khanam et al., 2013). Kali Musli (
Curculigo orchioides), containing steroidal saponins, phenolic compounds, flavonoids, tannins and alkaloids, has been associated with improvements in conditions such as asthenozoospermia, oligospermia, hypospermia and teratospermia
(Chauhan et al., 2010). Ashwagandha (
Withania somnifera), known for its adaptogenic properties and rich in withanolides, alkaloids, steroidal lactones, tannins, flavonoids and amino acids, reduces stress and anxiety, thereby indirectly supporting potency and reproductive health
(Paul et al., 2021). It also holds promise for improving growth performance in livestock under stall-fed conditions
(Singla et al., 2017). Shatavari (
Asparagus racemosus), rich in saponins, polysaccharides, flavonoids, alkaloids, vitamins and minerals, is recognized for improving female reproductive health by addressing hormonal imbalance, follicular growth, oocyte quality and infertility through reduced oxidative stress and increased antioxidant levels
(Pandey et al., 2018). Additionally, supplementation with shatavari root powder has been shown to significantly enhance milk production in crossbred cows
(Chavan et al., 2023).
Vidhara (
Argyreia speciosa), with alkaloids, steroidal saponins, flavonoids, tannins and resins, promotes sexual health in both sexes
(Riaz et al., 2010). Bidarikand (
Ipomoea digitata), rich in steroidal saponins, flavonoids, alkaloids, tannins and resins, is an effective promoter of spermatogenesis, especially when consumed with milk, demonstrating faster action (
Dutta and Sengupta, 2018). Gokhru (
Tribulus terrestris), containing saponins, alkaloids, flavonoids, steroids and resins, has been found to improve sperm parameters when taken orally
(Sanagoo et al., 2019). Sahajan (
Moringa oleifera), with vitamins, minerals, essential amino acids, antioxidants and fatty acids, enhances antioxidant capacity, maintains semen functionality and reduces sperm abnormalities
(Zeng et al., 2019; Shokry et al., 2020).
Our research focused on the combined effects of these herbs, revealing positive results and affirming their potential synergy and effectiveness. This pioneering study contributes to the growing body of knowledge on herbal supplementation and underscores the importance of exploring synergistic effects for enhanced reproductive well-being in breeding bulls. Previous studies have highlighted the potential of herbal medicines to enhance semen quality in humans and reproductive parameters in breeding boars
(Tu et al., 2023) and roosters
(Qi et al., 2019). Our study stands as the first exploration of utilizing a combination of Ayurvedic herbs in breeding bulls with the effects of these herbs on hormonal dynamics and semen quality.
