Effects of letrozole administration on growth and reproductive performance in Markhoz goat bucklings

Dietary Nannochloropsis oculata ameliorates lead acetate induced reproductive toxicity in Barki rams: NF-κB and cytokines pathways

The study aimed to explore the protective effect of Nannochloropsis oculata (N.oculata) on lead induced reproductive toxicity in rams. Sixteen Barki rams were divided equally in to 4 groups; group A: control, group B: was administered 3 % dietary N. oculate, group C: was gavaged 5 mg/kg/day lead acetate and group D: was supplemented with 3 % dietary N. oculata and gavaged with 5 mg/kg/day lead acetate. The experiment lasted 180 days. Semen and blood samples were obtained. Ejaculates were examined for semen criteria besides, analysis of testosterone. Testicular oxidant/antioxidant markers, cytokines, gene expression of interleukin-6 (IL-6) and nuclear factor Kappa B (NF-κB) were estimated. Alga-treated rams revealed significant upgrades in semen criteria, serum testosterone and reduced glutathione (GSH); meanwhile, downregulation in malondialdehyde (MDA), IL-4, IL-2 as well as gene expressions of IL-6 and NF-κB as compared to other treated groups. However, lead-treated rams showed significant deteriorations in semen criteria and reduced GSH while significant elevations in MDA, IL-4, IL-2 as well as gene expression of IL-6 and NF-κB were noticed than control. Alga supplementation to lead-intoxicated rams significantly upgraded the lead induced alterations that were manifested by improvement in testicular histopathology. In conclusion, the addition of alga mitigated lead induced reproductive toxicity in rams via improving testosterone, oxidant/antioxidant status, semen criteria and reducing inflammatory cytokines.

Effect of a single dose of letrozole on ejaculation time, semen quality, and testicular hemodynamics in goat bucks subjected to heat stress

Letrozole (LTZ) is an aromatase inhibitor that limits estrogen (E2) production and increases testosterone (T) levels. This research aimed to examine the impact of a single dose of LTZ on testicular hemodynamics, ejaculation time, and semen quality in goats under heat stress (HS). Therefore, Doppler examination and semen evaluation were performed on twelve mature bucks for two weeks (W-1, W-2) as pre-heat stress control during winter. Then during summer HS bucks were subjected to Doppler examination, semen evaluation, and hormonal analysis (T, E2, and LH) at 0 h. Afterward, bucks were assigned into two groups and subcutaneously injected with physiological saline (n = 6; CON) or LTZ (0.25 mg/kg BW; n = 6; LTZ). Both groups were subjected to Doppler scanning and hormonal analysis at 2, 4, 24, 48, 72, 96,144, and 168 h. Semen evaluation was performed at 48 and 168 h. The LTZ group showed increasing (P < 0.05) in semen volume, sperm motility, and viability and decreasing (P < 0.05) in ejaculation time and sperm abnormalities compared to CON group at 48 h. Additionally, T concentrations increased (P < 0.01) at 2, 24, and 48 h, E2 decreased (P < 0.01) from 2 to 48 h, and LH raised (P < 0.01) at 2 and 72 h in LTZ group compared to CON one. Doppler indices reduced (P < 0.05) at 96 h in LTZ group. semen pH and scrotal circumference were not affected by LTZ. In conclusion, LTZ administration shortened ejaculation time and enhanced semen quality in bucks during HS.

Effects of short-term oral letrozole on fresh semen parameters, endocrine balance, and prostate gland dimensions in domestic dogs

BACKGROUND

Aromatase inhibitors improve male fertility by modifying the hormonal control of spermatogenesis. The present study aimed to investigate the effects of oral administration of letrozole on testosterone and estradiol concentrations and their ratios in blood serum, seminal plasma, prostatic fluid, sperm quality in fresh semen, and prostate gland dimensions. Seven adult male intact mixed-breed dogs were selected. The animals received letrozole (72 µg/kg, PO) daily for four weeks. Blood samplings and semen collections were carried out on days 0 (control), 14 (treatment), 28 (treatment), and 42 (post-treatment).

RESULTS

Our results showed that letrozole administration resulted in a 4.3 fold significant increase in serum, seminal plasma, and prostatic fluid testosterone levels after 14 days. This remained high until the end of the study. Serum and prostatic fluid estradiol levels did not change significantly over the study period. However, the seminal plasma estradiol level showed a significant increase on day 14. The estradiol: testosterone ratio was significantly reduced on day 14 in serum, seminal plasma, and prostatic fluid samples. Letrozole significantly improved the ejaculated spermatozoa viability and concentration after 28 days of oral administration. However, the sperm plasma membrane functional integrity and kinematic parameters were not significantly affected by the treatment. Transabdominal ultrasound examination revealed a significant increase in the height, width, and volume of the prostate gland after 28 days of treatment.

CONCLUSIONS

According to the present research, oral administration of letrozole for 28 days affects local and systemic sex hormone balance leading to an improvement of the ejaculated canine spermatozoa viability and concentration concurrent with an increase in the prostate gland dimensions.

New insight into copy number variations of goat SMAD2 gene and their associations with litter size and semen quality

Copy number variations (CNV) contribute significantly to genetic variations. Numerous studies have shown that CNV affects phenotypic traits in livestock. The SMAD family member 2 (SMAD2) is a leading candidate gene in reproduction and has a crucial effect on litter size. Additionally, SMAD2 is also required for male reproduction and influences male germ cell development. However, there are no reports on investigating the effect of CNVs in the SMAD2 gene on reproductive traits in goat. Therefore, the goal of this study was to explore associations between CNV of the SMAD2 gene and litter size and semen quality in Shaanbei white cashmere (SBWC) goats. In this study, two CNVs within the SMAD2 were identified in 352 SBWC goats (50 males and 302 females). The association analysis revealed that only CNV2 was significantly associated with female goat first-born litter size (P = 3.59 × 10^-4), male semen concentration (P < 0.01), ejaculation volume, live sperm count, and sperm deformity rate (P < 0.05). In terms of phenotypic performance, the individuals with loss genotypes outperformed those with other genotypes. CNV1 and CNV2 genotype combinations containing their dominant genotypes were also associated with goat litter size (P = 1.7 × 10^-5), but no differences in semen quality were found. In summary, CNV2 of the SMAD2 gene is useful for molecular marker-assisted selection breeding, as it is associated with essential goat reproductive traits.

Zinc and Shell Flour as Innovative Natural Aromatase Blocker to Increase Testosterone Concentration

The hormone testosterone is essential in various biological processes, including reproductive function so its presence in the body must remain stable. Low concentrations of testosterone can affect secondary traits and libido in male animals. Testosterone concentrations are usually increased through hormonal induction, but this will harm long-term administration. The alternative offered in this problem is to give aromatase blockers both in the form of commercial drug injection (letrozole) and natural ingredients (shell powder). Aromatase blockers can inhibit the synthesis of estrogen from testosterone at certain doses that are usually different for each animal, administering aromatase blockers has been shown to increase testosterone concentration, in birds and chickens the administration of aromatase blockers did not have any significant side effects.