Spatial local expressions of kisspeptin in the uterus and uterine tubes and its relationship to the reproductive potential in goats.

Kisspeptins are neuropeptides encoded by the Kiss1 gene that was discovered as a metastasis suppressor gene in melanoma and breast cancer. Kisspeptin has pivotal functions for gonadotropin-releasing hormone secretion and plays integrated roles in the hypothalamic-pituitary-gonadal axis. However, little is known about the peripheral expression of kisspeptin in ruminants, especially in the female reproductive tract. Here, the objectives of the current study were to investigate the spatial localization of kisspeptin and mRNA expression of Kiss1 and its receptor (Kiss1r) in the fallopian tubes (FT) and uterus of goats at varied reproductive activity (cyclic versus true anoestrous goats, n=6, each). Specimens of the uterus and FT were collected and fixed using paraformaldehyde to investigate the localizations of kisspeptin in the selected tissues by immunohistochemistry. Another set of samples was snape-frozen to identify the expressions of mRNAs encoding Kiss1 and Kiss1r using real-time PCR. Results revealed immunolocalizations of kisspeptin in the uterus and the FT. The staining of kisspeptin was found mainly in the mucosal epithelium of the uterus the FT, and the endometrial glands. Very intense staining of kisspeptin was found in the uterine and FT specimens in the true anoestrous goats compared to that in cyclic ones. The expression of mRNA encoding Kiss1 gene was significantly higher in the uterine specimen of cyclic goats (1.00±0.09) compared to that in the true anoestrous goats (0.62±0.08) (P ˂0.05), while the expression of mRNA encoding Kiss1r was significantly (P ˂0.001) higher in the uterine tissues of true anoestrous goats (1.78±0.17) compared to that in cyclic ones (1.00±0.11). In conclusion, immunohistochemical localization of kisspeptin and the expression of mRNA encoding Kiss1/Kiss1r revealed spatial changes in the uterus and FT of goats according to the reproductive potential of goats (cyclic versus true anoestrous goats). However, the definitive local role of kisspeptin in the uterus and FT need further investigation.

Effect of pre-treatment of melatonin on superovulation response, circulatory hormones, and miRNAs in goats during environmental heat stress conditions.

Environmental heat stress has a deleterious impact on farm animal reproductive performance. The purpose of this study was to see how the addition of melatonin affected the efficacy of the superovulation regimen in goats in hot climatic conditions. Sixteen Shiba goats were synchronized and divided into two equal groups (n = 8, each): the melatonin group, which received a single S/C dose of melatonin, and a control group, treated with one ml of corn oil only. Ultrasonographic assessment of ovarian structures (Graafian follicles; GFs and corpus lutea; CLs) morphometry and hemodynamics were performed during the estrous phase of the superovulation (D0) and at day7 after ovulation (D7) of the superovulation regimen. The peripheral reproductive hormones were measured, and microRNAs were characterized. The mean diameter and the total-colored area of GFs during the D0 were significantly (P˂0.05) higher in the melatonin group (5.42 ± 0.11 mm and 1592.20 ± 45.26 pixels, respectively) compared to the control group (4.62 ± 0.12 mm and 1052.55 ± 29.47 pixels, respectively). Concentrations of LH and E2 increased significantly (P˂0.05) in the melatonin group (1.06 ± 0.06 ng/ml and 46.34 ± 2.77 pg/ml, respectively) compared to the control group (0.75 ± 0.12 ng/ml and 29.33 ± 1.89 pg/ml, respectively). At D7, the melatonin-received goats attained greater values in the mean count (6.75 ± 0.33, P˂0.005), diameters (6.08 ± 0.12 mm, P˂0.01), and total-colored area (17137.30 ± 128.53 pixels, P˂0.01) of detected CLs and progesterone concentrations (4.08 ± 0.24 ng/ml) compared to control goats (4.00 ± 0.28, 4.50 ± 0.19 mm, 11156.87 ± 117.90 pixels, and 2.90 ± 0.18 ng/ml respectively). MiRNA expression analysis was identified during both stages denoting several up and downregulated miRNA candidates among the studied groups. In conclusion, incorporating melatonin enhanced the efficiency of the superovulation regimen in goats under hot climatic conditions.

Effect of Acute Melatonin Injection on Metabolomic and Testicular Artery Hemodynamic Changes and Circulating Hormones in Shiba Goats under Sub-Tropical Environmental Conditions.

The beneficial effects of melatonin were investigated to mitigate various detrimental effects and toxicity on reproductive performance. The present study aimed, for the first time, to explore the effect of intravenous melatonin injection on testicular artery hemodynamics (TH) and metabolomic changes, reproductive hormones in heat-stressed bucks. Ten bucks were randomly split into two groups (five each): (1) the melatonin group, treated with a single intravenous dose of melatonin solution containing 10 mg melatonin each, and (2) the control group, which was treated with 10 mL of the vehicle without melatonin. Changes in the TH at the level of the supra testicular artery (STA) were assessed by triplex ultrasonography just before (0 h) and at 0.5, 2, 7, 24, and 168 h after melatonin or vehicle administration. Doppler velocity parameters of peak systolic velocity (PSV; cm/s), end-diastolic velocity (EDV; cm/s), and time average maximum velocity (TAMAX; cm/s) were measured. Doppler indices (resistive index; RI and pulsatility index; PI), systole/diastole (S/D) ratio and total arterial blood flow volume (TABFV; ml/minute) were measured. Peripheral concentrations of FSH, LH, inhibin, melatonin, testosterone (T), estradiol (E2), and cortisol were measured just before injection (0 h) and at 0.5, 2, 7, and 24 h and daily up to day 7 post administration in both groups. Results revealed reductions in the RI values and increases in the TABFV in the melatonin group compared to the control one, especially 2 h after administration. Significant increases in concentrations of FSH, T, E2, and melatonin and decreases in cortisol and inhibin in the melatonin group compared to the control one. Plasma metabolomic analysis at 2 h indicated the up-regulation of L-glutamine, L-arginine, sorbitol, D-glucose, ascorbic acid, and ornithine and the down-regulation of D-xylose, D-arabitol, ribitol, and oleic acid in the melatonin versus the control group. In conclusion, acute administration of melatonin (10 mg IV) enhanced testicular artery blood flow and plasma reproductive hormones in the Shiba goat under heat-stress circumstances.

Effect of xylazine sedation on testicular blood flow, testicular echotexture, and circulating hormones in Shiba goats.

Under field conditions, sedation may be required for a full assessment of the reproductive potential of farm animals. The present study aimed to investigate the effect of xylazine sedation on testicular hemodynamics (TBF), echotexture, testicular volume (TV), and circulating hormones in goats. Sixteen male Shiba goats were sedated using the recommended dose of xylazine (0.05 mg/Kg BW). Testicular hemodynamics were evaluated using color-pulsed Doppler ultrasonography before and after sedation. Echotexture of the testicular parenchyma and TV were assessed using computerized image analysis. Concentrations of testosterone, estradiol (E2), inhibin, cortisol, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) were measured using radioimmunoassay. There were no effects of xylazine sedation in TBF, TV, testicular parenchyma parameters, and concentrations of testosterone, inhibin, FSH, and LH (P ˃ 0.05). However, after sedation, there was significantly (P ˂ 0.05) lower cortisol and E2 concentration (42.88 ± 6.79 ng/ml and 2.47 ± 0.58 pg/ml, respectively) than before sedation (94.89 ± 13.74 ng/ml and 8.65 ± 1.79 pg/ml, respectively). The required time to perform the full scanning of the testis was significantly lower (8.50 ± 0.38 min) after xylazine sedation compared to the non-sedated goats (25.75 ± 1.14 min). In conclusion, xylazine sedation may be practically recommended for the evaluation of TBF in goats because it did not significantly alter velocities parameters and Doppler indices of blood flow within the testicular arteries. Most plasma hormones did not significantly change; however, E2 and cortisol were significantly reduced after xylazine administration.

An updated insight on testicular hemodynamics: Environmental, physiological, and technical perspectives in farm and companion animals.

In all organs, control of blood flow is important but might be particularly critical for testicular functions. This is because of the very low oxygen concentration and high metabolic rate of the seminiferous tubules, the physiological temperature of the testis, and its location outside the abdominal cavity. Many factors affect the characteristics of TBF in farm and companion animals, such as environment (thermal and seasonal effects) and physiological (species, breeds, age, body weight, and sexual maturity). Thermal environment stress has detrimental effects on spermatogenesis and consequently has more serious impacts on both human and animal fertility. Numerous studies have been performed to assess TBF in different animal species including bulls, rams, bucks, alpacas, stallions, and dogs with varied results. Hence, assessment of TBF by Doppler ultrasonography is of great importance to estimate the effect of high environment temperature on testicular functions. Also, differences observed in the TBF may result from different technical aspects such as the identification of the segment of the testicular artery to be examined. In the current review, we focused on the imperative roles of TBF in various animal species. Besides, we discussed in detail various factors that could affect TBF. These factors can significantly modify the TBF and thus should be considered when establishing reference values in farm animals for better clinical diagnosis. The information provided in this review is valuable for researchers and veterinarians to help them a better understanding of testicular hemodynamics for the proper evaluation of breeding soundness examination in males.

Diurnal rhythms in testicular blood flow, testicular morphometry and reproductive hormones in Shiba goats.

CONTEXT: Testicular blood flow (TBF) is crucial for testicular function. The pattern of TBF in Shiba goats indicates seasonal variations. AIMS: This study aimed to investigate the effect of diurnal variations on TBF, testis volume (TV), testicular echogenicity, and reproductive hormones in goats over a 24-h period. METHODS: In three trials that went for three consecutive days each, 12 bucks were scanned using Triplex ultrasonography to assess the TV, pixel intensity of testicular echotexture (PIX), and Doppler indices of TBF (resistive index: RI and pulsatility index: PI) in four-time points a day (at 6.00, 12.00, 18.00, and 00.00h). Concomitantly, the changes in circulating FSH, LH, inhibin, testosterone (T), estradiol (E2), cortisol, and melatonin were assessed. KEY RESULTS: Results revealed diurnal alterations in the calculated RI of TBF and the PIX of testicular parenchyma (P <0.05). Lower RI values of the TBF were observed at 6.00h compared to other time points. There were significant diurnal alterations in the levels of FSH (P <0.05), LH (P <0.05), T (P <0.0001), E2 (P <0.0001), cortisol (P <0.0001), and melatonin (P <0.0001). FSH attained a higher concentration at 18.00h compared to 12.00h. Concentrations of LH were significantly higher at 06.00h compared to those at 18.00h. Concentrations of T were significantly higher at 6.00 compared to other time points. E2 showed higher concentrations at 6.00h and 00.00h compared to 12.00h and 18.00h. On the contrary, concentrations of cortisol were significantly higher at 12.00h and 18.00h compared to 06.00h and 00.00h. The highest concentrations of melatonin were observed at 00.00h compared to other time points, while the lowest concentrations were at 12.00h. CONCLUSIONS: Diurnal rhythm induces significant changes in TBF, testicular PIX, and circulating FSH, LH, T, E2, cortisol, and melatonin over the 24-hday. IMPLICATIONS: The outcomes of the study are reflected in the advisability of monitoring the TBF at a fixed time a day to avoid the circadian rhythm effect.

Advances in applications of color Doppler ultrasonography in the andrological assessment of domestic animals: A review.

Compared to human cases, potential applications of Doppler imaging technology in farm animals' practice are still limited and are mostly concerned with females. Testicular blood perfusion (TBP) is the pathway through which all nutrients, oxygen, and regulatory agents pass through to the testis. TBP is crucial to the testis function because of the high metabolic rate and very low concentration of oxygen in the seminiferous tubules, which constitute about 70%-80% of the testicular mass. Color Doppler ultrasonography is one of the recent non-invasive technologies, which plays a vital role in the assessment of blood flow to the testis in various animal species. In the past 20 years, a significant number of studies have highlighted the importance of assessments of TBP using color Doppler ultrasonography to illustrate its potential uses for breeding soundness examination, diagnosis, and monitoring of infertility problems in farm animals. This review was aimed at providing, for the first time, updated knowledge on the potential clinical uses of color Doppler ultrasonography for the assessment of TBP in domestic animals. Additionally, a few essential details on the relationship between TBP and male fertility are discussed in this review. Furthermore, a number of caveats relating to the use of color Doppler ultrasonography are discussed, which collectively appear to constrain its routine, on-farm application for breeding soundness assessments, at least at the present. The new perspectives related to animal reproduction that researchers claim to do in further investigations are also discussed.

Assessment of correlations and concentrations of salivary and plasma steroids, testicular morphometry, and semen quality in different climatic conditions in goats.

The current study aimed to investigate whether steroids (testosterone, estradiol, and cortisol) in the saliva of goats reflects their concentrations in the plasma. Also, it aimed at ascertaining, for the first time, the effect of changes in climatic conditions (spring versus summer) on the aforementioned steroids, testicular volume, testicular echotexture (pixel intensity; PI, and integrated density; ID), and semen quality in goats. Saliva and plasma samples were collected from 7 male Shiba goats weekly in spring and summer for measurement of testosterone (T; ng/ml), estradiol (E2; pg/ml), and cortisol (ng/ml) using radioimmunoassay. The changes in testicular volumes (TV/ml) and echogenicity were monitored weekly using ultrasonographic assessments concomitantly with subjective evaluations of semen parameters. Results revealed a highly significant positive correlation (r = 0.72; P < 0.0001) between plasma and salivary cortisol. Mild significant positive correlation was found between salivary and plasma T levels (r = 0.31; P < 0.002). However, low non-significant negative correlation was reported between salivary and plasma E2 levels (r = -0.24; P > 0.05). Higher levels of salivary cortisol were found in summer than in the spring (3.8 ± 0.6 ng/ml versus 1.4 ± 0.3 ng/ml; P < 0.001). However, no differences in levels of T, E2, and plasma cortisol were recorded between spring and summer (P > 0.05). Values of testicular PI and ID were significantly (P < 0.001) higher in the summer (94.5 ± 4.9, 258,388 ± 13,190, respectively) than in the spring (74.0 ± 2.1, 200,922 ± 5704, respectively). Meanwhile, TV and semen parameters did not significantly differ between spring and summer. In conclusion, saliva can be considered as an alternative biological fluid for the measurement of cortisol and T, but not suitable for E2. Climatic conditions significantly impact the levels of cortisol in saliva and testicular echogenicity in goats.