Prospective ultrasonographic and endocrine predictors of spermatogenic onset in ram lambs

Ultrasonography of Testicular Maturation and Correlation with Body Growth and Semen Evaluation in Beagle Dog Model

This prospective study investigated the ultrasonographic appearance of the canine testis from birth to adulthood. Eight purpose-bred laboratory Beagle-breed dogs were monitored from 4 to 40 weeks of life. The following parameters were evaluated every two weeks: bodyweight and height, scrotal and testicular volume, ultrasonographically measured testicular volume, echogenicity, heterogeneity, blood-flow score, ratio of the grayscale intensity value of the testis to the capsule, ejaculate volume, motility, viability, and number of spermatozoa. A correlation analysis was carried out between the various measurements obtained. Fertility was achieved in the 36th week of life. The echogenicity of the testicular parenchyma increased with age, and subsequently to the 30th week of life remained constant. The heterogeneity of the testicular parenchyma, as was evaluated by the standard deviation of the values of grayscale intensity of the parenchyma, also increased with age and was >19 at the onset of fertility. The ratio of grayscale intensity of testicular parenchyma had values < 200 at maturity. A colour Doppler evaluation first detected blood flow in the testis in the 22nd week. After the 32nd week, distinct signals were visible. In the 36th week, >80% of the testes imaged had visible vessels. A significant correlation was found between all the evaluation methods. The findings of the study may help clinicians detect the onset of fertility in dogs, especially when semen evaluation is not feasible; however, their applicability in all breeds or individuals might possibly vary due to genetic, physiological, and developmental differences. In summary, the study ultrasonographically explores the testicular maturity in dogs, with the aim to improve clinical assessments and health management in these animals.

Application of ultrasound technique to evaluate the testicular function and its correlation to the sperm quality after different collection frequency in rams

The frequency of semen collection is a crucial factor to consider in the rams performance inside breeding centers workout. To evaluate this factor, ram Breeding Soundness Evaluation could include sperm quality evaluation and new predictive and non-invasive tools such as ultrasound technique. In this work, an advanced ultrasonography technology, analyzing the testicular volume, echotexture, and vascular function, was used in three different frequencies of semen collection (abstinence frequency, AF; standard frequency, SF; and intensive frequency, IF). Semen samples were cooled (15°C, 6 h) and evaluated in terms of production, motility, viability, apoptosis, and content of reactive oxygen species. Correlation coefficients were calculated between ultrasonography measurements of echotexture and blood flow and sperm quality parameters. Our results showed an increase in the testicular echotexture when the frequency of semen collection was intensified. Doppler parameters (PSV, RI, PI, TABF) increased (P ≤ 0.05) when the frequency of semen collection was intensified. The sperm motility and functionality decreased in the samples of IF (P ≤ 0.05), evidencing the frequency of semen collection's influence. Moreover, moderate positive correlations were established among echotexture and different Doppler parameters with motility parameters in SF. Furthermore, the influence of abstinence days on AI success was analyzed in a field assay. The highest fertility rates were obtained when males had two to five abstinence days. To conclude, frequency of semen collection could be influenced in terms of semen quantity and sperm quality, showing changes in parenchyma echotexture and testicular vascularization. The standard semen collection frequency was the most adequate option. In addition, ultrasonography may be a predictive tool for estimating variations in the sperm quality of donor rams subjected to different frequencies of semen collection in reproduction centers.

Testicular Ultrasound Analysis as a Predictive Tool of Ram Sperm Quality

Simple Summary

In animal production, the prediction of male fertility is vital for the success of specific techniques such as artificial insemination. Thus, testicular ultrasound, a non-invasive diagnostic procedure, could be a useful tool. Moreover, recent ultrasound-video analysis and software developments allow the visualization of tissue at the microscopic level. The objective of this work was to establish a possible correlation between testicular ultrasonography and semen quality in rams. For this purpose, the testicles of nine rams were evaluated and the semen was analyzed for one year. The results revealed that the number of white and grey pixels correlated with sperm parameters indicating poor seminal quality. On the other hand, the increase in the seminiferous-tubule density or the lumen area of these tubules was related to a rise in seminal quality. Therefore, ultrasound-video analysis could be a good tool for evaluating the fertility of rams, either for artificial insemination or on the farm.

Abstract

Testicular ultrasound is a non-invasive technique that could be very useful for predicting ram seminal quality. Recent software developments allow macroscopic and microscopic evaluation of testicular parenchyma. Thus, the aim of this study was to evaluate the testicular echotexture using ultrasound-video analysis and investigate its possible correlation with semen quality. Nine rams were evaluated for one year using a portable ultrasound scanner and the echotexture was analyzed with ECOTEXT^® software. The number of black (Ec1), white (Ec2), and grey pixels (Ec3), tubular density (TD), lumen area (LA), and lumen diameter (LD) were analyzed. Semen was collected by an artificial vagina the same day and the sperm concentration, morphology, motility, viability, phosphatidylserine (PS) translocation, reactive-oxygen-species (ROS) levels, DNA damage and capacitation state were evaluated. Ec2 and Ec3 correlated positively with “bad quality” sperm parameters (the percentage of spermatozoa with high ROS levels, with PS translocation and proximal cytoplasmic droplets), and negatively with motility. In contrast, TD and LA showed a positive correlation with “good quality” parameters (motility or normal morphology) and a negative correlation with spermatozoa with high ROS levels, with DNA fragmentation, and proximal or distal cytoplasmic droplets. Thus, echotexture analysis by ultrasound-video analysis could be a valuable tool for assessing ram fertility.

Testicular quantitative ultrasound: A noninvasive monitoring method for evaluating spermatogenic function in busulfan-induced testicular injury mouse models

Busulfan-induced testicular injury mouse models are commonly used for experiments on spermatogonial stem cell transplantation, treatments for azoospermia due to spermatogenic failure and preserving male fertility after chemotherapy. Here, we investigated the value of testicular quantitative ultrasound for evaluating spermatogenic function in this model. In this study, testicular ultrasound was performed on mice from day 0 to 126 after busulfan treatment (n = 48), and quantitative data, including the testicular volume, mean pixel intensity and pixel uniformity, were analysed. The results revealed that from day 0 to 36, the testicular volume was positively associated with the testicle-to-body weight ratio (r = .92). On day 63, the pixel uniformity, which remained stable from day 0 to 36, declined significantly compared with that on day 36 (p < .01). On day 126, when the whole progression of spermatogenesis could be observed in most tubules, the mean pixel intensity also returned to normal (p > .05). In conclusion, testicular quantitative ultrasound could be used as a noninvasive and accurate monitoring method for evaluating spermatogenic function in busulfan-induced testicular injury mouse models.

Feline testicular ultrasonogram differentiates pre vs. postpubertal and normal vs. disrupted spermatogenesis

The aims of this study were: to ultrasonograhically describe and compare testicular parenchyma echogenicity and heterogeneity using digital image analysis in: I) prepubertal (PREP), peripubertal (PERI) and mature (MAT) cats; II) Normal and abnormal mature felids. Secondary, the relationships between histomorphological and ultrasonographic attributes of the testes were also determined. I) Fourteen, PREP, PERI and MAT male cats were ultrasonographically examined and then castrated. II) Seven adult cats were ultrasonographically examined before and after a GnRH antagonist administration and then castrated. All the testes were grossly and histomorphometrically assessed. In the frozen digital images of the longitudinal ultrasound sections, 3 regions of interest (ROI, 1 mm2) were selected. Within each ROI the echogenicity and the heterogeneity of the testicular parenchyma were digitally analyzed. In experiment I, testicular volume (0.15 ± 0.0 vs. 0.49 ± 0.1 vs. 1.65 ± 0.1; P < 0.01) and gonadosomatic index (0.04 ± 0.0 vs. 0.05 ± 0.0 vs. 0.08 ± 0.0; P < 0.01), echogenicity (56.54 ± 0.75 vs. 81.87 ± 5.88 vs.94.67 ± 3.62; P < 0.01) and heterogeneity (10.2420 ± 1.3740 vs.13.65 ± 0.65 vs. 14.67 ± 1.49; P < 0.01) augmented throughout PRE, PERI, and MAT. In experiment II, testicular volume (1.00 ± 0.09 vs. 0.85 ± 0.09; P < 0.05), echogenicity (87.74 ± 1.53 vs. 83.32 ± 1.54; P 0.01) but not heterogeneity (14.09 ± 0.26 vs. 14.19 ± 0.29; P > 0.05) decreased in the post GnRH antagonist abnormal testes. For both experiments, testicular volume, seminiferous tubular diameter, percentage of spermatids as the most mature cell type, and luminal/intertubular ratio were highly correlated (P < 0.01) with their echotextural attributes. Computer-assisted image analysis of B mode ultrasonogram appears as a good indicator of pubertal development and mild alterations of spermatogenesis in felids.

Changes in testicular size, echotexture, and arterial blood flow associated with the attainment of puberty in Dorper rams raised in a subtropical climate

There is a paucity of information on the relationships of testicular morphology, echotextural attributes, and blood flow dynamics with pubertal development of rams raised in a subtropical climate. Forty-five Dorper rams (24 rams aged 8-11 months and 21 rams aged 12-24 months) were examined using a portable ultrasound scanner connected to a 7.5-MHz transducer. Computer-assisted analyses of testicular ultrasonograms utilized commercially available Image ProPlus^® analytical software. Spectral Doppler scans of testicular arteries were performed immediately after scrotal (B-mode) ultrasonography to determine peak systolic velocity (PSV), end-diastolic velocity (EDV), resistive index (RI = [PSV-EDV]/PSV), and pulsatility index (PI = [SPV-EDV]/mean velocity) of the blood vessels. The length of the testes (9.7 ± 0.3 compared with 9.0 ± 0.2 cm) and scrotal circumference (33.3 ± 0.5 compared with 31.8 ± 0.4 cm) were greater (p < 0.05) but testicular depth (4.5 ± 0.1  compared with 4.9 ± 0.08 cm) was less (p < 0.05) in sexually mature compared with peripubertal rams. [Corrections added on 9 Jan 2019 after initial online publication: The testicular size values in the sentence were corrected.] There were no differences (p > 0.05) between the two age groups of Dorper rams in blood flow indices of testicular arteries. Mean numerical pixel values (100.5 ± 4.1 compared with 89.2 ± 4.8) and pixel heterogeneity (25.6 ± 0.6 compared with 23.6 ± 0.5) of testicular parenchyma were greater (p < 0.05) in peripubertal than in postpubertal rams. Semen volume was negatively correlated with PI of testicular arteries (r = -0.57, p = 0.04). In summary, the attainment of sexual maturity in the rams of the present study was associated with significant changes in testicular length and depth, scrotal circumference, and parenchymal echogenicity/hetrogeneity but not in testicular volume and blood perfusion rates. Testicular artery PI can be used to predict the volume of ejaculate in rams.