Testicular dysfunction is responsible for low sperm quality in Belgian Blue bulls

Stiffness estimated by strain elastography reflects canine testicular spermatogenesis and histology

Ultrasound elastography was proposed for the evaluation of testicular focal lesions, but no studies verified the agreement between the whole histological architecture of the testis and the stiffness measured by elastography. The present study explored the use of strain elastography in the evaluation of testis with normal or abnormal spermatogenesis, classified based on epididymal sperm attributes, and the consistency between elastographic parameters and the testicular histological feature. Strain elastography was performed during the routine andrological examination in 22 dogs presented for elective orchiectomy. Epididymal sperm attributes and testicular histology were analyzed after orchiectomy. Based on the epididymal sperm characteristics, testes were classified according to normal or abnormal spermatogenesis, and strain elastographic attributes were compared between groups. Possible correlations between strain elastography and histological features were also explored. Consistent with the literature in humans, testes with abnormal spermatogenesis were stiffer (mean strain elastographic index 3.6 ± 0.6) compared with normal testes (mean strain elastographic index 1.9 ± 0.2; P < 0.01). The strain elastographic index was negatively correlated with the area occupied by seminiferous tubules (Pearson's rho = -0.716; P = 0.0003), the mean diameter (Pearson's rho = -0.742; P = 0.0002), and thickness of the seminiferous tubule (Pearson's rho = -0.728; P = 0.0002). Surprisingly, no correlations were found between the area occupied by connective tissue in histological sections and elastographic attributes, suggesting that the increased stiffness was not related to the increased amount of connective tissue. This study demonstrated that strain elastography could be used to support the andrological examination, but measurements should be acquired in specific regions to be reliable.

Distribution of extracellular matrix related proteins in normal and cryptorchid ziwuling black goat testes

The Ziwuling black goat is an indigenously in China, their offspring are frequently affected by congenital cryptorchidism. The extracellular matrix (ECM) contains cytokines and growth factors that regulate the development of the testis, and component changes often result in pathological changes. Cryptorchidism is closely related to structural changes in ECM. In this study, the histochemical staining, immunohistochemical, immunofluorescence and Western blot combined with semi-quantitative analysis was used to describe the distribution of the important ECM components Collagen type IV (Col IV), laminin (LN)and heparan sulfate proteoglycans (HSPG) in the normal and cryptorchid testes of Ziwuling black goats. Results showed that: The histochemical staining showed that the dysplasia of seminiferous tubules and decreased number of Sertoli cells in cryptorchidism, as well as sparse collagen fiber. Meanwhile, the distribution of reticular fibers is relatively rich. Furthermore, the PAS and AB staining in the interstitial vessels and lamina propria of seminiferous tubules is weak. The immunohistochemical and immunofluorescence revealed that Col IV, LN was strongly expressed in Leydig, Sertoli cells of normal testes and moderately positive in the spermatogonia and spermatids, but HSPG was not expressed in the spermatogonia. However, cryptorchidism, the expression of Col IV, LN and HPSG in Leydig, Sertoli cells significantly decreased, as well as the expression of Col IV and LN in capillary endothelial cells, but HSPG was moderately expressed in spermatogonia. Based on these data, the underdevelopment of spermatogenic epithelium, decreased synthesis function of collagen fibers and Leydig cells develop usually in the cryptorchidism were shown to be closely related to the abnormal metabolism of Col IV and LN. The positive expressed of HSPG in the spermatogonia of cryptorchid testes is related to the compensatory development of spermatogonia.

Environmental temperature and relative humidity differently affect the sperm characteristics in Brown Swiss and Belgian Blue bulls

In a temperature-increasing scenario, due to global warming, the individual thermic resilience of the male assumes a crucial role in the reproductive efficiency of a male since the thermic stress, such as the inability of the male to reduce body or regional temperature on a physiological level, impairs testicular function. In this study, the effect of the environmental conditions on the fresh semen quality, in terms of volume, concentration, total sperm in the ejaculate, total motility, normal morphology, membrane integrity, and discarding rate, were compared longitudinally in Belgian Blue (BB) and Brown Swiss (BS) bulls. The environmental conditions, summarized in the mean temperature-humidity index (THI), were calculated on the day of collection, as well as 7 days (epididymal maturation), 35 days (late spermatogenesis), and 70 days (early spermatogenesis) before the collection, to reflect spermatogenesis time. Our findings showed that limited seasonal effects were present in the semen quality of BS bulls. On the other hand, in BB bulls lower semen quality was found between July and November, with a different timing depending on the seminal parameter. This effect of the season on BB semen parameters appears to be related to the THI. The data presented in this study shows that the temperature and humidity, summarized in THI, could affect the semen quality of the bull on breed basis, given that volume, concentration, total sperm in the ejaculate, total motility, membrane integrity, and sperm normal morphology were significantly reduced by an increasing THI in the Belgian Blue bulls, but not in Brown Swiss bulls.

Pulse-wave Doppler pulsatility and resistive indexes of the testicular artery increase in canine testis with abnormal spermatogenesis

Pulse-wave Doppler (PWD) ultrasonography of the testicular artery was recently used to compare parameters in fertile and infertile males, or males with normal and abnormal semen quality, while no studies verified the concomitant histological feature of the testis. The experimental hypothesis of the present study was that the blood flow parameters measured by PWD at different levels of the testicular artery reflect sperm attributes evaluated on spermatozoa collected from the tail of the epididymis and testicular histological characteristics. Pulse-wave Doppler parameters were recorded on both testes from 16 dogs of unknown fertility. After routine castration, epididymal spermatozoa were collected and evaluated for sperm total and progressive motility, membrane integrity, and sperm morphology. Testes were submitted to histological and immunohistochemical evaluations to quantify microscopic attributes and connective tissue and vascular area extent, respectively. The findings showed that the increased PWD indexes were suggestive of testicular histological alteration since negative correlations were found between pulsatility index and resistive index, measured in the marginal testicular artery, and histological attributes such as the seminiferous epithelial thickness (R = -0.528, P = 0.016 and R = -0.554, P = 0.005, respectively) and the tubular area/total area ratio (R = -0.494, P = 0.024 and R = -0.563, P = 0.004, respectively). Some histological characteristics, such as tubular diameter, seminiferous epithelium thickness, and the tubular area/total area ratio of the testis are correlated with the percentage of primary abnormalities (R = -0.874, P = 0.001, and R = -0.847, P = 0.001, and R = - 0.865, P = 0.001, respectively). In testes with increased sperm primary abnormalities, higher pulsatility index was found compared with testes with normal spermatogenesis in supratesticular artery (1.07 ± 0.06 vs 0.82 ± 0.23, P < 0.05), marginal artery (0.73 ± 0.04 vs 0.61 ± 0.07, P < 0.05), and intratesticular artery (0.67 ± 0.03 vs 0.43 ± 0.1, P < 0.05). Similarly, the resistive index was found significantly higher in the same vessel tracts in testes with abnormal and normal spermatogenesis (0.62 ± 0.02, 0.53 ± 0.02, and 0.46 ± 0.02 vs 0.51 ± 0.06, 0.44 ± 0.04, and 0.32 ± 0.06, respectively; P < 0.05). Our data demonstrated for the first time the relationship between PWD indexes and the contextual testicular architecture, suggesting that the pulsatility and resistive indexes could be an effective tool in andrology. In light of different histological alterations in the testis, caution is warranted in the definition of thresholds for normal and abnormal testicular blood flow indexes.

Practical methods to assess the effects of heat stress on the quality of frozen-thawed Belgian Blue semen in field conditions

The increased exportation of semen and embryos of double-muscled beef breeds to tropical and developing countries makes it important to investigate the reproductive capacity of these breeds in adapting to tropical conditions. The aim of this study was to evaluate the quality of Belgian Blue semen collected after there is heat-stress (HS; as a mimic of tropical condition) compared with non-heat stressed (NHS; as their comfort zone), using practical spermatozoa staining methods such that prevail in developing countries. There was screening of semen kinetics using CASA and evaluation of their DNA-, acrosome, plasma membrane-integrity, and mitochondrial activity. For each staining technique, there was evaluation of 12 frozen-thawed semen samples from six Belgian Blue bulls collected after there were HS and NHS conditions in Belgium. Mixed linear regression models were used to assess the effects of HS for each CASA variable and staining method outcome using the replicate nested with bull as a random effect. There were differences (P < 0.05) in values when there were semen collections following HS and NHS conditions for several post-thawing kinetic variables. Furthermore, the mean percentages of DNA-, acrosome-, and plasma membrane-integrity, as well as mitochondrial activity were greater (P < 0.05) when semen was collected following NHS compared with HS conditions. Conclusively, results indicated that when there was collection of semen following HS conditions, there were detrimental effects on the viability and quality of Belgian Blue semen which is an important consideration for the semen collection, processing, and evaluation in tropical countries.

Boar management and semen handling factors affect the quality of boar extended semen

Artificial insemination (AI) is the preferred method for reproduction in the majority of the intensive pig production systems Worldwide. To this end, fresh extended ready-to-use semen doses are either purchased from AI-centres or produced by boars kept on-farm. For profitable semen production, it is necessary to obtain a maximum amount of high quality semen from each boar. This paper reviews current knowledge on factors that may affect semen quality by influencing the boar or the semen during processing. Genetic markers could be used for early detection of boars with the highest fertility potential. Genetic selection for fast growth might jeopardize semen quality. Early detection of boars no longer fit for semen production might be possible by ultrasonography of the testes. Seasonal variation in sperm quality could be associated with changes in photoperiod and heat stress during summer. Comfortable housing, with appropiate bedding material to avoid locomotion problems is essential. In some areas, cooling systems may be necessary to avoid heat stress. The sperm quality can be manipulated by feeding strategies aiming, for instance, to increase sperm resistance to oxidative stress and extend storage duration. High collection frequency will negatively influence sperm quality. Also, if collection is not hygienically performed it will result in bacterial contamination of the semen doses. The concern over bacterial contamination has risen not only because of its negative effect on semen quality but also due to the detection of antimicrobial resistance in isolates from extended semen. Moreover, bacterial and viral pathogens must be monitored because they affect semen production and quality and constitute a risk of herd infection. During processing, boar sperm are submitted to many stress factors that can cause oxidative stress and capacitation-like changes potentially reducing their fertility potential. Dilution rate or dilution temperature affects the quality of the semen doses. Some packaging might preserve semen better than others and some plastic components might be toxic for sperm. Standard operation procedures and quality assurance systems in AI centres are needed.

Successful use of a gonadotropin-releasing hormone (GnRH) analog for the treatment of tertiary hypogonadism (GnRH deficiency) in a 5-year-old Belgian Blue bull

A bull was referred for a progressive oligoasthenotheratozoospermia that resulted in a unsuitable seminal quality for the cryopreservation. Breeding soundness evaluation results suggested gonadal dysfunction. Because of the lack of normal ranges for these hormones in the bull, in this study, the hypogonadism and the site of the dysfunction (hypothalamus) were diagnosed by the gonadotropin-releasing hormone (GnRH) stimulation test. The evaluation of pituitary and testicular responsiveness by a GnRH stimulating test revealed a responsiveness of the pituitary and testis, thus a secondary hypogonadism (hypothalamic hypogonadism) was postulated and a therapeutic approach based on the subcutaneous administration of GnRH analog was attempted. An increase in semen volume, concentration and sperm characteristics were detected 9 weeks after the start of the treatment, corroborating the hypothalamic origin of the disease and the useful of the GnRH therapy.

Scrotal insulation and its relationship to abnormal morphology, chromatin protamination and nuclear shape of spermatozoa in Holstein-Friesian and Belgian Blue bulls

The objectives of this study were to identify the stages of spermatogenesis susceptible to elevated testicular temperature in terms of sperm motility, viability, morphology, chromatin protamination and nuclear shape. The latter two valuable parameters are not included in routine semen analysis. Scrotal insulation (SI) was applied for 48 h in 2 Holstein-Friesian (HF) and 2 Belgian Blue (BB) bulls and semen was collected at 7 d intervals along with semen collection of a non-insulated bull of each breed. Semen samples were frozen and assigned to 4 groups: period 1 (preinsulation) = -7 d and 0 d, where 0 d = initiation of SI after semen collection; period 2 = 7 d (sperm presumed in the epididymis during SI); period 3 = 14 d to 42 d (cells presumed at spermiogenesis and meiosis stages during SI); period 4 = 49 d to 63 d (cells presumed at spermatocytogenesis stage during SI). The percentages of progressively motile and viable spermatozoa as assessed by computer-assisted sperm analysis (CASA) and fluorescence microscopy, respectively were decreased whereas abnormal sperm heads, nuclear vacuoles and tail defects were increased at period 3 (P < 0.05) compared to period 1, 2 or 4 in SI bulls of both HF and BB breeds. Protamine deficient spermatozoa as observed by chromomycin A(3) (CMA(3)) staining were more present (P < 0.05) at period 2 and 3 in both breeds compared to period 1 or 4. Sperm nuclear shape as determined by Fourier harmonic amplitude (FHA) was most affected by heat stress during period 3 (P < 0.01) and a higher response was observed in BB bulls than HF bulls. In conclusion, sperm cells at the spermiogenic and meiotic stages of development are more susceptible to heat stress. The lack of chromatin protamination is the most pertinent result of heat stress, together with subtle changes in sperm head shape, which can be detected by FHA but not by conventional semen analysis.