Bacteria (environmental contaminants and occasionally potential pathogens) are found in most stallion ejaculates and may negatively affect sperm quality during storage. Since the use of antibiotics ...can lead to the development of resistance, an alternative means of microbial control is desirable. The removal of bacteria from stallion semen using Single Layer Centrifugation through Androcoll-E was investigated. Known doses of cultured bacteria were added to freshly collected ejaculates (15mL aliquots) before processing by Single Layer Centrifugation. The resulting sperm pellets and controls (not processed by Single Layer Centrifugation) were cultured and the bacteria identified. In experiment 1, doses of E. coli from 2×102 to 2×107 colony forming units were added to aliquots of semen. In experiment 2, Taylorella equigenitalis or a mix of E. coli, Klebsiella pneumoniae and Streptococcus equi subsp. zooepidemicus (approximately 7×106, 5×106, and 6×106cfu, respectively) were added to 15mL aliquots of semen. In experiment 1, more than 90% of the bacteria were removed where loading doses were >×104cfu/mL. In experiment 2, varying proportions of different bacteria were removed, ranging from 68% for naturally occurring Corynebacterium spp. to >97% for added cultured E. coli. Thus, Single Layer Centrifugation can separate spermatozoa from many, but not all bacteria in stallion ejaculates and could be a useful alternative to adding antibiotics to semen extenders to control bacterial contamination. However, further research is needed to determine the effect of small numbers of bacteria on sperm quality.
Contents
Despite the scale of the livestock breeding industry, where many millions of insemination doses are prepared each year, sperm preparation techniques are used infrequently in animal assisted ...reproduction compared with its human counterpart. However, some of the techniques used for human sperm preparation, for example, density gradient centrifugation, improve the quality of sperm preparations which is, in turn, reflected by an increased conception rate. The preparation technique separates motile spermatozoa with normal morphology and intact DNA from the total sperm population, leaving behind immature or senescent spermatozoa, morphologically abnormal ones and those with damaged DNA. Furthermore, the motile spermatozoa are removed from the seminal plasma which carries cells, cellular debris and reactive oxygen species, as well as pathogens. Gradient‐prepared spermatozoa survive longer, either in liquid storage or when cryopreserved, and are free of bacteria and viral infectivity if prepared carefully. Preparation techniques such as density gradient centrifugation, or the simplified single layer centrifugation technique, have considerable potential for aiding sperm preparation from poor quality semen samples, such as may be obtained from unselected semen donors in captive breeding programmes, or from performance horses. Moreover, the removal of pathogens has important implications, both for disease control and for avoiding the use of antibiotics in semen extenders, which can be detrimental to sperm survival.
•SCSA and SCDt have not been compared yet for dog DNA sperm fragmentation.•Moderate correlation but poor agreement was found between SCSA and SCDt.•Two new morphologies for SCDt were found: receding ...and bald sperm.•SCSA and SCDt are useful for dog epidydimal sperm DNA fragmentation dynamic analysis.
The aim of this study was to compare sperm DNA fragmentation of frozen-thawed epididymal sperm of dogs using the SCSA (Sperm Chromatin Structure Assay) and SCDt (Sperm Chromatin Dispersion test). For this purpose, epididymis from neutered dogs were minced and incubated in a Tris-based extender. The recovered sperm were frozen in a two-step cooling protocol with Tris-based, egg yolk extender and increasing glycerol concentrations, and stored in liquid nitrogen. After thawing, each replica was incubated at 38 °C for 24 h. Sperm DNA fragmentation index (sDFi) was assessed by SCSA and SCDt at 0, 3, 6 and 24 h of incubation and compared within treatments. The relationship and agreement between techniques were evaluated by Pearson’s coefficient and Intraclass Correlation Coefficient (ICC). The results were expressed as mean ± standard error of the mean (SEM). Both techniques indicated there was a significant increase of DNA fragmentation after 24 h of incubation. Moderate correlation (r = 0.65; P<0.01) but lack of agreement (ICC = 0.451; P>0.05) was found between SCSA and SCDt. The lack of agreement indicates that SCSA and SCDt measure different aspects of DNA fragmentation. Four halo morphologies were detected after 24 h of incubation using the SCDt: un-fragmented DNA with a small halo, fragmented DNA with large halo and two new halo presentations never described before for dog sperm: receding sperm with a disappearing halo and “bald” sperm without chromatin dispersion halo around the core. Sperm without a halo of chromatin dispersion are not described by the manufacturer and are similar to un-fragmented sperm, which could lead to erroneous results when using the SCDt. Further studies with different incubation periods and including the new morphologies described in this study should be performed. In conclusion, although SCSA and SCDt can evaluate the changes in the sperm DNA fragmentation dynamics of frozen-thawed epididymal dog sperm, these provided different findings on sperm DNA fragmentation.
The symptom burden resulting from sleep-disordered breathing (SDB) in patients with mild-to-moderate congestive heart failure (CHF) is unclear. The current authors monitored 24-h activity levels and ...compared subjective and objective measures of daytime sleepiness in 39 CHF patients, New York Heart Association class 2-3, on optimal medication. A total of 22 patients were classified as SDB (apnoea/hypopnoea index (AHI) median (range) 22.3 (16.6-100) events.h-1), and 17 as no SDB (NoSDB; AHI 3.7 (0-12.3) events.h-1). SDB was defined as AHI>or=15 events.h-1. Patients were assessed by 24-h activity monitoring (actigraphy) for a period of up to 14 days, a single objective sleepiness test (Oxford Sleep Resistance test) and Epworth Sleepiness Scale. The duration of daytime activity was significantly shorter in the SDB group compared with the NoSDB group. The SDB group also had increased time in bed and poorer sleep quality, as shown by the fragmentation index. Objectively the SDB group when compared with the NoSDB group were significantly sleepier, subjectively the groups did not differ. The amount of napping was similar for both groups. Despite the lack of subjective symptoms of daytime sleepiness, congestive heart failure patients with sleep-disordered breathing were objectively sleepier during the day and had reduced daytime activity with longer periods in bed and poorer sleep quality when compared with those without sleep-disordered breathing.
•The application of assisted reproduction techniques (ART) bypasses some of in vivo sperm selection mechanisms.•The implementation of reproductive biotechnologies is essential to accelerate the ...genetic progress in camelids species.•Androcoll E-Large and Percoll® significantly increased the proportion of llama sperm with progressive motility.•Swim up would not be efficient to recover an adequate number of progressively motile sperm from ejaculated llama semen.
The objective of this study was to compare the efficiency of different sperm selection methods applied to the same llama ejaculate. Four treatments were compared: two variants of the swim up technique (with and without seminal plasma), and two different colloids, Androcoll-E-Large and Percoll®. Using electroejaculation, 21 semen samples were obtained from 7 llama males (n=7, r=3). The ejaculates were incubated in a solution of 0.1% collagenase, to decrease thread formation, and then split into 4 aliquots: one aliquot was layered over a column of Androcoll-E-Large (SLC) and the second over a column of Percoll (45%). The third aliquot was deposited in a tube with culture medium and was incubated at a 45° angle for 30min at 37°C (SU1). The last aliquot was centrifuged to separate the spermatozoa and seminal plasma. The sperm pellet obtained was resuspended, and transferred to a tube with culture medium which was incubated at an angle of 45° for 30min at 37°C (SU2). Both aliquots SLC and P showed higher proportions of progressive motility and plasma membrane functionality (p≤0.05) than raw semen. There were no significant differences (p>0.05) in sperm viability and in normal spermatozoa between raw semen and treatments. Nevertheless, only SLC did not have a significant increase of bent tails. In conclusion SLC centrifugation would be the method of choice for selecting llama spermatozoa.
•Electroejaculated and epididymal red deer sperm were cryopreserved.•On thawing they were prepared by Single Layer Centrifugation (SLC) with Androcoll-S.•Sperm motility was improved in the SLC ...samples compared to controls.•Viability, mitochondrial activity and acrosomal status were improved in SLC samples.•These improvements were maintained for an incubation period of 2h.
Single Layer Centrifugation is a useful technique to select sperm with good quality. The use of selection methods such as Androcoll could become an important tool to improve the quality of sperm samples and therefore to improve other artificial reproductive techniques such as sperm sex sorting, in vitro fertilization or AI. The aim of this study was to evaluate the effect of a Single Layer Centrifugation with Androcoll-S on the sperm quality of red deer sperm samples of two different origins, electroejaculated samples and epididymal samples obtained post-mortem, after thawing and after an incubation for 2h at 37°C. Sperm motility, viability, membrane permeability, mitochondrial activity, acrosomal status and DNA fragmentation were determined for all samples. The samples selected by Androcoll-S showed an improvement in sperm kinematics compared to unselected samples after thawing and after incubation. The same effect was observed in parameters such as viability, mitochondrial activity or acrosomal status which were improved after the selection. In contrast, no difference was found in DNA fragmentation between selected and unselected samples within the same sperm type. We conclude that sperm selection by SLC with Androcoll-S after thawing for red deer sperm of both types is a suitable technique that allows sperm quality in both types of sperm samples to be improved, thereby improving other assisted reproductive techniques. Further studies (IVF and in vivo fertilization) are required to determine whether this improvement can increase fertility, as has been shown for other species.
Summary
The technique of single layer centrifugation through species‐specific colloids has been gaining acceptance over the last few years as a practical method of improving the sperm quality of ...stallion semen for artificial insemination. This article explains the background to the technique and the different colloid formulations used, suggests some applications of the technique with particular reference to the equine breeding industry, describes the method in detail, and finally provides some guidance for problem solving. It is intended as a practical guide for those considering using the technique to improve sperm quality and pregnancy rates in equine artificial insemination and embryo transfer.
There is controversy about whether the presence of some seminal plasma (SP) in an equine insemination dose is necessary for promoting fertility. A new technique for improving stallion sperm quality, ...single layer centrifugation (SLC) using a species-specific colloid, Androcoll-E, selects a sperm subpopulation that is highly motile with normal morphology, intact membranes and good chromatin integrity from the rest of the ejaculate and removes SP. The present study was designed to investigate the effect of restoring homologous SP (5% and 10%) on the progressive motility, velocity, and chromatin integrity of SLC-selected stallion spermatozoa in 44 semen samples over time. Sperm progressive motility (P < 0.01) and the proportion with class A velocity (>50 μm/sec) were increased in samples where SP was restored, whereas the proportion with class B velocity (10 to 50 μm/sec) was decreased compared with SLC samples. However, after 24 h cold storage of treated samples, progressive motility was not different for the SP-treated groups compared with SLC, whereas chromatin damage DNA fragmentation index (%DFI) was higher. In contrast, adding SP to untreated 24 h-stored SLC samples did not affect progressive motility although it did increase the proportion of spermatozoa with class A velocity. There was individual variation between stallions whether 5% or 10% SP produced a greater increase in progressive motility. In conclusion, 5% to 10% SP can be added back to SLC-selected samples if considered necessary to optimize fertility. However, it should be added immediately before insemination rather than before storage of the sperm dose, to benefit from the transient increase in sperm progressive motility and avoid increased chromatin damage.
Barriers to the use of density gradient centrifugation for preparing animal spermatozoa for artificial insemination (AI) include the scarcity of animal-specific formulations and the daunting prospect ...of processing large volumes of ejaculate in small aliquots (1.5 ml extended semen). Recently, new colloid formulations have been tested in vitro in a modified procedure, centrifugation on a single layer of colloid. The present study investigated the fertilizing ability during in vitro fertilization (IVF) of frozen-thawed bovine spermatozoa following centrifugation through a single layer of glycerolpropylsilane (GS)-coated silica colloid with a species-specific formulation (patent applied for; treatment, T). Controls (C) included centrifugation through gradients of either the same colloid (C1) or Percolltrade mark sign (C2). Sperm recovery surpassed 50% for both C1-C2 and T (n.s.). Mean values of various parameters of computerized analysis of sperm motility did not differ between T and C1 (n.s.), and only the proportions of path straightness and linearity were lower in T vs C2 (p < 0.05). In T, the mean (±SD) percentages of fertilization rate, blastocyst development rate and the total number of blastomeres were 58.1 ± 23.3%, 24.5 ± 14.3% and 94.6 ± 23.4%, respectively. The proportions did not differ significantly from controls (C1/C2). Therefore, centrifugation through a single layer of colloid offers an alternative method to density gradient centrifugation for selection of viable, potentially fertile frozen-thawed bull spermatozoa. This single-layer technique is gentle, versatile and convenient because it facilitates scaling-up the process of sperm preparation to allow larger numbers of spermatozoa (for instance, whole ejaculates) to be processed for AI.
The development of a species-specific conservation protocol that involves artificial insemination with frozen semen needs to validate an effective methodology for freezing semen. Colloid ...centrifugation has been suggested and widely applied as an effective tool for selecting animal spermatozoa for artificial breeding. The objective of the present study was to compare different methods of centrifugation, single layer using Androcoll-Bear and Percoll and double layer using PureSperm 100 (in two different discontinuous gradients 40%–80% and 45%–90%), for the selection of fresh brown bear sperm samples. In the before freezing group, all selected samples showed a higher progressive motility and viability (except Percoll for motility 43.0 ± 5.3 P < 0.05); all colloids except PureSperm 45/90% rendered samples with fewer damaged acrosomes. In the after thawing group, all tested centrifugation colloids showed a good capacity to decrease the number of damaged acrosomes. Furthermore, PureSperm treatment (45/90%) resulted in an increase in apoptotic-like changes not only immediately after thawing but also after the incubation test, leading us to suggest that this gradient could induce some kind of deleterious effects on the sperm samples. On the other hand, PureSperm treatment (40/80%) yielded a quality preservation capacity similar to Androcoll-Bear in number of damaged acrosomes, different relative to the control (control, 5.3 ± 0.6; PureSperm 80, 2.0 ± 0.3; Androcoll, 2.1 ± 0.9 P < 0.05) but a decrease in the number of viable spermatozoa recovered after thawing relative to the control (control, 21.2 ± 3.1; PureSperm 80, 13.7 ± 2.7 P < 0.05). In conclusion, Androcoll-Bear constitutes a useful tool for handling of brown bear ejaculates owing to its simple handling and procedure with a reliable sperm selection and freezability. This colloid yielded an improvement in several sperm parameters in brown bear frozen-thawed semen; the selected spermatozoa of fresh samples with this colloid showed a better resistance to freezing compared with the control sample not only for motility but also for viability.
PDF
