Vergelijking van twee kleuringsmethoden ter beoordeling van vaginale uitstrijkjes bij hond en kat

Vaginale cytologie is een nuttige diagnostische techniek vanwege de eenvoud en mogelijkheid om snel resultaten te verkrijgen. De voornaamste aanleiding voor het nemen van een uitstrijkje is het bepalen van het cyclusstadium bij teven. Het beoordelen van het staal gebeurt meestal door middel van een Diff-Quick (DQ)-kleuring, waarbij het in de praktijk niet altijd zo eenvoudig is om verhoornde of gekeratiniseerde cellen te differentiëren van niet-verhoornde. De Harris-Shorr (HS)-kleuring daarentegen is in staat cellen die keratineprecursoren bevatten, te differentiëren van overige celtypes, maar is omslachtig. In dit onderzoek werd een nieuwe, vereenvoudigde Harris-Shorr-kleuring vergeleken met de gebruikelijke Diff-Quick-methode. Uit de vergelijkende studie blijkt dat de correlatie tussen de verhoornde cellen (DQ) enerzijds en de som van de volledig rode cellen en >50% rode cellen (HS) anderzijds duidelijk positief is (rs (72) = 0,574 (p < 0,001)). Bijgevolg kan deze gemodificeerde Harris-Shorr-kleuring een meerwaarde betekenen in praktijkomstandigheden.

Gonadectomie 2.0: nieuwe inzichten over de langetermijneffecten bij honden

Argumenten tegen gonadectomie worden steeds vaker gehoord. Nieuwe studies tonen immers aan dat de ingreep voor de hond negatieve gevolgen kan hebben die op het eerste zicht niet rechtstreeks met het weghalen van de gonaden of de geslachtshormonen verband houden. In het voorliggende overzichtsartikel wordt de huidige literatuur over de langetermijngevolgen van gonadectomie op de gezondheid van de hond beschreven. De belangrijkste reden voor het ovariëctomiseren van een teef is de afname van het risico op pyometra en mammatumoren in vergelijking met intacte teven. De beschermende werking tegen mammatumoren is de reden waarom de operatie vaak op jonge leeftijd uitgevoerd wordt. Echter, in recent onderzoek werd aangetoond dat gewrichtsproblemen en bepaalde niet-genitale neoplasieën vaker voorkomen bij honden na gonadectomie, vooral bij prepuberaal geopereerde dieren. De resultaten van deze studies tonen grote rasverschillen aan, waardoor een algemeen advies over gonadectomie voor de hele hondenpopulatie niet realistisch is. De evolutie naar een ‘advies op maat’ dringt zich op.

Collection and cryopreservation of epididymal spermatozoa in dogs

When a male dog is not able to ejaculate, epididymal spermatozoa can be used to artificially inseminatethe bitch. In the present study, two methods to collect epididymal sperm after castration werecompared, i.e. the float-up method and the aspiration method. With the float-up method, more spermatozoawere collected than with the aspiration method (1810±718.1 million versus 694±244.5 millionrespectively, p-value = 0.018). A trend towards a higher post-thaw motility was observed when usingthe float-up method compared to the aspiration method (52±9.4% versus 44±9.4%, p-value = 0.060).Semen samples collected with the float-up method showed more blood contamination than with theaspiration method; however, this seemed to have no effect on the quality and quantity of the semen. Itcan therefore be concluded that the float-up method is the method of choice when epididymal spermhas to be collected in dogs.

Staalname en cryopreservatie van epididymale spermatozoa bij de hond

Wanneer een reu niet kan ejaculeren, kan epididymaal sperma gebruikt worden om een teef kunstmatig te insemineren. In deze studie werden twee methoden vergeleken om epididymaal sperma te verzamelen na castratie, namelijk de “float-up”-methode en de aspiratiemethode. Met de float-up-methode konden meer spermatozoa verzameld worden dan met de aspiratiemethode (1810±718,1 miljoen versus 694±244,5 miljoen respectievelijk, p-waarde = 0,018). Wanneer sperma verzameld werd met de float-up-methode, kon na het invriezen een trend tot een hogere motiliteit waargenomen worden dan met de aspiratiemethode (52±9,4% versus 44±9,4% respectievelijk, p-waarde = 0,060). Deze stalen vertoonden meer bloedcontaminatie dan de stalen verzameld met de aspiratiemethode. Dit bleek echter geen nadelig effect te hebben op de spermakwaliteit en -kwantiteit. Daarom kon geconcludeerd worden dat bij voorkeur de float-up-methode dient gebruikt te worden, wanneer epididymaal sperma verzameld moet worden bij honden.

Problemen omtrent partus en neonatale sterfte bij raskatten: een studie bij Vlaamse fokkers

Hoewel het fokken met raskatten aan populariteit wint, zijn weinig wetenschappelijke gegevens beschikbaar omtrent de partus en de problemen die hierbij kunnen optreden. In verschillende studies werd aangetoond dat kittensterfte bij fokkers varieert van 15 tot 40%. Aan de hand van een enquête bij fokkers werden in deze studie gegevens over 151 nesten verzameld van zes populaire rassen in Vlaanderen. De gemiddelde drachtduur bedroeg 65,1 ± 2,64 dagen. De gemiddelde nestgrootte bedroeg 4,5 ± 1,73 kittens. Kattinnen ouder dan vier jaar hadden een significant kleinere nestgrootte (3,6 ± 1,48 kittens) dan katten jonger dan vier jaar (4,8 ± 1,71 kittens) (P = 0,001). Bij 8,5% van de nesten werd bij de kattin een keizersnede uitgevoerd. Congenitale afwijkingen werden gerapporteerd bij 6,8% van de nesten. Het totale sterftepercentage tot de speenleeftijd bedroeg in de voorliggende studie 21,4%. Bij een kleinere nestgrootte (1-3 kittens: 12,2%), evenals bij grotere nesten (6-9 kittens: 7,3%) werd een significant hoger aantal doodgeboorten vastgesteld dan bij nesten van vier (4,8%) of vijf kittens (3,5%) (P = 0,016).

Semen donation and establishment of an open canine semen bank: a novel tool to prevent inbreeding in pedigree dogs

At present, only 5% of pedigree dogs is being used for breeding. To increase the number of breeding dogs, one solution could be to start a canine semen bank based on the principle of semen donation, like in humans. Many dog owners have no desire to become dog breeders but are willing to preserve the genetic material of their dog, if offered this possibility. However, not all canine ejaculates are suitable for cryopreservation as the initial quality may differ and the resistance of sperm cells to survive the freezing procedure is highly variable. In order to freeze the semen of as many male dogs as possible, it is important to optimize and individualize the cryopreservation protocol per ejaculate. Practically, frozen semen can be stored in the CanIfreeze-semen bank or in veterinary practices adjacent to the owner of the bitch and can be used for insemination at a later time.

Vraag & Antwoord

1. Castratie bij de reu 2. Sterilisatie bij de teef

Het bepalen van het optimale tijdstip voor keizersnede bij de hond in functie van de voorspelde partusdatum

Het optimale tijdstip bepalen voor de keizersnede bij de hond kan een uitdaging betekenen voor de praktijkdierenarts. Er moet rekening gehouden worden met de berekende partusdatum, het al dan niet op gang zijn van de partus en het al dan niet aanwezig zijn van dystocie. Sommige teven hebben een verlengde dracht, bij andere start de partus te vroeg. In beide gevallen is de kans op overleving van de pups zeer laag. Ook wanneer er bij dystocie te lang gewacht wordt om een keizersnede uit te voeren, komt de overleving van de pups in het gedrang. Het is daarom van groot belang de juiste partusdatum bij elke individuele hond te kunnen voorspellen, zeker bij risicopatiënten. De partusdatum kan berekend worden door het begin van de metoestrus te bepalen via vaginale cytologie of door embryonale en foetale structuren te meten via echografie. De meest accurate methode is echter door middel van cyclusopvolging met progesteronmeting.

Testiculaire aandoening van seksuele differentiatie (78,XX SRY-negatief) bij een vrouwelijke Franse buldog

Een tien maanden oude, vermeend vrouwelijke, intacte Franse buldog werd op de Faculteit Diergeneeskunde te Merelbeke (UGent) aangeboden met een vergrote clitoris en purulente vaginale uitvloei. Als therapie werd voorgesteld om de vergrote clitoris te verwijderen om verdere irritatie te vermijden en tegelijkertijd een gonadectomie uit te voeren aangezien de eigenaars geen fokplannen hadden. Intraoperatief werd een afwijkende genitaaltractus vastgesteld, waarbij macroscopisch een normaal uitziende baarmoeder aanwezig was maar waarbij de gonaden testes leken in plaats van ovaria. Histologisch onderzoek van het verwijderde weefsel toonde aan dat het inderdaad over bilaterale testes aansluitend op een normale baarmoeder ging. Karyotypering en de moleculaire analyse van het SRY-gen resulteerden in een 78,XX SRY-negatief karyotype. Bij de Franse buldog werd bijgevolg finaal een 78,XX SRY-negatief testiculaire aandoening van seksuele differentiatie, i.e. “disorder of sex development” (DSD) gediagnosticeerd.

Replacing serum in culture medium with albumin and insulin, transferrin and selenium is the key to successful bovine embryo development in individual culture

Individual culture of bovine embryos is usually associated with low blastocyst development. However, during preliminary experiments in our laboratory we observed high blastocyst development after individual embryo culture in a serum-free culture system. We therefore hypothesised that serum has a negative effect on embryos cultured individually whereas embryos in groups can counteract this. First, we determined whether the timing of removal of serum (during maturation or culture) had an influence on individual embryo development. The results clearly showed that removal of serum during embryo culture was the main contributing factor since high blastocyst development was observed after individual culture in synthetic oviductal fluid supplemented with bovine serum albumin (BSA) and insulin, transferrin and selenium (ITS), independent of the maturation medium. Second, we investigated whether an individual factor of the ITS supplement was essential for individual embryo development. We demonstrated that repeatable high blastocyst percentages were due to the synergistic effect of ITS. Finally, we investigated if a group-culture effect can still be observed under serum-free conditions. Group culture generated blastocysts with higher total cell numbers and less apoptosis. These data show that individual culture in serum-free conditions leads to high blastocyst development, but group culture still improves blastocyst quality.

251 IS THERE A GAP BETWEEN NUCLEAR AND CYTOPLASMIC MATURATION IN IN VITRO-MATURED EQUINE OOCYTES?

It is a general belief that as soon as the oocyte is recovered from the follicular environment, the nuclear maturation starts spontaneously in vitro, while specific stimulation for the cytoplasmic maturation is lacking (Gilchrist and Thompson 2007 Theriogenology 67, 6–15; Albuz et al. 2010 Hum. Reprod. 25, 2999–3011). As both nuclear and cytoplasmic maturation are required to prepare the oocyte for successful fertilization and embryonic development, a defective cytoplasmic maturation might be an important cause of low blastocyst rates in vitro (Albuz et al. 2010 Hum. Reprod. 25, 2999–3011). Nuclear and cytoplasmic maturation can be evaluated using fluorescent dyes. Assessment of nuclear maturation is typically based on the visualisation of chromatin, whereas cytoplasmic maturation is evaluated by the localization of cytoplasmic organelles [i.e. the cortical granules (CG)]. Equine oocytes were recovered from ovaries of slaughtered mares. After in vitro maturation (IVM; Smits et al. 2010 Vlaams Diergen. Tijds. 79, 134–138), oocytes were fixed and permeabilized. Subsequently, CG were labelled by incubation in 10 µg mL–1 FITC-labelled lens culinaris agglutinin during 15 min at RT. Chromatin was counterstained to verify the nuclear status with 20 µg mL–1 Hoechst 33342 during 15 min at RT. Stained oocytes with no or dispersed chromatin were classified as degenerated. Based on the absence or presence of the first polar body (PB), non-degenerated oocytes were either classified as nuclear immature (MI, no PB present) or nuclear mature (MII, PB present). The non-degenerated oocytes were further subdivided in 3 categories based on the migration of the CG: 1) cytoplasmic immature oocytes with (clusters of) CG randomly distributed throughout the ooplasm, 2) oocytes in transition stage with progressing CG migration to the oocyte cortex, and 3) cytoplasmic mature oocytes with a clearly visible CG monolayer just underneath the oolemma. The mean and standard deviation of nuclear and cytoplasmic parameters were calculated using Excel (Excel 2007, Microsoft Corp., Redmond, WA, USA). In 3 replicates, 86.6 ± 2.75% of all oocytes (131/151) demonstrated a corresponding nuclear and cytoplasmic maturation pattern (MI corresponding to CG1 and 2; MII corresponding to CG3). Only 12.0 ± 2.82% of the oocytes (16/133) revealed a cytoplasmic maturation pattern (CG 1 or 2) that lagged behind the nuclear maturation (MII). On the other hand, 22.2 ± 9.8% of the oocytes (4/18) were already cytoplasmic (CG3) but not yet nuclear matured (MI). Since most of the equine in vitro matured oocytes exhibited, surprisingly, a corresponding nuclear and cytoplasmic maturation pattern, it can be concluded that the gap between the nuclear and cytoplasmic maturation in vitro is less important than is generally believed. Consequently, the IVM step is not the main obstacle to increase the efficiency of the in vitro production process in horses.

1 AUTOCRINE COMMUNICATION BETWEEN BOVINE EMBRYOS CULTURED IN Primo Vision DISHES® OUTWEIGHS POSSIBLE NEGATIVE INFLUENCES OF BAD EMBRYOS

Group culture is being used extensively for mammalian embryos, but has not been adopted so far in human embryo culture. Some doubts about its possible benefits remain because it has been hypothesised that bad quality embryos might have a negative effect on other embryos. New group culture devices have been designed allowing individual follow-up of embryos, such as Primo Vision dishes® (well of-the-well for 10 embryos in group culture; Cryo-Innovation, Budapest, Hungary). By using Primo Vision dishes®, we investigated the influence of the developmental stage of the neighbours and co-cultured embryos on the outcome at 192 h post-insemination (hpi) of a particular embryo compared with its individually cultured counterparts. Bovine presumed zygotes (n = 789; 4 replicates) produced in vitro were randomly allocated to Primo Vision dishes® or individual culture in SOF supplemented with 0.4% BSA and insulin, transferrin, selenium (Wydooghe et al. 2013 Reprod. Fertil. Dev. Epub). Cleavage rate was checked at 45 hpi: 5- to 8-cell embryos were classified as fast embryos and 2- to 4-cell embryos as slow embryos. Blastocyst development was evaluated at 192 hpi. Moreover, to evaluate which embryos benefited most from being in group (fast or slow embryos), we looked retrospectively at the influence of the developmental stage of the neighbours and the co-cultured embryos on blastocyst development. This was done separately for slow and fast embryos compared with their individually cultured counterparts. Statistical analysis was done using a binary logistic regression model, with group and replicate as fixed effects. Blastocyst development in Primo Vision dishes® was significantly better than individual culture (39.0% v. 28.5%). This beneficial outcome was mainly caused by a higher blastocyst development of slow embryos. A markedly higher percentage of slow embryos developed into a blastocyst at 192 hpi if they were surrounded by many embryos that also developed into a blastocyst, compared with individually cultured slow embryos (odds ratio: 3.0). In this study, we showed that embryos that were not cleaved at 45 hpi did not negatively affect the potential of their neighbours to become a blastocyst at 192 hpi, regardless of whether the embryo in question was a fast or a slow embryo. However, when fast embryos were in a less than favourable environment, meaning that less than 30% of their co-cultured embryos reached the blastocyst stage, blastocyst development was compromised compared with individual culture of fast embryos (odds ratio: 0.3). From our results, we clearly show that Primo Vision dishes® can combine the benefits of group culture (autocrine communication) and individual culture (individual follow-up). Taking fast embryos out of the Primo Vision dish® for further individual culture while slow embryos remain in group is a possible approach to increase total blastocyst rates.

Vaginale cytologie bij de teef: een miskende techniek?

Vaginale cytologie bij de teef is gemakkelijk uit te voeren in de praktijk, de staalname is vrij eenvoudig en het is een relatief goedkope techniek met vele toepassingsmogelijkheden. Doordat de resultaten bovendien snel beschikbaar zijn, kan het praktijkdierenartsen helpen bij het beoordelen en het opvolgen van het cyclusstadium van een teef. Vaginale cytologie kan ook voor andere doeleinden gebruikt worden, zoals het voorspellen van het exacte partustijdstip, het bevestigen van een (ongewenste) dekking en het vaststellen van vaginitis, verlengde loopsheid, ovarieel restsyndroom, problemen post partum of vaginale neoplasie. Het optimale moment van dekking of inseminatie kan niet met vaginale cytologie bepaald worden en dient te worden uitgevoerd door middel van vaginoscopie en/of progesteronbepaling.

Vraag & Antwoord

Behandeling van klauwletsels bij runderen Brachyspira-infecties bij varkens Oestrussuppressie bij de kat

International breeder inquiry into the reproduction of the English bulldog

Dystocia may occur in all dog breeds, but the English bulldog is predisposed because of its conformation and specific problems such as anasarca pups. In this study, the frequency of abnormal pups and breeding problems in English bulldogs was investigated by a questionnaire containing information on 39 bitches in total. In 74.4% of these bitches, artificial insemination was performed. At the end of gestation, 25.8% of the bitches suffered from respiratory problems and partial anorexia. The average duration of gestation was 58.7 days counted from the first day of mating. Caesarean section was performed in 94.8% of the cases, with natural delivery in only 5.2% of the bitches. In this study, the average litter size was six pups. Thirteen percent of the pups were stillborn, 8.2% of the pups alive were deformed, with palatoschisis (38.8%) and anasarca (27.7%) being the most commonly observed abnormalities. Ten percent of the pups died before the age of weaning.

141 BOVINE EMBRYO CULTURE IN THE MODIFIED WELL OF THE WELL SYSTEM INCREASES BLASTOCYST RATE BUT LOWERS BLASTOCYST QUALITY

Individual culture of cattle embryos in serum-containing medium has a detrimental effect on blastocyst development. As we previously demonstrated, this effect is not caused by the individual culture itself but by some component present in serum (Heras et al. AETE Proc. 2012). The high blastocyst rates achieved with group culture in serum-containing medium can be explained by the neutralizing effect of the produced autocrine factors. Autocrine factors produced by individually cultured embryos cannot neutralize the detrimental component due to its low amount and their diffusion in the high culture volume. Using a modified well of the well (mWOW; Vajta et al. 2000 Mol. Rep. Dev.), where embryos are singly cultured in a small well, the effect of the autocrine factors produced by individual embryos can be maximized. We hypothesized that the use of mWOW for individual embryo culture in serum-containing medium, can maximize the neutralizing effect of the autocrine factors, increasing both blastocyst rate and quality. Bovine oocytes (n = 1143, 3 replicates) were matured in TCM-199 with 20% fetal bovine serum (FBS). Presumptive zygotes were cultured in groups (Gr; 25 embryos/50-µL drops), individually (Ind; 20-µL drops), or in mWOW (20-µL drops) in SOFaa with 5% FBS. Blastocyst evaluation occurred 7 and 8 days post-insemination (dpi). Hatching rate is the proportion of hatching/hatched blastocysts out of total 8-dpi blastocysts. Blastocysts were collected at 8 dpi for differential apoptotic staining, evaluating total cell number (TCN), inner cell mass (ICM) ratio, and apoptosis (ACR; Wydooghe et al. 2011 Anal. Biol.). Developmental data were analyzed using binary logistic regression; data concerning blastocyst quality were analyzed using linear mixed model analysis. Since ACR was not normally distributed, a logarithmic transformation was performed. Differences at P < 0.05 were considered significant. Regarding blastocyst development, all groups were significantly different both at 7 dpi (Gr 33.9%, Ind 10.7%, mWOW 19.6%) and at 8 dpi (Gr 37.3%, Ind 14.0%, mWOW 29.1%). Hatching rates were significantly higher in Gr (27.9%) compared to Ind (4.0%) and mWOW (4.1%). Concerning blastocyst quality, TCN was significantly higher (P < 0.001) in Gr (233.23 ± 8.39), no differences between Ind (143.77 ± 6.32) and mWOW (125.11 ± 4.30) were observed. No differences in ICM ratio were observed (Gr 0.41 ± 0.01, Ind 0.30 ± 0.02, mWOW 0.37 ± 0.02). ACR was significantly different between all groups (Gr 0.03 ± 0.002, Ind 0.04 ± 0.003, mWOW 0.08 ± 0.005). In conclusion, the mWOW had a positive effect on blastocyst quantity, increasing blastocyst rates compared to individual culture, but still lower than in group culture. Surprisingly, mWOW had a negative effect on blastocyst quality, producing the highest ACR and the lowest TCN. This negative effect can be caused by toxic products arising from the manufacture (although the wells were rigorously flushed), or by the longer manipulation time needed. This work was funded by FWO G.0210.09N and IWT g111438.

234 PREVALENCE OF MEMBRANE-DAMAGED CELLS IN BOVINE EMBRYOS AFTER CULTURE TO THE BLASTOCYST STAGE IN DEFINED MEDIUM

Autocrine factors are believed to be the reason why embryos cultured in a group show superior development compared with a single culture in many species. A widespread concern with group culture is that degenerating embryos may have a negative effect on the other embryos. Previously, we were able to identify some proteins in embryo-conditioned medium by using tandem mass spectrometry, predominantly stress-related proteins. Our hypothesis was that poor-quality embryos with membrane-damaged cells passively released these identified proteins into the medium. Therefore, we wanted to investigate what percentage of membrane-damaged cells occurred in an average population of Day 8 bovine embryos. Bovine presumed zygotes (n = 606) were cultured individually in 20-µL drops of modified SOF supplemented with insulin, transferrin, and selenium and 0.1 mg mL–1 of polyvinylpyrrolidone. At 8 days post-insemination, blastocyst development was evaluated, and subsequently, all embryos were stained with Hoechst/propidium iodide. In this way, we were able to detect the total cell number (TCN) and the percentage of membrane-damaged cells (MDC ratio) because propidium iodide will stain only the nuclei of membrane-damaged cells pink. Embryo-conditioned medium was collected individually and kept at –80°C until further analysis. At 8 days post-insemination, a blastocyst rate of 27.5% was observed. After determination of the TCN per embryo, we divided the embryos in two groups: 207 embryos had a TCN of more than 64 cells (normal development; range: 64 to 313 cells) and 399 embryos had a TCN of fewer than 64 cells (arrested development; range: 1 to 61 cells). In the first group, 76.3% (138 embryos) had an MDC ratio of less than 10%; however, only 11.1% (23 embryos) showed no membrane-damaged cells at all. In the group with arrested development, only 17.8% (71 embryos) of the embryos had an MDC ratio of less than 10%, and only 13.5% (54 embryos) had no membrane-damaged cells. Of the delayed embryos, 48.6% (194 embryos) showed an MDC ratio of more than 50%, and 34.5% (138 embryos) displayed even 100% of membrane-damaged cells. In conclusion, by use of Hoechst/propidium iodide staining, we were able to detect the TCN and MDC ratio of the embryos. We observed that only a small percentage of the embryos had an MDC ratio of 0%, even if the embryos had more than 64 cells. Almost half of the arrested embryos with fewer than 64 cells had a MDC ratio of more than 50%, indicating that poor-quality embryos consist predominantly of membrane-damaged cells that can passively release proteins into the medium, with a possible negative effect on the surrounding embryos in group culture. It must be noted, however, that for logistical reasons, these results were obtained in a single culture. Further research will be done to identify the candidate autocrine factors and proteins released into the medium by poor-quality embryos by analysing embryo-conditioned medium pooled according to the results of the Hoechst/propidium iodide staining.

Vraag & Antwoord

Leishmania bij honden in België Behandeling van schijndracht bij de teef Prototheca en geassocieerde uiergezondheidsproblemen

The importance of adequate fixation for immunofluorescent staining of bovine embryos

Immunofluorescent staining is often used to investigate the expression of specific proteins in pre-implantation embryos. The success of this method is determined by the specificity of the antibodies, but also by the protocol used for fixation and permeabilization of the samples. In this study, different fixatives are compared in combination with immunofluorescent staining of caudal-type homeobox 2 (CDX2), fibronectin 1 (FN1) and integrins (ITGs) on bovine blastocysts. For both CDX2 and the ITGs, the outcome of the staining was largely dependent on the fixation methods. Paraformaldehyde fixation was best for the intracellular CDX2 protein, whereas acetone fixation gave the best results for the transmembrane ITGs. No difference was observed for the FN1 staining between samples fixed with paraformaldehyde or acetone. These examples demonstrate that the choice of fixation and permeabilization agents is very important for the outcome of the experiment, and this choice is dictated by the (extra)cellular location of the protein under investigation. Inappropriate fixation and/or permeabilization methods can lead to erroneous conclusions regarding the site and amount of protein expression.