| 1. |
|
|
| 2. |
|
|
| 3. |
- Morrell, Jane, et al.
(författare)
-
Practical applications of sperm selection techniques for improving reproductive efficiency
- 2016
-
Ingår i: Animal Reproduction. - 1806-9614 .- 1984-3143. ; 13, s. 340-345
-
Konferensbidrag (refereegranskat)abstract
- Several selection techniques are available for processing spermatozoa. Apart from sperm washing to remove seminal plasma, only "swim-up" and colloid centrifugation have been used to any extent to prepare spermatozoa for in vitro fertilization, and only colloid centrifugation has been used to prepare sperm samples for artificial insemination. Single-layer centrifugation (SLC) through a species-specific colloid has been shown to be effective in selecting spermatozoa with good motility, normal morphology and intact chromatin in a range of species. This method is less time-consuming than swim-up, and has been scaled-up to allow whole ejaculates to be processed in a practical manner. The applications of SLC are as follows: to improve sperm quality in insemination doses or in samples for in vitro fertilization, to increase the shelf life of normal sperm doses, to remove pathogens ( viruses, bacteria), to improve cryosurvival by removing dead and dying spermatozoa before freezing or after thawing, to select spermatozoa for intracytoplasmic sperm injection, and to aid conservation breeding.
|
|
| 4. |
- Abraham, Maria Celina, et al.
(författare)
-
Breed influences on in vitro development of abattoir-derived bovine oocytes
- 2012
-
Ingår i: Acta Veterinaria Scandinavica. - : Springer Science and Business Media LLC. - 0044-605X .- 1751-0147. ; 54
-
Tidskriftsartikel (refereegranskat)abstract
- Background: There is a discrepancy in the reproductive performance between different cattle breeds. Using abattoir-derived ovaries and data base information we studied the effects of breed on in vitro fertilization and early embryo development. Methods: The in vitro developmental competence of oocytes from cattle (n = 202) of Swedish Red (SR), Swedish Holstein (SH) and mixed beef breeds was compared, retrospectively tracing donors of abattoir-derived ovaries using a combination of the national animal databases and abattoir information. Age was significantly lower and carcass conformation score was higher in the beef breeds than in the dairy breeds. Cumulus oocyte complexes (n = 1351) were aspirated from abattoir-derived ovaries from animals of known breed (visual inspection confirmed through databases), age (databases), and abattoir information. Oocytes were matured, fertilized (frozen semen from two dairy bulls) and cultured according to conventional protocols. On day 8, blastocysts were graded and the number of nuclei determined. Results: Cleavage rate was not different between the breeds but was significantly different between bulls. The percentage of blastocysts on day 8 was significantly higher when the oocyte donor's breed was beef or SR than SH. There was no significant difference in blastocyst grades or stages between the breeds, but the number of nuclei in day 8 blastocysts was significantly lower in SH compared to the beef. Conclusions: The use of abattoir-derived ovaries from animals whose background is traceable can be a valuable tool for research. Using this approach in the present study, oocyte donor breed was seen to affect early embryo development during in vitro embryo production, which may be a contributing factor to the declining fertility in some dairy breeds seen today.
|
|
| 5. |
|
|
| 6. |
- Abraham, Maria Celina, et al.
(författare)
-
Effect of sperm preparation on development of bovine blastocyst in vitro
- 2016
-
Ingår i: Zygote. - 0967-1994 .- 1469-8730. ; 24, s. 825-830
-
Tidskriftsartikel (refereegranskat)abstract
- colloids has been used to select normal sperm for assisted reproduction in several species. Animal models can sometimes be used as a preliminary step to investigate sperm preparation methods that are potentially of use for human fertility treatments. In this study bovine semen was prepared using three variants of the single-layer centrifugation sperm selection technique (Small, Mini, Mini-EP) with Bovicoll (Androcoll-B). Computer-assisted sperm motility analysis, the hypo-osmotic swelling test, and the sperm chromatin structure assay were performed on unselected (control) and SLC-selected sperm samples. Mini and Mini-EP gave the highest yield of motile spermatozoa, progressive motility and membrane integrity. In vitro fertilization trials were performed to investigate the fertilizing ability of the frozen-thawed bovine spermatozoa selected with Bovicoll. Mini-SLC (single-layer centrifugation) and swim-up (Control) were performed and cleavage rate and blastocyst rate did not differ significantly between groups. As there was a trend to an increased number of cells in blastocysts in the SLC group, the Mini-SLC method is at least as good as swim-up for selecting frozen-thawed bull spermatozoa for in vitro fertilization (IVF). This method could potentially be used to prepare human sperm for assisted reproduction.
|
|
| 7. |
- Abraham, Maria Celina
(författare)
-
Reproductive biotechnologies in Swedish male alpacas
- 2016
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Alpacas have become more popular during the last decades. The herds have been built up by importing live animals since reproductive biotechnologies, for example artificial insemination and semen preservation, are not well-developed in this species. A major problem is the viscosity of the seminal plasma which hinders processing or evaluation of the semen. Enzymes have been used to deal with the viscous seminal plasma but they may damage spermatozoa or render them incapable of fertilization. The use of reproductive biotechnologies would permit the introduction of new genetics without the need to import live animals, thus improving animal welfare and reducing the risk of spreading diseases. Therefore, our aim was to improve reproductive biotechnologies to help develop the Swedish alpaca breeding industry. Laboratory techniques were performed to select the best spermatozoa with Single Layer Centrifugation (SLC), in order to improve cryopreservation. These techniques were developed first using bull semen. There was an improvement in sperm quality in the SLC-selected samples, particularly from poor quality semen. In addition, the SLC technique could be modified to process small volumes. Alpaca epididymides were obtained after routine castration for husbandry purposes, with the intention of comparing semen extenders using extracted epididymal spermatozoa. Most of the organs came from pre-pubertal animals and therefore did not contain spermatozoa. Nevertheless, a decision-making tool for alpaca husbandry under Swedish conditions was developed. We suggest a combination of testicular size and body condition score as a tool for decision-making in the selection of potential sires for animal husbandry under Swedish conditions. A phantom was designed and built to collect semen samples in Sweden, and semen collection trials were also performed in Perú. The advantages and disadvantages of different semen collection techniques were evaluated. However, the problem with semen viscosity still has to be solved. Therefore a semen collection method should be established so that semen handling methods can be developed. We conclude that a phantom could be the best method to use for semen collection in Sweden, since it is a fairly simple technique and, as far as we are aware, there are no animal welfare concerns.
|
|
| 8. |
- Abraham, Maria Celina, et al.
(författare)
-
Semen collection methods in alpacas
- 2017
-
Ingår i: Veterinary Record. - : Wiley. - 0042-4900 .- 2042-7670. ; 180, s. 613-614
-
Forskningsöversikt (refereegranskat)abstract
- South American camelids, particularly alpacas, are gaining in popularity outside their native lands. Reproductive biotechnologies, such as artificial insemination or embryo transfer with cryopreserved embryos, are more complicated in these species than many others due to differences in their reproductive physiology compared to the more commonly encountered domestic livestock. This article reviews the methods currently available for obtaining semen or spermatozoa from alpacas and describes some of the problems associated with handling the viscous seminal plasma characteristic of camelids. Possibilities and limitations of reproductive biotechnologies in this species are discussed, and future developments are outlined, especially some new techniques which are currently being developed for use with camel semen and may be transferable to alpacas.
|
|
| 9. |
- Abraham, Maria Celina, et al.
(författare)
-
Testicular length as an indicator of the onset of sperm production in alpacas under Swedish conditions
- 2016
-
Ingår i: Acta Veterinaria Scandinavica. - : Springer Science and Business Media LLC. - 0044-605X .- 1751-0147. ; 58
-
Tidskriftsartikel (refereegranskat)abstract
- Background The popularity of alpacas (Vicugna pacos) is increasing in Sweden as well as in other countries; however, knowledge about optimal management practices under Swedish conditions is still limited. The wide age range reported when the onset of puberty can occur, between 1 and 3years of age, makes management decisions difficult and may be influenced by the conditions under which the alpacas are kept. The aim of this study was to find out when Swedish alpacas can be expected to start producing sperm, by using testicular length and body condition score as a more precise indirect indicator than age. Results This study suggests that animals with a testicular length ≥3.8cm would be producing sperm; however, if it is crucial to know that there is no sperm production for management purposes, the threshold level for testicular length used to differentiate between sperm-producing and non-sperm producing animals should be ≤1.6cm instead. If only one variable is considered, testicular length appears to better than age alone to predict sperm production. Body condition score together with testicular length explains the individual onset of puberty and better guide management recommendations. Conclusions Using a combination of these parameters (testicular length, body condition score and age) as a tool for decision making for alpaca husbandry under Swedish conditions is suggested.
|
|
| 10. |
- Al-Essawe, Essraa M, et al.
(författare)
-
Extenders for alpaca epididymal spermatozoa: Comparison of INRA96 and andromed
- 2020
-
Ingår i: Animal Reproduction Science. - : Elsevier BV. - 0378-4320 .- 1873-2232. ; 223
-
Tidskriftsartikel (refereegranskat)abstract
- Artificial insemination would be a useful technique for alpaca breeders to use as an aid to breeding to increase fleece quality. The technique, however, is not well developed in alpacas, partly because of the viscous nature of their seminal plasma. Castration conducted for husbandry purposes can provide a source of epididymal spermatozoa to test semen extenders or handling regimens, thus circumventing the problem of the viscous ejaculate. In this experiment, two semen extenders (Andromed and INRA96) developed for other species (bovine and equine, respectively) were tested with alpaca spermatozoa derived from the cauda epididymis. Sperm total motility (mean ± SEM A: 29.1 ± 4.8 % compared with I: 35.4 ± 4.8 %; NS), membrane integrity (A: 58 ± 9% compared with I: 56 ± 9%; NS) and acrosome integrity (A: 65 ± 7% compared with I: 54 ± 7%; NS) were not different between the two extenders. Progressive motility with use of INRA96 was greater after incubating for 30 min than after incubating for 10 min (35 ± 4% vs. 12 ± 4%, respectively; P = 0.03). In conclusion, viable epididymal spermatozoa could be extracted from the castrated organs after overnight transport. There were no differences in sperm quality between the two extenders; therefore, it appears that either extender could be used for alpaca spermatozoa. These results could help in the development of a technique for artificial insemination in alpacas.
|
|
