Khoboso Christina Lehloenya

Nonsurgical embryo recovery and transfer in sheep and goats

The embryo transfer techniques used in small ruminants worldwide are based in surgical procedures. These actions are performed under general anesthesia which needs a combination of animal fasting and drugs for secure animal handling and surgery manipulations. Therefore, it involves risks to animal health and life. The major limiting sequels are adhesions formed by the abdominal surgery, in the ovaries, uterus, or between them. These occurrences can both compromise uterus accessing and oocyte capture and are responsible for decreasing success and limiting successive embryo collections. In contrast, nonsurgical embryo procedures can be performed in a relatively simplified way. Nonsurgical embryo recovery does not need animal prolonged starvation, drug retention is minimized, and donors can stay in a standing position. After the end of embryo recovery, donors are promptly restored to their routine housing and feeding. Furthermore, this technique does not need incisions and, therefore, can be used repetitively in superovulated or nonsuperovulated goats and sheep for embryo recovery-a similar procedure done in cattle. In Brazil, promising results are reported using nonsurgical embryo transfer in recipient goats, and studies are currently evaluating similar procedures in sheep. Therefore, this review aimed to present the current panorama of nonsurgical embryo transfer in sheep and goats.

Consequences of endogenous and exogenous WNT signaling for development of the preimplantation bovine embryo

Abstract The specific role of WNT signaling during preimplantation development remains unclear. Here, we evaluated consequences of activation and inhibition of β-catenin (CTNNB1)-dependent and -independent WNT signaling in the bovine preimplantation embryo. Activation of CTNNB1-mediated WNT signaling by the agonist 2-amino-4-(3,4-(methylenedioxy)benzylamino)-6-(3-methoxyphenyl)pyrimidine (AMBMP) and a glycogen synthase kinase 3 inhibitor reduced development to the blastocyst stage. Moreover, the antagonist of WNT signaling, dickkopf-related protein 1 (DKK1), alleviated the negative effect of AMBMP on development via reduction of CTNNB1. Based on labeling for phospho c-Jun N-terminal kinase, there was no evidence that DKK1 activated the planar cell polarity (PCP) pathway. Inhibition of secretion of endogenous WNTs did not affect development but increased number of cells in the inner cell mass (ICM). In contrast, DKK1 did not affect number of ICM or trophectoderm (TE) cells, suggesting that embryo-derived WNTs regulate ICM proliferation through a mechanism independent of CTNNB1. In addition, DKK1 did not affect the number of cells positive for the transcription factor yes-associated protein 1 (YAP1) involved in TE formation. In fact, DKK1 decreased YAP1. In contrast, exposure of embryos to WNT family member 7A (WNT7A) improved blastocyst development, inhibited the PCP pathway, and did not affect amounts of CTNNB1. Results indicate that embryo-derived WNTs are dispensable for blastocyst formation but participate in regulation of ICM proliferation, likely through a mechanism independent of CTNNB1. The response to AMBMP and WNT7A leads to the hypothesis that maternally derived WNTs can play a positive or negative role in regulation of preimplantation development. Summary Sentence Endogenous WNTs are dispensable for blastocyst formation, but participate in the regulation of ICM proliferation, likely through a mechanism independent of β-catenin.

Cryopreservation of South African Indigenous Goat Semen

®V10 software. South African indigenous goats had total sperm cell motility rate of 83.1%, progressive sperm cell motility of 49.3% and non-progressive sperm cell motility of 33.9%. Moreover, acidic semen pH of 6.4 and low sperm cell concentration (663.6 × 10 6 /ml) were obtained. Removal of seminal plasma and semen cryopreservation significantly decreased pH (5.8 ± 0.1 and 5.7 ± 0.1 for frozen-thawed washed and not-washed, respectively) and sperm cell motility rates of South African indigenous goats. Reduction in the sperm cell motility after freeze/thawing is still a problem and requires further research on the diluents and techniques that give protection to sperm cells during cryopreservation.

Effect of breed and follicular status on response to superovulation in South African goats

ABSTRACT This study evaluated the effect of breed and follicular status of Boer and indigenous goats on response to superovulation and embryo yield. The oestrous cycles were synchronized with progestagen for nine days and superovulated with porcine follicle-stimulating hormone. Does were cervically inseminated and embryos were surgically flushed on day six following artificial insemination. The oestrous activity, ovarian response, embryo yield and quality, did not differ significantly between breeds. The number and size of follicles at the onset of superovulation treatment and during oestrus did not differ significantly between breeds. The follicles 2–3 mm, 4–5 mm and total number of follicles at the onset of superovulation treatment were positively correlated with the number of structures, embryos and transferrable embryos recovered. The number of medium follicles (4−5 mm) at the beginning of superovulation treatment increased the number of transferable embryos. The total number of follicles >6 mm at the onset of superovulation was positively correlated to the number of unfertilized ova. Although limited number of animals was used, the results suggest that breed has limited effect on superovulation response. Instead, the quality and yield of embryos are dependent on number and size of follicles present at the beginning of a superovulation treatment.

165 THE EFFECT OF INDIGENOUS CHICKEN EGG YOLK SOURCES AND TEMPERATURES ON SHORT-TERM PRESERVATION OF SOUTH AFRICAN INDIGENOUS GOAT SEMEN

Egg yolk is a common constituent of semen extender and protects sperm against cold shock. Besides its protective characteristic, chicken egg yolk is mostly included in extenders for semen preservation due to its abundant availability. The aim of the study was to compare egg yolk sources from different indigenous chicken egg yolk sources and storage temperatures on short-term preservation of South African indigenous goat semen. Semen was collected from 8 South African indigenous goats with artificial vagina during the breeding season (autumn). From each of the 8 goats, 6 replicates were done. Semen samples were randomly allocated into 4 treatment groups of Tris-based extenders containing 20% of egg yolk from White Leghorn as a control, Ovambo, Potchefstroom Koekoek, and Venda chicken breeds. The extended semen samples were stored at 5 or 25°C for 48h. Semen samples were evaluated for sperm motility using computer-aided sperm analysis sperm viability and morphology with fluorescence microscope at 0, 3, 24, and 48h. Data was analysed with ANOVA using Stata® version 12 (StataCorp, College Station, TX, USA) statistical software to test the differences between the treatments. The total, progressive, and rapid sperm motility rates were higher in freshly collected semen (90.6, 42.7, and 33.0%, respectively) compared with treatment groups. Semen extended with Tris without egg yolk had higher total sperm motility rate at both 5°C (48.1; 51.1%) and 25°C (43.3; 53.3%) temperatures for 48h. Semen extended with egg yolk from different egg yolk sources had no sperm motility from 24h when stored at 25°C. Semen extended with Tris without egg yolk (48.1%) had higher sperm motility than Ovambo, Potchefstroom Koekoek, Venda, and White Leghorn (3.7, 0, 0, and 0.4%, respectively) when stored at 5°C for 48h. However, sperm motility declined when storage increased. In conclusion, addition of egg yolk had no effect on preserving goat semen. However, Tris-based extender without addition of egg yolk preserved semen for longer period than semen extended with egg yolk regardless of egg yolk origin or chicken breed.