SciCombinator

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Journal: Animal reproduction science

28

The camel seminal plasma contains a diverse array of components including lipids, carbohydrates, peptides, ions and proteins. These are essential for maintaining normal physiology of spermatozoa and are secreted mainly from the prostrate, epidydimis and bulbo-urethral glands of reproductive system. The protein profiles of camel seminal plasma were resolved by two-dimensional gel electrophoresis (2D-PAGE). The majority of the protein was found in acidic regions below pI 7.0 and the 19 brightly stained proteins were identified by MALDI-TOF/MS analysis. On the basis of proteomic profiles, β-nerve growth factor (β-NGF) was purified by ion-exchange and gel filtration chromatography and identified by SDS-PAGE and MALDI-TOF/MS analysis. It was further confirmed by western blotting experiments using rabbit anti-β-NGF primary antibody.

Concepts: Protein, Molecular biology, Western blot, Gel electrophoresis, Electrophoresis, Laboratory techniques, Two-dimensional gel electrophoresis, Isoelectric focusing

28

Ovulation in mammals involves pulsatile release of GnRH from the hypothalamus into the hypophyseal portal system with subsequent release of LH from the anterior pituitary into systemic circulation. Elevated circulating concentrations of LH induce a cascade of events within the mature follicle, culminating in follicle rupture and evacuation. The broad classification of species as either spontaneous or induced ovulators is based on the type of stimulus responsible for eliciting GnRH release from the hypothalamus. In spontaneously ovulating species (e.g., human, sheep, cattle, horse, pigs), release of GnRH from the hypothalamus is triggered when, in the absence of progesterone, systemic estradiol concentrations exceed a threshold. In induced ovulators (e.g., rabbits, ferrets, cats, camelids), release of GnRH is contingent upon copulatory stimuli; hence, ovulation is not a regular cyclic event. Since a classic 1970 Peruvian study, dogma has maintained that physical stimulation of the genitalia during copulation is the primary trigger for inducing ovulation in alpacas and llamas. Exciting results of recent studies, however, provide direct evidence for the existence of an ovulation-inducing factor (OIF) in semen, and compel us to re-examine the mechanism of ovulation in both induced and spontaneous ovulators. Ovulation-inducing factor in seminal plasma is a potent stimulant of LH secretion, ovulation and luteal gland development, and acts via a systemic rather than a local route. OIF is a protein molecule that is resistant to heat and enzymatic digestion with proteinase K. It has a molecular mass of 14kDa, and may be part of a larger protein complex or pro-hormone. The effect of OIF is dose-related and evident at physiologically relevant doses (i.e., as little as 1/100th that present in the ejaculate), and is mediated, in whole or in part, at the level of the hypothalamus in vivo. The factor exists in the seminal plasma of every species in which it has been examined thus far, including Bactrian camels, alpacas, llamas, cattle, horses, pigs, and koalas. Seminal plasma OIF does not appear to be a phylogenetic vestige in spontaneous ovulators since it (1) induced ovulation in pre-pubertal mice, (2) altered ovarian follicular wave dynamics in cows, and (3) elicited LH release in vitro from primary pituitary cell cultures of rats, mice, guinea pigs, rabbits, llamas and cows.

Concepts: Hypothalamus, Luteinizing hormone, Semen, Ovulation, Alpaca, Livestock, Gonadotropin-releasing hormone, Camelid

28

Despite their production potential and ability to survive on marginal resources in extreme conditions, dromedaries have not been exploited as an important food source. Camels have not been specifically selected for milk production, and genetic improvement has been negligible. High individual variation in milk production both within the population and within breeds provides a good base for selection and genetic progress. In this paper, we discuss the possibilities and constraints of selective breeding for milk production in camels, and include a summary of the use of embryo transfer at the world’s first camel dairy farm. Embryo transfer is an integral part of the breeding strategy at the camel dairy farm because it increases selection intensity and decreases the generation interval. Using high milk-producing camels as donors and low producing camels as recipients, 146 embryos were recovered (6.1±1.0embryos/donor; range: 0-18). Embryos were transferred non-surgically into 111 recipients (83 single and 28 twin embryo transfers). Pregnancy rate at 21 days and 5 months was 55% (61/111) and 45% (50/111), respectively. Finally, a total of 46 recipients delivered a live calf. These results document the utility of embryo transfer using high milk producing dromedaries as donors.

Concepts: Pregnancy, Milk, Cattle, Dairy farming, Livestock, Camel, Dromedary, Camelid

28

Embryo transfer in camels was initiated to respond to demand from the camel industry particularly in the United Arab Emirates since 1990. This paper reviews the research performed in critical areas of reproductive physiology and reproductive function evaluation that constitute a pre-requisite for a successful embryo transfer program. A description of donor and recipient management as well as a retrospective evaluation of calf production in the embryo transfer program at Sweihan, UAE is provided. The program utilized two management systems for donors, with and without ovarian superstimulation. Non-stimulated donors are flushed every 14-15 days with a mean embryo production per year per female of 8.5±3.1 (mean±SEM). Response to gonadotropin stimulation is extremely variable. FSH doses and frequency of administration is often adjusted to a specific female. In the period of 1990-2010, 11,477 embryos were transferred to recipients. Transfers from 1990 to 2009 (n=10,600) resulted in 2858 weaned calves, representing an overall efficiency (% weaned calves/transfer) of 27%. Pregnancy rates at 60 days post transfer varied from 19 to 44%. Pregnancy length following transfer is extremely variable. A major challenge in a large embryo transfer program is finding good quality recipients. Causes of pregnancy and neonatal losses are under study.

Concepts: Saudi Arabia, Arabian Peninsula, United Arab Emirates, Abu Dhabi, Dubai, Arab people, Ras al-Khaimah, Sharjah

28

Cryopreservation has been widely utilized in livestock and human embryos, which allows for storage of worthy embryos for a long period of time, although it is still uncertain as how long embryos can be cryopreserved in liquid nitrogen. The aims of this study were to evaluate the effects of long-term cryopreservation on birth rate of transferred sheep embryos at morula or blastocyst stage, and to investigate growth performance and viability of their offspring. A total of 373 sheep embryos from the same batch, which had been cryopreserved by conventional procedure for 0.5yr (n=259) or 7.5yr (n=114), respectively, were transferred to 373 recipient ewes. In parallel, artificial inseminations, acting as controls, were conducted in the same month in both years (n=81 and n=110) that embryo transfers were performed. Results showed that there were no significant differences in birth rate between short-term cryopreservation group (cryopreserved for 0.5yr in 2003) and long-term cryopreservation group (cryopreserved for 7.5yr in 2010) either at the morula or blastocyst stage (p>0.05). No specific differences in birth weight were observed among short-term cryopreservation, artificial insemination 1 (performed in 2003), long-term cryopreservation and artificial insemination 2 (performed in 2010) group (p>0.05). The weaning weights were similar between the short-term cryopreservation and long-term cryopreservation group (p>0.05). The mortality rates of the offspring were similar in both groups as well (p>0.05). We concluded that the long-term cryopreservation did not appear to adversely affect birth rate of the embryos, growth performance and viability of their offspring. Our results indicated that the cryopreserved sheep embryos should be stable in liquid nitrogen for at least 7.5 years.

Concepts: Time, Embryo, Artificial insemination, Livestock, Liquid nitrogen, Cryobiology, Cryopreservation, Ex-situ conservation

28

Gravid uteri harvested from 11 pregnant West African Dwarf goats at different stages of gestation were used to study the morphology of goat placentomal trophoblastic epithelium. The trophoblastic epithelium was composed of two trophoblast cell types; the mononucleate trophoblast cells and the binucleate trophoblast cells. Mononucleate trophoblast cells were tall columnar cells that rested on the basal lamina and extended to the foetomaternal interface, where their microvillar processes interdigitated with similar processes of the uterine epithelial cells to form the foetomaternal contact zone. Mononucleate trophoblast cells lining the arcade zones of placentomes contained erythrocytes in their cytoplasm. These cells are morphologically modified for acquisition of nutrients from the maternal compartment. Binucleate trophoblast cells showed two nuclei per cell and numerous characteristic membrane-bound granules in their cytoplasm. In addition, the binucleate cells resided in an intraepithelial position, showed evidence of capacity to migrate within the trophoblastic epithelium and fused with uterine epithelial cells at the foetomaternal interface. It would appear that the roles of the binucleate cells include formation of foetomaternal-derived hybrid cells in the placentomes and translocation of foetally synthesized substances across the placental barrier into maternal tissues via their migration and fusion with uterine epithelial cells. Furthermore this study demonstrated morphological modifications of the placentomal trophoblastic epithelium including extension of foetal blood capillaries into an intraepithelial position within the trophectoderm, such that they are situated close to the foetomaternal contact zone. This may enhance haemotrophic exchange of nutrients and metabolites between maternal and foetal blood circulations by reducing the diffusion distance between foetal and maternal blood capillaries.

Concepts: Childbirth, Fetus, Developmental biology, Epithelium, Basal lamina, Cervix, Placenta, Trophoblast

27

Two experiments were conducted to determine oviposition pattern and the effect of oviposition time on egg weight, body weight at hatch, and sex ratio of hatched chickens. In Experiment 1, eggs were collected from young and mid-age broiler flocks for 6 consecutive days at hourly intervals between 0400 and 2000h. In Experiment 2, eggs were categorized to represent eggs where oviposition occurred early, middle and late in the clutch (later in the day). These eggs were incubated to determine body weight at hatch and sex ratio of hatched chickens relative to oviposition time. Time of oviposition was affected by age. For the young flock, the percentage of ovipositions occurring before the 1100h was 79%. In contrast to the young flock, the percentage of ovipositions occurring before the 1100h in the mid-age flock was less (68%; P<0.01). Furthermore, for the mid-age flock, the percentage of ovipositions occurring from 1200 to 1700h was greater (P<0.01) at 32% in comparison to that of the younger flock at 21%. Egg weights when oviposition occurred earlier in the day were greater (P<0.01) than when oviposition occurred in the middle and later in the clutch (later in the day). Similarly, body weight at hatch of chicks from eggs where oviposition occurred earlier in the day was heavier than when oviposition occurred in the middle and later in the clutch (later in the day).With hatching of the eggs from hens when ovipositions occurred earlier in the day, there was a female sex bias. Differences in egg weights, body weight at hatch, and sex ratio due to time of oviposition suggest that oviposition time together with incubation conditions should be considered for obtaining greater uniformity and growth of chickens.

Concepts: Egg, Bird, Sex, Chicken, Meat, Hatch, Hatching

27

Here we report for the first time the possibility of sequential sperm motility activation in sturgeon (sterlet, Acipenser ruthenus), a fish with external fertilization, through changes either in osmolality (global solute concentration) or in the Ca(2+) concentration of the medium surrounding the spermatozoa. Sperm motility was initiated in any of three solutions containing buffer and sucrose at 80, or 40 or 10mM (called S80, S40, S10, respectively); S80 is hypertonic relative to sterlet seminal fluid, while S40 is isotonic and S10 is hypotonic. After cessation of sperm movement at the end of this first motility period, a second and then a third, subsequent motile phase were observed. The second motility period was induced at cessation of motility in S80 by imposing a two-fold decrease in osmolality. After arrest of motility in this half-diluted S80, a third motility period could be initiated by addition of CaCl2 to 1mM final concentration. At the end of a first motility period in either S40 or S10, subsequent motility re-activation episodes were achieved only by addition of 1mM CaCl2. Depending on conditions in which sperm samples were activated, significant differences in curvilinear velocity, percent motile spermatozoa, motility duration time, and specific external features of spermatozoa flagella were observed. Altogether, these observations on the ability of sturgeon spermatozoa to sustain sequential activation episodes by experimental adjustment of their environmental conditions represent a potent model for deeper investigations on the sperm motility activation mechanisms.

Concepts: Sperm, Concentration, Fertility, Spermatozoon, Semen, Sturgeon, Acipenseriformes, Sterlet

26

White rhinoceros ejaculates (n=9) collected by electroejaculation from four males were shipped (10°C, 12h) to develop procedures for the production of chilled and frozen-thawed sex-sorted spermatozoa of adequate quality for artificial insemination (AI). Of all electroejaculate fractions, 39.7% (31/78) exhibited high quality post-collection (≥70% total motility and membrane integrity) and of those, 54.8% (17/31) presented reduced in vitro quality after transport and were retrospectively determined to exhibit urine-contamination (≥21.0μg creatinine/ml). Of fractions analyzed for creatinine concentration, 69% (44/64) were classified as urine-contaminated. For high quality non-contaminated fractions, in vitro parameters (motility, velocity, membrane, acrosome and DNA integrity) of chilled non-sorted and sorted spermatozoa were well-maintained at 5°C up to 54h post-collection, whereby >70% of post-transport (non-sorted) or post-sort (sorted) values were retained. By 54h post-collection, some motility parameters were higher (P<0.05) for non-sorted spermatozoa (total motility, rapid velocity, average path velocity) whereas all remaining motion parameters as well as membrane, acrosome and DNA integrity were similar between sperm types. In comparison with a straw method, directional freezing resulted in enhanced (P<0.05) motility and velocity of non-sorted and sorted spermatozoa, with comparable overall post-thaw quality between sperm types. High purity enrichment of X-bearing (89±6%) or Y-bearing (86±3%) spermatozoa was achieved using moderate sorting rates (2540±498X-spermatozoa/s; 1800±557Y-spermatozoa/s). Collective in vitro characteristics of sorted-chilled or sorted-frozen-thawed spermatozoa derived from high quality electroejaculates indicate acceptable fertility potential for use in AI.

Concepts: Spermatozoon, Rhinoceros, White Rhinoceros, Black Rhinoceros, International Rhino Foundation, Northern White Rhinoceros, Southern White Rhinoceros, Ceratotherium neumayri

26

The aim of this study was to assess the synchrony in follicular wave emergence and subsequent ovulation following dominant follicle ablation or estradiol-17β administration. Six cycling Murrah buffaloes were sequentially allotted to three groups, that is, control, follicular ablation, and estradiol-17β groups. For the control group, buffaloes at random stages of estrous cycle were examined daily by transrectal ultrasonography for 14 days and the day of wave emergence was recorded. Following induced luteolysis and ovulation (Day 0), these buffaloes were included in the ablation group. All follicles (>5mm) were ablated on Day 3 or 5 or 7 (n=2 each day). Seven days after the ablation, these buffaloes were administered prostaglandin F2α to induce luteolysis and ovulation. Following this, buffaloes were included in the estradiol treatment group with estradiol administered on similar days as for ablation in the ablation group. Luteolysis was induced nine days after the estradiol injection. All animals of the treatment groups were subjected to transrectal ultrasound and blood samplings daily from treatment to induced ovulation. The follicular waves emerged significantly earlier (P=0.001) in both the ablation (2.1±0.79 days) and estradiol (4.0±0.25 days) treatment groups than the control group (8.3±0.88 days). The deviation from mean day of ovulation was greater (P=0.02) for the control group buffaloes (1.66±0.3 day) than those of the treatment groups (ablation, 0.76±0.2 and estradiol, 0.58±0.2 day). In conclusion, both ablation and estradiol resulted in synchronous emergence of a new follicular wave irrespective of stage at which the treatment was given, with greater synchrony of ovulations in water buffalo.

Concepts: Menstrual cycle, Ovarian follicle, Transrectal ultrasonography, Ovulation, Follicular phase, Bubalus, Water Buffalo, Ovulation induction