Search

Contents [ABSTRACT FROM AUTHOR]

In a microchromosome-carrying laboratory stock of the normally all-female Amazon molly Poecilia formosa triploid individuals were obtained, all of which spontaneously developed into males. A comparison of morphology of the external and internal insemination apparatus and the gonads, sperm ploidy and behaviour, to laboratory-bred F hybrids revealed that the triploid P. formosa males, though producing mostly aneuploid sperm, are partly functional males that differ mainly in sperm maturation and sexual motivation from gonochoristic P. formosa males. [ABSTRACT FROM AUTHOR]

Contents Over the last few decades, rhinoceroses and elephants became important icons in the saga of wildlife conservation. Recent surveys estimate the wild Asian ( Elephas maximus) and African ( Loxodonta africana) elephant populations to be, at most, 50 250 and 637 600 respectively. For the five rhinoceros species, black ( Diceros bicornis), white ( Ceratotherium simum), Indian ( Rhinoceros unicornis), Javan ( Rhinoceros sondaicus) and Sumatran rhinoceros ( Dicerorhinus Sumatrensis), the population estimates of 3610, 11 330, 2400, 60 and 300, respectively, are of even greater concern. Protected against habitat loss, poaching and left undisturbed, rhinoceros and elephants reproduce well in the wild. But small and decreasing populations make successful captive management of these taxa increasingly important. In captivity, however, most populations face possible ‘extinction’ because of historically poor reproductive performance. From the first descriptions of the reproductive anatomy and the oestrous cycle ( Laws 1969 ; Kassam and Lasley 1981 ; Balke et al. 1988a,b ; Plotka et al. 1988 ; Godfrey et al. 1991 ) to the present use of advanced assisted reproduction technologies, researchers have strive to understand the function and dysfunction of the reproductive biology of these charismatic species. This paper reviewed the current knowledge on rhinoceros and elephant reproduction biology, reproductive cycle, gestation, dystocia, reproductive pathology, oestrous induction and artificial insemination, sperm sexing, IVF and contraception, and how this knowledge is or might be used to aid species conservation for maximal reproductive efficiency and enhancement of genetic management. [ABSTRACT FROM AUTHOR]

The freshwater tolerance of starry flounder Platichthys stellatus, stone flounder Kareius bicoloratus and their reciprocal hybrids, produced by artificial insemination, were examined in the larval, juvenile and immature phases. Survival rate on being transferred to fresh water in the pre-settlement phase was 0% in stone flounder and hybrids and 16·7% in starry flounder. This rate in the post-settlement phase was elevated to >50% in starry flounder and hybrids but was still 0% in stone flounder and similarly in the immature period starry flounder and hybrids survived in fresh water, although stone flounder did not. The lamella chloride cells of the gill epithelium increased in starry flounder and hybrids in fresh water in all periods. Densities of lamella chloride cells increased from 1·6 ± 0·4 (mean ±s.e. number of cells per 1 mm filament) before the transferral (day 0) to 60·3 ± 6·2 on 14 days after the transfer to fresh water (day 14) in starry flounder in the immature period. These densities in hybrids were 0·6 ± 0·3 and 1·0 ± 0·3 on day 0, and, 35·3 ± 2·8 and 23·2 ± 4·6 on day 14, respectively. Stone flounder did not show a substantial change in chloride cell densities throughout the experimental period. These results suggest that low salinity tolerance was well developed in the settlement period in starry flounder and hybrids, and hybrids were also adapted to fresh water sufficiently regardless of the cross type. [ABSTRACT FROM AUTHOR]

The structure of the seminal receptacles and associated accessory pouches in the reproductive tracts of four species of Australian ovoviviparous peripatopsids is described to identify features that may relate to their inferred mode of insemination. Euperipatoides rowelli is a dermal inseminator whereas Phallocephale tallagandensis, Ruhbergia bifalcata and Cephalofovea clandestina, species with head structures in males, are considered to be vaginal inseminators. Contrary to our expectations, E. rowelli, R. bifalcata and C. clandestina have very similar seminal receptacles and display two types of accessory pouches: funnel accessory pouches that open to the haemocoel and spherical accessory pouches in which destruction of excess sperm occurs. On the other hand, Ph. tallagandensis differs in the form of its accessory pouches. Although these pouches have no direct opening into the haemocoel, sperm were observed in the act of directly penetrating their walls to gain entry from the haemocoel. Hence, despite differences in the form of their accessory pouches, all species display features that provide the potential for entry of sperm into the female reproductive tract from the haemocoel. This finding has caused us to reconsider our initial assumptions of vaginal and dermal insemination as mutually exclusive reproductive strategies. Indeed, we propose that species of peripatopsids with head structures in males that were considered to be obligate vaginal inseminators may in fact be facultative, with vaginal insemination of sexually immature females when their uterus is short and free of developing embryos followed by dermal insemination to maintain the level of sperm in storage in the seminal receptacles. This study has also provided morphological evidence for mechanisms that may facilitate female control of paternity. [ABSTRACT FROM AUTHOR]

Contents Over the past decade, there has been increasing interest in the application of reproductive technology to the conservation and management of natural populations of deer. The application of assisted reproduction technologies within natural population of deer is in its infancy. However, its future potential is enormous, particularly in relation to genetic management or conservation. This paper reviews the present state of such technologies for a wild subspecies of red deer, the Iberian red deer ( Cervus elaphus hispanicus), by discussing the major components of oestrous synchronization, semen collection/cryopreservation and insemination techniques. In addition, findings made during the course of studies on natural populations have enormous potential for the understanding of novel reproductive mechanism that may not be uncovered by livestock or human studies. A summary of these results are also reviewed here. [ABSTRACT FROM AUTHOR]

The authors detail an experiment establishing the impact of insemination times on the fertilization rate and hatch rate of eggs of obscure puffer fish, Takifugu obscurus. Fertilization rates in highly matured ova are low. The authors conclude that insemination must be done within 4 hours of ovulation for better results.

Typhlodromus phialatus and T. exhilaratus are morphologically close species. Their differentiation is based on the shape of the insemination apparatus and on idiosomal setae length. However, the setae length values are often intermediate between these two species and do not allow accurate identification. Furthermore, the handful of differences in insemination apparatus shape are also questionable as a means of differentiation. Synonymy between these species has thus been questioned. Three experiments were carried out. Idiosomal seta length measurements, molecular tests and cross experiments were conducted for three populations, identified as T. exhilaratus and T. phialatus according to the shape of their insemination apparatus. The results show that the variation range of seta lengths is great and that these criteria do not allow accurate separation of these populations into two species. However, molecular tests show a species-level nucleotide differentiation between them. Cross experiments confirm this result, showing complete reproduction incompatibility between the mites bearing different insemination apparatus shapes. Therefore, T. exhilaratus and T. phialatus could be considered to be two valid species and the insemination apparatus could be considered as a pertinent diagnostic criterion at the specific level. [ABSTRACT FROM AUTHOR]

For decades, attempts to breed elephants using artificial insemination (AI) have failed despite considerable efforts and the use of various approaches. However, recent advances in equipment technology and endocrine-monitoring techniques have resulted in 12 elephants conceiving by AI within a 4-year period (1998–2002). The successful AI technique employs a unique endoscope-guided catheter and transrectal ultrasound to deliver semen into the anterior vagina or cervix, and uses the “double LH surge” (i.e., identifying the anovulatory LH (anLH) surge that predictably occurs 3 weeks before the ovulatory LH (ovLH) surge to time insemination. This study describes the 6-year collaboration between the National Zoological Park (NZP) and the Institute for Zoo Biology and Wildlife Research (IZW), Berlin, Germany, that led to the refinement of this AI technique and subsequent production of an Asian elephant calf. The NZP female was the first elephant to be inseminated using the new AI approach, and was the fifth to conceive. A total of six AI trials were conducted beginning in 1995, and conception occurred in 2000. Semen was collected by manual rectal stimulation from several bulls in North America. Sperm quality among the bulls was variable and was thus a limiting factor for AI. For the successful AI, semen quality was good to excellent (75–90% motile sperm), and sperm was deposited into the anterior vagina on the day before and the day of the ovLH surge. Based on transrectal ultrasound, ovulation occurred the day after the ovLH surge. Pregnancy was monitored by serum and urinary progestagen, and serum prolactin analyses in samples collected weekly. Fetal development was assessed at 12, 20, and 28 weeks of gestation using transrectal ultrasound. Elevated testosterone measured in the maternal circulation after 36 weeks of gestation reliably predicted the calf was a male. Parturition was induced by administration of 40 IU oxytocin 3 days after serum progestagens dropped to undetectable baseline levels. We conclude that AI has potential as a supplement to natural breeding, and will be invaluable for improving the genetic management of elephants, provided that problems associated with inadequate numbers of trained personnel and semen donors are resolved. Zoo Biol 23:45–63, 2004. © 2004 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

The silkworm, Bombyx mori, has a dimorphic sperm system. The eupyrene sperm is the sperm to fertilize eggs and the apyrene sperm plays a crucial role for assisting fertilization. Heat-treated (33°C for 96h) Daizo (DH) males, one of the strains in the silkworm, produce only eupyrene sperm, while in triploid males only apyrene sperm are functional. Though both types of males are found to be sterile, double copulation of the two males with a single female greatly increases fertility. Here we examined the fertilizing ability of eupyrene and apyrene sperm by means of an artificial insemination technique previously established in B. mori. Neither the eupyrene sperm collected from DH males, nor the apyrene sperm from triploid males have the ability to fertilize eggs. Artificial insemination with the mixture of eupyrene and apyrene sperm leveled up the frequency of fertilized eggs to more than 80%. When cryopreserved DH sperm (eupyrene sperm) were subjected to the same experiment, more than 95% fertilized eggs were obtained. These results confirmed that apyrene sperm play an important and indispensable role in fertilization in B. mori. Separate collection of functional eupyrene sperm and functional apyrene sperm and success of fertilization by means of the artificial insemination technique are applicable for further studies to elucidate the function of apyrene sperm. J. Exp. Zool. 297A:196–200, 2003. © 2003 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Optimum conditions for hydrostatic pressure treatment for duplication of chromosome set in gynogenetically activated fighting fish, Betta splendens (Regan), eggs were identified. Maximum survival of heterozygous gynogens was 50%, when 2.5-min-old eggs, after insemination with UV irradiated tilapia sperm, were pressure shocked at 7000 psi for 6 min. The frequency (21%) of homozygous gynogenetic fry was high, when the 34min (post-insemination) old eggs, which were inseminated with tilapia sperm, were pressure shocked for 5 min. Sex ratio of gynogenetic progeny suggested that the mechanism of sex determination in this fish is homogametic female and heterogametic male. [ABSTRACT FROM AUTHOR]

Triploidy was induced in the fighting fish, Betta splendens Regan, by varying all possible combinations of temperature (37–41°C), time after insemination (2–3 min) and shock duration (2–4 min). Heat shock at 39°C for 3 min duration initiated 2.5 min after insemination gave high frequencies of triploids (86%) as assessed from chromosome number and red blood cell nuclear volume. There was no significant difference in the growth rate of triploid and diploid fish. Gonadal development in both sexes was retarded in triploids at 5 months of age. Eggs fertilized with milt from triploids developed to gastrulation. Beyond gastrulation there was increasing mortality associated with abnormalities and none of them hatched. The display frequencies of air gulping, erection of operculum and fins, striking and biting, and undulating movements were fewer in triploids compared to diploids. It appears that triploids are less aggressive than diploids. The aggressive behaviour of fighting fish may be related Io their reproductive activity. [ABSTRACT FROM AUTHOR]

The sperm of tench, Tinea tinca L., is characterized by a milky colour and consistency, and is of very low density. After collecting the sperm, motion of spermatozoa was recorded even without water activation. A better motility value (value 4.36 on average) was observed in spermatozoa collected in immobilizing solution (collecting medium) and stored for 3h, when compared with spermatozoa without collecting medium. Average total and relative numbers of spermatozoa were 12.16 ⊗ 109 per male and 18.50 ⊗ 109 per kg of body weight, respectively. When testing the effect of activating solution in artificial propagation of tench, the highest fertilization rates (81.3 and 85% in two cases) were found for NaCl solution with an osmotic concentration of 34 or 69 mOsmol and for fresh water, respectively. The fertility rate was reduced significantly (P « 0.01) by any increase above 105 mOsmol in NaCl concentration in the activating solution. In the tests of optimal method of artificial fertilization, the highest hatching rate of sac fry (71.35%) was found in sperm collected into immobilizing solution. The application of immobilizing solution significantly increased the number of sac fry at the levels P«0.1 and P«0.01, if compared with intact sperm stored for 3 h and fresh sperm, respectively. [ABSTRACT FROM AUTHOR]

Most of the progress in female great ape reproduction has focused on monitoring ovarian and endocrine activity. Perhaps of more importance has been the gradually evolving interest and willingness to consider biotechnology as a potential, viable approach for enhancing reproductive performance. Artificial insemination (AI), in vitro fertilization (IVF), and embryo transfer offer an array of possibilities for combating infertility and understanding the fundamental differences and similarities among great ape species. Multidisciplinary efforts have assessed reproductive competence, from the simple (i.e., perineal tumescence and urinary occult blood in chimpanzees) to the complex (i.e., ovum recovery and IVF following exogenous hormone treatment in chimpanzees and gorillas). Hysterosal-pingography and laparoscopy have been used to determine uterotubal patency and to identify pathological conditions in gorillas. Assays for steroid metabolites in serial urine samples, to permit accurate assessments of ovarian cyclicity. have been developed and validated for all great apes species. Stimulation of follicular recruitment and maturation h4s been achieved following administration of clomiphene citrate (chimpanzees and gorillas) and human menopausal gonadotropin (gorillas), Clomiphene citrate and human chorionic gonadotropin have been used to regulate ovulation for the Al of chimpanzees. Pregnancies have resulted in chimpanzees and gorillas following Al using fresh and cryopreserved/thawed semen; however, conception rates vary. Embryos have been nonsurgically recovered from chimpanzees after timed matings and follicular oocytes have been recovered from chimpanzees and gorillas by transabdominal laparoscopy after exogenous hormone treatment. [ABSTRACT FROM AUTHOR]

The article reports on measures undertaken by Australian marine scientists to save the endangered grey nurse shark from extinction. Australian marine scientists are planning radical measures to prevent the extinction of the shark. Under the plan, a seven gill shark was artificially inseminated and monitored in an effort to perfect the technique for use in grey nurse sharks. In the next 10 years, Nick Otway and other marine biologists from the New South Wales State Fisheries Department will attempt to develop artificial uteri in which the shark embryos can develop. Researchers have found that grey nurse sharks exhibit intrauterine cannabilism; once the pups are about 10cm long, they have developed a fully functional set of jaws and teeth and they then set about trying to eat each other. Environmental groups such as the Humane Society International and the Nature Conservation Council have pointed out that on average, one grey nurse is killed every month either by shark nets or commercial and recreational fishing. Therefore, there is absolutely no point breeding sharks in test tubes without securing a safe place to release them in the wild.

In vitro fertilization of follicular oocytes harvested from ovaries and matured in vitro was attempted for 55 minke whales (Balaenoptera acutorostrata) captured for Japanese research purposes in the Antarctic Ocean during the period from November 1995 to March 1996. In Experiment 1, effects of culture duration (96 h or 120 h) on maturation of follicular oocytes and addition of caffeine (5 mM) and/or heparin (100 mu g/ml) on sperm penetration and pronuclear formation were investigated. Spermatozoa recovered from the vasa deferentia of four mature males were diluted (5-fold) and frozen at -80 deg.C. The post-thawed and pooled spermatozoa were used for in vitro insemination. A higher (P < 0.05) proportion of the oocytes cultured for 120 h (34.2%of 260) progressed beyond the second metaphase stage than of the oocytes cultured for 96 h (26.0% of 262). For the matured oocytes, higher rates of penetration (P < 0.05) and pronuclear formation (P < 0.01) were obtained in the oocytes cultured for 120 h (55.1% and 40.4%) than in those cultured for 96 h (32.4 % and 20.6916). Addition of caffeine and heparin did not show a significant effect. In Experiment 2, follicular oocytes matured for 120 h and then inseminated were cultured to examine the subsequent development in two culture systems (with and without co-cultured cumulus cells). Of 448 inseminated oocytes, cleaved embryos (2--16 cells) were observed with (5.8%) and without (4.9%) co-cultured systems. No cleavage was observed in 54 ova without insemination. These results indicate that in vitro fertilization of minke whale in vitro matured follicular oocytes with cryopreserved spermatozoa is possible, yielding cleaved embryos." [ABSTRACT FROM AUTHOR]