Effect of age and castration on serum anti-Müllerian hormone concentration in male alpacas

Anti-Müllerian hormone in female dromedary camel and its association with super-ovulatory response in embryo donors

Anti-Müllerian hormone (AMH) has a conserved role in regulating the reproductive cycle in several species. Its circulating concentration reflects the size of the growing primordial follicle reserve and is a reliable predictor of superovulation response in embryo/oocyte donors. This study investigated the possible application of AMH measurement in dromedary camels (Camelus dromedarius) multiple ovulation embryo transfer programs. In experiment 1, the follicular cycle of synchronized and naturally cycling camels (n = 12) was monitored. Blood was collected at 6 timepoints in 2 consecutive cycles corresponding to emergence, mid-cycle, and dominance in both group and hormonal fluctuations were evaluated for repeatability of measurements within and between cycles. In experiment 2, the correlation between circulating AMH concentrations prior to initiation of superovulation and the outcome of superovulation was evaluated. The results were compared between donors with higher (n = 7) and lower than median (n = 8) AMH values. Mean AMH concentrations in synchronized and non-synchronized camels were 1.46 ± 0.15 and 0.95 ± 0.09, respectively. Intercycle and intracycle values of AMH showed high repeatability in camels of both groups (>96.4% and >92.74%, respectively) with significant correlations between values at different stages of the ovarian cycle (Emergence and mid-cycle: R2 = 0.82; emergence and. dominance: R2 = 0.86; Mid-cycle and dominance: R2 = 0.93, P < 0.05). Total follicles, CLs, and recovered embryos were highly correlated with AMH values prior to superovulation (R2 = 0.64, R2 = 0.77, and R2 = 0.64, respectively, P < 0.05). A greater number of developed follicles prior to mating (17.00 ± 2.09 vs. 7.62 ± 1.06), CLs (12.58 ± 1.36 vs. 5.12 ± 0.93), transferable (10.85 ± 1,31 vs. 3.37 ± 0.82), and spherical embryos (8.14 ± 1.07 vs. 2.62 ± 0.7) were observed in camels with higher than median concentrations of AMH (P < 0.05). Fluctuations in estradiol and progesterone did not affect variations in mean AMH values (r2 < 0.19 and r2 < 0.24, respectively, P > 0.05). In conclusion, highly consistent AMH values in dromedary camels are a reliable predictor of superovulation response and outcome in dromedary camels.

Anti-Müllerian hormone levels in serum and testes of male dogs: relations with neuter status and bilateral abdominal cryptorchidism

Anti-Müllerian hormone (AMH) analysis has contributed to new information in the reproductive endocrinology of domestic animals, due to clinically available diagnostic tools. An accurate and rapid diagnostic method to distinguish between neutered and bilateral abdominal cryptorchid dogs is needed in veterinary practice. Therefore, this study uses an enzyme-linked immunosorbent assay to evaluate the clinical relevance of AMH analysis in peripheral blood as a diagnostic tool for dogs with suspected bilateral abdominal cryptorchidism. The possible alteration of the AMH localization in testicular tissue caused by this pathologic condition was also investigated using immunohistochemistry. Male dogs were divided into three groups of healthy intact (n = 14), healthy castrated (n = 14), and bilateral abdominal cryptorchid (n = 14) dogs. The results demonstrated a higher level of serum AMH in the cryptorchid group compared to the intact group (P < 0.01), while serum AMH levels of all castrated dogs were below the limit of detection (<0.05 ng/mL). Moreover, the percentage of positive AMH immunostaining of the intact group was less than that of the cryptorchid group (P < 0.01). A significantly positive correlation was found between serum AMH concentration and localization in testicular tissues (r = 0.93, P < 0.01). Our findings suggest that AMH levels in the peripheral blood could be used as an alternative and rapid screening method for detecting dogs with abdominal cryptorchidism.

Clinical use of Anti-Müllerian Hormone to monitor resumption of ovarian activity following removal of a 4.7 mg deslorelin implant in queens

OBJECTIVE

The use of deslorelin implants to control reproduction in cats is increasing but because of its prolonged duration, cat breeders often request implant removal before the end of the treatment. Assaying Anti Mullerian Hormone (AMH) concentrations might be useful to predict time of resumption of ovarian activity in deslorelin-treated queens following implant removal. In queens a minimum of 3 weeks during increasing photoperiod after implant removal has been described for resumption of ovarian activity but no information about AMH concentrations were observed for determining ovarian activity.

ANIMALS

Sixteen queens in which deslorelin implants were surgically removed after 3, 6 or 9 months (n = 6, 4 and 6 queens, respectively) were used in this study.

PROCEDURES

A general and reproductive health check with a GnRH stimulation test were performed before the treatment. After implant removal queens were checked every 1-2 weeks with reproductive ultrasonography, a vaginal smear and blood collection to assay AMH concentrations.

RESULTS

AMH concentrations decreased significantly at the end of the treatment to ≤ 2.5 + 0.6 ng/ml (p ≤ 0.05) and reached a nadir at 1.9 ± 0.9 (p < 0.05) one-week post-removal. Following implant removal AMH concentrations started to rise reaching a value of 3.9 ± 0.7 ng/ml on the third week and were not different from pre-treatment levels on week 6 post-removal (5.8 ng/ml + 0.9, p ≥ 0.05). AMH values did not differ depending on duration of deslorelin treatment but were lower in adult queens (p < 0.05).

CLINICAL RELEVANCE

AMH assay can be a useful tool to follow resumption of feline ovarian function following a deslorelin treatment.

Clinical and Histological Features of Ovarian Hypoplasia/Dysgenesis in Alpacas

Alpacas have a high incidence of congenital reproductive tract abnormalities, including ovarian hypoplasia/dysgenesis. Diagnosis of this condition is often challenging. The present study describes the clinical, ultrasonographic, and histologic features of ovarian hypoplasia/dysgenesis syndrome in 5 female alpacas. Additionally, serum AMH levels were compared between female alpacas diagnosed with ovarian hypoplasia/dysgenesis and a group of reproductively sound females (n = 11). The syndrome was suspected based on the presence of an infantile uterus and lack of ovaries by ultrasonography and laparoscopy. All females had normal female karyotype (n = 74 XX), but one presented a minute chromosome. The ovaries from these cases showed 3 main histological classifications: hypoplasia (n = 2), dysgenesis (n = 2), and dysplasia (n = 1). Serum AMH levels in affected females were significantly lower (P < 0.05) than those of reproductively sound control females. In conclusion, Serum AMH level may be helpful in the rapid diagnosis of ovarian hypoplasia/dysgenesis syndrome in alpacas. Furthermore, this syndrome in alpacas presents a variety of histological features. Different mechanisms may be involved in the derangement of ovarian differentiation. Further studies are needed to elucidate the causes of the syndrome.