Ultrasonographic and hormonal characterization of reproductive health and disease in wild, semiwild, and aquarium-housed southern stingrays (Hypanus americanus)

Abstract

OBJECTIVE To characterize physical examination, plasma biochemical, and ultrasonographic findings in aquarium-housed, managed semiwild, and wild southern stingrays (Hypanus americanus) with and without reproductive disease. ANIMALS Southern stingrays from aquarium (n = 48), lagoon (managed semiwild; 34), and wild (12) habitats. PROCEDURES Limited, opportunistic prosections were performed of presumed anatomically normal wild southern stingrays and compared with findings for aquarium-housed stingrays with reproductive disease. Ultrasonographic video data from both groups were used to assign a score (1 to 5) indicating increasing severity of ovarian and uterine reproductive disease. Plasma total 17β-estradiol, estrone, progesterone, and testosterone concentrations were measured with enzyme immunoassays validated for use in southern stingrays. RESULTS Ultrasonographic ovarian scores were significantly correlated with uterine scores. No reproductive disease was detected in semiwild or wild stingrays, but 65% (31/48) of aquarium-housed stingrays had developing or advanced reproductive disease (ie, ultrasonographic ovarian or uterine score of 4 or 5). Significant correlations were identified between ovarian and uterine disease status and plasma concentrations of all steroid hormones except testosterone. CONCLUSIONS AND CLINICAL RELEVANCE Findings suggested that ultrasonography and plasma hormone concentrations may be useful in the identification of reproductive disease and determination of disease severity in southern stingrays.

Steroid hormones and chondrichthyan reproduction: physiological functions, scientific research, and implications for conservation

“…This can be partially explained by the limitation in tissue mass, financial support, available antibodies, and methods for the simultaneous analysis of a larger quantity of hormones using the same biopsy. Systematic research using captive model species under controlled environments can clarify the function of E2, T and P4 on specific biological phenomena, while the combination of methods could Although the obtained information is highly valuable for present and future comparisons, the potential bias in terms of cross reactivity should be considered (Nozu et al, 2015(Nozu et al, , 2017Mylniczenko et al, 2019). Sharks, rays and chimaeras depose urea and other metabolic waste such as trimethylamine oxide in the blood (Compagno, Dando & Fowler, 2005;Nelson, Grande & Wilson, 2016).…”

“…3). Minimum and maximum number of specimens were 2-81 for males (Nozu et al, 2017;Wyffels et al, 2019) and 3-94 for females (Nozu et al, 2015;Mylniczenko et al, 2019). All papers with EIA/ELISA as the main analytical method mentioned the antibodies used and constitute 13.6% (n = 8) of the reviewed literature.…”

What is your diagnosis? Reproductive tract fluid from a radiated tortoise (Astrochelys radiata) and southern stingray (Hypanus americanus)

“…A 14-year-old female nulliparous southern stingray (Hypanus americanus) (Case 2) was presented to the veterinary team at The Seas with Nemo and Friends for evaluation of ongoing stage 5 polycystic ovarian disease with follicular retention and hydrometra. 1 Initially, the ovarian disease was managed with oral and injectable progestin. Within the last 2 years, gonadorelin and PGF2α were cyclically added to induce ovulation and decrease cystic volume.…”

Initial Characterization of Male Southern Stingray (Hypanus americanus) Reproductive Parameters and Preliminary Investigation of Sperm Cryopreservation

“…Southern stingrays are popular in aquariums and are relatively easy to handle, facilitating health and reproductive examinations. Previous work has focused on the reproductive biology of female southern stingrays [ 7 ] and with the exception for copulatory behaviours [ 8 ], male reproductive characteristics in this species have not been described. Semen characteristics, including pH, osmolarity, sperm concentration and motility, have previously been described in freshwater stingray species [ 9 , 10 ], but otherwise little information is available on semen parameters of male ray species.…”

“…Until recently, many elasmobranch studies have been conducted post-mortem, but it has been recognized that non-lethal sampling should replace these methods [ 11 ]. Semen collection, hormone analysis and ultrasound examinations on live specimens are becoming more prevalent for investigating the reproductive biology of elasmobranch species, including the southern stingray [ 7 , 12 , 13 ]. In addition, ultrasonography can be a useful tool in assessing body condition, an indicator of reproductive function in elasmobranch species [ 12 ].…”