Characterization of basal seminal traits and reproductive endocrine profiles in North American river otters and Asian small‐clawed otters

Abstract

In this study, fecal samples were collected from 24 North American river (NARO) and 17 Asian small-clawed otters (ASCO) for 6-36 months and semen collected seasonally from NARO males (n=4/season) via electroejaculation. Our main objectives were to: (1) characterize endocrine parameters by longitudinal monitoring of fecal hormone metabolites and (2) investigate semen collection and basal seminal traits in NARO. NARO demonstrated a distinct seasonality in the spring, with females having a monoestrual estrogen elevation lasting 15.33+/-1.98 (mean+/-SEM) days and males peaking in testosterone production for 25.50+/-7.51 days. Pregnancy was characterized by 7-9 months of basal fecal progesterone, presumably corresponding to embryonic diapause, followed by a rapid increase over the final 68-73 days to term. Pseudopregnancy exhibited a similar late winter progesterone peak of 68-72 days, which could not be differentiated from pregnancy. Geographic latitude possibly influenced the timing of increased testosterone in males and increased progesterone in pregnant/pseudopregnant females. In ASCO, monitoring of fecal estrogens did not allow consistent detection of peak values associated with behavioral estrus. Both pregnancy and pseudopregnancy were characterized by a moderate rise in fecal progesterone for 14-16 days postovulation followed by a marked increase. Total gestation length was 67-77 days compared with 62-84 days for pseudopregnancy. In NARO, optimal sperm recovery and quality occurred only in the spring, corresponding with seasonal increases in testicular volume and fecal testosterone. These findings represent the first comprehensive information on normative endocrine and seminal traits in freshwater otter species.

Reproductive Features and Faecal Progesterone Metabolite Profile in Female Ferrets

“…This post‐partum elevation of faecal P 4 ‐met concentration seems to be one of the species‐specific characteristics of nursing females of certain carnivores with induced ovulation (ferret, Eurasian and Iberian lynx). A similar P 4 ‐met profile has not been observed in related species, like the domestic cat (Tsutsui and Stabenfeldt 1993) and the otter (Bateman et al. 2009).…”

“…2009; Jewgenow et al. 2009), elevated P 4 ‐met concentration in faeces and urine was reported to occur in post‐partum lactating lynxes (in both the Eurasian and the Iberian species), Bateman et al. (2009) did not find this phenomenon in otters (North American river otter, Lontra canadensis and Asian small‐clawed otter, Amblonyx cinereus).…”

“…North American river otters: Gross, 1992 cited by Schwarzenberger et al. 1996; Bateman et al. 2009; European minks: Möstl et al.…”

Characterization of the behavior and reproductive endocrinology of giant river otters (Pteronura brasiliensis) in managed care

“…Non‐invasive fecal hormone monitoring is a useful tool for understanding species‐specific reproductive endocrinology (e.g., Asa et al, ; Bateman et al, ; Brown, Bellem, Fouraker, Wildt, & Roth, ; Metrione, Norton, Beetem, & Penfold, ; Morrow, Wildt, & Monfort, ). In addition, behavioral and environmental evaluations can help determine whether encouraging or discouraging particular behaviors or modifying enclosures might enhance reproductive success (e.g., Carlstead & Brown, ; Metrione & Harder, ; Swaisgood, Dickman, & White, ; Terio, Marker, & Munson, ; Wielebnowski, Fletchall, Carlstead, Busso, & Brown, ).…”

Reversible meiotic arrest in feline oocytes

“…Although many of the observed effects were consistent with studies of other species, several unique responses were observed in feline oocytes, including the stimulation of meiosis by forskolin. Such species-specific effects emphasise the need for comparative studies, especially in taxa like Carnivora, where a variety of reproductive mechanisms exist and basic information concerning gamete and early embryo biology is limited (Desmarais et al 2004;Songsasen and Wildt 2007;Bateman et al 2009;Wildt et al 2010). Such studies will expand our understanding of reproductive biology, as well as allow for the development of alternative model species for studies of various reproductive processes.…”