Theriogenology wild最新文献

{"title":"From salvage to science: Overcoming initial challenges and developing an adaptively managed program for an endangered amphibian, the mountain-yellow legged frog (Rana muscosa)","authors":"Leah E. Jacobs ,&nbsp;Stephanie Chancellor ,&nbsp;Barbara Durrant ,&nbsp;Ronald R. Swaisgood ,&nbsp;Debra M. Shier ,&nbsp;Natalie E. Calatayud","doi":"10.1016/j.therwi.2026.100151","DOIUrl":"10.1016/j.therwi.2026.100151","url":null,"abstract":"<div><div>The mountain yellow-legged frog (<em>Rana muscosa</em>) recovery program at the San Diego Zoo Wildlife Alliance emerged from crisis-driven salvage rather than a planned conservation framework, resulting in a genetically limited founder base and a long-term need for adaptive management. Over more than a decade, the ex-situ population functioned as an experimental system in which husbandry, genetic pairing strategies, and assisted reproductive technologies (ARTs) were iteratively refined to overcome persistent reproductive challenges including mismatched timing to gamete release among males and females, low annual output in viable offspring, and a narrow breeding season. Understanding the factors that limit reproductive success is essential for sustaining ex situ populations of the endangered <em>R. muscosa</em>. We combined ten years of natural-breeding records with four years of assisted fertilization (AF) trials to identify where along the reproductive sequence line-specific constraints arise and to develop AF protocols to further evaluate whether AF and crossing of populations (admixture) can help overcome potential issues restricting natural breeding, such as behavior incompatibilities, and help elucidate factors reducing breeding success. Natural breeding revealed consistent differences at the earliest developmental stage: San Jacinto (SJ) pairs produced higher embryo-formation rates than San Bernardino (SB) pairs, whereas tadpole hatching success was similar once embryos cleaved. Embryo formation success increased over time with refinements to hormone timing, brumation, and environmental cueing, and shorter latency to oviposition was associated with improved outcomes. Despite these gains, SB-sired clutches remained consistently low in embryo formation. AF trials confirmed this pattern; SJ and early-generation admixed males produced the highest embryo formation, whereas SB males performed poorly across all combinations. SB females, however, reproduced successfully when paired with SJ males, indicating that reduced fertilization success in SB lines is primarily driven by male gamete traits rather than female physiology or behavioral mismatches. These findings support the strategic use of directional admixture to maintain SB genetic representation while improving overall reproductive output. Integrating natural-breeding data, AF outcomes, and cryobanking strategies will help sustain viable ex situ lines and support the recovery of <em>R. muscosa</em> in the wild. This case study demonstrates that incremental, data-guided improvements, rather than single breakthroughs, are essential for developing effective amphibian ARTs under genuine conservation conditions.</div></div>","PeriodicalId":75220,"journal":{"name":"Theriogenology wild","volume":"8 ","pages":"Article 100151"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147537571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Insights for producing and future use of induced pluripotent stem cells from the small red brocket deer (Mazama jucunda)","authors":"Luana Scarpelini Rosa ,&nbsp;Laís Vicari de Figueiredo Pessôa ,&nbsp;Nayanne Sant Clair Cardoso da Silva ,&nbsp;Jenyffer Mairely Rosero ,&nbsp;Kaiana Recchia ,&nbsp;José Maurício Barbanti Duarte ,&nbsp;Fabiana Fernandes Bressan","doi":"10.1016/j.therwi.2026.100160","DOIUrl":"10.1016/j.therwi.2026.100160","url":null,"abstract":"<div><div>The small red brocket (<em>Mazama jucunda</em>), a deer endemic to the Atlantic Forest biome, is considered vulnerable by the IUCN, needing reproductive biotechnologies to preserve its genetic material. In this context, this study aimed to develop a proof-of-concept protocol for producing and characterizing induced pluripotent stem cells (iPSCs) originated from adult <em>Mazama jucunda</em> fibroblasts. Fibroblasts from skin biopsies were isolated and characterized regarding morphology and doubling time. Two transduction experiments were carried out with three technical replicates: transduction of eGFP reporter gene and transduction of pluripotency factors (murine OSKM - OCT4, SOX2, KLF4 and c-MYC) aiming for cellular reprogramming. This study successfully produced GFP+ cell lines, validating the transduction capacity of the lentiviral delivery system, as well as establishing a GFP+ cell line from the small red brocket, used for the OSKM transduction. In the OSKM transduction, cell aggregates with typical colony morphology were observed 33 days after the first transduction, however the colonies did not maintain classical characteristics in culture. Obtaining iPSCs from somatic cells is a very promising biotechnology and, currently, there has only been one report of iPSC induction in a cervid species, making studies such as these great contributions for better understanding reprogramming pathways in different deer species for future use in conservation programs.</div></div>","PeriodicalId":75220,"journal":{"name":"Theriogenology wild","volume":"8 ","pages":"Article 100160"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147991613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bull access influences fecal progesterone metabolites in managed female white rhinoceros (Ceratotherium simum): Insights from hormonal and behavioral monitoring at The Wilds","authors":"Shauni Windle,&nbsp;Dan Beetem,&nbsp;Cody Cseplo,&nbsp;Elizabeth Donelan,&nbsp;Kandace Krupp,&nbsp;Caitlin Consago,&nbsp;Terri L. Roth","doi":"10.1016/j.therwi.2026.100166","DOIUrl":"10.1016/j.therwi.2026.100166","url":null,"abstract":"<div><div>Refined husbandry has greatly improved reproduction in managed white rhinoceros, yet consistent breeding success remains a challenge. Social factors, particularly lack of mature bull access, are suggested contributors to reproductive challenges but supportive data is limited. At The Wilds, a large-landscape conservation center in Cumberland, Ohio, four postpartum multiparous and one nulliparous female white rhinoceros were monitored over a 10-month period. Fecal progesterone metabolite (fPM) assays and behavioral observations were conducted across three sequential conditions: indoor housing without a mature bull, pasture without a mature bull, and pasture with a mature bull. Baseline fPM values averaged 30 ± 1 ng/g in the postpartum, multiparous animals and 33 ± 3 ng/g in a nulliparous female. These values remained stable until a novel, mature bull was introduced, after which increases in fPM ranging from 131 to 174 ng/g, indicative of reproductive activity, were observed in four females following receptivity to mounting and copulation. A single smaller increase of 57 ng/g was recorded in the remaining female with limited reproductive behavior. Fecal testosterone metabolite analysis demonstrated that concentrations in the mature bull were significantly higher than those measured in the young males (<u>&lt;</u>3 years old) present throughout all conditions, thereby confirming the juvenile status of the latter. The results of this study suggest that the introduction of a mature bull can stimulate reproductive activity in female white rhinoceros following a prolonged period of quiescence.</div></div>","PeriodicalId":75220,"journal":{"name":"Theriogenology wild","volume":"9 ","pages":"Article 100166"},"PeriodicalIF":1.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148569210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of cryopreservation media on fertilization rate and post-thaw characteristics of tiger (Panthera tigris ssp.) spermatozoa","authors":"Shelley E.S. Sandmaier ,&nbsp;Jason R. Herrick","doi":"10.1016/j.therwi.2025.100133","DOIUrl":"10.1016/j.therwi.2025.100133","url":null,"abstract":"<div><div>There is a growing need for the development of assisted reproductive technologies to manage tiger populations under human care. Artificial insemination has been successful in tigers and other felid species but is ultimately reliant on the quality of the sperm sample. Cryobanking of tiger spermatozoa can aid in these efforts, but viability is reduced after thawing when compared to fresh samples. The current study tested new cryopreservation media with the goal of improving post-thaw viability and motility of tiger spermatozoa. Semen was collected by electroejaculation from 13 tigers and one or more treatments (TEST egg yolk buffer, soy, soy + glutamine, and soy + trehalose) were chosen for cryopreservation of each sample. Motility, acrosome integrity, and embryo development following heterologous in vitro fertilization (IVF) of domestic cat oocytes were evaluated to determine the effectiveness of each treatment. After thawing, none of the soy-based media improved upon these characteristics when compared to TEST egg yolk buffer. Despite low (average = 20 %) motility after thawing, all samples were capable of producing embryos via IVF. Results from this study indicate that both TEST and soy-based media can be used to cryopreserve tiger spermatozoa. However, there is still much room for improvement of sperm cryopreservation in this species.</div></div>","PeriodicalId":75220,"journal":{"name":"Theriogenology wild","volume":"7 ","pages":"Article 100133"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144489868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating alternatives to flow cytometry for sex-sorting rhinoceros sperm","authors":"Louisa A. Rispoli ,&nbsp;Elizabeth Donelan ,&nbsp;Parker M. Pennington ,&nbsp;Priscilla H. Joyner ,&nbsp;Terri L. Roth","doi":"10.1016/j.therwi.2025.100135","DOIUrl":"10.1016/j.therwi.2025.100135","url":null,"abstract":"<div><div>Effective sperm sex-sorting techniques could be beneficial for managing ex-situ rhinoceros populations. Fluorescence-activated cell sorting (FACS) technology has shown promise but is limited by high cost, long sorting times, and poor compatibility with frozen sperm. This study evaluated two alternative methods for sex-sorting sperm from white (<em>Ceratotherium simum</em>; n = 5) and greater one-horned (<em>Rhinoceros unicornis</em>; n = 5) rhinoceroses. Thirteen ejaculates (five fresh and eight cryopreserved) were used to assess Toll-like receptor (TLR) activation and magnetic-activated cell sorting (MACS). The TLR method selectively reduces X-bearing sperm motility via a TLR agonist, whereas MACS separates sperm based on Y-bearing sperm having a more positive surface charge than X-bearing sperm. The TLRs were confirmed to be present in rhinoceros sperm, with TLR7 primarily localized to the head region (90–95 %) and TLR8 to the flagellum (∼50 %). Activation with a TLR8 ligand reduced velocity (P = 0.001) but did not alter the distribution of X- and Y-bearing sperm in the upper and lower swim-up layers (P = 0.259). Negatively charged magnetic nanoparticles associated and pulled a portion of sperm to the tube wall when magnetic force was applied, leaving 35–80 % of sperm free in suspension, depending on the treatment conditions. However, no enrichment for X-bearing sperm was observed in the unbound fraction (P &gt; 0.27). These results indicate that neither method physically separated X- from Y-bearing rhinoceros sperm under the tested conditions. Nonetheless, the findings provide important foundational data for refining alternative methods for sex-sorting in this species and highlight both the potential and the challenges of applying such methods.</div></div>","PeriodicalId":75220,"journal":{"name":"Theriogenology wild","volume":"7 ","pages":"Article 100135"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144570603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First successful cervical artificial insemination in the European roe deer (Capreolus capreolus)","authors":"Sara Elsafadi ,&nbsp;Reto Giacometti ,&nbsp;Sandra Milena Bernal-Ulloa ,&nbsp;Susanne Holtze ,&nbsp;Sylvia Ortmann ,&nbsp;Davide Bosi ,&nbsp;Mara D. Saenz-de-Juano ,&nbsp;Alexander S. Leonard ,&nbsp;Hubert Pausch ,&nbsp;Frank Göritz ,&nbsp;Thomas Hildebrandt ,&nbsp;Susanne E. Ulbrich","doi":"10.1016/j.therwi.2025.100136","DOIUrl":"10.1016/j.therwi.2025.100136","url":null,"abstract":"<div><div>The European roe deer (<em>Capreolus capreolus</em>) is unique among artiodactyls for undergoing embryonic diapause, a 4–5 months period of reduced embryonic development at the blastocyst stage. However, our knowledge of the reproductive physiology and endocrinology of the seasonal roe deer, particularly regarding embryo development and diapause, remains limited. Addressing this knowledge gap is crucial and necessitates further advancements in reproductive technologies. Here, this case report documents the first successful artificial insemination resulting in a pregnancy and live birth in this species, marking a significant breakthrough in its reproductive management. The timing of artificial insemination was assessed through careful behavioral observations of the time of mating by a vasectomized teaser buck. Cervical insemination was then performed using frozen-thawed sperm collected earlier from a fertile buck. DNA sequencing of the progeny, the parents and non-related individuals in the herd confirmed the parent-offspring relationship between the fawn and the sperm donor buck. While this study serves as a proof of concept, it also identifies potential areas for enhancement, such as improving estrus detection methods, sperm handling techniques, and the insemination procedure itself. This research paves the way for advanced reproductive strategies in roe deer and potentially other species with similar reproductive characteristics.</div></div>","PeriodicalId":75220,"journal":{"name":"Theriogenology wild","volume":"7 ","pages":"Article 100136"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144865127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Endoscopic visual anatomy of urogenital tract in female Asian elephants (Elephas maximus)","authors":"Yaduraj Khadpekar ,&nbsp;Govind S ,&nbsp;Niraj Dahe ,&nbsp;Jorge Soares ,&nbsp;Nuhacet Fernández ,&nbsp;Tenzing L. Lachenpa ,&nbsp;Shubham Patil ,&nbsp;Akshay Ghatare ,&nbsp;Vaisakh Viswam ,&nbsp;Nikorn Thongtip ,&nbsp;Jahan Ahmed ,&nbsp;Nirmali Sarma","doi":"10.1016/j.therwi.2025.100121","DOIUrl":"10.1016/j.therwi.2025.100121","url":null,"abstract":"<div><div>Populations of Asian elephants (<em>Elephas maximus</em>) have been declining in the wild, mostly due to the habitat loss and conflicts with humans. The elephants under human care thus become a very important source and opportunity to study this species, as well as for the future conservation efforts through captive breeding and conservation programs. Although a lot of work has been done on the reproductive physiology of Asian elephants, there is a limited information available on the detailed anatomy of the reproductive tract. Endoscopy offers a direct visual observation of internal organs and examination of anatomy in live animals. We examined urogenital tracts of 30 female Asian elephants under standing sedation, with the flexible endoscope. The examinations were carried out as part of urogenital tract health assessment, and treatment of infections and pathologies. The distances of different parts from the external vulva opening, were measured. Detailed description of the visual anatomy of each of the urogenital tract parts through endoscope has been provided in this study.</div></div>","PeriodicalId":75220,"journal":{"name":"Theriogenology wild","volume":"6 ","pages":"Article 100121"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143474576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Faecal oestrone, rather than an androgen, is a sensitive and consistent marker of male reproductive state in equids","authors":"A.M. Burton ,&nbsp;J.A. Britnell ,&nbsp;G.K. Davies ,&nbsp;S. Shultz","doi":"10.1016/j.therwi.2025.100132","DOIUrl":"10.1016/j.therwi.2025.100132","url":null,"abstract":"<div><div>Measuring faecal steroid hormones can provide important information on reproductive state, health, and population demographics of wild and threatened species. Androgens are indicators of male reproductive state, dominance, and can provide sex and age metadata to samples. Steroids are difficult to measure in faeces, however, due to metabolism prior to excretion and to cross-reactivity. It is therefore essential to ensure faecal assays reflect biologically meaningful changes before using them in ecological settings. We assessed the suitability of four potential faecal biomarkers of male reproductive state in three equids: Grevy’s zebra (<em>Equus grevyi)</em>, Mountain zebra (<em>Equus zebra</em>) and Carneddau Mountain ponies (<em>Equus ferus caballus</em>). We used commercial enzyme immunoassays for three androgens: androstenedione, testosterone, epiandrosterone, and an androgen derived oestrogen, oestrone, to evaluate variation between reproductively mature and immature males. Surprisingly, faecal oestrone showed the best discrimination between male reproductive classes in all species, with higher Z-scores in reproductive males compared to foals. Neither faecal testosterone, androstenedione, nor epiandrosterone could discriminate between reproductive classes. We also observed seasonal variation in Carneddau pony stallions preceding the breeding season for oestrone and androstenedione, and found high individual variation in repeated samples from Grevy’s zebra. Finally, we compared faecal oestrone between stallions and mares; non-pregnant mares had lower oestrone than stallions but there was only a significant difference between stallions and pregnant females in Grevy’s zebra. Our results suggest that faecal oestrone, rather than an androgen, is a more optimal biomarker of male reproductive state in equids. Our study highlight the importance of ensuring faecal steroid measurements are biologically and ecologically meaningful within wildlife endocrinology.</div></div>","PeriodicalId":75220,"journal":{"name":"Theriogenology wild","volume":"7 ","pages":"Article 100132"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144489808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study of fecal progesterone metabolites in captive and reintroduced bantengs (Bos javanicus birmanicus) in Kanchanaburi, Thailand","authors":"Weerapun Nokkaew ,&nbsp;Apiradee Intarapak ,&nbsp;Seree Nakbun ,&nbsp;Nucharin Songsasen ,&nbsp;Nikorn Thongthip","doi":"10.1016/j.therwi.2025.100122","DOIUrl":"10.1016/j.therwi.2025.100122","url":null,"abstract":"<div><div>Understanding species’ reproductive biology is important for animal propagation, and the non-invasive technique of measuring fecal progesterone is a useful method for assessing reproductive health in wildlife. In this study, ovarian cycles of the captive bantengs and reproductive health of the reintroduced individuals were evaluated by assessing fecal hormone metabolites. A year-round examination of the ovarian cycles of four female bantengs (<em>Bos javanicus birmanicus</em>) housed <em>ex situ</em> was conducted by fecal progesterone metabolites detection. Furthermore, the means of fecal progesterone level were compared between females housed under human care and reintroduced individuals. Results revealed year-round estrous cycles in <em>ex-situ</em> females, unless interrupted by pregnancy. Average fecal progesterone metabolites (mean ± standard error of mean [SEM]) during the luteal phase of the four females (F1, F3, F4 and F8) were 1227.42 ± 167.45, 385.80 ± 46.55, 632.59 ± 44.19, and 872.4 ± 136.8 ng/g of dry feces, with average estrous cycle intervals of 21.14 ± 1.17 days. Mean baseline concentrations of fecal progesterone metabolites were 594.35 ± 422.59, 93.12 ± 51.71, 216.90 ± 64.92 and 166.17 ± 113.45 ng/g of dry feces, respectively. Mean fecal progesterone levels were approximately 4-fold greater (<em>P</em> &lt; 0.001) during pregnancy than the non-pregnant period (pregnancy: 2399.35 ± 317.27 ng/g; non-pregnancy: 675.31 ± 107.8 ng/g). Mean progesterone concentration was higher (<em>P</em> = 0.028) in reintroduced females than in <em>ex-situ</em> individuals. This study advances the understanding about banteng reproductive biology, information that is critical for assessing reproductive health of both captive and reintroduced populations.</div></div>","PeriodicalId":75220,"journal":{"name":"Theriogenology wild","volume":"6 ","pages":"Article 100122"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143579555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Follicular fluid supports cumulus expansion in post-mortem recovered cumulus-oocyte complexes of Hippopotamus amphibius","authors":"Judith Diaz-Muñoz ,&nbsp;Sonia Gago ,&nbsp;Paula Serres-Corral ,&nbsp;Bruna Oliveras-Seguí ,&nbsp;Vanessa Almagro ,&nbsp;Teresa Mogas ,&nbsp;Manel López-Béjar","doi":"10.1016/j.therwi.2025.100125","DOIUrl":"10.1016/j.therwi.2025.100125","url":null,"abstract":"<div><div>Assisted reproduction is essential for the conservation of wildlife species. While obtaining oocytes from living individuals can be challenging, the retrieval of post-mortem ovaries provides a valuable alternative for developing reproductive protocols that could enhance preservation efforts. In this study, we aimed, to evaluate the impact of follicular fluid (FF) supplementation during <em>in vitro</em> maturation (IVM) on nuclear maturation and cumulus expansion of common hippo (<em>Hippopotamus amphibius</em>) oocytes<em>.</em> Ovaries were recovered during the post-mortem examination of a 33-year-old female hippo, and 44 oocytes were collected and randomly allocated into three groups for IVM. A control group matured in standard media, a Small-FF group with control standard supplemented with 10 % follicular fluid from small follicles, and a Large-FF group with standard media supplemented with 10 % follicular fluid from large follicles. Images were taken at 0, 16, and 24 h of IVM to evaluate cumulus expansion by measuring the diameter of each cumulus-oocyte complex (COC). Following 24 h of IVM, polar body (PB) extrusion was assessed. Results showed a significant increase in cumulus expansion in the FF-supplemented groups compared to the Control (16 h: Control: 13 ± 4 %, Small-FF: 43 ± 13 %, Large-FF: 44 ± 6 %; 24 h: Control: 27 ± 7 %, Small-FF: 71 ± 15 %, Large-FF: 66 ± 9 %). The Small-FF group (46.1 %) and Control group (40 %) exhibited similar percentages of PB extrusion, while PB could be observed in 6.3 % of the Large-FF group. These findings suggest that while FF supplementation promotes cumulus expansion, the size of the follicle from which the fluid is derived may significantly influence oocyte ability to achieve PB extrusion</div></div>","PeriodicalId":75220,"journal":{"name":"Theriogenology wild","volume":"6 ","pages":"Article 100125"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143628642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}