Testicular Characteristics and the Block to Spermatogenesis in Mature Hinny.
Abstract: Most hinnies (female donkey×male horse) and mules (female horse×male donkey) are sterile with few reports of equine fertile hybrids. The main cause of this sterility is thought to be a meiotic block to spermatogenesis and oogenesis. This study compared the developmental features of the testes and a histological analyses of spermatogenesis in a male hinny with those of a normal, fertile stallion and Jack donkey. Hinny testes showed a thicker tunica albuginea, fewer blood vessels and more connective tissue in the testis parenchyma than those of the stallion and Jack donkey. Although the mean number of seminiferous tubules was significantly higher in stallion and hinny than Jack donkey (p<0.01), the mean proportion of seminiferous tubules was lower in the hinny (p<0.01) which resulted in a smaller diameter of seminiferous tubules. The mean number of spermatogonia and spermatocytes per unit area were significantly lower in hinny testis (p<0.01) and no spermatids or mature spermatozoa cells were found during immunofluorescent analyses. These results indicated that defects in seminiferous tubule development and structure occur in the testis of hinnies. Furthermore, most spermatogonia and spermatocytes cease development in synapsis during mid-meiosis of spermatocytes, which results in a block to spermatogenesis that prevents the formation of spermatids and matured spermatozoa during meiosis in male hinnies.
Publication Date: 2015-12-08 PubMed ID: 26954128PubMed Central: PMC4852245DOI: 10.5713/ajas.15.0670Google Scholar: Lookup
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Summary
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The research article explores the reasons behind the sterility in hinnies, a breed of horse-donkey hybrids, focusing on their distinctive testicular characteristics and problematic spermatogenesis process. Eluciduring the precise reasons why most hinnies fail to produce mature sperm, it points to anomalies in seminiferous tubule development and the abrupt ending of spermatocyte development.
Testicular Structural Differences
- Compared to fertile stallions and Jack donkeys, hinny testes show a thicker tunica albuginea, which is the dense protective outer layer of the testes.
- There are fewer blood vessels in the hinny testes, which may impact nutrient delivery and overall testes health.
- Hinnies have more connective tissue in the testis parenchyma, the functional tissue in the testes responsible for producing sperm.
Seminiferous Tubule Development
- Even though the mean number of seminiferous tubules, which are the site for spermatogenesis, was significantly higher in the stallion and hinny compared to Jack donkey,
- The proportion of seminiferous tubules in hinnies were less, which consequently leads to a smaller diameter of these tubules.
- These findings suggest that there are defects in the development and structure of the seminiferous tubules in the hinny testes hindering their fertility.
Spermatogenesis
- The study noted that the mean number of spermatogonia (primordial sperm cells) and spermatocytes (cells which undergo two divisions to become haploid sperm)- per unit area were significantly lower in hinny testes compared to the fertile control group.
- More strikingly, no spermatids or mature sperm cells were detected during immunofluorescent analyses.
- It was observed that most spermatogonia and spermatocytes cease development in synapsis during the mid-meiosis of spermatocytes.
- Consequently, it’s this stunted, interrupted development of spermatogonia and spermatocytes that creates a block in spermatogenesis and hinders the formation of mature sperm cells in male hinnies.
Cite This Article
APA
Han H, Wang A, Liu L, Zhao G, Su J, Wang B, Li Y, Zhang J, Wu B, Sun W, Hu S, Li S, Zhao L, Li X.
(2015).
Testicular Characteristics and the Block to Spermatogenesis in Mature Hinny.
Asian-Australas J Anim Sci, 29(6), 793-800.
https://doi.org/10.5713/ajas.15.0670 Publication
Researcher Affiliations
- Research Center for Animal Genetic Resources of Mongolian Plateau, Inner Mongolia University, Huhhot 010021, China.
- Research Center for Animal Genetic Resources of Mongolian Plateau, Inner Mongolia University, Huhhot 010021, China.
- Research Center for Animal Genetic Resources of Mongolian Plateau, Inner Mongolia University, Huhhot 010021, China.
- Inner Mongolia Saikexing Institute of Breeding and Reproductive Biotechnology in Domestic Animal, Huhhot 011517, China.
- Inner Mongolia Saikexing Institute of Breeding and Reproductive Biotechnology in Domestic Animal, Huhhot 011517, China.
- Inner Mongolia Saikexing Institute of Breeding and Reproductive Biotechnology in Domestic Animal, Huhhot 011517, China.
- Research Center for Animal Genetic Resources of Mongolian Plateau, Inner Mongolia University, Huhhot 010021, China.
- Research Center for Animal Genetic Resources of Mongolian Plateau, Inner Mongolia University, Huhhot 010021, China.
- Inner Mongolia Saikexing Institute of Breeding and Reproductive Biotechnology in Domestic Animal, Huhhot 011517, China.
- Research Center for Animal Genetic Resources of Mongolian Plateau, Inner Mongolia University, Huhhot 010021, China.
- Inner Mongolia Saikexing Institute of Breeding and Reproductive Biotechnology in Domestic Animal, Huhhot 011517, China.
- Research Center for Animal Genetic Resources of Mongolian Plateau, Inner Mongolia University, Huhhot 010021, China.
- Inner Mongolia Saikexing Institute of Breeding and Reproductive Biotechnology in Domestic Animal, Huhhot 011517, China.
- Research Center for Animal Genetic Resources of Mongolian Plateau, Inner Mongolia University, Huhhot 010021, China.
- Inner Mongolia Saikexing Institute of Breeding and Reproductive Biotechnology in Domestic Animal, Huhhot 011517, China.
- Inner Mongolia Saikexing Institute of Breeding and Reproductive Biotechnology in Domestic Animal, Huhhot 011517, China.
- Research Center for Animal Genetic Resources of Mongolian Plateau, Inner Mongolia University, Huhhot 010021, China.
- Inner Mongolia Saikexing Institute of Breeding and Reproductive Biotechnology in Domestic Animal, Huhhot 011517, China.
- Research Center for Animal Genetic Resources of Mongolian Plateau, Inner Mongolia University, Huhhot 010021, China.
- Inner Mongolia Saikexing Institute of Breeding and Reproductive Biotechnology in Domestic Animal, Huhhot 011517, China.
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Citations
This article has been cited 1 times.- Zhou H, Zeng Z, Koentgen F, Khan M, Mombaerts P. The testicular soma of Tsc22d3 knockout mice supports spermatogenesis and germline transmission from spermatogonial stem cell lines upon transplantation. Genesis 2019 Jun;57(6):e23295.
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