104 The effect of interspecific hybridization on the development of testes in genus Ovis males

Abstract

Interspecific hybrids, especially males, are sterile or have reduced fertility. The structure and development of reproductive organs is species-specific. The study of development stages, morphology and biometric parameters in the male testes, the characterisation of species features, and the development of assisted reproductive technologies is of great importance. The aim of this research was to study morphometric parameters of the testes of interspecific hybrids of Argali with sheep of the Romanov breed compared with the original Romanov breed. The objects of research were purebred males of the Romanov breed (n = 8) and hybrid males with the following genotypes: 1/4 Argali × 3/4 Romanov (Group I, n = 10), 1/8 Argali × 7/8 Romanov (Group II, n = 12). The collection of testes from purebred and hybrid animals was carried out at castration (age = 12 months). Testicular tissue was fixed in Bouin’s solution. The following metrics were evaluated: weight and morphometric parameters of the testis, diameter of the seminiferous tubules, and the number of spermatogenic cells in the seminiferous tubule. Statistical analysis (comparison between groups with t-test and ANOVA) was performed using SPSS vs.15.0 (SPPS Inc.). The weight of testes in purebred Romanov males averaged 393 ± 41 g. In hybrid animals from groups I and II, this indicator was lower compared with that of purebred animals, by 58% and 41% (P < 0.01), respectively. The average circumference of the testes in purebred animals and hybrids of groups I and II was 26 ± 2, 19 ± 3 and 20 ± 3 cm. The diameter of the seminiferous tubules in purebred animals and in hybrids of groups I and II was 215 ± 3, 121 ± 2 and 170 ± 6 µm, respectively. The number of spermatogenic cells inside the seminiferous tubules affects their size. In purebred animals, this value reached 90 ± 3 cells. Hybrid animals in Groups I and II were inferior to their purebred peers in the number of spermatogenic cells in the seminiferous tubules by 31% (P < 0.01) and 9%, respectively. The obtained results indicate the influence of individual characteristics of males on testicular morphology, including the number of spermatogenic cells in the seminiferous tubules.

The studies were carried out with financial support from the Russian Science Foundation, grant No. 18-16-00079 and the Ministry of Science and Higher Education of the Russian Federation.