172 Testicular morphometry from prepubertal to adulthood in alpacas
H. Cucho A B , A. Tibary C and E. Mellisho AA Laboratory of Histology and Cytology, Centro de Investigación en Tecnología de Embriones, Universidad Nacional Agrária La Molina, Lima, Perú
B La Raya Experimental Center, Escuela Profesional Zootecnia, Universidad Nacional de San Antonio Abad del Cusco, Cusco, Perú
C College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
Reproduction, Fertility and Development 35(2) 213-214 https://doi.org/10.1071/RDv35n2Ab172
Published: 5 December 2022
© 2023 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the IETS
Seminiferous tubule maturation involves the proliferation and differentiation of Sertoli, Leydig, and spermatogonial cells from birth until puberty. In alpacas, data on testicular growth and maturation are scarce. Therefore, the aim of this study was to evaluate the morphometric parameters of alpaca testes in prepubertal and adult alpacas. Six prepubertal (6 to 12 months of age) and six postpubertal (24 and 36 months of age) Huacaya alpacas from the La Raya Experimental Center of Cusco located at more than 4,000 m of altitude were orchidectomised. The testes were separated from the epididymis, weighed, and cut longitudinally. Tissue samples measuring 5 × 5 × 3 mm were collected from testes then fixed (4% paraformaldehyde), embedded (paraffin), and sectioned (4 µm in thickness). Testicular tissue sections were stained with haematoxylin and eosin (HE), and periodic acid-Schiff-haematoxylin technique (PAS) and photographed using a HD IP camera (Carl Zeiss Microscopy GmbH) equipped with Zeiss Labscope software version 3.0. The volumetric ratios of seminiferous tubules and intertubule obtained by counting 2,048 points projected in eight fields were randomly chosen for each animal. The diameter (µm), perimeter (µm), and area (µm2) of the seminiferous tubules were determined in the same fields and scored at ×400 magnification. The image analysis was made with ImageJ® software (National Institutes of Health). Morphometric parameters were compared using ANOVA test. Testicular weight increased by ∼8-fold (1.51 to 12.18 g) between 12 to 24 months of age. The volumetric ratio of the seminiferous tubules doubled from 6 to 36 months of age (from 33.42 to 74.45%). The tubular diameter (µm) and tubular perimeter (µm) doubled in size from 12 to 24 months of age, in the first case from 44.04 to 99.70 µm, and the second from 162.57 to 329.01 µm; simultaneously, the tubular area increased 4-fold (1993.41 to 8644.14 µm2). In conclusion, testicular growth follows a sigmoidal growth curve, mostly due to growth in seminiferous tubule.
