Effect of season on structural composition of drake testes and daily spermatozoa production as determined by quantitative testicular histology

Abstract

Seasonal effects on the structural features of drake testes and daily spermatozoa production were investigated by a light microscopy technique, as well as morphometric and quantitative histological procedures. The present study is aimed at understanding the effects of different seasons on the reproductive potential of drakes. The results showed that the volume of the testes occupied by seminiferous tubules was similar (P>0.05) in all the seasons studied. However, the relative percentage of the primary spermatocytes, spermatids, spermatozoa, epithelial height, lumen diameter, and Leydig cells were significantly higher (p<0.05) during the early and late rainy seasons compared to the early and late dry seasons. The daily sperm production per testis in the early rainy season, late rainy season, early dry season, and late dry season were 0.86 × 109± 1.30, 0.84 × 109± 1.20, 0.54 × 109± 1.13 and 0.52 × 109± 1.17, respectively. The daily sperm productions per testis and per gram of testes were significantly higher (p<0.05) during the early rainy season compared to the early and late dry seasons, respectively. All the micrographs examined, showed evidence of normal spermatogenesis throughout the year. The findings in the present study indicate that drakes in the tropical environment (south-eastern Nigeria) are capable of breeding throughout the year; however, sperm production efficiency is optimal during the early rainy season.