Daily sperm production and epididymal sperm reserves of pubertal and adult rats

TLDR

Puberty in rats begins at 50 days, marked by the first appearance of sperm in the epididymal tail. Sperm production increases until 75 days, testicular weight until 100 days, and epididymal reserves reach a maximum at 100 days, at which point sexually mature Wistar rats have 3.7 g testes, produce 86 × 10⁶ sperm/day (24 × 10⁶/g), and contain 295 × 10⁶ sperm in the head + body and 440 × 10⁶ in the tail.

Abstract

Rats were considered to be pubertal at 50 days of age when spermatozoa were first found in the tail of the epididymis. Sperm production/g testis increased up to 75 days of age and testicular weight increased until 100 days of age. Sperm reserves in the tail of the epididymis were not maximal until 100 days of age. Therefore, Wistar rats are not sexually mature until 100 days. Sexually mature rats had testes weighing 3.7 g, produced 86 x 10(6) spermatozoa or 24 x 10(6) spermatozoa/g testicular parenchyma daily, and their paired epididymides contained 295 x 10(6) spermatozoa in the head + body and 440 x 10(6) spermatozoa in the tail.