Respiratory Physiology of Fish, Amphibian, and Mammalian Sperm

Abstract

Teleost (Liza dumerili) and toad (Xenopus laevis) sperm consume oxygen optimally at high oxygen tensions (120–150 mm Hg) close to the saturation level of the diluents. Oxygen consumption of sperm of both species declines rapidly below a pO₂ of 60 mm Hg. Sperm of both species consume more oxygen per unit sperm in dilute than in dense sperm suspensions and conform to the so-called respiratory dilution effect. In contrast, ram sperm do not conform to the respiratory dilution effect and utilize oxygen with the same efficiency over a pO₂ range of 4–130 mm Hg. Sperm respiration over this range of oxygen tensions was therefore linear and averaged 19 μ10₂ ± 10⁻⁸ sperm ± h⁻¹.