Metabolism of fowl and turkey spermatozoa at low temperatures.

The rate at which fowl and turkey spermatozoa consumed energy (as ATP) in a glutamate-based medium without glucose decreased with temperature by 75-80% over the range 40 to 5 degrees C. The rate of oxygen utilization of these spermatozoa, as a monitor of their rate of energy production, also decreased by 75-80% over the same range of temperature, although sperm ATP levels remained constant. The rate of glycolysis of fowl spermatozoa decreased by a factor of 20 between 40 and 5 degrees C but remained capable of supporting optimal sperm ATP levels. Turkey sperm glycolysis proceeded extremely slowly and was not capable of supporting optimal ATP levels at any temperature investigated. Turkey, but not fowl spermatozoa, therefore require oxygen to maintain optimal energy levels at all temperatures between 5 and 40 degrees C.