A fluorometric-reflectometric technique for simultaneous measurement of pH and motility in ram semen

An optical technique for simultaneous assessment of pH and motility in ram semen was described. Motility was evaluated by the measurement of changes in intensity of reflected light from semen samples illuminated with 366 nm light. pH was measured by using a pH-sensitive fluorescent indicator (umbelliferone). From the changes in fluorescence intensity (450 nm) as a function of the pH of the semen, a calibration curve was constructed. The relationship between pH changes and motility in various metabolic conditions were described. Different kinetics for pH changes occurred when sperm motility was driven by both mitochondrial respiration and fructolysis or by either one of them. An analysis of the fluorescence signal from extracellular or cellular fractions of semen suggested that the pH measurement reflected extracellular pH.