Single-layer centrifugation with Androcoll-E can be scaled up to allow large volumes of stallion ejaculate to be processed easily

J.M. Morrell, A. Johannisson, A.-M. Dalin, H. Rodriguez-Martinez

The objective of the current study was to optimize the volumes of Androcoll-E and sperm sample used in various sizes of centrifuge tube to scale up single-layer centrifugation (SLC) for routine use in the field. Although sperm suspensions of equivalent quality were produced using Androcoll-E in small and large tubes, the sperm yield was much lower in the latter (P<0.001). In contrast, in 200-mL tubes (XL), the yields were approximately 25% higher than those for the small tubes. An increased volume (4.5 mL) of extended ejaculate in small tubes (SLC-Inc) or 15 to 18 mL extended ejaculate on 15 mL of colloid of a reduced density, Androcoll-E-Large (SLC-Large), in 50-mL tubes were both found to give similar yields of motile spermatozoa as that of the SLC-Small method (SLC-Small, 49.7+/-18.6%; SLC-Inc, 53.3+/-17.1%; SLC-Large, 44.9+/-18.3%) and were found to be equivalent in quality (motility: 88.0+/-8.8%, 84.0+/-3.5%, 90.0+/-5.4%; normal morphology: 69.4+/-17.0%, 69.4+/-12.7%, 63.9+/-15.6%; viability: 78+/-16.7%, 83.8+/-12.5%, 80.05+/-14.6%; DNA fragmentation index: 14.7+/-10.9%, 12.8+/-8.1%, 11.6+/-7.6%, respectively). The processing of an "average" stallion Equus caballus ejaculate in approximately twenty-seven 10-mL tubes (SLC-Inc) or eight 50-mL tubes (SLC-Large) is feasible, the latter being considered more practical for on-stud use.