Effects of Egg Yolk-Citrate and Milk Extenders on Chromatin Structure and Viability of Cryopreserved Bull Sperm

• Published in: Journal of dairy science 1991-11, Vol.74 (11), p.3836-3848
• Main Authors: Karabinus, D.S., Evenson, D.P., Kaproth, M.T.
• Format: Article
• Language: English
• Subjects: Analysis of Variance; Animals; Biological and medical sciences; BOVIN LAITIER; bull; Cattle - physiology; Cell Membrane - drug effects; Cell Membrane - ultrastructure; Chromatin - drug effects; Chromatin - ultrastructure; Citrates - pharmacology; CONGELACION; CONGELATION; CONSERVACION DEL SEMEN; CONSERVATION DU SPERME; Cryopreservation; Egg Yolk - chemistry; ESPERMATOZOO; extender; Flow Cytometry; Fundamental and applied biological sciences. Psychology; GANADO DE LECHE; General aspects; LAIT; LECHE; Male; Milk - physiology; PRESERVACION; PRESERVATION; RACE; RAZAS; SEMEN; Semen Preservation; semen quality; Sperm Motility; Spermatozoa - drug effects; Spermatozoa - physiology; Spermatozoa - ultrastructure; SPERMATOZOIDE; SPERME; Staining and Labeling; TAUREAU; TORO; Vertebrates: anatomy and physiology, studies on body, several organs or systems; VITELLUS; YEMA DE HUEVO
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.S0022-0302(91)78576-7

Semen from four Holstein bulls was evaluated to compare effects of four extender treatments on postthaw semen quality. Extender fractions A and B, either heated whole milk or 20% egg yolk-citrate, were combined to yield the extender treatments 1) milk and milk, 2) milk and egg yolk-citrate, 3) egg yolk-citrate and milk, and 4) egg yolk-citrate and egg yolk-citrate. Semen was evaluated at thawing and after 30, 60, 120, and 180min of incubation at 38.5°C. How cytometry showed that acridine orange-stained sperm were most susceptible to in situ DNA denaturation when fraction A was milk. For sperm stained with rhodamine 123, flow cytometry showed that the proportion with intact mitochondrial membrane potential was lowest of all treatments at thawing but greatest at 180-min incubation with milk and milk extender. Flow cytometry of propidium iodine-stained sperm showed greatest proportion of cell membrane intact sperm when fraction A was egg yolk-citrate. Light microscopy showed the lowest proportion of cell membrane intact sperm with milk and milk extender after eosin-aniline blue vital staining. Postthaw motility scores tended to be reduced when both extender fractions were egg yolk-citrate. Results demonstrate differential extender effects on postthaw semen quality and indicate that altering extender composition or sequence of adding extender components may improve postthaw quality of cryopreserved sperm.