title: A cryopreservation procedure for the rumen protozoon Entodinium caudatum: estimation of its viability by fluorescence microscopy.
abstract: OBJECTIVE
  To study the viability of a culture of the rumen protozoon Entodinium caudatum after a cryopreservation procedure by a fluorescence microscopy staining method.
  
  
  RESULTS
  Fluorescence method is based on the different colour of cells depending on their membrane integrity. When the temperature effect was studied either by fluorescence or motility, the techniques were correlated (r = 0.727) and their slopes and intercepts were not different (P > 0.05). However, motility showed a higher variation coefficient (0.40 vs 0.12). There were no differences between cooling rates at cryopreservation (1 and 4 degrees C min-1) at 38, 15 or 5 degrees C, nor after thawing.
  
  
  CONCLUSIONS
  Fluorescence staining is more accurate than motility for assessing protozoal viability. Viability after thawing was 0.50, and the number of viable cells per 250 microl straw was 320 and 420 for 1 and 4 degrees C min-1.
  
  
  CONCLUSIONS
  This cryopreservation procedure seems to ensure culture recovery for E. caudatum.
authors.affiliation: Departamentos de Producción Animal y Ciencia de los Alimentos Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain.
authors.forename: G
authors.initials: G
authors.lastname: de la Fuente
authors.forename: J A
authors.initials: JA
authors.lastname: Cebrián
authors.forename: M
authors.initials: M
authors.lastname: Fondevila
mesh_terms: D000818:Animals; D002463:Cell Membrane Permeability; D016798:Ciliophora / Q000502:physiology*; D015925:Cryopreservation / Q000379:methods*; D005615:Freezing; D008856:Microscopy, Fluorescence; D009068:Movement; D012417:Rumen / Q000469:parasitology; D013194:Staining and Labeling; D013696:Temperature