Improved silver carbonate impregnation method for rumen ciliate protozoa

Resumo

This study proposes improvements to the pyridinated silver carbonate impregnation technique in rumen ciliate protozoa in order to provide a standardized impregnation protocol for usable for the largest possible number of species in domestic ruminants. The proposed improvements are based on results obtained from impregnation of oral infraciliature and nuclear apparatus of 36 rumen ciliate species, which are symbionts of domestic ruminants. Compared to established protocols for morphology of rumen ciliates, impregnation of a wider range of genera and species was observed with the proposed protocol. The impregnation time varied according to size, ciliate taxon, or both, varying from shorter (5 minutes) for small entodiniomorphid ciliates (<80 μm) and the genus Dasytricha, to longer (30 minutes) for large entodiniomorphid ciliates (>80 μm) and the genus Isotricha. The proposed protocol is simple and easily reproducible. It is also advantageous for taxonomic, animal science, and ecological studies that aim to inventory the ruminal biota as well as understand the population structure of rumen ciliates and their relationship with the host.