Taxonomia, ecologia e filogenia de ciliados (alveolata, ciliophora) endossimbiontes de mamíferos herbívoros

Abstract

Approximately 250 species of rumen ciliates have been described since 1843, when Gruby and Delafond found microorganisms living symbiotically with ruminant and pseudoruminant hosts. These microorganisms play important roles, from the degradation of fibers to the maintenance of the rumen microbial balance. However, knowledge about this eukaryotic group remains little understood, especially for hosts such as goats and remote regions such as Mozambique, thus, the aim of this thesis was to comprehend morphology, taxonomy, phylogeny and the relationships of endosymbiont ciliate protozoans of herbivorous mammals via an integrative approach of morphological, ecological, phylogenetic and molecular analyses. This work is organized into four chapters, beyond that, we make a quick review of some of the theoretical foundations for rumen ciliates since their discovery, characteristics of rumen ciliates, their hosts, their importance, and main techniques and methods used in studies about them. In the first chapter is presented in which we have a checklist of rumen ciliate species associated with caprines, their geographic distribution, host specificity, and some macro-evolutive aspects of the species. In the second chapter we analyze the generic and specific composition of ciliate protozoans in the rumen of the Landim goat breed, from northern Mozambique, but we also compare generic and specific density with records from other studies. Still within the second chapter, we compile records of ciliates in domestic ruminants from African countries. In the third chapter we used the ITS marker in order to analyze the phylogenetic relationships of some representative species of rumen ciliates. Within this third chapter, we demonstrate that the use of a concatenated dataset between the 18S genes and the ITS region may be a valid alternative to infer the phylogenetic relationsships between the taxa of rumen ciliates. In the fourth chapter we used Illumina 18S rRNA sequencing to characterize the successive establishment of the rumen ciliate community in Dutch x Gir F1 calves. This thesis may contribute to a better understanding of some aspects related to morphology, taxonomy, phylogeny, and ecological of rumen ciliates from ruminant herbivores.