Polyomic tools for an emerging livestock parasite, the rumen fluke Calicophoron daubneyi; identifying shifts in rumen functionality

Abstract

BackgroundDiseases caused by parasitic flatworms of rumen tissues (paramphistomosis) are a significant threat to global food security as a cause of morbidity and mortality in ruminant livestock in subtropical and tropical climates. Calicophoron daubneyi is currently the only paramphistome species commonly infecting ruminant livestock in temperate European climates. However, recorded incidences of C. daubneyi infection in European livestock have been increasing over the last decade. Whilst clinical paramphistomosis caused by adult worms has not been confirmed in Europe, fatalities have been attributed to severe haemorrhagic enteritis of the small intestine resulting from the migration of immature paramphistomes. Large numbers of mature adults can reside in the rumen, yet to date, the impact on rumen fermentation, and consequently on productivity and economic management of infected livestock, have not been resolved. Limited publicly available nucleotide and protein sequences for C. daubneyi underpin this lack of biological and economic understanding. Here we present for the first time a de novo assembled transcriptome, with functional annotations, for adult C. daubneyi, which provides a reference database for protein and nucleotide sequence identification to facilitate fundamental biology, anthelmintic, vaccine and diagnostics discoveries.ResultsThis dataset identifies a number of genes potentially unique to C. daubneyi and, by comparison to an existing transcriptome for the related Paramphistomum cervi, identifies novel genes which may be unique to the paramphistome group of platyhelminthes. Additionally, we present the first coverage of the excretory/secretory and soluble somatic proteome profiles for adult C. daubneyi and identify the release of extracellular vesicles from adult C. daubneyi parasites during in vitro, ex-host culture. Finally, we have performed the first analysis of rumen fluke impacting upon rumen fermentation parameters using an in vitro gas production study resulting in a significant increase in propionate production.ConclusionsThe resulting data provide a discovery platform (transcriptome, proteomes, EV isolation pipeline and in vitro fermentation system) to further study C. daubneyi-host interaction. In addition, the acetate: propionate ratio has been demonstrated to decrease with rumen fluke infection suggesting that acidotic conditions in the rumen may occur.Electronic supplementary materialThe online version of this article (10.1186/s13071-018-3225-6) contains supplementary material, which is available to authorized users.

Modulation of Rumen Microbes Through Extracellular Vesicle Released by the Rumen Fluke Calicophoron daubneyi

“…matrixofscience.com) was used for analysis by carrying out an MS/MS ion search, settings were set for the enzyme trypsinallowing 2 missed cleavages, with a fixed modification of carbamidomethyl (C) and a variable modification of oxidation (M) with a peptide charge of 2+, 3+ and 4+. Each sample was then searched against an in-house database composed of a transcript for C. daubneyi (Huson et al, 2018) available to search at https:// sequenceserver.ibers.aber.ac.uk/. Each of the contigs returned were then searched within an in-house copy of the transcript and the nucleotide sequence recorded.…”

“…Paramphistomes, commonly known as rumen fluke, have been found to infect ruminant animals worldwide (Huson et al, 2017;Huson et al, 2018). Within tropical and sub-tropical regions, rumen fluke infections cause significant production losses; yet only in recent years have rumen fluke infections been observed throughout Europe with the major species responsible confirmed as Calicophoron daubneyi (Sanabria and Romero, 2008;Jones et al, 2017).…”

“…EVs have been confirmed to be released from the rumen fluke C. daubneyi (Huson et al, 2018). However, these EVs are yet to be studied at a molecular level or in relation to their effects on rumenal microbes.…”

Transcriptome and Secretome Analysis of Intra-Mammalian Life-Stages of Calicophoron daubneyi Reveals Adaptation to a Unique Host Environment

“…This revealed that HDM transcripts were more highly expressed in the NEJ and immature stages Table S3). Of these, 272 proteins were unique to the Transcriptome data is currently available for two paramphistome species, Paramphistomum cervi and C. daubneyi (53,54). However, these studies have been limited to the adult life-cycle stage which are often described as "well-tolerated" by their ruminant hosts since they are responsible for chronic paramphistomosis which is largely subclinical (13).…”

Parasitic gastroenteritis and pasteurellosis dominate Scottish surveillance diagnoses

“…Nonetheless, acute disease can cause high mortality in both sheep and cattle;3,4 histopathology has demonstrated a localised inflammatory response at the site of attachment in the rumen;5 and in vitro models suggest that the presence of adult flukes may alter ruminal volatile fatty acid production 6…”