Search

With an increasing human population access to ruminant products is an important factor in global food supply. While ruminants contribute to climate change, climate change could also affect ruminant production. Here we investigated how the plant response to climate change affects forage quality and subsequent rumen fermentation. Models of near future climate change (2050) predict increases in temperature, CO2, precipitation and altered weather systems which will produce stress responses in field crops. We hypothesised that pre-exposure to altered climate conditions causes compositional changes and also primes plant cells such that their post-ingestion metabolic response to the rumen is altered. This “stress memory” effect was investigated by screening ten forage grass varieties in five differing climate scenarios, including current climate (2020), future climate (2050), or future climate plus flooding, drought or heat shock. While varietal differences in fermentation were detected in terms of gas production, there was little effect of elevated temperature or CO2 compared with controls (2020). All varieties consistently showed decreased digestibility linked to decreased methane production as a result of drought or an acute flood treatment. These results indicate that efforts to breed future forage varieties should target tolerance of acute stress rather than long term climate.

The rumen is a complex ecosystem. It is the primary site for microbial fermentation of ingested feed allowing conversion of a low nutritional feed source into high quality meat and milk products. However, digestive inefficiencies lead to production of high amounts of environmental pollutants; methane and nitrogenous waste. These inefficiencies could be overcome by development of forages which better match the requirements of the rumen microbial population. Although challenging, the application of meta-proteomics has potential for a more complete understanding of the rumen ecosystem than sequencing approaches alone. Here, we have implemented a meta-proteomic approach to determine the association between taxonomies of microbial sources of the most abundant proteins in the rumens of forage-fed dairy cows, with taxonomic abundances typical of those previously described by metagenomics. Reproducible proteome profiles were generated from rumen samples. The most highly abundant taxonomic phyla in the proteome were Bacteriodetes, Firmicutes and Proteobacteria, which corresponded with the most abundant taxonomic phyla determined from 16S rRNA studies. Meta-proteome data indicated differentiation between metabolic pathways of the most abundant phyla, which is in agreement with the concept of diversified niches within the rumen microbiota.

The mechanisms involved in anthelmintic resistance (AR) are complex but a greater understanding of AR management is essential for effective and sustainable control of parasitic helminth worms in livestock. Current tests to measure AR are time consuming and can be technically problematic, gold standard diagnostics are therefore urgently required to assist in combatting the threat from drug resistant parasites. For anthelmintics such as ivermectin (IVM), target proteins may be present in the cellular membrane. As proteins usually act in complexes and not in isolation, AR may develop and be measurable in the target associated proteins present in the parasite membrane. The model nematode Caenorhabditis elegans was used to develop a sub-proteomic assay to measure protein expression differences, between IVM resistant and IVM susceptible isolates in the presence and absence of drug challenge. Evaluation of detergents including CHAPS, ASB-14, C7BzO, Triton ×100 and TBP (tributyl phosphine) determined optimal conditions for the resolution of membrane proteins in Two Dimensional Gel Electrophoresis (2DE). These sub-proteomic methodologies were then translated and evaluated using IVM-susceptible and IVM-resistant Haemonchus contortus; a pathogenic blood feeding parasitic nematode which is of global importance in livestock health, welfare and productivity. We have demonstrated the successful resolution of membrane associated proteins from both C. elegans and H. contortus isolates, using a combination of CHAPS and the zwitterionic amphiphilic surfactant ASB-14 to further support the detection of markers for AR.

The parasitic flatworm Fasciola hepatica is a global food security risk. With no vaccines, the sustainability of triclabendazole (TCBZ) is threatened by emerging resistance. F. hepatica excretory/secretory (ES) products can be detected in host faeces and used to estimate TCBZ success and failure. However, there are no faecal based molecular diagnostics dedicated to assessing drug failure or resistance to TCBZ in the field. Utilising in vitro maintenance and sub-proteomic approaches two TCBZ stress ES protein response fingerprints were identified: markers of non-killing and lethal doses. This study provides candidate protein/peptide biomarkers to validate for detection of TCBZ failure and resistance.