Submitted to: Government Publication/Report
Publication Type: Government Publication
Publication Acceptance Date: 5/9/2015
Publication Date: 5/9/2015
Citation: Li, R.W. 2015. The caprine abomasal microbiome. Government Publication/Report. Accession Numbers# 4629311.3-4629350.3.
Technical Abstract: Parasitism is considered the number one health problem in small ruminants. The barber's pole worm Haemonchus contortus infection in goats elicits a strong host immune response. However, the effect of the parasitic infection on the structure and function of the gut microbiome remains largely unknown. In this study, we characterized the impact of helminth infection on the caprine abomasal microbiome using deep Illumina sequencing and bioinformatics tools. Fourteen parasite-naive young goats were exposed to 5,000 drug-resistant L3 larvae of H. contortus for 50 days. Six age-matched naïve goats served as uninfected controls. Compared to the naive controls, the infection resulted in a reduced bodyweight gain and a significant increase in the abosamal pH values (P <0.05). Sequencing of hyper-variable V3 to V4 regions of the 16S rRNA genes (the mean number of 2x250bp paired-end sequence reads = 226,179, N=20) identified 520 species-level operational taxonomic units (OTU) per sample (mean +- SD = 520 +- 74.7) while 84 OTU were common to all samples tested and likely represented the core caprine abomasal microbiome. The infection increased bacterial load while reducing the abundance of Arachea in the abomasum. The infection did not appear to affect a diversity indices. Nevertheless, the infection altered abundance of approximately 25.4% of OTU detected (P <0.05). A total of 67 taxa displayed a significantly different abundance between control and infected groups (absolute Linear Discriminant Analysis LDA score log10 >= 3.0), including 17 species-level OTU. Furthermore, the infection appeared to result in a distinct difference in the microbiome structure between the control and infected groups. The elevated abundance levels of Prevotella in infected animals may have implications for impairing host protein metabolism. Moreover, we hypothesize that the parasitic infection may modulate butyrate biosynthesis in the hindgut, which plays a critical role in regulating tissue inflammation. The pathophysiolocal relevance of the changes in the abomasal microbiome induced by helminth infection is also discussed. Our results provide novel insights into physiological consequences of the infection, which should facilitate development of novel strategies for helminth control in animals and humans.