İstilacı Mikrobiyal Enfeksiyon ve Tedavi Sonucu Koyun Bağırsak Mikrobiyomundaki Tür Bileşimi Değişiklikleri

Tez Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Yıldız Teknik Üniversitesi, İskoçya

Tez Danışmanı: Dr. Andrew Free (The University Of Edinburgh)

Tezin Onay Tarihi: 2014

Tezin Dili: İngilizce

Desteklendiği Program: Diğer

Özet:

An animal’s gastrointestinal system harbours a vast and diverse microbial community that directly contributes to the host health and welfare. Although the profound impact of the gut microbiota on health is undeniable, there is still limited knowledge about the gut microbiota of commercially important livestock animals and ways they change following parasitic infections. In this study, ovine gut microbiota from three sheep experimental groups were analysed. Microbial diversity differences between the ileum and rectum were analysed from the first group of sheep. The second group was infected with drug resistant and drug sensitive strains of the nematode Teladorsagia circumcincta and then either treated with the anti-parasite drug, monepentel, or left untreated. The impact of nematode infection and treatment on the gut microbial community was investigated with the samples that were collected from this second sheep group. The third group were farm bred sheep where half of the individuals were diagnosed with Johne’s disease. Alterations in the gut microbiome resulting from enteric bacterial infections were investigated for this third group.

The bacterial community of the gastrointestinal microbiota was studied by sequencing of the 16S rRNA gene V4 region amplicons using the Illumina sequencing platform. Sequence data was analysed with the Quantitative Insights Into Microbial Ecology (QIIME) tool where taxonomy was assigned to the sequencing reads and alpha diversity of the samples was measured. Multivariate analysis of the data was performed using PERMANOVA and PERMDISP statistical tests. Archaeal diversity was evaluated using the Denaturing Gradient Gel Electrophoresis (DGGE) fingerprinting technique.

Our results suggest that the bacterial diversity of ovine gut microbiota was found to be more diverse than archaeal microbiota. It was also found that the microbiota from the colon and small intestine are significantly different and that the colon microbiota is more diverse than the ileal microbiota. The gut microbiota that was exposed to nematode infection and drug treatment factors appeared quite similar in taxonomic assignment but significant differences at the Operational Taxonomic Unit (OTU) level were detectable. Further, it was found that in cases of serious Johne’s disease, symptoms such as diarrhoea exert drastic impacts on the microbial communities of the gut.