Bacterial communities in the gastrointestinal tract segments of helminth-resistant and helminth-susceptible sheep

Abstract

Background Helminth parasitism is a world-wide problem in livestock industries, with major impacts on health, welfare and productivity. The role of the gut microbiota in host-helminth interactions in ruminants has been extensively examined and the present study added to this body of knowledge by assessing the effects of resistance and susceptibility to helminth infection in the gastro-intestinal tract (GIT). Australian Sheep Breeding Values (ASBVs) for faecal egg count (FEC) were used to select the 10 highly helminth-susceptible (High-FEC) and 10 highly helminth-resistant (Low-FEC) sheep. FEC status was confirmed during the experiment. Using samples from the faeces and the lumen of the rumen, abomasum, duodenum, jejunum, ileum, caecum, and colon, DNA was extracted and used for 16 rRNA gene amplicon sequencing. Results The most frequent genera identified along the GIT were Eubacterium, Oscillibacter, and Ruminococcus. Intersectoral-specialization zones were identified along the GIT, with the duodenum displaying major differences between the High-FEC and Low-FEC animals in values for alpha and beta diversity. After taking all samples into account and adjusting for GIT segment, the High-FEC and Low-FEC sheep differed significantly for four genera Butyrivibrio, Mycoplasma, Lachnoclostridium and Succiniclasticum. In the duodenum, the abundances of Aminipila, Lachnoclostridium and Mogibacterium differed significantly between the High-FEC and Low-FEC sheep. In the ileum, on the other hand, the genus Mycoplasma was significantly depleted in the Low-FEC group. Conclusions The gastro-intestinal microbial profile varies widely between helminth-resistant and helminth-susceptible sheep. Each GIT section appears to support a particular bacterial composition leading to inter-sectoral differences among the various microbial communities. The microbial populations were most rich and diverse in the duodenum of helminth-resistant sheep, comprising bacterial genera that generally ferment carbohydrates. This observation suggests that helminth-resistant sheep can reorganize the duodenal microbiome taxa which may restrict the development of parasites.

The Gut Microbiome of an Indigenous Agropastoralist Population in a Remote Area of Colombia with High Rates of Gastrointestinal Infections and Dysbiosis

“…Finally, Parabacteroides , Prevotella , and Butyrivibrio were associated with salmonellosis, EPEC, and helminth infections. Of note, similar observations have been reported previously, both from epidemiological assessments and experimental veterinary medical assessments [ 61 , 62 , 63 , 64 , 65 ]. Such coincidences in the literature confirm the findings of the assessments presented here, although potential causal relations are still largely unknown.…”

Interaction between bacterial microbiota and nematode parasite communities in sheep’s gastrointestinal tract

“…However, taking into account that there is no direct evidence that MNP may have some activity against mycoplasma, we can hypothesize that the lack of parasites may prevent abomasum colonization by microbes of the Mycoplasmataceae family. In this sense, Paz et al, (2022) [ 38 ] reported that the whole GI tract of sheep with low epg counts had lower Mycoplasma abundance than sheep with high epg counts. The use of a limited number of animals is a constraint of the experimental design used in this research.…”

“…Unlike Mycoplasmataceae , the family Methanobacteriaceae , whose relative abundance in sheep abomasum was 1.89, was increased in 3 out of 5 dewormed animals. Considering that methanobacteria are usually identified in the rumen but not in the abomasum of sheep [ 38 ], we believe that this family isolated from the abomasum would actually come down from the rumen of treated sheep. Methanobacteria can pass from the rumen to the abomasum in sheep through a narrow passage called the reticulum-omasal orifice; this passage is normally closed, but it can open to allow food and fluid to pass from the rumen to the abomasum [ 39 ].…”

Short Term Effect of Ivermectin on the Bacterial Microbiota from Fecal Samples in Chinchillas (Chinchilla lanigera)

“…Oscillibacter is a common genus in herbivores and may assist in plant polysaccharide utilization [ 16 ], was identified on day 0. Some articles showed that Oscillibacter contained beneficial bacteria, of which the metabolites like butyric acid and alpha-linolenic acid can resist inflammation and protect intestinal mucosa [ 29 , 30 ]. Speculating effects of ivermectin on these genera may affect the intestinal microbiota balance and change the fiber metabolism, which reduces the protective function of normal microbiota.…”