Microbial diversity in the digestive tract of two different breeds of sheep

Selected bacteria in sheep stool depending on breed and physiology state

One of the important factors influencing the microbial community of ruminants, besides environment or diet, are breed and physiology. Therefore, the purpose of this study was to assess these changes in the levels of basic microbial phyla and families. For this study, qPCR analysis was performed to determine the level of bacteria (Firmicutes, Bacteroidetes, Actinobacteria, Proteobacteria clusters and Clostridiaceae, Lactobacillaceae families) in the feces of ewes of three native Polish sheep breeds (Polish Lowland Sheep (PON), Świniarka Sheep (SW), and synthetic line BCP) at different physiological periods (conception, early pregnancy, lambing, end of lactation). The animals were kept in the same environment and were at the same age (2-years). The results showed a significant effect of both breed (p = 0.038) and physiological period (p < 0.05, p < 0.01) on the levels of bacteria analyzed. The breed showed differences across physiological periods. The influence of the race factor was noted primarily between the BCP synthetic line and the other two breeds (differences in terms of all analyzed clusters and families except Actinobacteria phyla). In the case of SW and PON, however, the observed differences were only at the level of Proteobacteria cluster and Clostridiaceae family. On the other hand, the early pregnant and lambing periods were the most microbiologically diverse in terms of the analyzed clusters and families of bacteria.

Influence of selected factors on the Firmicutes, Bacteroidetes phyla and the Lactobacillaceae family in the digestive tract of sheep

In this study, we used 10 healthy sheep, which gave birth to healthy twins. Stool samples were collected from mothers and their offspring 3 times during the study (0, 28 and 56 day postpartum). Milk samples were taken from the mothers at the same time. RT PCR analysis of faeces and milk was performed in order to assess the level of bacteria from the Firmicutes and Bacteroidetes phyla including the family Lactobacillaceae (phylum Firmicutes). The composition of mother's milk was also analyzed and their BCS. The data were compiled statistically. The obtained results showed that the level of the studied groups of bacteria may change due to the change of diet. Additionally, there were significant differences between lambs and mothers in the levels of the studied groups of bacteria. Analysis also shown that in the digestive system of mothers was a smaller disproportion in the level of the studied bacterial phyla than in lambs. The results also indicated the occurrence of differences in the bacterial composition at the individual level, both in ewes and their offspring. Additionally, in the conducted experiment, there were differences in the level of Firmicutes and Bacteroidetes groups depending on the sex.

Evaluation of Changes in the Levels of Firmicutes and Bacteroidetes Phyla of Sheep Feces Depending on the Breed

Simple Summary

The microbiome plays an important role in the digestive system of ruminants. It affects the health status of animals and their development and production rates. However, its composition may be influenced by factors such as diet, age, gender, and health condition. The study was conducted on three breeds of sheep that were kept in one environment and fed with the same feed. The microbiological analysis showed that the animal microbiome is also influenced by breed.

Abstract

Studies carried out so far have indicated the effect of the microbiome on the composition of ruminant products. Recent studies have shown that not only diet, but also genetic factors can affect the microbiological composition of the digestive system. The aim of the study was to determine the differences in the levels of selected bacterial phyla in terms of breed differences. Three sheep breeds, i.e., Olkuska, Romanov, and old-type Polish Merino, differing in their use (meat–wool, meat, prolificacy) and country of breed origin were included in the study. Sheep at the same age and of the same sex were kept for a period of 3 months in the same environmental conditions and fed the same feed in the same proportions. The study included real-time PCR (polymerase chain reaction) analysis of feces collected before the slaughter and measurements of body weight and chilled carcasses. The obtained results showed significant differences between the breeds in the levels of bacterial populations tested. There were also differences in body weight between the breeds during the first weight measurements, however, the final results did not show any differences—after three months of maintenance all of them reached similar body weights, despite differences in fecal microbiological composition. The study suggests that in addition to diet and environmental conditions, the microbiology can also be influenced by breed.

The composition and stability of the faecal microbiota of Merino sheep

AIMS

To determine the composition and temporal stability of the gut (faecal) microbiota of sheep (Ovis aries).

METHODS AND RESULTS

Microbial population dynamics was conducted using ARISA (28 sheep) and 16S rRNA sequencing (11 sheep). Firmicutes and Bacteroidetes were the predominant bacterial phyla, constituting ~80% of the total population. The core faecal bacterial microbiota of sheep consisted of 67 of 136 detected families and 91 of 215 detected species. Predominant microbial taxa included Ruminococcaceae, unassigned families in Bacteroidales and Clostridiales, Verrucomicrobiaceae and Paraprevotellaceae. Diversity indices and core microbiota composition demonstrated the stability of the core microbiota over 2-4 weeks. The core microbiota remained similar over ~5 months.

CONCLUSIONS

Temporal stability of the sheep microbiota is high over 2-4 weeks in the absence of experimental variables. The core microbiota of Merino sheep shares taxa found in other breeds of sheep and other ruminants.

SIGNIFICANCE AND IMPACT OF THE STUDY

Numerous studies seek to investigate the impact of experimental variables on gut microbiota composition. To do so, knowledge of the innate stability (or instability) of the microbiota over an experimental time course is required, independent of other variables. We have demonstrated high stability of the gut microbiota in sheep over 3-4 weeks, with moderate stability over ~5 months.

Detection of the Bacteroides fragilis toxin gene in sheep with and without small intestinal adenocarcinoma

Aims: To determine if presence of the Bacteroides fragilis toxin (bft) gene, a molecular marker of colonic carriage of entertoxigenic Bacteroides fragilis (ETBF) in humans, was associated with a finding of small intestinal adenocarcinomas (SIA) in sheep in New Zealand. Methods: Samples of jejunal tissue were collected from the site of tumours and from grossly normal adjacent tissue in 20 sheep, in different consignments, diagnosed with SIA based on gross examination of viscera following slaughter. Two jejunal samples were also collected from a control sheep in the same consignment that had no gross evidence of SIA. A PCR assay was used to detect the presence of the bft gene in the samples. Results: Of the sheep with SIA, the bft gene was amplified from one or both samples from 7/20 (35%) sheep, and in sheep that had no gross evidence of SIA the bft gene was amplified from at least one sample in 11/20 (55%) sheep (RR 0.61; 95% CI = 0.30-1.25; p = 0.34). Of 11 positive samples analysed, ETBF subtype bft-1 was detected in one, bft-2 was detected in 10, and none were bft-3. Conclusions and Clinical Relevance: There was a high prevalence of detection of the bft gene in both SIA-affected and non-affected sheep, but there was no apparent association between carriage of ETBF, evidenced by detection of the bft gene, and the presence of SIA. ETBF are increasingly implicated in the aetiology of human colorectal cancer, raising the possibility that sheep may provide a zoonotic reservoir of this potentially carcinogenic bacterium. Abbreviation: Bft: Bacteroides fragilis toxin; ETBF: Enterotoxigenic Bacteroides fragilis; SIA: Small intestinal adenocarcinoma.

Rumen bacterial diversity of Tibetan sheep (Ovis aries) associated with different forage types on the Qinghai-Tibetan Plateau

Diet is the great determinant of bacterial composition in the rumen. However, little is known about the rumen bacterial community of Tibetan sheep living in the special ecological environment of the Qinghai-Tibetan Plateau (QTP) of China. In the present study, we used high-throughput sequencing to investigate the rumen bacterial community of Tibetan sheep associated with two primary diets: alpine pasture diet (a continuation of the sheep's natural grazing diet) and oat (Avena sativa) hay diet on the QTP. The results showed that bacterial community richness and species diversity of the oat hay diet group were significantly greater than that of the native pasture diet group (p < 0.05). Principal co-ordinate analysis and analysis of similarities revealed that the bacterial community of the oat hay diet group was distinctly different from that of the native pasture diet group (p < 0.05). Bacteroidetes and Firmicutes were the predominant microbial phyla in the rumen. The rumen of oat-hay-fed sheep had higher proportions of Proteobacteria and novel bacteria species than the rumen of native-pasture-fed sheep. Actinobacteria, an uncommon bacterial phylum, occurred only in the oat-hay-fed group. At the genus level, Komagataeibacter, Ruminococcaceae_UCG-014, and Ruminococcaceae_NK4A214 showed significantly higher relative abundance in the oat-hay-fed sheep than in the native-pasture-fed sheep (p < 0.05). This study is the first of the QTP to employ high-throughput sequencing to examine the influence of diet on the rumen microbiome of Tibetan sheep.