Comparison of the Gut Microbiota of Jeju and Thoroughbred Horses in Korea

Abstract

(1) Background: The large intestine of horses is an anaerobic fermentative chamber filled with fibrolytic bacteria that play essential roles in digesting and absorbing nutrients for energy production. Although Jeju horses are a prominent local breed in Korea, few studies have investigated the gut microbiota of Jeju horses; (2) Methods: This study performed sequencing of V3 and V4 hypervariable regions of the partial 16S rRNA genes obtained from horse fecal samples and compared the gut microbiota between Jeju and Thoroughbred horses. Thirty and 24 fecal samples were obtained from Jeju and Thoroughbred horses, respectively; (3) Results: The gut microbiota belonged to 23 phyla and 159 families. Firmicutes and Bacteroidetes were the most abundant and predominant phyla, followed by Verrucomicrobia, Euryachaeota, and Spirochaete. The ratio of Firmicutes to Bacteroidetes (F/B), which is known as a relevant marker of gut dysbiosis, was 1.84 for Jeju horses, whereas it was 1.76 for Thoroughbred horses. Moreover, at the genus level, 21 genera were significantly different between the Jeju and Thoroughbred horses (p < 0.05); (4) Conclusions: The Thoroughbred horse’s gut microbiotas had significantly higher diversity than the Jeju horses (p < 0.05). In addition, beneficial commensal bacteria that produce short-chain fatty acids thus providing a significant source of energy are also more abundant in Thoroughbred horses. These results provide novel information on the horse gut microbiota and insights for further studies related to the horse gut microbiota.

The diversity analysis and gene function prediction of intestinal bacteria in three equine species

“…Analysis of variance using one-way ANOVA on the composition of the intestinal bacterial community between species and analysis of the top five bacterial colonies with significantly different relative abundances showed that at the phylum level, no significantly different species were found in the intestinal bacteria of the three equine species ( P > 0.05). This result is in agreement with Park et al (2021) who compared the intestinal bacterial flora of Jeju and Thoroughbred horses in Korea. At the family level ( Figure 5A ), the relative abundance of Oscillospiraceae was highly significant higher at SP than at MA ( P < 0.01) and significantly higher at PZ ( P < 0.05); the relative abundance of Ruminococcaceae was significantly lower at PZ than at MA ( P < 0.05); norank_o_Clostridia_UCG-014 relative abundance was significantly higher in SP than PZ ( P < 0.05) but highly significant than MA ( P < 0.01); Erysipelotrichaceae relative abundance was highly significant higher in PZ than SP and MA ( P < 0.01); Selenomonadaceae relative abundance was significantly higher in SP and MA than PZ ( P < 0.05).…”

“…In addition, significant differences were found in the composition of the intestinal bacterial communities of different species. According to the study, significant differences were reported in the intestinal bacterial abundance index (Chao1) and diversity index (Shannon) between Korean Jeju horses and thoroughbred horses, in addition to significant differences in the structure of the intestinal bacterial flora between the two species by NMDS analysis ( Park et al, 2021 ). Therefore, we concluded that intestinal bacteria differ significantly among different species in the equine.…”

“…Current research on intestinal flora focuses on the analysis of microorganisms in feces and the determination of the composition of microorganisms in the intestine ( Zhu et al, 2021 ). Study of the intestinal microbiota of equine genera by traditional culture method has certain limitations ( Milinovich et al, 2006 ), as approximately 70% of the microbiota cannot be cultured in the laboratory, making it difficult to determine the entire microbial composition and largely limiting its application in taxonomy ( Julliand and Grimm, 2016 ; Park et al, 2021 ). The 16S ribosomal RNA (16S rRNA) gene high-throughput sequencing technology, as a novel technical tool for microbial diversity research, is now widely used in animal intestinal flora research, such as Illumina Hiseq-based technology to study different species ( Liu et al, 2020 ), age ( Xing et al, 2020 ), site ( Su et al, 2020 ), and other The structure and diversity of the intestinal microflora under the influence of different factors.…”

Variations in the fecal microbiota and their functions of Thoroughbred, Mongolian, and Hybrid horses

“…The 16S rRNA analysis of fecal microbiota from Mongolian and Thoroughbred horses living in Inner Mongolia (China) revealed that the relative abundance of 31.25% (5/16) phyla and 40% (30/75) genera was significantly different between the two breeds ( 14 ). Another study showed that Thoroughbred horses had higher gut microbiota diversity than Jeju horses in Korea ( 15 ). Moreover, the abundance of beneficial commensal bacteria (Lachnospiraceae, Oscillibacter , Clostridium_XIVa, etc.)…”

“…Moreover, the abundance of beneficial commensal bacteria (Lachnospiraceae, Oscillibacter , Clostridium_XIVa, etc.) that produce SCFAs to supply the host with more energy sources was also higher in Thoroughbred horses than in Jeju horses ( 15 ). When comparing the differences in gut microbiota among six horse breeds in a study by Massacci et al, 27 genera were found significantly different among breeds ( 16 ).…”