Oregano Essential Oils Mediated Intestinal Microbiota and Metabolites and Improved Growth Performance and Intestinal Barrier Function in Sheep

Abstract

With the increased demand for safe and sustainable alternatives to growth promoting antibiotics in the livestock industry, oregano essential oils (OEO) and Lactobacillus reuteri (LR) have been examined as alternatives to antibiotics for growth promotion and to improve animal health and performance. However, the mechanism underlying the OEO and LR mediation of sheep growth remains unknown. In this study, 16S rRNA gene sequencing and untargeted metabolomics were used to determine the role of the gut microbiota in the growth improvements observed. The potential modulating roles of intestinal microbial metabolites of OEO and LR to intestinal health were systematically explored as well. It was observed that both OEO and LR had greater average daily gain (ADG) and lower F/G ratio. Furthermore, OEO also appeared to have produced a greater amylase enzyme activity and mucin gene expression in the jejunal mucosa. It was also observed that OEO reduced serum IL-2 and TNF-β as well as mRNA levels of NF-κB p65, toll-like receptor-4 (TLR-4), and IL-6 in the jejunal mucosa. Moreover, dietary OEO supplementation increased the abundances of Ruminococcus, Bifidobacterium and Enterococcus, while the relative abundances of Succiniclasticum, Marvinbryantia and Streptococcus were enriched in LR group. Spearman’s correlation analysis revealed that the abundances of Bifidobacterium, Ruminococcus and Enterococcus were positively correlated with the mRNA expression of mucins. Moreover, the relative abundance of Enterococcus was positively correlated with amylase activity. Metabolomics analysis indicated that OEO and LR increased the levels of indole acetaldehyde and indole-3-acetic acid through the tryptophan metabolism pathway. It was observed that LR also decreased the inflammatory metabolites including tryptamine and 5-hydroxyindole-3-acetic acid. Collectively, these results suggested that OEO exerted a beneficial effect on growth performance and the mucosal barrier, affected tryptophan metabolism and improved the intestinal microbiota of sheep.

The ileal microbiome and mucosal immune profiles in response to dietary supplementation of ultra-grinded Astragalus membranaceus in weaned goats

“…In the present study, Firmicutes was the predominant phylum, succeeded by Verrucomicrobiota , Proteobacteria , and Bacteroidetes , which is consistent with the report by Jia et al (2022) that Firmicutes , Actinobacteria , Verrucomicrobia , and Bacterioidetes constituted the predominant phyla in the goat ileum. Dietary supplementation of UGAM altered the taxonomic composition of ileal microbiota, with notable reductions in the relative abundances of Verrucomicrobiota at the phylum level and Mycoplasma at the genus level in the present study.…”

Oregano essential oil modulates colonic homeostasis and intestinal barrier function in fattening bulls

“…This results in enhanced weight gain in cattle, translating into greater earnings and more economic benefits. Moreover, OEO can modulate sheep’s small intestine microbiota to promote growth ( Jia et al, 2022 ). Furthermore, OEO can replace antibiotics in lamb diets, positively impacting meat quality ( Garcia-Galicia et al, 2020 ).…”

Essential Oil Supplementation in Small Ruminants: A Review on Their Possible Role in Rumen Fermentation, Microbiota, and Animal Production

“…A decrease in potentially pathogenic genera such Streptococcus, Escherichia, and Clostridium was measured with a concomitant decrease in the population of Bifidobacterium in the jejunum and cecum. The addition of oregano essential oil (52 mg/head/day) in the diet of small-tailed Han × Hu female lambs resulted in an increased average daily gain and a decrease in the feed/gain (F/G) ratio [73]. The authors observed that dietary supplementation with oregano EO promoted the enrichment in intestinal microbiota of Ruminococcus, Bifidobacterium, and Enterococcus, with the increase in the levels of indole-3-acetic acid and indole acetaldehyde.…”