This study aimed to explore the effects of oregano essential oils (OEO) on the rumen digestive ability using multi-omics sequencing techniques. Twenty-seven castrated Pingliang red cattle were randomly separated into three groups (3 cattle/pen; n = 9) and fed on a daily basal diet supplemented with 0 (Con group), 130 mg (L group), and 260 mg (H group) OEO. The finishing trial lasted for 390 days, and all cattle were slaughtered to collect rumen tissue and content samples. We found that the rumen papillae length in the H group was higher than in the Con group. Amylase concentrations were decreased in the H group than the Con group, whereas the β-glucosidase and cellulase concentrations increased. Compared to the Con group, the relative abundance of propionate and butyrate in the H group was significantly higher. Higher relative abundance of Parabacteroides distasonis and Bacteroides thetaiotaomicron were observed with increasing OEO concentration. The function of rumen microbiota was enriched in the GH43_17 family, mainly encoding xylanase. Besides, metabolites, including heparin, pantetheine, sorbic acid, aspirin, and farnesene concentrations increased with increasing OEO dose. A positive correlation was observed between Parabacteroides distasonis, Bacteroides thetaiotaomicron, and β-glucosidase, cellulase and propionate. The abundance of Parabacteroides distasonis and Parabacteroides_sp._CAG:409 were positively correlated with sorbic acid and farnesene. In summary, OEO supplementation increased the rumen digestive ability by modulating epithelial development and microbiota composition in beef cattle. This study provides a comprehensive insight into the OEO application as an alternative strategy to improve ruminant health production.

This study was conducted to elucidate the effects of oregano essential oil (OEO) supplementation on the meat quality, antioxidant capacity, and nutritional value of the longissimus thoracis muscle in steers. Steers were divided into three groups (n = 9) and fed either a basal diet, or a basal diet supplemented with 130 mg/d OEO, or 230 mg/d OEO for 390 days. The results demonstrated that dietary OEO supplementation increased the total antioxidant capacity and activity of catalase, glutathione peroxidase, and superoxide dismutase, and decreased pH_30min, pH_24h, cooking loss, and malondialdehyde content. OEO increased the concentrations of polyunsaturated fatty acids and conjugated linoleic acid. In contrast, saturated fatty acids decreased, accompanied by increased essential amino acids, flavor amino acids, and total amino acids in the longissimus thoracis muscle. In summary, dietary OEO supplementation promotes the nutritional and meat quality of beef by maintaining its water-holding capacity and meat color, enhancing its antioxidative capacity, and preventing lipid oxidation.

Background: Many countries have already banned the use of antibiotics in animal husbandry, making it extremely difficult to maintain animal health in livestock breeding. In the livestock industry, there is an urgent need to develop alternatives to antibiotics which will not lead to drug resistance on prolonged use. In this study, eighteen castrated bulls were randomly divided into two groups. The control group (CK) was fed the basal diet, while the antimicrobial peptide group (AP) was fed the basal diet supplemented with 8 g of antimicrobial peptides in the basal diet for the experimental period of 270 d. They were then slaughtered to measure production performance, and the ruminal contents were isolated for metagenomic and metabolome sequencing analysis. Result: The results showed that antimicrobial peptides could improve the daily weight, carcass weight, and net meat weight of the experimental animals. Additionally, the rumen papillae diameter and the micropapillary density in the AP were significantly greater than those in the CK. Furthermore, the determination of digestive enzymes and fermentation parameters showed that the contents of protease, xylanase, and β-glucoside in the AP were greater than those in the CK. However, lipase content in the CK was greater than that in the AP. Moreover, the content of acetate, propionate, butyrate, and valerate was found to be greater in AP than those in CK. The metagenomic analysis annotated 1993 differential microorganisms at the species level. The KEGG enrichment of these microorganisms revealed that the enrichment of drug resistance-related pathways was dramatically decreased in the AP, whereas the enrichment of immune-related pathways was significantly increased. There was also a significant reduction in the types of viruses in the AP. 187 probiotics with significant differences were found, 135 of which were higher in AP than in CK. It was also found that the antimicrobial mechanism of the antimicrobial peptides was quite specific. Seven low-abundance microorganisms (Acinetobacter_sp._Ac_1271, Aequorivita soesokkakensis, Bacillus lacisalsi, Haloferax larsenii, Lysinibacillus_sp._3DF0063, Parabacteroides_sp._2_1_7, Streptomyces_sp._So13.3) were found to regulate growth performance of the bull negatively. Metabolome analysis identified 45 differentially differential metabolites that significantly different between the CK and the AP groups. Seven upregulated metabolites (4-pyridoxic acid, Ala-Phe, 3-ureidopropionate, hippuric acid, terephthalic acid, L-alanine, uridine 5-monophosphate) improve the growth performance of the experimental animals. To detect the interactions between the rumen microbiome and metabolism, we associated the rumen microbiome with the metabolome and found that negative regulation between the above 7 microorganisms and 7 metabolites. Conclusions: This study shows that antimicrobial peptides can improve the growth performance of animals while resisting viruses and harmful bacteria and are expected to become healthy alternatives to antibiotics. We demonstrated a new antimicrobial peptides pharmacological model. We demonstrated low-abundance microorganisms may play a role by regulating the content of metabolites.

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.

Essential Oils (EO) are complex mixtures of plant secondary metabolites that have been proposed as promising feed additives for mitigating methane and ammonia emissions. We have previously demonstrated that Essential Oil-Cobalt (EOC) supplementation resulted in increased average daily gain and improved phenotypes (cashmere fiber traits, carcass weight, and meat quality) when cashmere goats received supplementation at approximately 2 mg/kg of body weight. However, the ruminal microbiological effects of EO remain poorly understood with regard to the extent to which ruminal populations can adapt to EO presence as feed ingredients. The effects of varying levels of EO require additional study. In this study, we conducted metagenomic analyses using ruminal fluid samples from three groups (addition of 0, 52, and 91 mg) to evaluate the influence of dietary EOC supplementation on goat rumen bacterial community dynamics. EOC addition resulted in changes of ruminal fermentation types and the EOC dose strongly impacted the stability of ruminal microbiota. The Bacteroides sp. and Succinivibrio sp. type bacterial community was positively associated with improved volatile fatty acid production when the diet was supplemented with EOC. A clear pattern was found that reflected rapid fermentative improvement in the rumen, subsequent to butyrate metabolism and EOC based feed additives may affect rumen microbes to further improve feed conversion. This observation indicates that EOC can be safely used to enhance animal productivity and to reduce ammonia and waste gas emissions, thus positively impacting the environment.

The aim of this study was to investigate the effects of dietary Allium mongolicum Regel powder (AMRP) supplementation on the growth performance, meat quality, antioxidant capacity and muscle fibre characteristics of fattening Angus calves. Growth performance data and longissimus thoracis (LT) samples were collected from four groups of fattening Angus, which were fed either a basal diet (CON) or a basal diet supplemented with an AMRP dose of 10 (LAMR), 15 (MAMR), or 20 g/animal/day AMRP (HAMR) for 120 days before slaughter. AMRP addition to the feed improved growth performance and meat quality and altered muscle fibre type. Some responses to AMRP supplementation were dose dependent, whereas others were not. Together, the results of this study demonstrated that dietary supplementation with 10 g/animal/day AMRP was the optimal dose in terms of fattening calf growth performance, while 20 g/animal/day AMRP supplementation was the optimal dose in terms of meat quality.