Effect of Tea Tree Oil on the Expression of Genes Involved in the Innate Immune System in Goat Rumen Epithelial Cells

Tea tree oil inhibits hydrogen sulfide-induced oxidative damage in chicken lungs through CYP450s/ROS pathway

A large amount of hydrogen sulfide (H2S) is produced in the process of chicken breeding, which can cause serious inflammation and oxidative damage to the respiratory system of chickens. Tea tree oil (TTO) has antioxidant and anti-inflammatory properties. No studies have been reported on the use of TTO in H2S-induced lung injury in chickens. Therefore, in this study, 240 one-day-old Roman pink laying hens were randomly and equally divided into 3 groups: control group (CON), H2S exposure group (AVG, containing H2S), and TTO treatment group (TTG, containing H2S and 0.02 mL/L TTO) to establish an experimental model of TTO treatment with H2S exposure for a period of 42 d. Hematoxylin and eosin (H&E) staining was used to detect lung histopathology. Gene expression profiles were analyzed using transcriptomics. The underlying mechanism of the amelioration of lung injury by TTO was further revealed by antioxidant enzyme assays and qRT-PCR. The results showed that H2S exposure induced significant gene expression of CYP450s (CYP1B1 and CYP1C1) (P < 0.05), and caused intense oxidative stress, apoptosis and inflammation compared with CON. TTO could reduce ROS production and enhance antioxidant capacity (SOD, CAT, T-AOC, and GSH-PX) by regulating the CYP450s/ROS pathway (P < 0.05). Compared with the control group, the treatment group showed significantly decreased expression of apoptotic (Caspase-8, Caspase-3, Bid and Fas) (P < 0.05) and inflammatory (IL-4, IL-16, NF-κB, TNF-α and IFN-γ) (P < 0.05) factors in the lung. This study revealed that TTO regulated CYP450s/ROS pathway to alleviate H2S-induced lung injury in chickens. These results enrich the theory of the action mechanism of TTO on H2S-exposed chicken lungs and are of great value for the treatment of H2S-exposed animals.

Rutin alleviated lipopolysaccharide-induced damage in goat rumen epithelial cells

OBJECTIVE

Rutin, also called vitamin P, is a flavonoids from plants. Previous studies have indicated that rutin can alleviate the injury of tissues and cells by inhibiting oxidative stress and ameliorating inflammation. There is no report on the protective effects of rutin on goat rumen epithelial cells (GRECs) at present. Hence, we investigated whether rutin can alleviate lipopolysaccharide (LPS)-induced damage in GRECs.

METHODS

GRECs were cultured in basal medium or basal medium containing 1 μg/mL LPS, or 1 μg/mL LPS and 20 μg/mL rutin. Six replicates were performed for each group. After 3-h culture, the GRECs were harvested to detect the relevant parameters.

RESULTS

Rutin significantly enhanced the cell activity (p<0.05) and transepithelial electrical resistance (TEER) (p<0.01) and significantly reduced the apoptosis rate (p<0.05) of LPSinduced GRECs. Rutin significantly increased superoxide dismutase, glutathione peroxidase, and catalase activity (p<0.01) and significantly decreased lactate dehydrogenase activity and reactive oxygen species and malondialdehyde (MDA) levels in LPS-induced GRECs (p<0.01). The mRNA and protein levels of interleukin 6 (IL-6), IL-1β, and C-X-C motif chemokine ligand 8 (CXCL8) and the mRNA level of tumor necrosis factor-α (TNF-α) and chemokine C-C motif ligand 5 (CCL5) were significantly increased in LPS-induced GRECs (p<0.05 or p<0.01), while rutin supplementation significantly decreased the mRNA and protein levels of IL-6, TNF-α, and CXCL8 in LPS-induced GRECs (p<0.05 or p<0.01). The mRNA level of toll-like receptor 2 (TLR2), and the mRNA and protein levels of TLR4 and nuclear factor κB (NF-κB) was significantly improved in LPS-induced GRECs (p<0.05 or p<0.01), whereas rutin supplementation could significantly reduce the mRNA and protein levels of TLR4 (p<0.05 or p<0.01). In addition, rutin had a tendency of decreasing the protein levels of CXCL6, NF-κB, and inhibitor of nuclear factor kappa-B alpha (0.05< p<0.10). Rutin could significantly decreased interferon regulatory factor 3 mRNA expression in LPS-induced GRECs (p<0.05), whereas interferon induced protein with tetratricopeptide repeats 3 (IFIT3) and toll-interacting protein (TOLLIP) mRNA expression was not significantly different between the groups. LPS reduced the tight junction protein zonula occludin 1 (ZO-1) level in GRECs whereas rutin enhanced it. Rutin significantly improved tight junction protein Claudin-1 mRNA expression in LPS-induced GRECs (p<0.01), but could not affect tight junction protein Occludin mRNA expression.

CONCLUSION

Rutin alleviated LPS-induced barrier damage in GRECs by improving oxidation resistance and anti-inflammatory activity, which may be related to TLR/NF-κB signaling pathway inhibition.

Multi-breed host rumen epithelium transcriptome and microbiome associations and their relationship with beef cattle feed efficiency

Understanding host-microbial interactions in the rumen and its influence on desirable production traits may lead to potential microbiota manipulation or genetic selection for improved cattle feed efficiency. This study investigated the host transcriptome and its correlation with the rumen archaea and bacteria differential abundance of two pure beef cattle breeds (Angus and Charolais) and one composite beef hybrid (Kinsella) divergent for residual feed intake (RFI; low-RFI vs. high-RFI). Using RNA-Sequencing of rumen tissue and 16S rRNA gene amplicon sequencing, differentially expressed genes (FDR ≤ 0.05, |log2(Fold-change) >|2) and differentially abundant (p-value < 0.05) archaea and bacteria amplicon sequence variants (ASV) were determined. Significant correlations between gene expression and ASVs (p-value < 0.05) were determine using Spearman correlation. Interesting associations with muscle contraction and the modulation of the immune system were observed for the genes correlated with bacterial ASVs. Potential functional candidate genes for feed efficiency status were identified for Angus (CCL17, CCR3, and CXCL10), Charolais (KCNK9, GGT1 and IL6), and Kinsella breed (ESR2). The results obtained here provide more insights regarding the applicability of target host and rumen microbial traits for the selection and breeding of more feed efficient beef cattle.

Sodium Propionate Relieves LPS-Induced Inflammation by Suppressing the NF-ĸB and MAPK Signaling Pathways in Rumen Epithelial Cells of Holstein Cows

Subacute ruminal acidosis (SARA) is a prevalent disease in intensive dairy farming, and the rumen environment of diseased cows acidifies, leading to the rupture of gram-negative bacteria to release lipopolysaccharide (LPS). LPS can cause rumentitis and other complications, such as liver abscess, mastitis and laminitis. Propionate, commonly used in the dairy industry as a feed additive, has anti-inflammatory effects, but its mechanism is unclear. This study aims to investigate whether sodium propionate (SP) reduces LPS-induced inflammation in rumen epithelial cells (RECs) and the underlying mechanism. RECs were stimulated with different time (0, 1, 3, 6, 9, 18 h) and different concentrations of LPS (0, 1, 5, 10 μg/mL) to establish an inflammation model. Then, RECs were treated with SP (15, 25, 35 mM) or 10 μM PDTC in advance and stimulated by LPS for the assessment. The results showed that LPS (6h and 10 μg/mL) could stimulate the phosphorylation of NF-κB p65, IκB, JNK, ERK and p38 MAPK through TLR4, and increase the release of TNF-α, IL-1β and IL-6. SP (35 mM) can reduce the expression of cytokines by effectively inhibiting the NF-κB and MAPK inflammatory pathways. This study confirmed that SP inhibited LPS-induced inflammatory responses through NF-κB and MAPK in RECs, providing potential therapeutic targets and drugs for the prevention and treatment of SARA.

Effects of Tea Tree Oil on Production Performance, Serum Parameter Indices, and Immunity in Postpartum Dairy Cows

Tea tree oil (TTO) plays an important role in regulating lipid metabolism and has anti-inflammatory properties. In postpartum dairy cows, dry matter intake (DMI) is dramatically decreased, resulting in lipid metabolism disorder and the systemic pro-inflammatory response. However, the effects of TTO on glucolipid metabolism and immunity in postpartum dairy cows remain uninvestigated. Therefore, this study aimed to evaluate the effects of TTO on production performance, serum biochemical indicators, and immunity in postpartum dairy cows. Our results demonstrate that DMI tended to increase (p = 0.07) in the total mixed ration (TMR) diets supplemented with 0.01% TTO/dry matter (DM) basis relative to that in the control group. The 4% fat-corrected milk (FCM) content in the 0.01% and 0.02% TTO groups showed an increase (p = 0.09) compared with that in the control. Remarkably, the levels of globulin (GLO) and immunoglobulin G (IgG) were elevated (p < 0.05) in the TMR diet supplemented with 0.02% TTO compared to those in the control group. The TTO caused no profound changes in cholesterol (CHO), triglyceride (TG), high-density lipoprotein (HDL), or low-density lipoprotein (LDL). Notably, 0.02% TTO increased (p < 0.05) the serum glucose concentration relative to that in the control group. In conclusion, our results demonstrate that TTO could improve glucolipid metabolism and enhance immunity in postpartum dairy cows. It may be a novel resolution strategy for body condition recovery and the improvement of milk performance.

Growth Performance, Rumen Fermentation and Inflammatory Response on Holstein Growing Cattle Treated with Low and High Non-Fibrous Carbohydrate to Neutral Detergent Fiber Ratio Pelleted Total Mixed Ration

Twenty-four healthy castrated male Holstein growing cattle, with similar body weight (301 ± 11.5 kg), were enrolled in this study and randomly allocated into two groups (12/pen). Holstein growing cattle in the LPT (low NFC/NDF pelleted TMR) group were fed basal pelleted TMR with a low NFC/NDF ratio (NFC/NDF = 1.07), while the HPT (high NFC/NDF pelleted TMR) group were fed with a high NFC/NDF ratio diet (NFC/NDF = 1.71). The results showed that: (1) Body measurements were found to be increased for the LPT group (p < 0.05); compared with the HPT group, feed intake to gain ratio and feed cost in the LPT group were decreased by 12.24% and 15.35%, respectively (p < 0.01). Compared with the HPT group, the LPT group tended to increase chest girth. (2) Digestibility of DM and NDF in the LPT group was higher (p < 0.05) than in the HPT group, being increased by 3.41% and 4.26%, respectively, and increased digestibility of ADF in the LPT group was significant (p < 0.01). (3) The daily feed consumption of NDF in the LPT group was higher than that in the HPT group and the daily rumination time and chewing time in the LPT group were longer than that in the HPT group (p < 0.05). (4) Compared with the LPT group, the parameter of pH, microbial protein and acetate: propionate (p < 0.05) in the HPT group were decreased by 8.57%, 12.46% and 23.71%, respectively. In contrast, the concentration of total volatile fatty acids, acetate and propionate were higher (p < 0.05) in the HPT group, and increased by 13.49%, 19.59% and 52.70%, respectively. (5) Compared with the LPT group, rumen fluid in the HPT group diet up-regulated the mRNA expression levels of BRECs pro-inflammatory factor IL-1β and TNF-α (p < 0.05), and meanwhile, up-regulated the mRNA expression levels of BRECs pro-inflammatory factor IL-6 (p < 0.01); compared with the LPT group, rumen fluid in the HPT group diet up-regulated the mRNA expression levels of CCL28 and CCL20 (p < 0.05) chemokines in CCL types of BRECs; in addition, compared with the LPT group, rumen fluid in the HPT group up-regulated the mRNA expression levels of CXCL2, CXCL3, CXCL9 and CXCL14 chemokines in CXCL types of BRECs (p < 0.01), and the mRNA expression levels of the CXCL5 chemokine tended to be increased (p = 0.06).

The Role of Tea Tree Oil in Alleviating Palmitic Acid-Induced Lipid Accumulation in Bovine Hepatocytes

Tea tree oil (TTO) plays an important role in lipid metabolism, alleviating the inflammatory responses. Fatty liver is associated with lipid accumulation in hepatocytes, leading to inflammation. However, there is very limited information on the effects of TTO on lipid accumulation, and inflammation in bovine hepatocytes. This study aimed to evaluate whether TTO alleviates palmitic acid (PA)-induced lipid accumulation in bovine hepatocytes. Hepatocytes isolated from mid-lactating Holstein cows were pretreated with 100 μM PA for 72 h. Cells were either pretreated with PA alone (PA group) or with PA followed by 0.00625% TTO treatment for 12 h (PT group). Expression of fatty acid oxidant genes increased (P < 0.05) while fatty acid synthesis genes decreased (P < 0.05) in the PT group compared with the PA group. PA treatment resulted in increased (P < 0.05) expression of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), but these increases were less in the PT group (P < 0.05). Compared to the PA group, expression of phosphorylated (p)-p65 and p-inhibitor κBα (p-IκBα) was suppressed (P < 0.05) by TTO treatment. TTO treatment limited (P < 0.05) the increase in intracellular reactive oxygen species (ROS) and prevented (P < 0.05) a reduction in mitochondrial membrane potential observed in response to PA treatment. Expression of endoplasmic reticulum (ER) stress genes was reduced (P < 0.05) in the PT group compared with the PA group. Our results suggest that TTO treatment attenuates the effects of PA in hepatocytes, leading to fatty acid oxidation, decreased fatty acid synthesis, suppressed inflammatory response, and reduced ER stress. Taken together, the results of this study suggest that TTO treatment may be a promising therapeutic approach to imbalanced lipid homeostasis, inflammation and ER stress in dairy cows shortly before and after calving.

Oregano Essential Oils Promote Rumen Digestive Ability by Modulating Epithelial Development and Microbiota Composition in Beef Cattle

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.