Effect Of Eugenol On Alleviating LPS-induced Intestinal Inflammation In Piglets

The intestine is an important organ for digestion and absorption of nutrients in livestock and poultry,as well as for immunity.Intestinal health is of great significance for animal production.During the breeding,weaning stress can change the morphology and function of piglets’ intestines,cause intestinal inflammation and damage to the intestinal barrier function,and cause diarrhea in piglets.Therefore,improving the intestinal barrier function of piglets is an important method to improve the production and economic benefits of pig production.Eugenol has induced widespread attention due to its advantages of bacteriostasis,anti-inflammatory,antioxidant,and enhancing animal growth performance.This study used 120 healthy weaned piglets(8.9 ± 0.2kg)and intestinal epithelial cells as experimental subjects.Quantitative PCR,Western blotting,hematoxylin/eosin staining,16 s microbial sequencing,Enzyme-Linked immunosorbnent assay,and other methods were used to study the improvement effect of eugenol on intestinal barrier function,oxidative stress,and inflammation in piglets.The main research findings are as follows:Dietary supplementation with eugenol improves the growth performance of weaned piglets while alleviating oxidative stress and inflammation induced by lipopolysaccharide(LPS).(1)Adding eugenol to the diet significantly increased the average daily gain of piglets and decreased the feed weight ratio(P< 0.01);(2)Compared with the control group,the eugenol group significantly increased the activities of antioxidant enzymes glutathione peroxidase(GSH-Px)and superoxide dismutase(SOD)in serum and increased the content of total antioxidant energy(TAOC)(P< 0.05);(3)Compared with LPS group,the eugenol+LPS group significantly decreased expression of inflammatory factors Interleukin(IL)-1β and Tumor necrosis factor-α(TNF-α)in piglet serum(P< 0.01)(4)Compared with LPS group,the eugenol+LPS group significantly decreased the expression protein of Bcl-2-associated x protein(Bax)(P< 0.01)and upregulated the relative expression protein of B-cell lymphoma-2(Bcl-2)(P< 0.05).Adding eugenol to the diet increases the relative abundance of beneficial gut bacteria and alleviates LPS induced intestinal barrier function damage in weaned piglets.(1)Adding eugenol to the diet increased the height of jejunal villi and the ratio of villous glands(P< 0.01).Eugenol pretreatment significantly alleviated the decrease in gene and protein expression of closed pore zone protein-1(ZO-1)caused by LPS(P<0.01).(2)The addition of eugenol in the diet increased the relative abundance of beneficial bacteria in the intestine,and improved the intestinal microflora to a certain extent.Compared with the control group,the LPS group increased the relative abundance of Campylobacter and decreased the relative abundance of Firmicutes(P<0.05).Adding eugenol to the diet increased the relative abundance of Firmicutes in the intestine(P< 0.05).Molecular mechanism of eugenol in alleviating LPS-induced intestinal epithelial inflammation and intestinal barrier damage in piglets.(1)The optimal action concentration of eugenol on intestinal epithelial cells and the stimulation concentration and time of LPS on intestinal epithelial cells were determined: Cells were pretreated with 100 μM eugenol for 24 hours,followed by 50 μg/m L LPS stimulated cells for 24 hours.(2)Eugenol pretreatment inhibited increased expression of inflammatory factors TNF-α and IL-1β induced by LPS in intestinal epithelial cells(P<0.01).Compared to the LPS group,the expression of the Toll-like receptor 4-Nuclear factor kappa-B(TLR4-NF-κB)signal pathway in key factors decreased in the eugenol+LPS group(P< 0.05).(3)Eugenol pretreatment alleviated the decrease in the expression of intestinal epithelial barrier factor ZO-1 induced by LPS(P< 0.01).In summary,eugenol can improve the growth performance of piglets,alleviate oxidative stress and inflammation caused by LPS stress,repair intestinal physical barriers,and improve intestinal microbial barriers;at the same time,it may inhibit the TLR4-NF-κB signal pathway to inhibit inflammation.