Dietary protocatechuic acid ameliorates inflammation and up-regulates intestinal tight junction proteins by modulating gut microbiota in LPS-challenged piglets

Background: Weaning is one of the major factors that cause stress and intestinal disease in piglets. Protocatechuic acid(PCA) is an active plant phenolic acid which exists in Chinese herb, Duzhong(Eucommia ulmoides Oliver), and is also considered as the main bioactive metabolite of polyphenol against oxidative stress and inflammation. This study aimed to investigate the effect of PCA on growth performance, intestinal barrier function, and gut microbiota in a weaned piglet model challenged with lipopolysaccharide(LPS).Methods: Thirty-six piglets(Pig Improvement Company line 337 × C48, 28 d of age, 8.87 kg ± 0.11 kg BW) were randomly allocated into 3 treatments and fed with a basal diet(CTL), a diet added 50 mg/kg of aureomycin(AUR), or a diet supplemented with 4000 mg/kg of PCA, respectively. The piglets were challenged with LPS(10 μg/kg BW) on d 14 and d 21 by intraperitoneal injection during the 21-d experiment. Animals(n = 6 from each group) were sacrificed after being anesthetized by sodium pentobarbital at 2 h after the last injection of LPS. The serum was collected for antioxidant indices and inflammatory cytokines analysis, the ileum was harvested for detecting mRNA and protein levels of tight junction proteins by PCR and immunohistochemical staining, and the cecum chyme was collected for intestinal flora analysis using 16 S rRNA gene sequencing.Results: Dietary supplementation of PCA or AUR significantly increased the expression of tight junction proteins including ZO-1 and claudin-1 in intestinal mucosa, and decreased the serum levels of thiobarbituric acid reactive substances(TBARS) and IL-6, as compared with CTL group. In addition, PCA also decreased the serum levels of IL-2 and TNF-α(P < 0.05). Analysis of gut microbiota indicated that PCA increased the Firmicutes/Bacteroidetes ratio(P < 0.05). Spearman's correlation analysis at the genus level revealed that PCA reduced the relative abundance of Prevotella 9, Prevotella 2, Holdemanella, and Ruminococcus torques group(P < 0.05), and increased the relative abundance of Roseburia and Desulfovibrio(P < 0.05), whereas AUR had no significant effect on these bacteria.Conclusions: These results demonstrated that both PCA and AUR had protective effect on oxidative stress, inflammation and intestinal barrier function in piglets challenged with LPS, and PCA potentially exerted the protective function by modulating intestinal flora in a way different from AUR.

The Biofunctions of Phytochemicals and Their Applications in Farm Animals： The Nrf2/Keap1 System as a Target

Reactive oxygen species （ROS） can be caused by mechanical, thermal, infectious, and chemical stimuli, and their negative effects on the health of humans and other animals are of considerable concern. The nuclear factor （erythroid-derived 2）-like 2/Kelch-like ECH-associated protein 1 （Nrf2/Keap1） system plays a major role in maintaining the balance between the production and elimination of ROS via the regulation of a series of detoxifying and antioxidant enzyme gene expressions by means of the antioxidant response element （ARE）. Dietary phytochemicals, which are generally found in vegetables, fruits, grains, and herbs, have been reported to have health benefits and to improve the growth performance and meat quality of farm animals through the regulation of Nrf2-mediated phase II enzymes in a variety of ways. However, the enormous quantity of somewhat chaotic data that is available on the effects of phytochemicals needs to be properly classified according to the functions or mechanisms of phytochemicals, in this review, we first introduce the antioxidant properties of phytochemicals and their relation to the Nrf2/Keap1 system. We then summarize the effects of phytochemicals on the growth performance, meat quality, and intestinal microbiota of farm animals via targeting the Nrf2/Keap1 system. These exhaustive data contribute to better illuminate the underlying biofunctional properties of phytochemicals in farm animals.

Isolation and structural elucidation of antifungal compounds from Curcuma amada

Objective: To isolate and identify the antifungal compounds from Curcuma amada. Methods: The antifungal activity was measured by the diameter of colonies grown on Petri dish,microscopic observation,and CLSI microdilution methods. The antifungal compounds were isolated through bioactivity guided purification by using silica gel and high-performance liquid chromatography. Structural identification of the antifungal compounds was conducted using 1 H NMR,13 C NMR,and liquid chromatography-tandem mass spectrometry. Results: The purified antifungal compounds were zederone and furanodienone. These two compounds showed dose-dependent antifungal activity against Fusarium solani sensu lato. The concentration required for 50% growth inhibition(IC50) of FSSL ranged from 115 to 129 μM and 82 to 91 μM for zederone and furanodienone,respectively. Conclusion: This study suggested that the isolated compounds from Curcuma amada could be promising natural antifungal agents to control the diseases caused by Fusarium solani sensu lato.

Inhibitory effect of blue honeysuckle extract on high-fat-diet-induced fatty liver in mice

Blue honeysuckle is rich in polyphenols, and recently receiving attention because of its potential antioxidant and anti-inflammatory properties. Nonalcoholic fatty liver disease(NAFLD) is the leading cause of chronic liver disease that develops hepatic inflammation and metabolic syndrome. The present study aims to study the effect of blue honeysuckle extract(BHE) on fat deposition and hepatic lipid peroxidation in a high-fat-diet(HFD)-induced mouse model. Mice were fed a normal diet(ND) or a HFD containing 0.5% or 1% of BHE or not for 45 d. Liver sections were stained by hematoxylin-eosin staining.Serum lipids were measured by a clinical analyzer. Insulin was examined by ELISA, and hepatic proteins were detected by Western blotting. Dietary supplementation of BHE dose-dependently suppressed HFD-induced obesity and hepatic fat deposition. Moreover, BHE improved glucose metabolism by increasing insulin sensitivity and attenuated oxidative stress potentially by up-regulating nuclear factor(erythroid-derived 2)-like 2(Nrf2)-mediated pathway.

Dietary L-theanine alleviated lipopolysaccharide-induced immunological stress in yellow-feathered broilers

L-theanine, a natural nonprotein amino acid with a high biological activity, is reported to exert anti-stress properties. An experiment with a 3 ? 2 factorial arrangement was conducted to investigate the effects of dietary L-theanine on growth performance and immune function in lipopolysaccharide(LPS)-challenged broilers. A total of 432 one-day-old male yellow-feathered broilers were randomly assigned to 3 dietary treatments(control, antibiotic and L-theanine diets) with 2 subgroups of each(6 replicate cages;12 birds/cage). Birds from each subgroup of the 3 dietary treatments were intra-abdominally injected with the same amount of LPS or saline at 24, 25, 26 d of age. Both dietary L-theanine and antibiotic improved(P < 0.05) the growth performance of birds before LPS injection(d 1 to 21). The effect of dietary L-theanine was better(P < 0.05) than that of antibiotic. Lipopolysaccharide decreased feed intake(FI) and body weight gain(BWG) from d 22 to 28(P < 0.05), BWG and feed to gain ratio(F:G) from d 29 to 56(P < 0.05), increased mortality in different growth periods(P < 0.05), elevated the levels of serum cortisol, a1-acid glycoprotein(a1-AGP), interleukin-6(IL-6) on d 24 and 25(P < 0.05), reduced immune organ indexes and contents of jejunal mucosal secretory immunoglobulin A(s Ig A) on d 28(P < 0.05). The decreased FI and BWG, as well as increased F:G and mortality in LPS-challenged birds, were alleviated by dietary L-theanine or antibiotic from d 29 to 56 and from d 1 to 56. Dietary L-theanine mitigated the elevated serum a1-AGP level on d 25, serum IL-6 concentration on d 24 and 26, and the decreased jejunal mucosal s Ig A content on d 28 of the LPS-challenged birds. The results indicated that L-theanine had potential to alleviate LPS-induced immune stress in broilers.

Magnolol additive as a replacer of antibiotic enhances the growth performance of Linwu ducks

Magnolol rich in Magnolia officinalis is a bioactive polyphenolic compound. The aim of this study was to examine the effects of magnolol additive(MA) on growth performance, expression levels of antioxidantrelated genes, and intestinal mucosal morphology of Linwu ducks aged from 49 to 70 days, comparing with that of an antibiotic additive(colistin sulfate [CS]). A total of 275,49-day-old ducks were assigned to5 groups with 5 cages of 11 ducks each and fed diets supplemented with 0,100, 200 and 300 mg of MA/kg and 300 mg of CS/kg for 3 weeks, respectively. The results showed that the average daily body weight gain(ADG) was increased significantly in MA-fed groups(200 and 300 mg/kg), compared with the basal diet(BD) group(P < 0.05). The mRNA levels of superoxide dismutase-1(SOD1), manganese superoxide dismutase-2(MnSOD2) and catalase(CAT) were also increased significantly in MA groups(P < 0.05). In addition, hematoxylin and eosin staining revealed that Linwu ducks fed the diets with MA had more intact intestinal mucosa than those fed the BD and CS diets. In addition, ileal villus height, ileal villus height/crypt depth ratio(V/C) and duodenal V/C were also improved significantly(P < 0.05). Taken together, these data demonstrated that MA is an effective feed additive to enhance the growth performance of the Linwu ducks by improving the antioxidant and intestinal mucosal status, suggesting that MA will be a potential additive to replace antibiotic(CS).