Effect of Baicalin on Bacterial Secondary Infection and Inflammation Caused by H9N2 AIV Infection in Chickens.

H9N2 subtype avian influenza virus (H9N2 AIV) is a low pathogenic virus that is widely prevalent all over the world. H9N2 AIV causes immunosuppression in the host and often leads to high rates of mortality due to secondary infection with Escherichia. Due to the drug resistance of bacteria, many antibiotics are not effective in the treatment of secondary bacterial infection. Therefore, the purpose of this study is to find effective nonantibiotic drugs for the treatment of H9N2 AIV infection-induced secondary bacterial infection and inflammation. This study proves, for the first time, that baicalin, a Chinese herbal medicine, can regulate Lactobacillus to replace Escherichia induced by H9N2 AIV, so as to resolve the intestinal flora disorder. In addition, baicalin can effectively prevent intestinal bacterial translocation of SPF chickens' post-H9N2 AIV infection, thus inhibiting secondary bacterial infection. Furthermore, baicalin can effectively treat H9N2 AIV-induced inflammation by inhibiting intestinal structural damage, inhibiting damage to ileal mucus layer construction and tight junctions, improving antioxidant capacity, affecting blood biochemical indexes, and inhibiting the production of inflammatory cytokines. Taken together, these results provide a new theoretical basis for clinical prevention and control of H9N2 AIV infection-induced secondary bacterial infection and inflammation.

Effects of antibacterial peptide combinations on growth performance, intestinal health, and immune function of broiler chickens.

To study the effects of antibacterial peptides (ABPs) on feeding broilers, this experiment compared the 2 combinations of ABP with antibiotics by separately adding the supplement to the diet of 818 broilers as follows-antibiotics, Pratt and Full-tide, and Pratt and plant essential oil-and then the effect of them on production performance, immune function, antioxidant capacity, serum biochemical indicators, and microorganisms of the experimental flocks was investigated and compared. It was found that the aforementioned indicators among the 2 groups of ABP and the antibiotic group were close to or even better than those of antibiotics, and the combination added with plant essential oils had generally better effects. These results indicated that ABPs could improve economic benefits by promoting growth, preventing disease, and reducing the rate of death. This study deepened the research on the action mechanism of ABPs and not only explored the feasibility of ABPs as a novel feed additive for broilers but also provided experimental data and theoretical basis for the application of ABPs.

Evaluation of the efficacy of chlorogenic acid in reducing small intestine injury, oxidative stress, and inflammation in chickens challenged with Clostridium perfringens type A.

The goal of the study was testing the effects of chlorogenic acid (CA) supplementation on small intestine healthiness, growth performance, oxidative stress, inflammatory response, and blood biochemical indices in specific-pathogen-free (SPF) chickens after infection with Clostridium perfringens (CP) type A. In this study, 324 1-day-old male SPF chickens were randomly distributed into 6 groups: control group; CA group; CP infection group; CA + CP group; antibiotic group; antibiotic + CP group. All 1-day-old chickens were fed with CA or antibiotic in corresponding treatment group for 13 d. On the 14 d, the chickens in corresponding infection group were challenged with CP type A for 3 d. Samples in each group were collected when the chickens were 17 and 21 d old. This study proves for the first time that CA, a Chinese herbal medicine, can effectively improve growth performance, inhibit small intestine structural damage, improve antioxidant capacity, inhibit damage to ileal mucosal layer construction and tight junctions, inhibit inflammatory cytokines, and ameliorate blood biochemical indices. Therefore, this study provides data for CA being able to effectively alleviate small intestine damage caused by CP type A infection in chickens.

Nitrate Is Crucial for the Proliferation of Gut Escherichia coli Caused by H9N2 AIV Infection and Effective Regulation by Chinese Herbal Medicine Ageratum-Liquid.

H9N2 avian influenza virus (AIV) infection in chickens is often accompanied by secondary bacterial infection, but the mechanism is unclear. The aim of the present study was to reveal that mechanism and explore non-antibiotic treatment. 16s rRNA sequencing and metabonomics were performed in the intestinal contents of chickens infected with H9N2 AIV or H9N2 AIV and fed with ageratum-liquid (AL) to reveal the metabolite that promote intestinal Escherichia coli (E. coli) proliferation caused by H9N2 AIV, as well as to determine the regulatory effect of AL. It was found that H9N2 AIV infection led E. coli to become the dominant gut microbe and promoted E. coli translocation from the intestinal tract to the visceral tissue through the damaged intestinal barrier. H9N2 AIV infection induces inflammation in the intestinal mucosa and promotes the secretion and release of nitrate from the host intestinal epithelium. In addition, nitrate promoted E. coli proliferation in the inflamed intestinal tract following H9N2 AIV infection. Furthermore, Chinese herbal medicine AL can restore intestinal homeostasis, inhibit the production of nitrate in the intestinal epithelium and effectively prevent the proliferation and translocation of E. coli in the intestines. This is the first report on the mechanism of E. coli secondary infection induced by H9N2 AIV, where herbal medicine AL was shown to have a good preventive effect on the secondary infection.

Effect of feeding Chinese herb medicine ageratum-liquid on intestinal bacterial translocations induced by H9N2 AIV in mice.

BACKGROUND: As a low pathogenic influenza virus, avian influenza virus subtype H9N2 (H9N2 AIV) often induces high morbidity in association with secondary bacterial infections in chickens or mammals. To explore this phenomenon, the relationship between intestinal microflora changes and bacterial translocations was studied post H9N2 AIV challenge and post AIV infection plus Ageratum-liquid treatment. METHODS: Illumina sequencing, histological examination and Neongreen-tagged bacteria were used in this study to research the microbiota composition, intestinal barrier, and bacterial translocation in six weeks of BALB/c mice. RESULTS: H9N2 AIV infection caused intestinal dysbacteriosis and mucosal barrier damages. Notably, the villus length was significantly reduced (p < 0.01) at 12 dpi and the crypt depth was significantly increased (p < 0.01) at 5 dpi and 12 dpi with infection, resulting in the mucosal regular villus-length/crypt-depth (V/C) was significantly reduced (p < 0.01) at 5 dpi and 12 dpi. Moreover, degeneration and dissolution of the mucosal epithelial cells, loose of the connective tissue and partial glandular atrophy were found in infection group, indicating that intestinal barrier function was weakened. Eventually, intestinal microbiota (Staphylococcus, E. coli, etc.) overrun the intestinal barrier and migrated to liver and lung tissues of the mice at 5 and 12 dpi. Furthermore, the bacteria transferred in mesentery tissue sites from intestine at 36 h through tracking the Neongreen-tagged bacteria. Then the Neongreen-tagged bacteria were isolated from liver at 48 h post intragastrical administration. Simultaneously, Ageratum-liquid could inhibit the intestinal microbiota disorder post H9N2 AIV challenge via the respiratory tract. In addition, this study also illustrated that Ageratum-liquid could effectively prevent intestinal bacterial translocation post H9N2 AIV infection in mice. CONCLUSION: In this study, we report the discovery that H9N2 AIV infection could damage the ileal mucosal barrier and induce the disturbance of the intestinal flora in BALB/c mice resulting in translocation of intestinal bacteria. In addition, this study indicated that Ageratum-liquid can effectively prevent bacterial translocation following H9N2 infection. These findings are of important theoretical and practical significance in prevention and control of H9N2 AIV infection.

Effects of dietary yeast nucleotides supplementation on intestinal barrier function, intestinal microbiota, and humoral immunity in specific pathogen-free chickens.

Yeast nucleotides are a fine functional additive in human and animals. The effects of dietary yeast nucleotides supplementation on intestinal development, expression of intestinal barrier-related genes, intestinal microbiota, and infectious bronchitis virus (IBV) antibody titer of specific pathogen-free (SPF) chickens were investigated. A total of 60 1-d-old chickens were divided into 4 groups, each of which included 3 replicates of 5 chickens. Group 1 served as a control that was fed a basal diet. Groups 2 to 4 were fed the basal diet supplemented with 0.1%, 0.3% and 0.5% yeast nucleotides, respectively. All chickens were inoculated intranasally with inactivated IBV vaccine at day 1 and day 10. At day 17, the intestinal development, expression of intestinal barrier-related genes and microbiota were evaluated. There was a significant increased ileal villus height and villus height to crypt depth ratio in group 2 (P < 0.05). Moreover, group 4 exhibited higher expression of zonula occludens-1 (ZO-1) and Occludin gene in ileum (P < 0.05), whereas groups 2 and 3 exhibited higher expression of Mucin 2 (MUC2) and trefoil factor 2 (TFF2) gene (P < 0.05), group 2 showed lower expression of IFN-α gene (P < 0.05). Dietary yeast nucleotides increased intestinal bacterial diversity (P < 0.05), and the abundance of Lactobacillus (P < 0.05). At day 10, 17, 24, 31, 38, and 45, the serum IBV antibody titers were tested. Group 2 exhibited higher IBV antibody titer at day 17 (P < 0.05), furthermore, groups 2 to 4 reached the effective levels 1 wk earlier than control group. In conclusion, dietary yeast nucleotides supplementation can help birds to mount a faster and stronger antibody response to IBV vaccine. In addition, dietary yeast nucleotides supplementation can also promote the intestinal development and barrier-related genes expression, and diversity and richness of intestinal microbiota.

Supplementation of xanthophylls increased antioxidant capacity and decreased lipid peroxidation in hens and chicks.

The present study investigated the effects of xanthophyll supplementation on production performance, antioxidant capacity (measured by glutathione peroxidase, superoxide dismutase (SOD), catalase, total antioxidant capacity (T-AOC), and reduced glutathione:oxidised glutathione ratio (GSH:GSSG)) and lipid peroxidation (measured by malondialdehyde (MDA)) in breeding hens and chicks. In Expt 1, 432 hens were fed diets supplemented with 0 (control group), 20 or 40 mg xanthophyll/kg diet. Blood samples were taken at 7, 14, 21, 28 and 35 d of the trial. Liver and jejunal mucosa were sampled at 35 d. Both xanthophyll groups improved serum SOD at 21 and 28 d, serum T-AOC at 21 d and liver T-AOC, and serum GSH:GSSG at 21, 28 and 35 d and liver GSH:GSSG. Xanthophylls also decreased serum MDA at 21 d in hens. Expt 2 was a 2 × 2 factorial design. Male chicks hatched from 0 or 40 mg in ovo xanthophyll/kg diet of hens were fed a diet containing either 0 or 40 mg xanthophyll/kg diet. Liver samples were collected at 0, 7, 14 and 21 d after hatching. Blood samples were also collected at 21 d. In ovo-deposited xanthophylls increased antioxidant capacity and decreased MDA in the liver mainly within 1 week after hatching. Maternal effects gradually vanished during 1-2 weeks after hatching. Dietary xanthophylls increased antioxidant capacity and decreased MDA in the liver and serum mainly from 2 weeks onwards. Data suggested that xanthophyll supplementation enhanced antioxidant capacity and reduced lipid peroxidation in different tissues of hens and chicks.

Supplementation of xanthophylls decreased proinflammatory and increased anti-inflammatory cytokines in hens and chicks.

The present study investigated the effects of xanthophylls (containing 40 % of lutein and 60 % of zeaxanthin) on proinflammatory cytokine (IL-1ß, IL-6, interferon (IFN)-γ and lipopolysaccharide-induced TNF-α factor (LITAF)) and anti-inflammatory cytokine (IL-4 and IL-10) expression of breeding hens and chicks. In Expt 1, a total of 432 hens were fed diets supplemented with 0 (as the control group), 20 or 40 mg/kg xanthophylls (six replicates per treatment). The liver, duodenum, jejunum and ileum were sampled at 35 d of the trial. The results showed that both levels of xanthophyll addition decreased IL-1ß mRNA in the liver and jejunum, IL-6 mRNA in the liver, IFN-γ mRNA in the jejunum and LITAF mRNA in the liver compared to the control group. Expt 2 was a 2 × 2 factorial design. Male chicks hatched from 0 or 40 mg/kg xanthophyll diet of hens were fed a diet containing either 0 or 40 mg/kg xanthophylls. The liver, duodenum, jejunum and ileum were collected at 0, 7, 14 and 21 d after hatching. The results showed that in ovo xanthophylls decreased proinflammatory cytokine expression (IL-1ß, IL-6, IFN-γ and LITAF) in the liver, duodenum, jejunum and ileum and increased anti-inflammatory cytokine expression (IL-4 and IL-10) in the liver, jejunum and ileum mainly at 0-7 d after hatching. In ovo effects gradually vanished and dietary effects began to work during 1-2 weeks after hatching. Dietary xanthophylls modulated proinflammatory cytokines (IL-1ß, IL-6 and IFN-γ) in the liver, duodenum, jejunum and ileum and anti-inflammatory cytokine (IL-10) in the liver and jejunum mainly from 2 weeks onwards. In conclusion, xanthophylls could regulate proinflammatory and anti-inflammatory cytokine expression in different tissues of hens and chicks.