Effects of Antimicrobial Peptide Microcin C7 on Growth Performance, Immune and Intestinal Barrier Functions, and Cecal Microbiota of Broilers

Microcin C7 is an antimicrobial peptide produced by Escherichia coli, composed of a heptapeptide with a modified adenosine monophosphate. This study was performed to evaluate the effects of Microcin C7 as a potential substrate to traditional antibiotics on growth performance, immune functions, intestinal barrier, and cecal microbiota of broilers. In the current study, 300 healthy Arbor Acres broiler chicks were randomly assigned to one of five treatments including a corn–soybean basal diet and basal diet supplemented with antibiotic or 2, 4, and 6 mg/kg Microcin C7. Results showed that Microcin C7 significantly decreased the F/G ratio of broilers; significantly increased the levels of serum cytokine IL-10, immunoglobulins IgG and IgM, and ileal sIgA secretion; significantly decreased the level of serum cytokine TNF-α. Microcin C7 significantly increased villus height and V/C ratio and significantly decreased crypt depth in small intestine of broilers. Microcin C7 significantly increased gene expression of tight junction protein Occludin and ZO-1 and significantly decreased gene expression of pro-inflammatory and chemokine TNF-α, IL-8, IFN-γ, Toll-like receptors TLR2 and TLR4, and downstream molecular MyD88 in the jejunum of broilers. Microcin C7 significantly increased the number of Lactobacillus and decreased the number of total bacteria and Escherichia coli in the cecum of broilers. Microcin C7 also significantly increased short-chain fatty acid (SCFA) and lactic acid levels in the ileum and cecum of broilers. In conclusion, diet supplemented with Microcin C7 significantly improved growth performance, strengthened immune functions, enhanced intestinal barrier, and regulated cecal microbiota of broilers. Therefore, the antimicrobial peptide Microcin C7 may have the potential to be an ideal alternative to antibiotic.

Influence of lincomycin-spectinomycin treatment on the outcome of Enterococcus cecorum infection and on the cecal microbiota in broilers

Background Enterococcus cecorum (EC) is one of the main reasons for skeletal disease in meat type chickens. Intervention strategies are still rare and focus mainly on early antibiotic treatment of the disease, although there are no data available concerning the effectivity of this procedure. The present study aimed to investigate the effectivity of early lincomycin-spectinomycin treatment during the first week of life after EC-infection. Furthermore, the impact of lincomycin-spectinomycin treatment and EC infection on the development of cecal microbiota was investigated. Methods A total of 383 day-old broiler chicks were randomly assigned to four groups (non-infected and non-treated, non-infected and treated, EC-infected and non-treated, and EC-infected and treated). The EC-infected groups were inoculated orally with an EC suspension at the day of arrival and at study day 3. The treatment groups were treated with lincomycin-spectinomycin via the drinking water for six consecutive days, starting two hours after the first inoculation. Necropsy of 20 chickens per group was performed at study days 7, 14, 21, and 42. Bacteriological examination via culture and real-time PCR was performed to detect EC in different extraintestinal organs. Cecal samples of nine chickens per group and necropsy day were analyzed to characterize the composition of the cecal microbiota. Results No clinical signs or pathologic lesions were found at necropsy, and EC was not detected in extraintestinal organs of the EC-infected and treated birds. Lincomycin-spectinomycin promoted the growth of the bacterial genus Escherichia/Shigella and reduced the amount of potentially beneficial Lactobacillus spp. in the ceca regardless of EC-infection. Unexpectedly, the highest abundances of the genus Enterococcus were found directly after ending antibiotic treatment in both treatment groups, suggesting the growth of resistant enterococcal species. EC was not detected among the most abundant members of the genus Enterococcus. Oral EC-infection at the first day of life did not influence the development of cecal microbiota in the present study. Conclusions Lincomycin-spectinomycin treatment during the first week of life can prevent the EC-associated disease in broiler type chickens and has a direct impact on the development of the cecal microbiota. The low abundance of EC in the ceca of infected chickens underlines the pathogenic nature of the disease-causing EC strains. Further research on alternative prevention and intervention strategies is needed with regard to current efforts on reducing the use of antibiotics in livestock animals.

Shugan Hewei Decoction Alleviates Cecum Mucosal Injury and Improves Depressive- and Anxiety-Like Behaviors in Chronic Stress Model Rats by Regulating Cecal Microbiota and Inhibiting NLRP3 Inflammasome

Chronic stress is a significant cause of depression, anxiety, and intestinal mucosal injury. Gut microbiota disturbances are also associated with these disorders. Shugan Hewei Decoction (SHD), which is a traditional Chinese medicine formula developed by our team, has shown superior therapeutic effects in the treatment of depression, anxiety, and functional gastrointestinal diseases caused by chronic stress. In this study, we investigated the modulatory effect of SHD on the cecal microbiota and cecum mucosal NOD-like receptor protein 3 (NLRP3) inflammasome in a chronic unpredictable stress (CUS)/social isolation rat model. After the SHD intervention, the CUS model rats showed improvements in their depressive- and anxiety-like behaviors, as well as sustained body weight growth and improved fecal characteristics. SHD improved the cecal microbiota diversity and changed the abundance of six microbial genera. A Spearman’s correlation analysis showed a strong correlation between the NLRP3 inflammasome and CUS-perturbed cecal biomarker microbiota. SHD regulated the excessive expression of NLRP3, ASC, caspase-1, interleukin-1β (IL-1β), and IL-18 in the serum and cecum mucosa induced by CUS, as well as the activation of the Toll-like receptor 4/nuclear factor-κB signaling cascades. Our results reveal the pharmacological mechanisms of SHD and provide a validated therapeutic method for the treatment of depression, anxiety, and cecum mucosal injury.

In vitro Modeling of Chicken Cecal Microbiota Ecology and Metabolism Using the PolyFermS Platform

Continuous in vitro fermentation models provide a useful tool for a fast, reproducible, and direct assessment of treatment-related changes in microbiota metabolism and composition independent of the host. In this study, we used the PolyFermS model to mimic the conditions of the chicken cecum and evaluated three nutritive media for in vitro modeling of the chicken cecal microbiota ecology and metabolism. We observed that our model inoculated with immobilized cecal microbiota and fed with a modified Viande Levure medium (mVL-3) reached a high bacterial cell density of up to approximately 10.5 log cells per mL and stable microbiota composition, akin to the host, during 82 days of continuous operation. Relevant bacterial functional groups containing primary fibrolytic (Bacteroides, Bifidobacteriaceae, Ruminococcaceae), glycolytic (Enterococcus), mucolytic (Bacteroides), proteolytic (Bacteroides), and secondary acetate-utilizing butyrate-producing and propionate-producing (Lachnospiraceae) taxa were preserved in vitro. Besides, conserved metabolic and functional Kyoto Encyclopedia of Genes and Genomes pathways were observed between in vitro microbiota and cecal inoculum microbiota as predicted by functional metagenomics analysis. Furthermore, we demonstrated that the continuous inoculation provided by the inoculum reactor generated reproducible metabolic profiles in second-stage reactors comparable to the chicken cecum, allowing for the simultaneous investigation and direct comparison of different treatments with a control. In conclusion, we showed that PolyFermS is a suitable model for mimicking chicken cecal microbiota fermentation allowing ethical and ex vivo screening of environmental factors, such as dietary additives, on chicken cecal fermentation. We report here for the first time a fermentation medium (mVL-3) that closely mimics the substrate conditions in the chicken cecum and supports the growth and metabolic activity of the cecal bacterial akin to the host. Our PolyFermS chicken cecum model is a useful tool to study microbiota functionality and structure ex vivo.

Impact of zinc oxide, benzoic acid and probiotics on the performance and cecal microbiota of piglets

Background Intestinal health remains a key factor in animal production because it is essential for digestion, absorption and bacterial fermentation. Feed additives have been used to attenuate the weaning stress such as Zinc Oxide (ZnO) and benzoic acid (C7H6O2). The objective of this study was to evaluate the impact of of benzoic acid and probiotics (BA + P) on performance, diarrhea and cecal microbiota of piglets in the nursery phase (23 to 65 days). Results One hundred and sixty weaned piglets with an initial weight of 6.335 ± 0.698 kg and 23 days of age were submitted to four treatments: supplementation with 2500 ppm of Zinc oxide (ZnO), supplementation with a commercial blend of benzoic acid and probiotics (Bacillus licheniformis, Bacillus subtilis and Enterococcus faecium NCIMB 10415; Vevogut P®) (BA + P), supplementation with Zinc oxide plus benzoic acid and probiotics (ZnO + BA + P), and controls receiving only the basal diet without any supplementation. At 65 days of age, 32 piglets (n = 8 per treatment) were slaughtered for the evaluation of the cecal microbiota. Supplementation with ZnO and BA + P were associated with better feed conversion (P < 0.05) in the early stage (23 to 49 days) and with an improvement in all performance parameters over the entire experimental period. The occurrence of diarrhea was lower (P < 0.05) in the BA + P group. The 4 most abundant phyla along with unclassified bacteria represented 93% of all sequences. Firmicutes dominated the cecal microbiota of all groups, followed by Bacteroidetes. Richness represented by the observed number of genera and by the Chao index were statistically lower in ZnO and ZnO + BA + P supplemented animals compared to controls. The beta diversity analysis that compares similarities between bacterial communities demonstrated formation of two distinct clusters containing samples with and without supplementation with ZnO, confirming a strong influence of ZnO on the intestinal microbiota. Conclusion The use of Benzoic acid with probiotics yields similar performance results with lower impact on the gut microbiota compared to ZnO, and it should be considered as a potential alternative in swine production.