Limosilactobacillus johnsoni and Limosilactobacillus mucosae and Their Extracellular Vesicles Alleviate Gut Inflammatory Injury by Mediating Macrophage Polarization in a Lipopolysaccharide-Challenged Piglet Model.

BACKGROUND: Limosilactobacillus johnsoni (L. j) and Limosilactobacillus mucosae (L. m) can alleviate the inflammatory response. OBJECTIVES: This study aimed to elucidate the underlying mechanisms by which L. j- and L. m-derived extracellular vesicles (EVs) mitigate lipopolysaccharide (LPS)-induced intestinal injury. METHODS: Piglets were assigned to 4 groups: oral phosphate-buffered saline inoculation for 2 wk prior to intraperitoneal injection of physiological saline or LPS, and oral L. j/L. m inoculation for 2 wk prior to intraperitoneal injection of LPS. The intestinal integrity, macrophage markers, cytokine levels, and microbiota were determined. The cytokine levels and macrophage phenotype were detected after L. j/L. m and their EVs were coincubated with macrophages. The levels of cytokines, tight junction proteins, and apoptosis were measured after intestinal epithelial cells were cocultured with macrophages. RESULTS: LPS challenge decreased jejunal villus length; expression levels of zonula occludens-1 (ZO-1), occludin, arginase-1 (Arg1), and interleukin (IL)-10; and number of CD163+ cells and increased the expression levels of inducible nitric oxide synthase (iNOS), IL-1ß, IL-6, and tumor necrosis factor (TNF)-α compared with that in the control. L. j and L. m pretreatment rescued the aforementioned indicators compared with LPS challenge. Pretreatment of L. j and L. m and their EVs reversed the levels of IL-1ß, IL-6, TNF-α, and IL-10 and the gene expression of iNOS and Arg1 in the LPS group in macrophages. Pretreatment with L. j and L. m-derived EVs increased ZO-1 and occludin mRNA expression and reduced IL-1ß, caspase-3, and bax gene expression in intestinal epithelial cells of the coculture system. Enzyme-treated EVs were less effective than native EVs. CONCLUSIONS: This study suggests that EVs secreted by L. j and L. m control inflammation by modulating macrophage polarization, thereby improving intestinal barrier function.

Liver fat metabolism of broilers regulated by Bacillus amyloliquefaciens TL via stimulating IGF-1 secretion and regulating the IGF signaling pathway.

Bacillus amyloliquefaciens TL (B.A-TL) is well-known for its capability of promoting protein synthesis and lipid metabolism, in particular, the abdominal fat deposition in broilers. However, the underlying molecular mechanism remains unclear. In our study, the regulations of lipid metabolism of broilers by B.A-TL were explored both in vivo and in vitro. The metabolites of B.A-TL were used to simulate in vitro the effect of B.A-TL on liver metabolism based on the chicken hepatocellular carcinoma cell line (i.e., LMH cells). The effects of B.A-TL on lipid metabolism by regulating insulin/IGF signaling pathways were investigated by applying the signal pathway inhibitors in vitro. The results showed that the B.A-TL metabolites enhanced hepatic lipid synthesis and stimulated the secretion of IGF-1. The liver transcriptome analysis revealed the significantly upregulated expressions of four genes (SI, AMY2A, PCK1, and FASN) in the B.A-TL treatment group, mainly involved in carbohydrate digestion and absorption as well as biomacromolecule metabolism, with a particularly prominent effect on fatty acid synthase (FASN). Results of cellular assays showed that B.A-TL metabolites were involved in the insulin/IGF signaling pathway, regulating the expressions of lipid metabolism genes (e.g., FASN, ACCα, LPIN, and ACOX) and the FASN protein, ultimately regulating the lipid metabolism via the IGF/PI3K/FASN pathway in broilers.

Expression of Gallus Epidermal Growth Factor (gEGF) with Food-Grade Lactococcus lactis Expression System and Its Biological Effects on Broiler Chickens.

As a multifunctional polypeptide, epidermal growth factor (EGF) increases growth performance or enhances resistance to diseases in commercial broilers under adverse conditions. In this study, a recombinant Lactococcus lactis was established to produce the secretary form of bioactive gEGF. The results of in vitro testing showed that gEGF promoted the proliferation of chicken embryo fibroblast cells. A total of 63 5-day-old broiler chickens were evenly divided into three groups and treated with either M17 medium (the control group), supernatant of LL-pNZ8149 fermentation product (the P-LL group), or supernatant of LL-pNZ8149-gEGF fermentation product (the gEGF group). In two weeks, many measurements of growth, immunity and the intestines were significantly higher in the gEGF group than those in the control and the P-LL groups. Our study showed that the bioactive gEGF could be expressed with Lactococcus lactis expression system with the potential to enhance growth performance, immune function, and intestinal development in broiler chickens.

Pathogenicity and Molecular Typing of Fowl Adenovirus-Associated With Hepatitis/Hydropericardium Syndrome in Central China (2015-2018).

In central China, a large number of broiler and layer flocks have suffered from outbreaks of severe hepatitis/hydropericardium syndrome (HHS). This resulted in huge economic losses to the poultry industry, from 2015 to 2018. To identify the specific pathogen and study its pathogenicity, 195 samples from Hubei, Jiangxi, Anhui, Hunan, and Henan provinces in central China were collected. The samples were screened for the adenovirus hexon gene, and neighbor joining was used for the phylogenetic reconstruction of the sequences. Among the collected samples, 122 were found to be positive for fowl adenovirus (FAdV) by PCR, and 73 isolates were obtained. The predominant viral serotype was serotype 4 (FAdV-4), which was found in 48 isolates, while 24 were serotype 10 (FAdV-10), and one was serotype 2 (FAdV-2). The CH/HBTF /1710 isolate was selected for further experiment and inoculated into 33-day-old specific pathogen-free chickens via intramuscular injection or oral administration to evaluate pathogenicity. It was found that the mortality for chickens infected by intramuscular injection or oral administration was 70 and 60%, respectively. Necropsy revealed mild to severe hepatitis and hydropericardium at 5 and 7 days after infection. Ancestor analyses indicated that all of the FAdV-4 strains obtained in this study shared a common Indian precursor and had a close genetic relationship with the JSJ13, SDSX, HN/151025, and SDDM-15 strains common in China.