Certain strains of probiotic bacteria can secret functional substances namely digestive enzymes and functional peptides to regulate physiological conditions such as digestion and anti-oxidation, which are often incorporated in industrial broiler chick production. However, few studies have detailed the action mechanisms and effects of these bacteria on regulating growth and anti-oxidation levels in broiler chickens. Ligilactobacillus salivarius is a strain of probiotic bacteria used as dietary supplement. In the present study, Ligilactobacillus salivarius was evaluated for its secreted digestive enzymes in vitro. To detailed evaluate the action mechanisms and effects of gastrointestinal tract (GIT) microbiota on alleviating anti-oxidation levels of broiler chickens through the gut-brain axis. Ligilactobacillus salivarius was cultured and supplemented in the food of broilers to evaluate the probiotic effect on growth and anti-oxidation by modulation of gut microbial composition and its functional metabolites using metagenomic and metabolomic assays. Biochemical results showed that Ligilactobacillus salivarius secreted digestive enzymes: protease, lipase, and amylase. Broiler chickens with Ligilactobacillus salivarius supplemented for 42 days, showed increased body weights, a reduced oxidative status, decreased malondialdehyde levels, and improved activities rates of total superoxide dismutase, glutathione peroxidase IIand IV improved. The microbial composition of caecum was more abundant than those broiler without probiotics supplementation, owing 400 of total number (489) of bacterial operational taxonomic units (OTU). The genera of Lactobacillus, Megamonas, Ruminoccoccaceae, Ruminococcus, Alistipes and Helicobacter shared the dominant proportion of Candidatus _Arthromitus compared with the control chickens. These functional bacteria genera assisted in the transportation and digestion of amino acids, carbohydrates, and ions, synthesis of cellular membranes, and anti-oxidation. Uncultured_organism_g_ Anaerosporobacter, Lactobacillus salivarius, uncultured_bacterium_g_ Ruminococcaceae_UCG-014, uncultured_bacterium_g_ Peptococcus were strongly and positively correlated with body growth performance and anti-oxidation. A metabonomic assay suggested that the secreted of gamma-aminobutyric acid and monobactam was metabolized according to the Kyoto Encyclopedia of Genes and Genomes analysis. In conclusion, Ligilactobacillus salivarius optimized microbial composition of the caecum and secreted functional peptides through gut-brain axis to improve the body growth and antioxidation of broiler chicken.

Selenised glucose (SeGlu) is a newly invented organic selenium compound being synthesised through the selenisation reaction of glucose with NaHSe. We hypothesised that glucose could be used as a carrier for the stable low-valent organoselenium to enhance the selenium concentrations of eggs. To probe the effects of SeGlu on production performances of laying hens, egg selenium concentration, egg quality, and antioxidant indexes, 360 Hy-Line Brown laying hens were randomly assigned to three treatment groups fed with a basal diet alone or the diet supplemented with 5 or 10 mg/kg of Se from SeGlu. The results showed that SeGlu treatment not only enhanced (P < 0.001) the Se concentration in albumen and yolks, glutathione peroxidase activity, and total antioxidant capacity of eggs but also increased (P = 0.032) the Haugh unit of eggs being stored for 2 weeks, while the production performances and egg qualities of fresh eggs were not affected. Moreover, SeGlu supplementation linearly (P < 0.001) increased the scavenging ability of superoxide radicals in eggs. Briefly, SeGlu can enhance the selenium deposition and antioxidant activity of eggs, thereby meeting the nutritional requirement for Se-deficient humans.

Probiotics are a substitute for antibiotics in the sense of intestinal health maintenance. Clostridium butyricum and Bacillus subtilis, as probiotic bacteria, have been widely used in animal production. The aim of this study was to investigate the effects of the two probiotic bacteria in geese. A total of 288 1-day old, healthy Yangzhou geese were randomly assigned into 4 groups (A, B, C and D) with 6 replicates of 12 birds each. Group A, as control, was fed a basal diet, and the treatment groups (B, C and D) were fed the basal diet supplemented with 250 mg/kg Clostridium butyricum (the viable count was 3.0 × 10⁶ CFU/g), 250 mg/kg Bacillus subtilis (the viable count was 2.0 × 10⁷ CFU/g), or a combination of the two probiotic bacteria for 70 days, respectively. The results indicated that: compared with the control group, dietary probiotics (1) promoted the growth and feed intake of the geese, (2) increased the absolute weight of duodenum, (3) increased the antioxidative capacity (total antioxidative capacity (T-AOC), total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-PX)) of intestinal mucosa, (4) improved intestinal morphology (the ratio of villus height to crypt depth), (5) but did not induce inflammation and changes of tight junction in the intestine, which was indicated by no induction of pro/inflammatory cytokines (IL-1β, IL-6, IL-10, TNFAIP3) and tight junction related genes (TJP1 and OCLN). Moreover, dietary probiotics increased the relative abundances of Firmicutes phylum and Lactobacillus genus and decreased the relative abundances of Proteobacteria phylum or Ralstonia genus in the intestinal content. In addition, the alpha diversity (observed species, Chao1, and estimate the number of OTUs in the community(ACE)) was reduced and the predicted functions of intestinal microflora, including peptidases, carbon fixation and metabolic function of starch and sugar, were enhanced by dietary probiotics. In conclusion, dietary probiotics promote the growth of geese by their positive effects on intestinal structure and function, the composition and functions of gut microflora, and intestinal antioxidative capacity.

OTU deubiquitinase 7A (OTUD7A) can suppress inflammation signaling pathways, but it is unclear whether the gene can inhibit inflammation in goose fatty liver. In order to investigate the functions of OTUD7A and identify the genes and pathways subjected to the regulation of OTUD7A in the formation of goose fatty liver, we conducted transcriptomic analysis of cells, which revealed several genes related to inflammation and immunity that were significantly differentially expressed after OTUD7A overexpression. Moreover, the expression of interferon-induced protein with tetratricopeptide repeats 5 (IFIT5), tumor necrosis factor ligand superfamily member 8 (TNFSF8), sterile alpha motif domain-containing protein 9 (SAMD9), radical S-adenosyl methionine domain-containing protein 2 (RSAD2), interferon-induced GTP-binding protein Mx1 (MX1), and interferon-induced guanylate binding protein 1-like (GBP1) was inhibited by OTUD7A overexpression but induced by OTUD7A knockdown with small interfering RNA in goose hepatocytes. Furthermore, the mRNA expression of IFIT5, TNFSF8, SAMD9, RSAD2, MX1, and GBP1 was downregulated, whereas OTUD7A expression was upregulated in goose fatty liver after 12 days of overfeeding. In contrast, the expression patterns of these genes showed nearly the opposite trend after 24 days of overfeeding. Taken together, these findings indicate that OTUD7A regulates the expression of inflammation- and immune-related genes in the development of goose fatty liver.

No overt pathological symptoms are observed in the goose liver with severe steatosis, suggesting that geese may host unique protective mechanisms. Gas chromatography time-of-flight mass spectrometry-based metabolomics analyses of liver and intestinal contents in overfed vs. normally fed geese (26 geese in each treatment) were investigated. We found that overfeeding significantly changed the metabolic profiles of liver and intestinal contents. The differential metabolites mainly belong to fatty acids, amino acids, organic acids, and amines. The differential metabolites were involved in glycolysis/gluconeogenesis, glycerolipid metabolism, the pentose phosphate pathway, fatty acid degradation, the sphingolipid signaling pathway, and the biosynthesis of unsaturated fatty acids. Moreover, we determined the biological effects of arachidonic acid (ARA) and tetrahydrocorticosterone (TD) in goose primary hepatocytes and intestinal cells. Data showed that the mRNA expression of arachidonate 5-lipoxygenase (ALOX5) in goose primary intestinal cells was significantly induced by 0.50 mM ARA treatment. Cytochrome P-450 27A1 (CYP27A1) mRNA expression was significantly inhibited in goose primary hepatocytes by 1 µM TD treatment. In conclusion, the formation of goose fatty liver is accompanied by significant changes in the metabolic profiles of liver and intestinal contents, and the changes are closely related to the metabolisms of glucose and fatty acids, oxidative stress, and inflammatory reactions.