Effects of fulvic acid on growth performance, serum index, gut microbiota, and metabolites of Xianju yellow chicken

Exploring the relationship between rearing system and carcass traits of Danzhou chicken: a microbial perspective

This study investigated the effects of free-range (FR) and cage-rearing (CR) systems on intestinal health, carcass traits, and microbial diversity in the Danzhou chicken breed. Two groups of 125 hens in each group, aged 42 wk, were reared under FR and CR systems. At 50 wk, 50 hens from each group were randomly selected for carcass analysis and 10 hens for intestinal morphology and microbiota profiling. Results indicated a significant increase in villus height (VH) in the duodenum (P < 0.05), jejunum (P < 0.01), and ileum (P < 0.001) of the CR group. Additionally, the ratio of VH to crypt depth (VR) significantly (P < 0.001) increased in the jejunum, while crypt depth (CD) decreased significantly (P < 0.001) in the same section in the CR group. Carcass traits, including dress weight (DW), eviscerated with giblet weight (EGW), eviscerated weight (EW), and leg muscle weight (LW) significantly improved (P < 0.05) in the CR group. Microbial diversity showed significant β-diversity differences, with Lactobacillus, Enterococcus, and Oxalobacteraceae as dominant biomarkers in the CR group. Conversely, Actinomycetaceae, Erysipelotrichaceae, Coriobacteriaceae, Eubacterium, Actinomyces, Scardovia, and Lachnospiraceae were dominant in the FG group. Correlation analysis showed duodenum Lactobacillus was positively correlated with VH (P < 0.05), EW (P < 0.05), and LW (P < 0.001). Jejunum Lactobacillus was positively correlated considerably with VH (P < 0.01), VR (P < 0.05), DW (P < 0.05), EGW (P < 0.01), and LW (P < 0.001). Ileum Lactobacillus was positively correlated with EGW (P < 0.01), EW (P < 0.05), and LW (P < 0.01). Aeriscardovia in duodenum was positively (P < 0.01) associated with EGW. Enterococcus in the duodenum was positively (P < 0.05) associated with EGW and in Jejunum positively correlated with VH (P < 0.05) and VR (P < 0.01). The study concludes that cage rearing improves intestinal health, carcass traits, and microbial diversity in Danzhou chickens, with Lactobacillus and Enterococcus playing key roles.

Genomics and physiology of Catenibacillus, human gut bacteria capable of polyphenol C-deglycosylation and flavonoid degradation

The genus Catenibacillus (family Lachnospiraceae, phylum Bacillota) includes only one cultivated species so far, Catenibacillus scindens, isolated from human faeces and capable of deglycosylating dietary polyphenols and degrading flavonoid aglycones. Another human intestinal Catenibacillus strain not taxonomically resolved at that time was recently genome-sequenced. We analysed the genome of this novel isolate, designated Catenibacillus decagia, and showed its ability to deglycosylate C-coupled flavone and xanthone glucosides and O-coupled flavonoid glycosides. Most of the resulting aglycones were further degraded to the corresponding phenolic acids. Including the recently sequenced genome of C. scindens and ten faecal metagenome-assembled genomes assigned to the genus Catenibacillus, we performed a comparative genome analysis and searched for genes encoding potential C-glycosidases and other polyphenol-converting enzymes. According to genome data and physiological characterization, the core metabolism of Catenibacillus strains is based on a fermentative lifestyle with butyrate production and hydrogen evolution. Both C. scindens and C. decagia encode a flavonoid O-glycosidase, a flavone reductase, a flavanone/flavanonol-cleaving reductase and a phloretin hydrolase. Several gene clusters encode enzymes similar to those of the flavonoid C-deglycosylation system of Dorea strain PUE (DgpBC), while separately located genes encode putative polyphenol-glucoside oxidases (DgpA) required for C-deglycosylation. The diversity of dgpA and dgpBC gene clusters might explain the broad C-glycoside substrate spectrum of C. scindens and C. decagia. The other Catenibacillus genomes encode only a few potential flavonoid-converting enzymes. Our results indicate that several Catenibacillus species are well-equipped to deglycosylate and degrade dietary plant polyphenols and might inhabit a corresponding, specific niche in the gut.

Exploring the modulatory effects of brown seaweed meal and extracts on intestinal microbiota and morphology of broiler chickens challenged with heat stress

Brown seaweed (Ascophyllum nodosum) is known for its prebiotic roles and can improve animal intestinal health by enhancing the growth of beneficial microbes and inhibiting pathogenic ones. However, the gut health-modulatory roles of brown seaweed on chickens challenged with heat stress (HS) are rarely studied. The current study examined the effects of brown seaweed meal (SWM) and extract (SWE) on the ceca microbiota and small intestinal morphology of chickens challenged or unchallenged with HS. Three hundred and thirty-six 1-day-old Ross 308 broiler chicks were randomly assigned to either a thermoneutral (TN; 24 ± 1°C); or HS room (HS; 32-34°C, 8 h/d from d 21 to 27). All birds in each room were randomly allotted to 4 treatments - control (CON), CON + 1 mL/L seaweed extract (SWE) in drinking water, CON + 2 mL/L SWE in drinking water, and CON + 2% seaweed meal (SWM) in feed and raised for 28 d. On d 14 and 28, 12 and 24 birds per treatment group, respectively, were euthanized to collect the ceca content for gut microbiota analysis and small intestinal tissues for morphological examination. On d 14, 2% SWM increased (P = 0.047) the relative abundance of cecal Fecalibacterium and all brown seaweed treatments improved jejunal villus height (VH) and VH:CD compared to the CON diet. On d 28, HS significantly reduced (P < 0.05) ileal VH, VW, and VH:CD, and duodenal VH and VH:CD. Among the HS group, 2% SWM and 2 mL/L SWE significantly increased (P < 0.05) the relative abundance of Lactobacillus, Sellimonas, and Fournierella, compared to the CON diet. HS birds fed with 2% SWM had higher ileal VH and VH:CD compared to other treatments. In summary, SWM and SWE enhanced the abundance of beneficial microbes and improved small intestinal morphology among HS chickens. This implies that seaweed could potentially alleviate HS-induced intestinal impairment in chickens.

Effects of fulvic acid on broiler performance, blood biochemistry, and intestinal microflora

To study the effects of mineral fulvic acid (FuA) on broiler performance, slaughter performance, blood biochemistry index, antioxidant function, immune performance, and intestinal microflora, 360 Arbor Acres (AA) broiler chickens with similar body weights were randomly divided into 5 groups with 6 replicates in each group and 12 chickens in each replicate in the current study. Chickens in the control group (C) were fed with the basal diet, and chickens in the test groups (I, II, III, and IV) were fed with the diet supplemented with 0.05%, 0.1%, 0.2%, and 0.3% mineral FuA, respectively. The indicators were measured on the hatching day, d 21 and d 35. From the whole experimental period, FuA supplement significantly increased average body weight (ABW) (P < 0.05), average daily gain (ADG) of broilers (P < 0.05), and thymus weight (P < 0.05) in II and IV groups, but bascially reduced the pH value of thigh meat. FuA supplement significantly improved aspartate aminotransferase (AST) activity in the group III on d 35 (P < 0.05) and the serum levels of IgA and IgG on d 21 and d 35 (P < 0.05), but reduced glutathione peroxidase (GSH-Px) level on d 21 (P < 0.05) and malondialdehyde (MDA) level in serum on d 35 (P < 0.05). FuA supplement significantly affected the abundance of Barnesiella, Lachnospiraceae, Alistipes, Lactobacillus, and Christensenellaceae on genus level. Differences between group III and other groups were significant in the genera microflora composition on d 21 and d 35. Functional analysis showed that the cecum microbiota were mainly enriched in carbohydrate metabolism, amino acid metabolism, and energy metabolism. In conclusion, FuA may potentially have significant positive effects on the growth performance and immune function of AA chickens through the modulation of the gut microbiota, and the 0.1% FuA was the best in broiler diet based on the present study.

Chicken cecal microbiota reduces abdominal fat deposition by regulating fat metabolism

Cecal microbiota plays an essential role in chicken health. However, its contribution to fat metabolism, particularly in abdominal fat deposition, which is a severe problem in the poultry industry, is still unclear. Here, chickens at 1, 4, and 12 months of age with significantly (p < 0.05) higher and lower abdominal fat deposition were selected to elucidate fat metabolism. A significantly (p < 0.05) higher mRNA expression of fat anabolism genes (ACSL1, FADS1, CYP2C45, ACC, and FAS), a significantly (p < 0.05) lower mRNA expression of fat catabolism genes (CPT-1 and PPARα) and fat transport gene APOAI in liver/abdominal fat of high abdominal fat deposition chickens indicated that an unbalanced fat metabolism leads to excessive abdominal fat deposition. Parabacteroides, Parasutterella, Oscillibacter, and Anaerofustis were found significantly (p < 0.05) higher in high abdominal fat deposition chickens, while Sphaerochaeta was higher in low abdominal fat deposition chickens. Further, Spearman correlation analysis indicated that the relative abundance of cecal Parabacteroides, Parasutterella, Oscillibacter, and Anaerofustis was positively correlated with abdominal fat deposition, yet cecal Sphaerochaeta was negatively correlated with fat deposition. Interestingly, transferring fecal microbiota from adult chickens with low abdominal fat deposition into one-day-old chicks significantly (p < 0.05) decreased Parabacteroides and fat anabolism genes, while markedly increased Sphaerochaeta (p < 0.05) and fat catabolism genes (p < 0.05). Our findings might help to assess the potential mechanism of cecal microbiota regulating fat deposition in chicken production.