Amuc_1100, the most abundant outer membrane protein of Akkermansia muciniphila, alleviates high-fat diet (HFD)-induced hepatic lipid accumulation and modulates gut microbiota in fish; however, its mechanism and mediators remain unknown. Using zebrafish model, this study aims to determine the mechanism by which Amuc_1100 reduces HFD-induced hepatic lipid accumulation through modulation of gut microbiota.

In main study, 1-month-old zebrafish were fed a low-fat diet (LFD), HFD, or HFD supplemented with 0.01% Amuc_1100 (AM0.01) for 4 weeks. Body weight gain, hepatic lipid accumulation, microbial translocation, and gut microbiota composition were evaluated. In parallel, larvae at 5 d post-fertilization were fed the same diets for 7 d and analyzed by Oil Red O staining. In validation experiments, germ-free (GF) zebrafish received microbiota transplants from donor fish fed HFD or AM0.01. Antibiotics (ABS)-treated zebrafish were fed LFD, HFD, or AM0.01 for 4 weeks. Intestinal protein interacting with Amuc_1100 was identified via pull-down and co-immunoprecipitation, and its role was confirmed using protein-protein interaction (PPI) inhibitor BV02 and gene knockdown. Data were analyzed by Student's t-test or one-way ANOVA.

Compared with HFD group, zebrafish in AM0.01 group showed lower body weight gain, reduced hepatic lipid accumulation, and decreased microbial translocation (P < 0.05). AM0.01 feeding increased Bacillus abundance while reducing Acinetobacter, Plesiomonas and Aeromonas abundances relative to HFD (P < 0.05). GF zebrafish colonized with microbiota from AM0.01-fed donors showed less hepatic lipid accumulation than those receiving microbiota from HFD-fed donors (P < 0.05). In contrast, ABS-treated zebrafish showed no significant difference in hepatic triacylglycerol content between HFD and AM0.01 groups (P > 0.05). Using pull-down assays with intestinal proteins from LFD-fed zebrafish, we identified 14-3-3β/α-A as an interacting protein of Amuc_1100. When 14-3-3β/α-A PPI was inhibited by BV02, Amuc_1100 failed to alter the HFD-induced gut microbiota profile in 1-month-old zebrafish (P > 0.05). Moreover, either BV02 treatment or 14-3-3β/α-A knockdown abolished the protective effect of Amuc_1100 against hepatic lipid accumulation in conventional and GF zebrafish (P < 0.05).

Amuc_1100 reduces hepatic lipid accumulation by modulating gut microbiota through intestinal 14-3-3β/α-A, highlighting its potential as a therapeutic target.

Fibro-adipogenic progenitors (FAPs) serve as the developmental origin of intramuscular adipocytes in skeletal muscle. Enhancing their adipogenic transition could increase intramuscular fat (IMF) deposition, thereby improving meat flavor in chickens. However, critical aspects of FAPs including their cellular composition, dynamic changes during skeletal muscle growth, and associated regulatory mechanisms remain poorly understood. Therefore, we comprehensively characterized FAPs in Langshan chickens from d 1 to d 98 using both in vivo and in vitro approaches combined with single-nucleus RNA sequencing (snRNA-seq) analysis.

Our analysis of IMF contents and adipogenesis-related gene expression in the pectoralis major muscle of Langshan chickens revealed that the adipogenic properties of FAPs peaked at d 1, reached its lowest point at d 14, and subsequently increased until d 98. The snRNA-seq analysis successfully identified the population of FAPs along with their 5 subtypes including the pre-adipogenic, adipogenic, and fibrotic FAPs. The ratio of the pre-adipogenic subtype decreased from d 14 to d 98, which was reversely correlated with the changes of the adipogenic subtype, suggesting a differentiating process. Furthermore, RNA velocity and pseudo-trajectory analysis revealed that the initial FAPs had superior fibrotic capacity but decreased over time which contrasted with their enhanced adipogenic capacity with development. Notably, BMPER was identified as an important regulator for the adipogenic differentiation of FAPs, which was also confirmed by in vitro over-expression studies. In addition, the expression of BMPER in the adipogenic portion of FAPs was found to be highly conserved across human and mouse skeletal muscles.

Our study provides the first comprehensive atlas of FAPs in the skeletal muscle of chickens and identifies BMPER as a key regulator for the adipogenic differentiation of FAPs. The findings will not only provide novel targets for breeding chickens with high IMF content but also offer significant insights into understanding the cell fate decision of FAPs under both physiological and pathological conditions across species.

The overuse of antibiotics in both veterinary and human medicine has resulted in the emergence of antibiotic-resistant bacteria, prompting a search for effective alternatives. Antimicrobial peptides (AMPs) are short, often cationic, peptide-based molecules with antimicrobial and immunomodulatory activity, which makes them promising alternatives to conventional antibiotics in poultry production.

From a prior machine-learning-guided screen of 875 candidate AMPs against a wide bacterial panel, 62 exhibited activity against avian pathogenic Escherichia coli (APEC) and low in vitro hemolytic and cytotoxic activity. We selected three lead AMPs from this list (named TeRu4, TeBi1, and PeNi4), and evaluated their in vitro and in vivo efficacy, safety, and immunomodulatory potential for use in poultry farming. In animal experiments, AMPs were administered via in ovo injection on d 18 of embryonic development. In APEC challenge trials, yolk sacs were inoculated with APEC post-hatch to assess early chick mortality, while in pen trials, birds were raised in a commercial production setting for 35 d. For challenged birds, TeBi1 (10 μg/egg) significantly reduced culture-positive rates for APEC in the air sac and pericardium, increased body weight by 50% and reduced cytokine transcript levels by 10%-30% on d 7 post hatch. In HD11 chicken macrophage-like cultured cells, TeRu4 (16 μg/mL) suppressed lipopolysaccharide (LPS)-induced pro-inflammatory cytokine transcript levels. In pen trials, TeRu4 (20 μg/egg) increased the survival probability of female birds by 4.9%, while TeBi1 (20 μg/egg) increased the survival probability of all birds by 4.4%, by d 35. Gene expression analysis revealed AMP- and sex-specific cytokine responses. In pen trials, no significant differences were observed in mean weights, feed conversion ratio (FCR), and flock uniformity on d 35. By integrating high-throughput in ovo automation with large-scale commercial pen trials, this study provides a systematic translational bridge from in silico AI discovery to field-relevant poultry production interventions.

These findings demonstrate that TeBi1 and TeRu4 are promising antibiotic alternatives that improve survival, modulate immune responses, and maintain normal growth performance in broiler chickens in this experimental setting.

The regulatory effects of glucose absorption at different sites (rumen vs. small intestine) on lipid metabolism exhibit significant variation in beef nutrition. This study aimed to investigate the regulatory pathways of rumenprotected or unprotected glucose on lipid metabolism through the rumen-jejunum axis in Xinjiang Brown cattle.

Thirty Xinjiang Brown cattle (females) with similar initial weight (410 ± 22.4 kg) were randomly assigned to 3 treatment groups (n = 10 animals per group). The experimental groups were fed a basal diet with the following daily supplements per head: 150 g palmitate coating (CON group), 150 g palmitate coating plus 150 g rumen-unprotected glucose (RUG group), and 300 g rumen-protected glucose (containing 50% glucose; RPG group). The experiment lasted for 70 d. Supplementation with both rumen-unprotected glucose and rumen-protected glucose increased chest width (P = 0.001), chest girth (P = 0.013), abdominal girth (P = 0.002), backfat thickness (P = 0.041), omental fat weight (P = 0.047), as well as serum concentrations of insulin (P < 0.001), glucagon-like peptide-1 (P < 0.001), and 5-hydroxytryptamine (P < 0.001), while decreasing the content of deoxycholic acid (P < 0.001) in the jejunum. The inclusion of rumen-unprotected glucose resulted in a trend toward higher intramuscular fat (IMF) (P = 0.064) in the longissimus thoracis, along with significant increases in C14∶0 (P = 0.042), C15∶0 (P = 0.014), and marbling score (P = 0.048), as well as significant reductions in drip loss (P = 0.022) and shear force (P = 0.041). These changes were accompanied by significant increases in dry matter intake (P = 0.001), ruminal concentrations of acetate (P = 0.022) and propionate (P = 0.011). The rumen-protected glucose supplementation elevated serum glucose (P < 0.001) level, while enhancing digestibility of ether extract (P = 0.027) and neutral detergent fiber (P = 0.027). Neither rumen-unprotected glucose nor rumen-protected glucose affected the alpha diversity and beta diversity of ruminal and jejunal microbiota (P > 0.05), but the differential bacterial biomarkers were either positively or negatively correlated with chest girth, abdominal girth, marbling score, backfat thickness, and deoxycholic acid (P < 0.05).

Rumen-unprotected glucose supplementation enhances IMF deposition and meat quality attributes through microbial volatile fatty acid-driven metabolic reprogramming.