Search Results (593)

The replacement of fishmeal (FM) in aquafeeds for carnivorous fish remains challenging due to reduced palatability and adverse effects on liver health and intestinal microbiota. Marine by-products-based additives containing fish protein hydrolysates and seaweed polysaccharides have shown potential to overcome these limitations. This study evaluated the effects of graded supplementation of Haiweisu (HWS), a multi-marine by-product formulated with squid viscera hydrolysate, small-molecule components from fish protein hydrolysate, seaweed polysaccharides, and seaweed residue as a carrier, in a FM-free diet for juvenile largemouth bass. Four isonitrogenous and isolipidic diets were prepared: a FM-free control diet (CON) and three diets supplemented with 10, 20, or 30 g/kg HWS (designated S10, S20, and S30, respectively). Each diet was fed to triplicate groups of fish (29.26 ± 2.61 g) for 56 days. Results showed that HWS supplementation linearly increased final body weight, weight gain rate, and feed intake, while significantly reducing the feed conversion ratio (p < 0.05). All HWS-supplemented groups exhibited markedly lower hepatic lipid accumulation and plasma total cholesterol levels compared with the CON group, accompanied by alleviated hepatocellular steatosis and inflammatory infiltration as revealed by Oil Red O and H&E staining. Moreover, HWS significantly enhanced intestinal microbiota alpha diversity (Ace, Chao, Sobs, and Shannon indices), decreased the relative abundance of the dominant genus Mesomycoplasma, and enriched potentially beneficial genera including Methylobacterium, Delftia, and Sphingomonas (p < 0.05). In conclusion, dietary HWS supplementation effectively improved growth performance, alleviated hepatic steatosis and inflammation, and beneficially reshaped the intestinal microbiota in juvenile largemouth bass fed a FM-free diet. These findings support HWS as a promising functional additive for sustainable FM-free aquafeeds in carnivorous fish species. Full article

This study evaluated how graded dietary nucleotide supplementation (0, 0.25, 0.5, 0.75, 1.0, and 2.0 g/kg) affects growth performance, antioxidant capacity, intestinal morphology, and gut microbiota in swamp eel (Monopterus albus) (initial body weight 10.07 ± 0.92 g). Three hundred sixty fish were randomly assigned to six diets, each in triplicate, for eight weeks. Compared with the control, nucleotide addition significantly increased final body weight, weight gain rate, and specific growth rate, and decreased feed conversion ratio (p < 0.05), with optimal results at 0.75 g/kg (HS3). Survival was 100% in all groups. Supplemented fish showed lower serum and intestinal malondialdehyde levels and higher superoxide dismutase and catalase activities (p < 0.05). Serum total protein, albumin, and triglycerides increased, whereas alanine aminotransferase, aspartate aminotransferase, and γ-glutamyl transpeptidase decreased (p < 0.05), pointing to improved hepatic and lipid metabolism. Intestinal trypsin, lipase, and amylase activities also rose markedly (p < 0.05), peaking in HS3. Histological examination revealed greater mucosal thickness and villus height (p < 0.05); in HS3, these values reached approximately 0.95 mm and 0.87 mm, respectively. Metagenomic analysis showed that 0.75–1.0 g/kg nucleotides increased alpha diversity and restructured the microbial community, enriching Bacteroidetes- and Prevotella-related taxa while reducing Proteobacteria, including Acinetobacter baumannii and Escherichia coli. LEfSe identified dose-specific discriminant taxa, and refined KEGG Level 3 pathway analysis predicted enhanced butyrate and propanoate biosynthesis, starch utilization, and purine/pyrimidine interconversion at moderate doses. Genus-level abundances of Prevotella and Bacteroides correlated inversely with serum oxidative and hepatic stress markers. Quadratic regression estimated the optimal dietary nucleotide level at 764 mg/kg (0.76 g/kg), consistent with the best-performing 0.75 g/kg group. Collectively, 0.75–0.76 g/kg dietary nucleotides optimize growth and intestinal health in M. albus through coordinated improvements in antioxidant status, digestive function, mucosal architecture, and beneficial gut microbiota remodeling. Full article

Leucine, an essential branched-chain amino acid, serves not only as a substrate for protein synthesis but also as a key regulator of placental function and fetal development. This study investigated the effects of dietary supplementation with RP-Leu during late gestation on placental development and offspring performance in Hu sheep. Sixty twin-pregnant ewes at day 80 of pregnancy were randomly assigned to either a control group (fed a basal diet) or an RP-Leu group (fed a basal diet supplemented with 19 g/day RP-Leu). The feeding trial lasted for 60 d. The ewes were slaughtered at day 140 of gestation. Maternal slaughter traits and fetal organ weights were recorded. Blood and milk samples were collected for milk composition analysis and targeted metabolomic profiling. Leucine supplementation significantly increased the percentage of milk fat content, total solid content, and the birth weight of lambs (p < 0.05). Improvements in placental morphology and antioxidant capacity were observed, including a significant increase in cotyledon density and a significant enhancement of catalase (CAT) activity (p < 0.05). Gene expression analysis indicated that the NOS3, SLC38A1 and FABP4 genes in the placental cotyledons (p < 0.05), and the VEGFA, NOS3, SLC27A1 and FABP4 genes were significantly upregulated in the maternal caruncles (p < 0.05). Plasma metabolomic profiling revealed increased L-glutamic acid levels and alterations in several amino acids, with pathway enrichment indicating involvement in amino acid metabolism and membrane transport processes. Transcriptomic analysis identified 739 differentially expressed genes, which were mainly enriched in the PI3K/Akt signaling pathway, ECM–receptor interaction pathway, and cytokine–cytokine receptor interaction pathway. Collectively, these findings suggest that RP-Leu supplementation during late gestation may enhance offspring growth by modulating amino acid metabolism, promoting placental development, and improving placental nutrient transport capacity, thereby supporting fetal growth and development. Full article

Insulin resistance (IR) is a significant risk factor for various diseases, particularly during pregnancy. Dietary patterns have been reported to influence IR susceptibility. High-protein (HP) diet has gained popularity for its role in weight management. However, whether trimethylamine N-oxide (TMAO), which is produced in the liver from gut microbiota-derived metabolites of dietary protein, influences IR remains uncertain. In this study, we established a pregnant mouse model to examine the effect of an HP diet on IR, assess its impact on liver function, and investigate associated signaling pathways. The role of gut microbiota was also evaluated. We found that the HP diet induced liver injury in pregnant mice following significantly decreased body weight. The HP diet also elevated plasma TMAO levels and upregulated hepatic FMO₃ expression. Transcriptomic analysis revealed enrichment of insulin-related signaling pathways in the HP group, with notable downregulation of the Insrr gene. IR was induced through the IRS-1/PI3K/Akt signal pathway. Gut microbiota composition was disrupted in HP group, characterized by an increased Firmicutes/Bacteroidetes ratio and a higher abundance of the TMA-producing genus Coprococcus, indicating an elevated potential for TMA generation. Furthermore, several amino acid metabolism pathways closely linked to IR were also enriched in the HP group. In conclusion, our study demonstrates that HP diet induces liver injury and increases IR risk during pregnancy. Gut microbiota contributes to this process, in part through an enhanced capacity for TMA production. These findings highlight the need for greater attention to dietary patterns in pregnancy to mitigate metabolic risks. Full article

Oropharyngeal dysphagia is prevalent in hospitalized geriatric and neurological populations and constitutes a major driver of disease-related malnutrition. Conventional texture-modified diets frequently rely on diluting solid foods with liquid agents to achieve safe swallowing consistency, a process that reduces caloric and protein density per gram and creates a so-called volume paradox, whereby large meal volumes deliver inadequate nutrients. This retrospective observational study, conducted at the Fondazione Policlinico Gemelli IRCCS in Rome, compared nutritional intake in 208 hospitalized dysphagic adults receiving either a traditional homogenized standard diet (THSD; n = 58) or a density-enriched dysphagia-prepared diet (DPD; n = 150). Following propensity-score matching, total daily energy intake was significantly higher with the DPD compared to the THSD (1024 ± 307 kcal vs. 523 ± 161 kcal; p < 0.0001), as was total protein intake (37.3 ± 12.9 g vs. 26.2 ± 12.7 g; p < 0.0001). Clinically meaningful differences were observed across all meal components, including a more than twofold advantage in breakfast protein content (6.6 ± 1.7 g vs. 3.0 ± 1.5 g). Despite these improvements, total energy and protein intake remained below estimated daily requirements in both groups, highlighting the need for systematic nutritional monitoring alongside catering optimization. These findings support density-enrichment as a practical and safe strategy for improving nutritional adequacy in dysphagic inpatients, with implications for reducing reliance on oral nutritional supplements and mitigating disease-related malnutrition in clinical settings. Full article

Background: The overall objective of this pilot diet intervention study was to determine the effect of grape powder (GP) supplementation on gut microbiota composition and inflammatory markers in individuals with Crohn’s disease (CD). Methods: Adult CD participants were recruited from the Digestive Health Institute at University Hospitals Medical Center, Cleveland. All participants were supplemented with 45 g/day of freeze-dried grape powder (equivalent to ~1.5 cups of fresh grapes) daily for 21 days. The primary outcome was the change in fecal microbiome profiles. Secondary outcomes included the absolute difference (day 21-day 0) in Harvey Bradshaw Index (HBI) score, fecal myeloperoxidase (MPO), and high-sensitivity C-reactive protein (hsCRP). Results: A total of 21 CD participants were included in the final analysis. After 21 days of GP supplementation, more than half of the participants (13, 61.9%) experienced a reduction in fecal MPO, while 80% (17) experienced either a reduction or no change in HBI score. Microbiome analysis revealed modest but directional shifts, including enrichment of Akkermansiaceae, Bacteroidaceae, Tannerellaceae, Rikenellaceae, and Monoglobaceae. While overall community structure did not significantly change at the cohort level, individualized microbiome responses as well as functional pathway shifts were observed following the intervention. Conclusions: Daily supplementation with freeze-dried grape powder for 21 days was safe and well-tolerated in adults with CD and was associated with modest shifts in gut microbiome composition. This study was registered on clinicaltrials.gov (NCT05972694; 5 February 2024). Full article

Obesity and its metabolic complications represent a major global health challenge, and food-derived bioactive peptides are emerging as promising dietary interventions. In this study, two hemp seed protein-derived tetrapeptides with pancreatic lipase (PL) and cholesterol esterase (CE) inhibitory activity, APAM and RLPA, were co-administered with a high-fat diet (HFD) to male C57BL/6J mice at 25 and 100 mg/kg body weight for 10 weeks. Both peptides dose-dependently alleviated HFD-induced body weight gain, visceral fat accumulation, hepatic steatosis, dyslipidemia, hyperglycemia, and systemic inflammation. Mechanistically, both peptides inhibited intestinal PL and CE activities and enhanced fecal lipid excretion, supporting direct suppression of intestinal fat digestion. 16S rRNA gene sequencing revealed partial restoration of HFD-disrupted gut microbiota, with APAM preferentially enriching Bifidobacterium and Roseburia, while RLPA promoted Akkermansia and Lactobacillus, accompanied by differential improvements in fecal short-chain fatty acid (SCFA) profiles. Hepatic transcriptomics identified the PPAR signaling pathway as a shared regulatory hub, and multi-omics integration revealed significant correlations linking gut microbiota, SCFA production, hepatic gene expression, and metabolic phenotypes. These findings suggest a dual-pathway anti-obesity mechanism integrating intestinal lipid digestion inhibition with gut–liver axis modulation, and highlight hemp seed protein-derived peptides as potential functional food ingredients for obesity prevention. Full article

Background: Atherosclerosis is the major pathological basis of cardiovascular diseases, while current lipid-lowering therapies remain limited by suboptimal efficacy and safety. Natural flavonoids, with their multi-target pharmacological activities, are promising candidates for anti-atherosclerotic intervention. This study investigated the protective effects and mechanisms of total flavonoids from Berberis kaschgarica Rupr. (BTF) against high-fat diet (HFD)-induced atherosclerosis in ApoE^−/− mice. Methods: Bioavailable constituents of BTF were identified by UPLC-Q-TOF-MS. Network pharmacology and bioinformatics analyses were performed to predict therapeutic targets and pathways. Male ApoE^−/− mice were fed an HFD and treated with low, medium, or high doses of BTF or atorvastatin. Serum lipid profiles, oxidative stress markers, and aortic histopathology were evaluated. Hepatic proteins related to lipid metabolism were measured by Western blotting, and fecal gut microbiota were analyzed by 16S rRNA sequencing. Results: Seven flavonoid monomers, including kaempferol, apigenin, calycosin, and dihydromyricetin, were identified as absorbed constituents in serum. Bioinformatics suggested that BTF regulates targets involved in lipid metabolism, oxidative stress, and inflammation. BTF dose-dependently decreased serum TC, TG, LDL-C, MDA, and LDH, while increasing HDL-C and the activities of SOD, GSH, and CAT. BTF also reduced atherosclerotic plaque formation and preserved aortic wall structure. Mechanistically, BTF downregulated hepatic SREBP1, ACC1, FAS, APOB, and MTP expression and improved HFD-induced gut microbiota dysbiosis by enriching Akkermansia and Lactobacillus. Conclusions: BTF attenuated HFD-induced atherosclerosis by improving lipid metabolism, enhancing antioxidant capacity, and modulating gut microbiota composition, supporting its potential as a natural anti-atherosclerotic agent. Full article

This study evaluated breast meat quality of broiler chickens following dietary inclusion of full-fat Black soldier fly (Hermetia illucens) larvae (BSFL) sourced from three food-waste production sites in a nutritionally balanced diet. Broilers were fed diets containing 0%, 3%, 6%, or 9% BSFL sourced from 3 different facilities in a 3 × 4 factorial design. At 42 days of age, breast meat samples were collected for evaluation of physicochemical traits, chemical composition, amino acid, and fatty acid profiles. Inclusion of dietary BSFL had no adverse effects on key meat quality parameters, including water-holding capacity, pH, color, cooking loss, or shear force. Breast meat protein content increased significantly in broilers fed the 9% BSFL diet compared with the control, while essential amino acid composition remained unchanged across treatments. In contrast, BSFL inclusion substantially modified the fat profile of breast meat, characterized by enrichment of short- and medium-chain saturated fatty acids, increased eicosapentaenoic acid, reduced ω-6 polyunsaturated fatty acids, and an improved ω-3/ω-6 ratio. These results demonstrate that food-waste-derived full-fat BSFL can be incorporated into broiler diets at levels up to 9% without compromising breast meat quality, while enhancing its nutritional fat profile and protein content. Full article

Dietary zeaxanthin exhibits low intestinal absorption efficiency, and circulating levels are reduced in individuals with type 2 diabetes, suggesting potential metabolic relevance. However, its role during early-stage diabetes remains incompletely understood. This study examined whether dietary zeaxanthin modulates early metabolic and inflammatory responses and influences host–microbiome interactions during early T2DM progression. Four-week-old male db/db mice and wild-type C57BL/6J mice were fed an AIN-93M diet with or without 0.02% (w/w) zeaxanthin for 4 weeks. Zeaxanthin attenuated body weight gain, adiposity, hyperinsulinemia, and circulating keratinocyte-derived chemokine levels in diabetic mice. These effects were accompanied by reduced ileal membrane localization of Niemann-Pick C1-like protein 1 and decreased hepatic expression of CD36, nuclear factor kappa B p65, and phosphoenolpyruvate carboxykinase 1, without significant improvement in fasting blood glucose or hepatic triglyceride accumulation. Cecal microbiota analysis showed reduced microbial richness in diabetic mice that was not restored by zeaxanthin; however, zeaxanthin induced selective compositional shifts, including enrichment of fermentation-associated taxa (e.g., Ruminococcaceae) and normalization of Clostridium XIVb. Predicted microbial pathways related to fermentation, amino acid biosynthesis, and cofactor metabolism were also altered. Collectively, dietary zeaxanthin modulated early metabolic and inflammatory adaptation and was associated with alterations in intestinal lipid handling, inflammatory signaling, and gut microbiome composition during early T2DM progression. Full article

Background: Dietary crude protein (CP) acts as a key nutritional factor that affects the growth performance and liver metabolism of fattening Hu sheep, with metabolizable energy (ME) representing a major confounding factor in CP-related responses. To isolate the specific effects of CP on liver metabolism and minimize energy–protein interactions, we standardized dietary ME at 9.4 MJ/kg dry matter. Methods: We then established three isoenergetic CP concentrations: 11.07%, 13.07%, and 15.11%. A total of ninety 4-month-old male Hu sheep (with an initial body weight of 27.09 ± 1.83 kg) were allocated at random to three dietary treatment groups, each containing 30 animals distributed across three replicate pens, and fed pelleted total mixed rations (PTMRs) for 75 days under pen conditions in southern Xinjiang. Exploratory combined transcriptomic and metabolomic profiling of liver tissue was conducted to characterize how graded CP levels modulate growth traits and hepatic metabolic pathways, thereby identifying the appropriate dietary CP level for efficient and sustainable fattening of Hu sheep in this region. Result: Results indicated that animals fed the 15.11% CP diet showed a significantly higher average daily gain (ADG) and cumulative weight gain compared with those fed 11.07% or 13.07% CP (p < 0.05). Exploratory multi-omics enrichment analysis demonstrated significant overrepresentation (p < 0.05) of differentially expressed genes and metabolites in key biological pathways—including bile secretion, AMP-activated protein kinase (AMPK) signaling, steroid biosynthesis, peroxisome proliferator-activated receptor (PPAR) signaling, and oxidative stress-related and oxidative phosphorylation. Correlation analyses characterized two hub genes—ATP6AP1 and LOC101119853—that were significantly and negatively correlated with ADG (p < 0.05), whereas two metabolites—calcidiol and ADP—displayed significant positive relationships with ADG (p < 0.05). Pathway-level comparisons further demonstrated that both the 13.07% vs. 15.11% CP and the 11.07% vs. 15.11% CP contrasts yielded significant enrichment in AMPK signaling and steroid biosynthesis. Notably, calcidiol and ADP both declined numerically in the 13.07% vs. 15.11% CP comparison, whereas only ADP reached statistical significance in the 11.07% vs. 15.11% CP contrast. Conclusions: Collectively, under an ME level of 9.4 MJ/kg, a dietary CP concentration of 15.11% contributes to favorable growth of 4-month-old fattening Hu sheep housed in pens in southern Xinjiang. This level is associated with improved growth performance and coordinated regulation of central hepatic regulatory networks—particularly those involved in energy homeostasis and steroidogenesis—thereby supporting metabolic stability without compromising animal health or production efficiency. These findings provide a preliminary molecular basis for precision protein nutrition in Hu sheep feeding systems and offer translational insights for optimizing ruminant nutrition under arid and semi-arid environmental constraints. All correlations indicate potential associations, not causal relationships. Full article

Purpose: Obesity is a global public health issue, and natural products that promote white fat browning and enhance thermogenesis to consume energy represent promising strategy for addressing this problem. Forsythoside A (FTA) is key bioactive constituent isolated from the fruit of Forsythia suspensa. It has been reported that FTA can alleviate metabolic disorders such as hepatic lipid accumulation induced by high-fat diet (HFD). However, research on the role of FTA in alleviating obesity by promoting white fat browning remains scarce. Materials and Methods: We intervened in diet-induced obesity (DIO) mice and differentiated 3T3-L1 cells with FTA and detected thermogenic indices and the expression of thermogenesis-related genes under the guidance of network pharmacology. Mechanistically, molecular docking combined with molecular biology techniques was employed to verify the affinity of pathway-related proteins, and the AMPK inhibitor (BML-275) was used to intervene in 3T3-L1 cells to assist in demonstrating the main pathway through which FTA stimulates white fat browning. Results: FTA significantly attenuated lipid accumulation in both in vivo and in vitro models. Gene Ontology (GO) enrichment analysis revealed that FTA may promote white adipocyte browning and mitochondrial thermogenesis. Consistent with improved energy metabolism, FTA treatment increased oxygen consumption and carbon dioxide production in mice, while maintaining the respiratory exchange ratio (RER) at approximately 0.7. In vitro, FTA enhanced cellular oxygen consumption rate (OCR) and mitochondrial density. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis combined with molecular docking identified the AMPK signaling cascade as a key potential pathway mediating FTA action. Molecular biology assays further confirmed that FTA promotes AMPK phosphorylation and activates the canonical thermogenic downstream PGC-1α/UCP1 pathway. Consistently, inhibition of AMPK with BML-275 abolished the beneficial effects of FTA in 3T3-L1 adipocytes. Conclusions: This study reveals that FTA enhances white fat browning via the AMPK pathway while increasing thermogenesis in adipose tissue. Full article

Raw rapeseed cake represents a viable alternative protein source for broiler diets, and its fermentation may reduce anti-nutritional factors while improving its feeding value. This 35-day study involved 300 one-day-old ROSS 308 chicks (three groups, four replicates/group, with 25 broilers/replicate) raised on wood shavings (16 broilers/m²). Broilers received either a control diet (corn–soybean meal) or diets supplemented with 200 g/kg of RRCs (raw rapeseed cakes) or fermented rapeseed cakes (FRCs). At the end of the trial, eight broilers per group were slaughtered, and breast and thigh samples were collected. The nutritional quality of the meat was assessed by proximate composition, fatty acid profile, and health-related lipid indices. In addition, oxidative status during shelf-life storage was evaluated based on myoglobin content (Mb), metmyoglobin concentration (metMb), total antioxidant capacity (TAC), and lipid peroxidation, determined as thiobarbituric acid reactive substances (TBARS). The omega-3 fatty acid content in fresh breast and thigh samples was significantly higher in RRC and FRC groups compared to C (p = 0.014; p = 0.0001), which significantly decreased the omega-6/omega-3 ratio for both samples (p = 0.0001). The TBARS values exhibited a significant decrease (p < 0.0001) between groups for breast and thigh samples. The TAC values showed significantly higher antioxidant capacity in RRC and FRC breasts and thigh samples compared to C, considering both group differences (p < 0.0001) and shelf-life evaluation (p = 0.001). In thigh samples, the RRC group showed lower metMB values compared to the control group (p = 0.042), whereas differences in breast samples were not statistically significant (p = 0.054). Healthy lipid indexes registered significantly lower values for experimental groups, both for breast and thigh, and for linoleic/α-linolenic acid ratio (p = 0.0001), but for atherogenicity index (AI) (p = 0.0001) and thrombogenic index (TI) (p = 0.0001) only for the RRC group, while nutritive value index (NVI) significantly increased (p = 0.0001) on both groups. In conclusion, RRC and FRC may represent sustainable alternatives to soybean meal in broiler nutrition, supporting improvements in meat lipid profile and oxidative stability. Overall, the RRC group showed more significant effects on n-3 fatty acid enrichment and lipid quality indices, whereas the FRC mainly influenced proximate composition and selected color parameters. Full article

Methionine (Met) and lysine (Lys), as primary limiting amino acids, play important roles in regulating muscle quality in aquatic animals. This study investigated the effects of dietary Met and Lys supplementation on the growth performance, antioxidant function, and muscle quality of Hefang crucian carp (HCC) using physiological and transcriptomic analyses. Fish were fed three diets for 8 weeks: a basal diet (LA) and two diets supplemented with DL-methionine at 1.7% (MA) and 3.4% (HA), respectively, while L-lysine supplementation was fixed at 3.4%. The results indicated that dietary Met and Lys supplementation had no significant effect on the growth performance of HCC (p > 0.05), but significantly reduced serum triglyceride (TG) and cholesterol levels (T-CHO) (p < 0.05). Additionally, serum total protein (TP) content was significantly increased in the MA group (p < 0.05). Analysis of serum antioxidant enzyme activities indicated that appropriate Met and Lys supplementation improved antioxidant capacity and upregulated the expression of antioxidant-related genes (Nrf2, GPX1a, GSTO1, GSTP1) in the muscle. Moreover, the MA group exhibited superior muscle hardness and gumminess, while the HA group had higher springiness and chewiness (p < 0.05). Muscle fiber density was significantly increased, whereas diameter and area showed opposite trends in fish fed 1.7% Met and 3.4% Lys (p < 0.05). Furthermore, appropriate Met and Lys supplementation significantly affected muscle fiber development genes (MyoD, MyoG, and MRF4), with MyoG highest in the HA group and MyoD and MRF4 highest in the MA group (p < 0.05). Comparative transcriptomic analysis of muscle tissue showed DEGs were mainly enriched in pathways correlated with muscle quality, involving cardiac muscle contraction, actin cytoskeleton regulation, PPAR signaling pathway and ECM–receptor interaction. Taken together, our findings enhance the understanding of the molecular mechanisms underlying the effects of dietary Met and Lys on muscle quality in HCC, providing valuable insights for the development of nutritional strategies in the aquaculture industry. Full article

Modifying the feeding habits of economically valuable carnivorous fish species towards omnivorous or herbivorous diets is of significant importance in aquaculture. In previous studies, we obtained a hybrid fish (BM) by crossing herbivorous female Megalobrama amblycephala (BSB) (♀) with carnivorous male Culter mongolicus (MC) (♂). Preliminary research indicated that BM exhibits herbivorous tendencies and rapid growth. To further evaluate the feeding characteristics and application potential of BM, this study systematically analyzed and compared BM with its parental groups, focusing on the structural traits of feeding organs, digestive enzyme activity, hepatic transcriptome, and gut microbiota features. The results demonstrate that BM possesses intermediate morphological traits in its feeding organs, with measurable ratios lying between those of BSB and MC and closer to BSB. In terms of intestinal morphology, BM also exhibits hybrid characteristics, showing greater similarity to BSB. Compared to BSB, BM exhibited significantly higher trypsin and lipase activities in both the intestine and liver (p < 0.05), although these levels remained lower than those in MC (p < 0.05) and were closer to BSB. The α-amylase activity in BM was significantly lower than in BSB (p < 0.05) but higher than in MC (p < 0.05). Regarding muscle composition, BM showed a significant increase in protein content compared to both parental lines BSB and MC (p < 0.05), while its crude fat content was significantly lower than that of the paternal line MC (p < 0.05), and showed no significant difference from the maternal line BSB. Transcriptome analysis revealed that differentially expressed genes in the liver of BM were significantly enriched in pathways related to nutrient intake and metabolism, including the MAPK signaling pathway, insulin signaling pathway, glycerophospholipid metabolism, adipocytokine signaling pathway, arginine and proline metabolism, and glycolysis/gluconeogenesis, all closely associated with feeding habits in fish. The analysis of gut microbiota showed greater similarity between BM and BSB. Overall, the findings demonstrate that BM is a high-quality hybrid fish with herbivorous tendencies and elevated muscle protein content, which highlights its considerable potential for reducing feed costs and promoting sustainable aquaculture. These results provide supporting data for the future promotion and utilization of BM. Full article