Zinc protoporphyrin IX (ZnPP) is a naturally occurring metalloporphyrin that imparts a bright red color to nitrite-free dry-cured meat products such as Parma ham. This review explores the chemical structures, spectral characteristics, and mechanisms of ZnPP formation in meat products. ZnPP exhibits distinct absorption peaks in the Soret and Q bands, as well as a characteristic fluorescence emission peak at 590 nm. Its formation involves complex biochemical processes, including endogenous enzymatic, non-enzymatic, and bacterial enzymatic pathways. Various factors influence ZnPP formation, such as pH, muscle fiber type and meat composition, processing temperature and time, oxygen levels, and the presence of nitrites. ZnPP offers significant advantages for nitrite-free meat products by providing a stable red color without the associated health risks of -nitrosamines. Furthermore, it aligns with consumer demand for clean-label products and benefits from advanced technologies that improve its scalability and industrial application. However, challenges persist in standardizing ZnPP production across diverse muscle types and optimizing its formation mechanisms. Future research should focus on developing innovative technologies to enhance ZnPP formation, exploring emerging markets for natural meat colorants, and further elucidating their mechanisms of action and potential health benefits. ZnPP is a promising natural alternative to synthetic nitrites in the meat industry and has the potential to revolutionize meat product coloration.

Freezing is a valuable technique for increasing the shelf-life of meat. However, various changes occur in the physicochemical properties of frozen meat, which are affected by the frozen storage conditions, including the freezing temperature and storage duration. Conventional methods for measuring the properties of frozen-thawed meat are destructive and time-consuming. Therefore, non-destructive real-time analyses have been developed. Non-destructive analyses are divided into spectroscopy- and imaging-based technologies. A combination of non-destructive methods and supervised learning has been used to predict the properties of frozen-thawed meat, such as lipid and protein oxidation, which are affected by frozen storage conditions. This review focuses on the changes in meat properties caused by temperature and storage duration in freezing conditions, and the non-destructive measurements used to analyze the properties of frozen-thawed meat.

This study aimed to investigate the effects of various growth conditions and nutritional stress on the rate of cell development, auto and co-aggregation abilities, cell surface hydrophobicity, adherence to HT-29 cells, and changes in cellular fatty acid composition of JNU532 (JNU532). The strain JNU532 was exposed to different stressors, including temperature variations (37°C and 42°C), salt (3% NaCl), acid (pH 4), and alkali (pH 8). Following exposure to temperature stress at 42°C, the strain demonstrated the highest levels of auto- and co-aggregation, but the lowest levels of hydrophobicity and adhesion abilities. Under acidic conditions, the strain's development remained stable, but its auto and co-aggregation abilities were enhanced compared to those grown at a temperature of 37°C and pH 6.5. Moreover, JNU532 grown at pH 4 showed relatively high cell surface hydrophobicity and adhesion abilities. However, the strain exhibited the greatest adhesion capacity when subjected to alkaline stress compared to the control and other stress groups. Gas chromatography was used to isolate and quantitatively assess the levels of intracellular oleic acid and its post-synthetic derivatives, including cis-9,10-methyleneoctadecanoic acid (C19:0 cyclo ɷ8c) and C19:0 cyclo ɷ10c/19ɷ6. The JNU532 exhibited the highest amount of oleic acid during temperature stress at 42°C. Furthermore, JNU532 demonstrated the highest yield of the oleic acid cyclopropanation product C19:0 cyclo ɷ10c/19ɷ6 under acidic conditions (pH 4). Therefore, this study the application of JNU 532 as a probiotic in the food and milk industry has laid a theoretical foundation.

Black soldier fly larvae (BSFL) are polyphagous insects, and their growth, nutritional composition, and life cycle are influenced by rearing substrates. This study examined the effects of different rearing substrates on the growth performance, antioxidant activity, and physicochemical properties of BSFL. Mandarin (M) and poultry (P) by-products were mixed at varying ratios (M10P0-M5P5) and used as rearing substrates. Larval length, width, and weight increased with a higher proportion of poultry by-products in the substrate. Notably, the weight of larvae reared on M5P5 was approximately twice that of those reared on M10P0. The highest protein content was observed in M5P5. Antioxidant activities, including 2,2-diphenyl-1-picrylhydrazyl radical scavenging ability, ferric reducing antioxidant power, hydroxyl radical scavenging activity, and total phenolic content, were also highest in M5P5. The highest acid value was recorded in M5P5 for unrefined samples and in M6P4 for refined samples. Amino acid content increased with a higher proportion of poultry by-products, whereas unsaturated fatty acid content was highest in M9P1. These findings demonstrate that incorporating animal-based by-products into rearing substrates enhances BSFL growth performance. Moreover, the use of BSFL for waste valorization offers a sustainable approach to resource utilization and waste management.

This study compared the physicochemical properties of mushroom mycelium before and after rinsing, in addition to the physicochemical and textural properties of sausages with mushroom mycelium added at 0%, 25%, 50%, 75%, and 100% ratios. Physicochemical characteristics included pH, cooking yield, electronic nose, electronic tongue, and sensory characteristics, and textural properties included viscosity, emulsion capacity, and texture. Cooking yield improved and pH significantly decreased (p<0.05) with increasing mycelium content. The electronic nose results identified key compounds, such as propenal, propan-2-one, 2,3-pentanedione, and hexanal. The electronic tongue results showed a trend in which salty, sour, and umami flavor intensity increased with increasing mycelium content. Viscosity tended to decrease with increasing mycelium content. Emulsion capacity was significantly higher in the MM75 treatment group, but significantly lower in the MM100 treatment group (p<0.05). Texture profile analysis showed that as the mycelium content increased, the hardness, cohesiveness, gumminess, elasticity, and chewiness decreased.

This study compared extracts obtained using various solvents, including ethyl acetate (EtOAc), ethanol (EtOH), isopropanol (IPA) as green solvents, and n-hexane as a conventional extraction method. The investigation involved oil extraction yields, fatty acid composition, total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl scavenging activity, total protein content, and cytotoxicity effects, providing a thorough analysis of the different extraction techniques. Oil extraction yields were significantly higher with green solvents such as EtOAc (25.33±0.01%) and IPA (21.66± 0.02%) compared to n-hexane (18.6±0.02%). Analysis of fatty acid composition revealed high monounsaturated fatty acids levels in all extracts, particularly in EtOAc and EtOH extracts. The polyunsaturated fatty acids (PUFA) to saturated fatty acids (SFA) ratio varied among the extracts, with EtOH exhibiting a favourable ratio (PUFA/SFA=1.23). The highest protein yield was achieved through EtOH extraction, with a 0.75±0.01 mg/mL concentration. The TPC analysis showed that EtOH extract had significantly higher TPC (0.70±0.02 mg GAE/g oil) compared to other solvents and exhibited significant antiradical activity (IC=1.41 mg/mL) compared to conventional n-hexane extract. Cytotoxicity studies demonstrated varying toxicity levels against HepG2 and Huh7 cells, with n-hexane extract exhibiting higher toxicity than other extracts. This study suggests that EtOAc and IPA are promising alternatives for lipid extraction from mealworms. In contrast, EtOH extraction is efficient for protein extraction and maximising polyphenol content, contributing to the potential benefits of mealworm extracts.

Limited quantity of cultured meat (CM) production in the laboratory restricts the opportunity for product development and quality assessment. As myofibrillar protein (MFP) possesses similar characteristics to CM, this study used MFP as an imitation of CM to produce an imitated hybrid cultured meat patty (IHCMP) to compare physicochemical and sensory qualities with beef meat patty (BMP) and plant-based meat patty (PBMP). Additionally, dry-aged beef crust was added to improve the taste characteristics of IHCMP and PBMP. BMP and IHCMP had lower (p<0.05) pH values than PBMP in both raw (5.62 and 5.74) and cooked (5.75 and 5.88) states. BMP and PBMP had higher (p<0.05) moisture (62.17% and 62.20%). BMP and IHCMP were darker (p<0.05) than other samples both in uncooked and cooked form. IHCMP, MFP, and BMP had lower releasing water (2.07%-2.95%). Increased (p<0.05) hardness, gumminess, chewiness, and springiness were observed in BMP and IHCMP. Beef crust improved (p<0.05) umami (2.21) and richness (2.67) quality in IHCMP as determined by the electronic tongue system. IHCMP and PBMP had higher monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA) content. Adding crust increased saturated fatty acid and MUFA content, but PUFA was reduced. Hence, the present investigation revealed the probable quality characteristics of CM products through the production of IHCMP, which will help the manufacturer of CM to develop consumer-oriented product development in the future.

Cultured meat offers a sustainable and ethical solution to the environmental and food security challenges associated with conventional meat production. In cultured meat production, scaffolds play an important role as structural and biochemical supports for cell adhesion, proliferation, and differentiation. The selection of biomaterials directly influences cellular processes and consequently shape the texture, flavor, and overall quality of the cultivated meat. This review provides a comprehensive overview of biomaterials employed in cultured meat scaffolds, encompassing sources such as animals, plants, algae, and microorganisms. The strengths and limitations of each biomaterial type are critically analyzed to guide scaffold fabrication strategies. Furthermore, potential applications are explored to address the constraints of individual biomaterials. Animal-derived biomaterials improve cell adhesion and biocompatibility by imitating extracellular substrates but are limited by high cost and low mechanical strength. Although plant-derived biomaterials are cost-effective and biodegradable, their mechanical strength and biocompatibility should be enhanced through chemical modification or combination with other biomaterials. Algae-derived biomaterials provide gelling properties but lack cell-binding sites and mechanical stability. Microbial-derived biomaterials provide high mechanical strength, while the lack of nutritional value and cell-binding sites limits their application in scaffold fabrication. Each biomaterial possesses unique properties, presenting both advantages and disadvantages. By leveraging their strengths, individual biomaterials can serve as effective sources for scaffold construction. An understanding their strengths, limitations, and suitability is crucial for designing and fabricating optimal scaffolds, ultimately enabling the successful production of cultured meat.

The study aimed to determine the optimal fat and water level for goat meat emulsion-type sausage. Proximate composition, pH, emulsion stability, cooking yield, protein solubility, water holding capacity (WHC), texture profile analysis, and sensory evaluation were performed on goat meat sausages with water additions of 5%, 10%, 15%, 20%, and 25%. Cooking yield tended to decrease as the water addition level increased, while water loss showed an increase. However, myofibrillar protein solubility and WHC showed the highest values on 15% water addition treatment. Hardness, gumminess, and chewiness tended to decrease as the moisture content increased. Sensory evaluations showed that when considering appearance, tenderness, and overall acceptability, the most superior treatment was 15%. In conclusion, it is concluded that adding 15% water would be most suitable for the production of goat meat emulsion-type sausage.

This study evaluated the functional properties of lactic acid bacteria (LAB) isolated from Vietnamese feces under various heat-treatment conditions by assessing their antioxidant activity, lipoteichoic acid (LTA) content, and immunomodulatory effects. Among the six LAB strains isolated, four ( V4, V8, V10, and V11) were selected based on their acid and bile resistance, proteolytic activity, and -galactosidase activity. Heat treatment (65°C for 60 min or 95°C for 10 min) completely inactivated LAB, reducing protein and phosphate content as treatment intensity increased. Antioxidant assays [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), 2,2-diphenyl-1-picrylhydrazyl, and ferric reducing antioxidant power] revealed comparable or superior activity in heat-treated (HT) cells compared to live cells, with V10 showing the highest activity. LTA content analysis of HT V10 showed the highest LTA content (1,244 ppm) at 65°C for 60 min, surpassing that of the commercial dead cell EF-2001. Anti-inflammatory activity tests indicated no cytotoxicity at concentrations below 10 CFU/mL, and HT cells treated at 65°C for 60 min showed the highest inhibition of nitric oxide and the lowest expression levels of inflammatory cytokines [tumor necrosis factor-, interleukin (IL)-1, IL-6]. Consequently, 65°C for 60 min was established as the optimal heat-treatment condition. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis following digestive enzyme treatment revealed that HT V10 was not degraded by amylase or pepsin, but was partially degraded by oxgall. These findings suggest that HT V10 is a promising functional ingredient with antioxidant and immunoregulatory properties and is especially suitable for the Southeast Asian market.

This study aimed to examine the effect of different deoxynivalenol (DON) concentrations on growth performance, histological alterations, fungal populations, and metabolomic profiles in pigs. Twelve weaned piglets were housed in environmentally controlled pens for four weeks. After a week of dietary and environmental adaptation, they were placed in one of the four groups, namely 1) control group, basal diet; 2) T1 group, basal diet supplemented with 1 mg DON/kg feed; 3) T2 group, basal diet supplemented with 3 mg DON/kg feed; and 4) T3 group, basal diet supplemented with 10 mg DON/kg feed. The T3 group was found to have a significantly lower final body weight and average daily gain than the others (p<0.05). As DON concentration levels increased, fibrosis was observed in liver, ileum, and rectum along with the apoptosis of liver cells. However, the gut fungal composition did not show significant differences across the treatments. Collectively, our findings indicated high DON concentrations in pigs to be associated with histological changes and growth retardation.

The goat meat industry has the potential to grow because of the increasing global population and health benefits of this meat type. However, to expand the goat meat market, it is necessary to improve meat yield and quality. In this study, we investigated the effects of crossbreeding Korean native goats (KNG) with Boer goats on meat quality and nutritional value. The KNG (n=16) and crossbred goats (CG; n=16) raised under identical conditions were used. After slaughter 24 h, the muscles were collected and analyzed for meat quality indicators, fatty acids, free amino acids (FAA), minerals, and vitamins. The CG meat had lower shear force and was lighter and redder in color than the KNG meat (p<0.05). KNG meat contained higher total polyunsaturated fatty acid, FAA, vitamin E, and trace minerals (e.g., Fe and Cu) than CG meat (p<0.05). Overall, crossbreeding affected the chemical and nutritional composition, which subsequently determined the quality, properties, and nutritional value of goat meat. This study provides valuable information on the nutritional value of goat meat, thereby promoting the consumption and trading of this meat type.

This study investigates the impact of neutral detergent fiber (NDF) content in pelleted complete diets on the weight gain, carcass characteristics, and meat quality of lambs. A total of 72 lambs (12±1 weeks old) were randomly assigned to three dietary groups: Diet 1 (20.98% NDF), Diet 2 (28.23% NDF), and Diet 3 (32.82% NDF), with 8 replicates as the experimental unit. Weight gain parameters were recorded over 84 days. At the end of the trial, carcass characteristics, body components, wholesale cuts, fat depot metrics, and physical separation were evaluated. In addition, the physical, chemical, and fatty acid profiles of the meat and the qualitative meat characteristics were assessed. All data were analyzed using one-way ANOVA and regression analysis. Lambs fed Diet 2 exhibited superior overall weight gain and improved carcass characteristics, including higher slaughter weight, empty weight, hot carcass weight, cold carcass weight, and carcass compactness index. The amounts of back fat, omental fat, mesenteric fat, meat percentage, and trimmings were also higher in Diet 2 than in the other groups. In terms of meat quality, Diet 2 resulted in lower shear force and a higher myofibril fragmentation index, indicating higher tenderness, along with substantially reduced cooking loss indicating improved meat quality. In addition, lambs fed Diet 2 had higher crude protein and polyunsaturated fatty acids content, while saturated fatty acid content decreased. In conclusion, these findings suggest that an NDF level of 28.23% in lamb diets optimizes weight gain, improves carcass characteristics, and enhances meat quality.

Recently, consumers have complained about being served over-fat pork belly on social forums; therefore, providing information about the excess fat of belly slices is necessary for meat traders and consumers. Wholesale-ready bellies of commercial pigs (66 gilts and 41 barrows) including quality grade 1 (n=55), quality grade 1 (n=24), and quality grade 2 (n=28) were used to evaluate the fat level and trimmed excessive fat of retail-ready pork belly slices by the quality grade. Each belly was prepared into 18 slices corresponding to 12 thoracic vertebrae (5-16 thoracic vertebrae) and 6 lumbar vertebrae (1-6 lumbar vertebrae). The excessive fat in slices was trimmed following the government's guidelines, and expressed as a trimming loss percentage. The fat level in each slice was analyzed using a FoodScan. When gender factor was ignored, no differences in fat level were found among the quality grade categories for all slices. When gender was considered an influencing factor, the fat level in almost barrow belly slices was higher (by 5%-6%) than in gilts, especially in the quality grade 1 and quality grade 2 (p<0.05). In all quality grades, the highest excessive fat was found in slices at 12-14 thoracic vertebrae (7.28%-11.55%), and the lowest (0.59%-5.25%) was found at the lumbar vertebras. Most of the barrow belly slices had a significantly (p<0.05) higher trimming loss than gilts in all 3 quality grades. These findings suggest that an adjustment of belly wholesale prices or following the government's cutting guidelines to ensure the interests of both traders and consumers is needed.

Edible insects are gaining notable attention as an alternative human dietary protein source. However, despite its importance in food preparation, an optimal sacrifice method for insects is under research. Therefore, this study sought a suitable sacrifice method for mealworm (), a representative edible insect. Mealworms were sacrificed via freezing, sonication, blanching, and roasting and processed into powder, the predominant form in food industries. Freezing and sonication increased the free amino acid content but significantly decreased water-adhesion capacity and acceptance scores. Blanching and roasting produced mealworm powders with higher overall acceptance scores (3.33±1.06 and 3.53±1.20, respectively) than freezing and sonication (2.00±1.00 and 2.33±1.07, respectively; p<0.05). Moreover, blanching yielded higher water- (1.84± 0.01 g/g) and oil- (1.53±0.07 g/g) adhesion capacities than roasting (1.29±0.02 and 1.21± 0.14 g/g, respectively; p<0.05). Therefore, blanching was deemed a suitable sacrifice method that potentially enhances mealworm powder usability in the food industry. Additionally, to expand the application of blanching-sacrificed mealworms, we cooked them via steaming, boiling, panfrying, and deep-fat frying and verified their characteristics. Moist-heat cooking methods (steaming and boiling) conferred chewy/juicy textures and steamed-grain/mushroom odors to mealworms; conversely, dry heat-cooked (panfrying and deep-fat frying) mealworms exhibited a crispy texture, roasting odor, and savory taste. Among the four cooking methods, panfrying yielded the highest volatile compound content, with 2-methylbutanal and isobutyraldehyde being the most abundant. Our findings provide insights into optimizing sacrifice and cooking methods to improve the quality and sensory traits of mealworms and their derived products.

Fermented sausage products are increasing in popularity. These sausages undergo fermentation and maturation at low temperatures without heating or pasteurization, and during this process, spoilage fungi can contaminate the products. Many technologies developed to control contamination are not available to small-scale farms, given their high cost. Several plant-based materials, including essential oils, have been shown to exhibit anti-fungal properties. Therefore, in this study, clove, marjoram, and black pepper essential oils were analyzed for their antifungal activity against the molds generally detected in fermented sausages. Clove essential oil was confirmed to be the most effective natural substance identified for mold reduction (inhibition zone<36 mm). The temperature stability test demonstrated high essential oil stability, indicating their efficacy remains conserved during fermentation, refrigeration, and consumption. The fermented sausage treated with both spraying and dipping treatments showed an average reduction of 1.2 and 0.6 Log CFU/g for aerobic bacteria and 0.3 and 0.4 Log CFU/g for fungi, respectively. The lack of significant quality changes between the control and treatment groups indicates that the spray treatment is considered most suitable for use during production, considering economic factors, antimicrobial effects, and quality characteristics.

Although non- staphylococci (NAS), such as coagulase-negative staphylococci (CoNS), can substantially affect human and animal health, information on NAS species distribution in poultry slaughterhouses and their antimicrobial resistance (AMR) profiles is limited. In this study, we analyzed the prevalence of NAS species and AMR profiles of NAS isolates collected from poultry slaughterhouses, including chicken carcasses and facility environments. In total, 100 NAS isolates were collected from six poultry slaughterhouses in Korea. The AMR patterns of the NAS species and the major genetic elements associated with AMR phenotypes, particularly methicillin and fluoroquinolone resistance, were determined. In addition, the prevalence of classical staphylococcal enterotoxin (SE, -) and toxic shock syndrome toxin-1 () genes among NAS isolates was examined. Among the 10 NAS species, coagulase-negative (n=49, 49%) was the most dominant species, followed by (n=16, 16%). The multiple drug resistance phenotype was identified in 67% (n=67) of the NAS isolates, with the highest resistance to erythromycin (66%) and clindamycin (62%). Furthermore, fluoroquinolone resistance was confirmed in 34 (34%) NAS isolates. Fifteen NAS isolates were -positive, harboring staphylococcal cassette chromosome (SCC) I (n=2), SCC IV (n=1), or non-typeable SCC types (n=12). Carriage of SE genes was detected in none of the NAS isolates, and was detected in only two CoNS strains. Our results suggest that NAS in poultry slaughterhouses can have potential role in the maintenance and transmission of AMR.

Cell-cultured meat, as a new type of meat food, can effectively mitigate the negative effects of conventional animal husbandry on the environment, health, and animal welfare. Muscle stem cells are the main seed cells for the production of cell-cultured meat, but their weak proliferative capacity severely limits the large-scale and low-cost production of cell-cultured meat. There is growing evidence that L-ascorbic acid (AA) has the ability to increase the efficiency of muscle stem cell proliferation and differentiation . However, the role of AA in Yanbian bovine skeletal muscle satellite cells (BSCs) and its molecular mechanisms are unknown. Therefore, in the present study, the promotional effect of AA on the proliferation and differentiation of BSCs was confirmed by the Cell Counting Kit 8 (CCK-8) assay, 5-ethyl-2'-deoxyuridine (EdU) proliferation assay, real-time quantitative PCR (RT-qPCR), immunoprotein blotting (Western blotting) and immunofluorescence assay. RT-qPCR and Western blotting results showed that AA up-regulated the expression of p-Akt, p-mTOR, and p-P70S6K genes and proteins, whereas when the mTOR pathway inhibitor rapamycin was co-treated with AA in BSCs, the expression of p-Akt, p-mTOR, and p-P70S6K genes and proteins was significantly down-regulated. In summary, data suggest that AA regulates the proliferation and differentiation of BSCs by activating the AKT/mTOR/P70S6K signaling pathway. These data provide a practical approach and theoretical basis for the efficient and low-cost manufacture of cell culture meat.

Pork belly is one of the most valuable primal cuts of pork with high preferences. Although meat quality is becoming increasingly important, defining pork belly quality is challenging owing to the structure and diversity of the preferred characteristics. This study identified the factors influencing pork belly quality traits through a literature review. In total, 55 articles related to pork belly quality were selected and summarized. The quality traits of pork belly are considered to be various factors, including belly yield (weight, length, thickness, etc.), firmness, fatty acid composition, color, and sensory properties. The quality of pork belly is influenced by various factors, such as sex, genetic parameters, carcass weight, and diet. A more diverse approach is required to comprehensively understand the quality traits and impact factors of pork bellies.

The dairy industry is a significant player in the food industry, providing essential products such as milk, cheese, butter, yogurt, and milk powder to meet the global population's needs. However, the industry's activities have resulted in significant pollution, with heavy waste generation, disposal, and effluent emissions into the environment. Properly handling dairy waste residues is a major challenge, with up to 60% of the total treatment cost in the processing unit allocated to waste management. Therefore, valorizing dairy waste into useful products presents a significant advantage for the dairy industry. Numerous studies have proposed various approaches to convert dairy waste into useful products, including thermochemical, biological, and integrated conversion pathways. This review presents an overview of these approaches and identifies the best possible method for valorizing dairy waste and by-products. The research presents up-to-date information on the recovery of value-added products from dairy waste, such as biogas, biofertilizers, biopolymers, and biosurfactants, with a focus on integrating technology for environmental sustainability. Furthermore, the obstacles and prospects in dairy waste valorization have been presented. This review is a valuable resource for developing and deploying dairy waste valorization technologies, and it also presents research opportunities in this field.

Overcrowding stress in livestock farming is a significant concern for animal health and livestock products such as meats, milk, and eggs. It affects gut health by altering microbiota and regulating neuronal nitric oxide synthase (nNOS). This study aimed to investigate the effects of overcrowding stress on the gut microbiota composition and nNOS expression. We generated an nNOS-HiBiT knock-in mouse model using the HiBiT system, a highly sensitive tool for accurately quantifying gene expression. Overcrowding stress was induced by housing twenty mice per cage (MPC20) and compared with a control group of two mice per cage (MPC2). Overcrowding stress increases nNOS levels in the hypothalamus and ileum and serum corticosterone levels. Gut microbial composition differed between the control and overcrowding stress-induced groups in the ileum, cecum, and colon. Specifically, and decreased in all three regions of MPC20, whereas in the ileum and colon and in the cecum increased in MPC20. Notably, consistently decreased when nNOS and corticosterone expression were used as covariates under overcrowding stress. These regional variations reflect the differential impact of overcrowding stress on the intestinal tract, indicating complex interactions through nNOS expression within the brain-gut-microbiome axis. Importantly, the addition of probiotic feed, particularly those containing , may counteract these decreases, leading to enhanced gut health and improved quality of livestock food products. This study enhances our understanding of the correlation between overcrowding stress and the gut microbiota, providing valuable data for improving the management environment in livestock farming.