IntroductionThis study aimed to explore the effects of chlorogenic acid (CGA) on the meat quality and metabolomic profiling of Shaziling pigs.MethodsIn a 51-day experiment, 48 healthy male Shaziling pigs were randomly divided into two groups: a control (Con) group (basic diets) and a CGA-treated group (basic diets + 0.10% CGA).ResultsThe results showed that compared to the Con group, CGA supplementation tended to increase the final weight and dressing percentage of Shaziling pigs. Moreover, CGA increased the intramuscular fat (IMF) content and the pH24h value and decreased the drop loss. CGA also increased the concentrations of inosine-5′-monophosphate (IMP), glutamate, C18:1n9, and MUFAs, and decreased the content of C18:2n6, n6 PUFAs, PUFAs, n6/n3 PUFA ratio in the longissimus dorsi dorsimuscle. CGA supplementation increased the content of muscular 4-hydroxy hexenal, cinobufagin, and NAD, and decreased the content of muscular lactic acid, linoleic acid and stearidonic acid. Correlation analyses showed that these increased metabolites were positively associated with the IMP content and/or negatively associated with the drop loss, and these decreased metabolites follow the opposite pattern.DiscussionIn conclusion, these results indicated that CGA could improve the meat quality of Shaziling pigs, and the effects might be associated with improved muscular metabolites.

Methionine (Met) is known to enhance antioxidant defense and reproductive efficiency in sows, but its role under low-protein feeding conditions is unclear. This study evaluated the effects of Met supplementation on lactation performance, antioxidant status, and gut microbiota of sows and their piglets. Sixty-six multiparous sows with two parity and similar body weight (244.1 ± 1.73 kg) were assigned to a normal protein diet (18% crude protein [CP]) or low-protein diets (15% CP) containing graded standardized ileal digestible (SID) Met levels (0.23%, 0.30%, 0.37%, 0.44%, and 0.51%, respectively) from d 107 of gestation to d 21 of lactation, with 11 replicates in each group and 1 sow per replicate. The results showed that low-protein diets supplemented with 0.30% Met achieved milk yield and piglet growth comparable to the normal protein group (P > 0.05). In addition, 0.30% Met supplementation reduced serum urea nitrogen content, enhanced the concentrations of milk immunoglobulin M, glutathione, and taurine, and increased the activities of serum total superoxide dismutase in sows and glutathione peroxidase in piglets when compared with the normal protein diet (P < 0.05). Microbiome analysis indicated higher relative abundance of Christensenellaceae_R-7_group in piglets from the 0.30% Met group, positively correlated with growth traits. These findings suggest that a 0.30% Met level in a 15% CP diet supports sow performance and piglet development comparable to normal protein feeding through improved antioxidant capacity and beneficial microbial modulation.

The potential changes in limiting amino acid (AA) requirements for lactating sows fed low-protein (LP) diets and the underlying physiological mechanisms remain unclear. This study evaluated the productive and physiological responses of lactating sows to LP diets, focusing on the optimal standardized ileal digestible lysine (SID Lys) supply. A total of 84 Landrace × Large White sows with similar parity (4.06 ± 0.16), expected farrowing dates and body weight (BW; 260.65 ± 1.25 kg) were randomly assigned to 6 groups with 14 replicates in each group and 1 sow per replicate. The control diet (CON) contained 18% crude protein (CP) and 0.78% SID Lys. Five LP diets contained 15% CP and similar net energy (NE) levels, with SID Lys levels of 0.66%, 0.72%, 0.78%, 0.84%, and 0.90%, respectively, achieved by adjusting the corn-to-soybean meal ratio and crystalline amino acids (CAAs) supplementation. The trial lasted for 28 d (from d 107 of gestation to d 21 postpartum). Compared with CON, 0.78% SID Lys-LP diet increased milk immunoglobulin M content (t-test, P = 0.002), improved apparent CP digestibility, and reduced serum urea nitrogen (SUN) content at d 14 and 21 of lactation, and also reduced milk urea nitrogen concentrations (t-test, P < 0.05). However, dietary CP reduction significantly decreased serum insulin-like growth factor-1 (IGF-1) levels and the digestibility of dietary crude fiber (t-test, P < 0.05). When the dietary SID Lys level in LP diets was further decreased to 0.66%, both sow and piglet production performance significantly declined (P < 0.05). However, increasing SID Lys to 0.84% in LP diets improved piglet performance, and the overall performance of both sows and piglets was not significantly different from that of CON, with the 0.84% SID Lys-LP group demonstrating better apparent utilization of dietary nitrogen and AA compared to all other groups (P > 0.05). A nonlinear fitting of sensitive indicators with linear and quadratic effects was conducted to estimate optimal SID Lys requirements for lactating sow. Breakpoints for 14 d SUN, maximizing piglet benefits (weaning litter weight and individual weight), and sow BW loss were 0.80%, 0.81%, and 0.85% using the broken-line linear model, and 0.86%, 0.90%, and 0.90% using the broken-line quadratic model. In conclusion, the LP diet containing 0.78% SID Lys did not adversely affect sow performance but affected piglet growth performance. Reducing dietary SID Lys in LP diets impaired the growth and development of 21 d suckling piglets, whereas increasing SID Lys and supplementing CAAs (Met, Thr, Trp, and Val) restored performance and mitigates adverse effects. The broken-line linear and quadratic models suggest the optimal range of SID Lys in LP diets for sows is between 0.80% and 0.90%.

This study aimd to investigate the effects of tryptophan (Trp) supplementation in low-protein diets on sow performance and piglet growth, and its potential mechanisms. Sixty-six multiparous sows (Large White × Landrace) with similar parity (2.87 ± 0.34 parities), body weight (250.75 ± 11.24 kg), and backfat thickness (16.06 ± 1.94 mm) were randomly assigned to six groups. There were eleven sows in each group and one replicate per sow. They were fed the following diets: normal protein diets (18% crude protein [CP], control group [CON]) or low-protein diets (15% CP) containing different levels of Trp (0.15%, 0.21%, 0.27%, 0.33%, and 0.39%, respectively). The results showed that low-protein diets containing 0.21% Trp achieved performance comparable to the CON group. Specifically, no significant differences were observed between the 0.21% Trp group and the CON group in sow average daily feed intake, milk yield from 3 to 21 d, and piglet growth parameters (litter weight and individual weight at 3, 14, and 21 d, as well as average daily gain (ADG) from 3 to 21 d (P > 0.05). Furthermore, compared with the CON group, the 0.21% Trp group significantly increased the levels of fat-free dry matter and immunoglobulin A (IgA) in colostrum, reduced milk urea nitrogen (MUN), elevated serum total glutathione (T-GSH) in sows, and increased serum immunoglobulin G (IgG) in piglets (P < 0.05). Additionally, compared with the CON group, the 0.21% Trp group promoted intestinal health in piglets, as evidenced by increased ileal villus height, upregulation of intestinal physical barrier-related genes (occludin and claudin-1) in the jejunum and ileum, downregulation of pro-inflammatory cytokines (IL-6 and IFN-γ), upregulation of antioxidant genes (GSH-PX and CAT), as well as an increase in the abundance of the beneficial gut microbiota Christensenellaceae_R-7_group (P < 0.05).The experiment lasted from 107 d of gestation to 21 d of lactation. Data of this study suggested that low-protein diets containing 0.21% Trp improved sow performance and piglet growth to levels comparable to normal protein diets, probably due to the higher feed intake and milk yield of sows, the improvements in intestinal function and gut microbiota of piglets, and the higher antioxidant capacity of sows and piglets.

Abstract The substantially increased prevalence of diarrhea in infants and livestock induced by enterotoxigenic Escherichia coli (ETEC) infection threatens the intestinal health of humans and livestock. This study investigated an engineered Bacillus subtilis WB800_KR32 strain expressing antimicrobial peptide KR32 (yielding 2.24 μg/mL with peak activity at 33 h fermentation) for its preventive efficacy against ETEC K88‐induced diarrhea in a piglet model. Oral administration of WB800_KR32 could significantly improve intestinal morphology and barrier function, particularly in the ileum, reduce Escherichia relative abundance, and enhance repair and metabolism‐related pathways while increasing serum antioxidants such as glutathione. Mechanistically, WB800_KR32 significantly decreased novel‐ssc‐miR‐1250‐5p expression and its predicted target, nuclear factor kappa‐B (NFκB) p65 (p < 0.05). In vitro, 40% fermented WB800_KR32 supernatant reduced novel‐ssc‐miR‐1250‐5p expression, improved tight junction function, decreased inflammatory response, and reduced NFκB p65 phosphorylation in ETEC K88‐infected IPEC‐J2 cells (p < 0.05). These findings suggested that engineered Bacillus subtilis WB800_KR32 provides a dual‐action therapeutic platform combining targeted antimicrobial delivery with host immunomodulation, offering a promising translational strategy for preventing ETEC K88‐induced diarrhea in humans and livestock.

To compare the differences in meat quality between obese-type Chinese pig breeds and lean-type foreign pig breeds, we selected Taoyuan Black (TB) pigs and Duroc pigs at 180 and 210 days of age and analyzed their meat quality, chemical composition, and flavor compounds using an electronic tongue, chromatographic techniques, and two-dimensional gas chromatography-time-of-flight-mass-spectrometry (GC×GC-TOF-MS). A total of 16 main fatty acids, 18 main free amino acids, and 249 flavor compounds were identified. The results showed that TB pigs exhibited redder meat color, higher intramuscular fat, and lower shear force than Duroc pigs (p < 0.05). TB pigs displayed higher levels of flavor nucleotides, free amino acids, and monounsaturated fatty acids (p < 0.05). Furthermore, pigs at 180 days exhibited lower dripping loss and more flavor compounds than those at 210 days (p < 0.05). Electronic tongue analysis revealed higher umami values in TB pigs at 180 days of age. Among the flavor compounds in pork, the four compounds that contributed most significantly to flavor across all species were 2-nonenal, 2-octenal, heptanal, 2,3-butanedione, and 2-pentylfuran. These findings provide fundamental data and insight into pig production.

Adipose tissue is a critical energy reservoir in animals and humans, with multifaceted roles in endocrine regulation, immune response, and providing mechanical protection. Based on anatomical location and functional characteristics, adipose tissue can be categorized into distinct types, including white adipose tissue (WAT), brown adipose tissue (BAT), beige adipose tissue, and pink adipose tissue. Traditionally, adipose tissue research has centered on its morphological and functional properties as a whole. However, with the advent of single-cell transcriptomics, a new level of complexity in adipose tissue has been unveiled, showing that even under identical conditions, cells of the same type may exhibit significant variation in morphology, structure, function, and gene expression——phenomena collectively referred to as cellular heterogeneity. Single-cell transcriptomics, including techniques like single-cell RNA sequencing (scRNA-seq) and single-nucleus RNA sequencing (snRNA-seq), enables in-depth analysis of the diversity and heterogeneity of adipocytes at the single-cell level. This high-resolution approach has not only deepened our understanding of adipocyte functionality but also facilitated the discovery of previously unidentified cell types and gene expression patterns that may play key roles in adipose tissue function. This review delves into the latest advances in the application of single-cell transcriptomics in elucidating the heterogeneity and diversity within adipose tissue, highlighting how these findings have redefined the understanding of cell subpopulations within different adipose depots. Moreover, the review explores how single-cell transcriptomic technologies have enabled the study of cellular communication pathways and differentiation trajectories among adipose cell subgroups. By mapping these interactions and differentiation processes, researchers gain insights into how distinct cellular subpopulations coordinate within adipose tissues, which is crucial for maintaining tissue homeostasis and function. Understanding these mechanisms is essential, as dysregulation in adipose cell interactions and differentiation underlies a range of metabolic disorders, including obesity and diabetes mellitus type 2. Furthermore, single-cell transcriptomics holds promising implications for identifying therapeutic targets; by pinpointing specific cell types and gene pathways involved in adipose tissue dysfunction, these technologies pave the way for developing targeted interventions aimed at modulating specific adipose subpopulations. In summary, this review provides a comprehensive analysis of the role of single-cell transcriptomic technologies in uncovering the heterogeneity and functional diversity of adipose tissues.

This study aimed to explore the effects of glutamate (Glu) supplementation on the growth performance, carcass traits, meat quality, composition of amino acids and fatty acids in the longissimus dorsi muscle, and the colonic microbial community of Shaziling pigs. A total of 48 healthy male Shaziling pigs (150 d, 31.56 ± 0.95 kg) were randomly assigned to two groups, and fed a basal diet with no supplement (control group) or supplemented with 1% Glu (Glu group) for 51 d, and 6 pigs per group were finally slaughtered. Glu significantly increased the average daily gain (P = 0.039), lean percentage (P = 0.023), and intramuscular fat (IMF) content (P = 0.015), and decreased the fat percentage (P = 0.021) of Shaziling pigs. In the muscle, Glu increased the concentrations of inosine-5’-monophosphate (P = 0.094), Fe (P = 0.002), Cu (P = 0.052), and monounsaturated fatty acids (MUFAs) (P = 0.024), and decreased the content of C18:2n6 (P = 0.011), n6 polyunsaturated fatty acids (n6 PUFAs) (P = 0.014), and PUFAs (P = 0.014). Moreover, Glu significantly upregulated the mRNA expression of adipogenesis-related genes (FAS, SREBP-1C) (P = 0.032, P = 0.026) and muscle growth-related genes (MyHCⅡb, MyHCⅡx) (P = 0.038, P = 0.019) in the muscle, and increased the relative abundance of Spirochaetota (P < 0.001) and the acetic acid content in the colon (P = 0.039). Correlation analysis indicated that the acetic acid content was positively correlated with the relative Spirochaetota abundance and the IMF content, and a negative trend with the fat percentage of Shaziling pigs. In conclusion, these results indicated that Glu could simultaneously increase the lean percentage and IMF content and decrease the fat percentage of Shaziling pigs, and these beneficial effects may be related to increased colonic Spirochaetota abundance and acetic acid concentrations.

BACKGROUND:Cell-cell crosstalk between myogenic, adipogenic and immune cells in skeletal muscle to regulate energy metabolism and lipid deposition has received considerable attention. The specific mechanisms of interaction between the different cells in skeletal muscle are still unclear. METHODS:Using integrated analysis of snRNA-seq and spatial transcriptome, the gene expression profile of longissimus dorsi (LD) muscle was compared between adult Taoyuan black (TB, obese, native Chinese breed) and Duroc (lean) pigs. RESULTS:TB pig had more intramuscular fat (IMF) deposition (3.91%, p = 0.0244) and higher slow myofiber proportion (17.13%, p < 0.0001) compared with Duroc pig (IMF, 2.38%; slow myofiber, 6.92%) at the age of 180 days. We identified eight cell populations in porcine LD muscle. Five subpopulations of myonuclei and 10 subclusters of fibro/adipogenic progenitors (FAPs) were defined by marker genes. CellChat analysis revealed that communication between immune cells and other cells via the BMP and EGF signalling pathway was only observed in Duroc and not in TB pig. Both snRNA-seq and spatial transcriptome pointed out that FAPs are the important source of secretory proteins. A total of 35 upregulated and 23 downregulated differentially expressed genes (DEGs) were annotated as secretory, one upregulated and 36 downregulated secretory DEGs were identified between TB and Duroc pigs in FAPs by snRNA-seq and FAPs-high regions by spatial transcriptome, respectively. The distribution of FAPs was accompanied by the divergent myofiber-type composition. The expression level of slow myofiber marker gene (MYH7) was higher in both FAPs-high and FAPs-low regions of TB compared with Duroc pig (p < 0.0001), and expression level of fast myofiber maker gene (MYH1) was upregulated in FAPs-high region of Duroc compared with FAPs-high region of TB (p < 0.0001) and FAPs-low region of Duroc pig (p = 0.0002). The metabolic differences of myofibers between TB and Duroc pigs were mainly concentrated in energy, lipid and nitrogen metabolism-related pathway (p < 0.05). The significant correlation (R > 0.4, p < 0.05) between secretory and metabolism-related DEGs with spatial aggregation was verified by regression analysis for random region extraction (area of 25 spots, n = 400) from spatial transcriptome, and we speculated that the alteration of secretory proteins forming the microenvironment might regulate myofiber metabolism via target genes such as IRS1, PLPP1 and SLC38A2. CONCLUSIONS:Our study provides new insights into skeletal muscle microenvironment that contributes to metabolic regulation and new methods and resources to study cell-cell communication in skeletal muscle.

Background: The intestinal development and nutritional needs of piglets after birth are similar to those of human infants. Objectives: This study aimed to investigate the effect of different forms of odd-chain fatty acids (OCFAs) on the growth and intestinal morphology and function of milk replacer-fed piglets, as a model for human infants. Methods: Forty 7-d-old piglets from 8 sows were randomly assigned into 5 groups (n = 8, each from a different litter) and fed sow milk or milk replacers supplemented with different kinds of fats (control fats, docosahexaenoic acid algal oil-, OCFA algal oil-, and OCFA-enriched fats) for 21 d. One-way analysis of variance was performed to compare the milk replacer-fed piglet groups, and unpaired t test was used to compare sow milk- and milk replacer-fed piglets. Results: Milk replacers supplemented with OCFA-enriched fats increased the average daily gain (ADG), ratio of villus height to crypt depth, and protein expression of Ki67, phosphorylated (p)-mTOR, p-S6K1, Occludin, Claudin, and ZO-1 in the selected intestines of piglets and decreased the protein expression of p-ULK1, Parkin, and PINK1 to levels similar to those of the sow milk-fed group (P < 0.05). Conclusion: Overall, milk replacers supplemented with OCFA-enriched fats improved the ADG and the intestinal morphology and function of piglets to levels comparable to those of the sow milk-fed piglets.

Metabolites and metabolism-related gene expression profiles in skeletal muscle change dramatically under obesity, aging and metabolic disease. Since obese and lean pigs are ideal models for metabolic research. Here, we compared metabolome and transcriptome of Longissimus dorsi (LD) muscle between Taoyuan black (TB, obese) and Duroc (lean) pigs at different ages. We defined the “window phase” of intramuscular fat (IMF) deposition in TB pig, which has significantly higher IMF than Duroc pig. Our results displayed discrepant lipid composition and different expression genes (DEGs) enriched in lipid metabolism, and both metabolome and transcriptome analyses revealed stronger energy expenditure and more active amino acid and protein metabolism in Duroc pig. 10 up- and 51 down-regulated biomarker metabolites with age- and breed-specificity were identified. Potential secretory metabolites, including organic acid (fumaric acid, succinate, malic acid, and gamma-aminobutyric acid), amino acid (L-lysine, and L-glutamic acid), lipid (2-hydroxyisovaleric acid, and L-carnitine) were demonstrated a significant correlation with IMF deposition. Our research highlights the huge difference of metabolic spectrum in skeletal muscle between obese and lean model and muscle-derived secretory metabolites might act as an ambassador of intercellular communication to regulate systematic metabolism.

The probiotic bacteria Lactobacillus fermentum ZC529 (L.f ZC529) has been identified from the colon of the Diannan small-ear (DSE) pig, but its intestinal protective function still lacks investigation. Here, we established a dextran sodium sulfate (DSS)-induced intestinal oxidative stress model in both Drosophila and porcine small intestinal epithelial (IPEC-J2) cell lines to explore the anti-oxidative and anti-inflammatory effects of L.f ZC529. The data showed that the intestinal colonization of L.f ZC529 counteracted DSS-induced intestinal oxidative stress and excessive reactive oxygen species (ROS) generation by activation of the CncC pathway, a homology of the nuclear factor erythroid 2-related factor 2 (Nrf2) in mammalian systems. Moreover, L.f ZC529 supplementation prevented flies from DSS-induced intestinal barrier damage, inflammation, abnormal excretory function, and shortened lifespan. Finally, L.f ZC529 also attenuated DSS-induced intestinal injury in the IPEC-J2 cell line by activating the Keap1-Nrf2 signaling and inhibiting the NF-κB signaling pathways. Together, this study unraveled the profound intestinal protective function of L.f ZC529 and provides its potential application as a new antioxidant in improving animal intestinal health as well as in developing a new probiotic in the food industry.

Glutamate (Glu) is a major component of food proteins and is extensively utilized in livestock production. Our previous study demonstrated that dietary Glu supplementation improved the carcass traits of Shaziling pigs. However, the role of Glu in regulating the nutritional quality of pork remains unclear. This study aimed to investigate the effect of Glu on serum biochemical indices, amino acid composition, fatty acid composition, and lipid profiles in pork from Shaziling pigs. A total of 48 Shaziling pigs (150 days old, 31.56 ± 0.95 kg) were randomly divided into a control (Con) group (basic diet), and a Glu group (basic diet supplemented with 1% Glu) for a 51-d feeding trial, and six pigs per group were slaughtered for analysis. Glu had no significant effects on serum biochemical indices and amino acid profiles of the longissimus thoracis (LD) muscle. Fifty distinct fatty acids and 2,124 unique lipid molecules were identified by fatty acid and lipidomics profiling. Glu significantly increased the total fatty acids, particularly polyunsaturated fatty acids (PUFAs) in the LD muscle, and remarkably enhanced the deposition of oleic acid (C18:1n-9) and α-linolenic acid (C18:3n-3). Glu dramatically reduced the levels of monosialo-dihexosylgangliosides (GM3s) and phosphatidylglycerols (PGs), and affected multiple lipid molecules, including phosphatidylcholine (PC) (36:2), PC (18:3e_18:1), phosphatidylethanolamine (PE) (16:0e_21:1), PG (16:0_18:1), and phosphatidylserine (PS) (18:0_18:1). Additionally, Glu induced a reconfiguration of the individual acyl chain composition in the glycerolipids (GL) and glycerophospholipid (GP) pools. Overall, this study elucidated the effects of 1% Glu on the lipo-nutritional quality of LD muscle, offering insights for enhancing pork value in indigenous Chinese pig breeds.

Methionine (Met) is the only sulfur-containing essential amino acid for animals and is the second or third limiting amino acid in swine diets. It plays a role not only in protein synthesis, but also as an important methyl donor to participate in various biochemical reactions. Additionally, Met can be converted into several functional derivatives, such as S-adenosylmethionine (SAM) and homocysteine (Hcy) through which it exerts its biological functions. Specifically, appropriate supplementation with Met or SAM has been shown to provide a wide range of health-promoting effects, particularly in enhancing reproductive performance, improving intestinal morphology, regulating hepatic lipid metabolism, promoting muscle growth, and improving meat quality. In contrast, elevated Hcy levels can increase oxidative stress and inflammation, negatively affecting reproductive performance. Supplemental Met has been widely used in swine production for many years. This review summarizes recent advances in the application of Met and its derivatives in the pig industry, and explores their mechanism of action and optimal dosage as a feed additive, aiming to support the effective development and rational use of Met.

BACKGROUND:We previously demonstrated that Shaziling and Yorkshire pigs differ in growth rate and meat quality. However, the molecular mechanisms responsible for such phenotypic differences remain unclear. In the present study, we performed a transcriptomic analysis of 36 longissimus dorsi (LM) and 36 soleus (SM) muscle samples from Shaziling and Yorkshire pigs at six postnatal stages (30, 60, 90, 150, 210 and 300 days) to explore the differences in postnatal skeletal muscle of Shaziling and Yorkshire pigs. RESULTS:Muscle morphological changes and the number of differentially expressed genes indicated the two stages of 60-90 days and 150-210 days were critical for the muscle growth and development in Shaziling pigs. Genes such as FLNC, COL1A1, NRAP, SMYD1, TNNI3, CRYAB and PDLIM3 played vital roles in the muscle growth, and genes such as CCDC71L, LPIN1, CPT1A, UCP3, NR4A3 and PDK4 played dominant roles in the lipid metabolism. Additionally, in contrast to the LM, the percentage of slow-twitch muscle fibers in the SM of both breeds consistently decreased from 30 to 150 days of age, but there was a significant rebound at 210 days of age. However, the percentage of slow-twitch muscle fibers in the SM of Shaziling pigs was higher than that in Yorkshire pigs, which may be associated with the calcium signaling pathway and the PPARβ/δ signaling pathway. CONCLUSION:The present study detected two critical periods and many functional genes for the muscle growth and development of Shaziling pigs, and showed differences in muscle fiber characteristics between Shaziling and Yorkshire pigs. © 2024 Society of Chemical Industry.

This study was conducted to explore the regulatory mechanism of leucine (Leu) on lipid metabolism of finishing pigs. Twenty-four Duroc × Landrace × Large cross pigs with an average body weight of 68.33 ± 0.97 kg were randomly allocated into 3 treatment groups with 8 replicates per group (1 pig per replicate). The dietary treatments were as follows: control group (CON), 0.25% Leu group and 0.50% Leu group. The experimental period was 42 d. The results showed as follows. 1) Compared with the CON, 0.25% and 0.50% Leu increased (P < 0.01) the average daily gain (ADG), while the average backfat thickness (ABT) and the ratio of feed intake to body weight gain (F:G ratio) were decreased (P < 0.05). 2) In the 0.25% Leu group, the relative mRNA expression levels of sterol regulatory element binding protein-1c (SREBP1c), recombinant fatty acid transport protein 1 (FATP1), chemerin and peroxisome proliferator-activated receptor γ (PPARγ) were decreased but the level of fatty acid binding protein 4 (FABP4) and fatty acid translocase (FAT/CD36) were increased in backfat tissue. In the 0.25% Leu group, the protein levels of p-rictor, p-raptor, p-eIF4E-binding protein1 (p-4EBP1), p-silent mating type information regulator 2 homolog 1 (p-SIRT1) and acetylation ribosome s6 protein kinase 1 (Ac-S6K1) were increased (P < 0.05). 3) Compared to the CON, the diversity of gut microbiota in the 0.25% Leu group was increased. Principal component analysis showed that the relative abundance of Bacteroidetes, Lactobacillus and Desulfovibrio was higher in the 0.25% Leu group than the CON, but the relative abundance of Firmicutes, Treponema and Shigella was lower than in the CON (P < 0.05). 4) Four different metabolites were screened out from the serum of finishing pigs including allolithocholic acid (alloLCA), isolithocholic acid (isoLCA), ursodeoxycholic acid (UDCA) and hyodeoxycholic acid (HDCA), which correlate to various degrees with the above microorganisms. In conclusion, Leu could promote adipose tissue lipolysis of finishing pigs through the mTOR-SIRT1 signaling pathway, and S6K1 is acetylated at the same time, and the interaction between gut microbiota and bile acid metabolism is also involved.

Leucine is involved in promoting fatty acid oxidation and lipolysis, mediating lipid metabolism and energy homeostasis, thus it has been widely used in livestock production. However, the effects of leucine on fat deposition and nutrition in Shaziling pigs remain unclear. A total of 72 Shaziling pigs (150 days old, weight 35.00 ± 1.00 kg) were randomly divided into 2 groups and fed with basal diet (control group) or basal diet containing 1% leucine (leucine group) for 60 days. The results showed that leucine significantly increased the average daily feed intake but decreased the ratio of feed to gain (P < 0.05), increased the loin muscle area and serum glucose content (P < 0.05) of Shaziling pigs. Besides, leucine regulated the re-distribution of fatty acids from adipose tissue to muscle as it significantly increased the contents of C18:1n-9 and C22:6n-3 (DHA) in the longissimus thoracis while decreased the contents of C22:5n-3 (DPA), C20:5n-3 (EPA), and DHA in the adipose tissue of Shaziling pigs (P < 0.05). Lipidomic analysis showed that the contents of phosphatidylethanolamines (PEs), cardiolipins (CLs), and phosphatidylglycerols (PGs) in the longissimus thoracis and the contents of lysophosphatidylethanolamines (LPEs), ceramides (Cers), phosphatidylinositols (PIs) in adipose tissue of Shaziling pigs were decreased in leucine group (P < 0.05). Collectively, this study clarified that dietary addition of 1% leucine have a better effect on growth performance and the deposition of beneficial fatty acids in the muscle of Shaziling pigs, which is conductive to the production of high quality and healthy pork. In addition, leucine altered the lipid composition of muscle and fat in Shaziling pigs. The related results provide a theoretical basis and application guidance for regulating fat deposition in Shaziling pigs, which is important for the healthy breeding of Shaziling pigs.

We previously demonstrated that lipopolysaccharide (LPS) injection-induced immune stress could impair muscle growth in weaned piglets, but the precise mechanisms behind this remain elusive. Here, we found that chronic immune stress induced by LPS resulted in a significant reduction of 36.86% in the total muscle mass of piglets at 5 d post-treatment compared with the control group. At 1 d, prior to muscle mass loss, multiple alterations were noted in response to LPS treatment. These included a reduction in the abundance of Bacteroidetes, an increase in serum concentrations of pro-inflammatory cytokines, compromised mitochondrial morphology, and an upregulation in the expression of dynamin-related protein 1 (Drp1), a critical protein involved in mitochondrial fission. We highlight a strong negative correlation between Bacteroidetes abundance and the levels of serum pro-inflammatory cytokines, corroborated by in vivo intervention strategies in the musculature of both pig and mouse models. Mechanistically, the effects of Bacteroidetes on inflammation and muscle mass loss may involve the signaling pathway of the tauro-β-muricholic acid-fibroblast growth factor 15. Furthermore, the induction of overexpression of inflammatory cytokines, achieved without LPS treatment through oral administration of recombinant human IL-6 (rhIL-6), led to increased levels of circulating cytokines, subsequently causing a decrease in muscle mass. Notably, pre-treatment with Mdivi-1, an inhibitor of Drp-1, markedly attenuated the LPS-induced elevation in reactive oxygen species levels and rescued the associated decline in muscle mass. Collectively, these data indicate that LPS-induced muscle mass loss was linked to the reduction of Bacteroidetes abundance, increased inflammation, and the disruption of mitochondrial morphology. These insights offer promising avenues for the identification of potential therapeutic targets aimed at mitigating muscle mass loss.

The accumulation of excess reactive oxygen species (ROS) can lead to oxidative stress (OS), which can induce gene mutations, protein denaturation, and lipid peroxidation directly or indirectly. The expression is reduced ATP level in cells, increased cytoplasmic Ca2+, inflammation, and so on. Consequently, ROS are recognized as significant risk factors for human aging and various diseases, including diabetes, cardiovascular diseases, and neurodegenerative diseases. Mitochondria are involved in the production of ROS through the respiratory chain. Abnormal mitochondrial characteristics, including mitochondrial OS, mitochondrial fission, mitochondrial fusion, and mitophagy, play an important role in various tissues. However, previous excellent reviews focused on OS-induced diseases. In this review, we focus on the latest progress of OS-induced mitochondrial dynamics, discuss OS-induced mitochondrial damage-related diseases, and summarize the OS-induced mitochondrial dynamics-related signaling pathways. Additionally, it elaborates on potential therapeutic methods aimed at preventing oxidative stress from further exacerbating mitochondrial disorders.

This study aimed to investigate the effects of dietary Eucommia ulmoides leaf extract (ELE) on meat quality, antioxidant capacity, and lipid metabolism in finishing pigs. A total of 240 “Duroc × Landrace × Yorkshire” crossbred pigs with an initial weight of 74.70 ± 0.77 kg were randomly assigned to two groups: control group and 0.2% ELE group, with each group containing 10 replicates of 12 pigs per pen (half barrows and half gilts). The data showed dietary 0.2% ELE supplementation did not affect growth performance but tended to reduce the backfat thickness of the finishing pigs (p = 0.07). ELE diets increased pH value (p < 0.05) and meat color score (p = 0.01) and decreased 45 min L* value (p < 0.05), 24 h L* value (p = 0.01), pressurization loss (p = 0.01), and 24 h drip loss (p < 0.05) in longissimus dorsi (LD) muscle, accompanied by an increased (p < 0.05) proportion of monounsaturated fatty acids (MUFA) and decreased polyunsaturated fatty acids (PUFA) (p = 0.06) and n-6/n-3 PUFA ratio (p = 0.05) compared to controls. In addition, ELE supplementation increased inosine monophosphate (IMP) (p = 0.01), sweet amino acids (AAs) (p < 0.05), and total free AA content (p = 0.05) in LD. Meanwhile, increased activity of glutathione peroxidase (p < 0.05) and superoxide dismutase (p < 0.01) in both serum and LD muscle and decreased malondialdehyde content (p < 0.01) in LD muscle were detected with ELE treatment. Moreover, pigs fed ELE had a higher total protein (p < 0.01), albumin (p < 0.05), and high-density lipoprotein cholesterol (p < 0.05) and a lower total cholesterol (p < 0.01) and triacylglycerols (p = 0.06) in serum. Consistently, significant effects of dietary ELE were observed on the relative mRNA expression of lipid metabolism in the backfat and the LD muscle, respectively. ELE attenuated lipogenic processes in backfat, decreasing the relative expression of acetyl-CoA carboxylase and upregulating the relative expression of adipose triacyl glyceride lipase, carnitine palmitoyl transferase 1B, and fatty acid-binding protein 4 (p < 0.05). ELE also decreased the relative expression of CCAAT/enhancer-binding protein α (p < 0.05), fatty acid translocase (p < 0.05), carnitine palmitoyl transferase 1B (p < 0.01), and adipose triacyl glyceride lipase (p < 0.05) in LD muscle (p < 0.05). More specifically, lipogenesis appeared to be inhibited in both LD muscle and backfat, with the difference being that lipolysis was enhanced in backfat and inhibited in LD muscle. In conclusion, dietary ELE supplementation can potentially enhance carcass traits, sensory quality, and nutritional value of pork without negatively affecting intramuscular fat content. The underlying mechanism for these positive effects may be linked to the alterations in lipid metabolism and increased antioxidant capacity induced by ELE.