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), n-6 polyunsaturated fatty acids (n-6 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.

The present study investigated whether replacing dietary rice straw with peanut vine (PEV) and Broussonetia papyrifera silage (BPS) reduces the use of soybean meal and explored its effects on the growth performance, blood biochemical indicators, serum metabolomics, and meat quality of fattening bulls. Forty-five Simmental crossbred bulls (initial body weight = 484.29 ± 8.49 kg) were randomly allotted into three dietary treatment groups (n = 15): (1) CON, 5% rice straw (DM basis); (2) PEV, 5% peanut vine (DM basis); and (3) BPS, 5% B. papyrifera silage (DM basis). The remaining roughage for all three treatment groups was supplemented with 25% corn silage (DM basis). The experiment lasted for 123 d, with the first 14 d serving as an adaptive period. Throughout the experiment, dietary BPS decreased the average daily dry matter intake (P < 0.001) and feed cost (P < 0.001). Serum metabolomics analysis showed that PEV affected the phenylalanine, tyrosine, and tryptophan biosynthesis pathways (P = 0.021) and lysine degradation pathway (P = 0.042), whereas BPS affected the phenylalanine, tyrosine and tryptophan biosynthesis pathways (P = 0.004), lysine degradation pathway (P = 0.012), and serotonergic synapse pathway (P < 0.001). Regarding meat quality, the redness (P = 0.025) and hue angle values (P < 0.001) of the longissimus dorsi muscle were lower in the BPS group than in the CON and PEV groups. The yellowness of the longissimus dorsi muscle was lower in the BPS group than in the PEV group (P = 0.024), and the shear force was lower in the PEV group than in the BPS group (P = 0.014). However, lysine content in beef was higher in the BPS group than in the CON group (P = 0.005). In conclusion, replacing rice straw with PEV and BPS reduced the use of soybean meal but had no adverse effects on growth performance. BPS affected the amino acid metabolism of bulls, thus decreasing feed intake and increasing the lysine content in meat. The PEV group showed better meat quality than the BPS group.

Improving the nutrient utilization efficiency of ruminants is of utmost significance for both economic and environmental benefits. Optimizing dietary protein levels represents a key nutritional strategy to enhance ruminant growth performance and reduce nitrogen emissions. In a 63-day experiment, 24 healthy Hulunbuir lambs (initial weight 17.1 ± 2.0 kg, 2.5 months old) were subjected to three treatments: a low-protein diet (LP; crude protein of 78.4 g/kg dry matter [DM]), a medium-protein diet (MP; crude protein of 112.0 g/kg DM), and a high-protein diet (HP; crude protein of 145.6 g/kg DM), with 8 lambs in each treatment (4 males and 4 females). Lambs in the MP treatment presented greater daily weight gain and feed conversion ratio than those in the HP treatment (P < 0.05, quadratically). Compared with the LP treatment, the MP treatment resulted in greater crude protein digestibility (P < 0.001, quadratically) and acid detergent fiber digestibility (P = 0.022, quadratically). In the serum, the urea nitrogen level increased quadratically with increasing dietary protein levels (P < 0.001), while the LP treatment exerted the highest concentrations of glutamate, glycine, alanine, and histidine (P < 0.05, quadratically). The ammonia nitrogen concentrations in the rumen and colon increased quadratically with increase in dietary protein levels (P < 0.05). The HP treatment increased the molar concentrations of isobutyrate and isovalerate in the rumen and colon (P < 0.05, quadratically). In contrast, the LP treatment decreased the molar proportion of acetate (P = 0.007, quadratically) and increased the molar proportion of butyrate (P < 0.001, quadratically) in the colon. The microbial diversity and structure were significantly altered by dietary protein level intervention across all gastrointestinal regions. The rumen of the MP treatment was enriched with fiber-degrading bacteria Fibrobacter_succeinogenes and starch-degrading bacteria Selenomonas_ruminantium. The colon in the LP treatment harbored microbial biomarkers including Escherichia spp. and Lactobacillus amylovorus, and the colon in the MP treatment was characterized by the enrichment of Solibacillus_cecembensis. These findings suggest that the MP diet with a crude protein content of 112.0 g/kg DM improved the growth performance and nutrient efficiency of lambs, which was achieved via the involvement of the gastrointestinal microbiota.

Multiple stressors are believed to deteriorate production performance and cause substantial economic losses in commercial poultry farming. Folic acid (FA) is an antioxidant compound that can improve oocyte function and regulate gut microbiota composition. The current study was conducted to investigate the role of FA in alleviating stress and improving production performance. Sixty Hyline Brown laying hens at 21 weeks of age were randomly divided into three groups, with 10 replicates in each group and each replicate containing two chickens. Each group received basic diet and saline injection (Con group), basic diet with dexamethasone (DXM) injection (DXM group), or basic diet supplemented with FA (13 mg/kg in the premix) with DXM injection (FA group). The feeding trial lasted five weeks. Birds in the DXM and FA groups receiving subcutaneous DXM injections at a dosage of 4.50 mg/kg per day during the first seven days of the trial. Results showed that the levels of corticosterone, triglyceride, total cholesterol, and malondialdehyde in serum were significantly increased in the DXM group (P < 0.05), while the concentrations of FA and 5-methyltetrahydrofolate were decreased in the DXM group (P < 0.05). Laying hens in the DXM group had lower laying rates and egg quality, including egg weight, eggshell thickness, eggshell strength, albumen height, and Haugh units (P < 0.05). Conversely, FA alleviated these negative impacts. Through transcriptome analysis, a total of 247 and 151 differentially expressed genes were identified among the three groups, and 32 overlapped genes were further identified. Moreover, 44 and 59 differential metabolites were influenced by DXM and FA, respectively. Kyoto Encyclopedia of Genes and Genomes enrichment from the transcriptome and metabolomics showed that the reduced production performance may be due to the disturbance of oocyte production, calcium metabolism, and oxidative stress. Analysis of 16S rRNA gene amplicon sequences revealed the differential microbial composition and potential functional changes among the different groups. LEfSe analysis showed that Mucispirillum and Nautella were the predominant bacteria in the DXM group, while Clostridium was the predominant bacteria in the FA group. Functional prediction demonstrated that stressors enhanced fatty acid biosynthesis, while betaine biosynthesis and retinol metabolism were elevated in the FA group. Dietary FA reversed the elevated levels of bile acids (BA), including cholic acid, taurodeoxycholic acid, and taurochenodeoxycholic acid (P < 0.05). The DXM group showed an overall decrease in short-chain fatty acids (SCFA), but FA restored the concentrations of acetic acid, propionic acid, and isobutyric acid (P < 0.05). In conclusion, this study reveals that dietary FA can alleviate the degradation of production performance caused by stress through improving circulating antioxidant capacity, maintaining intestinal microbiota homeostasis, and regulating SCFA and BA biosynthesis. Thus, highlighting the prominent role of gut microbe-host interactions in alleviating multi-stresses.

It has been found that thymol (Thy) and rosmarinic acid (Ros-A) improve the growth performance of piglets and relieve intestinal inflammation in animals. The effects of Thy and Ros-A separately or in combination (Thy × Ros-A) on the intestinal function and health of piglets challenged with Escherichia coli K88 (E. coli K88) were investigated. A total of 30 piglets aged 21 d were assigned to 5 groups (n = 6). The control (Con) and K88 groups piglets received a basal diet, while the Thy, Ros-A, and Thy × Ros-A groups were fed a basal diet supplemented with 500 mg/kg Thy, 500 mg/kg Ros-A, and 250 mg/kg Thy + 250 mg/kg Ros-A, respectively. On the 19th and 20th day, piglets in the K88, Thy, Ros-A, and Thy × Ros-A groups were orally administered 10 mL of phosphate-buffered saline (PBS) containing approximately 1 × 10⁹ CFU/mL of E. coli K88, while the Con group received an equal volume of PBS. The results showed that the Thy × Ros-A treatment reduced the damage to ileal villi induced by the E. coli K88 challenge, leading to longer villi in the ileum (P < 0.05). Thy and Ros-A modulated the composition of the ileal microbiota. Compared to the K88 group, the Thy × Ros-A group had a higher abundance of Lactobacillus and Romboutsia, while Escherichia-Shigella and Desulforvibrio were lower (P < 0.05). Additionally, the Thy × Ros-A group showed elevated levels of gene and protein expressions for zonula occludens-1, occludin, and claudin-1 compared to the K88 group (P < 0.05). In conclusion, combining Thy and Ros-A reduced ileal damage and relieved the inflammation in weaned piglets challenged with E. coli K88 by regulating intestinal microflora and improving barrier function.

The objectives of the current study were to compare the difference between standardized ileal digestibility (SID) and standardized total tract digestibility (STTD) of phosphorus (P) in pigs using published data and investigate the factors that affect the hindgut disappearance of P in pigs. A total of 156 observations from 32 experiments that determined the apparent ileal digestibility and total tract digestibility of P in pigs were collected. The SID and STTD of P were calculated by accounting for basal endogenous losses of P. Standardized hindgut disappearance (SHD) of P was determined by subtracting the SID of P from the STTD of P. The Chi-square test was performed to investigate the association between SHD of P and categorical variables, including the use of phytase, the use of inorganic P sources, the use of corn-soybean meal-based diets, and body weight (BW) of pigs. To determine the effects of the SID of P on the SHD of P, a linear equation for the SHD of P was developed using the SID of P as an independent variable. The BW of pigs ranged from 10.0 to 104.8 kg and the SHD of P ranged from −22.8% to 39.8%. The STTD of P was greater than the SID of P (47.1% vs. 49.7%; P = 0.019). Based on the Chi-square analysis, the supplementation of inorganic P sources tended to result in a higher occurrence of a positive value for the SHD of P (P = 0.079). In addition, the occurrence of a positive value in the SHD of P was lower when the BW of pigs was below 30 kg. However, as the BW of pigs increased, the occurrence of a positive value in the SHD of P increased (P = 0.061). A regression analysis of the SHD of P against the SID of P in pigs indicated that the SHD of P decreased as the SID of P increased in pigs (r² = 0.17; P < 0.001). In conclusion, the STTD of P is greater than the SID of P in pigs, and the SHD of P depends on the diet composition, the amount of P entering the large intestine, and the BW of the pigs.

This study investigated the effect of peroxidized lipids on piglets' growth performance, intestinal morphology, inflammatory reactions, oxidative stress in the liver, duodenum, jejunum, ileum, and colon, and ileal microbiota. Twenty piglets (Duroc × [Landrace × Yorkshire]; age = 21 d old, BW = 6.5 ± 1 kg) were randomly assigned to two groups with 10 replicates per group and one piglet per replicate. The control group was fed 6% fresh soybean oil and the peroxidized soybean oil (PSO) group fed 6% PSO. The experimental feeding period lasted 24 d. The study found no impact on ADFI, ADG and gain to feed ratio (P > 0.05). However, the PSO group increased the diarrhea index and the serum levels of lactate dehydrogenase triglycerides, cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol (P < 0.05), along with decreased concentrations of alanine aminotransferase and blood urea nitrogen (P < 0.05). For oxidative enzymes, PSO increased the concentration of F2-isoprostane in urine (P = 0.032), malondialdehyde (MDA) in the duodenum (P = 0.001) and jejunum (P = 0.004), decreased thiobarbituric acid reactive substances (TBARS) in the liver (P = 0.001) but increased TBARS in duodenum (P = 0.001), and carbonylated proteins in the duodenum (P = 0.003). For antioxidant enzymes, PSO decreased superoxide dismutase (SOD) in the liver (P = 0.001), colon (P = 0.002), and jejunum (P = 0.015), along with glutathione peroxidase (GSH-Px) in the liver (P = 0.008) and NAD(P)H:quinone oxidoreductase 1 (NQO1) in ileum (P = 0.001). For inflammatory reactions, PSO increased interleukin (IL)-1β concentrations in the duodenum and colon, and IL-10 in the jejunum, while decreasing IL-4 concentration in the duodenum (P < 0.05). For intestinal morphology and ileal microbiota, PSO increased ileal crypt depth, while decreasing the crypt-to-villus ratio (P < 0.05). Peroxidized soybean oil increased the relative abundance of Prevotella, Clostridium_sensu_stricto_1, Clostridium_sensu_stricto_6, Pasteurella and Klebsiella (P < 0.05). In conclusion, this study revealed that PSO worsened diarrhea, increasing the ileal crypt depth and the relative abundance of harmful microbiota, and induced oxidative stress and inflammation in the intestines and liver, primarily in the jejunum and ileum.

This study aimed to evaluate the effects of dietary geniposide supplementation on growth performance, lipid metabolism, health status, and ammonia stress resistance in turbot (Scophthalmus maximus). Four hundred fifty fish were randomly allocated into 5 treatments with triplicate tanks (30 fish per tank). They were hand-fed to apparent satiety for 56 d with a basal diet (GP0) or diets containing 100, 200, 400, and 800 mg/kg geniposide (termed as GP100, GP200, GP400, GP800, respectively). After the conclusion of the feeding trial, the fish were exposed to ammonia stress for 96 h. The results showed that the growth performance were not affected by geniposide (P > 0.05). Dietary supplementation with geniposide decreased crude lipid in viscera without liver, subcutaneous adipose tissue (SAT), and the liver, as well as triglyceride concentrations in plasma, the liver and SAT (P < 0.05). Dietary supplementation with 400 and 800 mg/kg geniposide significantly down-regulated lipogenesis-related gene expression, as well as fatty acid uptake-related gene expression, while significantly up-regulated triglyceride secretion-related gene expression in the liver compared with the control group (P < 0.05). The GP800 group exhibited a significant reduction in plasma malondialdehyde contents compared with the control group, while both the GP200 and GP800 groups showed a significant increase in plasma complement C3 activities (P < 0.05). Furthermore, there was a notable enhancement in plasma lysozyme and total superoxide dismutase levels in the geniposide supplemented groups compared to the control group (P < 0.05). Additionally, a significant decrease in the mRNA level of pro-inflammatory cytokine and a remarkable increase in the mRNA expression of anti-inflammatory cytokines were discovered in geniposide supplemented groups relative to the control group (P < 0.05). Cumulative survival rates after ammonia stress in the GP400 and GP800 groups were statistically higher than that in the control group (P < 0.05). In conclusion, dietary geniposide supplementation could reduce lipid deposition in turbot by regulating lipid metabolism and transportation, and remarkably enhance immunity, antioxidant ability, and resistance to ammonia stress in turbot. Based on the quadratic regression analyses, the optimal concentrations of geniposide were estimated to be 545.21 to 668.41 mg/kg feed.