The intensifying global warming may increase the impact of heat stress on the dairy industry. Our previous study showed that chromium yeast (CY) alleviated the negative effects of heat stress and improved the lactation performance by increasing milk protein content and yield in mid-lactation dairy cows. This study further investigated whether the increased milk protein after CY supplementation results from the promotion of microbial crude protein (MCP) synthesis by regulating rumen microorganisms and amino acid metabolites. Twelve heat-stressed dairy cows were divided into two treatment groups: one with CY supplementation (0.36 mg Cr/kg DM) and the other without CY supplementation. Samples were collected after eight weeks of formal experiment in a hot summer with the mean temperature-humidity index of 79.0 ± 3.13. Dietary CY supplementation did not affect rumen pH, total volatile fatty acid, acetate, propionate, isobutyrate, butyrate, isovalerate, and valerate, but increased ruminal MCP concentration (P < 0.05). Simultaneously, the alpha or beta diversity of rumen microbial bacteria were not influenced by CY supplementation. At genus level, supplementation with CY increased the relative abundances of Olsenella, Lachnospiraceae_UCG-002, and Shuttleworthia (P < 0.05) and decreased those of Enterobacter, Escherichia-Shigella, Oribacterium, and Bacteroidetes_BD2-2 (P < 0.05). There were 17 up-regulated and 57 down-regulated differential metabolites in the CON and CY groups. The partial least-squares discriminant analysis (PLS-DA) and orthogonal partial least-squares discriminant analysis (OPLS-DA) scores clearly distinguished the two groups. Chromium yeast supplementation reduced the concentrations of D-(+)-proline, DL-glutamic acid, DL-lysine, Gly-l-pro, L-(−)-serine, L-(+)-alanine, and L-(+)-aspartic acid (P < 0.05) in the ruminal fluid, which were involved in arginine biosynthesis (P = 0.029), glutathione metabolism (P = 0.047), lysine degradation (P = 0.069), and D-amino acid metabolism (P = 0.084). Spearman correlation analysis showed that milk protein content was positively correlated with MCP and negatively correlated with amino acid concentrations in the ruminal fluid (P < 0.05). Collectively, CY supplementation promoted the utilization of amino acids by rumen microorganisms to synthesize MCP, thereby increasing milk protein content and yield in heat-stressed dairy cows.

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.

Methionine (Met) metabolism is vital for one carbon metabolism, redox status and fetal development. Hence, this study investigated the effects of different levels and sources of Met on maternal metabolism, anti-oxidative capacity and fetal survival in pregnant sows. Forty primiparous sows were assigned to the following four groups: control group (basal diet, CON), 1.5S-OHMet group (supplemented methionine hydroxy analogue [OHMet] at 1.5 g/kg diet), 3.0S-OHMet group (supplemented OHMet at 3.0 g/kg diet), and 3.0S-Met group (supplemented L-Met at 3.0 g/kg diet) (n = 10). The trial lasted from day 60 of gestation to the farrowing day. Maternal 1.5S-OHMet consumption had the lowest stillborn ratio and the highest serum glucose levels during farrowing. Further analysis revealed that dietary 1.5S-OHMet consumption elevated the serum contents of glucose-6-phosphate, citric acid, butyric acid, malic acid, 3-methyladenine, 1-methyladenosine, ferulic acid and salicylic acid, but reduced the serum contents of succinic acid, oxoglutaric acid, 9(S)-hydroperoxylinoleic acid, 13(S)-hydroperoxy-octadecatrienoic acid, uric acid and urea nitrogen when compared to contents observed in the 3.0S-OHMet and 3.0S-Met groups (P < 0.05). Serum metabolomics analysis was conducted to determine the enriched differential metabolites and an enrichment analysis was performed using Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis. The results showed that the enriched metabolites were mainly associated with central carbon metabolism, amino acid metabolism, lipid metabolism, and nucleotide metabolism. Moreover, maternal 3.0S-OHMet or 3.0S-Met consumption upregulated the trans-methylation pathway by elevating the S-adenosyl-methionine (SAM) level and the ratio of SAM to S-adenosyl-homocysteine (P < 0.05) at day 114 of gestation, while increasing homocysteine concentration (P < 0.001). However, compared to the 3.0S-Met group, maternal 3.0S-OHMet consumption elevated fetal survival and glutathione peroxidase (P < 0.05). Thus, this study provided new insights into the mechanisms through which sows fed with a 1.5S-OHMet diet during mid-to late-gestation period had high fetal survival, such as improvements in maternal amino acid, nucleotide and glycolipid metabolism.

This research explored the protective impact of bamboo leaf flavonoids (BLF) in diquat (DQ) stressed broilers; providing insight of antioxidant, immune response and intestinal barrier function. This experiment consisted of two parts. In the first, 240 chicks were allotted to 2 groups with 8 replicates and 15 chicks per replicate. Treatments consisted of a basic feed (control group, CON) and the basic feed plus 1000 mg/kg BLF (BLF group, BLF) for 28 d, respectively. Then, following the conclusion of the first part, 16 healthy broilers were selected from the CON group and the BLF group. They formed the second part of the experiment, and were allotted to 4 treatments with 8 broilers each: CON-no stress (CON-NS) group, CON-DQ group, BLF-NS group and the BLF-DQ group. Broilers were separately injected intraperitoneally with DQ solution at 40 mg/kg body weight or the same dose of phosphate buffer saline. The results revealed adding BLF to diet reduced the ratio of feed to weight gain of broilers compared to the basic feed group (P = 0.021). In comparison to the CON-NS group, BLF improved the levels of serum and jejunal mucosa total antioxidant capacity, immunoglobulin M, serum catalase, immunoglobulin A, interleukin 10, jejunal mucosa interleukin 4, cecal butyric acid, valeric acid, isobutyric acid, isovaleric acid, upregulated zonula occludens-1 (ZO-1), occludin (OCLN) and claudin-1 (CLDN1) expressions, and reduced the levels of jejunal mucosa malondialdehyde (MDA), interleukin 1β, interleukin 6 and serum diamine oxidase (P < 0.05). Diquat stress elevated the contents of serum MDA, D-lactate, jejunal mucosa tumor necrosis factor α, reactive oxygen species and unclassified_f_Lachnospiraceae relative abundance, downregulated ZO-1, OCLN and CLDN1 expressions, and reduced Sobs, Chao and Ace indices (P < 0.05). Compared with CON-NS group, the concentration of isovaleric acid in the BLF-DQ group was higher (P < 0.05). In conclusion, by establishing a DQ stress injury model, it was elucidated that BLF may enhance antioxidant capacity, strengthen immunity, regulate volatile fatty acid contents, improve intestinal morphology, microbiota and other intestinal barrier functions, so as to mitigate the injury induced by oxidative stress in broilers.

Heat stress can lead to decreased feed intake, apoptosis of mammary epithelial cells, and decreased milk yield and quality. Selenium is an important element in the composition of at least 25 selenoproteins. Hydroxy-selenomethionine (HMSeBA) is a novel organic selenium that has been shown to have a better deposition effect. However, whether HMSeBA alleviates damage to the mammary gland blood-milk barrier caused by heat stress and how this affects the performance of dairy cows remain largely unexplored. Therefore, 32 healthy Holstein cows with similar gestation days (150.41 ± 20.07 d), milk yield (36.15 ± 3.02 kg) and parity (3.25 ± 0.51) were selected and randomly divided into two total mixed rations with different selenium (Se) sources: sodium selenite (SSe) and HMSeBA. This study evaluated the outcomes of HMSeBA on antioxidant capacity, immunity, and blood-milk barrier damage in dairy cows during heat stress by collecting the samples of blood, rumen fluid and mammary gland biopsy. The experiment was conducted over 35 d, including a 5-day pre-feeding period and a 30-day experimental period. The temperature and humidity index (THI) were all above 80 throughout the experiment period. The results showed that HMSeBA decreased the respiratory rate (P < 0.001) and the content of inflammatory cytokines in the serum and increased the content of immune factors and antioxidant capacity (P < 0.05). In addition, HMSeBA reduced the expression of inflammatory cytokines and heat shock proteins in mammary gland (P < 0.05). Hematoxylin-eosin-stained pathological sections showed massive thickening of acinar walls and severe destruction of glandular structures in the SSe group, but the structure of the acinar mammary gland in the HMSeBA group was intact. Furthermore, HMSeBA promoted the expression of the phosphatidylinositol 3-kinase (PI3K, P < 0.001)/protein kinase B (AKT, P = 0.011)/mammalian target of rapamycin (mTOR, P = 0.008) pathway and improved the expression of zonula occludens-1 (ZO-1, P = 0.014) and occluding (OCLN, P = 0.012) in the mammary gland, suggesting less damage caused by heat stress to the blood-milk barrier. Our results demonstrated that HMSeBA can improve the antioxidant capacity and immunity of dairy cows and the expression of tight junction proteins in mammary gland to help alleviate the blood-milk barrier damage by heat stress, which could reduce the damage of heat stress on milk yield.

Bacteroides fragilis (B. fragilis), a crucial commensal bacterium within the gut, has shown connections with hepatic lipid metabolism and inflammation regulation. Nonetheless, the role of B. fragilis in the progression of fatty liver hemorrhagic syndrome (FLHS) remains unknown. This study aims to explore the ameliorative effects of B. fragilis on FLHS in laying hens, as well as its underlying mechanisms. This is the first study to employ a chicken FLHS model, combining microbiomics and oxylipin metabolomics to investigate the mechanism of action of intestinal symbiotic bacteria. Exp. 1: 40 laying hens at 25 weeks old were randomly divided into five treatment groups (eight replicates per group and one hen per replicate), including the control group (basal diet), the high-energy and low-protein (HELP) group, and the HELP group with three different levels (10⁸, 10⁹, and 10¹⁰ CFU) of B. fragilis. Exp. 2: 18 chickens at 25 weeks old were randomly divided into three treatment groups (six replicates per group and one hen per replicate) including the control group (basal diet), the model group (HELP diet), and the arachidonic acid (AA) group (HELP diet with 0.3% AA). The experiment period of Exp. 1 and Exp. 2 were 8 weeks. B. fragilis significantly improved body weight of seventh week (P = 0.006), liver lipid degeneration, blood lipid levels (triglycerides, cholesterol, and low-density lipoprotein cholesterol; P < 0.05), and liver function (alanine aminotransferase and aminotransferase; P < 0.05) in laying hens. B. fragilis downregulated the expression of lipid synthesis-related genes fatty acid synthase, acetyl-CoA carboxylase, and liver X receptor α, and inflammation-related genes tumor necrosis factor α, interleukin (IL)-1β, IL-6, and IL-8 in the liver of FLHS-affected hens (P < 0.05), while upregulating the expression of lipid oxidation-related genes carnitine palmitoyl transferase-1, peroxisome proliferator activated receptor (PPAR) α, and PPARγ (P < 0.05). The in-depth analysis indicated alterations in oxylipin pathways triggered by B. fragilis, as evidenced by changes in the expression of pivotal genes arachidonate 15-lipoxygenase, arachidonate 5-lipoxygenase (P < 0.05), subsequently causing modifications in relevant metabolites. This included a decrease in pro-inflammatory substances such as 15-oxoETE (P = 0.004), accompanied by an increase in AA (P = 0.008). B. fragilis regulated the homeostasis of intestinal flora by increasing the abundance of Bacteroides and decreasing the abundance of Succinatimonas and Faecalicoccus (P < 0.05). The integrated analysis revealed a robust positive correlation between Bacteroides abundance and AA levels (P = 0.007). This relationship was corroborated through in vitro experiments. Subsequently, the beneficial effect of AA in mitigating FLHS was confirmed in laying hens with FLHS, further supported by reverse transcription-polymerase chain reaction analysis demonstrating gene expression patterns akin to B. fragilis intervention. This study demonstrated that B. fragilis exerts an anti-FLHS effect through modulation of oxylipin metabolism and gut microbiota stability, with a pivotal role played by AA.

Grape seed proanthocyanidin (GSP) is a type of plant polyphenol with a wide variety of biological activities, such as antioxidant properties. This study investigated the effects of GSP supplementation on growth performance and meat quality in growing-finishing pigs. A total of 180 pigs (with an initial average body weight of 30.37 ± 0.66 kg) were randomly assigned to five treatments: a control diet or a control diet supplemented with GSP at 15, 30, 60, and 120 mg/kg. Each treatment group comprised six replicate pens (6 pigs per pen). Results showed that GSP supplementation linearly increased the average daily gain (P = 0.048) and quadratically decreased the feed intake to gain ratio (P = 0.049) with the lowest values at 30 and 60 mg/kg GSP. Serum concentrations of immunoglobulins (Ig) (IgA, IgG, IgM), total antioxidative capacity, catalase, and total superoxide dismutase were elevated with the peak levels at 30 mg/kg GSP (P < 0.05). Serum glutathione peroxidase increased and malondialdehyde decreased quadratically (P < 0.05), with peak and trough levels at 120 and 60 mg/kg GSP, respectively. The GSP also improved dressing percentage and muscle redness (a^*_{45 min}) with optimal levels at 30 and 60 mg/kg (P < 0.05). Additionally, GSP supplementation quadratically reduced the muscle yellowness (b^*_{24 h}) and shear force (P < 0.05), with the lowest values at 120 mg/kg. The expression level of myosin heavy chain I in muscle was quadratically increased with maximum expression at 30 and 60 mg/kg (P = 0.015). Furthermore, the expression levels of fatty acid synthase, phosphoenolpyruvate carboxykinase (PEPCK), and glucokinase in the muscle were decreased quadratically (P < 0.05) with the lowest values at 120 mg/kg. Additionally, GSP supplementation at 60 mg/kg upregulated the expression of hepatic hormone-sensitive triglyceride lipase and PEPCK (P < 0.05). These results suggest that GSP enhances carcass characteristics and meat quality in growing-finishing pigs, potentially through improved antioxidative capacity, modified muscle fiber type distribution, and altered glucose-lipid metabolism in muscle and liver.

During the growing period, the gastrointestinal tract of layer pullets is not yet well developed and may be susceptible to dietary energy level. The energy level and composition might impact the intestinal energy metabolism of layer pullets. To test this hypothesis, a total of 480 “Jing Tint 6” layer pullets were used in an 8-week study and allocated to 4 groups, each consisting of 8 replicates, with 15 birds per replicate. Pullets were treated with low or high starch:fat ratios (LS, 10:1; HS, 20:1) in a 2 × 2 factorial arrangement with regular energy (RE, 11.85 and 11.68 MJ/kg for birds from 6 to 10 weeks of age and 11-14 weeks of age, respectively) or low energy (LE, 0.55 MJ/kg lower than RE) levels. A significant interaction (P < 0.05) showed that HS increased glandular stomach weight and the jejunal villus length to crypt depth ratio (VCR) in LE diets, but decreased these parameters in RE diets. Dietary energy reduction impaired energy metabolism in the ileum (P < 0.05) mainly via decreasing the gene expression of enzymes involved in the tricarboxylic acid (TCA) cycle (α-ketoglutarate dehydrogenase complex [α-KGDH]; isocitrate dehydrogenase (NAD (+) [IDH] catalytic; citrate synthase [CS]) and adenosine triphosphate (ATP) synthesis, reducing contents of phosphoenolpyruvate (PEP) and adenylate energy charges (AEC) and down-regulating the adenosine monophosphate-activated protein kinase (AMPK) pathway. HS stimulated AMPKα phosphorylation, increased protein abundance of peroxisome proliferator activated-receptor gamma coactivator 1α (PGC1α) and improved contents of amino acids (aspartate, glutamate, glutamine, alanine and threonine) and malate in the ileum regardless of energy levels (P < 0.05). By an interaction (P < 0.05), the transition from LS to HS diets up-regulated ileal gene expression of AMPKα1 and decreased content of adenosine monophosphate (AMP), accompanied by higher AEC but only in birds fed with LE diets. Collectively, these results suggest that low energy feeding may not be enough for maintaining intestinal energy homeostasis in layer pullets and emphasizes the importance of a relatively high starch:fat ratio in restoring energy metabolism in the ileum.

The current study aims to investigate the potential interaction between glycosylation profiles of the Ningxiang breed (NX) and Western Duroc × Landrace × Yorkshire breed (DLY) weaned piglets, and their characteristic microbes, employing integrated analyses of transcriptomics and metagenomics. Twenty-four (12 NX and 12 DLY) at 28 days of age were transported into an experimental house and fed the same weaned piglet diet. The trail period was 7 days. Results revealed that the NX piglets had a higher growth-to-feed ratio, body weight gain scale, and lower pathological score of intestinal injury compared with the DLY piglets (P < 0.01). DLY piglets displayed elevated mRNA expression levels of MUC2 and MUC5AC in colonic mucosal tissue than NX piglets (P < 0.05). Within the O-linked glycosylated differentially expressed genes (DEGs), FNTA, GALNT18, POMGNT1, POMGNT2, and POMT1 were significantly upregulated in DLY piglets relative to NX piglets (P < 0.05). Conversely, C1GALT2, GALNT1, KMT2C, and OGT were significantly downregulated in DLY piglets compared to NX piglets (P < 0.05). The KMT2C gene was hardly expressed in the transcriptome of DLY piglets. At the phylum taxonomic level, NX piglets had a higher abundance of Firmicutes, while DLY piglets had a higher abundance of Proteobacteria. At the genus taxonomic level, NX piglets had a higher abundance of Lactobacillus, whereas DLY piglets had a higher abundance of Collinsella, Enterococcus and Escherichia. The results of the correlation between intestinal differential bacteria and O-chain glycosylated DEG showed that C1GALT2, GALNT1 and KMT2 were associated with Lactobacillus_pontis showed a positive correlation (R = 0.67). Through comparative analysis of differentially glycosylated genes and their associated functions, this study highlights the potential role of reduced expression of GALNT1 and KMT2C genes, involved in O-linked protein and glycan reactions, in impairing the intestinal barrier function of DLY piglets. Furthermore, members of the Lactobacillus and Prevotella genera may actively contribute to the regulation of piglet colon glycosylation profiles.

Growth retardation affects the health and production of livestock, while overexertion can cause sudden cardiac arrest. Both cases are considered to be metabolic disorders and are detrimental to livestock production. Effective measures for relieving or treating these disorders are scarce. However, Pimpinella thellungiana H. Wolff (P. thellungiana), a medicinal herb, has been reported to relieve growth retardation and overexertion in ethnopharmacological clinical trials. This paper summarizes and classifies a total of 106 bioactive compounds that were isolated and identified from P. thellungiana, including flavonoids, simple phenylpropanoids, coumarins, volatile compounds, and simple polyphenols, and discusses its pharmaceutical benefits, including its growth-promoting, antioxidant, anti-inflammatory, anti-atherosclerotic, and hepatoprotective properties. The nutrition, metabolism, biological activities, and pharmacological effects of the principal compounds of P. thellungiana in livestock are reviewed, as well as their potential molecular targets and metabolic signaling pathways in which these compounds are involved. However, the pharmacological and toxicological effects of some compounds have not been well documented, and further investigations of the bioactive compounds are needed. Such studies are crucial for the development of natural drugs or feed additives from P. thellungiana to alleviate growth retardation and mitigate injuries from overexertion in livestock.