Effect of dietary α-ketoglutarate and allicin supplementation on the composition and diversity of the cecal microbial community in growing pigs

Allicin in pregnancy diets modulates steroid metabolism in pregnant sows and placental sulphate metabolism promoting placental angiogenesis and foetal development

The low-birth-weight of piglets is an important factor affecting pig enterprises. The placenta, as a key organ for material exchange between mother and foetus, directly influences the growth and development of the foetus. Allicin exhibits various biological activities, including anti-inflammatory and antioxidant properties. It may also play a crucial role in enhancing sow reproductive performance and placental angiogenesis. In this study, we used 70 lactating Landrace × Yorkshire binary heterozygous sows to explore the effect of allicin on the reproductive performance of sows and placental development. The sows were randomly assigned into the Allicin group (Allicin), which was fed with a diet containing 0.25% allicin, and the negative control group, which was fed with basal feed. The experimental period lasted for 114 d from the date of mating to the end of farrowing. The results showed that the addition of allicin to the gestation diets increased the number of total born piglets, born alive piglets, and high-birth-weight piglets, reduced peripartum oxidative stress, alleviated dysregulation of glucose-lipid metabolism in sows, and increased the levels of antioxidant markers in the placenta. Differential analysis of metabolites in maternal plasma and placenta samples by non-targeted metabolomics revealed that allicin improved cholesterol metabolism, steroid biosynthesis, and increased plasma progesterone levels in sows. Allicin promoted sulphur metabolism, cysteine and methionine metabolism in placental samples and increased the hydrogen sulphide (H2S) content in the placenta. In addition, Quantitative Real-time PCR, Western blot and immunofluorescence results showed that allicin upregulated the expression of angiogenesis-related genes, VEGF-A, FLK 1 and Ang 1, in the placenta, implying that it promoted placental angiogenesis. These results indicate that supplementing the diet of pregnant sows with allicin reduces oxidative stress, alleviates dysregulation of glucose-lipid metabolism during the periparturient period, and promotes placental angiogenesis and foetal development by increasing plasma progesterone level and placental H2S content.

α-Ketoglutarate for Preventing and Managing Intestinal Epithelial Dysfunction

The epithelium lining the intestinal tract serves a multifaceted role. It plays a crucial role in nutrient absorption and immune regulation and also acts as a protective barrier, separating underlying tissues from the gut lumen content. Disruptions in the delicate balance of the gut epithelium trigger inflammatory responses, aggravate conditions such as inflammatory bowel disease, and potentially lead to more severe complications such as colorectal cancer. Maintaining intestinal epithelial homeostasis is vital for overall health, and there is growing interest in identifying nutraceuticals that can strengthen the intestinal epithelium. α-Ketoglutarate, a metabolite of the tricarboxylic acid cycle, displays a variety of bioactive effects, including functioning as an antioxidant, a necessary cofactor for epigenetic modification, and exerting anti-inflammatory effects. This article presents a comprehensive overview of studies investigating the potential of α-ketoglutarate supplementation in preventing dysfunction of the intestinal epithelium.

Altitude-dependent metabolite biomarkers reveal the mechanism of plateau pika adaptation to high altitudes

The harsh environment in the Tibetan plateau, the highest place in the world, poses thermoregulatory challenges and hypoxic stress to animals. The impacts of plateau environment on animal physiology and reproduction include external factors such as strong ultraviolet radiation and low temperature, and internal factors such as animal metabolites and gut microbiota. However, it remains unclear how plateau pika adapt to high altitudes through the combination of serum metabolites and gut microbiota. To this end, we captured 24 wild plateau pikas at the altitudes of 3400, 3600, or 3800 m a.s.l. in a Tibetan alpine grassland. Using the machine learning algorithms (random forest), we identified five biomarkers of serum metabolites indicative of the altitudes, that is, dihydrotestosterone, homo-l-arginine, alpha-ketoglutaric-acid, serotonin, and threonine, which were related to body weight, reproduction, and energy metabolism of pika. Those metabolic biomarkers were positively correlated with Lachnospiraceae_ Agathobacter, Ruminococcaceae, or Prevotellaceae_Prevotella, suggesting the close relationship between metabolites and gut microbiota. By identifying the metabolic biomarkers and gut microbiota analysis, we reveal the mechanisms of adaptation to high altitudes in plateau pika.

Castration alters the cecal microbiota and inhibits growth in Holstein cattle

To determine the effects of castration on growth performance, serum hormone levels, cecal microbiota composition, and metabolites in cattle. A total of 18 Holstein bulls and steers were divided into bull and steer groups and randomly assigned to 3 pens (3 cattle per pen, and each cattle were separated by a fence) to determine the average daily gain (ADG), daily dry matter intake (DMI), and feed efficiency (G/F). After the finishing trial, six cattle per group were randomly slaughtered. Serum was collected to measure the hormone concentration, and the cecal content was collected to measure the pH, short-chain fatty acids, and digestive enzyme activities. Metagenome sequencing and untargeted metabolomics were used to investigate the microbiota composition, functional profiles, and differential metabolites of the cecal contents. We found that castration significantly decreased ADG, DMI, and G/F in cattle (P < 0.05). The serum testosterone, thyroxine, growth hormone (P < 0.05), and triiodothyronine (P < 0.01) concentrations significantly decreased in the steer group when compared to those of the bull group. The activities of cellulase, xylanase, pectinase, and β-glucosidase (P < 0.05) significantly decreased in the steer group, whereas the activities of lipase and α-amylase significantly increased. Moreover, castration significantly decreased the relative abundance of Ruminococcaceae_bacterium, Treponema_porcinum, Oscillibacter_sp. (P < 0.05), and Alistipes_senegalensis (P < 0.01), whereas the relative abundance of Phocaeicola_plebeius (P < 0.05) was significantly increased. Also, the relative abundance of Phocaeicola_plebeius was negatively correlated with testosterone levels, and the function of the cecal microbiota was enriched in the GH29 and GH97 families in the steer group. Metabolomic analysis indicated that castration increased the levels of L-valine, L-phenylalanine, L-aspartic acid, L-isoleucine, L-lysine, methionine, L-glutamic acid, and L-leucine, while decreasing the levels of α-ketoglutaric acid through the 2-oxocarboxylic acid metabolism pathway. In addition, α-ketoglutaric acid was negatively correlated with Oscillibacter_sp. (P < 0.01). Overall, castration can inhibit cattle growth by altering the composition of the cecal microbiota. Therefore, this study provides a theoretical and practical basis for improving the growth performance of steers.

Current studies and potential future research directions on biological effects and related mechanisms of allicin

Allicin, a thiosulfonate extract from freshly minced garlic, has been reported to have various biological effects on different organs and systems of animals and human. It can reduce oxidative stress, inhibit inflammatory response, resist pathogen infection and regulate intestinal flora. In addition, dozens of studies also demonstrated allicin could reduce blood glucose level, protect cardiovascular system and nervous system, and fight against cancers. Allicin was widely used in disease prevention and health care. However, more investigations on human cohort study are needed to verify the biological or clinical effects of allicin in the future. In this review, we summarized the biological effects of allicin from previous outstanding and valuable studies and provided useful information for future studies on the health effects of allicin.

Advances in pathogenesis and therapeutic strategies for osteoporosis

Osteoporosis, is the most common bone disorder worldwide characterized by low bone mineral density, leaving affected bones vulnerable to fracture. Bone homeostasis depends on the precise balance between bone resorption by osteoclasts and bone matrix formation by mesenchymal lineage osteoblasts, and involves a series of complex and highly regulated steps. Bone homeostasis will be disrupted when the speed of bone resorption is faster than bone formation. Based on various regulatory mechanisms of bone homeostasis, a series of drugs targeting osteoporosis have emerged in clinical practice, including bisphosphonates, selective estrogen receptor modulators, calcitonin, molecular-targeted drugs and so on. However, many drugs have major adverse effects or are unsuitable for long-term use. Therefore, it is very urgent to find more effective therapeutic drugs based on the new pathogenesis of osteoporosis. In this review, we summarize novel mechanisms involved in the pathological process of osteoporosis, including the roles of gut microbiome, autophagy, iron balance and cellular senescence. Based on the above pathological mechanism, we found promising drugs for osteoporosis treatment, such as: probiotics, alpha-ketoglutarate, senolytics and hydrogen sulfide. This new finding may provide an important basis for elucidating the complex pathological mechanisms of osteoporosis and provide promising drugs for clinical osteoporosis treatment.

Gut relief formula attenuates dextran sulfate sodium-induced colitis by regulating NF-κB signaling and the intestinal microbiota in mice

Background. Inflammatory bowel disease (IBD) is a chronic relapsing disorder of the gastrointestinal tract. The nutrition care gut relief formula (GR), a combination of natural products and nutrients, has been shown to benefit gastrointestinal health. However, the underlying mechanism responsible for this effect is incompletely defined. Objective. This study was conducted to evaluate the hypothesis that GR could attenuate dextran sulfate sodium (DSS)-induced colitis by enhancing intestinal mucosal immunity and regulating intestinal microflora in mice. Methods. Six-week-old C57BL/6J mice orally administered with GR (7.5 mg per mouse per day) or an equal volume of vehicle were treated with sterile water or 2.5% DSS for 6 days to induce colitis. Histological damage, inflammatory cell infiltration, and colonic microbiome community were analyzed to evaluate the beneficial effect of GR. Results. GR administration ameliorated the severity of colitis as evidenced by reduced body weight loss, decreased colon shortening, reduced myeloperoxidase (MPO) activity, inhibited proinflammatory cytokine secretion, and decreased histological damage in DSS-challenged mice. Additionally, enhancement of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) in response to DSS was attenuated by GR administration. Meanwhile, DSS treatment resulted in reduction of the glutathione (GSH) level and tight junction protein abundance, as compared with the controls. Of note, these adverse effects were remarkably eliminated by GR administration. Further study showed that the protective effect of GR was associated with the inhibited activation of STAT3 and NF-κB signaling pathways, as well as upregulated abundances of Lactobacillus in the colon tissues of mice. Conclusion. Collectively, the data provided herein demonstrated that GR administration alleviated intestinal mucosal inflammation and mucosal barrier dysfunction. These beneficial effects were associated with inhibited activation of STAT3 and NF-κB signaling pathways, as well as upregulated abundances of Lactobacillus in the colon tissues of mice.

The nutritional applications of garlic (Allium sativum) as natural feed additives in animals

Garlic (Allium sativum) is an essential vegetable that has been widely utilized as seasoning, flavoring, culinary and in herbal remedies. Garlic contains several characteristic organosulfur compounds, such as diallyl sulfide, allicin (diallyl thiosulphate), γ-glutamylcysteine, and S-allyl cysteine (alliin) and ajoene, which garlic has beneficial effects on inflammation, oxidative stress markers, hypertension, hyperlipidaemia and endothelial function in vitro or in animal model. These bioactive molecules are also playing pivotal role in livestock and fisheries production apart from its application in humans. Supplementation of animal feed with garlic and its related products is consistent with the modern agricultural concept of organic animal husbandry. This review compiles the information describing the effects of feeding garlic and its extracts on selected performance parameters in animals (chicken, rabbits, ruminants, pigs and fish). This review may provide reference for scientists and entrepreneurs to investigate the applications of feeds added with garlic and allicin by-products for the improvement of animal husbandry and aquatic production.

Dietary Supplementation of Inorganic, Organic, and Fatty Acids in Pig: A Review

Simple Summary

The role of acids in pig feed strategies has changed from feed acidifier and preservative to growth promoter and antibiotics substitute. Since the 2006 European banning of growth promoters in the livestock sector, several feed additives have been tested with the goal of identifying molecules with the greatest beneficial antimicrobial, growth-enhancing, or disease-preventing abilities. These properties have been identified among various acids, ranging from inexpensive inorganic acids to organic and fatty acids, and these have been widely used in pig production. Acids are mainly used during the weaning period, which is considered one of the most critical phases in pig farming, as well as during gestation, lactation, and fattening. Such supplementation generally yields improved growth performance and increased feed efficiency; these effects are the consequences of different modes of action acting on the microbiome composition, gut mucosa morphology, enzyme activity, and animal energy metabolism.

Abstract

Reduction of antibiotic use has been a hot topic of research over the past decades. The European ban on growth-promoter use has increased the use of feed additivities that can enhance animal growth performance and health status, particularly during critical and stressful phases of life. Pig farming is characterized by several stressful periods, such as the weaning phase, and studies have suggested that the proper use of feed additives during stress could prevent disease and enhance performance through modulation of the gastrointestinal tract mucosa and microbiome. The types of feed additive include acids, minerals, prebiotics, probiotics, yeast, nucleotides, and phytoproducts. This review focuses on commonly used acids, classified as inorganic, organic, and fatty acids, and their beneficial and potential effects, which are widely reported in the bibliography. Acids have long been used as feed acidifiers and preservatives, and were more recently introduced into feed formulated for young pigs with the goal of stabilizing the stomach pH to offset their reduced digestive capacity. In addition, some organic acids represent intermediary products of the tricarboxylic acid cycle (TCA), and thus could be considered an energy source. Moreover, antimicrobial properties have been exploited to modulate microbiota populations and reduce pathogenic bacteria. Given these potential benefits, organic acids are no longer seen as simple acidifiers, but rather as growth promoters and potential antibiotic substitutes owing to their beneficial action on the gastrointestinal tract (GIT).

Baicalin-Copper Complex Modulates Gut Microbiota, Inflammatory Responses, and Hormone Secretion in DON-Challenged Piglets

Simple Summary

Deoxynivalenol (DON) is the most common mycotoxin contaminant in the agriculture industry worldwide. Copper is very efficacious in promoting growth performance and improving feed remuneration, and baicalin may alleviate oxidative stress and inflammatory responses in humans and animals. We speculated that the combined effect of baicalin and copper would have some effect in DON-challenged piglets. The present study examined the effects of a baicalin-copper complex on inflammatory responses, hormone secretion, and gut microbiota in DON challenged piglets. These findings provide new application prospects in piglets involving the combination of baicalin and copper.

Abstract

The present experiment assessed the inflammatory responses, hormone secretion, and gut microbiota of weanling piglets administered baicalin-copper complex (BCU) or deoxynivalenol (DON) supplementation diets. Twenty-eight piglets were randomly assigned to four groups: control diet (Con group), a 4 mg DON/kg diet (DON group), a 5 g BCU/kg diet (BCU group), a 5 g BCU + 4 mg DON/kg diet (DBCU group). After 14 days, the results showed that dietary BCU supplementation remarkably increased the relative abundance of Clostrium bornimense and decreased the relative abundance of Lactobacillus in the DBCU group (p < 0.05). BCU decreased the serum concentration of IgG, IL-2, IFN-γ, and IgA in DON treated piglets (p < 0.05), and promoted the serum concentration of IL-1β, IgG, IL-2, IFN-γ, IgA, IL-6, IgM, and TNFα in normal piglets (p < 0.05). BCU increased the concentrations of serum IGF1, insulin, NPY, GLP-1, and GH, and decreased the concentrations of serum somatostatin in no DON treated piglets (p < 0.05). Dietary BCU supplementation significantly promoted the secretion of somatostatin, and inhibited the secretion of leptin in piglets challenged with DON (p < 0.05). BCU regulated the expression of food intake-related genes in the hypothalamus and pituitary of piglets. Collectively, dietary BCU supplementation alleviated inflammatory responses and regulated the secretion of appetite-regulating hormones and growth-axis hormones in DON challenged piglets, which was closely linked to changes of intestinal microbes.

Allicin-induced host-gut microbe interactions improves energy homeostasis

Allicin (diallylthiosulfinate) is a natural food compound with multiple biological and pharmacological functions. However, the mechanism of beneficial role of Allicin on energy homeostasis is not well studied. Gut microbiota (GM) profoundly affects host metabolism via microbiota-host interactions and coevolution. Here, we investigated the interventions of beneficial microbiome induced by Allicin on energy homeostasis, particularly obesity, and related complications. Interestingly, Allicin treatment significantly improved GM composition and induced the most significant alteration enrichment of Bifidobacterium and Lactobacillus. Importantly, transplantation of the Allicin-induced GM to HFD mice (AGMT) played a remarkable role in decreasing adiposity, maintaining glucose homeostasis, and ameliorating hepatic steatosis. Furthermore, AGMT was effective in modulating lipid metabolism, activated brown adipose tissues (BATs), induced browning in sWAT, reduced inflammation, and inhibited the degradation of intestinal villi. Mechanically, AGMT significantly increased Blautia [short-chain fatty acids (SCFAs)-producing microbiota] and Bifidobacterium in HFD mice, also increased the SCFAs in the cecum, which has been proved many beneficial effects on energy homeostasis. Our study highlights that Allicin-induced host-gut microbe interactions plays an important role in regulating energy homeostasis, which provides a promising potential therapy for obesity and metabolic disorders based on host-microbe interactions.

Gut microbiome: A possible common therapeutic target for treatment of atherosclerosis and cancer

Human gut microbiota is a dynamic and variable system that can change over time and in response to different diets and treatments. There is currently no doubt that gut microbiota can provide interesting therapeutic opportunities, since it can metabolize biologically active molecules, drugs, and their precursors, and control their bioavailability. Moreover, it can produce both beneficial and dangerous metabolites that influence host's health. In this review, we summarize the current knowledge on the involvement of gut microbiota in two chronic human pathologies that represent the greatest challenges of modern medicine: atherosclerosis and cancer. Interesting parallels are observed between the mechanisms and possible treatment approaches of these pathologies. Some of the common effects of therapeutic agents targeting both pathologies, such as anti-inflammatory activity, are partially mediated by the gut microbiota. We will discuss the effects of common drugs (metformin, statins and aspirin) and various nutraceuticals on gut microbiota and outline the pathways of microbial involvement in mediating the pleiotropic beneficial effects of these agents in atherosclerosis and cancer.

Effects of ornithine α-ketoglutarate on growth performance and gut microbiota in a chronic oxidative stress pig model induced by d-galactose

d-Galactose induced chronic oxidative stress and also proved the positive effects of 0.5% ornithine α-ketoglutarate on altering the pig gut microbe, restoring serum amino acid and alleviating the growth-suppression induced by d-galactose chronic oxidative stress.

BOARD INVITED REVIEW: The pig microbiota and the potential for harnessing the power of the microbiome to improve growth and health1

A variety of microorganisms inhabit the gastrointestinal tract of animals including bacteria, archaea, fungi, protozoa, and viruses. Pioneers in gut microbiology have stressed the critical importance of diet:microbe interactions and how these interactions may contribute to health status. As scientists have overcome the limitations of culture-based microbiology, the importance of these interactions has become more clear even to the extent that the gut microbiota has emerged as an important immunologic and metabolic organ. Recent advances in metagenomics and metabolomics have helped scientists to demonstrate that interactions among the diet, the gut microbiota, and the host to have profound effects on animal health and disease. However, although scientists have now accumulated a great deal of data with respect to what organisms comprise the gastrointestinal landscape, there is a need to look more closely at causative effects of the microbiome. The objective of this review is intended to provide: 1) a review of what is currently known with respect to the dynamics of microbial colonization of the porcine gastrointestinal tract; 2) a review of the impact of nutrient:microbe effects on growth and health; 3) examples of the therapeutic potential of prebiotics, probiotics, and synbiotics; and 4) a discussion about what the future holds with respect to microbiome research opportunities and challenges. Taken together, by considering what is currently known in the four aforementioned areas, our overarching goal is to set the stage for narrowing the path towards discovering how the porcine gut microbiota (individually and collectively) may affect specific host phenotypes.

Dietary supplementation with the extract from Eucommia ulmoides leaves changed epithelial restitution and gut microbial community and composition of weanling piglets

This study was conducted to compare the effects of Eucommia ulmoides leaves (EL) in different forms (EL extract, fermented EL, and EL powder) with antibiotics on growth performance, intestinal morphology, and the microbiota composition and diversity of weanling piglets. Compared to the control group, the antibiotics and EL extract significantly increased the average daily gain and decreased the feed: gain ratio as well as the diarrhea rate (P < 0.05). The EL extract significantly decreased the crypt depth and increased the ratio of villus height to crypt depth (P < 0.05), while the fermented EL group did the opposite (P < 0.05). The crypt depth in the antibiotics group was of similar value to the EL extract group, and was lower than the fermented EL and EL powder groups (P < 0.05). Compared to the control and antibiotics groups, the jejunul claudin-3 mRNA expression and the concentrations of total VFA, Chao 1, and ACE were significantly augmented in the EL extract group of piglets (P < 0.05). The EL extract groups also showed elevated Shannon (P < 0.05) and Simpson (P = 0.07) values relative to the control and antibiotics groups. At the phylum level, the EL extract group exhibited a reduced abundance of Bacteroidetes and an enhanced abundance of Firmicutes. At the genus level, the abundance of Prevotella was augmented in the EL extract group. Moreover, compared with the antibiotic group, the acetate concentration was enhanced in the EL extract and fermented EL groups. Overall, dietary supplementation with the EL extract, but not the fermented EL or EL powder, improved growth performance, jejunul morphology and function, as well as changed colonic microbial composition and diversity, which might be an alternative to confer protection against weanling stress in weanling piglets.

Effects of kojic acid on boar sperm quality and anti-bacterial activity during liquid preservation at 17 C

Bacteriospermia is a documented risk to sperm quality when boar semen is stored at 17 °C. The objective of this study was to evaluate the effects of kojic acid (KA) on sperm quality and anti-bacterial effect during liquid storage boar semen at 17 °C, as well as to explore sperm-oocyte binding and embryonic development in vitro. Boar semen was diluted with Beltsville thawing solution (BTS), and it contained KA at different concentrations (0, 0.02, 0.04, 0.06, 0.08, and 0.10 g/L). Bacterial concentrations and sperm quality parameters (motility, mitochondrial membrane potential, acrosome integrity, and plasma membrane integrity) were evaluated on each experimental day. Differences in microbial compositions were compared using 16S rDNA sequencing among the control group, 0.04 g/L KA, and 0.25 g/L gentamycin groups on experimental day 5, and the effects of KA on sperm capacitation, Western blot, total anti-oxidant capacity (T-AOC), reactive oxygen species (ROS) content, malondialdehyde (MDA) content, in vitro fertilization (IVF) parameters, sperm-oocyte binding, cleavage rates, and blastocyst rates were evaluated. The results showed that KA at the optimum concentration of 0.04 g/L significantly improved sperm quality parameters and sperm capacitation, increased T-AOC ability, enhanced IVF parameters and sperm-oocyte binding, increased cleavage and blastocyst rates, inhibited bacterial concentrations, reduced ROS and MDA content, and altered bacterial compositions (P < 0.05). Moreover, KA also increased the expression of anti-oxidant-related proteins, SOD1, SOD2 and CAT, and anti-apoptosis-related protein, Bcl 2, and decreased the expression of apoptosis-related proteins, caspase 3 and Bax in sperm (P < 0.05). These findings demonstrated that supplementation of antibiotic-free extenders for boar semen with 0.04 g/L KA has beneficial effects on liquid boar sperm preservation.

Intervention with α-Ketoglutarate Ameliorates Colitis-Related Colorectal Carcinoma via Modulation of the Gut Microbiome

The intestinal microbiome plays a crucial role in promoting intestinal health, and perturbations to its constitution may result in chronic intestinal inflammation and lead to colorectal cancer (CRC). α-Ketoglutarate is an important intermediary in the NF-κB-mediated inflammatory pathway that maintains intestinal homeostasis and prevents initiation of intestinal inflammation, a known precursor to carcinoma development. The objective of this study was to assess the potential protective effects of α-ketoglutarate intervention against CRC development, which may arise due to its known anti-inflammatory and antitumour effects. CRC was induced in C57BL/6 mice using azoxymethane (AOM) and dextran sulfate sodium (DSS). Tumour frequency, histological rating, and colonic microbiota were assessed in colonic samples. The findings demonstrated that α-ketoglutarate offered significant protection against CRC development in mice. Furthermore, α-ketoglutarate also exhibited immunomodulatory effects mediated via downregulation of interleukin (IL)-6, IL-22, tumour necrosis factor (TNF)-α, and IL-1β cytokines. Finally, intervention with α-ketoglutarate tended to minimise the frequency of opportunistic pathogens (Escherichia and Enterococcus) while increasing the populations of Akkermansia, Butyricicoccus, Clostridium, and Ruminococcus. Taken together, our findings show that dietary α-ketoglutarate intervention may protect against inflammation-related CRC.