Modulation of Gut Microbiota and Oxidative Status by β-Carotene in Late Pregnant Sows

Oat protein isolate-Pleurotus ostreatus β-glucan conjugate nanoparticles bound to β-carotene effectively alleviate immunosuppression by regulating gut microbiota

Individuals with immune disorders cannot establish an adequate defense to pathogens, leading to gut microbiota dysbiosis. β-Carotene can regulate immune response, but its bioavailability in vivo is very low. Herein, we developed a glycosylated oat protein-based nanoparticle to improve the application of β-carotene for mitigating cyclophosphamide-induced immunosuppression and gut microbiota imbalance in mice. The results showed that the nanoparticles facilitated a conversion of β-carotene to retinol or retinyl palmitate into the systemic circulation, leading to an increased bioavailability of β-carotene. The encapsulated β-carotene bolstered humoral immunity by elevating immunoglobulin levels, augmenting splenic T lymphocyte subpopulations, and increasing splenic cytokine concentrations in immunosuppressed mice. This effect was accompanied by the alleviation of pathological features observed in the spleen. In addition, the encapsulated β-carotene restored the abnormal gut microbiota associated with immunosuppression, including Erysipelotrichaceae, Akkermansia, Bifidobacterium and Roseburia. This study suggested that nanoparticles loaded with β-carotene have great potential for therapeutic intervention in human immune disorders by specifically targeting the gut microbiota.

Polysaccharides affect the utilization of β-carotene through gut microbiota investigated by in vitro and in vivo experiments

This study aimed to evaluate the effects of six polysaccharides on the utilization of β-carotene from the perspective of gut microbiota using both in vitro simulated anaerobic fermentation systems and in vivo animal experiments. In the in vitro experiments, the addition of arabinoxylan, arabinogalactan, mannan, inulin, chitosan, and glucan led to a 31.07-79.12% decrease in β-carotene retention and a significant increase in retinol content (0.21-0.99-fold) compared to β-carotene alone. Among them, the addition of chitosan produced the highest level of retinol. In the in vivo experiments, mice treated with the six polysaccharides exhibited a significant increase (2.51-5.78-fold) in serum β-carotene content compared to the group treated with β-carotene alone. The accumulation of retinoids in the serum, liver, and small intestine increased by 13.56-21.61%, 12.64-56.27%, and 7.9%-71.69%, respectively. The expression of β-carotene cleavage enzymes was increased in the liver. Genetic analysis of small intestinal tissue revealed no significant enhancement in the expression of genes related to β-carotene metabolism. In the gut microbiota environment, the addition of polysaccharides generated more SCFAs and altered the structure and composition of the gut microbiota. The correlation analysis revealed a strong association between gut microbes (Ruminococcaceae and Odoribacteraceae) and β-carotene metabolism and absorption. Collectively, our findings suggest that the addition of polysaccharides may improve β-carotene utilization by modulating the gut microbiota.

Effects of main active components of rosemary on growth performance, meat quality and lipid metabolism in finishing pigs

Rosemary extracts have been widely used as feed additives in recent years. This study aimed to investigate the effects of rosmarinic acid (RA) and ursolic acid (UA), the main active components of rosemary, on growth performance, meat quality and lipid metabolism in finishing pigs. A total of 72 finishing pigs (Landrace; initial age of 150 d) were randomly divided into 3 treatments with 8 replicates of 3 pigs each, and fed a basal diet or diet containing 500 mg/kg of RA or UA. The results showed that dietary supplementation of RA or UA had no significant effect on the growth performance and carcass traits of finishing pigs (P > 0.05). However, both RA and UA significantly increased the triglyceride (TG) level in soleus muscle (P < 0.001). Supplementation of RA increased the expression of genes related to lipogenesis and transport including fatty acid synthase (FAS) (P < 0.001), sterol regulatory element binding protein-1c (SREBP1c) (P < 0.001) and peroxisome proliferator-activated receptor γ (PPARγ) (P < 0.05), while UA increased the expression of fatty acid transport protein 1 (FATP1), a gene related to lipid uptake (P < 0.05). However, RA reduced the expression of adipogenesis-related gene acetyl-coenzyme A carboxylase α (ACCα) (P < 0.01). Characterization of cecal microbiota indicated that RA increased the microbial richness (chao 1, P < 0.001) and diversity (observed species, P < 0.01). Further analysis of the genera revealed that RA increased the relative abundance of Bacteroides and g-UCG-005 (P < 0.05), and UA enriched Prevotella (P < 0.001). Correlation analysis showed that g-UCG-005 was positively correlated with the expression of FAS, carnitine palmitoyl transferase 1B (CPT1B), SREBP1c and PPARγ (P < 0.01). In conclusion, dietary supplementation of RA or UA may increase fat deposition in muscle of finishing pigs by regulating lipid metabolism and gut microbiota.

The Dose-Response Effect of Fluoride Exposure on the Gut Microbiome and Its Functional Pathways in Rats

Metabolic activities within the gut microbiome are intimately linked to human health and disease, especially within the context of environmental exposure and its potential ramifications. Perturbations within this microbiome, termed "gut microbiome perturbations", have emerged as plausible intermediaries in the onset or exacerbation of diseases following environmental chemical exposures, with fluoride being a compound of particular concern. Despite the well-documented adverse impacts of excessive fluoride on various human physiological systems-ranging from skeletal to neurological-the nuanced dynamics between fluoride exposure, the gut microbiome, and the resulting dose-response relationship remains a scientific enigma. Leveraging the precision of 16S rRNA high-throughput sequencing, this study meticulously examines the ramifications of diverse fluoride concentrations on the gut microbiome's composition and functional capabilities within Wistar rats. Our findings indicate a profound shift in the intestinal microbial composition following fluoride exposure, marked by a dose-dependent modulation in the abundance of key genera, including Pelagibacterium, Bilophila, Turicibacter, and Roseburia. Moreover, discernible alterations were observed in critical functional and metabolic pathways of the microbiome, such as D-lyxose ketol-isomerase and DNA polymerase III subunit gamma/tau, underscoring the broad-reaching implications of fluoride exposure. Intriguingly, correlation analyses elucidated strong associations between specific bacterial co-abundance groups (CAGs) and these shifted metabolic pathways. In essence, fluoride exposure not only perturbs the compositional equilibrium of the gut microbiota but also instigates profound shifts in its metabolic landscape. These intricate alterations may provide a mechanistic foundation for understanding fluoride's potential toxicological effects mediated via gut microbiome modulation.

Deposition and bioconversion law of β-carotene in laying hens after long-term supplementation under adequate vitamin A status in the diet

β-Carotene, because it is the precursor of vitamin A and has versatile biological roles, has been applied as a feed additive in the poultry industry for a long time. In this study, we investigated the deposition and bioconversion of β-carotene in laying hens. A total of 600 Hy-line brown laying hens at 40 wk of age were randomly divided into 5 dietary treatments, each group's dietary supplemental levels of β-carotene were 0, 15, 30, 60, 120 mg/kg feed, and the vitamin A levels were all 8,000 IU/kg. After 14-wk trial, samples were collected, then carotenoids and different forms of vitamin A were detected using the novel method developed by our laboratory. We found that dietary β-carotene treatment had no significant effects on laying hens' production performance and egg quality (P > 0.05), except the yolk color. The deposition of β-carotene in the body gradually increased (P < 0.01) with the supplemental dose, whereas the contents of lutein and zeaxanthin decreased (P < 0.05). When the β-carotene supplemental level was above 30 mg/kg in the diet, the different forms of vitamin A in in serum, liver, ovary, and yolks were increased compared to the control group (P < 0.05). However, these indicators decreased when the additional dose was 120 mg/kg. Moreover, the mRNA levels of the genes involved in β-carotene absorption, bioconversion, and negative feedback regulation in duodenal mucosa and liver were upregulated after long-term feeding (P < 0.05). Histological staining of the ovaries indicated that the deposition of β-carotene led to a lower rate of follicle atresia (P < 0.05), and this positive effects may be related to the antioxidant function of β-carotene, which caused a reduction of oxidation products in the ovary (P < 0.05). Altogether, β-carotene could accumulate in laying hens intactly and exert its biological functions in tissue. Meanwhile, a part of β-carotene could also be converted into vitamin A but this bioconversion has an upper limit and negative feedback regulation.

Dietary carotenoids to improve hypertension

Hypertension is one of the major risk factors for cardiovascular diseases and the main reason for premature death in older adults. Although antihypertensive medications have been used frequently, hypertension prevalence has increased in the last decade. Lifestyle improvement is a cornerstone of hypertension prevention and control. High dietary consumptions of fruits and vegetables are linked to reduced risks of high blood pressure. Carotenoids are natural tetraterpene pigments produced by bacteria, fungi, algae, some animals, and various plants. Because of their high pharmacological potential and safety, they have been mentioned as unique therapeutic agents for a diverse range of diseases. Carotenoids modulate high blood pressure. They also have several additional benefits for the cardiovascular system, including antioxidative, anti-inflammatory, anti-atherogenic, and antiplatelet effects. They improve endothelial function and metabolic profile, as well. In the present article, we reviewed the literature data regarding carotenoids' influence on hypertension in both preclinical and clinical studies. Furthermore, we reviewed the underlying mechanisms associated with antihypertensive properties derived from in vitro and in vivo studies. Suppressing reactive oxygen species (ROS) production, Inhibiting angiotensin-II, endothelin-1, and oxidized low-density lipoprotein; and also nitric oxide enhancement are some of the mechanisms by which they lower blood pressure. The present article indicated that astaxanthine, β-carotene, bixin, capsanthin, lutein, crocin, and lycopene have antihypertensive properties. Having significant antioxidant properties, they can decrease high blood pressure and concomitant comorbidities.

Effect of carotenoids on gut health and inflammatory status: A systematic review of in vivo animal studies

Carotenoids have anti-inflammatory and antioxidant properties, being a potential bioactive compound for gut health. The objective of this systematic review was to investigate the effects of carotenoids on gut microbiota, gut barrier, and inflammation in healthy animals. The systematic search from PubMed, Scopus, and Lilacs databases were performed up to March 2023. The final screening included thirty studies, with different animal models (mice, rats, pigs, chicks, drosophila, fish, and shrimp), and different carotenoid sources (β-carotene, lycopene, astaxanthin, zeaxanthin, lutein, and fucoxanthin). The results suggested that carotenoids seem to act on gut microbiota by promoting beneficial effects on intestinal bacteria related to both inflammation and SCFA production; increase tight junction proteins expression, important for reducing intestinal permeability; increase the mucins expression, important in protecting against pathogens and toxins; improve morphological parameters important for digestion and absorption of nutrients; and reduce pro-inflammatory and increase anti-inflammatory cytokines. However, different carotenoids had distinct effects on gut health. In addition, there was heterogeneity between studies regarding animal model, duration of intervention, and doses used. This is the first systematic review to address the effects of carotenoids on gut health. Further studies are needed to better understand the effects of carotenoids on gut health.

Regulation of gut microbiota by vitamin C, vitamin E and β-carotene

Vitamin C (VC), vitamin E (VE) and β-carotene (βC) are representative dietary antioxidants, which exist in daily diet and can increase the antioxidant capacity of body fluids, cells and tissues. The health benefits of vitamins like VC, VE and βC are widely demonstrated. Given that the strong associations between the gut microbiota and host health or a range of diseases has been extensively reported, it is important to explore the modulatory effects of known vitamins on the gut microbiota. Herein, this article reviews the effects of VC, VE and βC on the gut microbiota. Totally, 19 studies were included, of which eight were related to VC, nine to VE, and six to βC. Overall, VC, VE and βC can provide health benefits to the host by modulating the composition and metabolic activity of the gut microbiota, improving intestinal barrier function and maintaining the normal function of the immune system. Two perspectives are proposed for future studies: i) roles of known antioxidant activity of vitamins in regulating the gut microbiota and its molecular mechanism need to be further studied; ii) causal relationships between the regulatory effects of vitamins on gut microbiota and host health still remains to be further verified.

Diversity and structural analysis of rhizosphere soil microbial communities in wild and cultivated Rhizoma Atractylodis Macrocephalae and their effects on the accumulation of active components

Rhizosphere microorganisms are the main factors affecting the formation of high quality medicinal materials and promoting the accumulation of secondary metabolites. However, the composition, diversity, and function of rhizosphere microbial communities in endangered wild and cultivated Rhizoma Atractylodis Macrocephalae (RAM) and their relationships with active component accumulation have remained unclear. In this study, high-throughput sequencing and correlation analysis were used to study the rhizosphere microbial community diversity (bacteria and fungi) of three RAM species and its correlation with the accumulation of polysaccharides, atractylone, and lactones (I, II, and III). A total of 24 phyla, 46 classes, and 110 genera were detected. The dominant taxa were Proteobacteria, Ascomycota, and Basidiomycota. The microbial communities in both wild and artificially cultivated soil samples were extremely species-rich, but there were some differences in their structure and the relative abundances of microorganism taxa. Meanwhile, the contents of effective components in wild RAM were significantly higher than those in cultivated RAM. Correlation analysis showed that 16 bacterial and 10 fungal genera were positively or negatively correlated with active ingredient accumulation. These results showed that rhizosphere microorganisms could play an important role in component accumulation and might lay a foundation for future research on endangered materials.

Dietary fiber supplementation during the last 50 days of gestation improves the farrowing performance of gilts by modulating insulin sensitivity, gut microbiota, and placental function

Our previous study found dietary konjac flour (KF) supplementation could improve insulin sensitivity and reproductive performance of sows, but its high price limits its application in actual production. This study aimed to investigate the effects of supplementation of a cheaper combined dietary fiber (CDF, using bamboo shoots fiber and alginate fiber to partially replace KF) from the last 50 days of gestation to parturition on farrowing performance, insulin sensitivity, gut microbiota, and placental function of gilts. Specifically, a total of 135 pregnant gilts with a similar farrowing time were blocked by backfat thickness and body weight on day 65 of gestation (G65d) and assigned to 1 of the 3 dietary treatment groups (n = 45 per group): basal diet (CON), basal diet supplemented with 2% KF or 2% CDF (CDF containing 15% KF, 60% bamboo shoots fiber, and 25% alginate fiber), respectively. The litter performance, insulin sensitivity and glucose tolerance parameters, placental vessel density, and short-chain fatty acids (SCFAs) levels in feces were assessed. The gut microbiota population in gilts during gestation was also assessed by 16S rDNA gene sequencing. Compared with CON, both KF and CDF treatments not only increased the piglet birth weight (P < 0.05) and piglet vitality (P < 0.01) but also decreased the proportion of piglets with birth weight ≤ 1.2 kg (P < 0.01) and increased the proportion of piglets with birth weight ≥ 1.5 kg (P < 0.01). In addition, KF or CDF supplementation reduced fasting blood insulin level (P < 0.05), homeostasis model assessment-insulin resistance (P < 0.05), serum hemoglobin A1c (P < 0.05), and the level of advanced glycation end products (P < 0.05) at G110d, and increased the placental vascular density (P < 0.05) at farrowing. Meanwhile, KF or CDF supplementation increased microbial diversity (P < 0.05) and SCFAs levels (P < 0.05) in feces at G110d. Notably, the production cost per live-born piglet was lower in CDF group (¥ 36.1) than KF group (¥ 41.3). Overall, KF or CDF supplementation from G65d to farrowing could improve the farrowing performance of gilts possibly by improving insulin sensitivity, regulating gut microbiota and metabolites, and increasing placental vascular density, with higher economic benefits and a similar effect for CDF vs. KF, suggesting the potential of CDF as a cheaper alternative to KF in actual production.

Carotenoids in female and male reproduction

Carotenoids are among the best-known pigments in nature, confer color to plants and animals, and are mainly derived from photosynthetic bacteria, fungi, algae, plants. Mammals cannot synthesize carotenoids. Carotenoids' source is only alimentary and after their assumption, they are mainly converted in retinal, retinol and retinoic acid, collectively known also as pro-vitamins and vitamin A, which play an essential role in tissue growth and regulate different aspects of the reproductive functions. However, their mechanisms of action and potential therapeutic effects are still unclear. This review aims to clarify the role of carotenoids in the male and female reproductive functions in species of veterinary interest. In female, carotenoids and their derivatives regulate not only folliculogenesis and oogenesis but also steroidogenesis. Moreover, they improve fertility by decreasing the risk of embryonic mortality. In male, retinol and retinoic acids activate molecular pathways related to spermatogenesis. Deficiencies of these vitamins have been correlated with degeneration of testis parenchyma with consequent absence of the mature sperm. Carotenoids have also been considered anti-antioxidants as they ameliorate the effect of free radicals. The mechanisms of action seem to be exerted by activating Kit and Stra8 pathways in both female and male. In conclusion, carotenoids have potentially beneficial effects for ameliorating ovarian and testes function.

Effect of dietary resveratrol on placental function and reproductive performance of late pregnancy sows

Placental function is vital to the fetal growth of sows, and resveratrol (RES) can protect cells against oxidative stress, which is one of the major factors impairing placental function. This study aimed to investigate the effect of dietary resveratrol (RES) on placental function and reproductive performance during late pregnancy in a sow model from the aspects of oxidative stress, insulin resistance, and gut microbiota. A total of 26 hybrid pregnant sows (Landrace × Yorkshire) with similar parity were randomly allocated into two groups (n = 13) and fed with a basal diet or a diet containing 200 mg/kg of resveratrol from day 85 of gestation until parturition. The dietary supplementation of RES increased the litter weight at parturition by 12.53% (p = 0.145), with ameliorated insulin resistance (HOMA-IR), increased triglyceride (TG) levels, and decreased interleukin (IL)-1β and IL-6 levels in serum (p &lt; 0.05). Moreover, resveratrol increased the placental vascular density (p &lt; 0.05) with the enhanced expression of nutrient transporter genes (SLC2A1 and SLC2A3) and antioxidant genes, such as superoxide dismutase 2 (SOD2) and heme oxygenase-1 (HO-1) but declined the expression of inflammatory genes, such as IL-1β and IL-6 (p &lt; 0.05). The characterization of the fecal microbiota revealed that resveratrol decreased the relative abundance of the Christensensllaceae R-7 group and Ruminococcaceae UCG-008 (p &lt; 0.05), which had a positive linear correlation with the expression of IL-1β and IL-6 (p &lt; 0.05), but had a negative linear correlation with the expression of SOD2, HO-1, SLC2A1, and SCL2A3 genes (p &lt; 0.05). These data demonstrated that dietary supplementation with resveratrol can improve placental function with ameliorated insulin resistance, oxidative stress, and inflammation potentially by regulating Ruminococcaceae UCG-008 and the Christensensllaceae R-7 group in sows.

Nutritional strategies to alleviate oxidative stress in sows

The performance of high-yielding sows is directly related to the productivity of pig farming. Fetal development mainly occurs during the last month of pregnancy, and the aggressive metabolic burden of sows during this stage eventually leads to systemic oxidative stress. When affected by oxidative stress, sows exhibit adverse symptoms such as reduced feed intake, hindered fetal development, and even abortion. In addition, milk synthesis during the lactation period causes a severe metabolic burden. The biological response to oxidative stress during this period is associated with a decrease in milk production, which further affects the growth of piglets. Understanding the nutritional strategies to alleviate oxidative stress in sows is crucial to maintain their reproduction and lactation performance. Recently, advances have been made in the field of nutrition to relieve oxidative stress in sows during late pregnancy and lactation. This review highlights the nutritional strategies to relieve oxidative stress in sows reported within the last 20 years.

Dietary ferulic acid and vanillic acid on inflammation, gut barrier function and growth performance in lipopolysaccharide-challenged piglets

Ferulic acid (FA) and vanillic acid (VA) are considered as major phenolic metabolites of cyanidin 3-glucoside, a polyphenol that widely exists in plants that possess a protective effect against oxidative stress and inflammation in our previous study. This study aimed to investigate the effect of FA and VA on inflammation, gut barrier function, and growth performance in a weaned piglet model challenged with lipopolysaccharide (LPS). Thirty-six piglets (PIC 337 × C48, 28 d of age) were randomly allocated into 3 treatments with 6 replicate pens (2 piglets per pen). They were fed with a basal diet or a diet containing 4,000 mg/kg of FA or VA. Dietary supplementation of VA significantly increased average daily gain (ADG) (P < 0.05). Both FA and VA decreased serum levels of thiobarbituric acid reactive substances (TBARS), interlukin (IL)-1β, IL-2, IL-6, and tumor necrosis factor (TNF)-α (P < 0.05), and enhanced the expression of tight junction protein oclaudin (P < 0.05). Analysis of gut microbiota indicated that both FA and VA increased the Firmicutes/Bacteroidetes ratio alongside reducing the relative abundance of the Prevotellaceae family including Prevotella 9 and Prevotella 2 genera, but enriched the Lachoiraceaea family including the Lachnospiraceae FCS020 group (P < 0.05). Moreover, VA reduced the relative abundance of Prevotella 7 and Prevotella 1 but enriched Lachnospira, Eubacterium eligens group, and Eubacterium xylanophilum group (P < 0.05), while FA showed a limited effect on these genera. The results demonstrated that both VA and FA could alleviate inflammation and oxidative stress, but only VA has a significant positive effect on the growth performance of LPS-challenged piglets potentially through modulating gut microbiota.

Dietary β-Carotene on Postpartum Uterine Recovery in Mice: Crosstalk Between Gut Microbiota and Inflammation

As the precursor of vitamin A, β-carotene has a positive effect on reproductive performance. Our previous study has shown that β-carotene can increase antioxidant enzyme activity potentially through regulating gut microbiota in pregnant sows. This study aimed to clarify the effect of β-carotene on reproductive performance and postpartum uterine recovery from the aspect of inflammation and gut microbiota by using a mouse model. Twenty-seven 6 weeks old female Kunming mice were randomly assigned into 3 groups (n=9), and fed with a diet containing 0, 30 or 90 mg/kg β-carotene, respectively. The results showed that dietary supplementation of β-carotene reduced postpartum uterine hyperemia and uterine mass index (P<0.05), improved intestinal villus height and villus height to crypt depth ratio, decreased serum TNF-α and IL-4 concentration (P<0.05), while no differences were observed in litter size and litter weight among three treatments. Characterization of gut microbiota revealed that β-carotene up-regulated the relative abundance of genera Akkermansia, Candidatus Stoquefichus and Faecalibaculum, but down-regulated the relative abundance of Alloprevotella and Helicobacter. Correlation analysis revealed that Akkermansia was negatively correlated with the IL-4 concentration, while Candidatus Stoquefichus and Faecalibaculum had a negative linear correlation with both TNF-α and IL-4 concentration. On the other hand, Alloprevotella was positively correlated with the TNF-α, and Helicobacter had a positive correlation with both TNF-α and IL-4 concentration. These data demonstrated that dietary supplementation of β-carotene contributes to postpartum uterine recovery by decreasing postpartum uterine hemorrhage and inhibiting the production of inflammatory cytokines potentially through modulating gut microbiota.

Role of Food Antioxidants in Modulating Gut Microbial Communities: Novel Understandings in Intestinal Oxidative Stress Damage and Their Impact on Host Health

Dietary components have an important role on the structure and function of host gut microbial communities. Even though, various dietary components, such as carbohydrates, fats, proteins, fibers, and vitamins, have been studied in depth for their effect on gut microbiomes, little attention has been paid regarding the impact of several food antioxidants on the gut microbiome. The long-term exposure to reactive oxygen species (ROS) can cause microbial dysbiosis which leads to numerous intestinal diseases such as microbiota dysbiosis, intestinal injury, colorectal cancers, enteric infections, and inflammatory bowel diseases. Recently, it has been shown that the food derived antioxidant compounds might protect the host from intestinal oxidative stress via modulating the composition of beneficial microbial species in the gut. The present review summarizes the impact of food antioxidants including antioxidant vitamins, dietary polyphenols, carotenoids, and bioactive peptides on the structure as well as function of host gut microbial communities. Several in vitro, animal model, and clinical studies indicates that food antioxidants might modify the host gut microbial communities and their health status. However, still further clarification is needed as to whether changes in certain microbial species caused by food additives may lead to changes in metabolism and immune function.