Stimulation of butyrate production through the metabolic interaction among lactic acid bacteria, Lactobacillus acidophilus, and lactic acid-utilizing bacteria, Megasphaera elsdenii, in porcine cecal digesta

Influence of chain length on the colonic fermentation of xylooligosaccharides

Xylooligosaccharides (XOS) have been employed as prebiotics containing oligomers of varying sizes or molecular ratios. XOS with a low degree of polymerization (DP) has been demonstrated to have high prebiotic potential. However, there is limited information regarding the specific chain length of XOS required to elicit distinct responses in the gut microbiota. In this study, we aimed to explore whether variations in XOS DP could alter the fate of colonic fermentation. Five XOS fractions (BWXFs) with DP ranges of >40, 20-40, 10-20, 5-10, and 2-4 were prepared by beechwood xylan autohydrolysis and tested on human gut microbiota. Extracellular XOS degradation was observed for molecules with a DP exceeding 5. BWXF treatments altered the microbial community structures, and substrate size-dependent effects on the microbial composition and metabolic outputs were observed. Bacteroidaceae were specifically enriched by xylan. Lachnospiraceae were particularly stimulated by XOS with a DP of 20-40 and 2-4. Bifidobacteriaceae were notably enriched by XOS with a DP of 5-20. High butyrate yields were obtained from cultures containing long-chain BWXFs. Microbiota responses differed with XOS DP composition changes, and microbial competition with XOS with a DP of 2-4 requires further exploration.

Fine-tuning of post-weaning pig microbiome structure and functionality by in-feed zinc oxide and antibiotics use

Introduction

Post-weaning diarrhoea (PWD) is a multifactorial disease that affects piglets after weaning, contributing to productive and economic losses. Its control includes the use of in-feed prophylactic antibiotics and therapeutic zinc oxide (ZnO), treatments that, since 2022, are no longer permitted in the European Union due to spread of antimicrobial resistance genes and pollution of soil with heavy metals. A dysbiosis in the microbiota has been suggested as a potential risk factor of PWD onset. Understanding pig's microbiota development around weaning and its changes in response to ZnO and antibiotics is crucial to develop feasible alternatives to prophylactic and metaphylactic antimicrobial use.

Methods

This study used shotgun metagenomic sequencing to investigate the environmental and faecal microbiota on 10 farms using (Treated) or not using (ZnO-free) in-feed antibiotics and ZnO during the first 14 days post-weaning (dpw). Environmental samples from clean pens were collected at weaning day (0dpw), and faecal samples at 0, 7 and 14dpw. Diarrhoeic faecal samples were collected at 7dpw when available.

Results

The analysis of data revealed that the faecal microbiota composition and its functionality was impacted by the sampling time point (microbiota maturation after weaning) but not by the farm environment. Treatment with antibiotics and ZnO showed no effects on diversity indices while the analyses of microbiota taxonomic and functional profiles revealed increased abundance of taxa and metabolic functions associated with Phascolarctobacterium succinatutens or different species of Prevotella spp. on the Treated farms, and with Megasphaera elsdenii and Escherichia coli on the ZnO-free farms. The analysis of diarrhoea samples revealed that the treatment favoured the microbiota transition or maturation from 0dpw to 14dpw in Treated farms, resembling the composition of healthy animals, when compared to diarrhoea from ZnO-free farms, which were linked in composition to 0dpw samples.

Discussion

The results provide a comprehensive overview of the beneficial effects of ZnO and antibiotics in PWD in the microbiota transition after weaning, preventing the overgrowth of pathogens such as pathogenic E. coli and revealing the key aspects in microbiota maturation that antibiotics or ZnO alternatives should fulfil.

Identification of intestinal and fecal microbial biomarkers using a porcine social stress model

Understanding the relationships between social stress and the gastrointestinal microbiota, and how they influence host health and performance is expected to have many scientific and commercial implementations in different species, including identification and improvement of challenges to animal welfare and health. In particular, the study of the stress impact on the gastrointestinal microbiota of pigs may be of interest as a model for human health. A porcine stress model based on repeated regrouping and reduced space allowance during the last 4 weeks of the finishing period was developed to identify stress-induced changes in the gut microbiome composition. The application of the porcine stress model resulted in a significant increase in salivary cortisol concentration over the course of the trial and decreased growth performance and appetite. The applied social stress resulted in 32 bacteria being either enriched (13) or depleted (19) in the intestine and feces. Fecal samples showed a greater number of microbial genera influenced by stress than caecum or colon samples. Our trial revealed that the opportunistic pathogens Treponema and Clostridium were enriched in colonic and fecal samples from stressed pigs. Additionally, genera such as Streptococcus, Parabacteroides, Desulfovibrio, Terrisporobacter, Marvinbryantia, and Romboutsia were found to be enriched in response to social stress. In contrast, the genera Prevotella, Faecalibacterium, Butyricicoccus, Dialister, Alloprevotella, Megasphaera, and Mitsuokella were depleted. These depleted bacteria are of great interest because they synthesize metabolites [e.g., short-chain fatty acids (SCFA), in particular, butyrate] showing beneficial health benefits due to inhibitory effects on pathogenic bacteria in different animal species. Of particular interest are Dialister and Faecalibacterium, as their depletion was identified in a human study to be associated with inferior quality of life and depression. We also revealed that some pigs were more susceptible to pathogens as indicated by large enrichments of opportunistic pathogens of Clostridium, Treponema, Streptococcus and Campylobacter. Generally, our results provide further evidence for the microbiota-gut-brain axis as indicated by an increase in cortisol concentration due to social stress regulated by the hypothalamic-pituitary-adrenal axis, and a change in microbiota composition, particularly of bacteria known to be associated with pathogenicity and mental health diseases.

Deep insight into oriented propionate production from food waste: Microbiological interpretation and design practice

Using mixed microbial cultures (MMCs) for oriented volatile fatty acids (VFAs) refining in an open environment is a typical challenge due to the microbial diversiform and the process complexity. Especially for carbohydrate-rich waste (such as food waste), butyrate-type fermentation is usually dominant in a single-stage MMCs anaerobic process, while the production of odd-carbon VFAs (such as propionate) is difficult although it plays a significant role in chemicals industries. In this study, firstly, we gave a new perspective on the rationality of the oriented propionate production using MMCs with lactate as feedstock by conducting in-depth microbial informatics and reaction analysis. Secondly, we verified the feasibility of the "food waste-lactate-propionate" route to reverse the original butyrate-type fermentation situation and explore mechanisms for maintaining stability. In the first stage, a defined lactate fermentation microbiome was used to produce lactate-containing broth (80% of total chemical oxygen demand) at pH=4. In the second stage, an undomesticated undefined anaerobic microbiome was used to drive propionate production (45.26% ± 2.23% of total VFAs) under optimized conditions (C/N = 100:1-200:1 and pH=5.0). The low pH environment in the first stage enhanced the lactic acid bacteria to resist the invasion of non-functional flanking bacteria, making the community stable. In the second stage, the system maintained the propionate-type fermentation due to the absence of the ecological niche of the invasive lactic acid bacteria; The selection of propionate-producing specialists was a necessary but not sufficient condition for propionate-type fermentation. At last, this study proposed an enhanced engineering strategy framework for understanding elaborate MMCs fermentation.

Evaluating lactation performance of multiparous dairy cattle to prepartum and/or postpartum supplementation of fat-embedded calcium gluconate

Prebiotic compounds may be supplemented in the diet to improve animal health and performance in a variety of ways. In dairy cattle, the transition from pregnancy through parturition and lactation represents a critical life stage with many concurrent stressors. The objectives of this study were to evaluate responses to the provision of a hindgut-targeted prebiotic compound (calcium gluconate; HFCG) when supplemented prepartum and/or postpartum in a 2 × 2 factorial design. One hundred and sixty-four multiparous Holstein cattle were enrolled and followed from approximately 21 d prior to calving until 100 d of lactation. Treatments were administered as a pelleted compound feed offered in the rotary milking parlor once daily prepartum and thrice daily postpartum. Information pertaining to milk production and body weight were automatically recorded by the milking equipment, and information pertaining to reproductive and health performance was recorded by farm staff. Cattle that received HFCG prepartum were confirmed pregnant approximately 21 d earlier (P = 0.024). Cattle that received HFCG both pre- and postpartum had 9% to 10% higher yields of milk protein, fat, and energy-corrected milk (P ≤ 0.037) from weeks 4 to 9 of lactation relative to those that received HFCG exclusively prepartum. Conversely, cattle that received HFCG exclusively postpartum had 9% to 10% higher yields of milk protein, fat, and energy-corrected milk (P ≤ 0.037) from weeks 9 to 14 of lactation relative to those that received exclusively the negative control in both periods. The mechanism underlying these responses remains unclear, however, we hypothesize that these responses are due to localized reductions in inflammation in the gut and/or signaling to extragastrointestinal tissues altering energy partitioning and balance.

Gluconic acid improves performance of newly weaned piglets associated with alterations in gut microbiome and fermentation

BACKGROUND

Weaning is a critical phase in the pigs' life and gut health might be compromised. Gluconic acid was shown to be poorly absorbed but readily fermented to butyrate in the gut which in turn can improve gut function. Hence, a total of 144 weaning pigs were fed the experimental diets for 42 days. Three treatments were replicated in 8 pens with 6 piglets each: control; low dietary dose of gluconic acid, 9 g/kg; and high dietary dose of gluconic acid, 18 g/kg. After 21 days, one piglet from each pen was sampled for blood haematology and biochemistry, fore- and hindgut digesta characteristics and microbiota, and distal small intestinal histo-morphological indices and gene expression.

RESULTS

Feeding gluconic acid enhanced performance in period d 0-14 post-weaning, in particular feed intake was increased (P = 0.028), though the high dose did not show benefits over the low dose. Regarding d 0-42, feed intake was elevated (P = 0.026). At d 21, piglets fed 18 g/kg gluconic acid showed a trend for lower number of total white blood cells (P = 0.060), caused by particularly lower numbers of lymphocytes as compared to control (P = 0.028). Highly reduced plasma urea was found for groups fed gluconic acid, it amounted to 2.6 and 2.6 mmol/L for the 9 and 18 g/kg level, respectively, as compared to 3.8 mmol/L in control (P = 0.003). Feeding gluconic acid promoted the relative abundance of lactic-acid-producing and acid-utilizing bacteria. In distal small intestine, Lactobacillus amylovorus increased substantially from 11.3 to 82.6% for control and gluconic acid 18 g/kg, respectively (P < 0.05). In mid-colon, the butyrate producers Faecalibacterium prausnitzii (P > 0.05) and Megasphaera elsdenii (P < 0.05) showed highest abundance in gluconic acid 18 g/kg. Consequently, in caecum and mid-colon, increased relative molar percentage of butyrate were found, e.g., 10.0, 12.9 et 14.7% in caecum for gluconic acid at 0, 9, and 18 g/kg, respectively (P = 0.046). Elevated mRNA anti-inflammatory cytokine and survival signalling levels in distal small intestinal mucosa were found by feeding gluconic acid which might be mediated by butyrate.

CONCLUSIONS

Gluconic acid may have potential to alleviate the postweaning growth-check in pigs by altering microbiota composition and fermentation in the gut.

Supplementation of hydrogenated fat-embedded calcium gluconate improves milk fat content and yield in multiparous Holstein dairy cattle

This research communication reports the responses to supplementing dairy cattle with a hydrogenated fat-embedded calcium gluconate feed additive. The role of hindgut health in ruminant performance and wellbeing is an area of growing interest. Various prebiotic compounds have been used to promote lower gut health in various non-ruminant species. Calcium gluconate, a prebiotic compound, has previously been observed to increase milk fat yield when fed to ruminants in a form capable of resisting fermentation in the rumen, though the mechanism(s) behind this response remain unclear. The objective of this study was to compare the responses of lactating cattle to two different supplementation levels of a hydrogenated fat-embedded calcium gluconate (HFCG) product to evaluate a potential linear dose response. Forty-six lactating Holstein dairy cattle were used in a 3 × 3 replicated Latin square design with 28 d periods to evaluate a previously used dose of HFCG (approximately 16 g/d) with both a negative control and a dose of 25 g/d. Supplementation of multiparous animals with 16 g/d HFCG significantly (P < 0.05) increased milk fat yield and content relative to the negative control, and subsequently improved gross feed efficiency (P < 0.05); additionally, the presence of a potential non-linear dose response was observed for these parameters. Responses when supplemented with 25 g/d HFCG did not differ from the negative control. No production responses were observed in primiparous animals. The mode of action of HFCG, in addition to the potential differential response in primiparous animals remains unclear and warrants further investigation.

Effect of hydrogenated fat-embedded calcium gluconate on lactation performance in dairy cows

Hydrogenated fat-embedded calcium gluconate (HFCG), a prebiotic mixture designed to target the hindgut, has improved milk and component yields when supplemented in mid-lactation cows, likely due to improved hindgut health. The objective of this study was to evaluate production responses to HFCG when fed to lactating dairy cattle over a full lactation. Seventy-four Holstein cows (21 primiparous, 53 multiparous) were used in a randomized complete block design comparing supplementation with either HFCG (approximately 16 g/d of supplement delivering approximately 6.4 g of active ingredient) or a negative control from approximately 21 days prior to calving until the end of lactation. In multiparous cattle supplemented with HFCG, average daily milk protein yield (P = 0.037) was increased during the first 8 weeks of lactation, while average daily yields of milk fat, fat- and energy-corrected milk tended (P ≤ 0.075) to increase over the same period of time. Increased yields were likely supported by the concurrent increase in dry matter intake (P = 0.036). Future work is needed to characterize the mode of action of this product within both the hindgut lumen and host, as well as investigate the potential differential responses between primiparous and multiparous animals over the course of lactation.

Effect of Feeding Calcium Gluconate Embedded in a Hydrogenated Fat Matrix on Feed Intake, Gastrointestinal Fermentation and Morphology, Intestinal Brush Boarder Enzyme Activity and Blood Metabolites in Growing Lambs

Gluconate salts have been identified as a butyrate precursor when fed to non-ruminant species and may increase the butyrate concentration in the large intestine supporting gastrointestinal health and development. The objective of this study was to evaluate the dose response of hydrogenated fat-embedded calcium gluconate (HFCG) on performance and gastrointestinal tract (GIT) development in growing lambs. Thirty-two wether lambs were used in a randomized complete block design and assigned to 1 of 4 treatments differing in the inclusion of HFCG: 0.0% (CON), 0.075% (LOW), 0.30% (MED), and 0.60% of the diet (HIGH). Lambs were allocated into individual pens and fed ad libitum with feed delivered twice daily. Feed intake was recorded daily, and body weight (BW) was assessed at the beginning and the end of the 29-d period. Blood was sampled on d 21, prior to feeding and 6 h post-feeding to evaluate changes in β-hydroxybutyrate, glucose, and insulin concentrations. Total fecal collection was conducted during d 25 to 28 to assess apparent total tract digestibility. On d 29, lambs were slaughtered, and the entire GIT was separated by region to enable sampling of tissue and digesta. Data were analyzed to assess linear, quadratic, and cubic effects of HFCG dose. Final BW, average daily gain, and dry matter intake decreased linearly (P ≤ 0.02) with increasing HFCG. Increasing inclusion of HFCG linearly decreased (P = 0.01) the thickness of the stratum corneum in ruminal papillae but did not affect other strata (P ≥ 0.34). Omasal digesta weight linearly decreased (P = 0.01) as the concentration of HFCG increased and abomasal digesta weight was cubically affected (P = 0.03) the increasing dose of HFCG. Short-chain fatty acid concentration in the cecum was cubically affected (P < 0.01) with increasing dose of HFCG where low dose had the greatest concentration. Moreover, increasing the dietary supply of HFCG linearly increased the proportion of acetate (P = 0.04) in the cecum and linearly decreased the proportion of propionate in the digesta of both the cecum (P < 0.01) and colon (P = 0.01). Colon crypt depth was quadratically (P = 0.03) affected with the increasing dose of HFCG, where lambs fed MED had greatest crypt depth. We conclude that feeding HFCG to growing lambs did not increase butyrate concentration in the large intestine and consequently does not increase the absorptive surface area of the whole tract, the size of the GIT, or the functionality of the intestine.

Galacto-oligosaccharides improve barrier function and relieve colonic inflammation via modulating mucosa-associated microbiota composition in lipopolysaccharides-challenged piglets

BACKGROUND

Galacto-oligosaccharides (GOS) have been shown to modulate the intestinal microbiota of suckling piglets to exert beneficial effects on intestinal function. However, the modulation of intestinal microbiota and intestinal function by GOS in intestinal inflammation injury models has rarely been reported. In this study, we investigated the effects of GOS on the colonic mucosal microbiota composition, barrier function and inflammatory response of lipopolysaccharides (LPS)-challenged suckling piglets.

METHODS

A total of 18 newborn suckling piglets were divided into three groups, the CON group, the LPS-CON group and the LPS-GOS group. Piglets in the LPS-GOS group were orally fed with 1 g/kg body weight of GOS solution every day. On the d 14, piglets in the LPS-CON and LPS-GOS group were challenged intraperitoneally with LPS solution. All piglets were slaughtered 2 h after intraperitoneal injection and sampled.

RESULTS

We found that the colonic mucosa of LPS-challenged piglets was significantly injured and shedding, while the colonic mucosa of the LPS-GOS group piglets maintained its structure. Moreover, GOS significantly reduced the concentration of malondialdehyde (MDA) and the activity of reactive oxygen species (ROS) in the LPS-challenged suckling piglets, and significantly increased the activity of total antioxidant capacity (T-AOC). GOS significantly increased the relative abundance of norank_f__Muribaculaceae and Romboutsia, and significantly decreased the relative abundance of Alloprevotella, Campylobacter and Helicobacter in the colonic mucosa of LPS-challenged suckling piglets. In addition, GOS increased the concentrations of acetate, butyrate and total short chain fatty acids (SCFAs) in the colonic digesta of LPS-challenged suckling piglets. GOS significantly reduced the concentrations of interleukin 1β (IL-1β), interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α) and cluster of differentiation 14 (CD14), and the relative mRNA expression of Toll-like receptor 4 (TLR4) and myeloid differentiation primary response 88 (MyD88) in the LPS-challenged suckling piglets. In addition, GOS significantly reduced the relative mRNA expression of mucin2 (MUC2), and significantly increased the protein expression of Claudin-1 and zonula occluden-1 (ZO-1) in LPS-challenged suckling piglets.

CONCLUSIONS

These results suggested that GOS can modulate the colonic mucosa-associated microbiota composition and improve the intestinal function of LPS-challenged suckling piglets.

Effects of supplemental calcium gluconate embedded in a hydrogenated fat matrix on lactation, digestive, and metabolic variables in dairy cattle

There is growing evidence suggesting that by improving gut integrity and function, less energy is partitioned toward immune responses related to xenobiotic infiltration, sparing energy for productive purposes. Gluconic acid and its salts have previously shown prebiotic effects in the lower gut of nonruminant animals, where they serve as a precursor for butyrate, although evidence in ruminants is limited. Butyrate and its fermentative precursors have demonstrated multiple beneficial effects to gastrointestinal ecology, morphology, and function, such as the stimulation of epithelial cell proliferation and improvement of gut barrier function and ecology. The objective of this study was to evaluate changes in milk production, milk fatty acid composition, and fecal and blood parameters in lactating dairy cattle fed a hydrogenated fat-embedded calcium gluconate (HFCG) supplement designed to target the hindgut for calcium gluconate delivery. In addition, the effects of a compound feed processing method (i.e., incorporated into a mash or an extruded pellet) were tested to evaluate the effect of extrusion on product efficacy. Forty-five lactating Holstein cows at approximately 165 d in milk were used in a 3 × 3 Latin square consisting of three 28-d periods, during which animals were offered a basal ration mixed with 3 different compound feeds: a negative control in mash form containing no HFCG, or the HFCG supplement fed at a target rate of 16 g/d, delivered in either a mash or pelleted form. Supplementation of HFCG tended to increase yields of milk fat and fat- and energy-corrected milk. Total yields and concentrations of milk fatty acids ≥18 carbons in length tended to increase in response to HFCG. Plasma nonesterified fatty acids and milk urea increased in HFCG treatments. No differences were observed in fecal pH or fecal concentrations of volatile fatty acids, with the exception of isobutyrate, which decreased in HFCG-fed cows. Changes in milk fatty acid profile suggest that increased milk fat yield was driven by increased incorporation of preformed fatty acids, supported by increased circulating nonesterified fatty acid. Future research investigating the mode of action of HFCG at the level of the hindgut epithelium is warranted, as measured fecal parameters showed no response to treatment.

Targeting the Hindgut to Improve Health and Performance in Cattle

An adequate gastrointestinal barrier function is essential to preserve animal health and well-being. Suboptimal gut health results in the translocation of contents from the gastrointestinal lumen across the epithelium, inducing local and systemic inflammatory responses. Inflammation is characterized by high energetic and nutrient requirements, which diverts resources away from production. Further, barrier function defects and inflammation have been both associated with several metabolic diseases in dairy cattle and liver abscesses in feedlots. The gastrointestinal tract is sensitive to several factors intrinsic to the productive cycles of dairy and beef cattle. Among them, high grain diets, commonly fed to support lactation and growth, are potentially detrimental for rumen health due to their increased fermentability, representing the main risk factor for the development of acidosis. Furthermore, the increase in dietary starch associated with such rations frequently results in an increase in the bypass fraction reaching distal sections of the intestine. The effects of high grain diets in the hindgut are comparable to those in the rumen and, thus, hindgut acidosis likely plays a role in grain overload syndrome. However, the relative contribution of the hindgut to this syndrome remains unknown. Nutritional strategies designed to support hindgut health might represent an opportunity to sustain health and performance in bovines.

Comparison of the fecal microbiota of two monogastric herbivorous and five omnivorous mammals

Fecal microbiota in seven different monogastric animal species, elephant, horse, human, marmoset, mouse, pig and, rat were compared using the same analytical protocol of 16S rRNA metagenome. Fecal microbiota in herbivores showed higher alpha diversity than omnivores except for pigs. Additionally, principal coordinate analysis based on weighted UniFrac distance demonstrated that herbivores and pigs clustered together, whereas other animal species were separately aggregated. In view of butyrate- and lactate-producing bacteria, predominant genera were different depending on animal species. For example, the abundance of Faecalibacterium, a known butyrate producer, was 8.02% ± 3.22% in human while it was less than 1% in other animal species. Additionally, Bifidobacterium was a predominant lactate producer in human and marmoset, while it was rarely detected in other omnivores. The abundance of lactate-producing bacteria in herbivores was notably lower than omnivores. On the other hand, herbivores as well as pig possess Fibrobacter, a cellulolytic bacterium. This study demonstrated that fecal microbiota in herbivorous animals is similar, sharing some common features such as higher alpha diversity and higher abundance of cellulolytic bacterium. On the other hand, omnivorous animals seem to possess unique fecal microbiota. It is of interest that pigs, although omnivore, have fecal microbiota showing some common features with herbivores.

Intestinal microbiota control acute kidney injury severity by immune modulation

Intestinal microbiota impacts the host immune system and influences the outcomes of chronic diseases. However, it remains uncertain whether acute kidney injury (AKI) impacts intestinal microbiota or vice versa. To determine this, we investigated the mechanistic link between AKI, microbiota, and immune response in ischemia/reperfusion injury. Microbiota alteration and its biological consequences after ischemia/reperfusion injury were examined and the effect of dysbiotic microbiota on the outcome of AKI was also assessed by colonizing germ-free mice with post-AKI microbiota. The role of Th17, Th1, Tregs cells and macrophage polarization in mediating the renoprotective effect of antibiotic induced microbiota depletion in ischemia/reperfusion injury was also determined. Increase of Enterobacteriacea, decrease of Lactobacilli, and Ruminococacceae were found to be the hallmarks of ischemia/reperfusion injury induced dysbiosis and were associated with a decreased levels of short-chain fatty acids, intestinal inflammation and leaky gut. Colonizing germ-free mice with post-AKI microbiota worsened ischemia/reperfusion injury severity with exaggerated inflammation in recipient mice compared to colonizing with microbiota from sham operated mice. Microbiota depletion by oral antibiotics protected against ischemia/reperfusion injury. This renoprotective effect was associated with reduced Th 17, Th 1 response along with expansion of regulatory T cells, and M2 macrophages. Our study demonstrated a unique bidirectional relationship between the kidney and the intestine during AKI. Intestinal dysbiosis, inflammation and leaky gut are consequences of AKI but they also represent an important modifier determining post-AKI severity. Thus, targeting the intestinal microbiota might provide a novel therapeutic strategy in AKI.

Lactobacillus paracasei subsp. paracasei NTU 101 lyophilized powder improves loperamide-induced constipation in rats

Constipation is a condition of the digestive system characterized by formation of hard feces that are difficult to eliminate. It has emerged as a new problem that is commonly encountered by many people and lifestyle changes have been unsuccessful in providing a solution. This study aimed to investigate the effects of Lactobacillus paracasei subsp. paracasei NTU 101 on loperamide-induced constipated rats and on gastrointestinal tract function. Sprague-Dawley rats were administered loperamide (2 mg/kg BW) twice daily as well as 1.3, 2.6, and 13.0 mg/kg BW/rat/d of NTU 101 powder. The control, positive control, and NTU 101 powder groups (0.5, 1, 5×) showed improved intestinal mobility with a statistically significant increase of 12.4%, 14.7%, 12.5%, 13.4%, and 15.1%, respectively (p < 0.05); the fecal water content was also significantly increased by 11.7%, 9.0%, 10.0%, 9.3%, and 11.0%, respectively (p < 0.05), compared to the loperamide group. Furthermore, NTU 101 increased the Bifidobactrium spp. and decreased the Clostridium perfringens content in feces; it increased short-chain fatty acid levels, reduced fecal pH value, enhanced the thickness of the colonic mucosa, and increased the number of mucin-producing goblet cells and interstitial cells of Cajal. Thus, NTU 101 powder was found to alleviate loperamide-induced constipation and improve gastrointestinal tract function.

Gut microbiota and butyrate level changes associated with the long-term administration of proton pump inhibitors to old rats

The association between adverse effects of PPI and gut microbiota in old age has yet to be elucidated. We assessed changes in the gut microbiota and butyrate levels following the long-term administration of PPIs to old rats and investigated their associations. F344 aged male rats were fed a PPI-supplemented diet for 50 weeks. The ileal microbiota was analysed by metagenomic sequencing of the 16S rRNA, while the butyrate concentration was measured by high-performance liquid chromatography. We observed a significant decrease in microbial diversity following PPI administration in the 2-year-old rats but not in the 74-week-old rats. PPI treatment reduced both commensal bacteria and opportunistic pathogens, particularly in the 2-year-old rats. Enterotypes comprising the majority of the control samples were enriched in Lactobacillus, while other enterotypes in the PPI group were dominated by Turicibacter or Romboutsia. The PPI treatment reduced the butyrate concentrations in the intestines and colons of 74-week-old rats compared to the control group. The abundance of Lactobacillus significantly correlated with butyrate concentrations in 74-week-old rats. In conclusion, long-term administration of PPIs alters the gut microbiota and butyrate concentrations in rats, particularly in old age, which may be an underlying mechanism of PPI-induced adverse effects such as pseudomembranous colitis.

Kazachstania turicensis CAU Y1706 ameliorates atopic dermatitis by regulation of the gut-skin axis

Atopic dermatitis (AD) causes chronic inflammatory skin disease that results in a considerable economic expense and social burden. Certain Lactobacillus strains ameliorate AD, but the effects of probiotic yeast on AD have not been investigated to date. In this study, we isolated Kazachstania turicensis CAU Y1706, commonly known as a kefir yeast, and evaluated its mitigating effects using an ovalbumin-sensitized AD mouse model. Overall, K. turicensis CAU Y1706 was generally effective against AD. Oral administration of K. turicensis CAU Y1706 suppressed T helper type 2 immune response factors by regulatory T cells and upregulation of T helper type 1 cytokine levels. Kazachstania turicensis CAU Y1706 also reduced IgE levels as well as the number of eosinophil and mast cells. Furthermore, feces from K. turicensis CAU Y1706-treated mice had more butyrate-producing bacteria, such as Lactobacillus, Bacteroides, Ruminococcus, and Akkermansia, although the level of Fecalibacterium was significantly reduced. Therefore, K. turicensis CAU Y1706 modulates immune responses as well as gut microbiota, thus indicating that it has potential for application as a supplement for alleviation of AD.

Qi-Deficiency Related Increases in Disease Susceptibility Are Potentially Mediated by the Intestinal Microbiota

Qi-deficiency (QX) is thought to promote the body's susceptibility to disease, but the underlying mechanism through which this occurs is not clear. We surveyed the traditional Chinese medicine constitution (TCMC) of healthy college students to identify those that were PH (balanced TCMC constitution) and QX (unbalanced TCMC constitution). We then used high-throughput sequencing of the 16SrRNA V3-4 region in fecal microbiota samples to identify differences between those obtained from PH and QX individuals. Our results demonstrated that the alpha diversity of QX samples was significantly lower than that of PH samples (p < 0.05) and that beta diversity was remarkably different in QX and PH samples. Four and 122 bacterial taxa were significantly overrepresented in QX and PH groups, respectively. The genera Sphingobium, Clostridium, and Comamonas were enriched in the QX group and had a certain pathogenic role. The QX group also showed a statistically significant lack of probiotics and anti-inflammatory bacteria such as Bifidobacterium and Bdellovibrio. The functional potential of QX bacterial taxa was reduced in fatty acid metabolism and butanoate metabolism. We contend that the imbalanced intestinal microbiota in QX and the following functional changes in metabolism influence immunity and energy metabolism, which could increase susceptibility to disease.

Transglycosylated Starch Modulates the Gut Microbiome and Expression of Genes Related to Lipid Synthesis in Liver and Adipose Tissue of Pigs

Dietary inclusion of resistant starches can promote host health through modulation of the gastrointestinal microbiota, short-chain fatty acid (SCFA) profiles, and lipid metabolism. This study investigated the impact of a transglycosylated cornstarch (TGS) on gastric, ileal, cecal, proximal-colonic, and mid-colonic bacterial community profiles and fermentation metabolites using a growing pig model. It additionally evaluated the effect of TGS on the expression of host genes related to glucose and SCFA absorption, incretins, and satiety in the gut as well as host genes related to lipid metabolism in hepatic and adipose tissue. Sixteen growing pigs (4 months of age) were fed either a TGS or control (CON) diet for 11 days. Bacterial profiles were determined via Illumina MiSeq sequencing of the V3-5 region of the 16S rRNA gene, whereas SCFA and gene expression were measured using gas chromatography and reverse transcription-quantitative PCR. Megasphaera, which was increased at all gut sites, began to benefit from TGS feeding in gastric digesta, likely through cross-feeding with other microbes, such as Lactobacillus. Shifts in the bacterial profiles from dietary TGS consumption in the cecum, proximal colon, and mid colon were similar. Relative abundances of Ruminococcus and unclassified Ruminococcaceae genus were lower, whereas that of unclassified Veillonellaceae genus was higher in TGS- compared to CON-fed pigs (p < 0.05). TGS consumption also increased (p < 0.05) concentrations of SCFA, especially propionate, and lactate in the distal hindgut compared to the CON diet which might have up-regulated GLP1 expression in the cecum (p < 0.05) and mid colon compared to the control diet (p < 0.10). TGS-fed pigs showed increased hepatic and decreased adipocyte expression of genes for lipid synthesis (FASN, SREBP1, and ACACA) compared to CON-fed pigs, which may be related to postprandial portal nutrient flow and reduced systemic insulin signaling. Overall, our data show that TGS consumption may affect gastrointestinal bacterial signaling, caused by changes in gut bacterial profiles and the action of propionate, and host lipid metabolism.

Nutrient digestibility, hindgut metabolites and antioxidant status of dogs supplemented with pomegranate peel extract

The present study assessed the effect of dietary supplementation of pomegranate peel (methanolic) extract (PPE) on the nutrient digestibility, faecal fermentative metabolites and antioxidant status of dogs. Six medium-sized dogs of mixed breeds were allocated to two groups in a replicated cross-over design and fed a basal diet with and without supplementation of PPE at 50 mg/kg body weight. Each of the experimental periods consisted of 30 d, with a 21 d washout period in between. Results indicated that PPE supplementation led to no significant changes in nutrient digestibility except a trend of improvement (P = 0·070) in crude fibre digestibility. PPE supplementation significantly (P < 0·001) influenced faecal pH, ammonia and lactate production, indicative of positive effects of PPE polyphenols. PPE supplementation further increased faecal SCFA concentration accompanied by a reduction (P < 0·01) in branched-chain fatty acids. PPE supplementation also improved (P < 0·05) indices of erythrocytic antioxidants, namely reduced glutathione, catalase, glutathione peroxidase and glutathione S-transferase together with an improvement in lipid peroxidation. Overall, it can be concluded that dietary supplementation with PPE at 50 mg/kg body weight had a positive impact on hindgut fermentation and antioxidant status in dogs, thereby demonstrating its potential as a gut health-promoting nutraceutical.

Effect of Bacillus subtilis and Bacillus licheniformis supplementation in diets with low- and high-protein content on ileal crude protein and amino acid digestibility and intestinal microbiota composition of growing pigs

Background

Bacillus spp. seem to be an alternative to antimicrobial growth promoters for improving animals’ health and performance. However, there is little information on the effect of Bacillus spp. in combination with different dietary crude protein (CP) levels on the ileal digestibility and microbiota composition. Therefore, the objective of this study was to determine the effect of Bacillus spp. supplementation to low- (LP) and high-protein diets (HP) on ileal CP and amino acid (AA) digestibility and intestinal microbiota composition.

Methods

Eight ileally cannulated pigs with an initial body weight of 28.5 kg were randomly allocated to a row-column design with 8 pigs and 3 periods of 16 d each. The assay diets were based on wheat-barley-soybean meal with two protein levels: LP (14% CP, as-fed) and HP diet (18% CP, as-fed). The LP and HP diets were supplemented with or without Bacillus spp. at a level of 0.04% (as-fed). The apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of CP and AA was determined. Bacterial community composition from ileal digesta was analyzed by Illumina amplicon sequencing and quantitative real-time PCR. Data were analyzed as a 2 × 2 factorial design using the GLIMMIX procedures of SAS.

Results

The supplementation with Bacillus spp. did not affect both AID and SID of CP and AA in growing pigs. Moreover, there was no difference in AID of CP and AA between HP and LP diets, but SID of cystine, glutamic acid, glycine, and proline was lower (P < 0.05) in pigs fed the HP diets. The HP diets increased abundance of Bifidobacterium spp. and Lactobacillus spp., (P < 0.05) and by amplicon sequencing the latter was identified as predominant genus in microbiota from HP with Bacillus spp., whereas dietary supplementation of Bacillus spp. increased (P < 0.05) abundance of Roseburia spp..

Conclusions

The HP diet increased abundance of Lactobacillus spp. and Bifidobacterium spp.. The supplementation of Bacillus spp. resulted in a higher abundance of healthy gut associated bacteria without affecting ileal CP and AA digestibility, whereas LP diet may reduce the flow of undigested protein to the large intestine of pigs.

Production of high-concentration n-caproic acid from lactate through fermentation using a newly isolated Ruminococcaceae bacterium CPB6

BACKGROUND

n-Caproic acid (CA), as a medium-chain carboxylic acid, is a valuable chemical feedstock for various industrial applications. The fermentative production of CA from renewable carbon sources has attracted a lot of attentions. Lactate is a significant intermediate waste in the anaerobic breakdown of carbohydrates that comprise 18-70% of the chemical oxygen demand (COD) in municipal and some industrial wastewaters. Recently, researchers (including our own group) reported the CA production using lactate as electron donor with newly identified microbiome systems. However, within such processes, it was hard to determine whether the CA production was completed by a single strain or by the co-metabolism of different microorganisms.

RESULTS

Here, we report the CA production using lactate as electron donor using the strain CPB6, which we isolated from a microbiome for CA production as described previously. Strain CPB6 is affiliated with Clostridium cluster IV of the family of Ruminococcaceae based on 16S rRNA gene sequence analysis. The strain prefers acidic initial pH condition (pH 5.0-6.5), and the temperature ranging from 30 to 40 °C for CA production. In a fed-batch fermentation with non-sterilized lactate-containing organic wastewater as feedstock, strain CPB6 produced 16.6 g/L CA (from 45.1 g/L lactate) with a maximum productivity of 5.29 g/L/day. Enzyme assays with crude cell extract showed that CPB6 can metabolize acetate and butyryl-CoA to produce n-butyric acid, and acetate/n-butyrate and caproyl-CoA to produce CA, respectively.

CONCLUSION

This study demonstrated that high concentration of CA production can be obtained by a newly isolated pure culture CPB6. This strain can be employed as a powerful workhorse for high-efficient CA recovery from lactate-containing waste streams. Our preliminary investigation suggested that the CA production from lactate in strain CPB6 might be via the chain elongation pathway of the reverse β-oxidation; the detailed mechanism, however, warrants further investigation using various molecular microbiology techniques.

Microbial community structure reveals how microaeration improves fermentation during anaerobic co-digestion of brown water and food waste

The purpose of this study was to investigate the impact of microaeration on the fermentation process during anaerobic co-digestion of brown water (BW) and food waste (FW). This was achieved by daily monitoring of reactor performance and the determination of its bacterial consortium towards the end of the study. Molecular cloning and sequencing results revealed that bacteria within phyla Firmicutes and Bacteriodetes represented the dominant phylogenetic group. As compared to anaerobic conditions, the fermentation of BW and FW under microaeration conditions gave rise to a significantly more diverse bacterial population and higher proportion of bacterial clones affiliated to the phylum Firmicutes. The acidogenic reactor was therefore able to metabolize a greater variety of substrates leading to higher hydrolysis rates as compared to the anaerobic reactor. Other than enhanced fermentation, microaeration also led to a shift in fermentation production pattern where acetic acid was metabolized for the synthesis of butyric acid.

Comparative genome analysis of Megasphaera sp. reveals niche specialization and its potential role in the human gut

With increasing number of novel bacteria being isolated from the human gut ecosystem, there is a greater need to study their role in the gut ecosystem and their effect on the host health. In the present study, we carried out in silico genome-wide analysis of two novel Megasphaera sp. isolates NM10 (DSM25563) and BL7 (DSM25562), isolated from feces of two healthy individuals and validated the key features by in vitro studies. The analysis revealed the general metabolic potential, adaptive features and the potential effects of these isolates on the host. The comparative genome analysis of the two human gut isolates NM10 and BL7 with ruminal isolate Megasphaera elsdenii (DSM20460) highlighted the differential adaptive features for their survival in human gut. The key findings include features like bile resistance, presence of various sensory and regulatory systems, stress response systems, membrane transporters and resistance to antibiotics. Comparison of the “glycobiome” based on the genomes of the ruminal isolate with the human gut isolates NM10 and BL revealed the presence of diverse and unique sets of Carbohydrate-Active enzymes (CAZymes) amongst these isolates, with a higher collection of CAZymes in the human gut isolates. This could be attributed to the difference in host diet and thereby the environment, consequently suggesting host specific adaptation in these isolates. In silico analysis of metabolic potential predicted the ability of these isolates to produce important metabolites like short chain fatty acids (butyrate, acetate, formate, and caproate), vitamins and essential amino acids, which was further validated by in vitro experiments. The ability of these isolates to produce important metabolites advocates for a potential healthy influence on the host. Further in vivo studies including transcriptomic and proteomic analysis will be required for better understanding the role and impact of these Megasphaera sp. isolates NM10 and BL7 on the human host.

Oral administration of Lactobacillus plantarum Lq80 and Megasphaera elsdenii iNP-001 induces efficient recovery from mucosal atrophy in the small and the large intestines of weaning piglets

Weaning causes atrophy of intestinal mucosa and a drop of IgA protection in piglets which increases vulnerability to pathogenic infections. Probiotic lactobacilli may support recovery from such weaning stresses. Butyrate-produce bacteria may support the growth of colonic mucosa. Megasphaera elsdenii, a lactate-utilizing butyrate producer, may help butyrate production particularly when combined with lactobacilli. Weaned piglets (Experiment 1: 20 days old, Experiment 2: 28 days old) were orally dosed once a day with either (L) 10(10) (cell/dose) L. plantarum Lq80, or (LM) 10(10) (cell/dose) Lq80 with 10(9) (cell/dose) M. elsdenii iNP-001. Lq80 was contained in capsules resistant to gastric digestion. M. elsdenii was contained in capsules resistant to gastric and intestinal digestion. An untreated control (C) was also prepared. After 2 weeks of administration, L. plantarum enhanced the recovery from the villous atrophy in both experiments. The rectal and colonic IgA tended to be higher in L and LM than in C in Experiment 1. Colonic butyrate was higher in LM than in the others in Experiment 1. The thickness of the colonic mucosa was greater in LM than in the others in Experiment 1. In early weaned piglets, the effects of L. plantarum and M. elsdenii were clear.

Health-beneficial effects of probiotics: Its mode of action

It is now widely recognized that probiotics have health-beneficial effects on humans and animals. Probiotics should survive in the intestinal tract to exert beneficial effects on the host's health. To keep a sufficient level of probiotic bacteria in the gastrointestinal tract, a shorter interval between doses may be required. Although adherence to the intestinal epithelial cell and mucus is not a universal property of probiotics, high ability to adhere to the intestinal surface might strongly interfere with infection of pathogenic bacteria and regulate the immune system. The administration of probiotic Lactobacillus stimulated indigenous Lactobacilli and the production of short-chain fatty acids. This alteration of the intestinal environment should contribute to maintain the host's health. The immunomodulatory effects of probiotics are related to important parts of their beneficial effects. Probiotics may modulate the intestinal immune response through the stimulation of certain cytokine and IgA secretion in intestinal mucosa. The health-beneficial effects, in particular the immunomodulation effect, of probiotics depend on the strain used. Differences in indigenous intestinal microflora significantly alter the magnitude of the effects of a probiotic. Specific probiotic strains suitable for each animal species and their life stage as well as each individual should be found.

Ileal microbiota of growing pigs fed different dietary calcium phosphate levels and phytase content and subjected to ileal pectin infusion

Two experiments with growing pigs were conducted to determine the effects of dietary P and Ca levels, phytase supplementation, and ileal pectin infusion on changes in bacterial populations in the ileum and on ileal and fecal fermentation patterns. Growing pigs (BW 30.1 +/- 1.3 kg) were fitted with simple T-cannulas at the distal ileum and were fed a low-P corn-soybean meal control diet (3 g of P/kg), or the control diet supplemented with either 15 g of monocalcium phosphate (MCP)/kg (Exp. 1) or 1,000 phytase units of phytase/kg (Exp. 2). Daily infusion treatments consisted of either 60 g of pectin dissolved in 1.8 L of demineralized water or 1.8 L of demineralized water as a control infusion, infused via the ileal cannula. In each experiment, 8 barrows were assigned to 4 dietary treatments according to a double incomplete 4 x 2 Latin square design. The dietary treatments in Exp. 1 were the control diet with water infusion, the control diet with pectin infusion, the MCP diet with water infusion, or the MCP diet with pectin infusion. In Exp. 2, the pigs received the same control treatments as in Exp. 1 and the phytase diet in combination with water or pectin infusion. Gene copy numbers of total bacteria, Lactobacillus spp., Lactobacillus reuteri, Lactobacillus amylovorus/Lactobacillus sobrius, Lactobacillus mucosae, Enterococcus spp., Enterococcus faecium, Enterococcus faecalis, bifidobacteria, the Clostridium coccoides cluster, the Clostridium leptum cluster, the Bacteroides-Prevotella-Porphyrmonas group, and Enterobacteriaceae were determined by quantitative PCR in DNA extracts of ileal digesta. In Exp. 1, addition of MCP reduced ileal gene copy numbers of Enterococcus spp. (P = 0.048), E. faecium (P = 0.015), and the C. leptum cluster (P = 0.028), whereas pectin infusion enhanced (P = 0.008) ileal d-lactate concentration. In Exp. 2, supplemental phytase led to greater ileal gene copy numbers of the C. coccoides (P = 0.041) and C. leptum (P = 0.048) clusters and the Bacteroides-Prevotella-Porphyrmonas group (P = 0.033), whereas it reduced (P = 0.027) fecal n-butyrate concentration. Pectin infusion reduced (P = 0.005) ileal gene copy number of the C. leptum cluster. In conclusion, ileal bacterial populations and fermentation patterns are susceptible to changes in the intestinal availability of Ca and P as well as to the supply of pectin as a fermentable substrate. Greater intestinal Ca availability decreased the numbers of some gram-positive bacteria, whereas greater P availability in the small intestine caused by phytase activity enhanced the growth of strictly anaerobic bacteria.