Responses in ileal and cecal bacteria to low and high amylose/amylopectin ratio diets in growing pigs

Effects of supplemental bacteriophage on the gut microbiota and nutrient digestibility of ileal-cannulated pigs

This study measured the potential changes of the microbiota in the gastrointestinal tract and energy and nutrient digestibility by supplemental bacteriophages in pigs. Twelve castrated male pigs (initial mean body weight = 29.5 ± 2.3 kg) were surgically cannulated using T-cannula. The animals were housed individually in pens equipped with a feeder and a nipple waterer. The pigs were allotted to 1 of 3 experimental diets in a quadruplicated 3 × 2 Latin square design with 3 experimental diets, 2 periods, and 12 pigs resulting in 8 replicates per diet. The 3 diets were a control mainly based on corn and soybean meal with no antibiotics or bacteriophages, a diet containing 0.1% antibiotics, and a diet containing 0.2% bacteriophages. On day 5 of the experimental period, feces were collected and on days 6 and 7, ileal digesta were collected. Genomic DNA for bacteria were extracted from the ileal digesta and feces and the V4 region of the 16S rRNA gene was amplified. The ileal and fecal digestibility of energy, dry matter, organic matter, crude protein, and fiber was unaffected by dietary antibiotics or bacteriophages. At the phylum level, the supplemental antibiotic or bacteriophage tended to result in a higher proportion of Firmicutes (p = 0.059) and a lower proportion of Bacteroidetes (p = 0.099) in the ileal digesta samples compared with the control group with no difference between the antibiotic and bacteriophage groups. At the genus level, the supplemental antibiotic or bacteriophage tended to result in a higher proportion of Lactobacillus (p = 0.062) and a lower proportion of Bacteroides (p = 0.074) and Streptococcus (p = 0.088) in the ileal digesta compared with the control group with no difference between the antibiotic and bacteriophage groups. In the feces, supplemental antibiotics or bacteriophages reduced the proportion of Bifidobacterium compared with the control group (p = 0.029) with no difference between the antibiotic and bacteriophage groups. Overall, supplemental antibiotics and bacteriophages showed positive effect on the microbiota of in the ileal digesta without largely affecting energy or nutrient digestibility, with no differences between the antibiotic and bacteriophage groups in growing pigs.

Effects of dietary dihydromyricetin supplementation on intestinal barrier and humoral immunity in growing-finishing pigs

In this study, we investigated the effect of dietary dihydromyricetin (DHM) supplementation on intestinal barrier and humoral immunity in growing-finishing pigs. The data showed that dietary DHM supplementation improved jejunal barrier function by upregulating the protein expressions of Occludin and Claudin-1 and the mRNA levels of MUC1 and MUC2. Dietary DHM supplementation increased the amylase, lipase, sucrase and maltase activities and the mRNA expression of nutrient transporter (SGLT1, GLUT2, PepT1) in the jejunum mucosa. Dietary DHM supplementation significantly reduced the E. coli population in the cecum and colon and increased the Lactobacillus population in the cecum. In addition, dietary DHM supplementation increased the contents of butyric acid and valeric acid in cecum and colon. In serum, dietary DHM supplementation reduced interleukin-1β (IL-1β) content and increased interleukin-10 (IL-10), Immunoglobulin M (IgM) and Immunoglobulin A (IgA) contents (p < 0.05). In addition, compared with the control group, dietary DHM supplementation improved secretory immunoglobulin A (sIgA) and interleukin-10 (IL-10) contents and down-regulated TNF-α protein expression in jejunum mucosa (p < 0.05). Together, this study demonstrated that dietary DHM supplementation improved intestinal barrier function, digestion and absorption capacity and immune function in growing-finishing pigs.

The Responses of Lactobacillus reuteri LR1 or Antibiotic on Intestinal Barrier Function and Microbiota in the Cecum of Pigs

This study aimed to investigate responses of the Lactobacillus reuteri or an antibiotic on cecal microbiota and intestinal barrier function in different stages of pigs. A total of 144 weaned pigs (Duroc × Landrace × Yorkshire, 21 days of age) were randomly assigned to the control group (CON, fed with a basal diet), the antibiotic group (AO, fed with basal diet plus 100 mg/kg olaquindox and 75 mg/kg aureomycin), and the L. reuteri group (LR, fed with the basal diet + 5 × 10¹⁰ CFU/kg L. reuteri LR1) throughout the 164-d experiment. A total of 45 cecal content samples (5 samples per group) from different periods (14th, 42th, and 164th days) were collected for 16S rRNA gene amplification. The results revealed that although LR and AO did not change the diversity of cecal microbiota in pigs, the abundance of some bacteria at the genus level was changed with age. The proportion of Lactobacillus was increased by LR in early life, whereas it was decreased by AO compared with the control group. The relative abundance of Ruminococcaceae was increased along with age. In addition, the gas chromatography results showed that age, not AO or LR, has significant effects on the concentrations of SCFAs in the cecum of pigs (P < 0.05). However, the mRNA expression of tight junction proteins zonula occluden-1 (ZO-1) and occludin were increased by AO in the cecum of pigs on day 14, while LR increased the mRNA expression of intestinal barrier-related proteins ZO-1, occludin, mucin-1, mucin-2, PG1-5, and pBD2 in the cecum of pigs on days 14 and 164 (P < 0.05). In conclusion, LR and AO have different effects on the intestinal barrier function of the cecum, and neither LR nor AO damaged the intestinal barrier function of pig cecum. In addition, LR and AO have little effects on cecal microflora in different stages of the pigs. The microflora and their metabolite SCFAs were significantly changed along with age. These findings provide important information to understand the homeostasis of the cecum of pigs after antibiotic or probiotic treatment.

Comparison of the performance of MS enteroscope series and Japanese double- and single-balloon enteroscopes

BACKGROUND

Small intestine disease endangers human health and is not easy to locate and diagnose.

AIM

To observe the effect of the MS series of small intestine endoscopes on the gastrointestinal tract, the changes in serum gastrin levels and intestinal tissue, and the time required for the examination.

METHODS

In vivo experiments in 20 Living pigs were conducted, Bowel preparation was routinely performed, Intravenous anesthesia with propofol and ketamine was applied, the condition of the small intestine was observed and the detection time of the MS series of small intestine endoscopes were recorded, The changes in intestinal tissue using the MS series of small intestine endoscopes observed and compared before and after the examination, Venous blood (3-5 mL) from pigs was collected before and after the experiment; changes in intestinal tissue after use of the MS series of small intestine endoscopes observed after examination. After completion of each type of small intestine endoscope experiment, the pigs were allowed to rest and the next type of small intestine endoscope experiment was performed after 15 days of normal feeding. The detection time data of the single-balloon small intestine endoscope and double-balloon small intestine endoscope were collected from four hospitals.

RESULTS

One case of Ascarislumbricoides, one of suspected Crohn's disease, one small intestinal diverticulum and one anesthesia accident were observed in pigs. The small intestine showed no differences in the MS series of small intestine endoscopes and there were no differences in serum gastrin between the groups (P > 0.05). The time required for inspection was recorded, and the overall detection time for the Japanese small intestine endoscopes was approximately 1.68 ± 0.16 h.

CONCLUSION

Intestinal ascariasis is a common disease in pigs. Some pigs have abnormal intestinal variation. After continuous upgrade and improvement, the MS-3 and MS-4 small intestine endoscope appear superior in terms of detection time.

Differential Effect of Dietary Fibers in Intestinal Health of Growing Pigs: Outcomes in the Gut Microbiota and Immune-Related Indexes

Although dietary fibers (DFs) have been shown to improve intestinal health in pigs, it is unclear whether this improvement varies according to the type/source of DF. In the current study, we investigated the impact of dietary supplement (15%) of pea-hull fiber (PF), oat bran (OB), and their mixture (MIX, PF, and OB each accounted for 7.5%) in the growth performance as well as intestinal barrier and immunity-related indexes in growing pigs. Twenty-four cross-bred pigs (32.42 ± 1.95 kg) were divided into four groups: CON (basal diet with no additional DF), PF, OB, and MIX. After 56 days of feeding, we found that the growth performance of PF pigs was decreased (p < 0.05) compared with pigs in other groups. Results of real-time polymerase chain reaction and Western blot showed that the improvement of immune-related indexes (e.g., interleukin 10 [IL-10]) in OB and MIX pigs mainly presented in the ileum, whereas the improvement of intestinal barrier–related indexes (e.g., MUC1 and MUC2) mainly presented in the colon. Whether in the ileum or colon, such improvement of immune function may be dependent on NOD rather than TLR-associated pathways. Amplicon sequencing results showed that PF and MIX pigs shared a similar bacterial community, such as lower abundance of ileal Clostridiaceae and colonic Streptoccocus than that of CON pigs (p < 0.05). Our results indicate that OB and MIX, rather than PF, benefit the intestinal health in growing pigs, and multiple-sourced DF may reduce the adverse effect of single-soured DF on the growth performance and gut microbiota in pigs.

Fermented Alfalfa Meal Instead of "Grain-Type" Feedstuffs in the Diet Improves Intestinal Health Related Indexes in Weaned Pigs

Corn and soybean meal are the two main components in formula feed of farm animals, leading to a serious food competition between humans and livestock. An alternative may be to encourage the utilization of unconventional feedstuff in animal diet. In the current study, we evaluated the utilization of fermented alfalfa meal (FAM) in weaned pigs. Twenty weaned piglets (separately caged) were randomly divided into two groups. Pigs in the control group (CON) were fed corn-soybean meal diet, and part of corn and soya protein concentrate in the diet of another group was replaced by 8% FAM. After 40 days of feeding, the average feed intake of FAM pigs was increased (P > 0.05), and the villus height (VH) of jejunum and duodenum, crypt depth (CD), and VH/CD in FAM pigs was improved compared to the CON group (P < 0.05). The increase (P < 0.05) of goblet cells in the jejunum of FAM pigs was positively correlated with the expression of MUC-2 gene (R = 0.9150). The expression of genes related to immunity (IRAK4, NF-κB, and IL-10) and intestinal barrier (Occludin and MUC-2) in the jejunum, as well as the expression of ZO-1 and MUC-2 in the colon of these pigs, also showed increase (P < 0.05) compared to CON pigs, which was accompanied by the decrease (P < 0.05) of LPS concentration in the serum. The elevated proportion of CD3+ and CD8+ T-lymphocyte subsets in spleen (P < 0.05) confirmed the improvement of systemic immune function in FAM pigs. In addition, FAM pigs have a higher β-diversity of microbial community (P < 0.05) and promoted enrichment of probiotics such as Lactobacillus that positively was correlated with acetate concentration in the colon over CON pigs. In summary, partially replacement of expanded corn and soya protein concentrate with FAM (8%) may benefit the intestinal barrier and immune function of weaned pigs without affecting their growth. Our findings also provide evidence of the feasibility of FAM as a dietary component in pigs to reduce the consumption of grain.

The Nutritional Significance of Intestinal Fungi: Alteration of Dietary Carbohydrate Composition Triggers Colonic Fungal Community Shifts in a Pig Model

Carbohydrates represent the most important energy source in the diet of humans and animals. A large number of studies have shown that dietary carbohydrates (DCHO) are related to the bacterial community in the gut, but their relationship with the composition of intestinal fungi is still unknown. Here, we report the response of the colonic fungal community to different compositions of DCHO in a pig model. Three factors, ratio (2:1, 1:1, and 1:2) of amylose to amylopectin (AM/AP), level of nonstarch polysaccharides (NSP; 1%, 2%, and 3%), and mannan-oligosaccharide (MOS; 400, 800, and 1,200 mg/kg body weight), were considered according to an L9 (3⁴) orthogonal design to form nine diets with different carbohydrate compositions. Sequencing based on an Illumina HiSeq 2500 platform targeting the internal transcribed spacer 1 region showed that the fungal community in the colon of the pigs responded to DCHO in the order of MOS, AM/AP, and NSP. A large part of some low-abundance fungal genera correlated with the composition of DCHO, represented by Saccharomycopsis, Mrakia, Wallemia, Cantharellus, Eurotium, Solicoccozyma, and Penicillium, were also associated with the concentration of glucose and fructose, as well as the activity of β-d-glucosidase in the colonic digesta, suggesting a role of these fungi in the degradation of DCHO in the colon of pigs. Our study provides direct evidence for the relationship between the composition of DCHO and the fungal community in the colon of pigs, which is helpful to understand the function of gut microorganisms in pigs.IMPORTANCE Although fungi are a large group of microorganisms along with bacteria and archaea in the gut of monogastric animals, the nutritional significance of fungi has been ignored for a long time. Our previous studies revealed a distinct fungal community in the gut of grazing Tibetan pigs (J. Li, D. Chen, B. Yu, J. He, et al., Microb Biotechnol 13:509-521, 2020, https://doi.org/10.1111/1751-7915.13507) and a close correlation between fungal species and short-chain fatty acids, the main microbial metabolites of carbohydrates in the hindgut of pigs (J. Li, Y. Luo, D. Chen, B. Yu, et al., J Anim Physiol Anim Nutr 104:616-628, 2020, https://doi.org/10.1111/jpn.13300). These groundbreaking findings indicate a potential relationship between intestinal fungi and the utilization of DCHO. However, no evidence directly proves the response of intestinal fungi to changes in DCHO. Here, we show a clear alteration of the colonic fungal community in pigs triggered by different compositions of DCHO simulated by varied concentrations of starch, nonstarch polysaccharides (NSP), and oligosaccharides. Our results highlight the potential involvement of intestinal fungi in the utilization of nutrients in monogastric animals.

Carbohydrates effects on nutrition and health functions in pigs

The greatest improvement in carbohydrates studies on pig nutrition and health is that carbohydrates are classified more clearly, which is based not only on their chemical structure but also on their physiological characteristics. Besides its primary energy source, different types and structures of carbohydrates are a benefit for nutrition and health functions in pigs, which are involved in promoting growth performance and intestinal functions, regulating the community of gut microbiota, and modulating the lipids and glucose metabolism. The underlying mechanism of carbohydrates regulates the lipids and glucose metabolism through their metabolites (short-chain fatty acids [SCFAs]) and mainly via the SCFAs-GPR43/41-PYY/GLP1, SCFAs-AMP/ATP-AMPK, and SCFAs-AMPK-G6Pase/PEPCK pathways. Emerging research had evaluated an optimal combination in different types and structures of carbohydrates, which could enhance growth performance and nutrient digestibility, promote intestinal functions, and increase the abundances of butyrate-producing bacteria in pigs. Overall, compelling evidence supports the notion that carbohydrates play important roles in both nutrition and health functions in pigs. Moreover, identifying the carbohydrates combinations will be of both theoretical and practical values for developing the technology of carbohydrates balance in pigs.

Prevotella-rich enterotype may benefit gut health in finishing pigs fed diet with a high amylose-to-amylopectin ratio

To investigate the influence of baseline enterotypes and dietary starch type on the concentration of short-chain fatty acids (SCFA), numbers of butyrate producing bacteria and the expression of genes related to intestinal barrier and inflammatory response in the colon of finishing pigs, a 60-d in vivo trial was conducted. A 2-wk pre-trial with 102 crossbred (Duroc × [Landrace × Yorkshire]) finishing barrows (90 d old) was conducted to screen enterotypes. Then, a total of 32 pigs (87.40 ± 2.76 kg) with high (HPBR, ≥ 14) and low (LPBR, ≤ 2) Prevotella-to-Bacteroides ratios (PBR) in equal measure were selected and randomly divided into 4 groups with 8 replicates per group and 1 pig per replicate. The trial was designed following a 2 (PBR) × 2 (amylose-to-amylopectin ratio, AMR) factorial arrangement. Pigs with different PBR were fed diets based on corn-soybean meal with high AMR (HAMR, 1.24) or low AMR (LAMR, 0.23), respectively. Results showed that neither PBR nor AMR influenced the growth performance of pigs. HPBR pigs fed HAMR diet had a higher number of colonic Clostridium cluster XIVa and higher gene expression of butyrate kinase compared to the LPBR pigs (P < 0.05). The HPBR pigs fed HAMR diets also had increased colonic concentrations of total SCFA and propionate compared to the LPBR pigs (P < 0.05). Comparing with other pigs, HPBR pigs fed HAMR diets showed a lower (P < 0.05) expression of histone deacetylases (HDAC) gene and higher (P < 0.05) expression of G protein-coupled receptor 43 gene (GPR 43) in the colonic mucosa. The interaction (P < 0.05) of HPBR and HAMR was also found to decrease the gene expression of interleukin (IL)-6, IL-12, IL-1β and tumor necrosis factor-α (TNF-α) in colonic mucosa. These findings show that HAMR diet increased the abundance and activity of butyrate-producing bacteria and the concentration and absorption of SCFA, which may be associated with the decreased gene expression of inflammatory cytokines in the colonic mucosa of pigs with Prevotella-rich enterotype. All these alterations are likely to have a positive effect on the intestinal health of finishing pigs.

The combination of nutraceuticals and functional feeds as additives modulates gut microbiota and blood markers associated with immune response and health in weanling piglets

This study aimed to evaluate the effects of a combination of feed additives with complementary functional properties on the intestinal microbiota, homocysteine, and vitamins E and B status as well as systemic immune response of weanling piglets. At weaning, 32 litters were assigned to one of the following dietary treatments (DT): 1) conventional diet (CTRL); 2) CTRL diet supplemented with antibiotics (ATB); 3) a cocktail of feed additives containing cranberry extract, encapsulated carvacrol, yeast-derived products, and extra vitamins A, D, E, and B complex (CKTL); or 4) CKTL diet with bovine colostrum in replacement of plasma proteins (CKTL + COL). Within each litter, the piglets with lowest and highest birth weights (LBW and HBW, respectively) and two piglets of medium birth weight (MBW) were identified. The MBW piglets were euthanized at 42 d of age in order to characterize the ileal and colonic microbiota. Blood samples were also collected at weaning and at 42 d of age from LBW and HBW piglets to measure insulin-like growth factor-1 (IGF-1), cysteine, homocysteine, and vitamins E, B₆, and B₁₂, and to characterize the leukocyte populations. At 42 d of age, cytokine production by stimulated peripheral blood mononuclear cells was also measured. In a second experiment, piglets were reared under commercial conditions to evaluate the effects of the DT on the growth performance. At the indicator species analysis, the highest indicator value (IV) for Succinivibrio dextrinosolvens was found in the CKTL group, whereas the highest IV for Lactobacillus reuteri and Faecalibacterium prausnitzii was evidenced in the CKTL + COL group (P < 0.05). Compared with the other DT, CTRL piglets had higher concentrations of homocysteine, whereas the CKTL and CKTL + COL supplementations increased the concentrations of vitamins E and B₁₂ (P < 0.05). DT had no effect on IGF-1 concentration and on blood leukocytes populations; however, compared with HBW piglets, LBW animals had lower values of IGF-1, whereas the percentages of γδ T lymphocytes and T helper were decreased and increased, respectively (P < 0.05). CKTL + COL also improved the growth performance of piglets reared under commercial conditions (P < 0.05). This study highlights the impact of birth weight on piglet systemic immune defenses and the potential of weaning diet supplemented with feed additives and bovine colostrum to modulate the homocysteine metabolism and the intestinal microbiota.

The Optimal Combination of Dietary Starch, Non-Starch Polysaccharides, and Mannan-Oligosaccharide Increases the Growth Performance and Improves Butyrate-Producing Bacteria of Weaned Pigs

Simple Summary

Information about the optimal carbohydrate combination for pigs is scarce. This present study explored the effects of different combinations of starch, non-starch polysaccharides, and mannan-oligosaccharide on the growth performance, nutrient digestibility, and microbial communities in weaned pigs, which contributed a novel way of evaluating the carbohydrate quality of the diet for pigs.

Abstract

The present experiment was conducted to dissect the effects of different carbohydrate combinations on the growth performance, nutrient digestibility, and microbial communities in weaned pigs. The combination was optimized by constructing L₉(3⁴) orthogonal design. Three factors include starch (amylose to amylopectin (AM/AP) ratio 2:1, 1:1, 1:2), non-starch polysaccharides (NSP) (1%, 2%, 3%, a mixture of inulin with cellulose by 1:1), and mannan-oligosaccharide (MOS) (400, 800, 1200 mg/kg) were investigated and nine combinations were implemented under different levels of these factors. One hundred and sixty-two weaned pigs were randomly assigned to nine dietary treatments with six replicates per treatment and three pigs per replicate. Results exhibited that different combinations of starch, NSP, and MOS affected the gain to feed (G:F) (p < 0.05), diarrhea incidence (p < 0.10), nutrient digestibility (p < 0.05), microbial communities, and short-chain fatty acid (SCFA) concentrations (p < 0.05). In the present study, taking into account three-way ANOVA, range, and direct analysis, we found that the optimal carbohydrate combination was starch AM/AP 1:1, NSP 3%, MOS 400 mg/kg for weaned pigs. Moreover, feeding this combination diet could promote the growth performance and nutrient digestibility, increase the butyrate-producing bacteria, and to some extent improve lipid metabolism. This study provided a novel way to evaluate the carbohydrate quality in swine production.

Pectin and inulin stimulated the mucus formation at a similar level: An omics-based comparative analysis

Mucin 2 (MUC2) is the skeleton of colonic mucus that comprises the physical intestinal barrier. Different dietary polysaccharides may affect colonic mucus at different extents. The effect of pectin on MUC2 production is contradictory. To investigate whether and how pectin affected hosts' colonic mucus, the amount of MUC2 in colon, the cecal, mucosal microbiota, and metabolites profiles were analyzed and compared with inulin. The results showed pectin stimulated the production of MUC2 at a similar level to inulin. Both interventions increased the abundance of cecal Lachnospira and Christensenellaceae_R-7_group, and enhanced the production of specific metabolites including soyasapogenol B 24-O-b-d-glucoside, lucyoside Q, trans-EKODE-(E)-Ib, and 1,26-dicaffeoylhexacosanediol. Additionally, pectin increased the relative abundance (RA) of cecal Lactobacillus, and induced less RA of potentially harmful bacteria such as Helicobacter in mucosal microbiota than inulin. In conclusion, we first reported that pectin and inulin stimulated the mucus formation at a similar level. Two genera of cecal bacteria and four metabolites may play an important role in enhancing the production of MUC2. Moreover, the MUC2 production may be unrelated to several traditional health-beneficial bacteria; pectin possibly performed as good as or better than the inulin in rats' gut.

Effects of dietary inulin supplementation on growth performance, intestinal barrier integrity and microbial populations in weaned pigs

Here, we explored the influences of dietary inulin (INU) supplementation on growth performance and intestinal health in a porcine model. Thirty-two male weaned pigs (with an average body weight of 7·10 (sd 0·20) kg) were randomly assigned to four treatments and fed with a basal diet (BD) or BD containing 2·5, 5·0 and 10·0 g/kg INU. After a 21-d trial, pigs were killed for collection of serum and intestinal tissues. We show that INU supplementation had no significant influence on the growth performance in weaned pigs. INU significantly elevated serum insulin-like growth factor-1 concentration but decreased diamine oxidase concentration (P < 0·05). Interestingly, 2·5 and 5·0 g/kg INU supplementation significantly elevated the villus height in jejunum and ileum (P < 0·05). Moreover, 2·5 and 5·0 g/kg INU supplementation also elevated the villus height to crypt depth (V:C) in the duodenum and ileum and improved the distribution and abundance of tight-junction protein zonula occludens-1 in duodenum and ileum epithelium. INU supplementation at 10·0 g/kg significantly elevated the sucrase activity in the ileum mucosa (P < 0·05). INU supplementation decreased the expression level of TNF-α but elevated the expression level of GLUT 2 and divalent metal transporter 1 in the intestinal mucosa (P < 0·05). Moreover, INU increased acetic and butyric acid concentrations in caecum (P < 0·05). Importantly, INU elevated the Lactobacillus population but decreased the Escherichia coli population in the caecum (P < 0·05). These results not only indicate a beneficial effect of INU on growth performance and intestinal barrier functions but also offer potential mechanisms behind the dietary fibre-regulated intestinal health.

Effects of Dietary Starch Structure on Growth Performance, Serum Glucose-Insulin Response, and Intestinal Health in Weaned Piglets

Simple Summary

Carbohydrates are the most important energy source for monogastric animals, including humans, and dysregulation of carbohydrate metabolism has been associated with metabolic syndromes, such as type 2 diabetes mellitus (T2DM), hypertension, and obesity. Starch is the major carbohydrate source, consisting of amylose and amylopectin. This study investigated the effects of dietary starch structure on growth performance, serum glucose–insulin response, and intestinal health in weaned piglets, which may contribute to the principles of carbohydrate nutrition and facilitate the utilization of dietary starches.

Abstract

To investigate the effects of dietary starch structure (amylose/amylopectin ratio, AR) on serum glucose absorption metabolism and intestinal health, a total of ninety weaned piglets (Duroc × (Yorkshire × Landrace)) were randomly assigned to 5 dietary treatments and fed with a diet containing different AR (2.90, 1.46, 0.68, 0.31, and 0.14). The trial lasted for 21 d. In this study, the growth performance was not affected by the dietary starch structure (p > 0.05). Diets with higher amylose ratios (i.e., AR 2.90 and 1.46) led to a significant reduction of the serum glucose concentration at 3 h post-prandium (p < 0.01), while high amylopectin diets (AR 0.31 and 0.14) significantly elevated The expression of gene s at this time point (p < 0.01). High amylopectin diets also increased the apparent digestibility of crude protein (CP), ether extract (EE), dry matter (DM), gross energy (GE), and crude ash (p < 0.001). Interestingly, diet rich in amylose (AR 2.90) significantly elevated the butyric acid content (p < 0.05) and decreased the pH value (p < 0.05) in the cecal digesta. In contrast, diet rich in amylopectin (i.e., AR 0.14) significantly elevated the total bacteria populations in the cecal digesta (p < 0.001). Moreover, a high amylopectin diet (AR 0.14) tended to elevate the mRNA level of fatty acid synthase (FAS, p = 0.083), but significantly decreased the mRNA level of sodium-dependent glucose transporter 1 (SGLT1, p < 0.05) in the duodenal and jejunal mucosa, respectively. These results suggested that blood glucose and insulin concentrations were improved in high AR diets, and the diet also helped to maintain the intestinal health.

Ruminal microbiome-host crosstalk stimulates the development of the ruminal epithelium in a lamb model

BACKGROUND

The development of the rumen is an important physiological challenge for young ruminants. Previous studies have shown that starter feeding can effectively facilitate the growth and development of the rumen in ruminants. However, the mechanism through which starter feeding stimulates the development of the rumen is not clear. Here, we performed an integrated analysis in ruminal microbiota and a host transcriptomic profile in a lamb model with the intervention of starter feed to understand the ruminal microbiome-host crosstalk in stimulating the development of the ruminal epithelium.

RESULTS

Decreased ruminal pH and increased acetate and butyrate concentrations in the rumen, followed by increasing rumen organ index, were observed in lambs supplemented with starter. Using metagenome sequencing in combination with 16S rRNA and 18S rRNA gene amplicon sequencing, the results showed the abundance of acetate-producing Mitsuokella spp., lactate-producing Sharpea spp., lactate-utilizing Megasphaera spp., and Entodinium spp. was enriched in rumen microbial communities in the starter-feed group. The abundances of genes involved in sugar degradation were decreased in starter-feed lambs, but the GH13 encoding α-amylase was obviously increased. Rumen epithelial transcriptome analysis revealed that seven differentially expressed genes, including MAPK1, PIK3CB, TNFSF10, ITGA6, SNAI2, SAV1, and DLG, related to the cell growth module were upregulated, and BAD's promotion of cell death was downregulated. Correlation analysis revealed that the increase in the concentrations of acetate and butyrate significantly correlated with the expression of these genes, which indicates acetate and butyrate likely acted as important drivers in the ruminal microbiome-host crosstalk.

CONCLUSIONS

The present study comprehensively describes the symbiotic relationship between the rumen microbiota and the host in lambs after starter feeding. Our data demonstrates that the microbiome-driven generation of acetate and butyrate mediated the growth-related genes' regulation of the growth-associated signalling pathway in the ruminal epithelium. These co-development networks regulated many physiological processes in the epithelium, including papillae morphology and rumen epithelial growth.

Microbiome-Metabolomics Analysis Investigating the Impacts of Dietary Starch Types on the Composition and Metabolism of Colonic Microbiota in Finishing Pigs

The present study used a combination of 16S rRNA MiSeq sequencing strategy and gas chromatograph time of flight mass spectrometer (GC-TOF/MS) technique to investigate the effects of starch sources on the colonic microbiota and their metabolites in finishing pigs. A total of 72 crossbred barrows were allocated to three different experimental diets with eight replicates and three pigs per replicate. The diet types included tapioca starch (TS), corn starch (CS), and pea starch (PS) (amylose/amylopectin were 0.11, 0.25, and 0.44, respectively). Results showed that the PS diet markedly increased (adjusted P < 0.05) the abundance of short-chain fatty acids (SCFAs) and lactate producers, such as Lactobacillus, Prevotella, Faecalibacterium, and Megasphaera, while decreased (adjusted P < 0.05) the abundance of Escherichia coli when compared with the TS diet. The metabolomic and biochemistry analyses demonstrated that the PS diet increased (adjusted P < 0.05) the concentrations of organic acids (acetate, propionate, butyrate, valerate, and lactate) and some macronutrients (sugars and long-chain fatty acids), and decreased (adjusted P < 0.05) the amino acids and their derivatives (leucine, glycine, putrescine, cadaverine, skatole, indole, and phenol) when compared with the TS diet. Additionally, Spearman’s correlation analysis revealed that the changes in the colonic metabolites were associated with changes in the microbial composition. Correlatively, these findings demonstrated that the different dietary starch types treatment significantly altered the intestinal microbiota and metabolite profiles of the pigs, and dietary with higher amylose may offer potential benefits for gut health.

Diquat-induced oxidative stress increases intestinal permeability, impairs mitochondrial function, and triggers mitophagy in piglets

In the present study, we investigated the influence of diquat-induced oxidative stress on intestinal barrier, mitochondrial function, and the level of mitophagy in piglets. Twelve male Duroc × Landrace × Yorkshire 35-d-old pigs (weaned at 21 d of age), with an average body of 9.6 kg, were allotted to two treatments of six piglets each including the challenged group and the control group. The challenged pigs were injected with 100 mg/kg bodyweight diquat and control pigs injected with 0.9% (w/v) NaCl solution. The results showed that diquat injection decreased ADFI and ADG. Diquat decreased (P < 0.05) the activities of superoxide dismutase and glutathione peroxidase and increased (P < 0.05) the malondialdehyde concentrations. The lower (P < 0.05) transepithelial electrical resistance and higher (P < 0.05) paracellular permeability of fluorescein isothiocyanatedextran 4 kDa were found in diquat challenged piglets. Meanwhile, diquat decreased (P < 0.05) the protein abundance of claudin-1, occluding, and zonula occludens-1 in jejunum compared with the control group. Diquat-induced mitochondrial dysfunction, as demonstrated by increased (P < 0.05) reactive oxygen species production and decreased (P < 0.05) membrane potential of intestinal mitochondria. Diquat-injected pigs revealed a decrease (P < 0.05) of mRNA abundance of genes related to mitochondrial biogenesis and functions, PPARg coactivator-1α, mammalian-silencing information regulator-1, nuclear respiratory factor-1, mt transcription factor A, mt single-strand DNA-binding protein, mt polymerase r, glucokinase, citrate synthase, ATP synthase, and cytochrome coxidase subunit I and V in the jejunum. Diquat induced an increase (P < 0.05) in expression of mitophagy-related proteins, phosphatase and tensin homologue deleted on chromosome 10-induced putative kinase, and Parkin in the intestinal mitochondria, as well as an enhancement of the ratio of light chain 3-II (LC3-II) to LC3-I content in the jejunal mucosa. These results suggest that oxidative stress disrupted the intestinal barrier, caused mitochondrial dysfunction, and triggered mitophagy.

Weaning disrupts intestinal antioxidant status, impairs intestinal barrier and mitochondrial function, and triggers mitophagy in piglets

In the present study, we investigated the influence of weaning on antioxidant status, intestinal integrity, mitochondrial function, and the mitophagy level in piglets (weaned at 21 d) during the 1 wk after weaning. The redox status was measured by antioxidant enzymes activities, related genes expression, and malondialdehyde (MDA) content in jejunum. The intestinal barrier function was assessed by the Ussing chamber and expression of tight junction proteins in the jejunum. The function of intestine mitochondria was measured by mitochondrial DNA (mtDNA) content and activities of mitochondria oxidative phosphorylation complexes. The levels of light chain 3-1 (LC3-I), light chain 3-II (LC3-II), PTEN-induced putative kinase 1 (PINK1), and Parkin were determined to investigate whether mitophagy is involved in the weaning process. The results showed that, as compared with the preweaning phase (d 0), weaning suppressed (P < 0.05) the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) on d 3 and d 7 postweaning, decreased (P < 0.05) the expression of copper and zinc superoxide dismutase (Cu/Zn-SOD), manganese-containing superoxide dismutase (Mn-SOD) on d 3 postweaning, declined (P < 0.05) the level of glutathione peroxidase 1 (GPX-1) and glutathione peroxidase 4 (GPX-4) on d 3 and d 7 postweaning, and increased (P < 0.05) MDA content in jejunum on d 3 and d 7 postweaning. The jejunal transepithelial electrical resistance and levels of occludin, claudin-1, and zonula occludens-1 on d 3 and d 7 postweaning were reduced (P < 0.05), and paracellular flux of fluorescein isothiocyanatedextran (4 kDa) on d 3 and d 7 postweaning was increased (P < 0.05). Weaning induced mitochondrial dysfunction, as demonstrated by decreased (P < 0.05) content of mtDNA on d 3 and d 7 postweaning and declined (P < 0.05) activities of mitochondria complexes (I, II, III, IV) in jejunum on d 1, d 3, and d 7 postweaning. Weaning led to an increased (P < 0.05) expression level of mitophagy-related proteins, PINK1 and Parkin, in the intestinal mitochondria, as well as an enhancement (P < 0.05) of the ratio of LC3-II to LC3-I content in the jejunal mucosa on d 1, d 3, and d 7 postweaning. These results suggest that weaning disrupted intestinal oxidative balance, and this imbalance may impair intestinal barrier and mitochondrial function and trigger mitophagy in piglets.

Different Types of Dietary Fibers Trigger Specific Alterations in Composition and Predicted Functions of Colonic Bacterial Communities in BALB/c Mice

Soluble dietary fibers (SDF) are fermented more than insoluble dietary fibers (IDF), but their effect on colonic bacterial community structure and function remains unclear. Thus, bacterial community composition and function in the colon of BALB/c mice (n = 7) fed with a high level (approximately 20%) of typical SDF, oat-derived β-glucan (G), microcrystalline cellulose (M) as IDF, or their mixture (GM), were compared. Mice in group G showed a lowest average feed intake (p < 0.05) but no change on the average body weight gain (p > 0.05) compared to other groups, which may be associated with the highest concentration of colonic propionate (p < 0.05) in these mice. The bacterial α-diversity of group G was significantly lower than other groups (p < 0.01). In group G, the relative abundance of bacteria belonging to the phylum Bacteroidetes was significantly increased, whereas bacteria from the phylum Firmicutes were significantly decreased (p < 0.01). The core bacteria for different treatments showed distinct differences. Bacteroides, Dehalobacterium, and Prevotella, including known acetogens and carbohydrate fermenting organisms, were significantly increased in relative abundance in group G. In contrast, Adlercreutzia, Odoribacter, and Coprococcus were significantly more abundant in group M, whereas Oscillospira, Desulfovibrio, and Ruminoccaceae, typical hydrogenotrophs equipped with multiple carbohydrate active enzymes, were remarkably enriched in group GM (p < 0.05). The relative abundance of bacteria from the three classes of Proteobacteria, Betaproteobacteria, Gammaproteobacteria (including Enterobacteriaceae) and Deltaproteobacteria, were significantly more abundant in group G, indicating a higher ratio of conditional pathogenic bacteria in mice fed dietary β-glucan in current study. The predicted colonic microbial function showed an enrichment of “Energy metabolism” and “Carbohydrate metabolism” pathways in mice from group G and M, suggesting that the altered bacterial community in the colon of mice with the two dietary fibers probably resulted in a more efficient degradation of dietary polysaccharides. Our result suggests that the influence of dietary β-glucan (SDF) on colonic bacterial community of mice was more extensively than MCC (IDF). Co-supplementation of the two fibers may help to increase the bacterial diversity and reduce the conditional pathogens in the colon of mice.

Meta-analysis To Define a Core Microbiota in the Swine Gut

The swine gut microbiota encompasses a large and diverse population of bacteria that play a significant role in pig health. As such, a number of recent studies have utilized high-throughput sequencing of the 16S rRNA gene to characterize the composition and structure of the swine gut microbiota, often in response to dietary feed additives. It is important to determine which factors shape the composition of the gut microbiota among multiple studies and if certain bacteria are always present in the gut microbiota of swine, independently of study variables such as country of origin and experimental design. Therefore, we performed a meta-analysis using 20 publically available data sets from high-throughput 16S rRNA gene sequence studies of the swine gut microbiota. Next to the "study" itself, the gastrointestinal (GI) tract section that was sampled had the greatest effect on the composition and structure of the swine gut microbiota (P = 0.0001). Technical variation among studies, particularly the 16S rRNA gene hypervariable region sequenced, also significantly affected the composition of the swine gut microbiota (P = 0.0001). Despite this, numerous commonalities were discovered. Among fecal samples, the genera Prevotella, Clostridium, Alloprevotella, and Ruminococcus and the RC9 gut group were found in 99% of all fecal samples. Additionally, Clostridium, Blautia, Lactobacillus, Prevotella, Ruminococcus, Roseburia, the RC9 gut group, and Subdoligranulum were shared by >90% of all GI samples, suggesting a so-called "core" microbiota for commercial swine worldwide. IMPORTANCE The results of this meta-analysis demonstrate that "study" and GI sample location are the most significant factors in shaping the swine gut microbiota. However, in comparisons of results from different studies, some biological factors may be obscured by technical variation among studies. Nonetheless, there are some bacterial taxa that appear to form a core microbiota within the swine GI tract regardless of country of origin, diet, age, or breed. Thus, these results provide the framework for future studies to manipulate the swine gut microbiota for potential health benefits.

Addition of arabinoxylan and mixed linkage glucans in porcine diets affects the large intestinal bacterial populations

PURPOSE

To investigate the effects of two cereal soluble dietary fibres (SDF), wheat arabinoxylan (AX) and oat-mixed linkage glucans (MLG), on fermentative end-products and bacterial community profiles of the porcine caecum (Cae) and distal colon (DC). We hypothesised that feeding pigs these SDF would stimulate Cae and DC carbohydrate fermentation, resulting in a modification of the resident bacterial communities.

METHODS

Five groups of six pigs were each fed one diet based on wheat starch (WS) only, or treatment diets in which some WS was replaced by 10 % AX, or 10 % MLG, a combination of 5 % AX:5 % MLG (AXMLG), or completely replaced with ground whole wheat. Post-euthanasia, Cae and DC digesta were collected for analysis of fermentative end-products, and bacterial community profiles were determined by 16S rRNA gene amplicon 454 pyrosequencing.

RESULTS

Across all the SDF-containing diets, predominantly in the proximal region of the large intestine, Prevotella, Lactobacillus, Mitsuokella and Streptococcus were most significantly influenced (P < 0.05), while notable changes were observed for the Ruminococcaceae and Lachnospiraceae families in the Cae and DC. The addition of MLG or AXMLG had the greatest effect of influencing bacterial profiles, reducing sequence proportions assigned to the genus Clostridium, considered detrimental to gut health, with associated increases in short-chain fatty acid and reduced ammonia concentrations.

CONCLUSIONS

This study demonstrated how the cereal SDF AX and MLG altered the large intestinal bacterial community composition, particularly proximally, further giving insights into how diets rich in specific complex carbohydrates shift the bacterial population, by increasing abundance and promoting greater diversity of those bacteria considered beneficial to gut health.