Effect of dietary β-glucan on growth performance, fecal microbial shedding and immunological responses after lipopolysaccharide challenge in weaned pigs

The Effect of Prebiotic Supplements on the Gastrointestinal Microbiota and Associated Health Parameters in Pigs

Establishing a balanced and diverse microbiota in the GIT of pigs is crucial for optimizing health and performance throughout the production cycle. The post-weaning period is a critical phase, as it is often associated with dysbiosis, intestinal dysfunction and poor performance. Traditionally, intestinal dysfunctions associated with weaning have been alleviated using antibiotics and/or antimicrobials. However, increasing concerns regarding the prevalence of antimicrobial-resistant bacteria has prompted an industry-wide drive towards identifying natural sustainable dietary alternatives. Modulating the microbiota through dietary intervention can improve animal health by increasing the production of health-promoting metabolites associated with the improved microbiota, while limiting the establishment and proliferation of pathogenic bacteria. Prebiotics are a class of bioactive compounds that resist digestion by gastrointestinal enzymes, but which can still be utilized by beneficial microbes within the GIT. Prebiotics are a substrate for these beneficial microbes and therefore enhance their proliferation and abundance, leading to the increased production of health-promoting metabolites and suppression of pathogenic proliferation in the GIT. There are a vast range of prebiotics, including carbohydrates such as non-digestible oligosaccharides, beta-glucans, resistant starch, and inulin. Furthermore, the definition of a prebiotic has recently expanded to include novel prebiotics such as peptides and amino acids. A novel class of -biotics, referred to as "stimbiotics", was recently suggested. This bioactive group has microbiota-modulating capabilities and promotes increases in short-chain fatty acid (SCFA) production in a disproportionally greater manner than if they were merely substrates for bacterial fermentation. The aim of this review is to characterize the different prebiotics, detail the current understating of stimbiotics, and outline how supplementation to pigs at different stages of development and production can potentially modulate the GIT microbiota and subsequently improve the health and performance of animals.

Effects of β-glucan with vitamin E supplementation on the growth performance, blood profiles, immune response, fecal microbiota, fecal score, and nutrient digestibility in weaning pigs

OBJECTIVE

This study was conducted to evaluate effects of β-glucan with vitamin E supplementation on the growth performance, blood profiles, immune response, fecal microbiota, fecal score, and nutrient digestibility in weaning pigs.

METHODS

A total of 200 weaning pigs with an average body weight (BW) of 7.64±0.741 kg were allotted to five treatment groups and were divided based on sex and initial BW in four replicates with ten pigs per pen in a randomized complete block design. The experimental diets included a corn‒soybean meal-based basal diet with or without 0.1% or 0.2% β-glucan and 0.02% vitamin E. The pigs were fed the diets for 6 weeks. A total of 15 barrows were used to evaluate the nutrient digestibility by the total collection method. The BW and feed intake were measured at the end of each phase. Blood samples were collected at the end of each phase, and fecal samples were collected at the end of the experiment.

RESULTS

The addition of β-glucan with vitamin E to weaning pig feed increased BW, average daily gain, and average daily feed intake. A significant decrease in yeast and mold and Proteobacteria and a tendency for Lactobacillus to increase compared to the control was shown when 0.1% β-glucan and 0.02% vitamin E were added. The fecal score in weaning pigs was lower in the treatments supplemented with 0.1% or 0.2% β-glucan and 0.02% vitamin E compared to the control. In addition, vitamin E was better supplied to weaning pigs by increasing the concentration of α-tocopherol in the blood of weaning pigs when 0.02% vitamin E was supplemented. However, there was no significant difference in either the immune response or nutrient digestibility.

CONCLUSION

Inclusion of 0.1% β-Glucan with 0.02% vitamin E in a weaning pig's diet were beneficial to the growth performance of weaning pigs by improving intestinal microbiota and reducing the incidence of diarrhea.

The effects of dietary supplementation with mushroom or selenium enriched mushroom powders on the growth performance and intestinal health of post-weaned pigs

BACKGROUND

There is an urgent need to identify natural bioactive compounds that can enhance gastrointestinal health and promote pig growth performance in the absence of pharmacological levels of zinc oxide (ZnO). The objectives of this study were to: 1) compare the effects of mushroom powder supplemented with inorganic selenium (inSeMP) to mushroom powder enriched with organic selenium (orgSeMP) to pharmacological levels of ZnO on growth performance and faecal scores (FS) for the first 21 d post-weaning (Period 1); and 2) compare the molecular and microbial effects of inSeMP and orgSeMP in these pigs on d 39 post-weaning (Period 2).

METHODS

In Period 1, pigs (3 pigs/pen; 8 pens/treatment) were assigned to: (1) basal diet (control); (2) basal diet + zinc oxide (ZnO) (3100 mg/kg d 1-14, 1550 mg/kg d 15-21); (3) basal diet + mushroom powder supplemented with inorganic selenium (inSeMP) containing selenium (selenite) content of 0.3 mg/kg feed; (4) basal diet + mushroom powder enriched with organic selenium (orgSeMP) containing selenium (selenocysteine) content of 0.3 mg/kg feed. Mushroom powders were included at 6.5 g/kg of feed.

RESULTS

In Period 1, there was no effect of diets on average daily gain (ADG) and gain:feed (G:F) ratio (P > 0.05). The orgSeMP supplemented pigs had a lower average daily feed intake (ADFI) compared to all other groups (P < 0.05). The ZnO supplemented pigs had reduced FS compared to the basal and mushroom group, while the orgSeMP supplemented pigs had lower FS compared to the basal group during the 21 d experimental period (P < 0.05). In Period 2, there was no effect of diets on ADFI, ADG and G:F ratio (P > 0.05). The orgSeMP supplementation increased the caecal abundance of bacterial members of the Firmicutes and Bacteroidetes phylum, including Lactobacillus, Agathobacter, Roseburia, and Prevotella and decreased the abundance of Sporobacter compared to the basal group, while inSeMP increased the caecal abundance of Prevotella and decreased the caecal abundance of Sporobacter compared to the basal group (P < 0.05). Dietary supplementation with inSeMP increased expression of TLR4 and anti-inflammatory cytokine gene IL10 and decreased nutrient transporter gene FABP2 compared to the orgSeMP group (P < 0.05).

CONCLUSION

OrgSeMP is a novel and sustainable way to incorporate selenium and β-glucans into the diet of weaned pigs whilst improving FS and modulating the caecal microbiota.

Systematic review of animal-based indicators to measure thermal, social, and immune-related stress in pigs

The intense nature of pig production has increased the animals’ exposure to stressful conditions, which may be detrimental to their welfare and productivity. Some of the most common sources of stress in pigs are extreme thermal conditions (thermal stress), density and mixing during housing (social stress), or exposure to pathogens and other microorganisms that may challenge their immune system (immune-related stress). The stress response can be monitored based on the animals’ coping mechanisms, as a result of specific environmental, social, and health conditions. These animal-based indicators may support decision making to maintain animal welfare and productivity. The present study aimed to systematically review animal-based indicators of social, thermal, and immune-related stresses in farmed pigs, and the methods used to monitor them. Peer-reviewed scientific literature related to pig production was collected using three online search engines: ScienceDirect, Scopus, and PubMed. The manuscripts selected were grouped based on the indicators measured during the study. According to our results, body temperature measured with a rectal thermometer was the most commonly utilized method for the evaluation of thermal stress in pigs (87.62%), as described in 144 studies. Of the 197 studies that evaluated social stress, aggressive behavior was the most frequently-used indicator (81.81%). Of the 535 publications examined regarding immune-related stress, cytokine concentration in blood samples was the most widely used indicator (80.1%). Information about the methods used to measure animal-based indicators is discussed in terms of validity, reliability, and feasibility. Additionally, the introduction and wide spreading of alternative, less invasive methods with which to measure animal-based indicators, such as cortisol in saliva, skin temperature and respiratory rate via infrared thermography, and various animal welfare threats via vocalization analysis are highlighted. The information reviewed was used to discuss the feasible and most reliable methods with which to monitor the impact of relevant stressors commonly presented by intense production systems on the welfare of farmed pigs.

The effects of mushroom powder and vitamin D2 -enriched mushroom powder supplementation on the growth performance and health of newly weaned pigs

A complete randomised block design experiment was conducted to examine the effects of mushroom powder (MP) and vitamin D₂ -enriched mushroom powder (MPD₂ ) on growth performance, faecal scores, coefficient of apparent total tract digestibility (CATTD) of nutrients and selected microflora in weaned pigs up to day 35 post-weaning. One hundred and ninety-two weaned pigs (7.8kg [SD 1.08kg]) were blocked according to live weight, sex and litter of origin and randomly assigned to the following: (T1) control diet; (T2) control diet +MP; (T3) control diet + MPD₂ ; and (T4) control diet +zinc oxide (ZnO) (n = 12 replicates/treatment). Mushroom powders were included at 2 g/kg of feed achieving a β-glucan content of 200ppm. ZnO was included at 3100 mg/kg feed and halved to 1550 mg/kg after 21 days. Vitamin D content was enhanced in MPD₂ using synthetic UVB exposure to obtain a vitamin D₂ level of 100 µg/kg of feed. Faecal samples were collected on day 14 for microbial and nutrient digestibility analysis. There was no difference (p > 0.05) in ADG, G:F, faecal scores, microbial populations and CATTD of nutrients in pigs supplemented with MP or MPD₂ compared with the control diet. The supplementation of MP and MPD₂ caused a reduction (p < 0.05) in feed intake compared with the control and ZnO diet throughout the 35-day experimental period. ZnO supplementation increased ADG and ADFI (p < 0.05) during the first period (D0-21) compared with pigs offered MP and MPD₂ . In conclusion, MP and MPD₂ supplementation resulted in similar ADG, G:F, faecal scores compared with the control but were not comparable to ZnO, mainly due to a reduction in feed intake.

The anti-inflammatory effects of low- and high-molecular-weight beta-glucans from Agrobacterium sp. ZX09 in LPS-induced weaned piglets

The physicochemical characteristics of beta-glucans determine the immune responses of the intestines and whole body. It is hypothesized that glucans with different molecular weights have diverse modes of action on LPS-mediated immune activity. This study aimed to verify the immune-modulatory effects of two types of beta-glucans in LPS-induced weaned piglets. The results indicated that dietary beta-glucan supplementation could prevent losses in body weight gain caused by LPS challenge. Supplementation with different molecular weights of beta-glucans decreased the production of IL-1β and TNF-α and increased IL-10 production, which is likely associated with key factors such as TLR4 and NF-κB. High-molecular-weight beta-glucans seemed to have a strong functional capacity to modulate the innate immune response through the Dectin-1 receptor. Therefore, the results indicate that supplementing piglets with Agrobacterium sp. ZX09 beta-glucans inhibits LPS-mediated depression in the growth performance and plays a protective role during LPS challenge possibly via the Dectin-1 receptor and the TLR4/NF-κB pathway. The results reveal the potential therapeutic activity of purified Agrobacterium sp. ZX09 beta-glucan following experimental LPS infusion.

Dietary supplementation with hydrolyzed yeast and its effect on the performance, intestinal microbiota, and immune response of weaned piglets

The objective of this study was to evaluate the effects of autolyzed yeast on performance, cecal microbiota, and leukogram of weaned piglets. A total of 96 piglets of commercial line weaned at 21-day-old were used. The experimental design was a randomized block design with four treatments (diets containing 0.0%, 0.3%, 0.6%, and 0.9% autolyzed yeast), eight replicates, and three animals per pen in order to evaluate daily weight gain, daily feed intake, and feed conversion in periods of 0 to 15, 0 to 26, and 0 to 36 days. Quadratic effects of autolyzed yeast inclusion were observed on the feed conversion from 0 to 15 days, on daily weight gain from 0 to 15 days, 0 to 26 days and, 0 to 36 days, indicating an autolyzed yeast optimal inclusion level between 0.4% and 0.5%. No effect from autolyzed yeast addition was observed on piglet daily feed intake, cecal microbiota, and leukogram; however, i.m. application of E. coli lipopolysaccharide reduced the values ​​of total leukocytes and their fractions (neutrophils, eosinophils, lymphocytes, monocytes, and rods). Therefore, autolyzed yeast when provided at levels between 0.4% and 0.5% improved weaned piglets' performance.

Effects of hydrolyzed yeast supplementation on growth performance, immunity, antioxidant capacity, and microbial shedding in weaning pigs

Background and Aim

Weaning pigs normally suffer from many stressors which have impaired growth performance and immunity. Hydrolyzed yeast has been proposed as an alternative feed additive. The aim of this study was to investigate the effects of various levels of hydrolyzed yeast (HY) supplementation in the feed of weaning pigs on growth performance, diarrhea incidence, immunity, antioxidant capacity, and microbial populations.

Materials and Methods

A total of 144 crossbred weaning pigs (Duroc × Landrace × Large White) with a mean body weight (BW) of 7.46 kg were randomly assigned to one of four treatments during a 5-week feeding trial. Treatments consisted of a basal diet without HY inclusion (control), or the basal diet supplemented with HY at 0.5, 1.0, and 1.5 g/kg of diet, respectively.

Results

Piglets fed with 1.0 or 1.5 g/kg HY presented significantly increased BW (p=0.009) and decreased incidence of diarrhea (p=0.001). The final BW (p=0.012), average daily gain (p=0.094), and average daily feed intake (p=0.091) showed a linear improvement with the level of HY inclusion. However, the gain-to-feed ratio was unaffected by dietary treatments. Linear responses to the HY supplementation levels were also observed for blood urea nitrogen (p=0.030), total protein (p=0.017), lymphocyte percentage (p=0.064), catalase activity (p=0.089), malondialdehyde (MDA) level (p=0.001), Salmonella spp. (p=0.024), Escherichia coli (p=0.021), and Lactobacillus spp. (p=0.048). Dietary inclusion of HY at 1.0 and 1.5 g/kg resulted in increased immunoglobulin A and G secretions (p=0.042 and p=0.022, respectively) and decreased MDA concentration (p<0.01) and Salmonella spp. (p=0.026) and E. coli (p=0.050).

Conclusion

It was concluded that HY inclusion at 1.0 and 1.5 g/kg in the diet of weaning pigs improve BW, immunoglobulin secretion, and antioxidant enzyme activity, whereas it lowers diarrhea occurrence, lipid peroxidation, and pathogenic bacteria in weaning pigs.

Innate Immunomodulation in Food Animals: Evidence for Trained Immunity?

Antimicrobial resistance (AMR) is a significant problem in health care, animal health, and food safety. To limit AMR, there is a need for alternatives to antibiotics to enhance disease resistance and support judicious antibiotic usage in animals and humans. Immunomodulation is a promising strategy to enhance disease resistance without antibiotics in food animals. One rapidly evolving field of immunomodulation is innate memory in which innate immune cells undergo epigenetic changes of chromatin remodeling and metabolic reprogramming upon a priming event that results in either enhanced or suppressed responsiveness to secondary stimuli (training or tolerance, respectively). Exposure to live agents such as bacille Calmette-Guerin (BCG) or microbe-derived products such as LPS or yeast cell wall ß-glucans can reprogram or "train" the innate immune system. Over the last decade, significant advancements increased our understanding of innate training in humans and rodent models, and strategies are being developed to specifically target or regulate innate memory. In veterinary species, the concept of enhancing the innate immune system is not new; however, there are few available studies which have purposefully investigated innate training as it has been defined in human literature. The development of targeted approaches to engage innate training in food animals, with the practical goal of enhancing the capacity to limit disease without the use of antibiotics, is an area which deserves attention. In this review, we provide an overview of innate immunomodulation and memory, and the mechanisms which regulate this long-term functional reprogramming in other animals (e.g., humans, rodents). We focus on studies describing innate training, or similar phenomenon (often referred to as heterologous or non-specific protection), in cattle, sheep, goats, swine, poultry, and fish species; and discuss the potential benefits and shortcomings of engaging innate training for enhancing disease resistance.

The Gut-Lung Axis in Health and Respiratory Diseases: A Place for Inter-Organ and Inter-Kingdom Crosstalks

The gut and lungs are anatomically distinct, but potential anatomic communications and complex pathways involving their respective microbiota have reinforced the existence of a gut-lung axis (GLA). Compared to the better-studied gut microbiota, the lung microbiota, only considered in recent years, represents a more discreet part of the whole microbiota associated to human hosts. While the vast majority of studies focused on the bacterial component of the microbiota in healthy and pathological conditions, recent works have highlighted the contribution of fungal and viral kingdoms at both digestive and respiratory levels. Moreover, growing evidence indicates the key role of inter-kingdom crosstalks in maintaining host homeostasis and in disease evolution. In fact, the recently emerged GLA concept involves host-microbe as well as microbe-microbe interactions, based both on localized and long-reaching effects. GLA can shape immune responses and interfere with the course of respiratory diseases. In this review, we aim to analyze how the lung and gut microbiota influence each other and may impact on respiratory diseases. Due to the limited knowledge on the human virobiota, we focused on gut and lung bacteriobiota and mycobiota, with a specific attention on inter-kingdom microbial crosstalks which are able to shape local or long-reached host responses within the GLA.

Effect of dietary supplementation with brewer's yeast hydrolysate on growth performance, faecal microbial counts, diarrhoea score, blood profile, rectal temperature in weanling pigs challenged with lipopolysaccharide

The objective of this study was to determine the effects of brewer's yeast hydrolysate (BYH) supplementation on growth performance, blood profile, diarrhoea score, faecal microbial and rectal temperature in lipopolysaccharide (LPS) challenged in weanling pigs. A total of 40 cross-bred weanling pigs [(Yorkshire × Landrace) × Duroc] with an average body weight of 8.15 ± 0.87 kg were used in a 6 weeks experiment. Pigs were randomly allotted to the following four dietary treatments (five pigs/two replicate/treatment) according to their initial body weight and gender. Treatments were as follows: CON, basal diet + Saline injection; NC, basal diet + LPS challenge; PC1, basal diet + 1.0% BYH + saline injection; and PC2, basal diet + 1.0% BYH + LPS challenge. Our results demonstrated pig fed diets with BYH had higher (p < .05) average daily feed intake (ADFI) during week 2-4 as well as gain:feed (G:F) during the whole experimental period than pigs fed diets without BYH. At the end of experiment, faecal Escherichia coli counts in pigs with an LPS injection tended to increase (p = .08). Meanwhile, the rectal temperature concentration of IgM and lymphocyte percentage in pigs with an LPS injection increase (p = .05) at 6 and 12 hr. In conclusion, the supplementation of 1.0% BYH can improve ADFI and G:F, as well as may reduce the diarrhoea in weanling pigs.

Purified β-glucans of Different Molecular Weights Enhance Growth Performance of LPS-challenged Piglets via Improved Gut Barrier Function and Microbiota

Simple Summary

Beta-glucan is currently under consideration as an alternative to in-feed antibiotics for the sustainable pig production industry in China. Modulating intestinal function by β-glucan treatment in young pigs is one potential way of decreasing disease susceptibility and presumably increasing growth performance. In the present study, as a newly developed commercial product, β-glucans have proved to modulate gut function, and have improved growth performance in lipopolysaccharide (LPS)-challenged piglets. The present study aimed to determine the mechanisms involved inβ-glucan of low and high molecular weight mediated growth alterations in weaned piglets. The results confirmed that β-glucans isolated from Agrobacterium sp. ZX09 could improve growth performance in weaned piglets and they showed intestinal modulatory properties via different mechanisms in regulating the mucosal barrier function and microbial populations between two different molecular weight β-glucans.

Abstract

This study investigated β-glucan derived from Agrobacterium sp. ZX09 with high (2000 kDa) and low (300 kDa) molecular weight (MW) to compare their effects on growth performance and gut function in LPS-induced weaned piglets. Changes in jejunal morphology, mucosal barrier function, microbial populations, and fermentation in the piglets were determined. Data showed that β-glucan prevented body weight loss in LPS challenged piglets. Supplementation with both β-glucan fractions improved jejunal morphology. Compared to low MW, β-glucan of high MW generally up-regulated transcripts of ZO-1, MUC1, and MUC2 in jejunal mucosa to a lesser extent. Mucosal D-lactate, diamine oxidase, and anti-oxidation index were effectively resumed in β-glucan treatment. Both β-glucan diets provoked the emergence of a balanced microbiota and a richer concentration of volatile fatty acids in the colon. The richest community of bifidobacterium and concentration of butyrate emerged after feeding β-glucan with high MW. Results suggested that the effect of Agrobacterium sp. ZX09 β-glucans on the gut-modulatory function is largely linked to their MW. Low MW β-glucan mainly improved the mucosal barrier function in the jejunum, while high MW β-glucan had profound effects on the microbial community and fermentation in the hindgut of piglets.

Beta-glucan from Agrobacterium sp. ZX09 improves growth performance and intestinal function in weaned piglets

Beta-glucan is currently under consideration as an alternative to in-feed antibiotics. The aim of the study was to investigate Agrobacterium sp. ZX09 beta-glucan on intestinal morphology, cytokine concentration, mucin expression and microbial populations of weaning piglets. Pigs were randomly assigned to one of five dietary treatments supplemented with 0, 25, 50, 100 and 200 mg/kg beta-glucan. Data showed an increase in ADG at the 100 mg/kg group (p = .03). A significant increase in villus height and reduction in crypt depth were fund in ileal tissue at the 100 mg/kg inclusion level (p < .05). Dietary supplementation of 100 mg/kg beta-glucan enhanced IL-10 concentration (p = .04) and gene expression of MUC1 and MUC2 (p < .05) in the jejunum. Dietary supplementation of 100 mg/kg beta-glucan provoked the up-regulation of Lactobacillus counts and down-regulation of Escherichia coli counts in the caecum (p = .05). Data suggested that improved growth performance in response to beta-glucan supplementation at 100 mg/kg in weaned piglets may be explained by the improved intestinal function.

Dietary β-glucan supplementation improves growth performance, carcass traits and meat quality of finishing pigs

This experiment was conducted to investigate growth performance, carcass traits and meat quality of finishing pigs with dietary β-glucan supplementation. A total of 96 healthy pigs (Duroc × Landrace × Yorkshire; initial average BW = 25 kg) were randomly allocated into 4 dietary treatments with 6 replicates per treatment and 4 pigs per replicate. The control group was fed a basal diet, and the experimental diets were supplemented with 50, 100 and 200 mg/kg Agrobacterium sp. ZX09 β-glucan, respectively. The experiment lasted 103 d. The basal diet supplemented with 100 mg/kg β-glucan significantly increased average daily gain and feed conversion ratio, probably due to the improved digestibility of dry matter, gross energy and crude protein (P < 0.05). Beta-glucan supplementation from 100 to 200 mg/kg of diet significantly increased carcass length (P < 0.05). The basal diet supplemented with 100 mg/kg β-glucan supplementation also significantly (P < 0.05) increased muscle pH, reduced drip losses and increased a^∗ values. The basal diet supplemented with 100 mg/kg β-glucan increased the content of intramuscular fat and changed the proportion of saturated fatty acid and unsaturated fatty acid, thereby improved the flavor of meat. In conclusion, the basal diet supplemented with 100 mg/kg Agrobacterium sp. ZX09 β-glucan improves growth performance, nutrient digestibility, carcass length, and pork quality of finishing pigs.

Oat beta-glucan as a dietary supplement for dogs

The aim of this study was to evaluate the effects of oat beta-glucan supplementation on metabolic, physiological, immunological and nutritional variables in adult dogs. Fourteen dogs were fed a control diet or a diet supplemented with 1% beta-glucan during 71 days. Serum concentrations of glucose, total cholesterol and lipoprotein fractions, as well as plasma concentrations of peptide YY and ghrelin, were determined. In addition, coefficient of total tract apparent macronutrient digestibility (CTTAD), food intake and fecal output, score, and pH were evaluated. For evaluation of immunological variables, serum concentrations of interleukin-4 and interferon gamma were determined on days 0, 57 and 71, which corresponded to blood collection prior to beta-glucan supplementation, and at 7 and 14 days post first and second dose of vaccination (Pneumodog^®, Merial, Campinas, Brazil), respectively. Animals fed the supplemented diet showed (P<0.05) lower serum concentrations of total cholesterol and low and very low density lipoproteins, lower coefficients of total tract apparent digestibility of dry matter, organic matter, mineral matter and ether extract, higher fecal output and lower fecal consistency, as well as a tendency (P = 0.07) of decreasing the coefficient of total tract apparent digestibility of crude protein. Moreover, the supplemented diet resulted in lower number of red blood cells, hematocrit percentage and hemoglobin concentration 21 days post-vaccination as well as lower serum concentration of interleukin-4 seven days post-vaccination (P<0.05). It is concluded that oat beta-glucan extract can be used as a dietary supplement for dogs at a dose of 10 g/kg of food, being effective in reducing blood concentrations of total cholesterol, LDL-c and VLDL-c as well as CTTAD of nutrients, demonstrating a potential to be used in the feeding of obese animals. In addition, by reducing the predominance of a Th2 response, oat beta-glucan can positively modulate the vaccine response of animals.

Growth performance, nutrient digestibility, and selected fecal microbiota are improved by β-glucan supplementation in weaner pigs

This study was conducted to evaluate the effects of dietary β-glucan supplementation on growth performance, nutrient digestibility, blood profiles, and fecal characteristics in weaner pigs. A total of 140 weaner pigs [(Yorkshire × Landrace) × Duroc] with an average body weight of 6.37±1.14 kg were allotted to one of the following dietary treatments: 1) negative control (NC, basal diet); 2) positive control (PC, basal diet supplemented with 39 ppm Tiamulin); 3) basal diet supplemented with 0.1% β-glucan (G1); 4) basal diet supplemented with 0.2% β-glucan (G2). During days 22 to 42 and 1 to 42, pigs offered PC and G2 diets grew faster than those offered NC diet (P<0.05). Additionally, during the same periods, pigs fed G2 and PC diets exhibited improved gain:feed ratio compared to pigs receiving NC and G1 diets (P<0.05). Pigs fed G2 diet exhibited higher coefficient of total tract apparent digestibility of dry matter than those fed NC diet (P<0.05). There were no differences on blood profiles, fecal scores, fecal moisture, and fecal pH (P>0.05). Fecal lactic acid bacteria counts in G2 treatment were higher compared with PC and NC treatments (P<0.05). Coliform bacteria concentrations were decreased in pigs fed PC and G2 diets compared with those fed NC diet (P<0.05). In conclusion, the results of the current study indicate that dietary supplementation of 0.2% β-glucan can improve growth performance and dry matter digestibility, increase fecal lactic acid bacteria concentration but decrease fecal coliform bacteria concentration in weaner pigs.

In vitro bioassessment of the immunomodulatory activity of Saccharomyces cerevisiae components using bovine macrophages and Mycobacterium avium ssp. paratuberculosis

The yeast Saccharomyces cerevisiae and its components are used for the prevention and treatment of enteric disease in different species; therefore, they may also be useful for preventing Johne's disease, a chronic inflammatory bowel disease of ruminants caused by Mycobacterium avium ssp. paratuberculosis (MAP). The objective of this study was to identify potential immunomodulatory S. cerevisiae components using a bovine macrophage cell line (BOMAC). The BOMAC phagocytic activity, reactive oxygen species production, and immune-related gene (IL6, IL10, IL12p40, IL13, IL23), transforming growth factor β, ARG1, CASP1, and inducible nitric oxide synthase expression were investigated when BOMAC were cocultured with cell wall components from 4 different strains (A, B, C, and D) and 2 forms of dead yeast from strain A. The BOMAC phagocytosis of mCherry-labeled MAP was concentration-dependently attenuated when BOMAC were cocultured with yeast components for 6 h. Each yeast derivative also induced a concentration-dependent increase in BOMAC reactive oxygen species production after a 6-h exposure. In addition, BOMAC mRNA expression of the immune-related genes was investigated after 6 and 24 h of exposure to yeast components. All yeast components were found to regulate the immunomodulatory genes of BOMAC; however, the response varied among components and over time. The in vitro bioassessment studies reported here suggest that dead yeast and its cell wall components may be useful for modulating macrophage function before or during MAP infection.

The Mycobiome: A Neglected Component in the Microbiota-Gut-Brain Axis

In recent years, the gut microbiota has been considered as a full-fledged actor of the gut-brain axis, making it possible to take a new step in understanding the pathophysiology of both neurological and psychiatric diseases. However, most of the studies have been devoted to gut bacterial microbiota, forgetting the non-negligible fungal flora. In this review, we expose how the role of the fungal component in the microbiota-gut-brain axis is legitimate, through its interactions with both the host, especially with the immune system, and the gut bacteria. We also discuss published data that already attest to a role of the mycobiome in the microbiota-gut-brain axis, and the impact of fungi on clinical and therapeutic research.

The Fungal Mycobiome and Its Interaction with Gut Bacteria in the Host

The advent of sequencing technology has endowed us with the capacity to study microbes constituting the human commensal community that were previously non-culturable. Much of the initial works have concentrated on the bacterial flora constituting the gut microbiome, since specimens are readily accessible in health and disease. Less, however, is understood of the “silent population”—the fungal species, also known as the mycobiome. Living in symbiosis with bacteria as commensals in our body, it is perceivable that the mycobiome exerts an inadvertent influence on the microbiome. We review here the recent knowledge gained from study of the interaction between the mycobiome and microbiome in health and disease susceptibility, immunity, and consequences from antimicrobial treatment.

Effects of Saccharomyces cerevisiae cell wall extract and poplar propolis ethanol extract supplementation on growth performance, digestibility, blood profile, fecal microbiota and fecal noxious gas emissions in growing pigs

A total of 105 growing pigs (24.91 ± 1.06 kg) were used in a 6-week trial to investigate the effects of including Saccharomyces cerevisiae cell wall extract and poplar propolis ethanol extract (SPE) in the diet on growth performance, digestibility, blood profiles, fecal microbiota and fecal noxious gas emissions. Pigs were randomly allocated to one of three dietary treatments (seven pens/treatment, five pigs/pen) according to initial body weight and sex (two gilts and three barrows). Treatments consisted of a corn soybean meal basal diet supplemented with 0, 0.05 or 0.10% SPE. There was a significant linear improvement (P < 0.05) in average daily gain, gain/feed, the apparent total tract digestibility of dry matter, nitrogen, and gross energy, blood lymphocyte percentage, immunoglobulin G concentration, fecal Escherichia coli and Lactobacillus counts as well as fecal NH3 and H2 S emissions associated with the inclusion of SPE in the diet. Average daily feed intake, red blood cells and white blood cells concentration were not significantly (P > 0.05) affected by SPE supplementation in the diets. In conclusion, results indicate that dietary SPE supplementation can improve growth performance, digestibility and fecal microbiota, and decrease fecal gas emissions in growing pigs.