The Autosow raised miniature swine as a model for assessing the effects of dietary soy trypsin inhibitor

Comparison of maternal and neonatal gut microbial community and function in a porcine model

Our knowledge of the difference in maternal and neonatal gut microbiota composition is not fully understood. Using the Bama miniature pig model, the bacterial community in the feces from sows and piglets was analyzed on an IonS5TMXL platform targeting the single-end reads strategy. Results revealed that the maternal and neonatal bacteria profile in the pig model was distinct. Compared with the piglets, sows had higher proportions of bacteria in Spirochetes, Clostridiales, and Spirochaetales (p < 0.10) and had a lower abundance of bacteria in Tyzzerella (p < 0.05) and Alistipes (p < 0.10). Meanwhile, the proportions of bacteria in Oscillibacter and the index of Chao1, Shannon, and observed_species increased in the sows compared with those in the piglets (p < 0.05). Moreover, the abundance of bacteria associated with the human disease was higher (p < 0.05) and the population of bacteria associated with cellular processes was lower (p < 0.05) in the piglets compared with those in the sows. Collectively, the diversity and beneficial bacteria populations in the sow fecal microbiota exhibit more than those in the piglets. This study indicates that maternal fecal microbiota may be a beneficial source of transplanted bacteria to promote healthy function in neonates.

Gut microbiota absence and transplantation affect growth and intestinal functions: An investigation in a germ-free pig model

This study was conducted to investigate host–microbiota interactions and explore the effects of maternal gut microbiota transplantation on the growth and intestinal functions of newborns in a germ-free (GF) pig model. Twelve hysterectomy-derived GF Bama piglets were reared in 6 sterile isolators. Among them, 6 were considered as the GF group, and the other 6 were orally inoculated with healthy sow fecal suspension as fecal microbiota transplanted (FMT) group. Another 6 piglets from natural birth were regarded as the conventional (CV) group. The GF and FMT groups were hand-fed with Co60-γ-irradiated sterile milk powder, while the CV group was reared by lactating Bama sows. All groups were fed for 21 days. Then, all piglets and then were switched to sterile feed for another 21 days. Results showed that the growth performance, nutrient digestibility, and concentrations of short-chain fatty acids in the GF group decreased (P < 0.05). Meanwhile, the serum urea nitrogen concentration and digesta pH values in the GF group increased compared with those in the FMT and CV groups (P < 0.05). Compared with the CV group, the GF group demonstrated upregulation in the mRNA expression levels of intestinal barrier function-related genes in the small intestine (P < 0.05). In addition, the mRNA abundances of intestinal development and absorption-related genes in the small intestine and colon were higher in the GF group than in the CV and FMT groups (P < 0.05). The FMT group exhibited greater growth performance, lipase activity, and nutrient digestibility (P < 0.05), higher mRNA expression levels of intestinal development and barrier-related genes in the small intestine (P < 0.05), and lower mRNA abundances of pro-inflammatory factor in the colon and jejunum (P < 0.05) than the CV group. In conclusion, the absence of gut microbes impaired the growth and nutrient digestibility, and healthy sow gut microbiota transplantation increased the growth and nutrient digestibility and improved the intestinal development and barrier function of newborn piglets, indicating the importance of intestinal microbes for intestinal development and functions.

Spatial heterogeneity of bacterial colonization across different gut segments following inter-species microbiota transplantation

BACKGROUND

The microbiota presents a compartmentalized distribution across different gut segments. Hence, the exogenous microbiota from a particular gut segment might only invade its homologous gut location during microbiota transplantation. Feces as the excreted residue contain most of the large-intestinal microbes but lack small-intestinal microbes. We speculated that whole-intestinal microbiota transplantation (WIMT), comprising jejunal, ileal, cecal, and colonic microbiota, would be more effective for reshaping the entire intestinal microbiota than conventional fecal microbiota transplantation fecal microbiota transplantation (FMT).

RESULTS

We modeled the compartmentalized colonization of the gut microbiota via transplanting the microbiota from jejunum, ileum, cecum, and colon, respectively, into the germ-free mice. Transplanting jejunal or ileal microbiota induced more exogenous microbes' colonization in the small intestine (SI) of germ-free mice rather than the large intestine (LI), primarily containing Proteobacteria, Lactobacillaceae, and Cyanobacteria. Conversely, more saccharolytic anaerobes from exogenous cecal or colonic microbiota, such as Bacteroidetes, Prevotellaceae, Lachnospiraceae, and Ruminococcaceae, established in the LI of germ-free mice that received corresponding intestinal segmented microbiota transplantation. Consistent compartmentalized colonization patterns of microbial functions in the intestine of germ-free mice were also observed. Genes related to nucleotide metabolism, genetic information processing, and replication and repair were primarily enriched in small-intestinal communities, whereas genes associated with the metabolism of essential nutrients such as carbohydrates, amino acids, cofactors, and vitamins were mainly enriched in large-intestinal communities of germ-free mice. Subsequently, we compared the difference in reshaping the community structure of germ-free mice between FMT and WIMT. FMT mainly transferred LI-derived microorganisms and gene functions into the recipient intestine with sparse SI-derived microbes successfully transplanted. However, WIMT introduced more SI-derived microbes and associated microbial functions to the recipient intestine than FMT. Besides, WIMT also improved intestinal morphological development as well as reduced systematic inflammation responses of recipients compared with FMT.

CONCLUSIONS

Segmented exogenous microbiota transplantation proved the spatial heterogeneity of bacterial colonization along the gastrointestinal tract, i.e., the microbiota from one specific location selectively colonizes its homologous gut region. Given the lack of exogenous small-intestinal microbes during FMT, WIMT may be a promising alternative for conventional FMT to reconstitute the microbiota across the entire intestinal tract. Video Abstract.

The Effect of Dietary Mushroom Agaricus bisporus on Intestinal Microbiota Composition and Host Immunological Function

A study was designed to determine the potential prebiotic effect of dietary mushrooms on the host immune response, and intestinal microbiota composition and function. Thirty-one six-week-old pigs were fed a pig grower diet alone or supplemented with either three or six servings of freeze-dried white button (WB)-mushrooms for six weeks. Host immune response was evaluated in peripheral blood mononuclear cells (PBMC), and alveolar macrophages (AM) after stimulation with Salmonella typhymurium-Lipopolysaccharide (LPS). Isolated DNA from fecal and proximal colon contents were used for 16S rDNA taxonomic analysis and linear discriminant analysis effect size (LEfSe) to determine bacterial abundance and metabolic function. Pigs gained weight with no difference in body composition or intestinal permeability. Feeding mushrooms reduced LPS-induced IL-1β gene expression in AM (P < 0.05) with no change in LPS-stimulated PBMC or the intestinal mucosa transcriptome. LEfSe indicated increases in Lachnospiraceae, Ruminococcaceae within the order Clostridiales with a shift in bacterial carbohydrate metabolism and biosynthesis of secondary metabolites in the mushroom-fed pigs. These results suggested that feeding WB mushrooms significantly reduced the LPS-induced inflammatory response in AM and positively modulated the host microbiota metabolism by increasing the abundance of Clostridiales taxa that are associated with improved intestinal health.

Standardized Preparation for Fecal Microbiota Transplantation in Pigs

The intestine of pigs harbors a mass of microorganisms which are essential for intestinal homeostasis and host health. Intestinal microbial disorders induce enteric inflammation and metabolic dysfunction, thereby causing adverse effects on the growth and health of pigs. In the human medicine, fecal microbiota transplantation (FMT), which engrafts the fecal microbiota from a healthy donor into a patient recipient, has shown efficacy in intestinal microbiota restoration. In addition, it has been used widely in therapy for human gastrointestinal diseases, including Clostridium difficile infection, inflammatory bowel diseases, and irritable bowel syndrome. Given that pigs share many similarities with humans, in terms of anatomy, nutritional physiology, and intestinal microbial compositions, FMT may also be used to restore the normal intestinal microbiota of pigs. However, feasible procedures for performing FMT in pigs remains unclear. Here, we summarize a standardized preparation for FMT in pigs by combining the standard methodology for human FMT with pig production. The key issues include the donor selection, fecal material preparation, fecal material transfer, stool bank establishment, and the safety for porcine FMT. Optimal donors should be selected to ensure the efficacy of porcine FMT and reduce the risks of transmitting infectious diseases to recipients during FMT. Preparing for fresh fecal material is highly recommended. Alternatively, frozen fecal suspension can also be prepared as an optimal choice because it is convenient and has similar efficacy. Oral administration of fecal suspension could be an optimal method for porcine fecal material transfer. Furthermore, the dilution ratio of fecal materials and the frequency of fecal material transfer could be adjusted according to practical situations in the pig industry. To meet the potential large-scale requirement in the pig industry, it is important to establish a stool bank to make porcine FMT readily available. Future studies should also focus on providing more robust safety data on FMT to improve the safety and tolerability of the recipient pigs. This standardized preparation for porcine FMT can facilitate the development of microbial targeted therapies and improve the intestinal health of pigs.

Integrative Physiology: At the Crossroads of Nutrition, Microbiota, Animal Physiology, and Human Health

Nutrition is paramount in shaping all aspects of animal biology. In addition, the influence of the intestinal microbiota on physiology is now widely recognized. Given that diet also shapes the intestinal microbiota, this raises the question of how the nutritional environment and microbial assemblages together influence animal physiology. This research field constitutes a new frontier in the field of organismal biology that needs to be addressed. Here we review recent studies using animal models and humans and propose an integrative framework within which to define the study of the diet-physiology-microbiota systems and ultimately link it to human health. Nutritional Geometry sits centrally in the proposed framework and offers means to define diet compositions that are optimal for individuals and populations.

Gradual Changes of Gut Microbiota in Weaned Miniature Piglets

Colonization of gut microbiota in mammals during the early life is vital to host health. The miniature piglet has recently been considered as an optimal infant model. However, less is known about the development of gut microbiota in miniature piglets. Here, this study was conducted to explore how the gut microbiota develops in weaned Congjiang miniature piglets. In contrast to the relatively stabilized gut fungal community, gut bacterial community showed a marked drop in alpha diversity, accompanied by significant alterations in taxonomic compositions. The relative abundances of 24 bacterial genera significantly declined, whereas the relative abundances of 7 bacterial genera (Fibrobacter, Collinsella, Roseburia, Prevotella, Dorea, Howardella, and Blautia) significantly increased with the age of weaned piglets. Fungal taxonomic analysis showed that the relative abundances of two genera (Kazachstania and Aureobasidium) significantly decreased, whereas the relative abundances of four genera (Aspergillus, Cladosporium, Simplicillium, and Candida) significantly increased as the piglets aged. Kazachstania telluris was the signature species predominated in gut fungal communities of weaned miniature piglets. The functional maturation of the gut bacterial community was characterized by the significantly increased digestive system, glycan biosynthesis and metabolism, and vitamin B biosynthesis as the piglets aged. These findings suggest that marked gut microbial changes in Congjiang miniature piglets may contribute to understand the potential gut microbiota development of weaned infants.

Pretreatment of epithelial cells with live Streptococcus pneumoniae has no detectable effect on influenza A virus replication in vitro

Influenza A virus (IAV) and Streptococcus pneumoniae (pneumococcus) are two major upper respiratory tract pathogens responsible for exacerbated disease in coinfected individuals. Despite several studies showing increased susceptibility to secondary bacterial infections following IAV infection, information on the direct effect of S. pneumoniae on IAV in vitro is unknown. This is an important area of investigation as S. pneumoniae is a common commensal of the human upper respiratory tract, present as an important coinfecting pathogen with IAV infection. A recent study showed that S. pneumoniae enhances human metapneumovirus infection in polarized bronchial epithelial cells in vitro. The aim of the current study was to determine whether treatment of epithelial cells with S. pneumoniae affects IAV replication using a standard immunofluorescence assay (IFA). For this study we used four IAV permissive epithelial cell lines including two human-derived cell lines, 12 pneumococcal strains including recent human clinical isolates which represent different genetic backgrounds and serotypes, and six IAV strains of varying genetic nature and pathogenic potential including the pandemic 2009 H1N1 virus. Our results suggested that pretreatment of MDCK cells with 7.5×10⁶ colony-forming units (CFUs) of live S. pneumoniae resulted in gradual cell-death in a time-dependent manner (0.5 to 4 hr). But, pretreatment of cell lines with 7.5×10⁵ and lower CFUs of S. pneumoniae had no detectable effect on either the morphology of cells or on the IAV replication. However, unlike in epithelial cell lines, due to influence of secreted host factors the effect of pneumococci on IAV replication may be different during coinfections in vivo in the human upper respiratory tract, and in vitro with primary human polarized bronchial epithelial cells.

Safety assessment of probiotics for human use

The safety of probiotics is tied to their intended use, which includes consideration of potential vulnerability of the consumer or patient, dose and duration of consumption, and both the manner and frequency of administration. Unique to probiotics is that they are alive when administered, and unlike other food or drug ingredients, possess the potential for infectivity or in situ toxin production. Since numerous types of microbes are used as probiotics, safety is also intricately tied to the nature of the specific microbe being used. The presence of transferable antibiotic resistance genes, which comprises a theoretical risk of transfer to a less innocuous member of the gut microbial community, must also be considered. Genetic stability of the probiotic over time, deleterious metabolic activities, and the potential for pathogenicity or toxicogenicity must be assessed depending on the characteristics of the genus and species of the microbe being used. Immunological effects must be considered, especially in certain vulnerable populations, including infants with undeveloped immune function. A few reports about negative probiotic effects have surfaced, the significance of which would be better understood with more complete understanding of the mechanisms of probiotic interaction with the host and colonizing microbes. Use of readily available and low cost genomic sequencing technologies to assure the absence of genes of concern is advisable for candidate probiotic strains. The field of probiotic safety is characterized by the scarcity of studies specifically designed to assess safety contrasted with the long history of safe use of many of these microbes in foods.

Serum IgA-promoting effects induced by feed loads containing isolated deoxynivalenol (DON) in growing piglets

Deoxynivalenol (DON), a Fusarium toxin belonging to the trichothecene group, has been reported to produce a variety of adverse health effects in farm animals, such as inhibition of protein synthesis, reduction of feed intake, and alteration of the immune system. In pigs, the effects of increasing levels of chemically pure DON in a semisynthetic diet on performance, health, and serum immunglobulin A (IgA) levels were examined. A diet, without grain components and trichothecene free (8 main trichothecenes), with doses of 0, 300, 600, and 1200 microg pure DON/kg was fed to 34 female pigs for a period of 8 wk after weaning under standardized conditions. Body weight gain and biochemical and hematological values in the blood and serum, including concentrations of IgA, blood glucose, cortisol, and insulinlike growth factor 1 (IGF-1), were determined. Increasing levels of DON in the feed induced a significant depression of glucose levels. Cortisol and IGF-1 levels were not significantly affected but differed between groups at the end of the experiment. A significant increase of IgA concentration in the serum even at a dosage level of 600 microg DON/kg feed was observed. This is the first report demonstrating in vivo that limited dosages of DON are able to stimulate IgA levels in the serum of growing piglets.

Pathological evaluation, clinical chemistry and plasma cholecystokinin in neonatal and young miniature swine fed soy trypsin inhibitor from 1 to 39 weeks of age

The potential toxicity of dietary soy trypsin inhibitor (TI) was evaluated in neonatal miniature swine. From 1 to 6 weeks of age, two groups of male piglets were artificially reared in an Autosow and automatically fed either TI or control liquid diet. From 6 to 39 weeks of age, these two groups were fed either TI or control chow diet. A third group, sow control (SC), suckled from birth to 6 weeks of age, were also weaned to control chow from 6 to 39 weeks of age. Clinical chemistry and plasma cholecystokinin (CCK) determined at 6, 18, 30 and 39 weeks of age, and serum amylase activity with gross and histopathological analyses of major organs at 6 and 39 weeks of age are reported. TI had no effect on plasma CCK, serum amylase activity, or numerous clinical chemistry values. TI-fed piglets had a larger relative liver weight at 6 weeks of age. Relative pancreas weight decreased with age but was not affected by TI. Gross and histopathological analyses of major organs, except the spleen, were within normal limits. Increased incidence of extramedullary hematopoiesis was noted in the spleen of the TI group at 6 but not at 39 weeks of age. There was no consistent pattern in immunohistochemical foci for secretin, gastrin releasing polypeptide or CCK, and no change in DNA, RNA, mitotic index or nuclear density of pancreatic cells. At 6 weeks of age, TI increased pancreatic protein and amylase activity but not trypsin or chymotrypsin activity. None of the effects suggested that this dose of TI was toxic to either the neonatal or sexually mature miniature male swine.