FUT1 genetic variants impact protein glycosylation of porcine intestinal mucosa

Role of genetic factors in different swine breeds exhibiting varying levels of resistance/susceptibility to PRRSV

Porcine reproductive and respiratory syndrome (PRRS), caused by the PRRS virus (PRRSV), is an economically significant contagious disease. Traditional approaches based on vaccines or medicines were challenging to control PRRSV due to the diversity of viruses. Different breeds of pigs infected with PRRSV have been reported to have different immune responses. However, due to the complexity of interaction mechanism between host and PRRSV, the genetic mechanism leading to PRRSV susceptibility/resistance in various pig breeds is still unclear. Herein, the role of host genetic components in PRRSV susceptibility is systematically described, and the molecular mechanisms by which host genetic factors such as SNPs, cytokines, receptor molecules, intestinal flora, and non-coding RNAs regulate PRRSV susceptibility/resistance. Therefore, improving the resistance to disease of individual animals through disease-resistance breeding technology is of profound significance for uplifting the sustainable and healthy development of the pig industry.

The TGF-β ligand DBL-1 is a key player in a multifaceted probiotic protection against MRSA in C. elegans

Worldwide the increase in multi-resistant bacteria due to misuse of traditional antibiotics is a growing threat for our health. Finding alternatives to traditional antibiotics is thus timely. Probiotic bacteria have numerous beneficial effects and could offer safer alternatives to traditional antibiotics. Here, we use the nematode Caenorhabditis elegans (C. elegans) to screen a library of different lactobacilli to identify potential probiotic bacteria and characterize their mechanisms of action. We show that pretreatment with the Lactobacillus spp. Lb21 increases lifespan of C. elegans and results in resistance towards pathogenic methicillin-resistant Staphylococcus aureus (MRSA). Using genetic analysis, we find that Lb21-mediated MRSA resistance is dependent on the DBL-1 ligand of the TGF-β signaling pathway in C. elegans. This response is evolutionarily conserved as we find that Lb21 also induces the TGF-β pathway in porcine epithelial cells. We further characterize the host responses in an unbiased proteome analysis and identify 474 proteins regulated in worms fed Lb21 compared to control food. These include fatty acid CoA synthetase ACS-22, aspartic protease ASP-6 and vitellogenin VIT-2 which are important for Lb21-mediated MRSA resistance. Thus, Lb21 exerts its probiotic effect on C. elegans in a multifactorial manner. In summary, our study establishes a mechanistic basis for the antimicrobial potential of lactobacilli.

Timely Control of Gastrointestinal Eubiosis: A Strategic Pillar of Pig Health

The pig gastrointestinal tract (GIT) is an open ecosystem in which microorganisms and their host are mutually involved and continually adapt to different factors and problems which may or may not be host dependent or due to the production system. The aim of the present review is to highlight the factors affecting the GIT microbial balance in young pigs, focusing on the pre- and post-weaning phases, to define a road map for improving pig health and the production efficiency of the food chain. Birth and weaning body weight, physiological maturation, colostrum and milk (composition and intake), genetic background, environmental stressors and management practices, antibiotic use and diet composition are considered. Overall, there is a lack of knowledge regarding the effect that some factors, including weaning age, the use of creep feed, the composition of the colostrum and milk and the use of antibiotics, may have on the gut microbiome of piglets. Furthermore, the information on the gut microbiome of piglets is mainly based on the taxonomy description, while there is a lack of knowledge regarding the functional modification of the microbiota, essential for the exploitation of microbiota potential for modulating pig physiology.

NEGATIVE ION MASS SPECTROMETRY FOR THE ANALYSIS OF N-LINKED GLYCANS

N-glycans from glycoproteins are complex, branched structures whose structural determination presents many analytical problems. Mass spectrometry, usually conducted in positive ion mode, often requires extensive sample manipulation, usually by derivatization such as permethylation, to provide the necessary structure-revealing fragment ions. The newer but, so far, lesser used negative ion techniques, on the contrary, provide a wealth of structural information not present in positive ion spectra that greatly simplify the analysis of these compounds and can usually be conducted without the need for derivatization. This review describes the use of negative ion mass spectrometry for the structural analysis of N-linked glycans and emphasises the many advantages that can be gained by this mode of operation. Biosynthesis and structures of the compounds are described followed by methods for release of the glycans from the protein. Methods for ionization are discussed with emphasis on matrix-assisted laser desorption/ionization (MALDI) and methods for producing negative ions from neutral compounds. Acidic glycans naturally give deprotonated species under most ionization conditions. Fragmentation of negative ions is discussed next with particular reference to those ions that are diagnostic for specific features such as the branching topology of the glycans and substitution positions of moieties such as fucose and sulfate, features that are often difficult to identify easily by conventional techniques such as positive ion fragmentation and exoglycosidase digestions. The advantages of negative over positive ions for this structural work are emphasised with an example of a series of glycans where all other methods failed to produce a structure. Fragmentation of derivatized glycans is discussed next, both with respect to derivatives at the reducing terminus of the molecules, and to methods for neutralization of the acidic groups on sialic acids to both stabilize them for MALDI analysis and to produce the diagnostic fragments seen with the neutral glycans. The use of ion mobility, combined with conventional mass spectrometry is described with emphasis on its use to extract clean glycan spectra both before and after fragmentation, to separate isomers and its use to extract additional information from separated fragment ions. A section on applications follows with examples of the identification of novel structures from lower organisms and tables listing the use of negative ions for structural identification of specific glycoproteins, glycans from viruses and uses in the biopharmaceutical industry and in medicine. The review concludes with a summary of the advantages and disadvantages of the technique. © 2020 John Wiley & Sons Ltd. Mass Spec Rev.

Variations in porcine colostrum oligosaccharide composition between breeds and in association with sow maternal performance

Background

Oligosaccharides (OS) are indigestible carbohydrates naturally found in milk. The composition of porcine colostrum OS may influence the growth and the health of the neonate and consuming optimal concentrations of OS may reduce piglet susceptibility to illness. In this manner, targeted supplementation of animal feed with OS is being explored as a health management tool in the livestock industry. The variation in OS composition between different breeds of pig and its association with the litter performance is currently unknown. The aim of this study was to characterize the colostrum OS composition from sows of different breed and parity and correlate this data with sow maternal traits.

Methods

Eighty-three colostrum samples from parities 1 to 8 were gathered from 3 different breeds of sow: 44 Large White sows, 27 Landrace sows and 12 Duroc sows. Samples were taken between the birth of the first and the last piglet from sows that were not pharmacologically induced to farrow. OS were purified from the samples and analysed by MALDI-ToF mass spectrometry (21 OS compositions detected). The farrowing season and the maternal data were recorded for each sow, including the number of live piglets and the litter body weight at birth, at day (d) 3 and at weaning.

Results

Five OS compositions, including isomers of the bifidogenic Sialyllactose, Lacto-N-Tetraose and Lacto-N-Hexaose series, were detected in all the samples. Twelve other OS were identified in at least 50% of samples, and their abundances were affected by breed (P < 0.05; 6 of 12), marginally affected by season (P < 0.10; 3 of 12) and never by parity number. The abundances of each OS component were standardized by Z-score scaling (μ = 0 and SD = 1), transformed by principal component analysis, and four similarity clusters were generated. Cluster membership was associated with litter weight gain within 3 days (P = 0.063) and at weaning (P < 0.05), but not with piglet mortality within 3 days.

Conclusions

OS composition of colostrum may partially explain the variability in maternal performance within and between different breeds of sow. The obtained OS data can provide useful information for the development of novel prebiotic food supplements for suckling and weaning pigs.

Methodology and application of Escherichia coli F4 and F18 encoding infection models in post-weaning pigs

The enterotoxigenic Escherichia coli (ETEC) expressing F4 and F18 fimbriae are the two main pathogens associated with post-weaning diarrhea (PWD) in piglets. The growing global concern regarding antimicrobial resistance (AMR) has encouraged research into the development of nutritional and feeding strategies as well as vaccination protocols in order to counteract the PWD due to ETEC. A valid approach to researching effective strategies is to implement piglet in vivo challenge models with ETEC infection. Thus, the proper application and standardization of ETEC F4 and F18 challenge models represent an urgent priority. The current review provides an overview regarding the current piglet ETEC F4 and F18 challenge models; it highlights the key points for setting the challenge protocols and the most important indicators which should be included in research studies to verify the effectiveness of the ETEC challenge.

Based on the current review, it is recommended that the setting of the model correctly assesses the choice and preconditioning of pigs, and the timing and dosage of the ETEC inoculation. Furthermore, the evaluation of the ETEC challenge response should include both clinical parameters (such as the occurrence of diarrhea, rectal temperature and bacterial fecal shedding) and biomarkers for the specific expression of ETEC F4/F18 (such as antibody production, specific F4/F18 immunoglobulins (Igs), ETEC F4/F18 fecal enumeration and analysis of the F4/F18 receptors expression in the intestinal brush borders). On the basis of the review, the piglets’ response upon F4 or F18 inoculation differed in terms of the timing and intensity of the diarrhea development, on ETEC fecal shedding and in the piglets’ immunological antibody response. This information was considered to be relevant to correctly define the experimental protocol, the data recording and the sample collections. Appropriate challenge settings and evaluation of the response parameters will allow future research studies to comply with the replacement, reduction and refinement (3R) approach, and to be able to evaluate the efficiency of a given feeding, nutritional or vaccination intervention in order to combat ETEC infection.

Effect of Mucine 4 and Fucosyltransferase 1 genetic variants on gut homoeostasis of growing healthy pigs

Putative genetic markers have been associated with ETEC F4 (Mucine 4 [MUC4]; MUC4GG;CG as susceptible; MUC4CC as resistant) and F18 (Fucosyltransferase 1 [FUT1]; FUT1GG;AG as susceptible; FUT1AA as resistant) resistances respectively. In this study, 71 post-weaning pigs were followed from d0 (35 days old) to d42 (77 days of age) to investigate the effect of MUC4 or FUT1 genotypes on the mid-jejunal microbiota composition, pigs expression of genes related to inflammation (IL8, GPX2, REG3G, TFF3, CCL20 and LBPI) and glycomic binding pattern profile (Ulex europaeus agglutinin I [UEA] fucose-binding lectin and peanut agglutinin [PNA] galactose-specific), and on blood plasma targeted metabolomics profile, faecal score and performance parameters of growing healthy pigs. The MUC4 and FUT1 resistant genotypes improved the pigs' growth performance and had firmed faecal score susceptible genotypes in d0-d21 period. Pigs with MUC4GG genotype had a higher jejunal expression of genes relate to immune function (CCL20 and REG3G) than MUC4CG and MUC4CC pigs (p < 0.05). MUC4CG pigs had higher expression of TFF3 (implicated in mucosal integrity) than MUC4GG and MUC4CC (p < 0.05). FUT1 influenced the alpha- and beta-jejunal microbial indices. The FUT1AA group had a higher number of operational taxonomic units (OTUs) belonging to Lactobacillus genus, while FUT1GG group had a higher number of OTUs belonging to Veillonella genus. MUC4CC pigs had lower scores for UEA on brush borders and goblet cells in villi than MUC4GG (p < 0.05). FUT1AA pigs had lower UEA positivity and higher PNA positivity on brush borders and goblet cells than FUT1AG and FUT1GG (p < 0.05). Both FUT1 and MUC4 influenced the metabolic profile of healthy pigs. Results highlight the role of MUC4 and FUT1 on pig intestinal homoeostasis and improved the knowledge regarding the potential interaction between host genetics, gut microbiota composition and host metabolism in a healthy status.

The potential of pectin to impact pig nutrition and health: feeding the animal and its microbiome

The increasing efforts to substitute antibiotics and improve animal health combined with the acknowledgement of the role of gut microbiota in health have led to an elevated interest in the understanding on how fibre with prebiotic potential, such as pectin, can improve animal growth and health via direct or gut microbiota mediated effects. Various reports exist on the antiviral and antibacterial effects of pectin, as well as its potency as a modulator of the immune response and gut microbial community. Comprehensive insights into the potential of pectin to improve animal growth and health are currently still hampered by heterogeneity in the design of studies. Studies differ with regard to the dosage, molecular structure and source of the pectin implemented, as well as concerning the set of investigations of its effects on the host. Harmonisation of the study design including an in-depth analysis of the gut microbial community and its metabolome will aid to extract information on how pectin can impact growth and overall animal health. Studies with an increased focus on pectin structure such as on pectin-derived rhamnogalacturonan I (RG-I) are just starting to unravel pectin-structure-related effects on mammalian health.

Bovine colostrum-driven modulation of intestinal epithelial cells for increased commensal colonisation

Nutritional intake may influence the intestinal epithelial glycome and in turn the available attachment sites for bacteria. In this study, we tested the hypothesis that bovine colostrum may influence the intestinal cell surface and in turn the attachment of commensal organisms. Human HT-29 intestinal cells were exposed to a bovine colostrum fraction (BCF) rich in free oligosaccharides. The adherence of several commensal bacteria, comprising mainly bifidobacteria, to the intestinal cells was significantly enhanced (up to 52-fold) for all strains tested which spanned species that are found across the human lifespan. Importantly, the changes to the HT-29 cell surface did not support enhanced adhesion of the enteric pathogens tested. The gene expression profile of the HT-29 cells following treatment with the BCF was evaluated by microarray analysis. Many so called "glyco-genes" (glycosyltransferases and genes involved in the complex biosynthetic pathways of glycans) were found to be differentially regulated suggesting modulation of the enzymatic addition of sugars to glycoconjugate proteins. The microarray data was further validated by means of real-time PCR. The current findings provide an insight into how commensal microorganisms colonise the human gut and highlight the potential of colostrum and milk components as functional ingredients that can potentially increase commensal numbers in individuals with lower counts of health-promoting bacteria.

Effects of alpha-(1,2)-fucosyltransferase genotype variants on plasma metabolome, immune responses and gastrointestinal bacterial enumeration of pigs pre- and post-weaning

In pigs, the alpha-(1,2) fucosyltransferase (FUT1) gene has been highlighted for its properties in controlling the intestinal expression of enterotoxigenic E. coli (ETEC) F18 receptors; a pathogen causing edema disease and post-weaning diarrhoea. In this study, we hypothesized that pigs with different genotypes (ETEC F18 resistant (FUT1^AA) versus susceptible (FUT1^AG)) differed in following systemic and enteric responses: growth performance, plasma metabolic profiles, expression of candidate genes for intestinal mucosal homeostasis and immunity, number of selected bacteria and the concentration of short-chain fatty acids (SCFA) in faeces and digesta in piglets pre and post-weaning, and on the ETEC F18 adherence ex vivo. Genotype had the strongest impact on plasma metabolomic profile on day 7 and 28 of age. FUT1^AG piglets had higher level of N-methyl-2-pyrrolidinone, hippuric acid, oxindole, and 3-oxo-5-beta-chol-7-en-24-oic acid on day 7, and a higher level of guanosine on day 28 than that in the FUT1^AA piglets. FUT1^AA piglets had a higher level of betaine on day 7 and 3-methylguanine on day 28. On day 34 of age, the FUT1^AA pigs had higher levels of S-2-hydroxyglutarate, L-phenylalanine, tauroursodeoxycholic acid and an undetermined PC/LysoPC, while Ile Glu Phe Gly peptide and genistein 5-O-glucuronide, and PC (18:0/0:0) were at higher levels in the FUT1^AG piglets. FUT1 genotype did not affect the growth performance and expression of candidate genes. FUT1^AG piglets had a higher number of haemolytic bacteria in faeces and in digesta than that in FUT1^AA at 34 days of age. The colonic acetic acid concentration was highest in FUT1^AG piglets. FUT1 genotype may influence not only the expression of E. coli F18 receptors but could potentially impact the gut homeostasis and metabotype of piglets pre and post-weaning. Further investigations on the relation between FUT1 genotype and these aspects including the intestinal commensal microbiota will expand the knowledge on factors affecting the intestinal ecosystem.