The development of the mucosal immune system pre- and post-weaning: balancing regulatory and effector function

Dietary Intervention during Weaning and Development of Food Allergy: What Is the State of the Art?

Food allergy (FA) affects approximately 6-8% of children worldwide causing a significant impact on the quality of life of children and their families. In past years, the possible role of weaning in the development of FA has been studied. According to recent studies, this is still controversial and influenced by several factors, such as the type of food, the age at food introduction and family history. In this narrative review, we aimed to collect the most recent evidence about weaning and its role in FA development, organizing the gathered data based on both the type of study and the food. As shown in most of the studies included in this review, early food introduction did not show a potential protective role against FA development, and we conclude that further evidence is needed from future clinical trials.

The distribution and function of teleost IgT

Given the uniquely close relationship between fish and aquatic environments, fish mucosal tissues are constantly exposed to a wide array of pathogenic microorganisms in the surrounding water. To maintain mucosal homeostasis, fish have evolved a distinct mucosal immune system known as mucosal-associated lymphoid tissues (MALTs). These MALTs consist of key effector cells and molecules from the adaptive immune system, such as B cells and immunoglobulins (Igs), which play crucial roles in maintaining mucosal homeostasis and defending against external pathogen infections. Until recently, three primary Ig isotypes, IgM, IgD, and IgT, have been identified in varying proportions within the mucosal secretions of teleost fish. Similar to the role of mucosal IgA in mammals and birds, teleost IgT plays a predominant role in mucosal immunity. Following the identification of the IgT gene in 2005, significant advances have been made in researching the origin, evolution, structure, and function of teleost IgT. Multiple IgT variants have been identified in various species of teleost fish, underscoring the remarkable complexity of IgT in fish. Therefore, this study provides a comprehensive review of the recent advances in various aspects of teleost IgT, including its genomic and structural features, the diverse distribution patterns within various fish mucosal tissues (the skin, gills, gut, nasal, buccal, pharyngeal, and swim bladder mucosa), its interaction with mucosal symbiotic microorganisms, and its immune responses towards diverse pathogens, including bacteria, viruses, and parasites. We also highlight the existing research gaps in the study of teleost IgT, suggesting the need for further investigation into the functional aspects of IgT and IgT+ B cells. This research is aimed at providing valuable insights into the immune functions of IgT and the mechanisms underlying the immune responses of fish against infections.

The B Cell Response and Formation of Allergenic and Anti-Allergenic Antibodies in Food Allergy

Food allergies are a growing public health concern worldwide, especially in children and young adults. Allergen-specific IgE plays a central role in the pathogenesis of food allergies, but their titers poorly correlate with allergy development. Host immune systems yield allergen-specific immunoglobulin (Ig)A, IgE and IgG subclasses with low or high affinities and differential Fc N-glycosylation patterns that can affect the allergic reaction to food in multiple ways. High-affinity IgE is required to induce strong mast cell activation eventually leading to allergic anaphylaxis, while low-affinity IgE can even inhibit the development of clinically relevant allergic symptoms. IgA and IgG antibodies can inhibit IgE-mediated mast cell activation through various mechanisms, thereby protecting IgE-positive individuals from allergy development. The production of IgE and IgG with differential allergenic potential seems to be affected by the signaling strength of individual B cell receptors, and by cytokines from T cells. This review provides an overview of the diversity of the B cell response and the diverse roles of antibodies in food allergy.

Early feeding leads to molecular maturation of the gut mucosal immune system in suckling piglets

Introduction

Diet-microbiota-host interactions are increasingly studied to comprehend their implications in host metabolism and overall health. Keeping in mind the importance of early life programming in shaping intestinal mucosal development, the pre-weaning period can be utilised to understand these interactions in suckling piglets. The objective of this study was to investigate the consequences of early life feeding on the time-resolved mucosal transcriptional program as well as mucosal morphology.

Methods

A customised fibrous feed was provided to piglets (early-fed or EF group; 7 litters) from five days of age until weaning (29 days of age) in addition to sow's milk, whereas control piglets (CON; 6 litters) suckled mother's milk only. Rectal swabs, intestinal content, and mucosal tissues (jejunum, colon) were obtained pre- and post-weaning for microbiota analysis (16S amplicon sequencing) and host transcriptome analysis (RNA sequencing).

Results

Early feeding accelerated both microbiota colonisation as well as host transcriptome, towards a more "mature state", with a more pronounced response in colon compared to jejunum. Early feeding elicited the largest impact on the colon transcriptome just before weaning (compared to post-weaning time-points), exemplified by the modulation of genes involved in cholesterol and energy metabolism and immune response. The transcriptional impact of early feeding persisted during the first days post-weaning and was highlighted by a stronger mucosal response to the weaning stress, via pronounced activation of barrier repair reactions, which is a combination of immune activation, epithelial migration and "wound-repair" like processes, compared to the CON piglets.

Discussion

Our study demonstrates the potential of early life nutrition in neonatal piglets as a means to support their intestinal development during the suckling period, and to improve adaptation during the weaning transition.

Immune status of piglets during the first week of life: Current knowledge, significance and assessment

The immune system of neonate piglets differs from adult pigs in structure and competence. Although piglets are born immunocompetent, they are genuinely immunologically defenceless. To survive in the environment, piglets need passive protection provided by sow’s colostrum and milk when constantly exposed to numerous pathogens. Early assessment of piglets’ immune status may enable rapid intervention in case of detection of any deficiencies or disorders. Moreover, awareness of the piglets’ immunocompetence and the level of maternally-derived antibodies (MDA) may allow the creation of a proper vaccine schedule. Hence, extending knowledge of prenatal ontogeny of the porcine immune system, the immune status of neonate piglets’ and the immunological components of porcine colostrum is crucial. Since animal welfare has become a more critical element of animal production, new, non-invasive sampling methodologies are highly desirable for the evaluation of piglets’ immune status.

The clinical and immunological basis of early food introduction in food allergy prevention

IgE-mediated food allergy has an estimated prevalence of 6%-10% in developed countries. Allergen avoidance has long been the main focus in the prevention of food allergy and late solid food introduction after 6-12 months of age was recommended in high-risk infants. However, the rising prevalence of food allergy despite delayed exposure to allergens and the observations that IgE-mediated sensitization to food products could even occur before the introduction of solid foods resulted in a shift towards early solid food introduction as an attempt to prevent IgE-mediated food allergy. Since then, many trials focused on the clinical outcome of early allergen introduction and overall seem to point to a protective effect on the development of IgE-mediated food allergies. For non-IgE-mediated diseases of food allergy, evidence of early food introduction seems less clear. Moreover, data on the underlying immunological processes in early food introduction is lacking. The goal of this review is to summarize the available data of immunological changes in early food introduction to prevent IgE and non-IgE mediated food allergy.

Selecting the Best Animal Model of Parkinson's Disease for Your Research Purpose: Insight from in vivo PET Imaging Studies

Parkinson's disease (PD) is a debilitating neurodegenerative multisystem disorder leading to motor and non-motor symptoms in millions of individuals. Despite intense research, there is still no cure, and early disease biomarkers are lacking. Animal models of PD have been inspired by basic elements of its pathogenesis, such as dopamine dysfunction, alpha-synuclein accumulation, neuroinflammation and disruption of protein degradation, and these have been crucial for a deeper understanding of the mechanisms of pathology, the identification of biomarkers, and evaluation of novel therapies. Imaging biomarkers are non-invasive tools to assess disease progression and response to therapies; their discovery and validation have been an active field of translational research. Here, we highlight different considerations of animal models of PD that can be applied to future research, in terms of their suitability to answer different research questions. We provide the reader with important considerations of the best choice of model to use based on the disease features of each model, including issues related to different species. In addition, positron emission tomography studies conducted in PD animal models in the last 5 years are presented. With a variety of different species, interventions and genetic information, the choice of the most appropriate model to answer research questions can be daunting, especially since no single model recapitulates all aspects of this complex disorder. Appropriate animal models in conjunction with in vivo molecular imaging tools, if selected properly, can be a powerful combination for the assessment of novel therapies and developing tools for early diagnosis.

Developmental Changes of Immunity and Different Responses to Weaning Stress of Chinese Indigenous Piglets and Duroc Piglets during Suckling and Weaning Periods

To investigate developmental changes in immunity and different responses to weaning stress of piglets from different breeds during suckling and weaning periods, a total of 30 litters of Taoyuan black (TB) piglets, Xiangcun black (XB) piglets, and Duroc (DR) piglets (ten litters per breed) were selected at 1, 10, 21, and 24 days of age, respectively. The results showed that the liver index of TB piglets was higher at 10 days of age than that of the other days of age and breeds. Regardless of the days of age, TB and XB piglets had a higher plasma IgA level and lower ileal IgM level than in the DR piglets, and XB piglets had a lower plasma IgG level than the other breeds. TB and XB piglets had a higher IL-6 level and lower IL-17 level in plasma at 24 days of age than DR piglets, regardless of the days of age. The ileal levels of IL-2, IL-10, IFN-γ, and TNF-α were lower in the TB and XB piglets at 24 days of age than in the DR piglets. The ileal expression levels of IRAK1, CD14, MyD88, and NF-κB were down-regulated in the TB and XB piglets at 24 days of age compared to those in the DR piglets. These findings suggest that there were differences in the development of immune function among different pig breeds. Moreover, TB and XB piglets presented stronger resistance to weaning stress than the DR piglets, which may be related to the immune regulation mediated by the MyD88/NF-κB signaling pathway.

Weaning stress and intestinal health of piglets: A review

Weaning is considered to be one of the most critical periods in pig production, which is related to the economic benefits of pig farms. However, in actual production, many piglets are often subjected to weaning stress due to the sudden separation from the sow, the changes in diet and living environment, and other social challenges. Weaning stress often causes changes in the morphology and function of the small intestine of piglets, disrupts digestion and absorption capacity, destroys intestinal barrier function, and ultimately leads to reduced feed intake, increased diarrhea rate, and growth retardation. Therefore, correctly understanding the effects of weaning stress on intestinal health have important guiding significance for nutritional regulation of intestinal injury caused by weaning stress. In this review, we mainly reviewed the effects of weaning stress on the intestinal health of piglets, from the aspects of intestinal development, and intestinal barrier function, thereby providing a theoretical basis for nutritional strategies to alleviate weaning stress in mammals in future studies.

Early-life maternal deprivation affects the mother-offspring relationship in domestic pigs, as well as the neuroendocrine development and coping behavior of piglets

Early-life adversity may have programming effects on the psychological and physiological development of offspring. Domestic pigs (Sus scrofa) are an excellent model species for studying these effects because of their many physiological similarities to humans. Piglets from 10 sows were subjected to daily 2-h maternal deprivation on postnatal days (PND) 2–15 alone (DA) or in a group of littermates (DG). Control piglets (C) from 10 sows stayed with their mothers. Mother-offspring interaction, milk oxytocin, and cortisol were analyzed. An open-field/novel-object (OF/NO) test was performed with piglets on PNDs 16 and 40. Plasma cortisol and immune parameters were determined on PND 5 and 16. Two piglets from each group and sow were sacrificed on PND 20 and stress-related gene expression in the limbic system and prefrontal cortex (PFC), as well as splenic lymphocyte proliferative abilities, were examined. The milk cortisol of sows increased during the first separation of mother and offspring on the second day of lactation, whereas milk oxytocin did not change. The increase in cortisol by the OF/NO test on PND 16 was greater in C piglets than in DA and DG ones. DA piglets showed less agitated behavior than DG and C piglets in the OF/NO test at PND 16, but appeared more fearful. On PND 40, DA piglets showed more arousal than DG and C piglets in the OF/NO test. Neither plasma IgA nor N/L ratios in blood nor mitogen-induced proliferation of spleen lymphocytes were affected by deprivation. We found a higher mRNA expression of CRHR1 in the hypothalamus and a higher expression of MR in the hippocampus in DA piglets than in DG ones. The expression of GR, MR, and CRHR1 genes in the PFC was reduced by maternal deprivation, however, the expression of arginine vasopressin and oxytocin receptors was not affected. Repeated maternal deprivation induces sustained effects on stress reactivity and behavior of domestic piglets. Some of these effects were buffered by the presence of littermates. In addition, we found sex-specific differences in behavior and gene expression.

Neuro-immune crosstalk and food allergy: Focus on enteric neurons and mucosal mast cells

The nervous system and the immune system individually play important roles in regulating the processes necessary to maintain physiological homeostasis, respond to acute stress and protect against external threats. These two regulating systems for maintaining the living body had often been assumed to function independently. Allergies develop as a result of an overreaction of the immune system to substances that are relatively harmless to the body, such as food, pollen and dust mites. Therefore, it has been generally supposed that the development and pathogenesis of allergies can be explained through an immunological interpretation. Recently, however, neuro-immune crosstalk has attracted increasing attention. Consequently, it is becoming clear that there is close morphological proximity and physiological and pathophysiological interactions between neurons and immune cells in various peripheral tissues. Thus, researchers are now beginning to appreciate that neuro-immune interactions may play a role in tissue homeostasis and the pathophysiology of immune-mediated disease, but very little information is available on the molecular basis of these interactions. Mast cells are a part of the innate immune system implicated in allergic reactions and the regulation of host-pathogen interactions. Mast cells are ubiquitous in the body, and these cells are often found in close proximity to nerve fibers in various tissues, including the lamina propria of the intestine. Mast cells and neurons are thought to communicate bidirectionally to modulate neurophysiological effects and mast cell functions, which suggests that neuro-immune interactions may be involved in the pathology of allergic diseases.

Impact of Citrus Pulp or Inulin on Intestinal Microbiota and Metabolites, Barrier, and Immune Function of Weaned Piglets

We investigated the use of citrus pulp (CP) as a novel prebiotic capable of exerting microbiota and immunomodulating capacities to alleviate weaning stress. Inulin (IN), a well-known prebiotic, was used for comparison. Hundred and 28 male weaned piglets of 21 days old were assigned to 32 pens of 4 piglets each. Piglets were assigned to one of the four treatments, i.e., control, IN supplemented at 0.2% (IN0.2%), and CP supplemented either at 0.2% (CP0.2%) or at 2% (CP2%). On d10–11 and d31–32 post-weaning, one pig per pen was euthanized for intestinal sampling to evaluate the growth performance, chyme characteristics, small intestinal morphology, colonic inflammatory response and barrier integrity, metabolite profiles [gas chromatography-mass spectrometry (GC-MS), and liquid chromatography-mass spectrometry (LC-MS)], and microbial populations. The IN treatment and the two CP treatments induced higher small intestinal villus height to crypt depth ratios in comparison with the control diet at both sampling times. All treatments decreased acidic goblet cell absolute counts in the crypts in comparison to the control diet of the duodenum on d10–11 and d31–32. The gene expression of β-defensin 2 was downregulated in colonic tissues following the IN and CP2% inclusion on d31–32. On d31–32, piglets fed with IN and CP0.2% showed lower mRNA levels of occludin and claudin-3, respectively. Not surprisingly, flavonoids were observed in the colon in the CP treatments. Increased colonic acetate proportions on d10–11, at the expense of branched-chain fatty acid (BCFA) levels, were observed following the CP2% supplementation compared to the control diet, inferring a reduction of proteolytic fermentation in the hindgut. The beneficial microbial community Faecalibacterium spp. was promoted in the colon of piglets fed with CP2% on d10–11 (p = 0.04; false discovery rate (FDR) non-significant) and on d31–32 (p = 0.03; FDR non-significant) in comparison with the control diet. Additionally, on d31–32, CP2% increased the relative abundance of Megasphaera spp. compared to control values (p = 0.03; FDR non-significant). In conclusion, CP2% promoted the growth of beneficial bacterial communities in both post-weaning time points, modulating colonic fermentation patterns in the colon. The effects of CP supplementation were similar to those of IN and showed the potential as a beneficial feed supplement to alleviate weaning stress.

MicroRNA expression profiling during the suckling-to-weaning transition in pigs

Weaning induces physiological changes in intestinal development that affect pigs’ growth performance and susceptibility to disease. As a posttranscriptional regulator, microRNAs (miRNAs) regulate cellular homeostasis during intestinal development. We performed small RNA expression profiling in the small intestine of piglets before weaning (BW), 1 week after weaning (1W), and 2 weeks after weaning (2W) to identify weaning-associated differentially expressed miRNAs. We identified 38 differentially expressed miRNAs with varying expression levels among BW, 1W, and 2W. Then, we classified expression patterns of the identified miRNAs into four types. ssc-miR-196a and ssc-miR-451 represent pattern 1, which had an increased expression at 1W and a decreased expression at 2W. ssc-miR-499-5p represents pattern 2, which had an increased expression at 1W and a stable expression at 2W. ssc-miR-7135-3p and ssc-miR-144 represent pattern 3, which had a stable expression at 1W and a decreased expression at 2W. Eleven miRNAs (ssc-miR-542-3p, ssc-miR-214, ssc-miR-758, ssc-miR-4331, ssc-miR-105-1, ssc-miR-1285, ssc-miR-10a-5p, ssc-miR-4332, ssc-miR-503, ssc-miR-6782-3p, and ssc-miR-424-5p) represent pattern 4, which had a decreased expression at 1W and a stable expression at 2W. Moreover, we identified 133 candidate targets for miR-196a using a target prediction database. Gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses revealed that the target genes were associated with 19 biological processes, 4 cellular components, 8 molecular functions, and 7 KEGG pathways, including anterior/posterior pattern specification as well as the cancer, PI3K–Akt, MAPK, GnRH, and neurotrophin signaling pathways. These findings suggest that miRNAs regulate the development of the small intestine during the weaning process in piglets by anterior/posterior pattern specification as well as the cancer, PI3K–Akt, MAPK, GnRH, and neurotrophin signaling pathways.

Replacement of Metaphylactic Antimicrobial Therapy by Oral Administration of Ligilactobacillus salivarius MP100 in a Pig Farm

Antibiotic use in swine production contributes to the emergence and spread of resistant bacteria, which poses a threat on human health. Therefore, alternative approaches must be developed. The objective of this work was the characterization of the probiotic properties of a Ligilactobacillus salivarius strain isolated from sow's milk and its application as an inoculated fermented feed to pregnant sows and piglets. The study was carried in a farm in which metaphylactic use of antimicrobials (including zinc oxide) was eliminated at the time of starting the probiotic intervention, which lasted for 2 years. Feces from 8-week-old piglets were collected before and after the treatment and microbiological and biochemical analyses were performed. The procedure led to an increase in the concentrations of clostridia and lactobacilli-related bacteria. Parallel, an increase in the concentration of butyrate, propionate and acetate was observed and a notable reduction in the presence of antibiotic resistant lactobacilli became apparent. In conclusion, replacement of antimicrobials by a microbiota-friendly approach was feasible and led to positive microbiological and biochemical changes in the enteric environment.

A piglet model of iatrogenic rectosigmoid hypoganglionosis reveals the impact of the enteric nervous system on gut barrier function and microbiota postnatal development

BACKGROUND

Hirschsprung-associated enterocolitis physiopathology likely involves disturbed interactions between gut microbes and the host during the early neonatal period. Our objective was to create a neonatal porcine model of iatrogenic aganglionosis to evaluate the impact of the enteric nervous system (ENS) on microbiota and intestinal barrier postnatal development.

METHODS

Under general anesthesia, the rectosigmoid serosa of 5-day-old suckling piglets was exposed to 0.5% benzalkonium chloride solution (BAC, n = 7) or saline (SHAM, n = 5) for 1 h. After surgery, animals returned to their home-cage with the sow and littermates and were studied 21 days later.

RESULTS

BAC treatment induced partial aganglionosis with absence of myenteric plexus and reduced surface area of submucosal plexus ganglia (-58%, P < 0.05) in one third of the rectosigmoid circumference. Epithelial permeability of this zone was increased (conductance +63%, FITC-dextran flux +386%, horseradish-peroxidase flux +563%, P < 0.05). Tight junction protein remodeling was observed with decreased ZO-1 (-95%, P < 0.05) and increased claudin-3 and e-cadherin expressions (+197% and 61%, P < 0.05 and P = 0.06, respectively). BAC piglets harbored greater abundance of proinflammatory bacteria (Bilophila, Fusobacterium) compared to SHAM in the rectosigmoid lumen.

CONCLUSIONS

This large animal model demonstrates that hypoganglionosis is associated with dramatic defects of gut barrier function and establishment of proinflammatory bacteria.

Single-Blinded Study Highlighting the Differences between the Small Intestines of Neonatal and Weaned Piglets

Simple Summary

The gut mucosa of pigs, which contains intestinal epithelium and subepithelial immune cells, forms a barrier against microorganisms. Nonetheless, infectious diseases of the digestive tract remain the most frequent and recurrent conditions in the swine industry. Changes in intestinal morphology and structure primarily occur at birth and during weaning. However, the difference in the intestinal structures between neonatal and weaned piglets remains unclear. In this study, for the first time, we evaluated the differences in the small intestine between neonatal (0-day-old) and weaned piglets (21-day-old) and analyzed the morphology and immunological components of the small intestines of 0- and 21-day-old piglets, thereby providing preliminary data for future mechanistic studies.

Abstract

The gut is one of the body’s major immune structures, and the gut mucosa, which contains intestinal epithelium and subepithelial immune cells, is the primary site for eliciting local immune responses to foreign antigens. Intestinal immune system development in pigs is a transitional period during birth and weaning. This study compares the morphological and immunological differences in the small intestine of neonatal and weaned piglets to potentially prevent intestinal infectious diseases in neonatal piglets. Histological analyses of weaned piglet intestines showed increased crypt depth, higher IEL count, and larger ileal Peyer’s patches compared with those of neonates. Additionally, the ileal villi of weaned piglets were longer than those of neonatal piglets, and claudin-3 protein expression was significantly higher in weaned than in neonatal piglets. The numbers of CD3⁺ T, goblet, and secretory cells were also higher in the small intestines of weaned piglets than in those of neonates. No significant differences were observed in the secretory IgA-positive cell number in the jejunum of weaned and neonatal piglets. The mRNA expression of most pattern recognition receptors genes in the duodenum and jejunum was higher in the weaned than neonatal piglets; however, the opposite was true in the ileum. The mRNA levels of IL-1β and TNF-α in the jejunal and ileal mucosa were higher in weaned piglets than in neonatal piglets. There were significantly fewer CD3⁺, CD4⁺, and CD8⁺ T cells from peripheral blood-mononuclear cells in neonatal piglets. Our study provides insights regarding the different immune mechanisms within the small intestines of 0- and 21-day-old piglets. Studies on the additional developmental stages and how differences in the small intestines affect the response of pigs to pathogens remain warranted.

The Effects of Urbanization on the Infant Gut Microbiota and Health Outcomes

Humans and their gut microbiota have co-evolved over thousands of years, resulting in the establishment of a complex host-microbiota ecosystem. Early life environmental factors, such as delivery mode, nutrition, and medication use, have been shown to substantially affect both host-microbiota interactions and health outcomes. However, the effects of urbanization (characterized by the spectrum of rural and urban populations) on these early life events have been overlooked. A deeper understanding of the relationship between urbanization and microbiota development will allow for the identification of novel biological and social approaches that can be implemented to prevent and treat disease and promote maternal and infant/child health. The aim of this narrative review is to summarize how factors associated with urbanization differentially impact delivery mode, nutrition, and medication use, and how these changes subsequently affect the gut microbiota and health outcomes of infants. This narrative review also describes the important evidence gaps associated with these relationships and recommends actions that can be taken to improve the health of mothers and infants worldwide.

Effect of Maternal Diet and Medium Chain Fatty Acids Supplementation for Piglets on Their Digestive Tract Development, Structure, and Chyme Acidity as Well as Performance and Health Status

Simple Summary

Weaning is the most critical period of piglet rearing. During this time, pigs have not yet fully developed their intestinal tract and immune system; therefore, they are an easy target for pathogenic microorganisms that cause gastrointestinal diseases. In the last decade, several nutritional factors were studied to prevent gastrointestinal disorders in piglets. The present study aimed to evaluate the effect of oils for sows during late pregnancy and lactation on offspring performance. In addition, the study determined the effect of caprylic acid or medium-chain triglyceride oil in piglets’ feed on their intestinal structure development, fatty acids content of chyme, productive performance, and health status. Summarizing, the study showed that coconut oil fed to pregnant and lactating sows can markedly reduce the mortality of piglets during the weaning period and that caprylic acid and medium-chain fatty acid oil can be a good feed supplement in weaned piglet feed. The nutritional factors tested in the present study could be used in the diet of sows and piglets to improve the health of piglets and thus the efficiency of pig production.

Abstract

The objective of the present study was to evaluate the effect of oils for sows during late pregnancy and lactation on offspring performance. In addition, the effect of caprylic acid (C8) or medium-chain triglyceride oil (MCT) in piglets’ feed on their gut development, performance, and health status was determined. The experiment was conducted on 24 sows allocated to two treatments: diet with rapeseed oil or with coconut oil. Newborn piglets were randomly allocated to three treatments: feed with no supplement or supplemented with 0.3% MCT or with 0.3% C8. The results showed that both oils had no effect on sow reproductive rates; however, fatty acid patterns of milk differed significantly and the number of lost piglets was lower in sow fed with coconut oil. Both caprylic and MCT oil significantly improved piglet performance and villus height. These additives did not change triacylglycerol content in blood, but C8 lowered total cholesterol and MCT increased IgG content. It can be concluded that coconut oil fed to pregnant and lactating sows can markedly reduce the mortality of piglets and that caprylic acid and medium-chain fatty acid oil can be a good supplement in weaned piglet feed.

The pig as a model for immunology research

The pig is an omnivorous, monogastric species with many advantages to serve as an animal model for human diseases. There are very high similarities to humans in anatomy and functions of the immune system, e g., the presence of tonsils, which are absent in rodents. The porcine immune system resembles man for more than 80% of analyzed parameters in contrast to the mouse with only about 10%. The pig can easily be bred, and there are less emotional problems to use them as experimental animals than dogs or monkeys. Indwelling cannulas in a vein or lymphatic vessel enable repetitive stress-free sampling. Meanwhile, there are many markers available to characterize immune cells. Lymphoid organs, their function, and their role in lymphocyte kinetics (proliferation and migration) are reviewed. For long-term experiments, minipigs (e.g., Göttingen minipig) are available. Pigs can be kept under gnotobiotic (germfree) conditions for some time after birth to study the effects of microbiota. The effects of probiotics can be tested on the gut immune system. The lung has been used for extracorporeal preservation and immune engineering. After genetic modifications are established, the pig is the best animal model for future xenotransplantation to reduce the problem of organ shortage for organ transplantation. Autotransplantation of particles of lymphnodes regenerates in the subcutaneous tissue. This is a model to treat secondary lymphedema patients. There are pigs with cystic fibrosis and severe combined immune deficiency available.

Evaluation of different blends of medium-chain fatty acids, lactic acid, and monolaurin on nursery pig growth performance. Transl Anim Sci 2020;4:txaa024. [PMID: 32705023 DOI: 10.1093/tas/txaa024]

A total of 710 pigs (Line 400 × 200, DNA, Columbus, net energy (NE)) were used in two experiments (Exp. 1: initially, 6.3 ± 0.05 kg; Exp. 2: initially, 6.8 ± 0.05 kg) to evaluate the effects of two medium-chain fatty acid (MCFA) based products on nursery pig growth performance. Following their arrival at the nursery facility, pigs were randomized to pens (five pigs per pen) and allowed a 4-d acclimation period. Thereafter, pens of pigs were blocked by initial weight and randomized to dietary treatment. In Exp. 1, the dietary treatments were a dose titration of: 0%, 0.5%, 1.0%, or 2.0% MCFA-based additive, as well as a diet including 1.0% MCFA from a 1:1:1 blend of C6:0, C8:0, and C10:0. In Exp.2, dietary treatments consisted of a basal diet containing no MCFA (control), the control diet with a 1.0% inclusion of four different blends of MCFA, lactic acid, and monolaurin or a diet with 1.0% added MCFA (a 1:1:1 blend of C6:0, C8:0, and C10:0). The four blends consisted of 50% C6:0, 20% lactic acid, and increasing levels of monolaurin (0%, 10%, 20%, and 30%) at the expense of C12:0 (30%, 20%, 10%, and 0%). Treatment diets were formulated and manufactured in two dietary phases. Data were analyzed as a randomized complete block design with pen as the experimental unit. In Exp. 1, overall (days 0-34), increasing CaptiSURE increased (linear, P ≤ 0.014) average daily gain (ADG) and average daily feed intake (ADFI). Feed efficiency improved (quadratic, P = 0.002) with increasing CaptiSURE up to 1.0% of the diet with no benefit thereafter. There was no evidence for differences between pigs fed 1.0% CaptiSURE and pigs fed the 1.0% MCFA blend of C6:0, C8:0, and C10:0. In Exp. 2, overall (days 0-35), pigs fed the 1.0% 1:1:1 MCFA blend had increased (P < 0.034) ADFI and ADG resulting in 0.9 kg greater final weight (P = 0.014) compared with the control group. There was no evidence that the mean performance of pigs fed the four blends of MCFA, lactic acid, and monolaurin were different from the pigs fed the control diet. In summary, the addition of a 1.0% 1:1:1 blend of C6:0, C8:0, and C10:0 in nursery pig diets improved ADG, ADFI, and gain to feed ratio (G:F) compared with pigs fed the control diet. In addition, providing nursery pigs with the MCFA product CaptiSURE, up to 2% of the diet, resulted in linear improvements in ADG and ADFI. Altering the C12:0 to monolaurin ratio and adding lactic acid did not improve growth performance compared with pigs fed the control diet.

Review: innovation through research in the North American pork industry

This article involved a broad search of applied sciences for milestone technologies we deem to be the most significant innovations applied by the North American pork industry, during the past 10 to 12 years. Several innovations shifted the trajectory of improvement or resolved significant production limitations. Each is being integrated into practice, with the exception being gene editing technology, which is undergoing the federal approval process. Advances in molecular genomics have been applied to gene editing for control of porcine reproductive and respiratory syndrome and to identify piglet genome contributions from each parent. Post-cervical artificial insemination technology is not novel, but this technology is now used extensively to accelerate the rate of genetic progress. A milestone was achieved with the discovery that dietary essential fatty acids, during lactation, were limiting reproduction. Their provision resulted in a dose-related response for pregnancy, pregnancy maintenance and litter size, especially in maturing sows and ultimately resolved seasonal infertility. The benefit of segregated early weaning (12 to 14 days of age) was realized for specific pathogen removal for genetic nucleus and multiplication. Application was premature for commercial practice, as piglet mortality and morbidity increased. Early weaning impairs intestinal barrier and mucosal innate immune development, which coincides with diminished resilience to pathogens and viability later in life. Two important milestones were achieved to improve precision nutrition for growing pigs. The first involved the updated publication of the National Research Council nutrient requirements for pigs, a collaboration between scientists from America and Canada. Precision nutrition advanced further when ingredient description, for metabolically available amino acids and net energy (by source plant), became a private sector nutrition product. The past decade also led to fortuitous discoveries of health-improving components in ingredients (xylanase, soybeans). Finally, two technologies converged to facilitate timely detection of multiple pathogens in a population: oral fluids sampling and polymerase chain reaction (PCR) for pathogen analysis. Most critical diseases in North America are now routinely monitored by oral fluid sampling and prepared for analysis using PCR methods.

Mucosal and systemic immune responses to Aujeszky's disease virus (ADV) in early vaccinated piglets

Newborn humans and animals are highly susceptible to viral infections. The Aujeszky´s disease virus (ADV) is a porcine herpes virus 1 which infects the respiratory tract and is lethal during the first weeks of life. Current intramuscular vaccines, applied at weaning, induce poor mucosal immunity and frequently fail to prevent and control the disease. Additionally, early vaccination has not been studied thoroughly. Therefore, we studied a systemic/mucosal route of immunization using an inactivated ADV vaccine in two-and fourteen-day-old groups of unweaned SPF miniature Vietnamese pigs, measuring the anti ADV antibody (ELISA) and cytokine (qPCR) responses in systemic and mucosal samples. The results showed that the serum ADV-specific IgG response was higher in the 14-day groups. However, the nasal IgA responses were similar in immunized groups, although the response in saliva was higher in the 2-day old group. Moreover, in vitro ADV stimulated peripheral blood mononuclear cells and lung cells from immunized pigs showed higher IFN-γ mRNA production in the 14-day old group than in younger animals and similar levels of IL-4 and IL-10 transcripts. Our data suggest that early mucosal immunization induce humoral and cellular systemic and mucosal immune responses against ADV in young pigs and younger animals may have compensatory mechanisms to overcome early immaturity and maternal-driven immune interference. Therefore, early protection in susceptible animals could be induced using this immunization protocol, opening the possibility for its application against other viral pathogens of pigs and for traslational studies in humans.

Plasticity of intestinal gene expression profile signatures reflected by nutritional interventions in piglets

BACKGROUND

Immediately after birth, the porcine intestine rapidly develops morphologically, functionally, and immunologically. The jejunum, the second part of the small intestine, is of importance for nutrient uptake and immune surveillance. To study the early postnatal development of the jejunum, a meta-analysis was performed on different transcriptomic datasets. These datasets were acquired from different experimental in-house studies or from experiments described in literature of porcine jejunum mucosa. Gene expression was measured under different experimental interventions, such as nutritional intervention, at various time-points (age).

RESULTS

The studies included in the meta-analysis provided gene expression data for various time-points (piglet ages) for piglets that had received a treatment versus control piglets. In separate studies, treatments were administered to the sow (i.e. amoxicillin), or nutritional supplementation directly to the piglets with medium chain fatty acids (MCFAs), and oral administration of fructooligosaccharides (FOS) or a high dose of zinc-oxide, respectively. In the meta-analysis, genes were grouped into 16 clusters according to their temporal gene expression profiles for control piglets, i.e. the changes of gene expression level over time. Functional analysis showed that these temporal profile clusters had different dominant processes, such as immune related processes or barrier function. Transcriptomics data of treatment piglets was subsequently superimposed over the control temporal profiles. In this way we could investigate which temporal profile clusters (and which biological processes) were modulated by the treatments. Interestingly, not all 16 temporal profiles were modulated.

CONCLUSIONS

We showed that it is possible to re-use (publicly available) transcriptomics data and produce temporal gene expression profiles for control piglets with overexpression of genes representing specific biological processes. Subsequently, by superimposing gene expression data from (nutritional) intervention studies we observed deviations from some of these reference profile(s) and thus the plasticity of the system. By employing this meta-analysis approach we highlighted the importance of birth and weaning and the underlying biological processes.

Timing of Food Introduction and the Risk of Food Allergy

Given that the prevalence of pediatric IgE-mediated food allergies (FA) has followed a substantive increase in recent decades, nowadays, a research challenge is to establish whether the weaning strategy can have a role in FA prevention. In recent decades, several studies have demonstrated that delayed exposure to allergenic foods did not reduce the risk of FA, leading to the publication of recent guidelines which recommend against delaying the introduction of solid foods after 4–6 months of age, both in high- and low-risk infants, in order to prevent food allergy. In the present review, focusing on cow’s milk protein, hen’s eggs, peanuts, soy, wheat and fish, we describe the current scientific evidence on the relationship between timing of these foods’ introduction in infants’ diet and allergy development.

Toward rational selection criteria for selection of probiotics in pigs

An accurate understanding of properties of probiotics is a prerequisite for selecting probiotic organisms for use in swine production. This review aims to review selection criteria for probiotic organism in swine. The systematically investigated ecological history rather than the source of isolates should be regarded as the natural origin of probiotic strains, which helps to correct the inconsistencies arising from incorrect identification of the source. Moreover, in vivo studies are suggested as follow-up assessment to validate the characteristics of probiotic predicted by in vitro experiments. In addition, the intended probiotic effect depends on the age of the animal and disease prevention in young animals may require different probiotic strains when compared to growth promotion in older animals. With adequate selection criteria, the inclusion of probiotic in feed supplementation is a promising way to exert positive effects on sows, newborns, weanling animals and grower-finisher pigs. Both host-adapted probiotics and nomadic probiotics can be applied for pathogen inhibition but host adapted organisms appear to have a different mode of action. Host-adapted probiotic strains are likely to be associated with exclusive colonization while the nomadic or environmental strain exert better immune stimulating functions. Strains with potent enzymatic activity are fitter for grower pigs favoring feed digestion and enhancing growth performance.

Placebo-controlled study on the effects of oral administration of Allium sativum L in postweaning piglets

Postweaning diarrhoea (PWD) due to Escherichia coli is an economically important disease in pig production. In this placebo-controlled study performed in Switzerland, the effects of oral supplementation of Allium sativum L. (garlic, AS) on performance (bodyweight (BW) and daily weight gain (DWG)) and health (body condition and clinical score) were investigated in postweaning piglets. Piglets (n=600) were randomly assigned to the treatment groups (placebo, AS or colistin) and observed from birth until three weeks postweaning. The treatments were administered for the first two weeks postweaning. Faecal dry matter (FDM) and coliform bacteria on pen level were measured weekly. Data were analysed using generalised mixed-effect models in R. BW and DWG of the AS group were significantly higher compared with placebo in the third week postweaning. No differences in body condition and FDM were observed. The clinical score of AS-treated animals was significantly better compared with the colistin group. About 33 per cent of the piglets of the AS and the placebo group had to be treated with antibiotics due to the occurrence of severe PWD. The major finding of this study showed that AS supplementation increased growth performance and improved clinical health, but did not reduce the incidence and severity of PWD.

Mucosal immunoglobulins protect the olfactory organ of teleost fish against parasitic infection

The olfactory organ of vertebrates receives chemical cues present in the air or water and, at the same time, they are exposed to invading pathogens. Nasal-associated lymphoid tissue (NALT), which serves as a mucosal inductive site for humoral immune responses against antigen stimulation in mammals, is present also in teleosts. IgT in teleosts is responsible for similar functions to those carried out by IgA in mammals. Moreover, teleost NALT is known to contain B-cells and teleost nasal mucus contains immunoglobulins (Igs). Yet, whether nasal B cells and Igs respond to infection remains unknown. We hypothesized that water-borne parasites can invade the nasal cavity of fish and elicit local specific immune responses. To address this hypothesis, we developed a model of bath infection with the Ichthyophthirius multifiliis (Ich) parasite in rainbow trout, Oncorhynchus mykiss, an ancient bony fish, and investigated the nasal adaptive immune response against this parasite. Critically, we found that Ich parasites in water could reach the nasal cavity and successfully invade the nasal mucosa. Moreover, strong parasite-specific IgT responses were detected in the nasal mucus, and the accumulation of IgT⁺ B-cells was noted in the nasal epidermis after Ich infection. Strikingly, local IgT⁺ B-cell proliferation and parasite-specific IgT generation were found in the trout olfactory organ, providing new evidence that nasal-specific immune responses were induced locally by a parasitic challenge. Overall, our findings suggest that nasal mucosal adaptive immune responses are similar to those reported in other fish mucosal sites and that an antibody system with a dedicated mucosal Ig performs evolutionary conserved functions across vertebrate mucosal surfaces.

The olfactory organ is a vitally important chemosensory organ in vertebrates but it is also continuously stimulated by pathogenic microorganisms in the external environment. In mammals and birds, nasopharynx-associated lymphoid tissue (NALT) is considered one of the first lines of immune defense against inhaled antigens and in bony fish, protecting against water-borne infections. However, although B-cells and immunoglobulins (Igs) have been found in teleost NALT, the defensive mechanisms of parasite-specific immune responses after pathogen challenge in the olfactory organ of teleost fish remain poorly understood. Considering that the NALT of all vertebrates has been subjected to similar evolutionary forces, we hypothesize that mucosal Igs play a critical role in the defense of olfactory systems against parasites. To confirm this hypothesis, we show the local proliferation of IgT⁺ B-cells and production of pathogen-specific IgT within the nasal mucosa upon parasite infection, indicating that parasite-specific IgT is the main Ig isotype specialized for nasal-adaptive immune responses. From an evolutionary perspective, our findings contribute to expanding our view of nasal immune systems and determining the fate of the host–pathogen interaction.

Impact of dietary spray-dried bovine plasma addition on pigs infected with porcine epidemic diarrhea virus

Experimental data suggest that the addition of spray-dried plasma (SDP) to pig feed may enhance antibody responses against certain pathogens and negatively impact virus survival. The benefit of SDP on Escherichia coli infection is well documented. The aim of this study was to determine the effect of bovine SDP (BovSDP) in the pig diet on acute porcine epidemic diarrhea virus (PEDV) infection. A total of 16 3-wk-old conventional crossbred pigs were used and divided into three groups. Treatments included 1) a negative control group fed a commercial diet and sham inoculated with commercial liquid porcine plasma (n = 3), 2) a positive control group fed a commercial diet and inoculated with PEDV-spiked porcine plasma (PEDV; n = 8), and 3) a third group of pigs fed the commercial diet with inclusion of 5% spray-dried bovine plasma and inoculated with PEDV-spiked porcine plasma (BovSDP; n = 5). Although clinical signs associated with PEDV infection were mild in the BovSDP group, two of eight pigs in the PEDV group developed moderate clinical disease and had to be euthanized. The PEDV IgG and IgA antibody levels and prevalence rates were significantly (P < 0.05) higher in the PEDV–BovSDP group compared with the PEDV group at 7 d postinoculation. The average fecal PEDV RNA shedding time was 7.2 ± 1.0 d for the PEDV–BovSDP group and 9.3 ± 1.1 d for the PEDV group with an overall time to clearance of PEDV shedding of 11 d for PEDV–BovSDP pigs and at least 14 d for PEDV pigs, which was not different (P = 0.215). The results indicate that addition of BovSDP induced an earlier anti-PEDV antibody response in pigs experimentally infected with PEDV thereby reducing clinical disease and the amount and duration of viral shedding during acute PEDV infection.

iTRAQ-based quantitative proteomic analysis of alterations in the intestine of Hu sheep under weaning stress

When Lambs are weaned off ewe's milk, metabolic, structural, and functional changes often occur in the small intestine. Because information on the effects of weaning stress on the proteome of the intestine is limited, an animal model was established with eight pairs of twin lambs divided into artificially reared and ewe-reared groups, which was followed by proteome analysis using iTRAQ technology. Changes occurred in the morphology of the intestine and 5,338 proteins in three biological replicates with less than a 1.2% false discovery rate were identified and quantified. Among them, a subset of 389 proteins were screened as significantly up- (143) and down-regulated (246) in artificially reared compared with ewe-reared. According to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis, the differentially expressed proteins that were strongly down-regulated were enriched in immune system processes, biological adhesion, and metabolic processes. The up-regulated proteins were enriched in gene expression, cellular biosynthetic processes, ribosome and RNA binding in response to weaning stress. A series of proteins associated with intestine morphology and immune function were identified, and levels of the mRNAs encoding these proteins were analyzed by real-time quantitative reverse transcription PCR. The results of this study increased our understanding of the response of lambs weaned off ewe's milk and helped to determine the mechanisms underlying weaning stress.

Early-Life Nutritional Factors and Mucosal Immunity in the Development of Autoimmune Diabetes

Type 1 diabetes (T1D) is an immune-mediated disease with a strong genetic basis but might be influenced by non-genetic factors such as microbiome development that “programs” the immune system during early life as well. Factors influencing pathogenesis, including a leaky intestinal mucosal barrier, an aberrant gut microbiota composition, and altered immune responsiveness, offer potential targets for prevention and/or treatment of T1D through nutritional or pharmacologic means. In this review, nutritional approaches during early life in order to protect against T1D development have been discussed. The critical role of tolerogenic dendritic cells in central and peripheral tolerance has been emphasized. In addition, since the gut microbiota affects the development of T1D through short-chain fatty acid (SCFA)-dependent mechanisms, we hypothesize that nutritional intervention boosting SCFA production may be used as a novel prevention strategy. Current retrospective evidence has suggested that exclusive and prolonged breastfeeding might play a protective role against the development of T1D. The beneficial properties of human milk are possibly attributed to its bioactive components such as unique immune-modulatory components human milk oligosaccharides and metabolites derived thereof, including SCFAs. These components might play a key role in healthy immune development and creating a fit and resilient immune system in early and later life.

Comparison of clinical and immunological findings in gnotobiotic piglets infected with Escherichia coli O104:H4 outbreak strain and EHEC O157:H7

Background

Shiga toxin (Stx) producing Escherichia coli (E. coli) (STEC) is the most frequent cause of diarrhoea-positive haemolytic uraemic syndrome (D + HUS) in humans. In 2011, a huge outbreak with an STEC O104:H4 strain in Germany highlighted the limited possibilities for causative treatment of this syndrome. The responsible STEC strain was found to combine Stx production with adherence mechanisms normally found in enteroaggregative E. coli (EAEC). Pathotypes of E. coli evolve and can exhibit different adhesion mechanisms. It has been shown previously that neonatal gnotobiotic piglets are susceptible for infection with STEC, such as STEC O157:H7 as well as for EAEC, which are considered to be the phylogenetic origin of E. coli O104:H4. This study was designed to characterise the host response to infection with the STEC O104:H4 outbreak strain in comparison to an STEC O157:H7 isolate by evaluating clinical parameters (scoring) and markers of organ dysfunction (biochemistry), as well as immunological (flow cytometry, assessment of cytokines/chemokines and acute phase proteins) and histological alterations (light- and electron microscopy) in a gnotobiotic piglet model of haemolytic uraemic syndrome.

Results

We observed severe clinical symptoms, such as diarrhoea, dehydration and neurological disorders as well as attaching-and-effacing lesions (A/E) in the colon in STEC O157:H7 infected piglets. In contrast, STEC O104:H4 challenged animals exhibited only mild clinical symptoms including diarrhoea and dehydration and HUS-specific/severe histopathological, haematological and biochemical alterations were only inconsistently presented by individual piglets. A specific adherence phenotype of STEC O104:H4 could not be observed. Flow cytometric analyses of lymphocytes derived from infected animals revealed an increase of natural killer cells (NK cells) during the course of infection revealing a potential role of this subset in the anti-bacterial activity in STEC disease.

Conclusions

Unexpectedly, E. coli O104:H4 infection caused only mild symptoms and minor changes in histology and blood parameters in piglets. Outcome of the infection trial does not reflect E. coli O104:H4 associated human disease as observed during the outbreak in 2011. The potential role of cells of the innate immune system for STEC related disease pathogenesis should be further elucidated.

Improvement of Therapeutic Efficacy of Oral Immunotherapy in Combination with Regulatory T Cell-Inducer Kakkonto in a Murine Food Allergy Model

Oral immunotherapy (OIT) has been considered a promising approach for food allergies (FAs). However, the current OIT strategy is limited in terms of the long-term efficacy and safety. We have previously demonstrated that kakkonto, a traditional Japanese herbal medicine, suppresses the occurrence of allergic symptoms in a murine model of ovalbumin (OVA)-induced FA, which is attributed to the induction of the Foxp3⁺ CD4⁺ regulatory T cells. In this study, we established an OIT model using the FA mice with already established allergic symptoms and determined whether kakkonto could improve the efficacy of OIT. The OIT method consisted of initially administrating a very small amount of OVA and slowly increasing the amount. Allergic symptoms decreased in the OIT-treated FA mice. OIT significantly downregulated Th2 immune response-related gene expression in the FA mouse colon, and decreased the level of mouse mast cell protease-1, a marker of mast cell degranulation in the FA mouse plasma. Moreover, the concomitant use of kakkonto significantly enhanced the effectiveness of OIT on the allergic symptoms, and the combination therapy further suppressed the Th2 immune responses and the mast cell degranulation. In addition, OIT significantly increased the population of Foxp3⁺ CD4⁺ regulatory T cells in the FA mouse colon, and this population was further increased by OIT in combination with kakkonto. Furthermore, the combined therapy with kakkonto reduced the expression of RA-degrading enzyme CYP26B1 mRNA in the FA mouse colon. These findings indicated that the combination of OIT with kakkonto represents a promising approach for FA treatment.

Macrophage colony-stimulating factor (CSF1) controls monocyte production and maturation and the steady-state size of the liver in pigs

Macrophage colony-stimulating factor (CSF1) is an essential growth and differentiation factor for cells of the macrophage lineage. To explore the role of CSF1 in steady-state control of monocyte production and differentiation and tissue repair, we previously developed a bioactive protein with a longer half-life in circulation by fusing pig CSF1 with the Fc region of pig IgG1a. CSF1-Fc administration to pigs expanded progenitor pools in the marrow and selectively increased monocyte numbers and their expression of the maturation marker CD163. There was a rapid increase in the size of the liver, and extensive proliferation of hepatocytes associated with increased macrophage infiltration. Despite the large influx of macrophages, there was no evidence of liver injury and no increase in circulating liver enzymes. Microarray expression profiling of livers identified increased expression of macrophage markers, i.e., cytokines such as TNF, IL1, and IL6 known to influence hepatocyte proliferation, alongside cell cycle genes. The analysis also revealed selective enrichment of genes associated with portal, as opposed to centrilobular regions, as seen in hepatic regeneration. Combined with earlier data from the mouse, this study supports the existence of a CSF1-dependent feedback loop, linking macrophages of the liver with bone marrow and blood monocytes, to mediate homeostatic control of the size of the liver. The results also provide evidence of safety and efficacy for possible clinical applications of CSF1-Fc.

Early weaning is beneficial to prevent atopic dermatitis occurrence in young children

BACKGROUND

Epidemiological data on infant feeding practices and allergic diseases are controversial. The purpose of this study was to explore the association of early weaning with the occurrence of atopic dermatitis (AD).

METHODS

We conducted a matched case-control study on incident physician-diagnosed AD in early childhood including 451 cases and 451 controls. Data on several factors, including feeding practices, were collected through an interviewer-administered questionnaire. Odds ratios (OR) and the corresponding 95% confidence intervals (CIs) were estimated through logistic regression models, conditioned on study center, age, sex, and period of interview, and adjusted for potential confounders.

RESULTS

Early weaning, defined as the introduction of solid foods at 4 or 5 months of age, was inversely related to the risk of AD, with children weaned at 4 months having lower AD risk (OR = 0.41, 95% CI, 0.20-0.87) compared to those exclusively breastfed. Similar results were observed for weaning started at 5 months of age (OR = 0.39, 95% CI, 0.18-0.83). This association persisted when children with and without family history of allergy were considered separately. Prolonged partial breastfeeding (breastmilk plus milk formulas) was not associated with AD. Consistently, the introduction of a high number of different solid foods reduced the risk of AD (P trend = 0.02 at 4 months of age and P trend = 0.04 at 5 months).

CONCLUSION

Our data provide evidence against the preventing role of prolonged exclusive (but not partial) breastfeeding in AD occurrence and confirm recent results indicating a beneficial role of early weaning in AD.

Critical review evaluating the pig as a model for human nutritional physiology

The present review examines the pig as a model for physiological studies in human subjects related to nutrient sensing, appetite regulation, gut barrier function, intestinal microbiota and nutritional neuroscience. The nutrient-sensing mechanisms regarding acids (sour), carbohydrates (sweet), glutamic acid (umami) and fatty acids are conserved between humans and pigs. In contrast, pigs show limited perception of high-intensity sweeteners and NaCl and sense a wider array of amino acids than humans. Differences on bitter taste may reflect the adaptation to ecosystems. In relation to appetite regulation, plasma concentrations of cholecystokinin and glucagon-like peptide-1 are similar in pigs and humans, while peptide YY in pigs is ten to twenty times higher and ghrelin two to five times lower than in humans. Pigs are an excellent model for human studies for vagal nerve function related to the hormonal regulation of food intake. Similarly, the study of gut barrier functions reveals conserved defence mechanisms between the two species particularly in functional permeability. However, human data are scant for some of the defence systems and nutritional programming. The pig model has been valuable for studying the changes in human microbiota following nutritional interventions. In particular, the use of human flora-associated pigs is a useful model for infants, but the long-term stability of the implanted human microbiota in pigs remains to be investigated. The similarity of the pig and human brain anatomy and development is paradigmatic. Brain explorations and therapies described in pig, when compared with available human data, highlight their value in nutritional neuroscience, particularly regarding functional neuroimaging techniques.

Tissue-specific mRNA expression profiles of porcine Toll-like receptors at different ages in germ-free and conventional pigs

Toll-like receptors (TLRs), key initiators of innate immune responses, recognize antigens and are essential in linking innate and adaptive immune responses. Misrecognition and over-stimulation/expression of TLRs may contribute to the development of chronic inflammatory diseases and autoimmune diseases. However, appropriate and mature TLR responses are associated with the establishment of resistance against some infectious diseases. In this study, we assessed the mRNA expression profile of TLRs 1-10 in splenic and ileal mononuclear cells (MNCs) and dendritic cells (DCs) of germ-free (GF) and conventional pigs at different ages. We found that the TLR mRNA expression profiles were distinct between GF and conventional pigs. The expression profiles were also significantly different between splenic and ileal MNCs/DCs. Comparison of the TLR expression profiles in GF and conventional newborn and young pigs demonstrated that exposure to commensal microbiota may play a more important role than age in TLR mRNA expression profiles. To our knowledge, this is the first report that systematically assesses porcine TLRs 1-10 mRNA expression profiles in MNCs and DCs from GF and conventional pigs at different ages. These results further highlighted that the commensal microbiota of neonates play a critical role through TLR signaling in the development of systemic and mucosal immune systems.

Miniature Swine for Preclinical Modeling of Complexities of Human Disease for Translational Scientific Discovery and Accelerated Development of Therapies and Medical Devices

Noncommunicable diseases, including cardiovascular disease, diabetes, chronic respiratory disease, and cancer, are the leading cause of death in the world. The cost, both monetary and time, of developing therapies to prevent, treat, or manage these diseases has become unsustainable. A contributing factor is inefficient and ineffective preclinical research, in which the animal models utilized do not replicate the complex physiology that influences disease. An ideal preclinical animal model is one that responds similarly to intrinsic and extrinsic influences, providing high translatability and concordance of preclinical findings to humans. The overwhelming genetic, anatomical, physiological, and pathophysiological similarities to humans make miniature swine an ideal model for preclinical studies of human disease. Additionally, recent development of precision gene-editing tools for creation of novel genetic swine models allows the modeling of highly complex pathophysiology and comorbidities. As such, the utilization of swine models in early research allows for the evaluation of novel drug and technology efficacy while encouraging redesign and refinement before committing to clinical testing. This review highlights the appropriateness of the miniature swine for modeling complex physiologic systems, presenting it as a highly translational preclinical platform to validate efficacy and safety of therapies and devices.

The human milk oligosaccharide 2'-fucosyllactose modulates CD14 expression in human enterocytes, thereby attenuating LPS-induced inflammation

BACKGROUND

A major cause of enteric infection, Gram-negative pathogenic bacteria activate mucosal inflammation through lipopolysaccharide (LPS) binding to intestinal toll-like receptor 4 (TLR4). Breast feeding lowers risk of disease, and human milk modulates inflammation.

OBJECTIVE

This study tested whether human milk oligosaccharides (HMOSs) influence pathogenic Escherichia coli-induced interleukin (IL)-8 release by intestinal epithelial cells (IECs), identified specific proinflammatory signalling molecules modulated by HMOSs, specified the active HMOS and determined its mechanism of action.

METHODS

Models of inflammation were IECs invaded by type 1 pili enterotoxigenic E. coli (ETEC) in vitro: T84 modelled mature, and H4 modelled immature IECs. LPS-induced signalling molecules co-varying with IL-8 release in the presence or absence of HMOSs were identified. Knockdown and overexpression verified signalling mediators. The oligosaccharide responsible for altered signalling was identified.

RESULTS

HMOSs attenuated LPS-dependent induction of IL-8 caused by ETEC, uropathogenic E. coli, and adherent-invasive E. coli (AIEC) infection, and suppressed CD14 transcription and translation. CD14 knockdown recapitulated HMOS-induced attenuation. Overexpression of CD14 increased the inflammatory response to ETEC and sensitivity to inhibition by HMOSs. 2'-fucosyllactose (2'-FL), at milk concentrations, displayed equivalent ability as total HMOSs to suppress CD14 expression, and protected AIEC-infected mice.

CONCLUSIONS

HMOSs and 2'-FL directly inhibit LPS-mediated inflammation during ETEC invasion of T84 and H4 IECs through attenuation of CD14 induction. CD14 expression mediates LPS-TLR4 stimulation of portions of the 'macrophage migration inhibitory factors' inflammatory pathway via suppressors of cytokine signalling 2/signal transducer and activator of transcription 3/NF-κB. HMOS direct inhibition of inflammation supports its functioning as an innate immune system whereby the mother protects her vulnerable neonate through her milk. 2'-FL, a principal HMOS, quenches inflammatory signalling.

Obesity-Driven Gut Microbiota Inflammatory Pathways to Metabolic Syndrome

The intimate interplay between immune system, metabolism, and gut microbiota plays an important role in controlling metabolic homeostasis and possible obesity development. Obesity involves impairment of immune response affecting both innate and adaptive immunity. The main factors involved in the relationship of obesity with inflammation have not been completely elucidated. On the other hand, gut microbiota, via innate immune receptors, has emerged as one of the key factors regulating events triggering acute inflammation associated with obesity and metabolic syndrome. Inflammatory disorders lead to several signaling transduction pathways activation, inflammatory cytokine, chemokine production and cell migration, which in turn cause metabolic dysfunction. Inflamed adipose tissue, with increased macrophages infiltration, is associated with impaired preadipocyte development and differentiation to mature adipose cells, leading to ectopic lipid accumulation and insulin resistance. This review focuses on the relationship between obesity and inflammation, which is essential to understand the pathological mechanisms governing metabolic syndrome.

The evolution of nasal immune systems in vertebrates

The olfactory organs of vertebrates are not only extraordinary chemosensory organs but also a powerful defense system against infection. Nasopharynx-associated lymphoid tissue (NALT) has been traditionally considered as the first line of defense against inhaled antigens in birds and mammals. Novel work in early vertebrates such as teleost fish has expanded our view of nasal immune systems, now recognized to fight both water-borne and air-borne pathogens reaching the olfactory epithelium. Like other mucosa-associated lymphoid tissues (MALT), NALT of birds and mammals is composed of organized lymphoid tissue (O-NALT) (i.e., tonsils) as well as a diffuse network of immune cells, known as diffuse NALT (D-NALT). In teleosts, only D-NALT is present and shares most of the canonical features of other teleost MALT. This review focuses on the evolution of NALT in vertebrates with an emphasis on the most recent findings in teleosts and lungfish. Whereas teleost are currently the most ancient group where NALT has been found, lungfish appear to be the earliest group to have evolved primitive O-NALT structures.

Recommendations on complementary feeding for healthy, full-term infants

Weaning (or introduction of complementary feeding) is a special and important moment in the growth of a child, both for the family and the infant itself, and it can play a major role in the child’s future health. Throughout the years, various weaning modes have come in succession, the latest being baby-led weaning; the timing for introducing foods and the requirements of which sort of nutrient for weaning have also changed over time. Furthermore, the role played by nutrition, especially in the early stages of life, for the onset of later non-communicable disorders, such as diabetes, obesity or coeliac disease has also been increasingly highlighted.

Members of Italian Society of Gastroenterology, Hepathology and Pediatric Nutrition (SIGENP) and the Italian Society of Allergology and Pediatric Immunology (SIAIP) Emilia Romagna here propose a practical approach for pediatricians to deal with daily practice. The four main areas for discussion were weaning in relation with the onset of allergic diseases, coeliac disease, diabetes and metabolic syndrome, the nutrition requirements to take into account for assessing the diet of infants under one year of age and about the practice of baby-led weaning focusing on limits and benefits, respectively.

Intestinal microbiota succession and immunomodulatory consequences after introduction of Lactobacillus reuteri I5007 in neonatal piglets

Seventy-two, suckling piglets, obtained from 9 litters standardized to 8 piglets, were assigned to 1 of 3 treatments (n = 24) to compare short-term, early administration with intermittent, longer-term administration of Lactobacillus reuteri I5007. The treatments were a control (given a placebo of 0.1% peptone water from day 1 to 5) or treatments in which 1.7 × 10¹⁰ CFU L. reuteri was administrated either daily for 4 days starting on day 1 or every 4th day from day 1 to 17. Five piglets per treatment were killed at 3 time points (day 7, 14 and 21). Denaturing Gradient Electrophoresis of ileal digesta revealed an increase in the presence of L. reuteri I5007 and Clostridium lentocellum (on day 14 and 21) in the every 4th-day treatment and Actinobacillus porcinus (on day 7 and 14) in both L. reuteri treatments, while reducing the abundance of E. coli on day 21 in the every 4th-day treatment. Real-time qPCR of ileal digesta showed an increase in Bifidobacterium spp. on day 14 for both L. reuteri I5007 treatments. An increase in the concentration of lactic acid and a lower pH was observed in the first 4-day treatment on day 7 and the every 4^th day treatment on day 14. The relative abundance of mRNA for TGF-β was increased while that for IFN-γ was decreased in the mesenteric lymph nodes of piglets treated with L. reuteri every 4^th day. In conclusion, early intervention with L. reuteri increases the presence of beneficial bacteria and decreases the presence of undesirable microbes in the lower gastrointestinal tract. The changes appear to be mediated by altering the intestinal pH through lactic acid production resulting in favorable bacterial species colonization. A prolonged duration of treatment (i.e. every 4^th day) would appear to be superior to treatment only during the first 4 days.

Human colostrum oligosaccharides modulate major immunologic pathways of immature human intestine

The immature neonatal intestinal immune system hyperreacts to newly colonizing unfamiliar bacteria. The hypothesis that human milk oligosaccharides from colostrum (cHMOSs) can directly modulate the signaling pathways of the immature mucosa was tested. Modulation of cytokine immune signaling by HMOSs was measured ex vivo in intact immature (fetal) human intestinal mucosa. From the genes whose transcription was modulated by cHMOSs, Ingenuity Pathway Analysis identified networks controlling immune cell communication, intestinal mucosal immune system differentiation, and homeostasis. cHMOSs attenuate pathogen-associated molecular pattern-stimulated acute phase inflammatory cytokine protein levels (interleukin-8 (IL-8), IL-6, monocyte chemoattractant protein-1/2 and IL-1β), while elevating cytokines involved in tissue repair and homeostasis. In all, 3'-, 4-, and 6'-galactosyllactoses of cHMOSs account for specific immunomodulation of polyinosinic:polycytodylic acid-induced IL-8 levels. cHMOSs attenuate mucosal responses to surface inflammatory stimuli during early development, while enhancing signals that support maturation of the intestinal mucosal immune system.

Temporal changes and the effect of subtherapeutic concentrations of antibiotics in the gut microbiota of swine

The use of antibiotics in swine production for the purpose of growth promotion dates back to the 1950s. Despite this long history of use, the exact mechanism(s) responsible for the growth-promoting effects of antibiotics in swine remain largely unknown. It is believed, however, that growth promotion is due to antibiotics having a direct impact on the gut microbiota. In this study, the effect of two antibiotics on the swine gut microbiota over a 19-week monitoring period was investigated using Illumina-based sequencing. A shift in the relative abundance of several taxa and in 26 operational taxonomic units (OTUs) was observed in pigs fed subtherapeutic concentrations of tylosin (44-11 mg kg(-1) feed). Only minor alterations were noted with the administration of chlortetracycline at 5.5 mg kg(-1) feed. The most notable changes in the relative abundance of taxa and OTUs were noted between suckling piglets and postweaned pigs. Diversity was also reduced in the gut microbiota of suckling piglets as measured using the Shannon, Chao1, and phylogenetic diversity indices. These results show that the effect of antibiotics on the swine gut microbiota is variable based on dosage and duration and that the swine gut microbiota exhibits considerable resilience to long-term changes due to antibiotic perturbations.