Review on Preventive Measures to Reduce Post-Weaning Diarrhoea in Piglets

Nutrition strategies to control post-weaning diarrhea of piglets: From the perspective of feeds

Post-weaning diarrhea (PWD) is a globally significant threat to the swine industry. Historically, antibiotics as well as high doses of zinc oxide and copper sulfate have been commonly used to control PWD. However, the development of bacterial resistance and environmental pollution have created an interest in alternative strategies. In recent years, the research surrounding these alternative strategies and the mechanisms of piglet diarrhea has been continually updated. Mechanically, diarrhea in piglets is a result of an imbalance in intestinal fluid and electrolyte absorption and secretion. In general, enterotoxigenic Escherichia coli (ETEC) and diarrheal viruses are known to cause an imbalance in the absorption and secretion of intestinal fluids and electrolytes in piglets, resulting in diarrhea when Cl- secretion-driven fluid secretion surpasses absorptive capacity. From a perspective of feedstuffs, factors that contribute to imbalances in fluid absorption and secretion in the intestines of weaned piglets include high levels of crude protein (CP), stimulation by certain antigenic proteins, high acid-binding capacity (ABC), and contamination with deoxynivalenol (DON) in the diet. In response, efforts to reduce CP levels in diets, select feedstuffs with lower ABC values, and process feedstuffs using physical, chemical, and biological approaches are important strategies for alleviating PWD in piglets. Additionally, the diet supplementation with additives such as vitamins and natural products can also play a role in reducing the diarrhea incidence in weaned piglets. Here, we examine the mechanisms of absorption and secretion of intestinal fluids and electrolytes in piglets, summarize nutritional strategies to control PWD in piglets from the perspective of feeds, and provide new insights towards future research directions.

Dietary nutrition, intestinal microbiota dysbiosis and post-weaning diarrhea in piglets

Weaning is a critical transitional point in the life cycle of piglets. Early weaning can lead to post-weaning syndrome, destroy the intestinal barrier function and microbiota homeostasis, cause diarrhea and threaten the health of piglets. The nutritional components of milk and solid foods consumed by newborn animals can affect the diversity and structure of their intestinal microbiota, and regulate post-weaning diarrhea in piglets. Therefore, this paper reviews the effects and mechanisms of different nutrients, including protein, dietary fiber, dietary fatty acids and dietary electrolyte balance, on diarrhea and health of piglets by regulating intestinal function. Protein is an essential nutrient for the growth of piglets; however, excessive intake will cause many harmful effects, such as allergic reactions, intestinal barrier dysfunction and pathogenic growth, eventually aggravating piglet diarrhea. Dietary fiber is a nutrient that alleviates post-weaning diarrhea in piglets, which is related to its promotion of intestinal epithelial integrity, microbial homeostasis and the production of short-chain fatty acids. In addition, dietary fatty acids and dietary electrolyte balance can also facilitate the growth, function and health of piglets by regulating intestinal epithelial function, immune system and microbiota. Thus, a targeted control of dietary components to promote the establishment of a healthy bacterial community is a significant method for preventing nutritional diarrhea in weaned piglets.

Detection and Analysis of Antidiarrheal Genes and Immune Factors in Various Shanghai Pig Breeds

The aim of this study was to identify effective genetic markers for the Antigen Processing Associated Transporter 1 (TAP1), α (1,2) Fucosyltransferase 1 (FUT1), Natural Resistance Associated Macrophage Protein 1 (NRAMP1), Mucin 4 (MUC4) and Mucin 13 (MUC13) diarrhea-resistance genes in the local pig breeds, namely Shanghai white pigs, Fengjing pigs, Shawutou pigs, Meishan pigs and Pudong white pigs, to provide a reference for the characterization of local pig breed resources in Shanghai. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLR) and sequence sequencing were applied to analyze the polymorphisms of the above genes and to explore the effects on the immunity of Shanghai local pig breeds in conjunction with some immunity factors. The results showed that both TAP1 and MUC4 genes had antidiarrheal genotype GG in the five pig breeds, AG and GG genotypes of the FUT1 gene were detected in Pudong white pigs, AA antidiarrheal genes of the NRAMP1 gene were detected in Meishan pigs, the AB type of the NRAMP1 gene was detected in Pudong white pigs, and antidiarrheal genotype GG of the MUC13 gene was only detected in Shanghai white pigs. The MUC13 antidiarrhea genotype GG was only detected in Shanghai white pigs. The TAP1 gene was moderately polymorphic in Shanghai white pigs, Fengjing pigs, Shawutou pigs, Meishan pigs and Pudong white pigs, among which TAP1 in Shanghai white pigs and Shawutou pigs did not satisfy the Hardy-Weinberg equilibrium. The FUT1 gene of Pudong white pigs was in a state of low polymorphism. NRAMP1 of Meishan pigs and Pudong white pigs was in a state of moderate polymorphism, which did not satisfy the Hardy-Weinberg equilibrium. The MUC4 genes of Shanghai white pigs and Pudong white pigs were in a state of low polymorphism, and the MUC4 genes of Fengjing pigs and Shawutou pigs were in a state of moderate polymorphism, and the MUC4 genes of Fengjing pigs and Pudong white pigs did not satisfy the Hardy-Weinberg equilibrium. The MUC13 gene of Shanghai white pigs and Pudong white pigs was in a state of moderate polymorphism. Meishan pigs had higher levels of IL-2, IL-10, IgG and TNF-α, and Pudong white pigs had higher levels of IL-12 than the other pigs. The level of interleukin 12 (IL-12) was significantly higher in the AA genotype of the MUC13 gene of Shanghai white pigs than in the AG genotype. The indicator of tumor necrosis factor alpha (TNF-α) in the AA genotype of the TAP1 gene of Fengjing pigs was significantly higher than that of the GG and AG genotypes. The indicator of IL-12 in the AG genotype of the Shawutou pig TAP1 gene was significantly higher than that of the GG genotype. The level of TNF-α in the AA genotype of the NRAMP1 gene of Meishan pigs was markedly higher than that of the AB genotype. The IL-2 level of the AG type of the FUT1 gene was obviously higher than that of the GG type of Pudong white pigs, the IL-2 level of the AA type of the MUC4 gene was dramatically higher than that of the AG type, and the IgG level of the GG type of the MUC13 gene was apparently higher than that of the AG type. The results of this study are of great significance in guiding the antidiarrhea breeding and molecular selection of Shanghai white pigs, Fengjing pigs, Shawutou pigs, Meishan pigs and Pudong white pigs and laying the foundation for future antidiarrhea breeding of various local pig breeds in Shanghai.

Gut microbiome and resistome characterization of pigs treated with commonly used post-weaning diarrhea treatments

BACKGROUND

The global burden of antimicrobial resistance demands additional measures to ensure the sustainable and conscious use of antimicrobials. For the swine industry, the post-weaning period is critical and for many years, antimicrobials have been the most effective strategy to control and treat post-weaning related infections. Among them, post-weaning diarrhea causes vast economic losses, as it severely compromises piglets' health and growth performance. In this study, 210 piglets were transferred from a farm with recurrent cases of post-weaning diarrhea to an experimental farm and divided into six different treatment groups to determine the effect of the different treatments on the growth performance and survival, the microbiome, and the resistome in a cross-sectional and longitudinal study. The different treatments included antimicrobials trimethoprim/sulfamethoxazole, colistin, and gentamicin, an oral commercial vaccine, a control with water acidification, and an untreated control. An extra group remained at the farm of origin following the implemented amoxicillin routine treatment. A total of 280 fecal samples from pigs at four different sampling times were selected for metagenomics: before weaning-treatment at the farm of origin, and three days, two weeks, and four weeks post-treatment.

RESULTS

The control group with water acidification showed a reduced death risk in the survival analyses and non-significant differences in average daily weight gain in comparison to the antibiotic-treated groups. However, the growth-promoting effect among antibiotic-treated groups was demonstrated when comparing against the untreated control group at the experimental farm. After four weeks of treatment, diversity indexes revealed significantly decreased diversity for the untreated control and the group that remained at the farm of origin treated with amoxicillin. For this last group, impaired microbial diversity could be related to the continuous amoxicillin treatment carried out at the farm. Analysis of the resistome showed that both gentamicin and amoxicillin treatments significantly contributed to the emergence of resistance, while trimethoprim/sulphonamide and colistin did not, suggesting that different treatments contribute differently to the emergence of resistance.

CONCLUSIONS

Overall, this shotgun longitudinal metagenomics analysis demonstrates that non-antibiotic alternatives, such as water acidification, can contribute to reducing the emergence of antimicrobial resistance without compromising pig growth performance and gut microbiome.

Colonization factors of human and animal-specific enterotoxigenic Escherichia coli (ETEC)

Colonization factors (CFs) are major virulence factors of enterotoxigenic Escherichia coli (ETEC). This pathogen is among the most common causes of bacterial diarrhea in children in low- and middle-income countries, travelers, and livestock. CFs are major candidate antigens in vaccines under development as preventive measures against ETEC infections in humans and livestock. Recent molecular studies have indicated that newly identified CFs on human ETEC are closely related to animal ETEC CFs. Increased knowledge of pathogenic mechanisms, immunogenicity, regulation, and expression of ETEC CFs, as well as the possible spread of animal ETEC to humans, may facilitate the future development of ETEC vaccines for humans and animals. Here, we present an updated review of CFs in ETEC.

In vitro and in vivo fermentation models to study the function of dietary fiber in pig nutrition

The importance of dietary fiber (DF) in animal diets is increasing with the advancement of nutritional research. DF is fermented by gut microbiota to produce metabolites, which are important in improving intestinal health. This review is a systematic review of DF in pig nutrition using in vitro and in vivo models. The fermentation characteristics of DF and the metabolic mechanisms of its metabolites were summarized in an in vitro model, and it was pointed out that SCFAs and gases are the important metabolites connecting DF, gut microbiota, and intestinal health, and they play a key role in intestinal health. At the same time, some information about host-microbe interactions could have been improved through traditional animal in vivo models, and the most direct feedback on nutrients was generated, confirming the beneficial effects of DF on sow reproductive performance, piglet intestinal health, and growing pork quality. Finally, the advantages and disadvantages of different fermentation models were compared. In future studies, it is necessary to flexibly combine in vivo and in vitro fermentation models to profoundly investigate the mechanism of DF on the organism in order to promote the development of precision nutrition tools and to provide a scientific basis for the in-depth and rational utilization of DF in animal husbandry. KEY POINTS: • The fermentation characteristics of dietary fiber in vitro models were reviewed. • Metabolic pathways of metabolites and their roles in the intestine were reviewed. • The role of dietary fiber in pigs at different stages was reviewed.

Survey on resistance occurrence for F4+ and F18+ enterotoxigenic Escherichia coli (ETEC) among pigs reared in Central Italy regions

Porcine Post Weaning Diarrhoea (PWD) is one of the most important swine disease worldwide, caused by Enterotoxigenic Escherichia coli (ETEC) strains able to provoke management, welfare and sanitary issues. ETEC is determined by proteinaceous surface appendages. Numerous studies conducted by now in pigs have demonstrated, at the enterocytes level, that, the genes mucin 4 (MUC4) and fucosyltransferase (FUT1), coding for ETEC F4 and F18 receptors respectively, can be carriers of single nucleotide polymorphisms (SNPs) associated with natural resistance/susceptibility to PWD. The latter aspect was investigated in this study, evaluating the SNPs of the MUC4 and FUT1 genes in slaughtered pigs reared for the most in Central Italy. Genomic DNA was extracted from 362 swine diaphragmatic samples and then was subjected to the detection of known polymorphisms on MUC4 and FUT1candidate target genes by PCR-RFLP. Some of the identified SNPs were confirmed by sequencing analysis. Animals carrying the SNPs associated with resistance were 11% and 86% for the FUT1 and MUC4 genes respectively. Therefore, it can be assumed that the investigated animals may be an important resource and reservoir of favorable genetic traits for the breeding of pigs resistant to enterotoxigenic E.coli F4 variant.

Effect of a probiotic and an antibiotic on the mobilome of the porcine microbiota

Introduction: To consider the growing health issues caused by antibiotic resistance from a "one health" perspective, the contribution of meat production needs to be addressed. While antibiotic resistance is naturally present in microbial communities, the treatment of farm animals with antibiotics causes an increase in antibiotic resistance genes (ARG) in the gut microbiome. Pigs are among the most prevalent animals in agriculture; therefore, reducing the prevalence of antibiotic-resistant bacteria in the pig gut microbiome could reduce the spread of antibiotic resistance. Probiotics are often studied as a way to modulate the microbiome and are, therefore, an interesting way to potentially decrease antibiotic resistance. Methods: To assess the efficacy of a probiotic to reduce the prevalence of ARGs in the pig microbiome, six pigs received either treatment with antibiotics (tylvalosin), probiotics (Pediococcus acidilactici MA18/5M; Biopower® PA), or a combination of both. Their faeces and ileal digesta were collected and DNA was extracted for whole genome shotgun sequencing. The reads were compared with taxonomy and ARG databases to identify the taxa and resistance genes in the samples. Results: The results showed that the ARG profiles in the faeces of the antibiotic and combination treatments were similar, and both were different from the profiles of the probiotic treatment (p < 0.05). The effects of the treatments were different in the digesta and faeces. Many macrolide resistance genes were detected in a higher proportion in the microbiome of the pigs treated with antibiotics or the combination of probiotics and antibiotics. Resistance-carrying conjugative plasmids and horizontal transfer genes were also amplified in faeces samples for the antibiotic and combined treatments. There was no effect of treatment on the short chain fatty acid content in the digesta or the faeces. Conclusion: There is no positive effect of adding probiotics to an antibiotic treatment when these treatments are administered simultaneously.

The cotton swab method: an accurate and less invasive way to assess fecal consistency in weaned pigs

BACKGROUND

Researchers and pig veterinarians are interested in assessing pigs' fecal consistency. This study developed a standardized protocol and scale for the cotton swab method, which is a way of assessing the fecal consistency in pigs. The accuracy of the cotton swab method was evaluated in weaned pigs using fecal dry-matter analysis as a golden standard. The study also proposed fecal dry-matter percentage thresholds for the categorization of fecal consistency on a four-point scale.

RESULTS

The thresholds of 10.3%, 16.6%, and 21.9% fecal dry-matter were suggested for categorization of the consistency of fecal samples on a four-point scale. The accuracy of the cotton swab method was high. The agreement to the four-point fecal consistency score derived from the fecal dry-matter percentage was almost perfect (weighted Gwet's agreement coefficient = 0.87 [95% confidence interval: 0.84; 0.91]). The cotton swab method had a sensitivity of 85.0% (95% confidence interval: 76.5; 91.4) and a specificity of 95.2% (95% confidence interval: 92.0; 97.3) when used to diagnose whether pigs had diarrhea or not. For non-diarrheic pigs, the method almost always (n = 287/289) required less handling than the collection of a fecal sample by digital rectal manipulation.

CONCLUSION

The cotton swab method is an accurate way to assess fecal consistency in pigs, both on a four-point scale and as a dichotomous diarrhea score. The method is quick to perform and less invasive than methods relying on the collection of fecal samples. New fecal dry-matter thresholds between feces of different consistencies were proposed.

Quercetin Improves Barrier Properties in Porcine Small Intestine but Not in Peyer's Patches

Peyer's patches (PPs) are part of the gut-associated lymphatic tissue (GALT) and represent the first line of the intestinal immunological defense. They consist of follicles with lymphocytes and an overlying subepithelial dome with dendritic cells and macrophages, and they are covered by the follicle-associated epithelium (FAE). A sealed paracellular pathway in the FAE is crucial for the controlled uptake of luminal antigens. Quercetin is the most abundant plant flavonoid and has a barrier-strengthening effect on tight junctions (TJs), a protein complex that regulates the paracellular pathway. In this study, we aimed to analyze the effect of quercetin on porcine PPs and the surrounding villus epithelium (VE). We incubated both tissue types for 4 h in Ussing chambers, recorded the transepithelial electrical resistance (TEER), and measured the unidirectional tracer flux of [3H]-mannitol. Subsequently, we analyzed the expression, protein amount, and localization of three TJ proteins, claudin 1, claudin 2, and claudin 4. In the PPs, we could not detect an effect of quercetin after 4 h, neither on TEER nor on the [3H]-mannitol flux. In the VE, quercetin led to a higher TEER value, while the [3H]-mannitol flux was unchanged. The pore-forming claudin 2 was decreased while the barrier-forming claudin 4 was increased and the expression was upregulated. Claudin 1 was unchanged and all claudins could be located in the paracellular membrane by immunofluorescence microscopy. Our study shows the barrier-strengthening effect of quercetin in porcine VE by claudin 4 upregulation and a claudin 2 decrease. Moreover, it underlines the different barrier properties of PPs compared to the VE.

Effect of dietary tall oil fatty acids and hydrolysed yeast in SNP2-positive and SNP2-negative piglets challenged with F4 enterotoxigenic Escherichia coli

Reduction of post-weaning diarrhoea caused by ETEC is a principal objective in pig farming in terms of welfare benefits. This study determined the effects of genetic susceptibility and dietary strategies targeting inflammation and fimbriae adherence on F4-ETEC shedding and diarrhoea in weaned piglets in an experimental challenge model. A DNA marker test targeting single nucleotide polymorphism 2 (SNP2) identified piglets as heterozygous (SNP2+, susceptible) or homozygous (SNP2-, resistant) to developing F4ac-ETEC diarrhoea. A total of 50 piglets, 25 SNP2+ and 25 SNP2-, were weaned at 30 days of age and equally distributed to different treatments (n = 10): Positive control (PC): piglets fed with a negative control diet and provided with colistin via drinking water; Negative control (NC): piglets fed with a negative control diet; Tall oil fatty acids (TOFA): piglets fed with a negative control diet + 1.0 g TOFA/kg feed; Yeast hydrolysate (YH): piglets fed with a negative control diet + 1.5 g YH/kg feed derived from Saccharomyces cerevisiae; and Combination (COM): piglets fed with a negative control diet + 1.0 g TOFA and 1.5 g YH/kg feed. On day 10 post-weaning, all piglets were infected with F4-ETEC by oral administration. Piglets fed with PC, TOFA, YH or COM had a lower faecal shedding of F4-ETEC than NC piglets (P < 0.001), which was also shorter in duration for PC and TOFA piglets than for NC piglets (P < 0.001). Piglets in PC, TOFA, YH and COM had a shorter diarrhoea duration versus NC when classified as SNP2+ (P = 0.02). Furthermore, PC, TOFA and YH piglets grew more than NC and COM piglets in the initial post-inoculation period (P < 0.001). In addition, the level of faecal F4-ETEC shedding and the percentage of pigs that developed F4-ETEC diarrhoea (72 vs. 32%, P < 0.01) following infection were higher, and the duration of F4-ETEC diarrhoea longer (2.6 vs. 0.6 days, P < 0.001), in SNP2+ piglets than in SNP2- piglets, and led to reduced growth performance (P = 0.03). In conclusion, piglets fed with TOFA, YH or their combination, irrespective of their SNP2 status, are more resilient to F4-ETEC infection. Moreover, SNP2+ piglets show a higher level of F4-ETEC shedding and diarrhoea prevalence than SNP2- piglets, confirming an association between SNP2 and F4ac-ETEC susceptibility.

Evaluation of a microencapsulated form of zinc oxide on weanling pig growth performance, fecal zinc excretion, and small intestinal morphology

A total of 300 pigs (DNA 200 × 400; initially 6.0 ± 0.08 kg body weight [BW]) were used in a 42-d study to evaluate a microencapsulated form of zinc oxide. At weaning, pigs were randomly allocated to pens, and pens were randomly assigned to dietary treatments with 5 pigs per pen and 12 pens per treatment. Dietary treatments were 1) negative control (CON; standard nursery diet containing 110 ppm Zn in the form of zinc sulfate from trace mineral premix); 2) control diet with 400 ppm added Zn from ZnO included in phases 1 and 2 (Low-ZnO); 3) control diet with 3,000 ppm added Zn from ZnO included in phase 1 and 2,000 ppm added Zn from ZnO included in phase 2 (High-ZnO); 4) control diet with 400 ppm added Zn from microencapsulated ZnO included in phases 1 and 2 (Low-MZnO; Vetagro S.p.A., Reggio Emilia, Italy); 5) control diet with 3,000 ppm added Zn from microencapsulated ZnO in phase 1 and 2,000 ppm added Zn from microencapsulated ZnO in phase 2 (high-MZnO; Vetagro S.p.A., Reggio Emilia, Italy). On days 10 and 28, fecal samples from 2 pigs per pen were collected for fecal Zn concentrations, and on day 28, 30 pigs (n = 6) were euthanized, and small intestinal tissues were collected to evaluate morphology. For the entire treatment period (days 0 to 28) there was no evidence of differences in average daily gain (ADG), average daily feed intake (ADFI), or G:F (P > 0.05). During the common phase 3 (days 28 to 42) pigs fed the negative control, High-MZnO, or Low-MZnO had improved (P < 0.0001) ADG and ADFI compared to pigs fed High- or Low-ZnO. For the entire experiment (days 0 to 42), pigs fed Low-ZnO or High-ZnO had reduced (P < 0.0001) ADG compared to those fed the negative control. A significant treatment × day interaction (P = 0.04) was observed for fecal Zn concentrations, where the level of Zn excreted in the feces was dependent on the sampling day in pigs fed a low level of ZnO or low level of microencapsulated ZnO. There was no evidence (P > 0.05) that small intestinal morphology differed significantly between treatments. In summary, feeding a microencapsulated form of ZnO did not alter piglet growth performance during the treatment period. Pigs fed a low level of ZnO or microencapsulated ZnO had reduced fecal Zn excretion by the end of the feeding period, but no significant impacts were observed on piglet small intestinal morphology.

Nutritional Strategies to Mitigate Post-Weaning Challenges in Pigs: A Focus on Glucans, Vitamin D, and Selenium

This review examines the challenges faced by the pig industry, with a specific focus on improving the health and growth of weaned pigs. It emphasizes the immediate necessity of investigating alternative approaches to managing pig nutrition and health due to restrictions on the use of antibiotics and the prohibition of zinc oxide in weaned pig diets. The weaning phase is identified as a critical stage in piglet development, characterized by stressors that affect their gastrointestinal health, immune responses, and overall physiology. The primary challenge during weaning arises from transitioning piglets from a digestible milk-based diet to a less digestible cereal-based feed, causing nutritional stress. This manifests as reduced feed intake, leading to gastrointestinal disturbances, intestinal inflammation, and adverse effects on intestinal structure and microbiota. To address these challenges and optimize piglet development, various nutritional strategies have been explored. Notably, glucans, particularly β-glucans from fungi, cereals, algae, and yeast, show promise in alleviating weaning-related issues. Furthermore, it is important to highlight the critical roles played by Vitamin D and selenium in piglet nutrition. These essential nutrients can be sourced naturally from enriched mushrooms that are specifically enriched with Vitamin D and selenium, providing a sustainable dietary option. In conclusion, effective nutritional strategies, including glucans, Vitamin D, selenium, and enriched mushrooms, are beneficial for addressing weaning-related challenges.

Effects of dietary traditional Chinese medicine residues on growth performance, intestinal health and gut microbiota compositions in weaned piglets

Weaning stress can induce diarrhea, intestinal damage and flora disorder of piglets, leading to slow growth and even death of piglets. Traditional Chinese medicine residue contains a variety of active ingredients and nutrients, and its resource utilization has always been a headache. Therefore, we aimed to investigate the effects of traditional Chinese medicine residues (Xiasangju, composed of prunellae spica, mulberry leaves, and chrysanthemum indici flos) on growth performance, diarrhea, immune function, and intestinal health in weaned piglets. Forty-eight healthy Duroc× Landrace × Yorkshire castrated males weaned aged 21 days with similar body conditions were randomly divided into 6 groups with eight replicates of one piglet. The control group was fed a basal diet, the antibiotic control group was supplemented with 75 mg/kg chlortetracycline, and the residue treatment groups were supplemented with 0.5%, 1.0%, 2.0% and 4.0% Xiasangju residues. The results showed that dietary Xiasangju residues significantly reduced the average daily feed intake, but reduced the diarrhea score (P < 0.05). The 1.0% and 2.0% Xiasangju residues significantly increased the serum IgM content of piglets, and the 0.5%, 1.0%, 2.0% and 4.0% Xiasangju residues significantly increased the serum IgG content, while the 1.0%, 2.0% and 4.0% Xiasangju residues significantly increased the sIgA content of ileal contents (P < 0.05). Dietary Xiasangju residues significantly increased the villus height and the number of villus goblet cells in the jejunum and ileum, and significantly decreased the crypt depth (P<0.05). The relative mRNA expression of IL-10 in the ileum was significantly increased in the 1% and 2% Xiasangju residues supplemented groups (P < 0.05), while IL-1β in the ileum was downregulated (P < 0.05). Xiasangju residues improved the gut tight barrier, as evidenced by the enhanced expression of Occludin and ZO-1 in the jejunum and ileum. The diets with 1% Xiasangju residues significantly increased the relative abundance of Lactobacillus johnsonii, and 2% and 4% Xiasangju residues significantly increased the relative abundance of Weissella jogaeotgali (P < 0.05). Dietary supplementation with 0.5%, 1.0%, 2% and 4% with Xiasangju residues significantly decreased the relative abundance of Escherichia coli and Treponema porcinum (P < 0.05). In summary, dietary supplementation with Xiasangju residues improves intestinal health and gut microbiota in weaned piglets.

New Perspective for Macroalgae-Based Animal Feeding in the Context of Challenging Sustainable Food Production

Food production is facing challenging times due to the pandemic, and climate change. With production expected to double by 2050, there is a need for a new paradigm in sustainable animal feed supply. Seaweeds offer a highly valuable opportunity in this regard. Seaweeds are classified into three categories: brown (Phaeophyceae), red (Rhodophyceae), and green (Chlorophyceae). While they have traditionally been used in aquafeed, their demand in the feed market is growing, parallelly increasing according to the food demand. Additionally, seaweeds are being promoted for their nutritional benefits, which contribute to the health, growth, and performance of animals intended for human consumption. Moreover, seaweeds contain biologically active compounds such as polyunsaturated fatty acids, antioxidants (polyphenols), and pigments (chlorophylls and carotenoids), which possess beneficial properties, including antibacterial, antifungal, antiviral, antioxidant, and anti-inflammatory effects and act as prebiotics. This review offers a new perspective on the valorization of macroalgae biomass due to their nutritional profile and bioactive components, which have the potential to play a crucial role in animal growth and making possible new sources of healthy food ingredients.

Selected Nutrition and Management Strategies in Suckling Pigs to Improve Post-Weaning Outcomes

Weaning is a critical period in a pig's life. Piglets are confronted with abrupt changes to their physical and social environment, as well as management and nutritional changes. Weaning has always been associated with a growth check and is frequently accompanied by post-weaning diarrhoea in piglets. However, rapid increases in litter size in the last decade have increased within-litter piglet weight variation, with piglets now generally lighter at weaning, making the challenges associated with weaning even greater. Many interventions can be employed during the suckling period to ease the weaning transition for piglets. Pre-weaning strategies such as supervised farrowing (assistance with suckling and oxytocin provision), the provision of pain relief to sows around farrowing, split-suckling, early oral supplementation with glucose, bovine colostrum, faecal microbiota transplantation, feed additives and solid and liquid creep feeding (milk and liquid feed) have all been investigated. The objective of these strategies is to stimulate earlier maturation of the digestive tract, improve immunity, reduce latency to the first feed post-weaning and increase early post-weaning feed intake and growth. This review focuses in particular on: (1) pain relief provision to sows around farrowing, (2)split-suckling of piglets, (3) pre-weaning provision of supplementary milk and/or liquid feed, (4) other strategies to stimulate earlier enzyme production (e.g., enzyme supplementation), (5) other nutritional strategies to promote improved gut structure and function (e.g., L-glutamine supplementation), and (6) other strategies to modulate gut microbiota (e.g., probiotics and prebiotics). Correctly implementing these strategies can, not only increase post-weaning growth and reduce mortality, but also maximise lifetime growth in pigs.

Liquid fermented cereals with added Pediococcus acidilactici did not reduce post-weaning diarrhea in pigs - an Escherichia coli challenge study

The effect of feeding fermented liquid feed (FLF) with added Pediococcus acidilactici to weaning piglets challenged with enterotoxigenic Escherichia coli (ETEC) F4 on aspects of diarrhea, performance, immune responses, and intestinal epithelial barrier function was investigated. A total of 46 weaners (weaning at 27-30 days of age) were assigned to four treatments: (1) Non-challenged and dry feed (Non-Dry); (2) Challenged and dry feed (Ch-Dry); (3) Non-challenged and FLF (Non-Ferm); (4) Challenged and FLF (Ch-Ferm). All groups received the same feed, either dry (Non-Dry and Ch-Dry), or in liquid form (Non-Ferm and Ch-Ferm) in which the cereals with added P. acidilactici (10⁶ CFU/g cereals) had been fermented for 24 h at 30°C. On day 1 and 2 post weaning, Ch-Dry and Ch-Ferm were orally inoculated with 5 mL × 10⁹ CFU ETEC F4/mL, whereas the Non-Dry and Non-Ferm received the same amount of saline. Fecal samples and blood samples were collected through the study period. The microbial composition, concentration of microbial metabolites and nutrient composition indicated that the quality of the FLF was high. In the first week, ADFI of both non-challenged groups was significantly higher (p < 0.05) than that of the Ch-Ferm group. The two challenged groups had higher fecal levels of FaeG gene (ETEC F4 fimbriae) from day 2 to 6 post weaning (p < 0.01), and higher risk of having ETEC F4 present in feces from day 3 to 5 post weaning (p < 0.05) compared to non-challenged groups, indicating the validity of the ETEC challenge model. Generally, ADG of the two groups fed FLF were numerically higher than those fed dry feed. Neither challenge nor FLF affected diarrhea. No significant differences were measured between Ch-Ferm and Ch-Dry regarding the level of plasma haptoglobin and C-reactive protein, hematological parameters or parameters related to epithelial barrier. The data indicated a low level of infection caused by the ETEC challenge, while recovery from weaning stress could be observed. The study showed that a strategy like this can be a way of providing a high level of probiotics to pigs by allowing their proliferation during fermentation.

Antibacterial plant combinations prevent postweaning diarrhea in organically raised piglets challenged with enterotoxigenic Escherichia coli F18

Antibiotics and zinc oxide restrictions encourage the search for alternatives to combat intestinal pathogens, including enterotoxigenic Escherichia coli (ETEC), a major cause of postweaning diarrhea (PWD) in pigs. PWD causes important economic losses for conventional and organic farming. This study investigated the effect of dietary supplementation with garlic and apple pomace or blackcurrant on infection indicators and the fecal microbiota of organic-raised piglets challenged with ETEC-F18. For 21 days, 32 piglets (7-weeks-old) were randomly assigned to one of four groups: non-challenge (NC); ETEC-challenged (PC); ETEC-challenged receiving garlic and apple pomace (3 + 3%; GA); ETEC-challenged receiving garlic and blackcurrant (3 + 3%; GB). ETEC-F18 was administered (8 mL; 109 CFU/ml) on days 1 and 2 postweaning. The 1st week, PC had lower average daily gain than those in the NC, GA, and GB groups (P &lt; 0.05). NC pigs showed neither ETEC-F18 shedding nor signs of diarrhea. The PC group had higher diarrhea incidence and lower fecal dry matter than NC (≈5–10 days; 95% sEBCI). The GA and GB groups showed reduced ETEC-F18 and fedA gene shedding, higher fecal dry matter, and lower diarrhea incidence than the PC (≈5–9 days; 95% sEBCI). The NC, GA, and GB had normal hematology values during most of the study, whereas the PC had increased (P &lt; 0.05) red blood cells, hemoglobin, and hematocrit on day 7. Haptoglobin and pig-MAP increased in all groups, peaking on day 7, but PC showed the greatest increase (P &lt; 0.05). The fecal microbiota of PC pigs had reduced α-diversity (day 7; P &lt; 0.05) and higher volatility (days 3–14; P &lt; 0.05). Escherichia, Campylobacter, and Erysipelothrix were more abundant in the PC than in the NC, GB, and GA groups (log2FC &gt; 2; P &lt; 0.05), whereas Catenibacterium, Dialister, and Mitsoukella were more abundant in the NC, GB, and GA than in the PC group (log2FC &gt; 2; P &lt; 0.05). Prevotella and Lactobacillus were more abundant in the GB group (log2FC &gt; 2, P &lt; 0.05). In conclusion, dietary supplementation of GA and GB limited ETEC proliferation, reduced PWD, and beneficially impacted the fecal microbiota's diversity, composition, and stability.

Feed additives of bacterial origin as an immunoprotective or imunostimulating factor

Since January 2006 when using antibiotics as growth promoters in animal feed have been banned scientists are looking for the best resolution to apply alternative substances. Extensive research into the health-promoting properties of probiotics and prebiotics has led to significant interest in the mechanisms of action of the combined administration of these feed additives as a synbiotic. Subsequent research has led to the development of new products. Among the most important health benefits of additives are, inhibiting the growth of pathogenic bacteria in the GI tract, maintenance of homeostasis, treatment of inflammatory bowel diseases, and increase in immunity. Specific immunomodulatory mechanisms of action are not well understood and the effect is not always positive, though there are no reports of adverse effects of these substances found in the literature. For this reason, research is still being conducted on their proper application. However, due to the difficulties of carrying out research on humans, evidence of the beneficial effect of these additives comes mainly from experiments on animals. The objective of the present work was to assess the effect of probiotics, prebiotics, and synbiotics, as well as new additives including postbiotics, proteobiotics, nutribiotics, and pharmabiotics, on specific immunomodulatory mechanisms of action, increase in immunity, the reduction of a broad spectrum of diseases.

Effects of Exposure to Low Zearalenone Concentrations Close to the EU Recommended Value on Weaned Piglets’ Colon

Pigs are the most sensitive animal to zearalenone (ZEN) contamination, especially after weaning, with acute deleterious effects on different health parameters. Although recommendations not to exceed 100 µg/kg in piglets feed exists (2006/576/EC), there are no clear regulations concerning the maximum limit in feed for piglets, which means that more investigations are necessary to establish a guidance value. Due to these reasons, the present study aims to investigate if ZEN, at a concentration lower than the EC recommendation for piglets, might affect the microbiota or induce changes in SCFA synthesis and can trigger modifications of nutritional, physiological, and immunological markers in the colon (intestinal integrity through junction protein analysis and local immunity through IgA production). Consequently, the effect of two concentrations of zearalenone were tested, one below the limit recommended by the EC (75 µg/kg) and a higher one (290 µg/kg) for comparison reasons. Although exposure to contaminated feed with 75 µg ZEN/kg feed did not significantly affect the observed parameters, the 290 µg/kg feed altered several microbiota population abundances and the secretory IgA levels. The obtained results contribute to a better understanding of the adverse effects that ZEN can have in the colon of young pigs in a dose-dependent manner.

Differential Impacts of Cereal and Protein Sources Fed to Pigs after Weaning on Diarrhoea and Faecal Shedding of Escherichia coli, Production, and Total Tract Apparent Digestibility

Different cereal types, in combination with different protein sources, are fed to pigs after weaning, but their interactions and possible implications are not well researched. In this study, 84 male weaned piglets were used in a 21-day feeding trial to investigate the effects of feeding either medium-grain or long-grain extruded rice or wheat, in a factorial combination with protein sources of either vegetable or animal origin, on postweaning performance, shedding of β-haemolytic Escherichia coli, and the coefficient of total tract apparent digestibility (CTTAD). Pigs fed either rice type performed the same (p > 0.05) as wheat-fed pigs after weaning. The use of vegetable protein sources reduced growth rate (p < 0.001) and feed intake (p = 0.007) and deteriorated the feed conversion ratio (p = 0.028) in weeks two and three compared to pigs fed animal protein sources. The number of antibiotic treatments given for clinical diarrhoea was similar (p > 0.05). However, the faecal E. coli score showed a trend for the main effect of protein source, with pigs fed animal proteins showing a higher E. coli score than pigs fed vegetable proteins (0.63 vs. 0.43, p = 0.057). There was also a tendency for an interaction (p = 0.069) between cereal type and protein source (p = 0.069), with this difference being associated with a greater faecal score in pigs fed diets with long-grain rice plus animal proteins and wheat plus animal proteins. Significant interactions occurred for the CTTAD when assessed in week three. In general, pigs fed diets with medium-grain rice or long-grain rice with animal proteins had a higher (p < 0.001) CTTAD for dietary components than pigs fed all other diets, and vegetable proteins depressed (p < 0.001) CTTAD compared to animal proteins (main effect of protein: p < 0.001). In summary, pigs tolerated the extruded rice-based diets well and performed equivalently to pigs fed wheat as the sole cereal, and the use of vegetable proteins decreased the E. coli score.

Study on the mechanism of Wumei San in treating piglet diarrhea using network pharmacology and molecular docking

Wumei San (WMS) is a traditional Chinese medicine that has been widely applied in the treatment of piglet diarrhea (PD). However, the mechanism of WMS in PD has not been investigated. In this study, the main active compounds of WMS and the target proteins were obtained from the Traditional Chinese Medicine Systematic Pharmacology, PubChem, and SwissTargetPrediction databases. The molecular targets of PD were identified using GeneCards, OMIM, and NCBI databases. The common targets of WMS and PD were screened out and converted into UniProt gene symbols. PD-related target genes were constructed into a protein-protein interaction network, which was further analyzed by the STRING online database. Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed to construct the component-target gene-disease network. Molecular docking was then used to examine the relationship between the core compounds and proteins. As a result, a total of 32 active compounds and 638 target genes of WMS were identified, and a WMS-compound-target network was successfully constructed. Through network pharmacology analysis, 14 core compounds in WMS that showed an effect on PD were identified. The targets revealed by GO and KEGG enrichment analysis were associated with the AGE-RAGE signaling pathway, PI3K-Akt signaling pathway, TNF signaling pathway, NOD-like receptor signaling pathway, IL-17 signaling pathway, and other pathways and physiological processes. Molecular docking analysis revealed that the active compounds in WMS spontaneously bind to their targets. The results indicated that WMS may regulate the local immune response and inflammatory factors mainly through the TNF signaling pathway, IL-17 signaling pathway, and other pathways. WMS is a promising treatment strategy for PD. This study provides new insights into the potential mechanism of WMS in PD.