Dietary vitamin D supplementation attenuates immune responses of pigs challenged with rotavirus potentially through the retinoic acid-inducible gene I signalling pathway

Effects of dietary supplementation levels of vitamin A and vitamin D3 on growth performance, jejunal function, and tibia development in goslings from 1 to 28 days of age

This study explored the interaction effects of dietary Vitamin A (VA) and Vitamin D3 (VD3) on growth performance, jejunal function, and tibia development in goslings, aiming to identify any synergistic outcomes that may reshape nutritional strategies for geese production. A total of 540 one-day-old male Jiangnan White goslings with similar body weight (82 ± 5 g) were randomly assigned into 9 treatments with five replicate pens per treatment and 12 birds per pen. The bird trial employed a 3 × 3, two-factorial treatment with three levels of VA (5000, 7000, and 9000 IU/kg) and three levels of VD3 (1000, 1500, and 2000 IU/kg) from one to 28 days of age. Main effects analysis indicated that birds fed 7000 IU/kg VA exhibited the highest ADG, BW, jejunal maltase activity and IL-10 content (P < 0.05), while 9000 IU/kg VA had the highest SOD activity and content of IL-6 and TNF-α in jejunal mucosa (P < 0.05). Both 7000 IU/kg or 9000 IU/kg VA increased the jejunal IL-1β content, relative expression of tight junction protein 1 (TJP1) mRNA, tibia defatted weight and ash weight (P < 0.05). Birds fed 2000 IU/kg VD3 exhibited the highest ADFI, while both 1500 or 2000 IU/kg VD3 increased jejunal maltase activity, and tibia ash content (P < 0.05). An interaction between VA and VD3 on ADFI, F/G, jejunal maltase activity, mucosal immune factors (IL-1β, IL-6, IL-10, TNF-α), tibia ash content, and bone morphogenetic protein-2 (BMP-2) expression. A simple effects analysis revealed that at a 5000 IU/kg VA, adding 1000 IU/kg VD3 decreased IL-1β, IL-6, TNF-α (P < 0.05). At a 7000 IU/kg VA, adding 1500 or 2000 IU/kg VD3 decreased TNF-α, and increased jejunal maltase activity(P < 0.05). At a 9000 IU/kg VA, adding 1000 IU/kg VD3 decreased ADFI, F/G, jejunal maltase activity, tibia ash, and BMP-2, while IL-1β, IL-6, and TNF-α increased (P < 0.05). At a 9000 IU/kg VA, adding 2000 IU/kg VD3 increased IL-10 (P < 0.05). At a 1000 IU/kg VD3, adding 5000 IU/kg VA increased F/G, jejunal maltase activity and IL-10, while decreased IL-1β, IL-6, TNF-α (P < 0.05), and adding 9000 IU/kg VA decreased tibia ash and BMP-2 (P < 0.05). At 1500 or 2000 IU/kg VD3, adding 7000 IU/kg VA increased jejunal maltase activity, IL-10 (P < 0.05). At a 2000 IU/kg VD3, adding 9000 IU/kg VA increased IL-6, and TNF-α (P < 0.05). In summary, a dietary level of 7000 IU/kg of VA and 2000 IU/kg of VD3 can be a balanced combination to optimize feed intake and conversion, jejunal function, and tibia mineralization, consequently enhancing growth performance in goslings.

Effects of High-Dose Vitamin D3 Supplementation on Pig Performance, Vitamin D Content in Meat, and Muscle Transcriptome in Pigs

Vitamin D is known for its role in calcium homeostasis, bone health, and immune function. Recent research has explored its effects on muscle functionality and meat quality in pigs. This study examined high-dose vitamin D3 supplementation in pigs, focusing on growth, blood and tissue vitamin D3 levels, and muscle transcriptome changes. Thirty pigs were divided into three groups, given different amounts of oral supplementation: control, 5000 IU/kg and 10,000 IU/kg vitamin D3. Biochemical and haematological blood parameters, vitamin D content in blood and muscle, and kidney calcium content were evaluated. RNA-seq and qPCR analysed muscle transcriptome changes, while gene set enrichment analysis (GSEA) identified gene expression enrichments. Results showed that 5000 IU/kg vitamin D3 supplementation altered blood parameters like platelet anisocytosis and glucose levels but did not affect body weight, weight gain, or feed intake. Kidney calcium content increased with supplementation. The muscle (longissimus dorsi) vitamin D content increased, suggesting the potential for biofortified pork, although still not optimal as a dietary vitamin D source. Transcriptome analysis revealed minimal gene expression changes, with only the interferon-gamma receptor 2 (IFNGR2) gene differentially expressed at the highest dose. GSEA indicated enrichment in ATP metabolic processes and electron transport chain genes in the 5000 IU/kg group, and immune system, cholesterol, steroid, and fatty acid metabolism genes in the 10,000 IU/kg group. Despite literature suggesting a role for vitamin D in muscle gene expression and growth improvement, this study found its effects limited.

The protective role of prebiotics and probiotics on diarrhea and gut damage in the rotavirus-infected piglets

Rotavirus is one of the pathogenic causes that induce diarrhea in young animals, especially piglets, worldwide. However, nowadays, there is no specific drug available to treat the disease, and the related vaccines have no obvious efficiency in some countries. Via analyzing the pathogenesis of rotavirus, it inducing diarrhea is mainly due to disturb enteric nervous system, destroy gut mucosal integrity, induce intracellular electrolyte imbalance, and impair gut microbiota and immunity. Many studies have already proved that prebiotics and probiotics can mitigate the damage and diarrhea induced by rotavirus infection in hosts. Based on these, the current review summarizes and discusses the effects and mechanisms of prebiotics and probiotics on rotavirus-induced diarrhea in piglets. This information will highlight the basis for the swine production utilization of prebiotics and probiotics in the prevention or treatment of rotavirus infection in the future.

The Role of Vitamins in Mitigating the Effects of Various Stress Factors in Pigs Breeding

Good practices in farm animal care are crucial for upholding animal well-being, efficiency, and health. Pigs, like other farm animals, are exposed to various stressors, including environmental, nutritional, chemical, psychological, physiological, and metabolic stressors, which can disrupt their internal balance and compromise their well-being. Oxidative stress can adversely affect animal performance, fertility, and immunity, leading to economic losses for farmers. Dietary considerations are hugely important in attaining these objectives. This paper reviews studies investigating the impact of additional vitamin supplementation on stress reduction in pigs. Vitamin A can be beneficial in counteracting viral and parasitic threats. Vitamin B can be a potential solution for reproductive issues, but it might also be beneficial in reducing the effects of inappropriate nutrition. Vitamin C plays a vital role in reducing the effects of heat stress or exposure to toxins in pigs. Vitamin D proves to be beneficial in addressing stress induced mostly by infections and weaning, while vitamin E has been shown to mitigate the effects of toxins, heat stress, or transport stress. This review highlights the potential benefits of these dietary antioxidants in maintaining pig health, enhancing productivity, and counteracting the adverse effects of various stressors. Understanding the role of vitamins in pig nutrition and stress management is vital for optimising farm animal welfare and production efficiency.

The relationship of vitamin D deficiency and childhood diarrhea: a systematic review and meta-analysis

INTRODUCTION

Vitamin D deficiency may increase the risk of childhood diarrhea. We aim to carry out a review and meta-analysis of the evidence relating vitamin D insufficiency to childhood diarrhea.

METHODS

We searched PubMed, Ovid, Scopus, and Cochrane Library (from inception to August 2022), then independently reviewed the eligibility, and read full-text reviews for selected articles. Keywords used were 'vitamin D', '25-hydroxyvitamin D', 'vitamin D deficiency', 'diarrhea', 'gastroenteritis', 'children', and 'pediatric'. The search was limited to studies only in English and with available full-text. Year limitation was not applied in our search. Unpublished trials, dissertations, preliminary reports, conference abstracts, and repositories were excluded from the study. Newcastle-Ottawa Scale was used as the risk of bias assessment tool. Meta-analysis using the random-effects model was done.

RESULTS

Out of 5,565 articles, 12 articles were included in our systematic review, however only 7 articles were eligible for meta-analysis. Meta-analysis showed a statistically significant association between vitamin D deficiency and diarrhea in children in developing countries (OR = 1.79; 95% CI = 1.15 to 2.80; p = 0.01). On the secondary outcome, the association of vitamin D deficiency and duration or recurrences of diarrhea are conflicting.

CONCLUSIONS

There is an association between vitamin D deficiency and the prevalence of diarrhea. Future studies should evaluate the causal association, the impact of vitamin D deficiency on the severity of diarrhea, and whether vitamin D deficiency treatments affects the prevalence of diarrhea.

Impact of supplementation with dihydroxylated vitamin D3 on performance parameters and gut health in weaned Iberian piglets under indoor/outdoor conditions

BACKGROUND

Vitamin D may improve innate antimicrobial response and the integrity of the intestinal mucosal barrier representing an alternative to antibiotics for improving pig health. Therefore, benefits of dietary supplementation with a product based on vitamin D₃ metabolite-rich plant extracts were assessed in 252 purebred Iberian piglets for a period of 60 days. The study group received 1,25 dihydroxyvitamin D (1,25(OH)₂D) (100 ppm) in the conventional feed, which already included vitamin D (2000 IU in the starter and 1000 IU in the adaptation diets, respectively). Average daily gain (ADG), feed conversion ratio (FCR) and coefficient of variation of body weight (CV-BW) were assessed along the study. Blood samples, from 18 animals of the study group and 14 animals of the control group, were collected at selected time points to determine white blood cell count, concentration of vitamin D₃ and its metabolites, and IgA and IgG in serum. Histopathology, morphometry, and immunohistochemistry (IgA and FoxP3) from small intestine samples were performed on days 30 and 60 of the study from 3 animals per group and time point.

RESULTS

The ADG (493 vs 444 g/day) and FCR (2.3 vs 3.02) showed an improved performance in the supplemented animals. Moreover, the lower CV-BW indicated a greater homogeneity in the treated batches (13.17 vs 26.23%). Furthermore, a mild increase of IgA and in the number of regulatory T cells in the small intestine were observed in treated pigs.

CONCLUSIONS

These results highlight the benefits of this supplementation and encourage to develop further studies along other production stages.

Deoxyshikonin inhibited rotavirus replication by regulating autophagy and oxidative stress through SIRT1/FoxO1/Rab7 axis

BACKGROUND

Rotavirus (RV) is a double-stranded RNA virus. RV prevention and treatment remain a major public health problem due to the lack of clinically specific drugs. Deoxyshikonin is a natural compound isolated from the root of Lithospermum erythrorhizon and one of the shikonin derivatives which owns remarkable therapeutic effects on multiple diseases. The purpose of this research was to inquire Deoxyshikonin's role and mechanism in RV infection.

METHODS

Deoxyshikonin's function in RV was estimated using Cell Counting Kit-8 analysis, cytopathic effect inhibition assay, virus titer determination, quantitative real-time PCR, enzyme linked-immunosorbent assay, Western blot, immunofluorescence, and glutathione levels detection. Also, Deoxyshikonin's mechanism in RV was appraised with Western blot, virus titer determination, and glutathione levels detection. Moreover, Deoxyshikonin's function in RV in vivo was determined using animal models, and diarrhea score analysis.

RESULTS

Deoxyshikonin owned anti-RV activity and repressed RV replication in Caco-2 cells. Furthermore, Deoxyshikonin reduced autophagy and oxidative stress caused by RV. Mechanistically, Deoxyshikonin induced low protein levels of SIRT1, ac-Foxo1, Rab7, VP6, low levels of RV titers, low autophagy and oxidative stress. SIRT1 overexpression abolished the effects of Deoxyshikonin on RV-treated Caco-2 cells. Meanwhile, in vivo research affirmed that Deoxyshikonin also possessed anti-RV function, and this was reflected in increased survival rate, body weight, GSH levels, and decreased diarrhea score, RV virus antigen, LC-3II/LC3-I.

CONCLUSION

Deoxyshikonin reduced RV replication through mediating autophagy and oxidative stress via SIRT1/FoxO1/Rab7 pathway.

Sodium butyrate protects against rotavirus-induced intestinal epithelial barrier damage by activating AMPK-Nrf2 signaling pathway in IPEC-J2 cells

Rotavirus (RV) mainly infects intestinal epithelial cells, which leads to diarrhea in newborn piglets with dysfunction in the intestinal mucosal mechanical barrier. Sodium butyrate (SB) is one of the metabolites excreted by gut microbes. However, the protective effect of SB on RV infection induced intestinal mucosal mechanical barrier injury and its potential mechanism has not been well elucidated. In the present study, IPEC-J2 cells with RV infection was a model of intestinal mucosal mechanical barrier injury. Our results demonstrated that the appropriate concentration of SB can effectively alleviate TJ structural damage and up-regulating the expression of TJ-related genes. Furthermore, the appropriate concentration of SB can effectively reverse the increase of intracellular reactive oxygen species (ROS) and malondialdehyde (MDA) level induced by RV infection. Meanwhile, the levels of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-px) and antioxidant proteins NAD(P)H dehydrogenase quinone 1 (NQO1) and heme oxygenase-1 (HO-1) were increased through SB treatment. In addition, we found that SB increased cellular antioxidant capacity by activating the adenosine monophosphate-activated protein kinase (AMPK)-nuclear factor erythroid 2-related factor (Nrf2) signaling pathway and the cytoprotective effect of SB is limited by GPR109A siRNA. Thus, our findings revealed that SB reduces oxidative stress caused by RV infection and restores the intestinal mucosal mechanical barrier function by activating the AMPK-Nrf2 signal pathway mediated by the receptor GPR109A.

Serum 25-hydroxyvitamin D and fatty acids in relation to the risk of microbial infections in children: The TRIGR Divia study

BACKGROUND & AIMS

Nutrient status may affect the risk of microbial infections and play a role in modulating the immune response against such infections. The aim of this study was to determine whether serum 25-hydroxyvitamin D [25(OH)D] and serum fatty acids in infancy are associated with microbial infections by the age of 18 months.

METHODS

Altogether 576 newborn infants from Trial to Reduce IDDM in the Genetically at Risk (TRIGR) born between 2002 and 2007 were included. The concentration of 25(OH)D vitamin and proportions of 26 fatty acids (presented as % of total fatty acids) were analyzed in cord blood serum and in sera taken at 6, 12, and 18 months of age. The cord blood samples and mean of 6-18-month values were used as exposures. Infections were detected by screening IgG antibodies against 10 microbes using enzyme immunoassay and antibodies against 6 coxsackievirus B serotypes by plaque neutralization assay in serum samples taken at 18 months of age.

RESULTS

A higher proportion of n-3 polyunsaturated fatty acids (PUFAs) and especially long-chain n-3 PUFAs at birth and at the age of 6-18 months was associated with decreased risk of coxsackievirus B2 infection unadjusted and adjusted for region, case-control status, and maternal type 1 diabetes. Higher proportion of docosapentaenoic acid (DPA, 22:5 n-3) at birth was associated with a decreased risk of respiratory syncytial virus infection. 25(OH)D vitamin concentration was not consistently associated with the risk of infections. When only infected children were included docosahexaenoic acid (DHA, 22:6 n-3) and arachidonic acid (20:4 n-6) proportions were positively associated with IgG antibody levels against influenza A virus. 25(OH)D vitamin concentration showed an inverse association with rotavirus IgG levels among children with rotavirus seropositivity.

CONCLUSIONS

In young children with increased susceptibility to type 1 diabetes, long-chain n-3 PUFAs may influence the risk of viral infections and immune response against the infections. However, this association may depend on the type of virus suggesting virus-specific effects.

Interactive effect of dietary levels of calcium and 25-hydroxy vitamin D3 on the performance, serum biochemical concentration and digestibility of laying hens from 61 to 70 weeks of age

Objective

The present research was conducted to evaluate the interactive effect of dietary concentration of calcium (Ca) and 25-hydroxy vitamin D3 (25OHD3) on the performance, blood composition and digestibility of laying hens.

Methods

A total of 540 Hy-line brown laying hens aged 61 to 70 weeks were randomly allotted in a 3×3 factorial arrangement, consisting of three levels of 25OHD3 (0, 25, and 50 μg/kg) and three levels of Ca (3.5%, 4.0%, and 4.5%). All diets had basal concentration of 3,000 IU/kg of vitamin D3 including the 2,800 kcal/kg of metabolic energy and 16% of crude protein.

Results

The results showed that interactive effect (p<0.05) between Ca and 25OHD3 was such that dietary 25OHD3 linearly increased interleukin-6 at all levels of Ca inclusion. Interaction (p<0.05) occurred with the highest parathyroid hormone in laying hens that received dietary concentration of Ca (3.5%) with 25OHD3 (50 μg/kg), and Ca (4.0%) with 25OHD3 (50 μg/kg). Egg production and egg weight significantly (p<0.05) increased in the 4.5% Ca group compared to the 3.5% to 4.0% Ca groups. Egg shell thickness and tibia bone length also increased (p<0.05) in groups fed a high-Ca diet (4.0% to 4.5%). Phosphorus digestibility significantly (p<0.05) increased along with dietary Ca level. Among the tested 25OHD3 groups, higher (p<0.05) egg production and tibia thickness were present in hens fed 50 μg/kg of 25OHD3. Furthermore, Ca digestibility serum Ca and 25OHD3 were significantly increased in group offered 50 μg/kg of 25OHD3.

Conclusion

The results gathered in this study indicate that dietary concentrations of 4.0% to 4.5% Ca and 50 μg/kg 25OHD3 improve the performance of hens from 61 to 70 weeks of age.

Vitamin D Levels in Sows from Five Danish Outdoor Herds

Simple Summary

A cross-sectional study on vitamin D₃ status was conducted in five Danish outdoor sow herds throughout August 2020. The aim was to determine the vitamin D status of outdoor sows during the peak sunshine season. The average 25-hydroxyvitamin D₃ concentration in serum was 67 ± 16 ng 25(OH)D₃/mL in outdoor sows, which is considerably higher than levels found in sows housed indoors and fed a standard diet supplemented with vitamin D.

Abstract

Vitamin D is essential for sow health and productivity. Standard sow feed is therefore supplemented with vitamin D₃ or 25-hydroxyvitamin D₃ (25(OH)D₃). However, it is uncertain whether the levels achieved are adequate for optimal performance. Currently, information on serum levels of vitamin D in pigs reared under both indoor and outdoor conditions is lacking. In August 2020, we obtained blood samples from 97 organic newly weaned sows housed outdoors during pregnancy and farrowing and used these to test for vitamin D in serum. The average concentration was 67 ± 16 ng 25(OH)D₃/mL with a range of 32 to 134 ng 25(OH)D₃/mL. The vitamin D₃ content was 21 ± 7 ng/mL, ranging from 9 to 48 ng/mL. The average number of hours of sun from June to August was 7.0 ± 0.5 h/day. Parity, farm and body condition score did not significantly affect serum levels of 25(OH)D₃.

Effects of Dietary Zinc Sources on Growth Performance and Gut Health of Weaned Piglets

The present study aimed to investigate the effects of dietary zinc sources on the growth performance and gut health of weaned piglets. In total, 96 Duroc × Landrace × Yorkshire (DLY) weaned piglets with an initial average body weight of 8.81±0.42kg were divided into four groups, with six replicates per treatment and four pigs per replicate. The dietary treatment groups were as follows: (1) control group, basal diet; (2) zinc sulphate (ZnSO4) group, basal diet +100mg/kg ZnSO4; (3) glycine zinc (Gly-Zn) group, basal diet +100mg/kg Gly-Zn and (4) zinc lactate group, and basal diet +100mg/kg zinc lactate. The whole trial lasted for 28days. Decreased F/G was noted in the Gly-Zn and zinc lactate groups (p<0.05). The zinc lactate group had a lower diarrhea rate than the control group (p<0.05). Moreover, the ZnSO4, Gly-Zn, and zinc lactate groups had significantly higher apparent total tract digestibility of dry matter (DM), crude protein (CP), ether extract (EE), crude ash, and zinc than the control group (p<0.05). The Gly-Zn and zinc lactate groups had higher jejunal villus height and a higher villus height:crypt depth ratio than the control group (p<0.05). In addition, the ZnSO4, Gly-Zn and zinc lactate groups had a significantly lower mRNA expression level of jejunal ZRT/IRT-like protein 4 (ZIP4) and higher mRNA expression level of jejunal interleukin-1β (IL-1β) than the control group (p<0.05). The mRNA expression level of jejunal zinc transporter 2 (ZNT2) was higher and that of jejunal Bcl-2-associated X protein (Bax) was lower in the Gly-Zn and zinc lactate groups than in the control group (p<0.05). Moreover, the zinc lactate group had a higher count of Lactobacillus spp. in the cecal digesta and higher mRNA expression levels of jejunal occludin and mucin 2 (MUC2) than the control group (p<0.05). In conclusion, dietary supplementation with 100mg/kg ZnSO4, Gly-Zn, or zinc lactate could improve the growth performance and gut barrier function of weaned piglets. Dietary supplementation with organic zinc, particularly zinc lactate, had the best effect.

25-hydroxycholecalciferol reverses heat induced alterations in bone quality in finisher broilers associated with effects on intestinal integrity and inflammation

BACKGROUND

Alterations in ambient temperature have been associated with multiple detrimental effects on broilers such as intestinal barrier disruption and dysbiosis resulting in systemic inflammation. Inflammation and 25-hydroxycholecalciferol (25-OH-D₃) have shown to play a negative and positive role, respectively, in the regulation of bone mass. Hence the potential of 25-OH-D₃ in alleviating heat induced bone alterations and its mechanisms was studied.

RESULTS

Heat stress (HS) directly induced a decrease in tibia material properties and bone mass, as demonstrated by lower mineral content, and HS caused a notable increase in intestinal permeability. Treatment with dietary 25-OH-D₃ reversed the HS-induced bone loss and barrier leak. Broilers suffering from HS exhibited dysbiosis and increased expression of inflammatory cytokines in the ileum and bone marrow, as well as increased osteoclast number and activity. The changes were prevented by dietary 25-OH-D₃ administration. Specifically, dietary 25-OH-D₃ addition decreased abundance of B- and T-cells in blood, and the expression of inflammatory cytokines, especially TNF-α, in both the ileum and bone marrow, but did not alter the diversity and population or composition of major bacterial phyla. With regard to bone remodeling, dietary 25-OH-D₃ supplementation was linked to a decrease in serum C-terminal cross-linked telopeptide of type I collagen reflecting bone resorption and a concomitant decrement in osteoclast-specific marker genes expression (e.g. cathepsin K), whereas it did not apparently change serum bone formation markers during HS.

CONCLUSIONS

These data underscore the damage of HS to intestinal integrity and bone health, as well as that dietary 25-OH-D₃ supplementation was identified as a potential therapy for preventing these adverse effects.

Vitamin D and immuno-pathology of COVID-19: many interactions but uncertain therapeutic benefits

Introduction: COVID-19 pandemic has caused huge loss of human lives and extensive socio-economic damages. The immuno-pathology of this disease is neither clearly understood nor there are effective drugs for severe cases of COVID-19. Repurposing of available drugs for the treatment of COVID-19 is imperative.Areas Covered: This review has gathered the evidence from PubMed, Google Scholar, WHO, and other reliable websites on COVID-19 and summarized the existing knowledge of the immuno-pathology of COVID-19. We elucidated how vitamin D through its diverse actions on immune effector cells, epithelial cells, or renin-angiotensin-aldosterone system could have a modulatory role on the pathogenic mechanisms of COVID-19. The epidemiological evidence associating vitamin D deficiency with the severity and incidence of COVID-19 is also presented. However, the evidence of clinical benefit to patients of COVID-19 from randomized controlled trials with vitamin D has not come as yet.Expert opinion: It is now established that fatality of COVID-19 is primarily determined by hyperactivation of the host's innate immune system in response to SARS-CoV-2 invasion, and thus the research on the immuno-modulatory and other roles of vitamin D against viral infections should be pursued vigorously. This would be also useful for future pandemics caused by other novel viruses.

Rotavirus vaccines performance: dynamic interdependence of host, pathogen and environment

INTRODUCTION

As of January 2021, rotavirus vaccination programs have been implemented in 109 countries and their use has resulted in a positive impact on rotavirus-related diarrheal hospitalizations and mortality in children below 5 years of age. Despite these successes, several countries in Africa and Asia where disease burden is high have not yet implemented rotavirus vaccination at all or at a scale sufficient enough to demonstrate impact. This could be, among other reasons, due to poor vaccine coverage and the modest levels of efficacy and effectiveness of the vaccines in these resource-limited settings.

AREAS COVERED

We review various factors related to the human host (malnutrition, maternally derived antibodies and breastfeeding, genetic factors, blood group, and co-administration with oral polio vaccine), rotavirus pathogen (force of infection, strain diversity and coinfections), and the environment (related to the human microbiome) which reflect complex and interconnected processes leading to diminished vaccine performance in resource-limited settings.

EXPERT OPINION

Addressing the limiting factors for vaccine efficacy is needed but likely to take a long time to be resolved. An immediate solution is to increase the immunization coverage to higher values generating an overall effect of adequate proportion of protected population to reduce the prevalence of rotavirus disease.

Recent advances of vitamin D in immune, reproduction, performance for pig: a review

Vitamin D (VD) has been reported to play multiple and significant roles in improving pig health via modulating calcium and phosphorus homeostasis, skeletal muscle development and the immune system. Apart from food, photochemical action of 7-dehydrocholesterol in the skin is the main source of this molecule for pigs. The VD from dietary intake or photosynthesized via skin can be absorbed into the liver for hydroxylation, and further hydroxylated into the hormone form of VD (1,25-dihydroxyvitamin D3 or 1,25(OH)2D3) in the kidney. As a sterol hormone, 1,25(OH)2D3 is able to bind with the VD receptor (VDR), and this ligand-receptor complex (VDR/retinoic X receptor) translocates from the cytoplasm into the nucleus to regulate gene expression, thus modulating metabolism. In this review, we summarized the recent studies regarding the non-skeletal health benefits of VD for pigs, and focused on the recent advances in the cellular and molecular mechanisms of VD that affects the immune system and reproductive health. This review provides a reference for future research and application of VD in pigs.

Dietary 25-hydroxycholecalciferol supplementation improves performance, immunity, antioxidant status, intestinal morphology, and bone quality in weaned piglets

BACKGROUND

25-Hydroxycholecalciferol (25OHD₃ ) is a new feed additive, which is a potential alternative to vitamin D₃ in swine nutrition. The objective of this study was to determine the effects of different doses of 25OHD₃ supplementation on performance, immunity, antioxidant capacity, intestinal morphology and bone quality in piglets.

RESULTS

As dietary 25OHD₃ supplementation increased, the average daily gain (ADG) improved (P < 0.05) quadratically during days 1-14, and tended to increase (P = 0.06) quadratically during the overall period of the experiment. Increasing 25OHD₃ supplementation increased (linear effect, P < 0.05) the serum 25OHD₃ level and serum glutathione peroxidase (GSH-Px) activity. On day 14, serum immunoglobulin A (IgA) was increased (linear and quadratic effects, P < 0.05) as dietary 25OHD₃ supplementation increased. On day 28, serum IgA level was higher (P < 0.05) linearly and the complement 3 (C3) level was reduced (P < 0.05) linearly as dietary supplementation of 25OHD₃ increased. The mucosal GSH-Px activity of the small intestine was higher (quadratic effect, P < 0.05) with increasing 25OHD₃ supplementation. Jejunal villus height (P = 0.06) and villus height to crypt depth ratio (P = 0.07) tended to increase quadratically, and the villus height to crypt-depth ratio of the ileum increased (P < 0.05) linearly and quadratically with increasing 25OHD₃ supplementation. Dietary supplementation with an increasing level of 25OHD₃ increased breaking strength of tibias and femurs (quadratic effect, P < 0.05).

CONCLUSION

Increasing dietary 25OHD₃ supplementation partly improved performance, immunity, antioxidant status, intestinal morphology, and bone properties of weaned piglets. © 2020 Society of Chemical Industry.

Effects of Early Transplantation of the Faecal Microbiota from Tibetan Pigs on the Gut Development of DSS-Challenged Piglets

The present study was conducted to investigate the effects of early transplantation of the faecal microbiota from Tibetan pigs on the gut development of dextran sulphate sodium- (DSS-) challenged piglets. In total, 24 3-day-old DLY piglets were divided into four groups (n = 6 per group); a 2 × 2 factorial arrangement was used, which included faecal microbiota transplantation (FMT) (from Tibetan pigs) and DSS challenge. The whole trial lasted for 55 days. DSS infusion increased the intestinal density, serum diamine oxidase (DAO) activity, and colonic Escherichia coli count (P < 0.05), and decreased the Lactobacillus spp. count and mRNA abundances of epidermal growth factor (EGF), glucagon-like peptide-2 (GLP-2), insulin-like growth factor 1 (IGF-1), occludin, mucin 2 (MUC2), regeneration protein IIIγ (RegIIIγ), and interleukin-10 (IL-10) in the colon (P < 0.05). FMT increased the Lactobacillus spp. count and mRNA abundances of GLP-2, RegIIIγ, and IL-10 in the colon (P < 0.05), and decreased the intestinal density, serum DAO activity, and colonic E. coli number (P < 0.05). In addition, in DSS-challenged piglets, FMT decreased the disease activity index (P < 0.05) and attenuated the effect of DSS challenge on the intestinal density, serum DAO activity, and colonic E. coli number (P < 0.05). These data indicated that the faecal microbiota from Tibetan pigs could attenuate the negative effect of DSS challenge on the gut development of piglets.

Evaluating association of vaccine response to low serum zinc and vitamin D levels in children of a birth cohort study in Dhaka

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MAL-ED Bangladesh birth cohort data used in the analysis.

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Relationship between vaccine titers and micronutrient data explored.

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Positive association found between serum zinc level and tetanus vaccine titer.

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The finding implicates the importance of improving zinc nutrition status of the children.

Background

Vaccine-preventable infectious diseases are often responsible for childhood morbidity and high rates of mortality. Immune response to the vaccine is associated with multiple factors in early childhood and measured by antibody titers. Among them, micronutrient deficiencies such as vitamin D and zinc deficiencies are the most important in resource-limited settings like Bangladesh.

Objective

We aimed to evaluate the association of vaccine response to low serum zinc and vitamin D levels in children.

Methods

We evaluated vaccine response for measles and poliovirus, tetanus and pertussis toxoid, and Ig A antibody levels to rotavirus by ELISA and serum vitamin D and zinc at 7 and 15 months in the MAL-ED birth cohort of the Bangladesh site. By using population-specific generalized estimating equations (GEE), the association between each explanatory variable and the binary outcome variable was examined longitudinally where the dependent variable was vaccine titers and the independent variables were low serum vitamin D and zinc levels.

Results

The GEE multivariable model identified a positive association between serum zinc level and tetanus vaccine titer (OR: 1.84; 95% CI: 1.07–3.17 and p value = 0.028) after adjusting for age, gender, birth weight, WAMI score, diarrhea, ALRI, exclusive breastfeeding, serum ferritin, serum retinol and undernutrition (stunting, wasting, underweight). No association was found between the rest of the vaccine titers with serum vitamin D and zinc level (p > 0.05).

Conclusion

In the MAL-ED birth cohort, where children were followed for five years, serum zinc level had a positive impact on tetanus vaccine titers.

Effects of maternal 25-hydroxycholecalciferol during the last week of gestation and lactation on serum parameters, intestinal morphology and microbiota in suckling piglets

This study was conducted to test the effects of maternal 25-hydroxycholecalciferol (25OHD₃) supplementation on serum parameters, intestinal morphology and microbiota in suckling piglets. The experiment started on day 107 of gestation and lasted until piglets were weaned on day 21 of lactation. Thirty-two sows were allocated randomly to two treatments (ND diet, basal diet with 2000 IU/kg of vitamin D₃; 25-D diet, basal diet with 50 μg/kg 25OHD₃). Results showed that maternal 25-D treatment increased (p < 0.05) serum 25OHD₃ concentration in the umbilical cords, which led to higher (p < 0.05) serum 25OHD₃ concentration of suckling piglets from 25-D sows. The GSH-Px activity in colostrum was higher (p < 0.05), as well as SOD and GSH-Px activities in milk, were higher (p < 0.05) in 25-D sows than ND sows. Compared with piglets suckling ND sows, piglets suckling 25-D sows had higher (p < 0.05) serum SOD activity on day 7, 14 and 21 of lactation. On day 21 of lactation, piglets form 25-D sows had greater (p < 0.05) serum levels of GH and IGF-I and lower (p < 0.05) serum DAO activity than those from ND sows. Piglets from 25-D sows had higher (p < 0.05) jejunal villus height than those from ND sows. Feeding 25OHD₃ to sows tended to increase (p < 0.10) the species richness in the colonic digesta of suckling piglets, as reflected by the α-diversity index of Chao-1. In the caecal digesta, the α-diversity for bacterial community analysis of Simpson and Shannon was lower (p < 0.05) in 25-D piglets than ND piglets. The relative abundances of colonic Alloprevotella and caecal Lactobacillus were significantly higher, while the population of caecal [Eubacterium]_coprostanoligenes_group was lower (p < 0.05) in 25-D piglets than ND piglets. In conclusion, maternal 25OHD₃ supplementation partly improved antioxidant status in sows and suckling piglets and altered gut microbiota in the hindgut of piglets.

Beet Pulp: An Alternative to Improve the Gut Health of Growing Pigs

The present study aimed to investigate the effects of dietary fiber on the gut health of growing pigs. In total, 30 growing pigs with an initial average body weight of 45.8 ± 2.78 kg were divided into three groups with 10 replicates per treatment, and one pig per replicate. The treatments included a corn-soybean meal-based diet (control group, 1.5% crude fiber (CF)), corn-soybean meal + beet pulp-based diet (beet pulp group, 5.74% CF) and corn-soybean meal-based diet (feed intake-pairing group (pairing group); the feed intake was equal to the beet pulp group, 1.5% CF). The whole trial lasted 28 days. The beet pulp group had a longer length of the large intestine, higher weight of the small intestine and whole intestine, greater density of the large intestine and whole intestine, and higher villus height in the jejunum and ileum than the control group (p < 0.05). The messenger RNA (mRNA) expression levels of epidermal growth factor (EGF), glucagon-like peptide 2 (GLP-2), and glucagon-like peptide 2 receptor (GLP-2R) in the duodenum, EGF and GLP-2 in the jejunum, EGF in the ileum, and GLP-2 in the colon were higher in the beet pulp group than in the control group (p < 0.05). Moreover, the apparent total tract digestibility of crude ash, energy, dry matter (DM), and crude protein (CP) was lower in the beet pulp group than in the control group (p < 0.05), while the apparent total tract digestibility of CF, the activity of jejunal lactase, and the mRNA abundance of duodenal GLP-2 were higher in the beet pulp group than in the control and pairing groups (p < 0.05). In addition, the beet pulp group had more goblet cells in the colon, more Bifidobacterium spp. in the cecal digesta, higher concentrations of acetic acid and butyric acid in the cecal digesta, and higher mRNA abundance of duodenal regeneration protein Ⅲγ (REG-Ⅲγ), jejunal mucin 2 (MUC-2), and ileal G protein-coupled receptor 43 (GPR-43) than the control group (p < 0.05). However, these parameters did not differ between the control and pairing groups (p > 0.05). These findings indicate feeding a high-fiber diet (5.74% CF, obtained from beet pulp) to pigs could modulate the gut microbiota composition, increase the short-chain fatty-acid (SCFA) content in the hindgut, and improve gut health, which is independent of the feed intake.

Effect of UVB light on vitamin D status in piglets and sows

Piglets are born with very low levels of vitamin D. Feed is the only source of vitamin D for pigs kept indoors, and the levels in feed are restricted by European legislation. We aimed to study the effect of lamps releasing ultraviolet type B (UVB) light on the vitamin D status (serum 25-hydroxyvitamin D) in sows and piglets in a Danish indoor herd. A randomized trial with a parallel group design was initiated with two groups receiving a daily UVB-dose of maximum 0.7 standard erythema dose (SED) or 1 SED, in addition to a control group. The three groups included in the study consisted of 15 sows and their 195 offspring. Blood samples were taken from the piglets and sows on day 1, 12, and 24. Results showed no difference between the groups in serum levels of 25(OH)D₃ or vitamin D₃ on day 1, with the mean (±SD) for piglets being 0.96 ± 0.26 ng/mL and 0.06 ± 0.04 ng/mL, respectively. For sows, the values were 16 ± 3 ng/mL 25(OH)D₃ and 3 ± 0.8 ng/mL vitamin D₃ on day 1. A significant difference (p < 0.001) in serum 25(OH)D₃ between the groups receiving UVB light and the control group was observed on both day 12 and day 24. On day 24, the piglet control group had 5.5 ± 2 ng/mL 25(OH)D₃ and 0.4 ± 0.2 ng/mL vitamin D₃. For the UVB groups, the values were 21.6 ± 10. ng/mL 25(OH)D₃ and 8.3 ± 2.5 ng/mL vitamin D₃ for the 0.7 SED group and 19.5 ± 6.0 ng/mL 25(OH)D₃ and 7.6 ± 3.4 ng/mL vitamin D₃ for the 1 SED group. For the sows, the values were 25.6 ± 5.5 ng/mL 25(OH)D₃ and 6.6 ± 1.2 ng/mL vitamin D₃ for the control group, 66.7 ± 13.5 ng/mL 25(OH)D₃ and 21.3 ± 2.9 ng/mL vitamin D₃ for 0.7 SED group and 67 ± 15 ng/mL 25(OH)D₃ and 25 ± 5 ng/mL vitamin D₃ for the 1 SED. No significant difference was found between the two UVB groups for either piglets or sows. The use of lamps releasing UVB light is therefore suggested to be an efficient way to improve the vitamin D status of both sows and piglets.

High dose of dietary vitamin D3 modulated the yellow catfish (Pelteobagrus fulvidraco) splenic innate immune response after Edwardsiella ictaluri infection

Vitamin D₃ (VD₃) has been shown to modulate the innate immune response in mammals but this has been rarely reported in fish. The current study found that increasing dietary VD₃ content can reduce the density of yellow to dark brown pigmented macrophage aggregates (PMAs) in the spleens of yellow catfish infected with Edwardsiella ictaluri. The results of next-generation sequencing showed that a high dose of dietary VD₃ (16,600 IU/kg) mainly affected the splenic immune response during Edwardsiella ictaluri infection via negative regulation of 'NF-κΒ transcription factor activity', 'NIK/NF-κΒ signaling' and the 'i-kappab kinase/NF-κΒ signaling' pathways. Follow-up qPCR showed that dietary VD₃ increased the expression of NF-κΒ inhibitor iκb-α, decreased the expression of nf-κb p65, il-6, il1-β and tnf-α, and down-regulated the expression of nik, ikks and nf-κb p52 in the NIK/NF-kappaB signaling pathway. The above results indicate that dietary VD₃ can modulate the splenic innate immune response of yellow catfish after Edwardsiella ictaluri infection by inhibiting the NF-κB activation signaling pathways.

Capsulized faecal microbiota transplantation ameliorates post-weaning diarrhoea by modulating the gut microbiota in piglets

Early weaning-induced stress causes diarrhoea, thereby reducing the growth performance of piglets. Gut bacterial dysbiosis has emerged as a leading cause of post-weaning diarrhoea. The present study aimed to investigate the effect of capsulized faecal microbiota transplantation (FMT) on the gut bacterial community, immune response and gut barrier function of piglets. Thirty-two weaned barrows were randomly divided into two groups. The recipient group was inoculated orally with capsulized faecal microbiota of healthy Tibetan pigs during the whole period of the trial, while the control group was given an empty capsule. The feed-to-gain ratio, diarrhoea ratio, and histological damage score of recipient piglets were significantly decreased. FMT treatment significantly increased the colon length of piglets. Furthermore, the relative abundances of Firmicutes, Euryarchaeota, Tenericutes, Lactobacillus, and Methanobrevibacter in the colon of recipient piglets were increased, and the relative abundances of Campylobacter and Proteobacteria were significantly decreased compared with those in the control group. CD4⁺ lymphocytes and CD4⁺/CD8⁺ ratio in the peripheral blood of recipient piglets were significantly increased. FMT treatment increased the IL-4 and IL-10 levels and decreased the TNF-α and INF-γ levels in the colonic tissue of piglets. The recipient piglets’ mRNA expression of TLR2, TLR8, NF-κB, and iNOS was significantly regulated. In addition, FMT significantly enhanced the gene expression of ZO-1. Overall, treatment with capsulized FMT ameliorated diarrhoea in piglets, with significant effects on limiting colon inflammatory responses, downregulating the TLR signalling pathway and the gene expression of iNOS, and strengthening intestinal barrier function by modulating the constituents of the gut microbiota.

Vitamin D Induces Differential Effects on Inflammatory Responses During Bacterial and/or Viral Stimulation of Human Peripheral Blood Mononuclear Cells

Streptococcus pneumoniae (pneumococcus) and respiratory syncytial virus (RSV) are the leading causes of respiratory infections amongst children <5 years of age. Co-infection with these pathogens is common during early life and often associated with increased disease severity. Epidemiological studies have shown that low levels of Vitamin D₃ (VitD₃) are associated with increased susceptibility to respiratory pathogens. However, the role of VitD₃ in the context of pneumococcal and RSV exposure are poorly understood. We found that VitD₃ significantly reduced Th17 cell expression and IL-17A and IL-22 secretion in peripheral blood mononuclear cells (PBMCs) when stimulated with a pneumococcal whole cell antigen (WCA). Levels of IFN-γ were also decreased whilst IL-10 and IL-1β were increased. Effects of VitD₃ on innate responses following RSV stimulation was limited, only reducing IL-6. VitD₃ also reduced the number of TLR2+CD14+ monocytes, whilst increasing TLR7+CD14+ monocytes and TLR4+CD56+ NK cells. In WCA-stimulated PBMCs, VitD₃ increased IL-1β levels but reduced TLR2+CD14+ monocytes. For pneumococcal WCA-RSV co-stimulation, VitD₃ only had a limited effect, mainly through increased IL-1β and RANTES as well as TLR4+CD56+ NK cells. Our results suggest that VitD₃ can modulate the inflammatory response to pneumococci but has limited effects during viral or bacterial-viral exposure. This is the first study to examine the effects of VitD₃ in the context of pneumococcal-RSV co-stimulation, with important implications on the potential role of VitD₃ in the control of excessive inflammatory responses during pneumococcal and RSV infections.

Manipulation of Intestinal Antiviral Innate Immunity and Immune Evasion Strategies of Porcine Epidemic Diarrhea Virus

Porcine epidemic diarrhea virus (PEDV) infection causes watery diarrhea, dehydration, and high mortality in neonatal pigs, due to its clinical pathogenesis of the intestinal mucosal barrier dysfunction. The host's innate immune system is the first line of defence upon virus invasion of the small intestinal epithelial cells. In turn, the virus has evolved to modulate the host's innate immunity during infection, resulting in pathogen virulence, survival, and the establishment of successful infection. In this review, we gather current knowledge concerning the interplay between PEDV and components of host innate immunity, focusing on the role of cytokines and interferons in intestinal antiviral innate immunity, and the mechanisms underlying the immune evasion strategies of PEDV invasion. Finally, we provide some perspectives on the potential prevention and treatment for PEDV infection.

Effects of Bacillus subtilis DSM32315 supplementation and dietary crude protein level on performance, gut barrier function and microbiota profile in weaned piglets1

Seventy-two piglets aged at 25 d were chosen to investigate the effects of Bacillus subtilis DSM32315 supplementation in diets with different protein levels on growth performance, intestinal barrier function, and gut microbiota profile in a 42-d trial. The animals were allotted to four treatment groups in a randomized complete block design involving a 2 (protein levels) × 2 (probiotic levels) factorial arrangement of treatments. Two protein levels included the high CP (HP) diets (0 to 14 d, 20.5%; 15 to 42 d, 19.5%) and the low CP (LP) diets (0 to 14 d, 18%; 15 to 42 d, 17%), and added probiotic (PRO) levels included at 0 and 500 mg/kg diet. Two interactions between CP and PRO for ADG (P < 0.01) and F/G (P < 0.05) were observed in phase 1. Within the piglets given the LP diet, probiotic supplementation increased ADG and decreased F/G ratio. Likewise, there were interactions between CP and PRO on the digestibility of CP (P < 0.01) and EE (P < 0.05), and probiotic supplementation increased the digestibility of CP and ether extract (EE) of piglets fed with LP diet, but that was not the case for piglets fed with HP diet. Furthermore, there were interactions between CP and PRO on villus height (P < 0.01) and villus height:crypt depth ratio (P < 0.05) in ileum. Piglets fed with LP diet containing probiotic had the greatest villus height and villus height:crypt depth ratio in ileum among treatments. There were also main effects of PRO on the propionic acid (P < 0.05) and butyric acid (P < 0.05), and the concentrations of propionic acid and butyric acid in colonic digesta were increased with the inclusion of probiotic in diet. Piglets fed with LP diet containing probiotic had the greatest population of Bacillus and Bifidobacterium (P < 0.05) in colon. In addition, there were interactions between CP and PRO on the mRNA expressions of occludin-1 (P < 0.05), epidermal growth factor (EGF) (P < 0.05), and insulin-like growth factor 1 receptor (IGF-1R) (P < 0.05). The LP fed piglets plus probiotic exhibited the greatest mRNA expressions of occludin-1, EGF, and IGF-1R in ileum compared with other treatments. In conclusion, moderate dietary protein restriction combining with the addition of B. subtilis DSM32315 synergistically increased growth performance, altered hindgut bacterial composition and metabolites, maintained intestinal barrier function in ileum of piglets.

Dietary 25-Hydroxyvitamin D3 Supplementation Alleviates Porcine Epidemic Diarrhea Virus Infection by Improving Intestinal Structure and Immune Response in Weaned Pigs

Simple Summary

Porcine epidemic diarrhea is one of the major problems in current swine husbandry worldwide, and effective measures for prevention and treatment are scarce. We found that high dose 25-hydroxyvitamin D₃ supplementation could ease intestinal injury and inhibit intestinal immune response induced by porcine epidemic diarrhea virus (PEDV), suggesting that feeding a high dose of 25-hydroxyvitamin D₃ could be used as an approach against PEDV infection.

Abstract

We conducted this experiment to determine if feeding 25-hydroxyvitamin D₃ (25(OH)D₃) to weaned pigs would alleviate porcine epidemic diarrhea virus (PEDV) infection and immune response. Forty-two weaned pigs were allotted to 1 of 6 dietary 25(OH)D₃ treatments (5.5, 5.5, 43.0, 80.5, 118.0, 155.5 μg 25(OH)D₃/kg diet) for 26 days. On day 22 of the trial, all the treatments were orally administrated with PEDV except for one of the 5.5 μg 25(OH)D₃/kg treatments, which was challenged with the same volume of sterile saline and served as control. Another 5.5 μg 25(OH)D₃/kg group for PEDV challenge was named CON-PEDV. Average daily gain (p < 0.05) was reduced by PEDV infection. PEDV administration also induced severe diarrhea (p < 0.05), reduction of villous height and the ratio of villous height to crypt depth, and increase of crypt depth and serum diamine oxidase activity (p < 0.05). Serum IgM and complement component 4 levels were increased by PEDV challenge. However, 155.5 μg 25(OH)D₃/kg supplementation alleviated intestinal damage (p < 0.05) compared with CON-PEDV. Furthermore, 155.5 μg 25(OH)D₃/kg supplementation downregulated the mRNA abundance of inflammatory cytokines and interferon signal pathway-related genes (p < 0.05) compared with CON-PEDV. These results suggested that dietary supplementation of 155.5 μg 25(OH)D₃/kg could alleviate intestinal damage and protect against PEDV-induced inflammatory status.

Vitamin D Alleviates Rotavirus Infection through a Microrna-155-5p Mediated Regulation of the TBK1/IRF3 Signaling Pathway In Vivo and In Vitro

(1) Background: Vitamin D (VD) plays a vital role in anti-viral innate immunity. However, the role of VD in anti-rotavirus and its mechanism is still unclear. The present study was performed to investigate whether VD alleviates rotavirus (RV) infection through a microRNA-155-5p (miR-155-5p)-mediated regulation of TANK-binding kinase 1 (TBK1)/interferon regulatory factors 3 (IRF3) signaling pathway in vivo and in vitro. (2) Methods: The efficacy of VD treatment was evaluated in DLY pig and IPEC-J2. Dual-luciferase reporter activity assay was performed to verify the role of miR-155-5p in 1α,25-dihydroxy-VD₃ (1,25D3) mediating the regulation of the TBK1/IRF3 signaling pathway. (3) Results: A 5000 IU·kg^–1 dietary VD₃ supplementation attenuated RV-induced the decrease of the villus height and crypt depth (p < 0.05), and up-regulated TBK1, IRF3, and IFN-β mRNA expressions in the jejunum (p < 0.05). Incubation with 1,25D3 significantly decreased the RV mRNA expression and the RV antigen concentration, and increased the TBK1 mRNA and protein levels, and the phosphoprotein IRF3 (p-IRF3) level (p < 0.05). The expression of miR-155-5p was up-regulated in response to an RV infection in vivo and in vitro (p < 0.05). 1,25D3 significantly repressed the up-regulation of miR-155-5p in vivo and in vitro (p < 0.05). Overexpression of miR-155-5p remarkably suppressed the mRNA and protein levels of TBK1 and p-IRF3 (p < 0.01), while the inhibition of miR-155-5p had an opposite effect. Luciferase activity assays confirmed that miR-155-5p regulated RV replication by directly targeting TBK1, and miR-155-5p suppressed the TBK1 protein level (p < 0.01). (4) Conclusions: These results indicate that miR-155-5p is involved in 1,25D3 mediating the regulation of the TBK1/IRF3 signaling pathway by directly targeting TBK1.

Impact of Micronutrients on the Immune Response of Animals

Vitamins and minerals (micronutrients) play an important role in regulating and shaping an immune response. Deficiencies generally result in inadequate or dysregulated cellular activity and cytokine expression, thereby affecting the immune response. Decreased levels of natural killer, granulocyte, and phagocytic cell activity and T and B cell proliferation and trafficking are associated with inadequate levels of micronutrients, as well as increased susceptibility to various adverse health conditions, including inflammatory disorders, infection, and altered vaccine efficacy. In addition, most studies of micronutrient modulation of immune responses have been done in rodents and humans, thus limiting application to the health and well-being of livestock and companion animals. This exploratory review elucidates the role of vitamins and minerals on immune function and inflammatory responses in animals (pigs, dogs, cats, horses, goats, sheep, and cattle), with reference to rodents and humans.

Dietary vitamin D3 supplementation protects laying hens against lipopolysaccharide-induced immunological stress

Background

The effects of vitamin D on the immune function of laying hens are not well understood. This study investigated the effects of vitamin D₃ (VD₃) on laying performance and immunological functions in laying hens under Escherichia coli lipopolysaccharide (LPS) challenge.

Methods

In experiment one, 360 Jinghong-1 strain layers (32 weeks) were randomly divided into four groups with six replicates per group and 15 hens per replicate. Hens were fed a basal diet supplemented with different levels of VD₃ (0; 500; 1500; or 3000 IU VD₃/kg of diet) for 10 weeks to determine laying performance, egg quality, and other parameters. In experiment two, 24 Jinghong laying hens (32 weeks) were fed basal diets with either 0 or 3000 IU VD₃/kg of diet. After 10 weeks of feeding, six hens from each treatment were injected intravenously with 8 mg/kg of body weight of either LPS or saline. Blood and spleen samples were obtained for immune parameter analysis 4 h after injection.

Results

VD₃ deficiency reduced egg production and egg quality; in addition, feed intake and feed-to-egg ratio increased. No significant differences were observed in these parameters except eggshell strength between dietary VD₃ supplemental levels at 500; 1500; and 3000 IU VD₃/kg of diet. VD₃ deficiency increased serum hormone (calcitonin, parathyroid hormone, estradiol, and progesterone) and cytokine (IL-6, IL-10) levels, the ratio of IFN-γ to IL-4, myeloperoxidase activity and total IgG content in the serum, and upregulated the blood CD3⁺ T cell population. Splenic retinoid X receptor (RXR), nuclear factor-κB (NF-κB), inducible nitric oxide synthase (iNOS), and polymeric immunoglobulin receptor (pIgR) gene mRNA levels were upregulated in VD₃-deficienct hens. VD₃ deficiency significantly reduced serum Follicle stimulating hormone (FSH) and Luteinizing hormone (LH) concentrations and the number of CD4⁺CD25⁺ T cells in the blood. These changes were completely normalized by VD₃ sufficiency. LPS reduced serum LH concentration, splenic lysozyme, and pIgR gene mRNA levels. LPS induced an increase in total serum IgM levels and the percentage of CD8⁺ T cells in the blood. The changes were completely reversed by VD₃ addition.

Conclusion

VD₃ supplementation could protect laying hens not only from VD₃ deficiency but also from immunological stress.

l-Isoleucine Administration Alleviates Rotavirus Infection and Immune Response in the Weaned Piglet Model

Rotavirus (RV) infection is one of the main pathogenic causes of severe gastroenteritis and diarrhea in infants and young animals. This study aimed to determine how dietary l-isoleucine supplementation improves the growth performance and immune response in weaned piglets with RV infection. In cell culture experiment, after IPEC-J2 and 3D4/31 cells were treated by 8 mM l-isoleucine for 24 h, the gene expressions of β-defensins and pattern recognition receptors (PRR) signaling pathway were significantly increased. Then, in the in vivo experiment, 28 crossbred weaned pigs were randomly divided into two groups fed with basal diet with or without l-isoleucine for 18 days. On the 15th day, the oral RV gavage was executed in the half of piglets. Average daily feed intake and gain of piglets were impaired by RV infection (P < 0.05). RV infection also induced severe diarrhea and the increasing serum urea nitrogen concentration (P < 0.05), and decreased CD4+ lymphocyte and CD4+/CD8+ ratio of peripheral blood (P < 0.05). However, dietary l-isoleucine supplementation attenuated diarrhea and decreasing growth performance (P < 0.05), decreased the NSP4 concentration in ileal mucosa, and enhanced the productions and/or expressions of immunoglobulins, RV antibody, cytokines, and β-defensins in serum, ileum, and/or mesenteric lymph nodes of weaned piglets (P < 0.05), which could be relative with activation of PRR signaling pathway and the related signaling pathway (P < 0.05) in the weaned pigs orally infused by RV. These results indicate that dietary l-isoleucine could improve the growth performance and immune function, which could be derived from l-isoleucine treatment improving the innate and adaptive immune responses via activation of PRR signaling pathway in RV-infected piglets. It is possible that l-isoleucine can be used in the therapy of RV infection in infants and young animals.

High Throughput Screening for Natural Host Defense Peptide-Inducing Compounds as Novel Alternatives to Antibiotics

A rise in antimicrobial resistance demands novel alternatives to antimicrobials for disease control and prevention. As an important component of innate immunity, host defense peptides (HDPs) are capable of killing a broad spectrum of pathogens and modulating a range of host immune responses. Enhancing the synthesis of endogenous HDPs has emerged as a novel host-directed antimicrobial therapeutic strategy. To facilitate the identification of natural products with a strong capacity to induce HDP synthesis, a stable macrophage cell line expressing a luciferase reporter gene driven by a 2-Kb avian β-defensin 9 (AvBD9) gene promoter was constructed through lentiviral transduction and puromycin selection. A high throughput screening assay was subsequently developed using the stable reporter cell line to screen a library of 584 natural products. A total of 21 compounds with a minimum Z-score of 2.0 were identified. Secondary screening in chicken HTC macrophages and jejunal explants further validated most compounds with a potent HDP-inducing activity in a dose-dependent manner. A follow-up oral administration of a lead natural compound, wortmannin, confirmed its capacity to enhance the AvBD9 gene expression in the duodenum of chickens. Besides AvBD9, most other chicken HDP genes were also induced by wortmannin. Additionally, butyrate was also found to synergize with wortmannin and several other newly-identified compounds in AvBD9 induction in HTC cells. Furthermore, wortmannin acted synergistically with butyrate in augmenting the antibacterial activity of chicken monocytes. Therefore, these natural HDP-inducing products may have the potential to be developed individually or in combinations as novel antibiotic alternatives for disease control and prevention in poultry and possibly other animal species including humans.

Dietary modulation of endogenous host defense peptide synthesis as an alternative approach to in-feed antibiotics

Traditionally, antibiotics are included in animal feed at subtherapeutic levels for growth promotion and disease prevention. However, recent links between in-feed antibiotics and a rise in antibiotic-resistant pathogens have led to a ban of all antibiotics in livestock production by the European Union in January 2006 and a removal of medically important antibiotics in animal feeds in the United States in January 2017. An urgent need arises for antibiotic alternatives capable of maintaining animal health and productivity without triggering antimicrobial resistance. Host defense peptides (HDP) are a critical component of the animal innate immune system with direct antimicrobial and immunomodulatory activities. While in-feed supplementation of recombinant or synthetic HDP appears to be effective in maintaining animal performance and alleviating clinical symptoms in the context of disease, dietary modulation of the synthesis of endogenous host defense peptides has emerged as a cost-effective, antibiotic-alternative approach to disease control and prevention. Several different classes of small-molecule compounds have been found capable of promoting HDP synthesis. Among the most efficacious compounds are butyrate and vitamin D. Moreover, butyrate and vitamin D synergize with each other in enhancing HDP synthesis. This review will focus on the regulation of HDP synthesis by butyrate and vitamin D in humans, chickens, pigs, and cattle and argue for potential application of HDP-inducing compounds in antibiotic-free livestock production.

Differences of Rotavirus Vaccine Effectiveness by Country: Likely Causes and Contributing Factors

Rotaviruses are a major cause of acute gastroenteritis in infants and young children worldwide and in many other mammalian and avian host species. Since 2006, two live-attenuated rotavirus vaccines, Rotarix^® and RotaTeq^®, have been licensed in >100 countries and are applied as part of extended program of vaccination (EPI) schemes of childhood vaccinations. Whereas the vaccines have been highly effective in high-income countries, they were shown to be considerably less potent in low- and middle-income countries. Rotavirus-associated disease was still the cause of death in >200,000 children of <5 years of age worldwide in 2013, and the mortality is concentrated in countries of sub-Saharan Africa and S.E. Asia. Various factors that have been identified or suggested as being involved in the differences of rotavirus vaccine effectiveness are reviewed here. Recognition of these factors will help to achieve gradual worldwide improvement of rotavirus vaccine effectiveness.

Dietary apple pectic oligosaccharide improves gut barrier function of rotavirus-challenged weaned pigs by increasing antioxidant capacity of enterocytes

Rotavirus can lead to decreasing gut barrier function and diarrhea of children and young animals. Apple pectic oligosaccharide treatment reduced diarrhea in rotavirus-infected piglets. This study was conducted to explore whether apple pectic oligosaccharide administration could protect gut barrier function of piglets against rotavirus infection. A total of 28 crossbred weaned barrows were allotted into 2 treatments fed the diets supplementing 0 and 200 mg/kg apple pectic oligosaccharide. Half of pigs in each diet treatment were challenged by rotavirus on d 15. The whole duration of this experiment is 18 days. Rotavirus challenge increased average diarrhea index, and impaired microbiota in cecal digesta, and histology, expressions of tight-junction proteins, mucins and glucagon like peptide-2 concentrations, antioxidant capacity, endoplasmic reticulum stress, autophagy and apoptosis in jejunal mucosa of piglets. However, dietary apple pectic oligosaccharide supplementation relieved effects of rotavirus challenge on diarrhea, gut health, and antioxidant capacity, endoplasmic reticulum stress, autophagy and apoptosis of jejunal mucosa in piglets. These results suggest that apple pectic oligosaccharide administration can prevent diarrhea and damage of gut barrier function via improving antioxidant capacity that might reduce endoplasmic reticulum stress, autophagy and apoptosis of intestinal epithelial cells in rotavirus-infected piglets.

Dietary Pectic Oligosaccharide Administration Improves Growth Performance and Immunity in Weaned Pigs Infected by Rotavirus

Rotavirus infection is one of the main pathogenic causes of gastroenteritis and diarrhea in children and young animals. The present study aimed to determine whether dietary pectic oligosaccharide (POS) supplementation could improve the growth performance and immunity in weaned pigs infected by porcine rotavirus (PRV). Twenty-eight crossbred weaned galts were randomly divided into two groups fed basal diet with or without POS for 18 days. On the 15th day, PRV was orally infused to half of the pigs. ADFI, ADG, and F/G ratio were impaired by PRV infection in weaned pigs (P < 0.05). PRV challenge also induced diarrhea and enhanced serum levels of urea nitrogen (P < 0.05), MDA (P < 0.05), IgA (P < 0.05), and IgG (P = 0.08), rotavirus antibody levels in serum, jejunal, and ileal mucosa (P < 0.05), and IL-2 levels in the jejunal (P = 0.07) and ileal (P = 0.08) mucosa, but decreased digestive enzyme activities of the jejunal digesta (P < 0.05) and concentrations of sIgA, IL-4, and IFN-γ in the jejunal and ileal mucosa (P < 0.05) and serum T-AOC (P < 0.05) in the weaned pigs. POS administration could improve the growth performance of the weaned pigs (P < 0.05) and enhance the serum IgA level (P < 0.05), the lipase and tryptase activities of jejunal digesta (P < 0.05), and the sIgA, IL-4, and IFN-γ levels of jejunal and/or ileal mucosa (P < 0.05) in the weaned pigs. Furthermore, supplementing POS in diets could alleviate diarrhea and decreased growth performance in the weaned pigs orally infused by PRV (P < 0.05), increase serum, jejunal, and ileal rotavirus antibody levels (P < 0.05) and attenuate the effect of PRV challenge on serum T-AOC and concentrations of IgG and MDA (P < 0.05), lipase and tryptase activities in jejunal digesta (P < 0.05), and sIgA, IL-4, and IFN-γ levels in jejunal and/or ileal mucosa (P < 0.05) in the weaned pigs. These results suggest that dietary POS supplementation could improve growth performance, which was possibly because POS administration improved the immune function and the utilization of nutrients in the PRV-infected piglets. This offers a potential dietary intervention strategy against intestinal exposure to rotavirus in piglets.

Intestinal microbiota could transfer host Gut characteristics from pigs to mice

BACKGROUND

The present study was conducted to compare the differences in gut microbiota composition and gut-phenotypes among pig breeds, and determine whether these differences would transmit to mice colonized with fecal microbiota of different pig breeds. A total of 24 1-day-old germ-free BALB/C mice were divided into 3 groups (TFM, YFM and RFM), which were transplanted with intact fecal microbiota of Tibetan pig (TP), Yorkshire pig (YP) and Rongchang pig (RP), respectively.

RESULTS

Results showed that different pig breeds exhibited distinct gut microbiota profile based on high-throughput pyrosequencing. YP exhibited a lower Firmicutes/Bacteroidetes ratio and apparent genera differences compared with RP and TP, and higher levels of bacteria from Spirochaetes were observed in TP compared with RP and YP (P < 0.05). Transplanted porcine microbiota into GF mice replicated the phenotypes of pig donors. Moreover, the three groups of donor pigs and their mice recipients exhibited different intestinal index and morphology. TP and RP had higher intestinal weight and relative CDX2 mRNA expression in ileum than YP, and longer intestine, higher villus height of duodenum and jejunum were observed in TP compared with YP and RP (P < 0.05). TP exhibited higher GLP-2 mRNA expression in duodenum and jejunum than RP (P < 0.05). Similarly, YFM had lower intestine weight and CDX2 mRNA expression in ileum than TFM and RFM (P < 0.05). The intestine length in TFM was longer than that in RFM, and TFM had higher villus height in duodenum and jejunum and GLP-2 mRNA expression in ileum than the other two groups (P < 0.05). Besides, the digestive and absorptive ability was different among the three groups in donor pigs and mice recipients. YP had higher jejunal lactase and maltase activities than TP and RP, while TP had higher activities of jejunal ATPase, γ-GT, and relative SGLT1 mRNA expression in duodenum and jejunum than YP and RP (P < 0.05). Likewise, YFM had higher jejunal sucrase and maltase activities than TFM and RFM, whereas higher jejunal γ-GT activity and relative SGLT1 mRNA expression in duodenum and ileum were observed in TFM compared with YFM and RFM (P < 0.05). In addition, Tibetan pigs-derived microbiota improved gut barrier in mice recipients. The concentration of MDA in YP was higher than that in TP and RP (P = 0.078), and the relative ZO-1 mRNA expression in ileum in TP was higher than that in YP (P < 0.05). Likely, compared with TFM and RFM, YFM exhibited increasing MDA concentration in jejunum (P = 0.098), and the relative ZO-1 mRNA expression in duodenum and ileum in TFM were higher than that in YFM (P < 0.05).

CONCLUSIONS

There were huge differences in gut microbiota composition and gut characteristics among pig breeds, and gut microbiota could partially convey host gut characteristics from pigs to mice.

Is there a relationship between low vitamin D and rotaviral diarrhea?

BACKGROUND

For children under 5 years of age, 1700 000 000 episodes of diarrhea are seen worldwide, and death occurs in 700 000 of these cases due to diarrhea. Rotavirus is an important cause of diarrhea in this age group, and many studies have shown that vitamin D plays a pivotal role in the immune system, as well as in antimicrobial peptide gene expression. In addition, lower vitamin D has been correlated with higher rates of infectious diseases such as respiratory tract infection, tuberculosis, and viral infection.

METHODS

Seventy patients with rotaviral diarrhea and 67 healthy patients were enrolled in this study. Serum 25-hydroxy vitamin D(3) (25(OH)D(3)), parathormone, calcium, phosphate, alkaline phosphatase, complete blood count parameters, and C-reactive protein were compared between pre-school children hospitalized due to rotaviral diarrhea and healthy children. Additionally, birthweight, feeding habits in the first 6 months of life, vitamin D and multivitamin supplements, and rotaviral vaccinations were also evaluated in each group.

RESULTS

There were no differences between the groups with regard to gender and age, but 25(OH)D(3) was significantly different: 14.6 ± 8.7 ng/mL in the rotaviral diarrhea patients versus 29.06 ± 6.51 ng/mL in the health controls (P < 0.001), and serum 25(OH)D(3) <20 ng/mL (OR, 6.3; 95%CI: 3.638-10.909; P < 0.001) was associated with rotaviral diarrhea.

CONCLUSIONS

Low vitamin D is associated with rotaviral diarrhea. This is the first study in the literature to show this, and this result needs to be repeated in larger controlled clinical studies.

Vitamin D inhibits lipopolysaccharide-induced inflammatory response potentially through the Toll-like receptor 4 signalling pathway in the intestine and enterocytes of juvenile Jian carp (Cyprinus carpio var. Jian)

The present study was conducted to investigate the anti-inflammatory effect of vitamin D both in juvenile Jian carp (Cyprinus carpio var. Jian) in vivo and in enterocytes in vitro. In primary enterocytes, exposure to 10 mg lipopolysaccharide (LPS)/l increased lactate dehydrogenase activity in the culture medium (P<0·05) and resulted in a significant loss of cell viability (P<0·05). LPS exposure increased (P<0·05) the mRNA expression of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6 and IL-8), which was decreased by pre-treatment with 1,25-dihydroxyvitamin D (1,25D3) in a dose-dependent manner (P<0·05). Further results showed that pre-treatment with 1,25D3 down-regulated Toll-like receptor 4 (TLR4), myeloid differentiation primary response gene 88 (Myd88) and NF-κB p65 mRNA expression (P<0·05), suggesting potential mechanisms against LPS-induced inflammatory response. In vivo, intraperitoneal injection of LPS significantly increased TNF-α, IL-1β, IL-6 and IL-8 mRNA expression in the intestine of carp (P<0·05). Pre-treatment of fish with vitamin D3 protected the fish intestine from the LPS-induced increase of TNF-α, IL-1β, IL-6 and IL-8 mainly by downregulating TLR4, Myd88 and NF-κB p65 mRNA expression (P<0·05). These observations suggest that vitamin D could inhibit LPS-induced inflammatory response in juvenile Jian carp in vivo and in enterocytes in vitro. The anti-inflammatory effect of vitamin D is mediated at least in part by TLR4-Myd88 signalling pathways in the intestine and enterocytes of juvenile Jian carp.

Dietary Leucine Supplementation Improves the Mucin Production in the Jejunal Mucosa of the Weaned Pigs Challenged by Porcine Rotavirus

The present study was mainly conducted to determine whether dietary leucine supplementation could attenuate the decrease of the mucin production in the jejunal mucosa of weaned pigs infected by porcine rotavirus (PRV). A total of 24 crossbred barrows weaned at 21 d of age were assigned randomly to 1 of 2 diets supplemented with 1.00% L-leucine or 0.68% L-alanine (isonitrogenous control) for 17 d. On day 11, all pigs were orally infused PRV or the sterile essential medium. During the first 10 d of trial, dietary leucine supplementation could improve the feed efficiency (P = 0.09). The ADG and feed efficiency were impaired by PRV infusion (P<0.05). PRV infusion also increased mean cumulative score of diarrhea, serum rotavirus antibody concentration and crypt depth of the jejunal mucosa (P<0.05), and decreased villus height: crypt depth (P = 0.07), goblet cell numbers (P<0.05), mucin 1 and 2 concentrations (P<0.05) and phosphorylated mTOR level (P<0.05) of the jejunal mucosa in weaned pigs. Dietary leucine supplementation could attenuate the effects of PRV infusion on feed efficiency (P = 0.09) and mean cumulative score of diarrhea (P = 0.09), and improve the effects of PRV infusion on villus height: crypt depth (P = 0.06), goblet cell numbers (P<0.05), mucin 1 (P = 0.08) and 2 (P = 0.07) concentrations and phosphorylated mTOR level (P = 0.08) of the jejunal mucosa in weaned pigs. These results suggest that dietary 1% leucine supplementation alleviated the decrease of mucin production and goblet cell numbers in the jejunal mucosa of weaned pigs challenged by PRV possibly via activation of the mTOR signaling.