[The One Health approach in the context of global commodity chains, crises, and food and feed safety]. / Das One-Health-Konzept im Kontext globaler Warenketten, Krisen und der Sicherheit von Lebens- und Futtermitteln.

The holistic view of food and feed safety, including animal health and environmental conditions, is an important pillar of the One Health approach. The terminology thus clearly goes beyond the prevention of spreading microbiological diseases, in which context it is often understood, and highlights that humans, animals, and the environment as well as their interaction should be considered in a transdisciplinary context.In terms of One Health, this discussion paper focuses less on microbiological risks, but rather on the connection to chemical risks in the food chain. This is illustrated by concrete examples of chemical contaminants (metals, persistent organic contaminants, natural toxins). The mechanisms of input and transfer along the food chain are presented.Minimizing the presence of contaminants and thus exposure requires international and interdisciplinary cooperation in the spirit of the One Health approach. Climate change, pandemics, shortages of raw materials, energy deficiencies, political crises, and environmental disasters can affect the entire food chain from primary production of plant and animal foods to further processing and provision of products to consumers. In addition to changing availability, this can also have an impact on the composition, quality, and safety of food and feed. Based on the effect on global commodity chains, vulnerable and resilient areas along the food chain become visible. In terms of the One Health approach, the aim is to increase safety and resilience along the food chain and to minimize its vulnerability.

Long-term dietary exposure to copper in the population in Germany - Results from the BfR MEAL study.

The German Total Diet Study (BfR MEAL Study) measured copper in 356 foods. In 105 of these foods copper was determined separately for conventionally and organically pooled samples. Mammalian liver, nuts, oilseeds, cocoa powder and chia seeds contained the highest copper levels. Organically produced foods tended to have higher levels compared to conventionally produced foods. Children's copper exposure was between 0.04 mg/kg body weight per day (mg/kg bw/day) and 0.07 mg/kg bw/day (median). High exposure (95th percentile) ranged between 0.07 mg/kg bw/day and 0.11 mg/kg bw/day. Adult's exposure ranged between 0.02 mg/kg bw/day (median) and 0.04 mg/kg bw/day (95th percentile). Grains and grain-based products were main contributors for all age groups. Copper intake was about 10% higher in a scenario where consumers select the organically produced variants. Children's median and high exposure was above the acceptable daily intake (ADI) of 0.07 mg/kg bw/day set by the European Food Safety Authority (EFSA). However, according to EFSA's evaluation this is not of concern due to higher requirement related to growth. For adults, frequent consumers of mammalian liver exceeded the ADI in median and 95th percentile. Intake of copper-containing dietary supplements may also lead to exceedance of the ADI in all age groups.

Dietary methionine source alters the lipidome in the small intestinal epithelium of pigs.

Methionine (Met) as an essential amino acid has key importance in a variety of metabolic pathways. This study investigated the influence of three dietary Met supplements (0.21% L-Met, 0.21% DL-Met and 0.31% DL-2-hydroxy-4-(methylthio)butanoic acid (DL-HMTBA)) on the metabolome and inflammatory status in the small intestine of pigs. Epithelia from duodenum, proximal jejunum, middle jejunum and ileum were subjected to metabolomics analysis and qRT-PCR of caspase 1, NLR family pyrin domain containing 3 (NLRP3), interleukins IL1ß, IL8, IL18, and transforming growth factor TGFß. Principal component analysis of the intraepithelial metabolome revealed strong clustering of samples by intestinal segment but not by dietary treatment. However, pathway enrichment analysis revealed that after L-Met supplementation polyunsaturated fatty acids (PUFA) and tocopherol metabolites were lower across small intestinal segments, whereas monohydroxy fatty acids were increased in distal small intestine. Pigs supplemented with DL-HMTBA showed a pronounced shift of secondary bile acids (BA) and sphingosine metabolites from middle jejunum to ileum. In the amino acid super pathway, only histidine metabolism tended to be altered in DL-Met-supplemented pigs. Diet did not affect the expression of inflammation-related genes. These findings suggest that dietary supplementation of young pigs with different Met sources selectively alters lipid metabolism without consequences for inflammatory status.

[Chronic oversupply with copper as a potential herd health problem on a German dairy farm - Diagnostic value of different sample types for assessment of copper supply in dairy cows]. / Chronische Kupferüberversorgung als mögliches Bestandsproblem in einer deutschen Milchviehherde.

In contrast to sheep, chronic copper oversupply or toxicity represent infrequent events in cattle. This case report describes a chronically elevated exposure to copper arising from excessive supplementation of mineral feedstuff leading to a herd health problem in a German Holstein dairy herd. For diagnosis on herd level, 10 cows of both the close-up (VB) and high-yielding (HL) groups were selected and blood as well as urine samples were collected. Clinical chemistry investigation of these samples only revealed slightly raised activities of liver enzymes in cows of the HL group. Analysis of the total mixed ration (TMR) of both groups revealed a significant oversupply with copper, zinc, cobalt, and selenium. On the basis of these findings, the copper content of urine, feces, pigmented hair as well as plasma ceruloplasmin activity were measured additionally. Liver biopsies were performed in cows of the HL group and in heifers, the latter of which had received a mineral feed for young cattle according to the manufacturer's instructions. Results indicated increased fecal copper in both HL and VB groups as well as above normal or high-normal values of hepatic copper and cobalt resp. selenium, zinc, and manganese in the HL cows. In contrast, heifers had physiological amounts of trace elements in their liver tissues. This report demonstrates the suitability of fecal analysis and TMR for a reliable assessment of copper supply, while blood, urine, and hair failed to represent appropriate sample types. In order to attain a dependable diagnosis of potential copper oversupply, a liver biopsy - which may also be performed in buiatric practice - is deemed necessary.

Concentration and chemical form of dietary zinc shape the porcine colon microbiome, its functional capacity and antibiotic resistance gene repertoire.

Despite a well-documented effect of high dietary zinc oxide on the pig intestinal microbiota composition less is it yet known about changes in microbial functional properties or the effect of organic zinc sources. Forty weaning piglets in four groups were fed diets supplemented with 40 or 110 ppm zinc as zinc oxide, 110 ppm as Zn-Lysinate, or 2500 ppm as zinc oxide. Host zinc homeostasis, intestinal zinc fractions, and ileal nutrient digestibility were determined as main nutritional and physiological factors putatively driving colon microbial ecology. Metagenomic sequencing of colon microbiota revealed only clear differences at genus level for the group receiving 2500 ppm zinc oxide. However, a clear group differentiation according to dietary zinc concentration and source was observed at species level. Functional analysis revealed significant differences in genes related to stress response, mineral, and carbohydrate metabolism. Taxonomic and functional gene differences were accompanied with clear effects in microbial metabolite concentration. Finally, a selection of certain antibiotic resistance genes by dietary zinc was observed. This study sheds further light onto the consequences of concentration and chemical form of dietary zinc on microbial ecology measures and the resistome in the porcine colon.

Dietary Supplementation of dl-Methionine Potently Induces Sodium-Dependent l-Methionine Absorption in Porcine Jejunum Ex Vivo.

BACKGROUND: Methionine is an essential amino acid (AA) with many fundamental roles. Humans often supplement l-Met, whereas dl-Met and dl-2-hydroxy-4-(methylthio)butanoic acid (dl-HMTBA) are more frequently used to supplement livestock. OBJECTIVES: The study aimed to investigate whether dietary Met source alters the absorptive capacity for Met isomers in the small intestine of piglets. METHODS: A total of 27 male 10-wk-old piglets in 3 feeding groups received a diet supplemented with 0.21% dl-Met, 0.21% l-Met, or 0.31% dl-HMTBA to meet the Met + cystine requirement. After ≥10 d, absorptive fluxes of d-Met or l-Met were measured at a physiological concentration of 50 µM and a high concentration of 5 mM in duodenum, middle jejunum, and ileum ex vivo. Data were compared by 2-factor ANOVA. RESULTS: Across diets, fluxes of both Met isomers at both tested concentrations increased from duodenum to ileum by a factor of ∼2-5.5 (P < 0.05). Pigs supplemented with dl-Met had greater (P < 0.085) absorptive fluxes at 50 µM l-Met (0.50, 2.07, and 3.86 nmol · cm-2 · h-1) and d-Met (0.62, 1.41, and 1.19 nmol · cm-2 · h-1) than did pigs supplemented with dl-HMTBA (l-Met: 0.28, 0.76, and 1.08 nmol · cm-2 · h-1; d-Met: 0.34, 0.58, and 0.64 nmol · cm-2 · h-1) in duodenum, jejunum, and ileum, respectively. Only in jejunum of dl-Met-fed pigs, fluxes at 50 µM l-Met were reduced by the omission of luminal Na+ (from 3.27 to 0.86 nmol · cm-2 · h-1; P < 0.05) and by a cocktail of 22 luminal AAs (to 1.05 nmol · cm-2 · h-1; P < 0.05). CONCLUSIONS: Dietary supplementation of dl-Met increases the efficiency of l-Met and d-Met absorption at physiologically relevant luminal Met concentrations along the small intestine of pigs, including a very prominent induction of an Na+-dependent transport system with preference for l-Met in the mid-jejunum. Dietary supplementation with dl-Met could be a promising tool to improve the absorption of Met and other AAs.

Zinc prevents intestinal epithelial barrier dysfunction induced by alpha-hemolysin-producing Escherichia coli 536 infection in porcine colon.

Zinc treatment is beneficial for infectious diarrhea or colitis. This study aims to characterize the pathomechanisms of the epithelial barrier dysfunction caused by alpha-hemolysin (HlyA)-expressing Escherichia coli in the colon mucosa and the mitigating effects of zinc ions. We performed Ussing chamber experiments on porcine colon epithelium and infected the tissues with HlyA-producing E. coli. Colon mucosa from piglets was obtained from a feeding trial with defined normal or high dose zinc feeding (pre-conditioning). Additional to the zinc feeding, zinc was added to the luminal compartment of the Ussing chamber. Transepithelial electrical resistance (TER) was measured during the infection of the living tissue and subsequently the tissues were immuno-stained for confocal microscopy. Zinc applied to the luminal compartment was effective in preventing from E. coli-induced epithelial barrier dysfunction in Ussing chamber experiments. In contrast, zinc pre-conditioning of colon mucosae when zinc ions were missing subsequently in the luminal compartment was not sufficient to prevent epithelial barrier impairment during E. coli infection. The pathological changes caused by E. coli HlyA were alterations of tight junction proteins claudin-4 and claudin-5, focal leak formation, and cell exfoliation which reflected the paracellular barrier defect measured by a reduced TER. In microscopic analysis of luminal zinc-treated mucosae these changes were absent. In conclusion, continuous presence of unbound zinc ions in the luminal compartment is essential for the protective action of zinc against E. coli HlyA. This suggests the usage of zinc as therapeutic regimen, while prophylactic intervention by high dietary zinc loads may be less useful.

Effects of dietary menthol-rich bioactive lipid compounds on zootechnical traits, blood variables and gastrointestinal function in growing sheep.

BACKGROUND: The present study aimed at investigating the influence of 90% menthol-containing plant bioactive lipid compounds (PBLC, essential oils) on growth performance, blood haematological and biochemical profile, and nutrient absorption in sheep. Twenty-four growing Suffolk sheep were allotted into three dietary treatments: Control (without PBLC), lower dose of PBLC (PBLC-L; 80 mg/d) and higher dose of PBLC (PBLC-H; 160 mg/d). Sheep in all groups were fed meadow hay ad libitum plus 600 g/d of concentrate pellets for 28 d. RESULTS: Average daily gain was not affected by treatment. Feeding of PBLC increased hay and total feed intake per kg body weight (P < 0.05). Counts of total leucocytes, lymphocytes and monocytes were not different among treatments. However, neutrophil count decreased (P < 0.05) in PBLC-H with a similar trend in PBLC-L (P < 0.10). Concentrations of glucose, bilirubin, triglycerides, cholesterol, urea and magnesium in serum were not different among sheep fed different doses of PBLC. However, serum calcium concentration tended to increase in PBLC-H (P < 0.10) and serum concentrations of aspartate & asparagine (P < 0.01) and glutamate & glutamine (P < 0.05) increased linearly with increasing PBLC dose. In ruminal epithelia isolated from the rumen after killing, baseline conductance (G t; P < 0.05) and short-circuit current (I sc; P < 0.01) increased in both PBLC groups. Ruminal uptakes of glucose and methionine in the presence of Na+ were not affected by the dietary PBLC supplementation. In the absence of Na+, however, glucose and methionine uptakes increased (P < 0.05) in PBLC-H. In the jejunum, I sc tended to increase in PBLC-H (P < 0.10), but baseline G t was not affected. Intestinal uptakes of glucose and methionine were not influenced by PBLC in the presence or absence of Na+. CONCLUSION: The results suggest that menthol-rich PBLC increase feed intake, and passive ion and nutrient transport, the latter specifically in the rumen. They also increased serum concentrations of urea precursor amino acids and tended to increase serum calcium concentrations. Future studies will have to show whether some of these findings might be commonly linked to a stimulation of transient receptor potential (TRP) channels in the gastrointestinal tract.

High dosage of zinc modulates T-cells in a time-dependent manner within porcine gut-associated lymphatic tissue.

Zn serves as a powerful feed additive to reduce post-weaning diarrhoea in pigs. However, the mechanisms responsible for Zn-associated effects on the adaptive immune responses following feeding of a very high dosage of Zn remain elusive. In this study, we examined the T-cell response in gut-associated lymphatic tissues of seventy-two weaned piglets. Piglets received diets with 57 mg Zn/kg (low Zn concentration, LZn), 164 mg Zn/kg (medium Zn concentration, MZn) or 2425 mg Zn/kg (high Zn concentration, HZn) mg Zn/kg feed for 1, 2 or 4 weeks. We observed that feeding the HZn diet for 1 week increased the level of activated T-helper cells (CD4+ and CD8α dim) compared with feeding MZn and LZn (P<0·05). In addition, we observed higher transcript amounts of interferon γ and T-box 21 (TBET) in the HZn group compared with the MZn and LZn groups (P<0·05). A gene set enrichment analysis revealed an over-representation of genes associated with 'cytokine signalling in immune system'. Remarkably, feeding of a very high Zn dosage led to a switch in the immune response after 2 weeks. We detected higher relative cell counts of CD4+CD25high regulatory T-helper cells (P<0·05) and a higher expression of forkhead box P3 (FOXP3) transcripts (P<0·05). After 4 weeks of feeding a high-dosage Zn diet, the relative CD4+ T-cell count (P<0·05) and the relative CD8ß + T-cell count (P<0·1) were reduced compared with the MZn group. We hypothesise that after 1 week the cellular T-helper 1 response is switched on and after 2 weeks it is switched off, leading to decreased numbers of T-cells.

[Selenium deficiency in an organic extensive water buffalo farm]. / Selenmangel als Bestandsproblem in einer ökologisch extensiven Wasserbüffelhaltung.

This case report presents investigations of muscle problems in three male water buffaloes (1-2 years) kept extensively (loose housing, pasture). The bulls were presented because of listlessness and increased lying periods. They displayed difficulties to stand up, a stilted gait, and tremor in the legs. The determination of the selenium concentration by the measurement of glutathione peroxidase activity in whole blood samples (EDTA) demonstrated selenium deficiency in all three buffaloes. This confirmed the tentative diagnosis of nutritive myodystrophy due to selenium deficiency. Following a single injection of 1500 mg all-rac-alpha-tocopherol acetate and 11 mg sodium selenite, the bulls recovered clinically. The whole blood samples taken subsequently from seven adult water buffaloes on the farm showed selenium deficiency in all animals. Consequently, slow-release multi-trace element boluses were administered once orally - as far as possible - to all adult animals of the herd. After 1 year, a good to very good selenium supply was observed in all these buffaloes, except for one cow, in which bolus application had failed.

Zinc treatment is efficient against Escherichia coli α-haemolysin-induced intestinal leakage in mice.

Zinc homoeostasis exerts protective effects in inflammatory intestinal diseases and zinc supplementation has been successfully used for treating infectious diarrhoea. This study aimed at a characterisation of zinc effects on focal leak induction by α-haemolysin (HlyA)-producing Escherichia coli (E. coli) as protective mechanism for colitis. We conducted in vivo experiments by oral challenge of gnotobiotic mice colonised with HlyA-expressing E. coli-536. Mice were either fed a defined normal or high zinc diet to analyse effects of zinc as a therapeutic regimen. HlyA-deficient E. coli-536 mutants were used as controls. Mice infected with HlyA-producing E. coli showed impaired barrier integrity when receiving normal zinc. High zinc supplementation in HlyA-producing E. coli-infected mice reduced epithelial dysfunction as indicated by ameliorated macromolecule permeability. Reduced size of focal leaks with diminished bacterial translocation was observed as inherent mechanisms of this zinc action. In human colon cell monolayers application of zinc rescued the HlyA-dependent decline in transepithelial electrical resistance via reduction of the calcium entry into HlyA-exposed cells. Calcium-dependent cell exfoliation was identified as mechanism for focal leak induction. In conclusion, zinc supplementation protects from HlyA-induced barrier dysfunction in vivo and in vitro, providing an explanation for the protective efficacy of zinc in intestinal disorders.

Regulation of intracellular Zn homeostasis in two intestinal epithelial cell models at various maturation time points.

After weaning, piglets are often fed diets supplemented with high concentrations of zinc (Zn) to decrease post-weaning diarrhea. The aim of this study was to elucidate the regulation of Zn homeostasis within intestinal epithelial cells during excessive Zn exposure. High Zn concentrations elevated the intracellular Zn level in IPEC-J2 and Caco-2 cells which was influenced by differentiation status and time of exposure. With increasing Zn concentrations, mRNA and protein levels of metallothionein (MT) and zinc transporter 1 (ZnT1) were upregulated, whereas zinc transporter 4 (ZIP4) expression was downregulated. Metal-regulatory transcription factor-1 (MTF1) mRNA expression was upregulated at high Zn concentrations in IPEC-J2 cells, which corresponded to higher intracellular Zn concentrations. Based on these results, we suggest that intestinal epithelial cells adapt the expression of these genes to the amount of extracellular Zn available in order to maintain Zn homeostasis. Cell line-dependent differences in the regulation of Zn homeostasis were detected.

A standardised challenge model with an enterotoxigenic F4+ Escherichia coli strain in piglets assessing clinical traits and faecal shedding of fae and est-II toxin genes.

This study evaluated the effect of five feed additives on post weaning diarrhoea (PWD) in piglets challenged 3 d after weaning with an enterotoxigenic Escherichia coli strain (ETEC). In three experimental runs, a total of 84 piglets was weaned at 21 days of age and randomly assigned to seven treatments. As dietary treatment, piglets were fed a basal diet or diets with addition of bovine colostrum (0.2%), pineapple stem extract containing bromelain (0.2%), an autolysed yeast preparation (Saccharomyces cerevisiae) (0.1%), a combination of organic acids (0.7%) and a phytogenic product with thyme essential oil (0.015%). A porcine ETEC, serotype O149:K91:K88ac was given twice via oral infection on day 3 after weaning at 10(10) colony forming units/animal. One group of piglets was fed the basal diet without ETEC challenge. Traits included clinical sores, body temperature, faecal scoring and determination of faecal dry matter and the shedding of fae and est-II ETEC toxin genes. After weaning, non-challenged control piglets did not show signs of diarrhoea or impaired health, while the majority of infected piglets had a drop in body temperature, signs of diarrhoea and impaired general health. Mortality, the decrease of faecal dry matter and shedding of the toxin genes fae and est-II were not affected by the different additives. In conclusion, the ETEC challenge model induced distinct clinical signs of PWD in piglets, but the tested feed additives had no preventive effect under these conditions.

Effect of dietary zinc oxide on morphological characteristics, mucin composition and gene expression in the colon of weaned piglets.

The trace element zinc is often used in the diet of weaned piglets, as high doses have resulted in positive effects on intestinal health. However, the majority of previous studies evaluated zinc supplementations for a short period only and focused on the small intestine. The hypothesis of the present study was that low, medium and high levels of dietary zinc (57, 164 and 2,425 mg Zn/kg from zinc oxide) would affect colonic morphology and innate host defense mechanisms across 4 weeks post-weaning. Histological examinations were conducted regarding the colonic morphology and neutral, acidic, sialylated and sulphated mucins. The mRNA expression levels of mucin (MUC) 1, 2, 13, 20, toll-like receptor (TLR) 2, 4, interleukin (IL)-1ß, 8, 10, interferon-γ (IFN-γ) and transforming growth factor-ß (TGF-ß) were also measured. The colonic crypt area increased in an age-depending manner, and the greatest area was found with medium concentration of dietary zinc. With the high concentration of dietary zinc, the number of goblet cells containing mixed neutral-acidic mucins and total mucins increased. Sialomucin containing goblet cells increased age-dependently. The expression of MUC2 increased with age and reached the highest level at 47 days of age. The expression levels of TLR2 and 4 decreased with age. The mRNA expression of TLR4 and the pro-inflammatory cytokine IL-8 were down-regulated with high dietary zinc treatment, while piglets fed with medium dietary zinc had the highest expression. It is concluded that dietary zinc level had a clear impact on colonic morphology, mucin profiles and immunological traits in piglets after weaning. Those changes might support local defense mechanisms and affect colonic physiology and contribute to the reported reduction of post-weaning diarrhea.

High-dose dietary zinc oxide mitigates infection with transmissible gastroenteritis virus in piglets.

BACKGROUND: Zinc (Zn) supplementation has been shown to reduce the incidence of diarrhea and to protect animals from intestinal diseases, but the mechanisms of this protective effect against virus infection in vivo have not yet been elucidated. Transmissible gastroenteritis virus (TGEV) causes diarrhea in piglets with an age-dependent decrease of severity. RESULTS: We used 60 weaned piglets that were divided into three groups to evaluate the effect of different Zn levels added to a conventional diet (50 mg Zn/kg diet, Znlow, control group). The other groups received the diet supplemented with ZnO at final concentrations of 150 mg Zn/kg diet (Znmed), or 2,500 mg/kg diet (Znhigh). Oral challenge infection with TGEV was performed when the pigs had been fed for 1 week with the respective diet. Half of the piglets of each group were sacrificed at day 1 and 18 after challenge infection. Fecal consistency was improved and body weights increased in the Znhigh group when compared to the other groups, but no direct effect of Zn concentrations in the diet on fecal TGEV shedding and mucosal immune responses was detectable. However, in the Znhigh group, we found a prevention of villus atrophy and decreased caspase-3-mediated apoptosis of jejunal epithelium. Furthermore, pigs receiving high Zn diet showed a down-regulation of interferon (IFN)-α, oligoadenylate synthetase (OAS), Zn transporter SLC39A4 (ZIP4), but up-regulation of metallothionein-1 (MT1), as well as the Zn transporters SLC30A1 (ZnT1) and SLC30A5 (ZnT5). In addition, forskolin-induced chloride secretion and epithelial resistance were controlled at a physiological level in the Znhigh but not the other groups. Finally, in the Znhigh group, we documented an earlier and higher systemic TGEV-specific serum antibody response. CONCLUSIONS: These results suggest that high dietary Zn could provide enhanced protection in the intestinal tract and stimulate the systemic humoral immune response against TGEV infection.

Dietary Enterococcus faecium NCIMB 10415 and zinc oxide stimulate immune reactions to trivalent influenza vaccination in pigs but do not affect virological response upon challenge infection.

Swine influenza viruses (SIV) regularly cause significant disease in pigs worldwide. Since there is no causative treatment of SIV, we tested if probiotic Enterococcus (E.) faecium NCIMB 10415 or zinc (Zn) oxide as feed supplements provide beneficial effects upon SIV infection in piglets. Seventy-two weaned piglets were fed three different diets containing either E. faecium or different levels of Zn (2500 ppm, Zn(high); 50 ppm, Zn(low)). Half of the piglets were vaccinated intramuscularly (VAC) twice with an inactivated trivalent SIV vaccine, while all piglets were then infected intranasally with H3N2 SIV. Significantly higher weekly weight gains were observed in the E. faecium group before virus infection, and piglets in Zn(high) and E. faecium groups gained weight after infection while those in the control group (Zn(low)) lost weight. Using ELISA, we found significantly higher H3N2-specific antibody levels in the E. faecium+VAC group 2 days before and at the day of challenge infection as well as at 4 and 6 days after challenge infection. Higher hemagglutination inhibition (HI) titers were also observed in the Zn(high)+VAC and E. faecium+VAC groups at 0, 1 and 4 days after infection. However, there were no significant differences in virus shedding and lung lesions between the dietary groups. Using flow cytometry analysis significantly higher activated T helper cells and cytotoxic T lymphocyte percentages in the PBMCs were detected in the Zn(high) and E. faecium groups at single time points after infection compared to the Zn(low) control group, but no prolonged effect was found. In the BAL cells no influence of dietary supplementation on immune cell percentages could be detected. Our results suggest that feeding high doses of zinc oxide and particularly E. faecium could beneficially influence humoral immune responses after vaccination and recovery from SIV infection, but not affect virus shedding and lung pathology.

Feeding low or pharmacological concentrations of zinc oxide changes the hepatic proteome profiles in weaned piglets.

Pharmacological levels of zinc oxide can promote growth and health of weaning piglets, but the underlying molecular mechanisms are yet not fully understood. The aim of this study was to determine changes in the global hepatic protein expression in response to dietary zinc oxide in weaned piglets. Nine half-sib piglets were allocated to three dietary zinc treatment groups (50, 150, 2500 mg/kg dry matter). After 14 d, pigs were euthanized and liver samples taken. The increase in hepatic zinc concentration following dietary supplementation of zinc was accompanied by up-regulation of metallothionein mRNA and protein expression. Global hepatic protein profiles were obtained by two-dimensional difference gel electrophoresis following matrix-assisted laser desorption ionization/time-of-flight mass spectrometry. A total of 15 proteins were differentially (P<0.05) expressed between groups receiving control (150 mg/kg) or pharmacological levels of zinc (2500 mg/kg) with 7 down- (e.g. arginase1, thiosulfate sulfurtransferase, HSP70) and 8 up-regulated (e.g. apolipoprotein AI, transferrin, C1-tetrahydrofolate synthase) proteins. Additionally, three proteins were differentially expressed with low zinc supply (50 mg/kg Zn) in comparison to the control diet. The identified proteins were mainly associated with functions related to cellular stress, transport, metabolism, and signal transduction. The differential regulation was evaluated at the mRNA level and a subset of three proteins of different functional groups was selected for confirmation by western blotting. The results of this proteomic study suggest that zinc affects important liver functions such as blood protein secretion, protein metabolism, detoxification and redox homeostasis, thus supporting the hypothesis of intermediary effects of pharmacological levels of zinc oxide fed to pigs.

The broader context of antibiotic resistance: zinc feed supplementation of piglets increases the proportion of multi-resistant Escherichia coli in vivo.

Following the Europe-wide ban of antimicrobial growth promoters, feed supplementation with zinc has increased in livestock breeding. In addition to possible beneficial effects on animal health, feed supplementation with heavy metals is known to influence the gut microbiota and might promote the spread of antimicrobial resistance via co-selection or other mechanisms. As Escherichia coli is among the most important pathogens in pig production and often displays multi-resistant phenotypes, we set out to investigate the influence of zinc feed additives on the composition of the E. coli populations in vivo focusing on phylogenetic diversity and antimicrobial resistance. In a piglet feeding trial, E. coli were isolated from ileum and colon digesta of high dose zinc-supplemented (2500ppm) and background dose (50ppm) piglets (control group). The E. coli population was characterized via pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST) for the determination of the phylogenetic background. Phenotypic resistance screening via agar disk diffusion and minimum inhibitory concentration testing was followed by detection of resistance genes for selected clones. We observed a higher diversity of E. coli clones in animals supplemented with zinc compared to the background control group. The proportion of multi-resistant E. coli was significantly increased in the zinc group compared to the control group (18.6% vs. 0%). For several subclones present both in the feeding and the control group we detected up to three additional phenotypic and genotypic resistances in the subclones from the zinc feeding group. Characterization of these subclones suggests an increase in antimicrobial resistance due to influences on plasmid uptake by zinc supplementation, questioning the reasonability of zinc feed additives as a result of the ban of antimicrobial growth promoters.

Feeding of the probiotic bacterium Enterococcus faecium NCIMB 10415 differentially affects shedding of enteric viruses in pigs.

Effects of probiotic bacteria on viral infections have been described previously. Here, two groups of sows and their piglets were fed with or without feed supplementation of the probiotic bacterium Enterococcus faecium NCIMB 10415. Shedding of enteric viruses naturally occurring in these pigs was analyzed by quantitative real-time RT-PCR. No differences between the groups were recorded for hepatitis E virus, encephalomyocarditis virus and norovirus. In contrast, astrovirus was exclusively detected in the non-supplemented control group. Rotavirus was shedded later and with lower amounts in the probiotic piglet group (p < 0.05); rotavirus-shedding piglets gained less weight than non-infected animals (p < 0.05). Serum titres of anti-rotavirus IgA and IgG antibodies were higher in piglets from the control group, whereas no difference was detected between sow groups. Phenotype analysis of immune cell antigens revealed significant differences of the CD4 and CD8ß (p < 0.05) as well as CD8α and CD25 (p < 0.1) T cell populations of the probiotic supplemented group compared to the non-supplemented control group. In addition, differences were evident for CD21/MHCII-positive (p < 0.05) and IgM-positive (p < 0.1) B cell populations. The results indicate that probiotic bacteria could have effects on virus shedding in naturally infected pigs, which depend on the virus type. These effects seem to be caused by immunological changes; however, the distinct mechanism of action remains to be elucidated.

Effect of barley and oat cultivars with different carbohydrate compositions on the intestinal bacterial communities in weaned piglets.

This experiment was aimed at comparing the intestinal microbial community composition in pigs fed hulled common barley supplemented with isolated barley mixed-linked beta-glucan, four hulless barley varieties and breeding lines with mixed-linked beta-glucan contents ranging from 41 to 84 g kg(-1) and different amylose/amylopectin ratios as well as two oat varieties. Seventy-two weaned piglets were allocated to one of nine diets composed of 81.5% cereal, 6% whey, 9% soy protein isolate and 3.5% minerals. After 15 days, pigs were sacrificed and ileum and colon contents were collected for quantitative real-time PCR (qPCR) and denaturing gradient gel electrophoresis to evaluate microbial communities. Shifts in intestinal microbial communities were observed with the hulless barley cultivars with a normal to high beta-glucan content and from normal starch toward either high-amylopectin or high-amylose starch. These hulless barleys had the lowest (P<0.05) microbial diversity, whereas oats had intermediate diversity compared with low-beta-glucan hulless cultivars and hulled varieties. Furthermore, hulless varieties favoured xylan- and beta-glucan-degrading bacteria whereas mixed-linked beta-glucan-supplemented hulled barley favoured lactobacilli. Numbers of lactobacilli decreased in the ileum of pigs fed hulless/high mixed-linked beta-glucan barley-based diets. Thus, cultivar differences in both the form and the quantity of carbohydrates affect gut microbiota in pigs, which provides information for future feeding strategies.