The Zinc Concentration in the Diet and the Length of the Feeding Period Affect the Methylation Status of the ZIP4 Zinc Transporter Gene in Piglets

Zinc status and indicators of intestinal health in enterotoxigenic Escherichia coli F18 challenged newly weaned pigs fed diets with different levels of zinc

This study investigated the impact of an enterotoxigenic Escherichia coli (ETEC) F18 challenge on newly weaned pigs when fed one of three Zn levels (150, 1,400, or 2,500 ppm) on performance, Zn status, ETEC shedding, and diarrhea. The ETEC challenge was hypothesized to have a more pronounced negative impact on pigs fed a diet containing 150 ppm Zn compared to 1,400 or 2,500 ppm Zn for 14 d after weaning. The study included 72 ETEC F18 susceptible pigs weaned at ~28 d of age (d 0 of the study). The pigs were distributed according to initial weight and litter to one of the three dietary Zn levels. Half of the pigs were challenged with ETEC on d 1 and 2. The challenge reduced (P ≤ 0.03) feed intake and average daily gain (ADG) during d 3 to 5. Challenged pigs fed 150 ppm Zn had lower (P = 0.01) ADG during d 5 to 7 compared to those fed 1,400 or 2,500 ppm Zn, whereas control pigs' ADG were not affected by dietary Zn content. Challenged pigs fed 150 ppm Zn also showed lower (P < 0.01) fecal dry matter (DM) on d 5 compared to control pigs fed 150 ppm Zn and challenged pigs fed 1,400 or 2,500 ppm Zn. Challenge increased (P < 0.01) ETEC shedding in all groups, but challenged pigs fed 150 ppm Zn showed higher (P ≤ 0.05) fecal shedding of ETEC and toxins than when fed 1,400 or 2,500 ppm. On d 3, C-reactive protein concentration in plasma was lower (P < 0.03) for pigs fed 1,400 and 2,500 compared to 150 ppm Zn. Plasma haptoglobin and pig major acute phase protein were unaffected by dietary Zn content. On d 0, the serum Zn concentration was 586 ± 36.6 µg/L, which pigs fed 150 ppm Zn maintained throughout the study. The serum Zn concentration increased (P ≤ 0.07) in pigs fed 1,400 or 2,500 ppm Zn. The challenge decreased (P < 0.01) the serum Zn concentration in pigs fed 2,500 ppm Zn. On d 5 and 7, serum Zn concentration was similar for challenged pigs fed 1,400 and 2,500 ppm Zn, while control pigs fed 2,500 ppm Zn had higher (P < 0.01) serum Zn concentration than 1,400 ppm Zn. On d 7, serum Zn concentration tended (P = 0.08) to be lower for pigs with diarrhea (fecal DM ≤ 18%). In summary, these results indicate that newly weaned pigs fed 150 ppm Zn are more susceptible to ETEC F18 colonization and its adverse consequences such as diarrhea and reduced growth, even though challenge did not increase acute phase proteins.

Comparison of antimicrobial resistant Escherichia coli isolated from Irish commercial pig farms with and without zinc oxide and antimicrobial usage

BACKGROUND

The prophylactic use of antimicrobials and zinc oxide (ZnO) in pig production was prohibited by the European Union in 2022 due to potential associations between antimicrobial and heavy metal usage with antimicrobial resistance (AMR) and concerns regarding environmental pollution. However, the effects of their usage on the bacterial AMR profiles on commercial pig farms are still not fully understood and previous studies examining the effect of ZnO have reported contrasting findings. The objective of this study was to examine the effects of antimicrobial and ZnO usage on AMR on commercial pig farms. Faecal and environmental samples were taken on 10 Irish commercial farms, of which 5 farms regularly used ZnO and antimicrobials (amoxicillin or sulphadiazine-trimethoprim) for the prevention of disease. The other 5 farms did not use ZnO or any other form of prophylaxis. Escherichia coli numbers were quantified from all samples using non-supplemented and supplemented Tryptone Bile X-glucuronide agar.

RESULTS

In total 351 isolates were phenotypically analysed, and the genomes of 44 AmpC/ESBL-producing E. coli isolates from 4 farms were characterised using whole-genome sequencing. Phenotypic analysis suggested higher numbers of multi-drug resistant (MDR) E. coli isolates on farms using prophylaxis. Furthermore, farms using prophylaxis were associated with higher numbers of isolates resistant to apramycin, trimethoprim, tetracycline, streptomycin, and chloramphenicol, while resistance to ciprofloxacin was more associated with farms not using any prophylaxis. Thirty-four of the 44 AmpC/ESBL-producing E. coli strains harboured the bla_CTX-M-1 resistance gene and were multi drug resistant (MDR). Moreover, network analysis of plasmids and analysis of integrons showed that antimicrobial and biocide resistance genes were frequently co-located on mobile genetic elements, indicating the possibility for co-selection during antimicrobial or biocide usage as a contributor to AMR occurrence and persistence on farms.

CONCLUSIONS

The results of this study showed evidence that antimicrobial and ZnO treatment of pigs post-weaning can favour the selection and development of AMR and MDR E. coli. Co-location of resistance genes on mobile genetic elements was observed. This study demonstrated the usefulness of phenotypic and genotypic detection of antimicrobial resistance by combining sequencing and microbiological methods.

Role of Zinc (Zn) in Human Reproduction: A Journey from Initial Spermatogenesis to Childbirth

Zinc (Zn), the second-most necessary trace element, is abundant in the human body. The human body lacks the capacity to store Zn; hence, the dietary intake of Zn is essential for various functions and metabolism. The uptake of Zn during its transport through the body is important for proper development of the three major accessory sex glands: the testis, epididymis, and prostate. It plays key roles in the initial stages of germ cell development and spermatogenesis, sperm cell development and maturation, ejaculation, liquefaction, the binding of spermatozoa and prostasomes, capacitation, and fertilization. The prostate releases more Zn into the seminal plasma during ejaculation, and it plays a significant role in sperm release and motility. During the maternal, labor, perinatal, and neonatal periods, the part of Zn is vital. The average dietary intake of Zn is in the range of 8-12 mg/day in developing countries during the maternal period. Globally, the dietary intake of Zn varies for pregnant and lactating mothers, but the average Zn intake is in the range of 9.6-11.2 mg/day. The absence of Zn and the consequences of this have been discussed using critical evidence. The events and functions of Zn related to successful fertilization have been summarized in detail. Briefly, our current review emphasizes the role of Zn at each stage of human reproduction, from the spermatogenesis process to childbirth. The role of Zn and its supplementation in in vitro fertilization (IVF) opens opportunities for future studies on reproductive biology.

Zinc Supplementation Forms Influenced Zinc Absorption and Accumulation in Piglets

The study aimed at determining the effect of different zinc (Zn) supplementation forms on Zn accumulation, activities of Zn-containing enzymes, gene expression of metallothionein (MT), and Zn transporters in piglets. Eighteen piglets were randomly divided into three groups: (a) a basal diet supplemented with 150 mg/kg Zn from Zn methionine (Zn-Met) in the feed (Zn-Met group), (b) a basal diet supplemented with 150 mg/kg Zn from Zn sulfate (ZnSO₄) in the feed (ZnSO₄, _feed group), and (c) a basal diet supplemented with the same dose of Zn as in ZnSO4,_feed group but in water (ZnSO₄, _water group). The results showed that Zn-Met added in feed and ZnSO₄ dissolved in drinking water significantly improved (p < 0.05) the Zn concentration in liver and jejunum and the apparent digestibility of Zn in comparison with the ZnSO₄ added in feed. In addition, dietary Zn supplementation as Zn-Met significantly increased (p < 0.05) the activity of alkaline phosphatase (AKP) in the jejunum of piglets in comparison with the ZnSO₄, _feed group. Furthermore, the Zn-Met and ZnSO₄, _water groups showed an improved total superoxide dismutase activity (T-SOD) in the ileum as compared to the ZnSO₄, _feed group. Meanwhile, the qPCR and western blot results showed that Zn-Met and ZnSO₄ dissolved in drinking water increased the expression of MT in the jejunum in comparison with the ZnSO₄ added in the piglets' feed. However, different Zn supplementation forms had no effect on the mRNA expressions of Zip4 and ZnT1 transporters. In conclusion, Zn-Met added in feed and ZnSO₄ dissolved in drinking water had higher bioavailability in piglets.

Zinc deficiency impairs interferon-γ production on post-transcriptional level

BACKGROUND

Zinc is a trace element and is thus commonly known to be indispensable for regular cellular function. Until today, zinc deficiency is a widespread health problem, affecting approximately one sixth of the world's population. Especially the immune system has proven to be highly dependent on zinc. Interferon-γ (IFN-γ) is a key element in the defense against intracellular pathogens. A lack of this cytokine results in immunological impairment, whereas an excess can lead to autoimmunity, highlighting the importance of a well-regulated IFN-γ expression. In a state of zinc deficiency, the production of this cytokine has long been shown to be reduced. Providing further insight into the molecular mechanisms responsible for this interaction is the primary objective of this study.

METHODS

Zinc-deficient or -supplemented cell culture, ELISA, quantitative PCR, methylation analysis.

RESULTS

Promoter methylation is a typical mechanism of gene silencing and a strong regulating factor for IFN-γ production. An analysis of the methylation status of IFN-γ and its transcription factor IRF4 in human PBMC in a state of cellular zinc deficiency or excess showed no dependency on the trace metal. Unexpectedly, zinc-deficient PBMC, which secreted significantly less IFN-γ protein, showed significantly higher mRNA levels of the cytokine compared to cells with high total zinc levels.

CONCLUSION

This report is the first about this unconventional ratio of IFN-γ mRNA to protein. Such a mismatch is highly relevant to the study of protein production in general and that of IFN-γ in particular. Based on our results and the latest research, we hypothesize a strong post-transcriptional effect of zinc on IFN-γ.

Zinc abrogates anticancer drug tamoxifen-induced hepatotoxicity by suppressing redox imbalance, NO/iNOS/NF-ĸB signaling, and caspase-3-dependent apoptosis in female rats

Tamoxifen (TAM) is used in breast cancer chemotherapy since its approval by the Food and Drug Administration in 1977. However, TAM therapy is accompanied with hepatotoxicity - a source of worry to clinicians. Oxidative stress and inflammation are the major implicated mechanisms contributing to TAM hepatotoxicity. In this study, we explored whether zinc (Zn) supplementation could prevent TAM-induced hepatotoxicity in female Wistar rats. Rats were subjected to oral pretreatment of Zn (100 mg/kg body weight (b.w.)/day) for 14 days against hepatic toxicity induced by single intraperitoneal administration of TAM (50 mg/kg b.w.) on day 13. TAM markedly elevated serum liver enzymes, whereas total protein and albumin considerably reduced. TAM caused prominent depletion of hepatic-reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activity. Also, TAM significantly increased malondialdehyde (MDA) level. Further, it raised liver levels of tumor necrosis factor-α (TNF-α), interleukin-1β, (IL-1β), interleukin-6 (IL-6), and nitric oxide (NO) confirmed by the liver histopathological alterations. The mechanistic inflammatory expression of inducible nitric oxide synthase (iNOS) and nuclear factor-kappa B (NF-ĸB), and expression of caspase-3 protein prominently increased. Zinc supplementation significantly modulated serum liver function markers, antioxidant enzymes, and GSH and MDA levels. Zinc downregulated the expression of cytokines, NO, iNOS, NF-ĸB and caspase-3, and ameliorated histopathological changes. Zinc protects against TAM-induced hepatotoxicity; it may serve as an adjuvant supplement for female patients undergoing TAM chemotherapy.

Long-Term Effects of Zinc Deficiency and Zinc Supplementation on Developmental Seizure-Induced Brain Damage and the Underlying GPR39/ZnT-3 and MBP Expression in the Hippocampus

We previously illustrated that long-term upregulated expression of ZnT-3 in the hippocampus of rats that underwent neonatal seizures was restored by pretreatment with a ketogenic diet. It was recently demonstrated that upregulated expression of ZnT-3 was associated with increased concentrations of intracellular free zinc ions in an in vitro model of glutamate-induced hippocampal neuronal excitotoxic damage. However, there is still a lack of research on the effects of different concentrations of zinc in the diet on developmental convulsive brain injury. The aim of this study was to investigate the effects of different zinc concentrations in the diet on long-term neurobehavioral and seizure thresholds following lithium chloride-pilocarpine-induced developmental seizures. Sprague-Dawley rats (postnatal day 27, P27) were randomly assigned to one of six dietary groups for 4 weeks: normal zinc control group (Control group, 44 mg/kg Zn), Zn-deficient control group (ZD group, 2.7 mg/kg Zn), Zn supplemented control group (ZS group, 246 mg/kg Zn), pilocarpine-induced seizure plus regular zinc diet group (SE group, 44 mg/kg Zn), seizure plus low-zinc diet group (SE + ZD group, 2.7 mg/kg Zn), and seizure plus high-zinc diet group (SE + ZS group, 246 mg/kg Zn). Novel object recognition and passive avoidance tests were performed on rats at P42 and P56. After routine seizure threshold detection and Timm staining procedures at P57, expression of GPR39, ZnT-3, and MBP were detected in the hippocampus by Western blot analysis. The results revealed that the Zinc-deficient diet for 4 weeks aggravated the long-term adverse effects of developmental seizures, evidenced by weight, cognition, seizure threshold and serum zinc concentrations, which were paralleled by expression changes in hippocampal GPR39 and ZnT-3. In contrast, zinc supplementation for 4 weeks significantly improved damage-related changes described above and rescued the abnormal expression of GPR39, ZnT-3, and MBP in the hippocampus. Similar alterations between the expression pattern of MBP and aberrant sprouting of mossy fibers in the hippocampus may indicate that sprouting is a secondary pathological change caused by developmental brain damage rather than the cause of epileptogenesis. Up-regulation of MBP protein levels in the high zinc diet-treated seizure group as well as the corresponding improvement of cognitive impairment and reduced hippocampal mossy fiber regenerative sprouting, may represent a compensatory mechanism for neuronal membrane damage and repair.

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 CD8β + 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.

Diet-dependent changes in the intestinal DNA methylome after introduction of enteral feeding in preterm pigs

AIM

To examine how enteral feeding affects the intestinal epigenome and gene expression just after preterm birth.

MATERIALS & METHODS

Intestinal tissue from preterm pigs, modeling preterm infants, was collected at birth and 5 days after gradual introduction of infant formula or bovine colostrum. The intestinal tissue was analyzed by reduced representation bisulfite sequencing and real-time qPCR.

RESULTS

Relative to colostrum, formula increased bacterial epithelial adherence and lipopolysaccharide binding protein (LBP) expression, which was regulated by promoter methylation. Diet-dependent changes in DNA methylation and/or mRNA expression were related to innate immune response, hypoxia, angiogenesis and epithelial-mesenchymal transition pathways (e.g., TTC38, IL8, C3, HIF1A and VEGFR1).

CONCLUSION

Epigenetic changes may mediate important effects of the first feeding on intestinal development in preterm neonates.

High dietary zinc feeding promotes persistence of multi-resistant E. coli in the swine gut

High levels of zinc oxide are used frequently as feed additive in pigs to improve gut health and growth performance and are still suggested as an alternative to antimicrobial growth promoters. However, we have recently described an increase of multi-resistant E. coli in association to zinc feeding in piglets. This previous study focused on clonal diversity of E. coli, observing the effect on multi-resistant strains by chance. To shed further light into this highly important topic and falsify our previous findings, we performed a zinc pig feeding trial where we specifically focused on in-depth analysis of antimicrobial resistant E. coli. Under controlled experimental conditions, piglets were randomly allocated to a high dietary zinc (zinc group) and a background zinc feeding group (control group). At different ages samples were taken from feces, digesta, and mucosa and absolute E. coli numbers were determined. A total of 2665 E. coli isolates were than phenotypically tested for antimicrobial resistance and results were confirmed by minimum inhibitory concentration testing for random samples. In piglets fed with high dietary zinc, we detected a substantial increase of multi-resistant E. coli in all gut habitats tested, ranging from 28.9–30.2% multi-resistant E. coli compared to 5.8–14.0% in the control group. This increase was independent of the total number of E. coli. Interestingly, the total amount of the E. coli population decreased over time. Thus, the increase of the multi-resistant E. coli populations seems to be linked with persistence of the resistant population, caused by the influence of high dietary zinc feeding. In conclusion, these findings corroborate our previous report linking high dietary zinc feeding of piglets with the occurrence of antimicrobial resistant E. coli and therefore question the feeding of high dietary zinc oxide as alternative to antimicrobial growth promoters.

Nutritional Influence on Epigenetic Marks and Effect on Livestock Production

Nutrition represents one of the greatest environmental determinants of an individual’s health. While nutrient quantity and quality impart direct effects, the interaction of nutrition with genetic and epigenetic modifications is often overlooked despite being shown to influence biological variation in mammals. Dissecting complex traits, such as those that are diet or nutrition related, to determine the genetic and epigenetic contributions toward a phenotype can be a formidable process. Epigenetic modifications add another layer of complexity as they do not change the DNA sequence itself but can affect transcription and are important mediators of gene expression and ensuing phenotypic variation. Altered carbohydrate metabolism and rates of fat and protein deposition resulting from diet-induced hypo- or hyper-methylation highlight the capability of nutritional epigenetics to influence livestock commodity quality and quantity. This interaction can yield either products tailored to consumer preference, such as marbling in meat cuts, or potentially increasing productivity and yield both in terms of carcass yield and/or offspring performance. Understanding how these and other desirable phenotypes result from epigenetic mechanisms will facilitate their inducible potential in livestock systems. Here, we discuss the establishment of the epigenome, examples of nutritional mediated alterations of epigenetics and epigenetic effects on livestock production.