Zinc Excretion Research Articles

PSIV-19 The use of microencapsulated zinc oxide improves the growth performance and intestinal health of newly weaned piglets

Abstract The application of microencapsulation technology to protect zinc may support inclusion of reduced levels with similar benefits to elevated doses of free zinc oxide. This study aimed to compare the effects of different doses of a microencapsulated ZnO (Zinco-Plus S) and free ZnO in nursery diets on growth performance and intestinal health of pigs. A total of 480 newly weaned piglets [26 d of age, initial body weight (BW) = 7.39 kg] were randomly assigned to one of four dietary treatments for 35d. Treatments were as follow: free ZnO (3,000, 1,500, and 0 ppm at phase 1, 2, and 3, respectively) or one of three doses of the microencapsulated ZnO (400, 600, and 800 ppm) maintained consistently across all 3 nursery phases (total amount of zinc in diets were within limits allowed by Canadian regulation). Each dietary treatment had 10 replicates, with 12 pigs/pen, gender balanced. All treatments had protease (Jefo Protease; 125 g/t), xylanase (Belfeed Xylanase; 100 g/t) and protected organic acids and essential oils (Porcinat+; 2 kg/t in phase 1 and 2, 1 kg/t in phase 3). Body weight, BW gain and feed intake were measured to determine feed conversion. At the end of phase 1, fecal sample was collected (pooled of 4 samples/pen) to determine zinc excretion. At the end of phase 2, blood serum was collected (1 pig/pen) to measure calprotectin and diamine oxidase concentrations and, ileal tissue was collected (1 pig/pen) to measure expression of zonular occludens (ZO) -1. Data were submitted to ANOVA and Fisher test with significance set at P < 0.05. There was no difference (P > 0.05) in final BW of pigs across all treatments. Nonetheless, piglets receiving 800 ppm of the microencapsulated ZnO had improved (P < 0.05) feed conversion ratio compared with pigs fed diet containing free ZnO. There was no difference (P > 0.05) in serum concentrations of calprotectin and diamine oxidase across all treatments, indicating improved intestinal health regardless of the form of ZnO. Piglets supplemented with microencapsulated ZnO at 800 ppm had an increased (P < 0.05) intestinal expression of ZO-1 in comparison with piglets receiving free ZnO, indicating better intestinal integrity. Fecal zinc concentrations were reduced (P < 0.05) by 75 % with the inclusion of microencapsulated ZnO compared with free ZnO. Piglets supplemented with microencapsulated ZnO at 800 ppm improved (P < 0.05) feed cost per kg BW gain by 10.7 % when compared with free ZnO. These findings show that supplementing lower levels of zinc in nursery diets via microencapsulation technology improves growth performance and supports intestinal health at levels comparable with increased free ZnO supplementation. Moreover, the utilization of microencapsulated zinc oxide has the additional advantage of minimizing environmental impact through the reduction of zinc wastage.

Association of serum zinc with mineral stress in chronic kidney disease.

The excessive cardiovascular mortality of patients with chronic kidney disease (CKD) could be linked to mineral stress, the biological consequence of calcium-phosphate nanoparticle exposure. This study investigated whether zinc is associated with mineral stress markers in CKD. Zinc and T50 (serum calcification propensity) as well as hydrodynamic radius of secondary calciprotein particles (CPP2) were measured in blood donors and CKD patients with/out dialysis. Serum zinc concentrations and T50 were reduced, while CPP2 radius was increased in CKD patients. Serum zinc levels positively correlated with T50 and inversely correlated with CPP2 radius. In a hierarchical linear regression model, T50 was associated with age, calcium, phosphate, magnesium and albumin. Addition of zinc significantly improved prediction of the model, confirming an additional contribution of zinc to T50. Similar observations were made for the association of zinc and CPP2 radius, but spiking experiments indicated that zinc may stronger modify T50 than CPP2 radius. Also, urinary zinc excretion was increased in patients with kidney disease and correlated to T50 and CPP2 radius. Serum zinc further correlated with markers of arterial stiffness in blood donors and CKD patients, but these associations did not remain significant in a multivariate linear regression model. Reduced serum zinc levels in CKD appear directly linked to lower T50 and associated with larger CPP2 radius. Further studies on the associations of zinc and mineral stress as well as putative therapeutic benefits of zinc supplementation are required.

Methods of Assessment of Zinc Status in Humans: An Updated Review and Meta-analysis.

The assessment of zinc status is difficult but essential for the identification of zinc deficiency and evaluation of interventions to improve zinc status. The purpose of this systematic review (SR) and meta-analysis was to update the previously published SR of biomarkers of zinc status, conducted by the European Micronutrient Recommendations Aligned (EURRECA) network in 2009, to answer the question: Which putative measures (biomarkers) of zinc status appropriately reflect a change in zinc intake of at least 2 weeks? A structured search strategy was used to identify articles published between January 2007 and September 2022 from MEDLINE (Ovid), Embase (Ovid), Cochrane Database of Systematic Reviews, and Cochrane Central Register of Controlled Trials (CENTRAL). Relevant articles were identified using previously defined eligibility criteria. Data were extracted and combined with data from the previous SR. A random-effects model was used to calculate pooled mean differences using STATA (StataCorp). The risk of bias and the certainty of evidence for all outcomes were assessed. Additional data on 7 of the 32 previously reported biomarkers were identified, along with data on an additional 40 putative biomarkers from studies published since 2007. Pooled data analysis confirmed that, in healthy participants, both plasma/serum zinc concentration and urinary zinc excretion responded to changes in zinc intake (plasma/serum: mean effect [95% CI], controlled studies: 2.17 µmol/L [1.73, 2.61]; P < .005, I2 = 97.8; before-and-after studies: 2.87 µmol/L [2.45, 3.30]; P < .005, I2 = 98.1%; urine zinc: 0.39 mmol/mol creatinine [0.17, 0.62]; P < .005, I2 = 81.2; 3.09 µmol/day [0.16, 6.02]; P = .039, I2 = 94.3). The updated analyses support the conclusion that plasma/serum and urinary zinc respond to changes in zinc intake in studies of healthy participants. Several additional putative biomarkers were identified, but more studies are needed to assess the sensitivity and reliability. PROSPERO no. CRD42020219843.

The expression of Catsup in the hindgut is essential for zinc homeostasis in Drosophila melanogaster.

Zinc excretion is crucial for zinc homeostasis. However, the mechanism of zinc excretion has not been well characterized. Zinc homeostasis in Drosophila seems well conserved to mammals. In this study, we screened all members of the zinc transporters ZnT (SLC30) and Zip (SLC39) for their potential roles in Drosophilahindgut, an insect organ that belongs to the excretory system. The results indicated that Catecholamines up (Catsup, CG10449), a ZIP member localized to the Golgi, is responsible for zinc homeostasis in the hindgut of Drosophila hindgut-specific knockdown of Catsup leads to a developmental arrest in the larval stage, which could be rescued well by human ZIP7. Further study suggested that Catsup RNAi in the hindgut reduced zinc levels in the excretory system (containing the Malpighian tubule and hindgut) but exhibited systemic zinc overload. Besides, more calculi were observed in the Malpighian tubules of Catsup RNAi flies. The developmental arrest and calculi in the Malpighian tubules of hindgut-specific Catsup RNAi flies could be rescued by dietary zinc restriction but hypersensitivity to zinc. These results will help us understand the fundamental process of zinc excretion in higher eukaryotes.

Effects of Increasing Dietary Zinc in Low ABC-4 Diets on Nursery Performance, Fecal Dry Matter, Serum Zinc, and Zinc Excretion

Effects of Increasing Dietary Zinc in Low ABC-4 Diets on Nursery Performance, Fecal Dry Matter, Serum Zinc, and Zinc Excretion

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

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

Regulation of Inorganic Zinc Supplementation on Intestinal Absorption, Metabolism, and Muscle Development in Broilers Fed Low-Protein Diets

The issue of nitrogen fertilizer contamination resulting from high-protein diets can be effectively solved by adopting low-protein diets. The objective of this study was to investigate the effects of inorganic zinc supplementation in low-protein diets on 42-day-old broilers across a multitude of parameters. To determine the optimal dose of inorganic zinc in broiler diets with a 1.5% reduction in crude protein, 1-day-old Arbor Acres broilers (n = 270) were randomly assigned to five groups, each containing 54 broilers. Our results revealed that inorganic zinc supplementation at levels of 130 mg/kg elevated growth performance and carcass traits (p &lt; 0.05). It also significantly increased the ratio of intestinal villi heights to crypt depths (p &lt; 0.001), changed intestinal morphology, and significantly increased albumin content in serum (p &lt; 0.05). Furthermore, analysis of mRNA expression showed that 130 mg/kg and 150 mg/kg of inorganic zinc improved the myogenic differentiation involved in muscle development, as well as intestinal tight junction and liver metallothionein capacity (p &lt; 0.001). Additionally, these groups exhibited lower zinc excretion compared with other treatments (p &lt; 0.001). In summary, our findings suggest that inorganic zinc supplementation in low-protein diets holds the potential to support muscle and intestinal development in broilers, presenting a viable nutritional strategy.

Organic or Inorganic Zinc for Laying Hens? A Systematic Review and Meta-analysis of the Effects of Zinc Sources on Laying Performance, Egg Quality, and Zinc Excretion.

The higher availability of zinc (Zn) from organic than inorganic sources is already established, but more assertive and cost-friendly protocols on the total replacement of inorganic with organic Zn sources for laying hens still need to be developed. Because some discrepancy in the effects of this replacement in laying hen diets is noticeable in the literature, the objective of this meta-analysis was to properly quantify the effect size of total replacing inorganic Zn with organic Zn in the diet of laying hens on their laying performance, egg quality, and Zn excretion. A total of 2340 results were retrieved from Pubmed, Scielo, Scopus, WOS, and Science Direct databases. Of these, 18 primary studies met all the eligibility criteria and were included in this meta-analysis. Overall, the replacement of inorganic Zn with organic Zn, regardless of other factors, improved (p < 0.01) egg production by 1.46%, eggshell thickness by 0.01 mm, and eggshell resistance by 0.11 kgf/cm2. Positive results of the same nutritional strategy on egg weight and Zn excretion were only observed at specific conditions, especially when organic Zn was supplemented alone in the feed, not combined with other organic minerals. Therefore, there is evidence in the literature that the total replacement of inorganic Zn with organic Zn improves egg production, eggshell thickness, and eggshell resistance. Factors such as hen age and genetics, organic Zn source, concentration of Zn in the feed, and the strategy of its supplementation have to be more carefully considered in protocols designed to address egg weight and Zn excretion by the hen.

Exploring potential mechanisms for zinc deficiency to impact in autism spectrum disorder: a narrative review.

Autism spectrum disorder (ASD) is a heterogeneous and complex group of life-long neurodevelopmental disorders. How this clinical condition impacts an individual's intellectual, social and emotional capacities, contributing to alterations in the proprioceptive and sensory systems and increasing their selective attitude towards food, is well described in the literature. This complex condition or status exposes individuals with ASD to an increased risk of developing overweight, obesity and non-communicable diseases compared with the neurotypical population. Moreover, individuals with ASD are characterised by higher levels of inflammation, oxidative stress markers and intestinal dysbiosis. All these clinical features may also appear in zinc deficiency (ZD) condition. In fact, zinc is an essential micronutrient for human health, serving as a structural, catalytic and regulatory component in numerous physiological processes. The aim of this narrative review is to explore role of ZD in ASD. Factors affecting zinc absorption, excretion and dietary intake in this vulnerable population are taken into consideration. Starting from this manuscript, the authors encourage future research to investigate the role of ZD in ASD. The perspective is to potentially find another missing piece in the 'ASD clinical puzzle picture' to improve the health status of these individuals.

Determination of serum zinc concentration in normal healthy men &amp; type II diabetes mellitus patients.

Body zinc content is regulated by the homeostatic mechanism, which regulate zinc absorption and excretion depending on its body requirements. The function of cells and tissues enzymes is depend zinc content &amp; over 70 human body enzymes with which zinc is associated. Pervious studies show that some trace elements like magnesium, zinc, manganese &amp; selenium may play important role in action of insulin hormone, including activation of insulin receptor sites. The aim of the study is to determine the serum level of zinc in normal healthy men &amp; diabetes mellitus type II patients. A cross sectional study was done in Tikrit teaching hospital from beginning of January to end of December 2010. The study conducted on 50 type 2 diabetic male patients was participated in the study. While, 30 normal healthy men age matched (aged 55 to 60 years) were included as a control. Serum zinc was measured for control healthy non diabetic subjects &amp; diabetic type 2 patients. There were non significant differences regarding age. However there is significant increase in BMI of diabetic patients as compare with control men. Fasting serum glucose was significantly higher in DM patients as compare with control subjects. Moreover, there is significant reduction in serum zinc in diabetic patients (89.35 ± 19.23 µg/dl) as compare with normal health subjects (135 ± 35.18 µg/dl). In diabetic patients, there is significant negative correlation between fasting blood sugar &amp; serum zinc (r= - 0.37). In present study conclude that there is a significant reduction in serum zinc in diabetic patients. The present study recommend that diabetic type II patients should be encourage to eat diet rich in zinc or take zinc supplement.

Abstract P170: The Association of Urinary Cadmium and Zinc With Lower Extremity Amputations. Evidence From the Strong Heart Study

Background: Cadmium is a cardiotoxic divalent metal that accumulates in the liver and kidney. It resembles the essential metal zinc, replacing it in numerous enzymes and proteins. Zinc plays a major role in insulin function. Glucose dyshomeostasis increases the loss of zinc through the urine. Cadmium has been associated with peripheral artery disease and critical limb ischemia, conditions that lead to limb amputations. Chelation treatment with edetate disodium, an agent that facilitates the excretion of cadmium from the body, was beneficial for individuals with critical limb ischemia and diabetes in several small studies. This study evaluated the association of urinary levels of cadmium and zinc with amputations in a population with a high burden of diabetes from Arizona, Oklahoma, North Dakota and South Dakota. Hypothesis: We hypothesize that urinary cadmium and zinc levels are related to prevalent amputations in the SHS cohort. Methods: We included 2,724 participants from the Strong Heart Study, a population-based cohort study in 12 American Indian communities, recruited in 1989-1991 and followed for amputations through 1998-1999. Trained staff identified amputations of the lower extremity through visual examination at the baseline visit. We censored traumatic amputations. Baseline metal levels in spot urine samples were divided by urinary creatinine to account for urine dilution. Results: Mean age was 56.4 years, 41.5% participants were male, and 42% had diabetes. We identified a total of 35 (1.3%) amputations of the lower extremities during the study period. Median urinary levels were 0.97 μg/g for cadmium and 0.56 mg/g for zinc. Higher levels of urinary cadmium and zinc were positively associated with the presence of amputations. The odds ratios of prevalent amputations for an IQR of cadmium and zinc distribution were 1.54 (1.00, 2.38) and 2.24 (1.48, 3.39), respectively, in models adjusted for sociodemographic, lifestyle (tobacco and alcohol intake), and other factors (BMI, hypertension and diabetes status, HDL and LDL-cholesterol, and estimated glomerular filtration rate). The associations remained after further adjustment for fasting plasma glucose levels. Urinary cadmium and zinc levels were positively correlated (r=0.24, P&lt;0.001). Conclusions: Urinary cadmium and zinc were positively associated with the presence of lower extremity amputations in American Indian adults with a high burden of diabetes. These results support the current evidence of cadmium as a cardiometabolic risk factor, and the potential role of impaired zinc metabolism, reflected as increased urinary zinc excretion, in vascular complications of diabetes.

Serum zinc levels in cancer patients are low and difficult to elevate when complicated by liver cirrhosis: A retrospective study.

In this study, we analyzed blood zinc concentration in patients with various cancer types and the degree of improvement in relation to the underlying disease following treatment with zinc preparations. Serum zinc levels of 530 cancer patients whose blood zinc levels were measured at our hospital from 2016 to 2021 were retrospectively examined in accordance with the primary disease. Changes in zinc levels were analyzed in 155 patients whose zinc levels had been measured on 2 or more occasions in accordance with whether they had received zinc preparations. In addition, the concentration course of zinc before and after zinc formulation administration in 73 patients was examined in accordance with the presence or absence of liver cirrhosis complications. Mean serum zinc levels were below normal in all carcinomas measured, and zinc levels were significantly lower in cirrhosis-hepatocarcinoma cases than in other primary disease cases. Furthermore, serum zinc levels in patients who did not receive zinc preparations decreased significantly over time. In patients who received zinc preparations, the elevated levels of zinc after treatment were significantly lower in patients with cirrhosis than in those without cirrhosis. There was a weak inverse correlation between pre-dose zinc concentration and increased zinc concentration in patients with cirrhosis. In the analysis of covariance, the presence of liver cirrhosis was predominantly correlated with elevated zinc per dose. In summary, serum zinc levels in cancer patients are low and especially low in cancer patients with liver cirrhosis compared with those without cirrhosis after the administration of zinc preparations.

Association between urinary zinc excretion and isoflavone-metabolizing enterotypes among Japanese females: a cross-sectional study.

Zinc absorption and competition among gut bacteria have been reported in animal studies. Thus, gut bacteria may modify zinc availability in humans. Metabolism of intestinal bacteria is known to be necessary for the activation of several phytoconstituents in the body. For example, equol, a typical substance of soybean isoflavone, is produced by intestinal bacteria metabolizing daidzein and the enterotype is one of distinct ones among Japanese population. The difference in the intestinal microflora can modify the bioavailability of zinc. In this study, we examined urinary zinc concentrations in adult female equol producers (EQPs). Urine samples from women participating in health examinations in Miyagi, Okinawa, Kyoto, Kochi, and Hokkaido prefectures were used; from total 17,484 samples, approximately 25 samples were randomly selected for each age group from 30 to 60 years per region (subsample: n = 520), and 520 samples with available urinary zinc concentration (determined by flame atomic absorption analysis) and enterobacterial type were analyzed. EQP was defined as log(equol/daidzein) ≥ -1.42, and urinary concentrations were corrected for creatinine concentration. Urinary zinc concentrations were compared by Student's t-test and multiple regression analyses. The geometric mean urinary zinc concentration (µg/g-Cr) was lower in EQP than in non-EQP (p = 0.0136 by t-test after logarithm transformation). On the other hand, there was no correlation between urinary zinc concentration with daidzein (r = -0.0495, P = 0.436) and equol concentrations (r = -0.0721, P = 0.256). There was a significant negative association between urinary zinc concentration and EQP (β = -0.392, P = 0.0311) after adjusting with other potential confounding variables, such as daidzein intake. The results suggest that gut bacteria that produce equol are involved in the metabolism of zinc. Based on previous studies, the bacteria that affect the metabolism of both substances are thought to be Enterococcus. Future studies are expected to identify specific intestinal bacteria for zinc availability and understand individual differences in the effects of micronutrients.

Effects of a potentiated zinc oxide on growth performance, incidence of diarrhea, mineral excretion, and bone breaking strength of nursery pigs

The objective of the present study was to evaluate the effects of a potentiated (PZnO) and conventional source of zinc oxide (ZnO) on growth performance, bone breaking strength, incidence of diarrhea, and fecal excretion of phosphorus (P), zinc (Zn), and copper (Cu) of nursery pigs. A total of 84 pigs weaned at 21 d of age (6.1 ± 0.9 kg) were allotted based on a completely randomized block design. The nutritional program was divided in four dietary phases with four dietary treatments: [NC negative control: no ZnO and regular P levels (0.440; 0.420; 0.400; 0.380%); PC positive control: inclusion of ZnO (3,000, 3,000, 2,200, 1,000 ppm) and regular P levels (0.440; 0.420; 0.400; 0.380%); ZnO + PZnO: association between ZnO (1,000, 1,000, 500, 0 ppm) and PZnO (500, 500, 500, 500 ppm) and 10% low P levels (0.396; 0.379; 0.360; 0.340%); PZnO: inclusion of the PZnO (500, 500, 250, 250 ppm) and 10% low P levels (0.396; 0.379; 0.360; 0.340%)]. Data were analyzed using the GLM procedure of SAS 9.4. Pigs fed diets supplemented with PZnO increased overall ADFI (P &lt; 0.05) when compared with treatment with ZnO. Pigs fed diets supplemented with PZnO reduced (P &lt; 0.05) Zn excretion when compared to treatment with ZnO. The treatments with PZnO reduced (P &lt; 0.05) P excretion during phase 3 when compared with treatment with ZnO. In conclusion, the use of PZnO supplemented at lower levels than the conventional source of ZnO, can be a potential alternative to reduce the environmental impact of the swine production systems by optimizing the P utilization, reducing Zn excretion, and still maintaining an optimal feed intake.

Toward revising dietary zinc recommendations for children aged 0 to 3 years: a systematic review and meta-analysis of zinc absorption, excretion, and requirements for growth.

The Food and Agriculture Organization of the United Nations and the World Health Organization are updating their dietary zinc recommendations for children aged 0 to 3 years. The aim of this review was to retrieve and synthesize evidence regarding zinc needs for growth as well as zinc losses, absorption, and bioavailability from the diet. MEDLINE, Embase, and Cochrane Library databases were searched electronically from inception to August 2020. Studies assessing the above factors in healthy children aged 0 to 9 years were included, with no limits on study design or language. Ninety-four studies reporting on zinc content in tissue (n = 27); zinc absorption (n = 47); factors affecting zinc bioavailability (n = 30); and endogenous zinc losses via urine, feces, or integument (n = 40) met the inclusion criteria. Four reviewers extracted data and two reviewers checked for accuracy. Studies were synthesized narratively, and meta-analyses of zinc losses and gains as well the subgroups of age, type of feeding, country's income, and molar ratio of phytate to zinc were conducted. Meta-analysis revealed an overall mean (95%CI) urinary and endogenous fecal zinc excretion of 17.48 µg/kg/d (11.80-23.15; I2 = 94%) and 0.07 mg/kg/d (0.06-0.08; I2 = 82%), respectively, with a mean fractional zinc absorption of 26.75% (23.69-29.81; I2 = 99%). Subgrouping by age revealed differences in mean values associated with the transition from milk-based diets to solid food during the first 3 years of life. This review synthesizes data that may be used to formulate zinc requirements in young children. Results should be interpreted with caution because of considerable heterogeneity in the evidence. PROSPERO registration number CRD42020215236.

Effects of Protein-Chelated Zinc Combined with Mannan-Rich Fraction to Replace High-Dose Zinc Oxide on Growth Performance, Nutrient Digestibility, and Intestinal Health in Weaned Piglets.

A total of 168 weaned piglets (average initial body weight of 7.70 ± 0.75 kg) were used in a 4-week feeding trial to investigate the effects of dietary supplementation with protein-chelated zinc (Zn-Pro) alone or combined with a mannan-rich fraction (MRF) to replace high-dose zinc oxide (ZnO) for weaned piglets. The dietary treatments included a basal diet as control (CON), a ZnO diet (basal diet + 1600 mg Zn/kg from ZnO), a Zn-Pro diet (basal diet + 60 mg Zn/kg from Zn-Pro), and a MRF plus Zn-Pro diet (MRP, basal diet + 800 mg/kg MRF + 60 mg Zn/kg from Zn-Pro). The average daily gain of piglets in the MRP group was higher (p ≤ 0.05) than that in CON and Zn-Pro groups during d 15-28 and d 1-28 of experiment. The apparent total tract digestibility of dry matter, organic matter, and crude protein in the MRP group was higher (p ≤ 0.05) than that in the CON group. The serum insulin-like growth factor-1 level in the MRP group was markedly higher (p ≤ 0.05) than that of piglets in the other three treatment groups. Piglets fed the Zn-Pro and ZnO diets had greater (p ≤ 0.05) acetic acid in cecal digesta than those fed the CON diet, while the MRP diet had higher (p ≤ 0.05) cecal propionate concentration than those that were fed the CON diet on d 28 of experiment. Moreover, the villus height of ileum in the MRP group tended to be greater than the CON group (p = 0.09). Compared with the CON and MRP groups, the relative abundance of Lactobacillaceae (p = 0.08) and Lachnospiraceae (p = 0.09) in the Zn-Pro group showed an increasing trend. The relative abundance of Prevotellaceae in the Zn-Pro group was significantly lower (p ≤ 0.05) than that in the MRP group. In conclusion, the combined addition of MRF and Zn-Pro acted as a suitable alternative to ZnO to beneficially support the growth performance and intestinal health of weaned piglets, as well as contribute to a lower diarrhea rate and environmental pollution from fecal zinc excretion.

Urinary Zinc and Incident Type 2 Diabetes: Prospective Evidence From the Strong Heart Study.

Hyperglycemia can increase urinary zinc excretion. We evaluated the association of higher urinary zinc level with new diagnosis of incident type 2 diabetes mellitus (T2DM) in adult populations with a high burden of T2DM from AZ, OK, and ND and SD. We also assessed the cross-sectional association of urinary zinc levels with prevalent prediabetes. We included 1,339 adults free of T2DM at baseline (1989-1991) followed through 1998-1999 in the Strong Heart Study (SHS) and 1,905 family members of SHS participants followed as part of the Strong Heart Family Study (SHFS) through 2006-2009. T2DM incidence was 14.7% (mean follow-up 6.6 years) in the SHS and 13.5% (mean follow-up 5.6 years) in the SHFS. After adjustment for sex, site, education, smoking status, BMI, and estimated glomerular filtration rate, the hazard ratio of T2DM in comparing 75th vs. 25th percentiles of urinary zinc distribution was 1.21 (95% CI 1.08, 1.36) in the SHS and 1.12 (0.96, 1.31) in the SHFS. These associations were attenuated but significant in the SHS after adjustment for HOMA of insulin resistance (HOMA-IR) score. With exclusion of participants with prediabetes at baseline, urinary zinc remained significantly associated with T2DM in the SHS. In cross-sectional analyses, prediabetes was associated with higher urinary zinc levels. Urinary zinc levels were associated with T2DM incidence and prediabetes prevalence even after adjustment for HOMA-IR in populations with a high burden of T2DM. These results highlight the importance of zinc metabolism in diabetes development.

The potential of spot urine as a biomarker for zinc assessment in Malawian children and adults.

Population-level assessment of zinc deficiency remains a challenge due to the lack of suitable biomarkers. Spot urinary zinc concentration (UZC) has the potential to provide information on population zinc status in large-scale surveys, but there is no established cut-off point indicating deficiency. A strong correlation between this biomarker and an established biomarker such as serum zinc concentration (SZC) in paired samples (i.e., from the same individual), could identify the thresholds indicating zinc deficiency. This study, therefore, aimed to regress spot UZC from school-aged children and women from the Malawi micronutrient survey with paired SZC data using a linear mixed-effects model. The nested variance components indicated no linear relationship between the UZC and SZC data, irrespective of adjustments for inflammation and hydration. Thresholds of urinary zinc excretion that have been suggested by expert panels were applied to the spot UZC data, as a post-hoc analysis. The zinc deficiency prevalence estimates derived from these suggested thresholds were not similar to the estimates from the SZC data, and further research is required to understand whether spot UZC can still provide useful information in population zinc assessment.

Zinc Kinetics Correlate With Length-for-Age z Scores in Bangladeshi Infants.

Stunting [length-for-age z score (LAZ) &lt;-2] has multiple causes and is prevalent in areas with low dietary zinc (Zn) intake. Zinc kinetics from non-stunted infants were used in a published model for predicting linear growth; here, we directly measure zinc kinetics in stunted infants. Zinc kinetics were determined in 9-month-old Bangladeshi infants (n = 10), who were non-wasted [weight-for-length z score (WLZ) &gt; -2], ranging in LAZ from -2.9 to -0.43. Stable isotopes were administered 2 hours after a meal as oral ( 70 Zn) and intravenous ( 67 Zn) tracers. After isotope administration, blood was sampled within 5 hours and all urine and feces were collected for 24 hours. Urine was sampled twice-daily out to 9 days. Data were analyzed by compartmental modeling. Daily zinc intake was estimated by the model as the sum of zinc used for growth plus that lost via urine and feces. Zinc absorbed (the amount required to maintain steady state) was the sum of zinc used for growth plus urine and endogenous fecal excretions. The LAZ score correlated with serum zinc concentration ( R = 0.77, P = 0.001), urinary zinc excretion ( R = 0.66, P = 0.010), and fractional zinc absorption from calculated daily intake ( R = 0.58, P = 0.030). In stunted infants (n = 8), the amount of zinc absorbed did not increase with calculated zinc intake unlike published values for non-stunted infants. Zinc kinetics in Bangladeshi infants correlate with LAZ and show that malabsorption of supplemental sources of zinc may occur in stunted infants.

The Impact of Zinc and Zinc Homeostasis on the Intestinal Mucosal Barrier and Intestinal Diseases.

Zinc is an essential trace element for living organisms, and zinc homeostasis is essential for the maintenance of the normal physiological functions of cells and organisms. The intestine is the main location for zinc absorption and excretion, while zinc and zinc homeostasis is also of great significance to the structure and function of the intestinal mucosal barrier. Zinc excess or deficiency and zinc homeostatic imbalance are all associated with many intestinal diseases, such as IBD (inflammatory bowel disease), IBS (irritable bowel syndrome), and CRC (colorectal cancer). In this review, we describe the role of zinc and zinc homeostasis in the intestinal mucosal barrier and the relevance of zinc homeostasis to gastrointestinal diseases.