Zn Supplementation Research Articles

Effect of Zinc on Blood Biochemical and mTOR Gene Expression in Rats with Polycystic Ovarian.

Zinc (Zn) is a significant element of the reproductive system and is associated with several enzymes that regulate different metabolic pathways. Organic Zn can significantly affect polycystic ovarian syndrome (PCOS) pathogenesis. Insulin resistance (IR) is a common complication of PCOS. Mammalian target of rapamycin (mTOR), which controls crucial cell functions, is regulated by insulin and nutrients. It has two complexes, namely, mTORC1 and mTORC2. mTOR associates with its binding partner's regulatory associated protein of mTOR (Raptor) and rapamycin-insensitive companion of mTOR (Rictor), which form these distinct complexes, respectively, and is activated in PCOS. This research aimed to evaluate the effect of Zn on the expression of mTOR signaling genes (Raptor and Rictor) and IR in PCOS model rats. Different Zn supplements, including standard diet (SD): (control - or + , SD without supplementation), Zn25, Zn75, and Zn175 (daily given three levels of 25, 75, and 175mg Zn methionine (ZnMet)/kg for 6weeks, respectively), were applied to the control and PCOS groups. Fasting glucose (FG), fasting insulin (FI), IR indices, and Raptor and Rictor expression levels were measured in both groups. The results showed that PCOS induction dramatically increased FG, FI, IR indices, and mTOR-related gene expression; however, different Zn supplementation concentrations, especially at 75mg/kg, reduced the effects of PCOS induction. Organic Zn collectively exerted positive effects on Estradiol Valerate (EV)-induced PCOS rats by reducing IR and mTOR signaling gene (i.e., Raptor and Rictor) expression. Moreover, this study revealed a correlation between Zn and IR. Therefore, Zn supplementation could be a valuable therapeutic method for treating PCOS.

Phytase Improves Zinc Utilization by Broiler Chickens

The study aimed to evaluate phytase effects on the availability of zinc (Zn) from corn and soybean meal feeds for broiler chickens, whereas, in parallel, Zn requirements were investigated. A total of 640 Cobb × Cobb 500 male chicks were fed a Zn-deficient diet (18.87 ± 0.87 mg/kg Zn) until 7 days of age. The experiment was a 2 × 5 factorial with 10 treatments (feeds with or without phytase × 5 increasing dietary Zn levels) with 8 replications of 8 birds each. Supplemental Zn sulfate heptahydrate was used (measurements of the Zn analyzed in the feeds were 30.1 ± 0.73, 61.6 ± 0.13, 90.4 ± 1.60, 123.6 ± 1.99, and 151.9 ± 1.84 mg/kg, respectively). There were no interactions between phytase and Zn for any evaluated response. Phytase improved broiler performance and increased plasma myo-inositol, Zn content in the liver and tibia, Zn retention, and digestible energy (p < 0.05). No significant impact of dietary Zn was found on broiler performance (p > 0.05) except for Zn excretion and tibia Zn content. Adding phytase at 4000 FYT increased the apparent ileal Zn digestibility by 98% and Zn retention by 13.7%, whereas Zn supplementation of up to 151.9 mg/kg did not impact broiler performance.

Magnesium and Zinc as Vital Micronutrients Enhancing Athletic Performance and Recovery – a Review

Introduction and Aim of the ReviewMagnesium and zinc are vital for cellular metabolism and maintaining homeostasis, playing a particularly significant role for athletes. Magnesium, which is largely stored in bones and muscles, is essential for protein synthesis. Zinc, a critical trace element found in muscle and bone tissue, participates in over 300 enzymatic reactions, acts as an antioxidant and making both minerals crucial for physical performance. This study aims to explore the physiological role of magnesium (Mg) and zinc (Zn) in the context of athletic performance and to examine their impact on energy metabolism, muscle function, protein synthesis and potential benefits of Mg and Zn supplementation for improving athletic outcomes and post-exercise recovery. MethodsA comprehensive review of scientific literature was conducted through a thorough search of the PubMed database to explore the latest findings on the utility of magnesium and zinc in sports. Only articles in English were considered. Current KnowledgeThe review results indicate that Mg and Zn play critical roles in energy metabolism, muscle and immune system health. Mg deficiency can impair muscle function and reduce endurance, while its supplementation supports muscle relaxation, cardiovascular health, and respiratory efficiency. Although required in small amounts, Zn is indispensable for enzymatic activity, protein synthesis, hormonal balance, and muscle recovery, making it vital for post-exercise recovery and immune response modulation. ConclusionsAvailable data suggest that Mg and Zn supplementation may positively influence athletic performance, energy metabolism, and recovery post-exercise, though further research is needed to establish specific supplementation guidelines. This review provides a foundation for developing supplementation strategies aimed at enhancing athletic performance and supporting healthy recovery.

Drought stress mitigation and improved yield in Glycine max through foliar application of zinc oxide nanoparticles

The impact of climate change on agricultural production is apparent due to declining irrigation water availability vis-à-vis rising drought stress, particularly affecting summer crops. Growing evidence suggests that zinc (Zn) supplementation may serve as a potential drought stress management strategy in agriculture. Field studies were conducted using soybean (Glycine max var. Saba) as a model crop to test whether foliar application of zinc oxide nanoparticles (ZnO-NPs) or conventional Zn fertilizer (ZnSO4) would mitigate drought-related water stress and improve soybean yield. Each fertilizer was foliar applied twice at a two-week interval during the flowering stage. Experiments were concurrently conducted under non-drought conditions (70% field capacity) for comparison. Results showed drought significantly reduced relative water content, chlorophyll-a, and chlorophyll-b in untreated control plants by 35.7%, 47.7%, and 41.4%, respectively, compared to non-drought conditions (p < 0.05). Under drought conditions, ZnO-NPs (200 mg Zn/L) led to 33.1% and 20.7% increase in chlorophyll-a and chlorophyll-b levels, respectively, compared to ZnSO4 at 400 mg Zn/L. Likewise, catalase, peroxidase and superoxide dismutase activities increased by 62.6%, 39.5% and 28.5%, respectively, with ZnO-NPs (200 mg Zn/L) under drought compared to non-drought conditions. Proline was significantly increased under drought but was remarkably suppressed (~ 54% lower) with ZnO-NPs (200 mg Zn/L) treatment. More importantly, the highest seed yield was observed with ZnO-NPs (200 mg Zn/L) treatment under drought (39% higher than untreated control) and non-drought (79.4% higher than control) conditions. Overall, the findings suggest that ZnO-NPs could promote seed yield in soybean under drought stress via increased antioxidant activities, increased relative water content, decreased stress-related proline content, and increased photosynthetic pigments. It is recommended that foliar application of 200 mg Zn/L as ZnO-NPs could serve as an effective drought stress management strategy to improve soybean yield.

Mitigating Mercury Accumulation and Enhancing Methylmercury Degradation in Rice: Insights from Zinc-Mercury Antagonism at Molecular Levels.

Zn as an essential element has the potential to protect against mercury (Hg) toxicity in rice. However, the antagonistic effects between Zn and Hg in rice and their mechanisms remain unknown. This study proposed a promising strategy for Zn application to mitigate Hg accumulation and toxicity in rice and revealed the underlying molecular mechanisms. The findings revealed that Zn supplementation significantly reduced the uptake and transportation of both IHg and MeHg in rice, thereby alleviating Hg phytotoxicity. In particular, Zn profoundly mitigated Hg-induced oxidative damage to rice, which was attributed to the redistribution of Hg and Zn in the root and Zn competing for binding sites on glutathione. The co-binding of Zn2+ and HgCH3+ within the same active sites of Zn transporters can promote the transfer of regions with a high charge density distribution at the highest occupied molecular orbital (HOMO) level. This process facilitates proton attack on the Hg-C bond, thereby enhancing MeHg demethylation in rice. By elucidating the molecular mechanisms of Zn, IHg, and MeHg interactions in rice, this study offers new insights for developing efficient strategies to mitigate Hg risks while boosting the Zn content in crops, thereby fortifying food safety.

More than a contaminant: How zinc promotes carbonate-mineralizing bacteria metabolism and adaptation by reshaping precipitation conditions

Although microbial-induced carbonate precipitation (MICP) technology is both environmentally friendly and cost-effective, its efficiency is constrained by challenges such as low bacterial activity and heavy metal stress. This study explored the enhancement of mineralization efficiency by incorporating zinc (Zn) into the cultivation system of carbonate-mineralized bacteria. All Zn salts at a concentration of 30 μmol/L significantly enhanced the density and heavy metal resistance of bacterial cells, while also promoting CO2 hydration efficiency. The activities of urease and carbonic anhydrase (CA) were significantly elevated after treatment with 30 μmol/L ZnCl2 and Zn(C3H5O3)2 (ZnL) compared to the control. The results from qRT-PCR and ELISA confirmed that ZnL exhibited a stable biological effect on CA gene expression. Through the analysis of surface chemistry of cells and the subcellular distribution pattern of cadmium (Cd), it was observed that Zn supplementation maintained the cell surface stability and strengthened the cellular barrier against Cd uptake. SEM, FTIR and XRD results further confirmed that Zn supplementation significantly increased the complexity of the mineral morphology, resulting in a more stable crystal structure of CdCO3. This study offers additional theoretical and technical backing, opening a new avenue for the practical application of MICP technology in heavy metal remediation.

Zinc promotes microbial p-coumaric acid production that protects against cholestatic liver injury.

Cholestatic liver disease (CLD) is a common liver disorder with limited treatment options. Here, we demonstrate that zinc (Zn) supplementation can alter the gut microbiome to mitigate cholestatic liver injury. Oral Zn altered the microbiota of mice and humans (this study was registered at clinicaltrials.gov [NCT05597137]), increasing the abundance of Blautia producta (B.producta) and promoting the generation of p-coumaric acid. Additionally, p-coumaric acid concentrations were negatively correlated with liver injury parameters in CLD patients. In mice, the protective effects of Zn were partially mediated by p-coumaric acid, which directly bound to nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2) and suppressed the production of reactive oxygen species (ROS) in hepatocytes, thus preventing hepatocyte cell death and liver damage. Additionally, knocking out the histidine ammonia-lyase, which catalyzes the conversion of tyrosine to p-coumaric acid in B.producta, blunted the protective effects of Zn. These findings highlight a host-microbiota interaction that is stimulated by Zn supplementation, providing potential benefits for CLD.

Zinc-modulated bidirectional copper transfer across the blood-brain barrier in a porcine brain capillary endothelial cell culture model system

The blood-brain barrier (BBB) serves as a crucial interface, regulating the transfer of trace elements (TEs) such as copper (Cu) and zinc (Zn) between the bloodstream and the brain. Cu and Zn are essential for maintaining neural function and enzymatic processes. Understanding the interplay of Cu and Zn with the BBB is crucial for elucidating their roles in neurological health and disease. This study investigates the bidirectional transfer of Cu across the BBB and examines the impact of Zn supplementation on this process using a porcine brain capillary endothelial cell (PBCEC) model. Transendothelial electrical resistance (TEER) and capacitance measurements confirmed barrier integrity upon TE exposure, while quantification of Cu and Zn concentrations via inductively coupled plasma-tandem mass spectrometry (ICP-MS/MS) in the culture medium provided essential baseline data. Transfer studies revealed significant increases in basolateral (brain side) Cu concentrations after apical (blood side) Cu incubation, with additional Zn supplementation reducing Cu transfer from apical to basolateral compartments. Conversely, Zn incubation showed no effect on basolateral-to-apical Cu transfer. Surprisingly, it was found that Cu also transferred significantly to the apical compartments when incubated basolaterally, and with slightly higher permeability coefficients than vice versa, indicating a potential role of PBCECs in regulating Cu transport both from blood to brain and from brain to blood. These findings suggest a bidirectional Cu trafficking across PBCECs, only slightly influenced unidirectionally by Zn supplementation, highlighting the intricate interplay between TEs at the BBB. Importantly, no alterations in barrier integrity were observed, underscoring the physiological relevance of the experimental conditions. Overall, this study sheds light on the complex dynamics of Cu and Zn transfer at the BBB, emphasizing the need for comprehensive investigations into TE interactions for a deeper understanding of brain TE homeostasis.

Evaluation of Two Levels of Trace Mineral Supplementation to Beef Calves Prior to Weaning.

In this 2-year study, approximately 84 days prior to weaning, 24 calves/year (Angus × Hereford) were randomly assigned to one of two treatments: trace mineral (Cu, Se, and Zn) supplementation following NASEM (2016) recommendations (Control) or trace mineral supplementation above NASEM (2016) recommendations (Super). Calves were individually fed, and trace minerals were provided in 0.5 kg of dry distiller's grains three times weekly. Body weight (BW), blood, and liver samples were collected on d 0 and at weaning (d 84). Additional BW and blood samples were collected post-weaning on d 85, 87, 88, 91, 95, and 99 during the preconditioning phase. Initial liver concentrations of Se, Cu, and Zn were similar between treatments (p ≥ 0.69). At weaning, a year effect (p < 0.001) and a tendency for treatment × year effect (p = 0.09) were observed for Cu liver concentration. In year 2, but not in year 1, calves assigned to the Super treatment tended to have greater liver Cu concentration than calves assigned to the Control treatment. Except for Cu, a notoriously limited trace mineral in multiple geographical locations, the supplementation of trace minerals above the NASEM (2016) recommendations did not improve the mineral status of calves in this environment.

Literature study on Zn supplementation in feed for the growth enhancement of nile tilapia (Oreochromis niloticus)

Micro minerals play a crucial role in the physiological processes of fish, acting as enzyme cofactors and stabilizing enzyme and protein structures. One of the essential micro minerals needed in the body is zinc (Zn). Zinc is utilized for various physiological processes, including the maintenance of enzymatic processes within the fish's body. The aim of this literature review is to analyze the optimal level of zinc supplementation in feed to enhance the growth performance of Nile tilapia (Oreochromis niloticus), based on the reported findings of conducted research. The literature sources were obtained from accredited national journals, international journals, research outcomes, theses, and dissertations over the past 20 years. The results of this literature review indicate that zinc supplementation in feed can have a positive impact on overall fish growth by increasing digestive enzyme activity, particularly protease enzymes. The level of zinc supplementation in fish is influenced by several factors, including: 1) fish size, 2) feed consumption quantity, and 3) duration of maintenance. The optimal dietary zinc intake for Nile tilapia growth is reported to be in the range of 20–50 mg/kg. Keywords: growth, literature study, nile tilapia, zinc ABSTRAK Mikro mineral memiliki peran yang sangat penting dalam fisiologi tubuh ikan yang berfungsi sebagai kofaktor enzim dan menjadi penstabil struktur enzim maupun protein. Salah satu mikro mineral yang memiliki fungsi penting dan diperlukan dalam tubuh adalah unsur seng (Zn). Unsur Zn digunakan untuk proses fisiologis termasuk pemeliharaan proses enzimatik dalam tubuh ikan. Tujuan studi pustaka ini adalah menganalisis tingkat suplementasi Zn yang optimum dalam pakan untuk meningkatkan performa pertumbuhan ikan nila Oreochromis niloticus berdasarkan laporan hasil-hasil penelitian yang telah dilakukan. Sumber pustaka didapatkan dari jurnal nasional terakreditasi, jurnal internasional, hasil penelitian, tesis, dan disertasi pada kurun waktu 20 tahun terakhir. Hasil studi pustaka ini menunjukkan bahwa suplementasi Zn dalam pakan dapat memberikan pengaruh positif pada pertumbuhan ikan secara umum melalui peningkatan aktivitas enzim pencernaan terutama enzim protease. Tingkat suplementasi Zn pada ikan dipengaruhi oleh beberapa faktor di antaranya: 1) ukuran ikan 2) jumlah konsumsi pakan dan 3) lama pemeliharaan. Nilai asupan Zn yang memberikan pertumbuhan optimum pada ikan nila adalah sebesar 20–50 mg/kg. Kata kunci: ikan nila, pertumbuhan, seng, studi pustaka

Synergistic Effects of Hydroxychloride and Organic Zinc on Performance, Carcass Characteristics, Liver and Tibia Mineral Profiles of Broiler Chickens

AbstractThis study investigated the potential synergism between hydroxychloride and organic zinc (Zn) at different levels on performance and carcass characteristics of broiler chickens. There were seven experimental diets including a negative control diet without any supplemental Zn, and six diets with 80 mg/kg added Zn in the forms of ZnSO4, hydroxychloride Zn (HCZ) and organic Zn (ORZ), and a combination of HCZ and ORZ at 40 mg/kg HCZ + 40 mg/kg ORZ (HCZ40-ORZ40), 55 mg/kg HCZ + 25 mg/kg ORZ (HCZ55-ORZ25), and 70 mg/kg HCZ + 10 mg/kg ORZ (HCZ70-ORZ10). Each diet was replicated eight times with 17 chicks per replicate. On day 35, HCZ70-ORZ10 and HCZ40-ORZ40 diets resulted in the highest body weights (P &lt; 0.05). Throughout the entire production period (1–35 days), all HCZ and ORZ diets significantly improved feed conversion ratio (FCR) compared to PC (P &lt; 0.05), with HCZ40-ORZ40 showing the lowest FCR. Breast meat yield was lower in NC-fed birds, while HCZ80 and HCZ70-ORZ10 groups had the lowest abdominal fat weight (P &lt; 0.05). Liver and gizzard weight, tibia breaking strength, and ash percentage, footpad dermatitis, and hock burns were not affected. Tibia Zn content was higher in HCZ or ORZ-supplemented birds compared to NC (P &lt; 0.05), whereas other minerals in tibia and liver were unaffected. In summary, the absence of supplemental Zn negatively affects growth and carcass characteristics, whereas replacing ZnSO4 with HCZ, ORZ, or their combinations improves bodyweight and FCR. HCZ70-ORZ10 and HCZ40-ORZ40 were identified as optimal combinations for maximizing feed efficiency.

373 Effect of Cu and Zn contents in growing finishing pig diets on animal performance and Cu and Zn content in manure, according to three manure management chains

Abstract Copper (Cu) and zinc (Zn) are essential nutrients for swine. However, as pigs have a low retention rate for these elements, more than 90% of ingested Cu and Zn are excreted, mainly in feces. After spreading manure, these trace elements could accumulate in the soil and potentially have negative environmental effects. Moreover, Cu and Zn are also limited natural resources that should be preserved. A better understanding of the behavior of these elements throughout the feed-animal-effluent-treatment continuum according to feed composition and manure management chain is thus required to propose alternative ways to reduce these environmental impacts. Three feeding strategies differing in their Cu and Zn contents were compared in 72 growing-finishing pigs raised in individual pens [from 24.3 ± 3.3 up to 110 ± 9.0 kg body weight (BW), one-half males; and one-half females] a first diet with Cu and Zn at maximum EU regulation levels (20 and 100 ppm of Cu and Zn, respectively; REG), a second diet without any Cu and Zn supplementation (5 ppm Cu, 30 ppm Zn; WS) and a third diet with Cu and Zn at an intermediary level (10 and 50 ppm of Cu and Zn; INT). Cu and Zn were supplemented as Cu2O (CoRouge, Animine) and ZnO (HiZox, Animine), respectively. Eighteen additional finishing pigs (6 per diet) were raised in digestibility cages for excreta collection over 10 d, and their feces were submitted to two types of manure treatment: anaerobic digestion (AD) and composting with straw. Over the entire experimental period, the dietary Cu and Zn content did not influence growth performance of pigs. The Cu and Zn concentrations of the feces decreased linearly (P &amp;lt; 0.001) with dietary content from 191 and 834 (REG) up to 63 and 359 (INT) and 40 and 213 (WS) mg Cu and Zn/kg dry matter (DM) respectively. After both manure treatments, the degradation of the organic matter resulted in a significant increase (twice as much) in Cu and Zn concentration per kg of DM. Feeding strategy appears to be the main lever to reduce the Cu and Zn content of effluents. However, in the context of the diversification of manure management strategies, it is also important to take into account the effect of the effluent collection and treatment chain (e.g., spreading of raw slurry, phase separation, anaerobic digestion, composting), which has also an impact on the behavior of Cu and Zn and consequently on the risk for the environment.

353 Zinc supplementation prior to transit and transit duration effects on feedlot performance and muscle fatigue of beef steers: Part I – Performance and Muscle Fatigue

Abstract This study investigated zinc (Zn) as a mitigation strategy for transit-induced muscle fatigue. Recently weaned Angus-cross steers (n = 80) were stratified by body weight (BW = 265 ± 18.0 kg) to a 2×2 factorial. Dietary (DIET) treatments of no supplemental Zn (Zn0) or 100 mg supplemental Zn/kg DM (Zn100; Zn as ZnSO4), were fed for 42 d before transit. Along with a transit duration (DUR) of 8 h (~707 km; 8H) or 18 h (~1,608 km; 18H) on d 0. Upon return, and for 56 d post-transit, all steers received Zn100. Individual feed disappearance was monitored using GrowSafe bunks (1 bunk/pen; 5 steers/pen). Body weights were collected on d -42, -41, -1, 0 (on truck), 1 (off truck), 2, 7, 28, 55, and 56. Blood samples for analysis of non-esterified fatty acid (NEFA) and serum L-lactate were collected on d -1, 1, 2, and 7. Data were analyzed via ProcMixed of SAS (experimental unit = steer; 15 to 20/treatment) as a 2 × 2 factorial, with fixed effects of DIET, DUR, and the interaction. Individual initial (d -42) BW was used as a covariate in BW analysis. Average DMI of d -11 to d -2 (pre-trucking) was used as a covariate in post-transit DMI analysis. Blood parameters were log-transformed and analyzed as repeated measures with repeated effect of day. Pre-transit (d -1) concentrations were used as a covariate. Pre-transit average daily gain (ADG) and dry matter intake (DMI) were greater (P ≤ 0.02) and feed efficiency (gain to feed; G:F) tended to be greater (P = 0.10) in Zn100 vs. Zn0. BW on d -1 and 7 (P = 0.01) was greater for Zn100 than Zn0. There was a DIET effect and DUR tendency on post-transit G:F where Zn0 was greater than Zn100 (P ≤ 0.01) and 18H tended to be greater than 8H (P = 0.05). 56-d post-transit ADG was least for Zn100-8H (DIET×DUR, P = 0.02). Post-transit DMI was greatest for Zn0-8H with Zn100-8H being the lowest and other treatments being not different (DIET × DUR, P = 0.04). Diet did not affect L- lactate or NEFA concentrations (P &amp;gt; 0.13). NEFA was greater for 18H vs. 8H on d 1 and 2 but less on d 7 (DUR×DAY, P &amp;lt; 0.01). There was a DUR×DAY effect (P ≤ 0.01) for L-Lactate where 8H tended to be greater than 18H on d 1, but by d 2 8H was lesser than 18H, and on d 7 they were not different. In conclusion, longer transit duration increases some indicators of muscle fatigue and Zn supplementation improved pre-transit performance. Receiving Zn supplementation after trucking also improved the post-transit performance of those not previously supplemented with Zn.

354 Zinc supplementation prior to transit and transit duration effects on feedlot performance and muscle fatigue of beef steers: Part II – Feeding Behavior

Abstract This study assessed the effects of supplemental Zn on cattle feeding behavior after varying transit duration. Angus crossbred steers (80; 265 ± 18 kg) were used in a 2 × 2 factorial design. Steers were assigned to a dietary Zn treatment (DIET) and transit duration (DUR; d 0): Zn0 (no supplemental Zn) or Zn100 (100 mg Zn/kg DM; supplemented as ZnSO4, starting d -42 relative to transit) and short duration (8H; 8 h transit; 707 km) or long duration (18H; 18 h transit; 1608 km). Steers were fed ad libitum via GrowSafe bunks (GrowSafe Systems Ltd., Airdrie, AB, Canada), and steer was experimental unit (n = 1 bunk/pen; n = 5 steers/pen). On d 0, steers were stratified to trailer compartments across diets. The 8H and 18H groups departed at 1000 and 1300 h and returned at 1800 and 0700 h to pre-transit pens, respectively. Following transit, all steers received Zn100. Utilizing GrowSafe Behavior module, a feed event was characterized as a reading with &amp;lt; 300 s interruption with head down (FE-HD; recorded in seconds) and count (number of HD events). Intake rate (g/s) was feed consumed per FE-HD divided by FE-HD duration. Data for the 6-d post transit were analyzed as a complete randomized design utilizing PROC MIXED of SAS 9.4 (SAS Inst. Inc., Cary, NC) with fixed effects DIET, DUR, and DAY as repeated. Pre-transit values served as a covariate. During the week prior to transit, there was a DUR effect for FE-HD average and intake rate (P ≤ 0.03) where 8H had longer FE-HD but reduced intake rate than 18H. There was also a tendency for Zn100 to consume more feed per FE pre-transit (P = 0.07). Post-transit, both average intake and FE-HD average increased with days post-transit (DAY; P ≤ 0.01). Additionally, a DIET × DUR effect was observed for FE-HD count (P = 0.01) where 100 was greater than 0 within 18H and 0 was greater than 100 in 8H. A tendency for a TRT × DAY effect was noted for FE-HD count (P = 0.07) driven by Zn0 decreasing from d 3 to 4. A DUR × DAY effect (P = 0.02) was also noted for FE-HD count where 18H was greater on d 2, 4, and 5. A DUR × DAY effect was observed for FE-HD average (P = 0.01) driven by a d 3 difference where 8H was greater than 18H. Conversely, a DUR × DAY effect was observed for intake rate (P = 0.01) where 18H was greater on d 2, 3, and 6. These data indicate both transit duration and dietary Zn concentration influenced animal behavior post-transit.

170 Understanding how zinc and manganese interact with the hormones found in anabolic implants to alter growth of bovine satellite cells

Abstract It has been well established in both in vitro and in vivo models that the hormones found in anabolic implants [estradiol (E2) and trenbolone acetate (TBA)] positively impact skeletal muscle growth. Previous research has demonstrated that treating primary bovine satellite cells (BSC) with E2 or TBA results in increases in proliferation and protein synthesis and decreases in protein degradation, leading to enhanced skeletal muscle growth. This improved skeletal muscle growth occurs through partially defined pathways, but many unknowns remain. More recently, research has emerged demonstrating that strategic supplementation of specific trace minerals (TM) may further augment the positive effects of E2 and TBA on skeletal muscle growth. There are many ways through which the complex signaling pathways induced by the hormones found in anabolic implants may interact with TM to further enhance skeletal muscle growth. Zinc (Zn) and manganese (Mn) are two of the TM that we have recently investigated. Zinc is the most utilized metal in biological processes and supports animal growth through critical roles in the functions of IGF-1, GH, and DNA synthesis. Manganese is an essential TM providing catalytic activity to enzymes involved in protein glycosylation, nitrogen metabolism, and antioxidant capacity. However, additional research is needed to determine if hormones and TM interact to impact growth of skeletal muscle, specifically. As such, the goal of recent research that has been conducted by our group is to utilize an in vitro primary BSC model to determine whether hormones and TM interact to alter differentiation and protein synthesis. Preliminary research from our group assesses the impacts of varying, physiological concentrations of Zn or Mn on differentiation and protein synthesis of primary BSC cultures that have also been treated with or without the hormones found in anabolic implants. These preliminary findings demonstrate that while there seems to be no interaction between Zn and hormones in differentiating BSC, supplemental Zn on the higher end of physiologically relevant concentrations has a positive effect on signaling pathways involved in growth, protein turnover, skeletal muscle differentiation, and mineral transporters. However, it appears that Zn and Mn each interact with hormones to positively augment protein synthesis in primary BSC cultures. A deeper understanding of the relationship these TM and others may have with hormones will allow for more strategic supplementation practices that can potentially improve skeletal muscle growth.

20 Trace metal homeostasis in growing cattle

Abstract Apparent trace metal absorption and tissue retention upon incremental levels of supplemental Zn, Cu, and Mn were studied in growing cattle. A total of 60 Holstein bulls were enrolled for the study and fed for 28 d a diet consisting of barley straw (15%), molasses (10%) and pelleted concentrate (75%; Zn = 78 ppm, Cu = 15 ppm, Mn = 91 ppm). Thereafter, 20 bulls were randomly selected and slaughtered for determination of baseline tissue trace metal composition. The remaining 40 bulls [body weight (BW) = 394 ± 20 kg] were then blocked based on BW in 8 blocks of 5 bulls each. Bulls within a block were randomly assigned one of the diets differing in supplemental levels of Zn, Cu, and Mn (all from sulfate form) with the following dietary contents of Zn, Cu and Mn, respectively: No supplement (38, 7, and 47 ppm), Dose 1 (61, 11, and 68 ppm), Dose 2 (78, 15 and 91 ppm), Dose 3 (123, 26, 136 ppm) or Dose 4 (195, 43, and 214 ppm). These diets were fed for 12 wk, and complete collection of feces and urine were performed on wk 4, 8 and 12 for assessment of trace metals balance and apparent absorption. Gastrointestinal tissues, whole organs (heart, liver, spleen, and kidney), bile, cervical vertebra, and tibia were collected at slaughterhouse from all bulls. All samples were dried, ground, and analyzed for minerals. Data were processed using dietary treatment as a continuous variable and also as categorial variable. Both approaches adjusted for the fixed effect of block (Proc Mixed, SAS 9.4). Whole-body Zn, Cu and Mn balance quadratically increased (P &amp;lt; 0.05) with supplementation, with a significantly higher values for Dose 4 compared with all other dietary treatment (Figure 1, P &amp;lt; 0.05). Dose 4 also led to a 2-fold increase in urinary Zn and Cu excretions (P &amp;lt; 0.05), and a 4-fold increase in urinary Mn excretion (P &amp;lt; 0.01). Although magnitudes of change were moderate (8 to 15%), increasing dietary Zn supply linearly increased spleen Zn content (P = 0.03), and tended to increase ruminal and hepatic Zn content (P &amp;lt; 0.10). Hepatic Cu linearly increased from 264 to 667 mg/kg DM with increasing dietary Cu supply (P &amp;lt; 0.01), whereas Cu concentration in bile only increased at Doses 4 and 5 (P &amp;lt; 0.01). Increasing Mn supply resulted in quadratic increase of ruminal and biliary Mn content from 340 to 1140 mg/kg DM, and from 0.32 to 1.38 mg/L, respectively. Small intestine and cecum Mn concentrations linearly and quadratically increased (about 2-fold increase, P &amp;lt; 0.05) with incremental supply of Mn. Homeostatic regulation mechanisms were apparently overwhelmed at the greatest Zn, Cu and Mn supplementation levels evaluated in this study.

28 Integrating homeostasis in practical mineral supplementation recommendations

Abstract A long-established objective in ruminant nutrition is an accurate supply of the 4 main trace metal nutrients Zn, Cu, Mn, and Fe, respecting bioavailability, nutritional interactions, and nutrient tolerance. Although, current dietary supplementation practices, justified by the multiple uncertainties of trace metal supply, results in dietary levels that widely exceed nutritional guidelines. Additionally, reference feeding recommendations are defined assuming fixed and highly conservative uptake coefficients, an approach that disregards the opportunity, and limitations, of absorptive regulation, the main homeostatic mechanism of these nutrients. Mitigating deficiency risks by generous supplementation can result in a generally overlooked risk, exceeding tolerable trace metal availability. Complete nutrient balance studies have recently described the overwhelming homeostatic downregulation of trace metals at dietary levels that are not uncommon in practice. This finding calls for a novel approach to define supplementation that resolves this conundrum of trace metal adequacy. This approach integrated 3 elements: a stochastic analysis of native dietary supply; a stochastic analysis of net nutrient requirements; and the identification of the upper and lower boundaries of homeostatic regulation for these 4 nutrients in the bovine species. This last, aims to resolve the main limitation of current dietary guidelines, using the potential maximum uptake rates in homeostatic upregulation, and the minimum uptake rates achievable by downregulation, instead of assuming fixed uptake rates. As result, this approach delivers dietary supply ranges of adequate supply, instead of a minimum dietary level to meet dietary adequacy. The probability distribution of nutrient supply was determined by dry-matter intake variability, diversity in dietary composition, and variability of nutrient occurrence in feedstuffs. The probability distribution of net nutrient requirements was defined by the variability of the components of a classic factorial requirement approach applied to different animal conditions. A maximum apparent absorption efficiency was determined to define lower supply boundaries using published datasets. Upper boundaries were defined as the dietary supply level beyond which apparent absorption empirically has shown to exceed net requirements. As expected, this risk-based approach resulted in much lower supplementation recommendations than current reference models. However, it supports the value of preventive supplementation of Zn and Cu to growing and lactating animals, and Cu to non-lactating non-growing cows. This assessment also indicates merit in Mn supplementation to growing bovines. Furthermore, it confirms that under all circumstances native dietary Fe meets nutritional needs, but it also illustrates a tolerance risk to native Fe supply under multiple productive scenarios. Most interestingly, this analysis illustrates the risk of exceeding trace metal tolerance boundaries with common levels of supplementation under common conditions. This approach offers a novel perspective to trace metal supplementation, pointing at an opportunity to improve nutritional adequacy by reconsidering supplementation practices.

26 Trace minerals to improve bull fertility

Abstract Bull fertility is paramount for reproductive success in cow-calf production systems and there are a variety of factors that influence bull fertility. Trace mineral requirements and recommendations have been established for growing and finishing steers, as well as lactating and pregnant cows, yet no specific requirements have been established for young or mature beef bulls. Nonetheless, trace minerals have been shown to have an important role in sexual maturation and semen quality of ruminants. Research performed in rams indicates that zinc deficiency results in reduced testicular development, decreased testicular concentrations of testosterone, and impaired development of seminiferous tubules. Deficiency of Zn has also been reported to negatively impact male fertility in humans, where men diagnosed with infertility responded positively to Zn supplementation. In growing bulls, diets with greater concentrations of organic forms of Zn, Cu, and Mn, tended to result in earlier attainment of puberty compared with control diets containing inorganic minerals. Furthermore, greater liver concentrations of Zn have been negatively correlated with sperm acrosomal damage in growing bulls, based on flow cytometry analyses. More recent research indicates that the use of hydroxichloride-based trace minerals results in greater liver concentrations of Zn and Cu compared with sulfate sources. While evidence indicates that trace mineral status has an important role in bull fertility, further research is required to better understand the contributions of trace minerals to semen quality. In addition, investigating the impact of trace mineral sources with greater bioavailability on semen quality may result in the development of practical recommendations that optimize bull fertility.

Zinc amendment as an effective tool in the management of cadmium toxicity: a case study with Amaranthus cruentus L

The unmanaged waste disposal, coupled with the increased industrialization and urbanization, has aggravated the problem of heavy metal contamination in the environment, especially in the agricultural soils. In view of this, the present study was planned to evaluate the effectiveness of zinc (Zn) in the amelioration of cadmium (Cd) toxicity in plants, thereby sustaining the crop productivity in near future. The experiment was performed in two parts. The first part focused on calculating the EC50 (half-effective concentration) of Cd, for which the potted experimental plants (Amaranthus cruentus L.) were treated with different doses of Cd (10, 20, 30, 40, and 50 mgL−1). In the second part, the EC50 Cd dose was combined with different Zn doses (100, 200, 300, 400, and 500 mgL−1) and the effect of Zn supplementation on Cd exposed plants was studied by evaluating the response of different biochemical, physiological and yield parameters. The EC50 Cd dose was calculated to be 26.5 mgL−1. Plant yield increased significantly with reduced Zn dosages. Biochemical parameters improved more than physiological parameters after Zn treatment in Cd-stressed plants. At higher Zn doses, its toxic effects exacerbate Cd toxicity. The study indicates that Zn partially decreases Cd toxicity in Amaranthus plants. The results suggest that 300 mgL−1 Zn dose was sufficient to bring about maximum recorded mitigation of Cd toxicity. However, since the synergistic effects of high doses of Zn with Cd cannot be ruled out, the selection of the applied Zn dose should be carefully selected.

Zinc Enhances Cadmium Accumulation in Shoots of Hyperaccumulator Solanum nigrum by Improving ATP-Dependent Transport and Alleviating Toxicity.

Solanum nigrum is a cadmium (Cd) and zinc (Zn) accumulator with potential for phytoextraction of soil contaminated with heavy metals. However, how Zn affects Cd accumulation in S. nigrum remains unclear. In this study, S. nigrum seedlings were treated with 100 μmol·L-1 Zn (Zn100), 100 μmol·L-1 Cd (Cd100), and the Zn and Cd combination (Zn100+Cd100) for 10 days under hydroponic culture. Compared with Cd100, the Cd content in stems, leaves, and xylem saps was 1.8, 1.6, and 1.3 times more than that in Zn100+Cd100, respectively. In addition, the production of reactive oxygen species in leaves was significantly upregulated in Cd100 compared with the control, and it was downregulated in Zn100. Comparative analyses of transcriptomes and proteomes were conducted with S. nigrum leaves. Differentially expressed genes (DEGs) were involved in Cd uptake, transport, and sequestration, and the upregulation of some transporter genes of Zn transporters (ZIPs), a natural resistance associated macrophage protein (Nramp1), a metal-nicotianamine transporter (YSL2), ATP-binding cassette transporters (ABCs), oligopeptide transporters (OPTs), and metallothionein (MTs) and glutathione S-transferase (GSTs) genes was higher in Zn100+Cd100 than in Cd100. In addition, differentially expressed proteins (DEPs) involved in electron transport chain, ATP, and chlorophyll biosynthesis, such as malate dehydrogenases (MDHs), ATPases, and chlorophyll a/b binding proteins, were mostly upregulated in Zn100. The results indicate that Zn supplement increases Cd accumulation and tolerance in S. nigrum by upregulating ATP-dependent Cd transport and sequestration pathways.