Relative bioavailability of two organic and two inorganic zinc sources fed to sheep

Preparation and characterization of garlic polysaccharide-Zn (II) complexes and their bioactivities as a zinc supplement in Zn-deficient mice

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Garlic polysaccharide-Zn (II) complexes were prepared.

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The structural characterization confirmed the formation of complexes.

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The complexes could significantly improve the health of Zn-deficient mice.

This study explored the potential of garlic polysaccharides (GPs) as a carrier for synthesizing GP-Zn (II) complexes to supplement Zn. According to the response surface analysis, the optimal preparation conditions were: mass ratio of GPs to Zn²⁺ 1:0.21, temperature 53 °C, pH 5.9 and time 148.75 min, with the maximum chelation rate of 90.11%. The chelation of GPs and Zn²⁺ involved O—H/C—O/O—C—O groups, increased crystallinity and altered absorption peaks of circular dichroism spectra, with a higher thermal stability, particle size and negative zeta potential. Compared with inorganic zinc salts, supplementation of GP-Zn (II) complexes showed enhance zinc supplementation effects in Zn-deficient mice model: increased body weight, organ index and Zn (II) levels in serum and liver, enhanced Superoxidedismutase (SOD) activity and alkaline phosphatase activity, decreased NO content and Malondialdehyde (MDA) content and improved colon and testicular morphology. Therefore, GP-Zn (II) complex can be used as a potential zinc supplement for Zn-deficient individuals.

Relative Bioavailability of Trace Minerals in Production Animal Nutrition: A Review

The importance of dietary supplementation of animal feeds with trace minerals is irrefutable, with various forms of both organic and inorganic products commercially available. With advances in research techniques, and data obtained from both in-vitro and in-vivo studies in recent years, differences between inorganic and organic trace minerals have become more apparent. Furthermore, differences between specific organic mineral types can now be identified. Adhering to PRISMA guidelines for systematic reviews, we carried out an extensive literature search on previously published studies detailing performance responses to trace minerals, in addition to their corresponding relative bioavailability values. This review covers four of the main trace minerals included in feed: copper, iron, manganese and zinc, and encompasses the different types of organic and inorganic products commercially available. Their impact from environmental, economic, and nutritional perspectives are discussed, along with the biological availability of various mineral forms in production animals. Species-specific sections cover ruminants, poultry, and swine. Extensive relative bioavailability tables cover values for all trace mineral products commercially available, including those not previously reviewed in earlier studies, thereby providing a comprehensive industry reference guide. Additionally, we examine reasons for variance in reported relative bioavailability values, with an emphasis on accounting for data misinterpretation.

Impact of trace mineral source on beef replacement heifer growth, reproductive development, and biomarkers of maternal recognition of pregnancy and embryo survival

Trace minerals are known to play important roles in early embryo development. The study objective was to determine effects of trace mineral source on heifer reproductive performance. Beef heifers (n = 129) were randomly assigned to one of two treatments. From weaning through breeding, all heifers were individually fed a basal diet supplemented with cobalt (Co), copper (Cu), manganese (Mn), and zinc (Zn) either from organic sources (COMP; Cu, Mn, and Zn amino acid complexes and Co glucoheptonate; Availa-4, Zinpro Corporation, Eden Prairie, MN) or inorganic sources (INORG; Cu, Mn, and Zn hydroxychlorides; Intellibond C, M, and Z, Micronutrients, Indianapolis, IN) and Co as CoSO₄. Blood samples and a reproductive tract score (RTS) were collected to determine pubertal status. All animals were synchronized and artificially inseminated. Pregnancy status was determined by lymphocyte gene expression, circulating concentrations of pregnancy-associated glycoproteins (PAGs), and by transrectal ultrasonography after artificial insemination. Embryonic loss was defined as when a previously pregnant animal was subsequently diagnosed not pregnant. Data were analyzed using the MIXED procedure in SAS. Puberty (P = 0.44), pelvic area (P = 0.74), RTS (P = 0.49), and estrus expression (P = 0.82) were not influenced by treatment. There was no effect of treatment (P = 0.37) or treatment by time (P = 0.19) on pregnancy, but there was a tendency (P = 0.13) for decreased embryonic loss among COMP heifers (27 ± 6%) compared to INORG heifers (38 ± 6%). There was a treatment by pregnancy status by time interaction (P < 0.01) on circulating PAG concentrations with PAG concentrations tending (P = 0.08) to be greater on day 25 among heifers in the COMP treatment compared to heifers in the INORG group. In summary, source of trace mineral did not affect puberty, RTS, pelvic area, or overall pregnancy success, but feeding complexed trace minerals tended to increase circulating PAG concentrations and embryo survival.

Zinc in Dog Nutrition, Health and Disease: A Review

Simple Summary

This work compiles the current state of knowledge regarding zinc requirements of healthy dogs and biomarkers of zinc status. To ensure an adequate zinc status, it is important to know the zinc content of foods and their bioavailability to assess the need and the ideal supplementation strategy regarding levels and sources of additives in complete dog foods. As zinc is required for enzymatic, structural, and regulatory functions in the animal body, its nutritional status has been associated with several pathologies that may be due to, or exacerbated by, a deficit of dietary zinc supply.

Abstract

Zinc is an essential trace element, required for enzymatic, structural, and regulatory functions. As body reserves are scarce, an adequate zinc status relies on proper dietary supply and efficient homeostasis. Several biomarkers have been proposed that enable the detection of poor zinc status, but more sensitive and specific ones are needed to detect marginal deficiencies. The zinc content of commercial dry dog foods has great variability, with a more frequent non-compliance with the maximum authorized limit than with the nutritional requirement. The bioavailability of dietary zinc also plays a crucial role in ensuring an adequate zinc status. Despite controversial results, organic zinc sources have been considered more bioavailable than inorganic sources, albeit the zinc source effect is more evident after a restriction period of dietary zinc. Many disorders have been associated with inadequate zinc status, not being clear whether the occurrence of the disease is the consequence or the cause. This review presents data on zinc requirements and biomarkers for zinc status, that can be applied for the development of supplementation strategies of zinc in complete pet foods. Moreover, it provides an understanding of the role zinc plays in the health of dogs, and how altered zinc status affects diseases in dogs.

Total-tract digestibility and milk productivity of dairy cows as affected by trace mineral sources

The chemical characteristics associated with different sources of Cu, Zn, and Mn such as sulfate, hydroxychloride, or organic chelate may affect the interaction between the metals and other components present within the gut of a ruminant (i.e., microorganisms and nutrients). The present study aimed to evaluate the effect of different supplemental trace mineral strategies on apparent total-tract digestibility, rumen fermentation, and dairy productivity. Using 52 Holstein cows in a replicated 4 × 4 Latin square design with periods of 21 d, 4 treatments differing in their sources of Cu, Zn, and Mn were tested: sulfate form, hydroxychloride form, a mix of sulfate and organic chelate forms (70 and 30%, respectively), and a mix of hydroxychloride and organic chelate forms (70 and 30%, respectively). Treatments were formulated to provide 15, 40, and 20 mg of supplemental Cu, Zn, and Mn, respectively, per kilogram of dry matter. This level of supplementation, together with the basal level present in forages and feed ingredients, resulted in a total average supply of 19, 79, and 84 mg of Cu, Zn, and Mn, respectively, per kilogram of dry matter. Cows had ad libitum access to a total mixed ration, which provided 15.3% of crude protein, 21.7% of starch, and 35.3% of neutral detergent fiber (NDF). Data were summarized by period with trace minerals and period as fixed effects and the repeated cow as random effect using the MIXED procedure of SAS (SAS Institute Inc., Cary, NC). Apparent total-tract NDF and crude protein digestibility was reduced (-0.8% and -1.0%, respectively) when organic chelate trace minerals were fed, whereas apparent total-tract NDF digestibility was improved (+0.8%) when sulfate trace minerals were replaced by hydroxychloride trace minerals. Cows supplemented with the hydroxychloride source had lower ruminal butyric acid concentration compared with cows fed sulfate trace minerals (13.3 vs. 14.6%). In addition, fat- and protein-corrected milk and milk fat yields were improved (+1.0 kg/d and +51 g/d, respectively) in multiparous cows when trace minerals were supplemented as hydroxychloride compared with sulfate. These effects were not observed in primiparous cows. These results confirm that trace mineral sources affect apparent total-tract digestibility and indicate that milk productivity may also be affected.

Effect of complexed trace minerals on cumulus-oocyte complex recovery and in vitro embryo production in beef cattle1,2

The objective of this experiment was to evaluate the impact of complexed trace mineral supplementation on ovum pick-up (OPU) and in vitro embryo production in lactating beef cows. Thirty days prior to fixed-time artificial insemination (FTAI; day −30), 68 postpartum cows were stratified by BW, BCS, and parity before being randomly assigned to 10 pens of either a treatment (TRT; n = 5) or a control (CNT; n = 5) group. Each group received a weekly mineral supplement allotment of 1.16 kg × week⁻¹ × cow–calf pair⁻¹ for 14 wk. Cows assigned to the TRT group received a mineral supplement that contained amino acid complexes of zinc, copper, and manganese, as well as cobalt glucoheptonate (Availa Plus; Zinpro Corp., Eden Prairie, MN, USA), while cows assigned to the CNT group received a mineral supplement that was formulated to contain similar concentrations of these trace minerals from inorganic sources. All cows were submitted to a 7 d CO-Synch + CIDR protocol on day −10 and bred using FTAI on day 0. Pregnancy diagnosis was performed on day 28 and nonpregnant cows were removed. All pregnant cows were subjected to ovum pick-up (OPU) on day 52 and 67 of gestation. Cumulus-oocyte complexes (COCs) were evaluated and graded prior to in vitro fertilization (IVF). Analysis of variance was conducted to determine effects of treatment on response variables, and pen was considered the experimental unit. Supplement consumption did not differ (P = 0.48) between treatments (1.16 ± 0.12 vs. 1.07 ± 0.15 kg of DM × week⁻¹ × cow–calf pair⁻¹ for TRT and CNT, respectively). Total COC recovery was greater (P = 0.03) from TRT when compared with CNT cows (22.4 ± 2.0 vs. 16.4 ± 1.4 COCs × pen⁻¹, respectively) and the number of COCs meeting maturation criteria was increased in TRT cows (P = 0.05) when compared with CNT cows (15.9 ± 1.6 vs. 11.8 ± 1.0 COCs × pen⁻¹, respectively). Production of transferable embryos tended to be greater (P = 0.06) for TRT than CNT cows (4.7 ± 0.6 vs. 2.7 ± 0.7 embryos × pen⁻¹, respectively). Furthermore, when expressed as a ratio, the number of recovered COCs meeting maturation criteria that were required to produce a transferable embryo tended to be lower for TRT than CNT cows (3.10 ± 0.93 vs. 7.02 ± 1.60; P = 0.06). In summary, complete replacement with complexed trace mineral improved COC recovery and in vitro embryo production when compared with inorganic forms of these trace minerals in beef cows.

Effect of Different Sources of Supplemental Zinc on Performance, Nutrient Digestibility, and Antioxidant Enzyme Activities in Lambs

Zinc (Zn) is an essential element in the growth of all animals and plays structural and catalytic roles in many enzymes and functional proteins. Two completely randomized trials were conducted to evaluate the effects of different sources of zinc on performance, nutrient digestibility, blood mineral profile, and antioxidant enzyme activities in male growing lambs on a barley-based diet. The first trial was conducted for 70 days and consisted of 30 lambs (30.8 ± 2.8 kg mean body weight, 4-5 months of age) which were randomly allocated to five treatments consisting of a basal diet (19.72 mg Zn/kg DM), or the basal diet supplemented with 30 mg Zn/kg DM, added as either zinc-sulfate (ZnSulf; inorganic), zinc-methionine (ZnMet), zinc-proteinate (ZnProt) or zinc-glycinate (ZnGly). For the second trial, to measure the effects of dietary Zn on nutrient digestibility, four lambs from each group of the first experiment were randomly allocated to individual digestibility cages for 12 days (first 7 days as an adaptation period followed by 5 days of sample collection). Among the groups, dietary Zn supplementation above basal level significantly improved average daily gain, average daily feed intake, feed/gain ratio, and superoxide dismutase activity of red blood cells (P < 0.05). Glutathione peroxidase activity of lambs supplemented with organic Zn was significantly (P < 0.05) higher than inorganic and control groups. At the end of the trial, the concentration of plasma Zn, tri-iodothyronine (T3), thyroxine (T4), and the activity of alkaline phosphatase was increased (P < 0.05) in all groups receiving Zn as compared with controls (P < 0.05). In addition, thyroxine level in animals supplemented with Zn-methionine and Zn-proteinate was greater than in animals receiving Zn-glycine and Zn-sulfate. The results of the second trial revealed that the supplementation with Zn-methionine and Zn-proteinate increased the digestibility of crude protein (CP) and acid detergent fiber (ADF) compared to groups supplemented with Zn sulfate and control (P < 0.05). All organic sources of Zn improved organic matter (OM) digestibility compared to inorganic and control (P < 0.05). Results indicated that, regardless of source, supplementation of Zn in growing lambs improved growth performance, blood antioxidants, and thyroid hormone levels. Furthermore, Zn-methionine and Zn-proteinate supplementation appeared to improve the digestibility of CP, OM, and ADF more effectively than Zn-sulfate.

The influence of zinc-methionine bioplex supplementation to pregnant and lactating sheep on selected wool parameters

The most important nutrients affecting wool production include sulfur amino acids, such as methionine, and minerals, such as zinc, and their deficiency may cause wool production decrease. The aim of this study was to evaluate an effect of zinc and methionine chelate addition on the qualitative characteristics of Merino ewes wool and zinc content in wool fibers and on their surface. Histological evaluation of fibers was also performed. The study included 22 Polish Merino ewes divided into two groups: control and experimental (0.4 g chelates daily per head). The experiment lasted for 4 months (3.5 months of pregnancy and 2 weeks of early lactation). The length, thickness and breaking force of wool fibers were higher in the experimental group compared to the control group. Higher content of zinc in wool of sheep from the experimental group was also demonstrated. The histological structure of fibers from both groups did not differ, as the content of zinc on their surface. It can be concluded on the basis of the obtained results that the addition of chelates favorably influenced the thickness compensation of wool fibers and amount of wool obtained from sheep during pregnancy and early lactation, as well as mechanical features of wool.

Zinc supplementation of Friesian cows: Effect on chemical-nutritional composition and aromatic profile of dairy products

Zinc represents an essential microelement for several biochemical mechanisms. The body's inability to store zinc necessarily requires a constant dietary supply to avoid alteration of physiological functions. The aim of the present study was to investigate the effect of dietary enrichment with zinc on chemical-nutritional and aromatic properties of milk and cheese. Thirty commercial dairy cows, balanced for parity, milk production, and days in milk, were randomly assigned to 2 groups. The control group was fed with a conventional complete diet (22 kg of dry matter/animal per day), whereas the experimental group received a daily zinc supplementation of 60 mg per kg of dry complete feed. During the experimental period, the milk yield was monitored and samples of milk and caciotta cheese were collected to obtain information about the chemical-nutritional composition and aromatic profile. Dietary zinc integration did not influence milk yield and composition, but induced a marked reduction of somatic cell count and improved the oxidative stability of ripened caciotta cheese. In both milk and cheese, the experimental group samples were characterized by a lower concentration of saturated fatty acids and an increase in oleic acid, vaccenic acid, and rumenic acid. The aromatic profile of dairy products was also positively affected by dietary zinc intake, with an increase in concentration of carboxylic acids, aldehydes, and esters. The present results suggest a positive role of zinc in improving animal health and nutraceutical properties of milk and corresponding cheese. Taking into account the analysis of volatile compounds, zinc dietary supplementation of dairy cows should contribute to the production of cheeses with interesting organoleptic properties, although more studies are necessary to confirm the consumer acceptability of these changes.

Zinc AA supplementation alters yearling ram rumen bacterial communities but zinc sulfate supplementation does not

 Despite the body of research into Zn for human and animal health and productivity, very little work has been done to discern whether this benefit is exerted solely on the host organism, or whether there is some effect of dietary Zn upon the gastrointestinal microbiota, particularly in ruminants. We hypothesized that (i) supplementation with Zn would alter the rumen bacterial community in yearling rams, but that (ii) supplementation with either inorganically sourced ZnSO4, or a chelated Zn AA complex, which was more bioavailable, would affect the rumen bacterial community differently. Sixteen purebred Targhee yearling rams were utilized in an 84-d completely randomized design, and allocated to one of three pelleted dietary treatments: control diet without fortified Zn (~1 × NRC), a diet fortified with a Zn AA complex (~2 × NRC), and a diet fortified with ZnSO4 (~2 × NRC). Rumen bacterial community was assessed using Illumina MiSeq of the V4 to V6 region of the 16S rRNA gene. One hundred and eleven OTUs were found with > 1% abundance across all samples. The genera Prevotella, Solobacterium, Ruminococcus, Butyrivibrio, Olsenella, Atopobium, and the candidate genus Saccharimonas were abundant in all samples. Total rumen bacterial evenness and diversity in rams were reduced by supplementation with a Zn AA complex, but not in rams supplemented with an equal concentration of ZnSO4, likely due to differences in bioavailability between organic and inorganically sourced supplement formulations. A number of bacterial genera were altered by Zn supplementation, but only the phylum Tenericutes was significantly reduced by ZnSO4 supplementation, suggesting that either Zn supplementation formulation could be utilized without causing a high-level shift in the rumen bacterial community which could have negative consequences for digestion and animal health.

Influence of dietary zinc on the claw and interdigital skin of sheep

Claw diseases like interdigital dermatitis and footrot threaten sheep health and are major welfare issues. Several studies mainly done in cattle suggested that zinc (Zn) supplementation may improve claw integrity. However, Zn supplements may differ markedly regarding Zn bioavailability. Zn bound to single amino acids has been shown to be more bioavailable than inorganic Zn sources. The aim of this study was to determine the effect of different Zn supplements on the integrity of the claw and interdigital skin of healthy sheep. At weaning 30 Merino lambs were randomly allocated to three different dietary treatments which were provided through the pelleted concentrates as follows: 1) no supplemental Zn (Zn0); 2) addition of 40 mg/kg Zn as Zn sulphate (ZnS); 3) addition of 40 mg/kg organic Zn as Zn amino acid complex (CZn). Barley straw and pelleted concentrates were given ad-libitum. The calculated Zn concentration of the total diet (roughage and concentrate) without supplemental Zn (Zn0) was 38 mg Zn/kg DM. The concentrates were formulated to meet the nutritional requirements for growing lambs and contained 207 g/kg DM crude protein and 12.4 MJ/kg DM metabolizable energy. After 8 weeks the lambs were slaughtered and the following specimens were collected: blood serum, liver, sole and coronary band of the claw, and interdigital skin. Serum and tissue Zn and copper (Cu) concentrations and claw hardness were determined. Routine pathohistology and electron microscopy were conducted. Franz diffusion cell system and Ki-67 immunostaining were used to determine the permeability of the interdigital skin and the keratinocyte proliferation in the basal layer of sole horn, coronary band and interdigital skin, respectively. The concentrations of Zn and Cu in serum and liver tissue as well as the Zn concentration in claw horn were not affected by dietary treatment. Zn0 lambs showed higher (p < 0.05) Cu concentrations in claw horn compared to both Zn supplemented groups. Routine pathohistology as well as electron microscopy did not show significant morphological differences between the three groups. Franz diffusion cell system proved to be a suitable method examining the interdigital skin permeability, but the group differences in this study were not significant. Dietary treatment did not affect keratinocyte proliferation in the coronary band. In the sole keratinocyte proliferation was significantly higher (p < 0.05) in the Zn0 group compared to CZn with ZnS being intermediate. Keratinocyte proliferation in the interdigital skin was significantly higher (p < 0.05) in the CZn group compared to the Zn0 with ZnS being intermediate. The results of the current experiment indicate that serum and tissue Zn concentrations and horn hardness are not affected by adding a moderate amount of Zn sulphate or Zn amino acid complex to a basal diet. However, supplemental Zn amino acid complex seems to affect keratinocyte proliferation of interdigital skin and sole horn of lambs. Effects on skin permeability should be retested using a higher number of animals prospectively.

Effects of Different Sources and Levels of Zinc on Growth Performance, Nutrient Digestibility, and Fur Quality of Growing-Furring Male Mink (Mustela vison)

The objective of this study was to investigate the effects of different sources and levels of zinc (Zn) on growth performance, nutrient digestibility, serum biochemical parameters, and fur quality in growing-furring male mink. Animals in the control group were fed a basal diet with no Zn supplementation. Mink in the other nine treatments were fed the basal diet supplemented with Zn from either grade Zn sulfate (ZnSO₄·7H₂O), Zn glycinate (ZnGly), or Zn pectin oligosaccharides (ZnPOS) at concentrations of either 100, 300, or 900 mg Zn/kg dry matter. One hundred and fifty healthy 15-week-old male mink were randomly allocated to ten dietary treatments (n = 15/group) for a 60-day trial from mid-September to pelting in December. Mink in the Zn-POS groups had higher average daily gain than those in the control group (P < 0.05). Zn source slightly improved the feed/gain (P = 0.097). N retention was increased by Zn addition (P < 0.05). Mink supplemented with dietary Zn had higher (P < 0.05) pancreas Zn level than the control group. Fur length was greater (P < 0.05) in ZnGly and ZnPOS groups compared with the control. In addition, fur length and fur density increased (linear, P < 0.05) with Zn supplementation in the diet. In conclusion, our data show that dietary Zn addition improves growth performance by increasing nitrogen retention and fat digestibility in growing-furring mink and Z-POS is equally bioavailable to mink compared to ZnGly.

Effect of zinc concentration and source on performance, tissue mineral status, activity of superoxide dismutase enzyme and lipid peroxidation of meat in broiler chickens

The present experiment was conducted to investigate the effect of feeding different concentrations and the source of zinc (Zn) on the performance, tissue mineral status, superoxide dismutase (SOD) enzyme activity and meat quality in 0–4-week-old broiler chicks. Dietary treatments included the corn–soybean meal-based diet (control) and the basal diet supplemented with Zn at 20, 50 or 80 mg/kg, added as ZnSO4, Zn-methionine or Zn-enriched yeast. The results showed that birds fed Zn-supplemented diets had higher average weight gain and average feed intake than did birds fed the control diet (P < 0.01). At the end of the experiment, the Zn deposition in pancreas, liver and tibia increased (P < 0.01), regardless of the source, in response to increasing dietary Zn concentrations, whereas plasma Zn status was significantly increased by the highest Zn supplementation level. The main effect of Zn supplementation level was significant for the activities of Cu and/or Zn SOD in the liver and pancreas (P < 0.01). As broiler given 50 mg Zn had higher tissue SOD activity than did broilers fed the other treatment diets. Furthermore, Zn supplementation at up to 50 mg/kg significantly increased (P < 0.01) Zn accumulation and SOD activity and decreased lipid peroxidation in muscles around the femur bone. Results from the present study demonstrated that supplementation with 50 mg Zn may be sufficient for normal broiler growth to 28 days of age and the dietary inclusion of organic Zn could be utilised more effectively than that of inorganic sources.

Organic zinc absorption by the intestine of broilers in vivo

In Expt 1, a Zn-unsupplemented basal diet (control) and the basal diet supplemented with one of four different Zn sources, including ZnSO4, Zn-amino acid chelate with a weak chelation strength (Zn-AA W), Zn-protein chelate with a moderate chelation strength (Zn-Pro M) and Zn-protein chelate with a strong chelation strength (Zn-Pro S) were fed to broiler chickens from days 14 to 28. On day 28, Zn content in plasma from the hepatic portal vein increased (P0·05) and Zn-AA W(P<0·04) were higher than those for ZnSO4. These findings indicate that organic Zn absorption (especially Zn-Pro S) in intact living broilers was more effective than that of inorganic Zn; organic Zn absorption in the ligated duodenal segment was a saturable carrier-mediated process similar to that of ZnSO4. Moreover, except for MT, there might be other Zn transporters involved in Zn absorption that are affected by different Zn sources.

Effects of Dietary Zinc Pectin Oligosaccharides Chelate Supplementation on Growth Performance, Nutrient Digestibility and Tissue Zinc Concentrations of Broilers

The experiment was conducted to investigate the effects of zinc pectin oligosaccharides (Zn-POS) chelate on growth performance, nutrient digestibility, and tissue zinc concentrations of Arbor Acre broilers aged from 1 to 42 days. A total of 576 1-day-old broilers were randomly assigned into 4 groups with 9 replicates per group and 16 chicks per replicate. Chicks were fed either a basal diet (control) or basal diet supplemented with Zn-POS at 300 (Zn-POS-300), 600 (Zn-POS-600), or 900 mg/kg (Zn-POS-900), respectively, for 42 days. A 3-day metabolism trial was conducted during the last week of the experiment feeding. The average daily gain and the average daily feed intake of Zn-POS-600 were significantly higher (P < 0.05) than those of either the control, Zn-POS-300, or Zn-POS-900. Zn-POS-600 had the highest apparent digestibility of dry matter, crude protein, and metabolic energy among all groups. The control group had the lowest apparent digestibility of dry matter (P < 0.05), whereas the apparent digestibility of dry matter in Zn-POS-600 was higher (P < 0.05) than that of Zn-POS-300. The apparent digestibility of crude protein in Zn-POS-600 or Zn-POS-900 was higher (P < 0.05) compared to Zn-POS-300 or the control. The apparent digestibility of metabolic energy in Zn-POS-600 or Zn-POS-900 was higher (P < 0.05) than that of Zn-POS-300. Zn-POS-600 had the highest liver zinc concentrations (P < 0.05), while Zn-POS-900 had the highest pancreatic zinc concentrations (P < 0.05). Our data suggest that the supplementation of 600 mg/kg Zn-POS is optimal in improving the average daily gain and the average daily feed intake, utilization of dietary dry matter and crude protein, and increasing tissue zinc concentrations in liver and pancreas of broilers.

Effects of dietary zinc supplementation on nutrient digestibility, haematological biochemical parameters and production performance in male sika deer (Cervus nippon)

The purpose of the present study was to investigate the effects of dietary zinc (Zn) supplementation on antler growth, haematological biochemical parameters and nutrient digestibility in farmed male sika deer. Twenty-five 2-year-old growing male sika deer were randomly divided into five Groups (A, B, C, D and E; 5/group). Animals in Groups A, B, C, Dand E received 0, 5, 15, 40, 100 mg Zn/kg, respectively. Group A, without supplementation acted as a control. The treatment diets were the same basal diet supplemented with 5, 15, 40 and 100 mg Zn/kg (provided as Zn methionine), respectively. The results showed that the digestibility of dry matter (DM) and crude protein in Groups D and E were greater than that in Groups A, B and C (P < 0.05). Digestibility of neutral detergent fibre in Group E was higher than in the control group (P < 0.05). Plasma Zn concentrations were increased by Zn supplementation and were higher (P < 0.01) for the treatment groups supplemented with 15, 40 and 100 mg Zn/kg DM than for the control and 5 mg/kg Zn groups (P < 0.01). Faecal Zn content in Groups D and E was higher than that in Group A (P < 0.01). The content of albumin in plasma from Group E was greater than in the control and Groups B, C and D (P < 0.05). The concentrations of testosterone in plasma from Groups C, D and E were decreased (P < 0.05) compared with the control. The days between antler initiation and harvesting of deer in Groups D and E were decreased (P < 0.05). Average daily gain of fresh antler and dry antler of deer in Groups D and E was significantly higher than that in the control group (P < 0.05). In conclusion, a control diet containing 58.6 mg Zn/kg was inadequate for achieving optimal productivity for sika deer. The recommended Zn supplementation is from 76.7 to 99.0 mg/kg for 2-year-old male sika deer.

Effect of Zinc Source on Hematological, Metabolic Parameters and Mineral Balance in Lambs

This experiment was conducted to study the effects of different sources of zinc (Zn) on blood metabolites and balances of some minerals in lambs. In the first part, 20 6-7-month-old lambs were randomly allotted to four treatments including (1) basal diet containing 22.47 mg Zn/kg DM without supplementary Zn (control), (2) basal diet + 40 mg Zn/kg DM as ZnSO4 (ZnSO4 40), (3) basal diet + 20 mg Zn/kg DM as Zn-proteinate (Zn-Pro 20), and (4) basal diet + 40 mg Zn/kg DM as Zn-proteinate (Zn-Pro 40). Blood samples were taken on days 0, 28, and 65 before morning feeding. In the second part, four lambs from each treatment were randomly transferred to metabolic cages to evaluate the effects of different sources of Zn on N, Zn, Fe, and Cu retentions. This trial consisted of 18 days, with the first 12 days as the adaptation period followed by 6 days of sample collection. The results of this study showed that the source of Zinc had no significant effect on the analyzed parameters. Average daily gain and feed efficiency were improved by Zn supplementation (P < 0.05). Daily feed intake, plasma glucose, Fe and Cu concentrations, serum total antioxidant capacity, red blood cell count, packed cell volume, and hemoglobin concentration did not differ significantly between treatments (P > 0.05). Plasma Zn concentration, alkaline phosphatase (ALP) and bone-specific alkaline phosphatase (BALP) activity, and white blood cell and lymphocyte count differed significantly between control and Zn-supplemented groups (P < 0.05) as Zn supplementation improved these parameters. Nitrogen, Fe, and Cu retentions did not differ between treatments (P > 0.05). Zinc retention showed a significant difference between control and Zn-supplemented groups (P < 0.05), but there were no significant differences among the Zn-supplemented groups. The results of this study show that Zn supplementation improved performance and zinc retention in lambs. However, there were no significant differences between zinc sources used in this study.

Effect of copper- and zinc-methionine supplementation on bioavailability, mineral status and tissue concentrations of copper and zinc in ewes

The effect of feeding Cu- and Zn-methionine to ewes was studied in a 240d feeding trial. The plasma and tissue Cu and Zn concentrations and Cu/Zn-superoxide dismutase (Cu/Zn-SOD) activity were employed to assess the relative bioavailability from Cu- and Zn-methionine. The macro and micronutrient intake, utilization, plasma mineral status, tissue accumulation of Cu and Zn as well as wool concentration of Cu and Zn were studied in ewes (n=12) fed a corn-soybean meal based basal diet with 50% more Cu and Zn supplementation over the basal diet either from Cu- and Zn-sulfate (Cu-Sulf+Zn-Sulf group) or Cu- and Zn-methionine (Cu-Meth+Zn-Meth group). The average daily feed intake and body weight gain of ewes did not differ due to dietary supplementation of Cu- and Zn-methionine. However, dry matter intake was comparatively lower and thus resulted in better feed: gain in Cu- and Zn-methionine group as compared to ewes fed Cu- and Zn-sulfate. Supplementation of Cu and Zn over the basal diet either from methionine-chelated or sulfate sources resulted in increased plasma Cu and Zn as well as Cu/Zn-SOD activity on d-30, which indicated a positive correlation between plasma Cu and Zn and Cu/Zn-SOD activity. The gut absorption, liver concentrations of Cu and Zn, and liver Cu/Zn-SOD activity were significantly (P<0.01) higher in ewes supplemented with Cu- and Zn-methionine compared to Cu- and Zn-sulfate. Periodical analysis of wool samples indicated no significant difference in Cu and Zn content between Cu-and Zn-methionine and Cu- and Zn-sulfate groups. Feeding of Cu and Zn from methionine-chelated source resulted in reduced (P<0.01) excretion of Cu and Zn in feces indicating their better utilization, and this will have positive implication on environment. The gut absorption values, plasma and liver tissue concentrations of Cu and Zn supported the hypothesis that Cu- and Zn-methionine supplements have better bioavailability compared to Cu- and Zn-sulfate and Cu- and Zn-dependent enzyme (Cu/Zn-SOD) could be used to determine the bioavailability of Cu and Zn.

The influence of supplementation of different forms of zinc in goats on the zinc concentration in blood plasma and milk

The aim of the experiment was to study zinc concentration in goat's milk during a short-term oral supplementation of three organic and one inorganic form of zinc and the influence of Zn supplementation on the concentration of Zn and Cu in blood plasma. The experiment involved 31 lactating goats. The group C was the control, group L received zinc lactate, group A received zinc chelate, group T received amino acid-polypeptidic complex with zinc, and group O received zinc oxide. Zinc preparations were administered orally in 500 mg Zn per animal for 28 days. In the course of the experiment, Zn concentration in plasma increased significantly in all experimental groups and in the control group was unchanged. The concentration of zinc in milk during the experiment fluctuated in individual groups, but there were no significant differences between groups. After 28 days of Zn supplementation, Zn concentration in milk of goats was similar as at the start of the experiment in all groups. According to our results, the supplementation of different forms of zinc did not influence the concentration of Zn in milk, but significantly influenced the Zn concentration in blood plasma. The efficiency of different organic and inorganic forms of zinc was similar.

Zinc-responsive dermatosis in goats suggestive of hereditary malabsorption: two field cases

Two cases of zinc deficiency in dairy goats from different flocks and not associated with a zinc-deficient diet are described. Hard, dry, hyperkeratotic skin, hair loss and pruritus especially prominent on the back, legs, udder, face and ears were the most common clinical signs. Skin biopsy findings revealed a mixture of orthokeratotic and parakeratotic hyperkeratosis. On initial examination, serum zinc concentrations were low in both goats (461 microg L(-1) and 521 microg L(-1), respectively). Although mild skin lesions persisted during the early stages of zinc supplementation, skin lesions completely resolved after prolonged oral zinc supplementation. Withdrawal of zinc supplementation resulted in re-appearance of lesions in both animals. Case 2 gave birth to two kids, one of which showed mild skin lesions at 8 months of age together with a low serum zinc concentration (434 microg L(-1)), suggestive of hereditary zinc malabsorption. The other kid remained free of skin lesions and had a serum zinc concentration (530 microg L(-1)) within the normal range. On the basis of historical and clinical findings, the cases presented here more closely resemble Syndrome 1 hereditary zinc deficiency as seen in Nordic dog breeds rather than other zinc deficiency conditions seen in other species. It is suggested that zinc deficiency in these goats was due to hereditary malabsorption of dietary zinc. This is the first descriptive study of this condition in goats. Life-long zinc supplementation may be necessary in such patients.

Effect of Zinc Source and Dietary Level on Zinc Metabolism in Holstein Calves

Forty-eight Holstein male calves were stratified by origin and body weight and randomly assigned to one of 4 treatment groups. Dietary treatments were administered in 2 phases. In phase 1, treatment groups received the basal diet with no supplemental Zn (control), basal diet plus 20 mg of Zn/kg of DM as ZnSO4 or Zn proteinate (ZnProt), or basal diet plus 20 mg of Zn/kg of DM with 50% of the Zn supplied from each source (ZnM) for 98 d. In phase 2, calves continued to receive the same Zn source fed in phase 1; however, half of the calves in each treatment group were randomly selected to receive 500 mg of Zn/kg of DM (HiZnSO4, HiZnProt, HiZnM) for 14 d. Gain, feed intake, and feed efficiency of calves were not affected by treatment in either phase of the experiment. Treatment had no affect on plasma Zn concentration or alkaline phosphatase activity in phase 1, but liver Zn concentration was greater in calves fed ZnSO4 than those fed ZnProt. In phase 2, plasma Zn was greater in calves fed HiZnProt and HiZnM than in those fed HiZnSO4. Liver Zn was greater in calves fed HiZnProt than in those fed HiZnSO4. Duodenal Zn concentrations were greater in calves supplemented with HiZnProt and HiZnM than those supplemented with HiZnSO4. Liver metallothionein was greater in calves that received 500 mg of Zn/kg than in calves that received 20 mg of Zn/ kg, but was not affected by Zn source. Calves fed HiZnProt and HiZnM had greater kidney Zn concentrations than those fed HiZnSO4. Heart, spleen, testicular, and bone Zn concentrations were not affected by Zn source. Hoof wall samples contained nearly 3-fold greater Zn concentrations than hoof sole. Calves fed ZnSO4 had greater Zn concentration in hoof wall samples than those fed ZnM. Hoof sole Zn concentration was not affected by Zn source or concentration. Plasma and tissue Zn concentrations at harvest were generally similar in calves supplemented with 20 mg of Zn/kg from ZnSO4 or ZnProt. However, when supplemented at 500 mg of Zn/kg, ZnProt was absorbed to a greater extent than ZnSO4, based on higher plasma, liver, duodenal, and kidney Zn concentrations.

Trace mineral bioavailability in ruminants

Absorption of selenium and copper is much lower in ruminants than in nonruminants. The low absorption of these minerals in ruminants is due to modifications that occur in the rumen environment. Selenium bioavailability is reduced by high dietary sulfur and the presence of cyanogenetic glycosides in certain legumes. Feeding organic selenium from selenomethionine or selenized yeast results in much higher tissue and milk selenium concentrations than are obtained with selenite. High dietary molybdenum in combination with moderate to high dietary sulfur results in formation of thiomolybdates in the rumen. Thiomolybdates greatly reduce copper absorption, and certain thiomolybdate species can be absorbed and interfere systemically with copper metabolism. Independent of molybdenum, high dietary sulfur reduces copper absorption perhaps via formation of copper sulfide. High dietary iron also reduces copper bioavailability. Dietary factors that affect bioavailability of zinc in ruminants are not well defined. Phytate does not affect zinc absorption in ruminants because microbial phytase in the rumen degrades phytate. Manganese is very poorly absorbed in ruminants, and limited research suggests that high dietary calcium and phosphorus may reduce manganese absorption.

Regional distribution and localization of zinc and metallothionein in the intestine of rats fed diets differing in zinc content

BACKGROUND

Zinc (Zn) is protective and enhances epithelial repair in gut diseases. In this study we investigate the localization and distribution of Zn and its binding protein, metallothionein (MT), in the gut of rats fed diets varying in Zn content.

METHODS

Male-Sprague Dawley rats were fed low, normal, high, or excess Zn in their diets (10, 100, 400, or 1000 mg Zn/kg, respectively) and killed 7 days later. Blood, liver, and gut tissues were collected. Tissue Zn was determined with atomic absorption spectrophotometery and MT with a Cd/haem affinity assay. Zn and MT were immunohistochemically localized in the small-intestinal wall with zinquin and an anti-MT antibody.

RESULTS

Most Zn in the intestinal wall was present in the mucosal scrapings, with 94% membrane-bound and 6% cytosolic, irrespective of dietary Zn. MT levels increased in all gut regions at dietary Zn levels above 100 mg Zn/kg. MT was 40% higher in the ileum than in other gut regions in rats fed low- and normal-Zn diets. The Zn content of the ileum was also 20% higher than that of other gut regions in rats fed low-, normal-, or high-Zn diets. Zn and MT were colocalized in the base of the intestinal crypts, most visibly in the ileum.

CONCLUSION

Mucosal cytosolic Zn and MT concentrations are increased only at high or excessive Zn intakes in all gut regions except the ileum, which can respond to a lower Zn intake. As the cytosolic Zn pool most likely influences mucosal protection and repair mechanisms, it is proposed that an increased MT may indicate the adequacy of oral Zn therapy in gut disease.

Equivalent uptake of organic and inorganic zinc by monkey kidney fibroblasts, human intestinal epithelial cells, or perfused mouse intestine

Zinc (Zn) is recognized as an essential nutrient, and is added as a supplement to animal and human diets. There are claims that zinc methionine (ZnMet) forms a stable complex that is preferentially transported into tissues, and this has contributed to uncertainty about conflicting reports on the bioavailability of various Zn compounds. This study evaluated the cellular and intestinal uptake of inorganic and organic forms of Zn. Steady-state uptake of 65Zn by human intestine epithelial cells, and monkey kidney fibroblasts was not significantly different with zinc chloride (ZnCl2), ZnMet, or zinc propionate (ZnProp) (P > 0.05). Uptake of 65Zn from zinc chelated with EDTA was significantly lower (P < 0.01). In live mice, 65Zn uptake by perfused intestine and deposition in intestine and liver showed no significant difference between ZnCl2 and ZnMet. Equimolar [65Zn]methionine and zinc[35S]methionine were prepared according to a patented method that yields "complexed" Zn. Cellular uptake of the radiolabeled methionine was <0.1% of the radiolabeled Zn from these complexes, indicating separate uptake of the Zn and methionine. Gel filtration did not distinguish between 65Zn in ZnCl2, ZnProp, or reagent ZnMet, though feed-grade ZnMet containing >10% protein did give a higher-mol-wt form of 65Zn. Results of this study show equivalent uptake of Zn from inorganic and organic compounds, and support recent feed trials on Zn bioavailability.

Zinc oxide and amino acids as sources of dietary zinc for calves: effects on uptake and immunity

Calf starter diets were formulated to contain 60 ppm of Zn, 150 or 300 ppm of Zn in the form of Zn-Met and Zn-Lys, or 300 ppm of Zn in the form of ZnO to compare relative bioavailability and effects on immunity. Holstein heifer calves were weaned at wk 5 and fed experimental starter diets from wk 6 to 12. Feed intake, body weight, Zn concentrations in liver and serum fractions, and mineral concentrations in serum were measured to determine the effects of treatment. In addition, peripheral blood lymphocyte blastogenesis, interleukin-2 production, cytotoxic activity, and the ability of blood neutrophils to phagocytose and kill bacteria were assessed at wk 0, 2, 4, and 6 of the trial. Feed intakes and body weight gains were similar among calves. Concentrations of Zn in serum were elevated in calves fed 300 ppm of Zn as Zn-Met and Zn-Lys but not in calves fed ZnO. Concentrations of Zn in liver were significantly elevated by 300 ppm of Zn in the form of Zn-Met and Zn-Lys (360 micrograms/g) but not by the other Zn treatments or by the control (245 micrograms/g). No treatment had an effect on the concentrations of Lys and Met in serum; however, concentrations of Lys did decrease in serum as the age of the calves increased. There was no significant treatment effect on mitogen-induced lymphocyte blastogenesis, interleukin-2 production, lymphocyte cytotoxicity, or phagocytic and intracellular killing ability of blood neutrophils. These data indicated greater absorption and retention of Zn when administered in the form of Zn-Met and Zn-Lys than that when ZnO was administered to young calves. However, there was no advantage to the immune function of extra dietary Zn.