Zn Amino Acid Research Articles

Characterization of zinc amino acid complexes for zinc delivery in vitro using Caco-2 cells and enterocytes from hiPSC

Zn is essential for growth and development. The bioavailability of Zn is affected by several factors such as other food components. It is therefore of interest, to understand uptake mechanisms of Zn delivering compounds to identify ways to bypass the inhibitory effects of these factors. Here, we studied the effect of Zn amino acid conjugates (ZnAAs) on the bioavailabilty of Zn. We used Caco-2 cells and enterocytes differentiated from human induced pluripotent stem cells from a control and Acrodermatitis enteropathica (AE) patient, and performed fluorescence based assays, protein biochemistry and atomic absorption spectrometry to characterize cellular uptake and absorption of ZnAAs. The results show that ZnAAs are taken up by AA transporters, leading to an intracellular enrichment of Zn mostly uninhibited by Zn uptake antagonists. Enterocytes from AE patients were unable to gain significant Zn through exposure to ZnCl2 but did not show differences with respect to ZnAAs. We conclude that ZnAAs may possess an advantage over classical Zn supplements such as Zn salts, as they may be able to increase bioavailability of Zn, and may be more efficient in patients with AE.

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.

The influence of supplemental Zn-amino acid complex and ractopamine hydrochloride feeding duration on growth performance and carcass characteristics of finishing beef cattle.

Previous research indicates that finishing steer ADG and G:F increases linearly with increasing dietary Zn-amino acid complex (ZnAA) supplementation in cattle fed ractopamine hydrochloride (RAC). The objective of this study was to determine the influence of supplemental Zn-amino acid complex on growth performance and carcass characteristics of finishing steers fed RAC for 0, 28, or 42 d prior to harvest. This study was organized as 2 groups (GRP) of steers fed concurrently, for 91 (GRP 1) or 84 d (GRP 2). A total of 324 steers (463 ± 23.4 kg) were fed a corn-based finishing diet supplemented with 60 mg Zn/kg diet DM (as ZnSO). Steers were blocked by weight to pens of 6 steers, and assigned to receive either 0 (CON) or 60 mg supplemental Zn/kg DM from ZnAA ( = 27 pens per treatment). Receiving ZnAA for 49 (GRP 1) or 42 d (GRP 2) prior to start of RAC feeding had no impact on growth of steers ≥ 0.19). Forty-two d prior to harvest, pens were equally assigned within CON or ZnAA treatments to receive RAC at 300 mg∙steer∙d for 0 (NoRAC), 28 (28RAC), or 42 d (42RAC) prior to harvest, creating 6 final treatments ( = 9 pens per treatment). All steers within a GRP were harvested on the same day. Pen was the experimental unit, and the statistical model included the fixed effects of ZnAA, RAC, and block nested within GRP, and the random effect of pen. Ractopamine hydrochloride supplementation increased carcass-adjusted ADG, final BW, HCW, and ribeye area ( ≤ 0.007). There was an effect of ZnAA within 28RAC and 42RAC where carcass-adjusted ADG ( ≤ 0.10), and final BW and HCW ( ≤ 0.05) were greater in ZnAA supplemented vs. CON steers, and 28RAC steers supplemented with ZnAA had improved overall carcass-adjusted G:F relative to CON steers ( = 0.04). However, when steers did not receive RAC there was no effect of ZnAA on final BW, ADG, or HCW ( ≥ 0.78). Additionally, ZnAA supplementation had no effect on the difference in performance between steers supplemented with RAC for 28 vs. 42 d ( 0.21). In conclusion, under the conditions of this study supplemental ZnAA did not prevent the diminished response to RAC as days on RAC increased from 28 to 42. However, there appears to be a synergistic effect of ZnAA on RAC-induced cattle growth, as supplementing 60 mg Zn/kg DM from ZnAA to cattle fed RAC improved overall growth and HCW.

The effects of zinc hydroxychloride and basic copper chloride on growth performance, carcass characteristics, and liver zinc and copper status at slaughter in yearling feedlot steers

ABSTRACT Several trace mineral sources are available for use in feedlot diets. This study was conducted to provide nutritionists with information supporting the formulation of more cost effective trace mineral supplementation programs. Crossbred yearling steers (n = 288, initial BW = 319 ± 10.2 kg), housed in 32 pens (8 pens per treatment), were used in a randomized complete block design experiment to compare the effects of Zn hydroxychloride and basic Cu chloride, fed at 2 concentrations, to Zn and Cu sulfate or Zn and Cu sulfate plus Zn and Cu amino acid complexes on feedlot performance, carcass merit, and liver mineral status at slaughter. Treatments (100% DM basis) included 90 mg/kg of Zn from Zn sulfate and 15 mg/kg of Cu from Cu sulfate; 67.5 mg/kg of Zn from Zn sulfate plus 22.5 mg/kg of Zn from Zn amino acid complex (Availa Zn; Zinpro Corporation, Eden Prairie, MN) and 11.25 mg/kg of Cu from Cu sulfate plus 3.75 mg/kg of Cu from Cu amino acid complex (Availa Cu; Zinpro Corporation); 90 mg/kg of Zn from Zn hydroxychloride (IntelliBond Z; Micronutrients, Indianapolis, IN) and 15 mg/kg of Cu from basic Cu chloride (IntelliBond C; Micronutrients); and 54 mg/kg of Zn from Zn hydroxychloride and 9 mg/kg of Cu from basic Cu chloride. No significant (P > 0.10) treatment differences were found for initial, d-28, or final BW. Average daily gain, DMI, G:F, NE recovery, carcass characteristics, and liver Cu and Zn concentrations at the time of slaughter did not differ (P > 0.10) among treatments. These results indicate that Zn hydroxychloride and basic Cu chloride were effectively absorbed and used by yearling steers and can be fed at a reduced rate compared with current industry feeding practices without negative effects on feedlot performance, carcass merit, and liver Zn and Cu status.

Zinc and iron concentrations in grain milling fractions through combined foliar applications of Zn and macronutrients

Agronomic biofortification of wheat with Zn and Fe can correct micronutrient deficiency in humans who consume wheat. In this study, two field experiments were conducted to investigate the effects of foliar Zn application combined with (1) macronutrients and Zn-amino acid chelates and (2) different soil N levels on Zn and Fe concentrations in whole grain and flour grown with straw incorporation. The results of the first experiment showed that flour Zn concentrations increased by 60.5%, 39.9%, and 56.2% due to the foliar application of ZnSO4 combined with N (urea), PK (KH2PO4), and K (K2SO4), respectively, compared to the control, and the corresponding increases in whole grain were 65.6%, 38.1%, and 50.1%, respectively. Compared with foliar Zn application alone, foliar N and K applications caused similar increases in grain Zn and Fe concentrations, whereas the foliar application of Zn combined with PK resulted in a significant decrease (approximately 12.1% across the two cropping years) in whole-grain Zn concentrations. Flour Zn concentrations, however, were unaffected by foliar Zn combined with PK fertilization and significantly increased due to the foliar application of Zn combined with N or K (in the first cropping year) compared to foliar Zn application alone. Foliar Zn combined with macronutrient fertilization tended to increase flour and grain Fe concentrations. Additionally, reducing the soil N application rate generally had a small effect on flour and grain Zn and Fe concentrations. The results of the second experiment showed that the application of Zn(Gly)2, alone or in combination with N(urea), caused similar increases in Zn and Fe concentrations in flour and whole grain. Foliar ZnSO4 combined with macronutrient fertilization under 15% reduced soil N supply and straw incorporation is an economical, effective, practical, and environmentally friendly agronomic practice for enhancing Zn and Fe concentrations in flour.

No indications that zinc and protein source affect Zn bioavailability in sows during late gestation fed adequate dietary Zn concentrations

Previous in vitro research has shown the possibility of spontaneous chelation of Zn in the presence of easily digestible protein sources. The objective of this study was to investigate the possible interaction between zinc (Zn) source and protein source on the in vivo Zn bioavailability in sows during late gestation that were fed adequate dietary Zn concentrations. Fifty-six sows were randomly allocated to one of four dietary treatment groups during a 20-day experimental period: (1) organic Zn+soybean meal, (2) inorganic Zn+soybean meal, (3) organic Zn+hydrolysed feather meal, and (4) inorganic Zn+hydrolysed feather meal. Zinc was provided at adequate dietary Zn concentrations, in which organic Zn was added as a Zn amino acid complex and inorganic Zn as ZnO. Blood samples were collected at the start (day 1) and at the end (day 20A) of the experimental period before feeding and 3h after feeding (day 20B) to determine plasma Zn and serum metallothionein (MT) concentration. Faecal samples were collected rectally, alternately in the morning (day 15, 17, and 19) and afternoon (day 16, 18, and 20) directly after feeding to calculate apparent nutrient digestibility and apparent Zn absorption. Neither Zn nor protein source affected Zn status (plasma Zn: P=0.288 and P=0.237, respectively, Serum MT: P=0.161 and P=0.193, respectively) or apparent Zn absorption (P=0.360 and P=0.527, respectively). Hydrolysed feather meal showed lower crude protein, crude fat, and crude ash digestibility compared to soybean meal (P<0.001). Faecal Zn concentration was not affected by Zn source (P=0.442). This study did not confirm the earlier observed in vitro effect of protein source on Zn bioavailability and shows that, at adequate levels commonly used in practice, the choice of Zn or protein source does not influence Zn status.

Effects of supplemental zinc source and level on antioxidant ability and fat metabolism-related enzymes of broilers

The objective of the present study was to investigate the effects of dietary supplemental Zinc (Zn) source and level on antioxidant ability and fat metabolism-related enzymes of broilers. Dietary treatments included the Zn-unsupplemented corn-soybean meal basal diet (control) and basal diets supplemented with 60, 120, or 180 mg Zn/kg as Zn sulfate, Zn amino acid chelate with a weak chelation strength of 6.5 quotient of formation (Qf) (11.93% Zn) (Zn-AA W), Zn proteinate with a moderate chelation strength of 30.7 Qf (13.27% Zn) (Zn-Pro M), or Zn proteinate with an extremely strong chelation strength of 944.0 Qf (18.61% Zn) (Zn-Pro S). The results showed that dietary supplemental Zn increased (P < 0.01) Zn contents in the liver, breast, and thigh muscles of broilers, and up-regulated mRNA expressions of copper and Zn containing superoxide dismutase (CuZnSOD) and metallothioneins (MT) in the liver (P < 0.01) and thigh muscle (P < 0.05), and also enhanced (P < 0.05) CuZnSOD activities in the breast and thigh muscles, which exerted antioxidant ability and a decreased malondialdehyde (MDA) level in the liver (P < 0.01) and breast and thigh muscles (P < 0.05) of broilers. Furthermore, supplemental Zn increased activities of malate dehydrogenase (MDH) and lipoprotein lipase (LPL) in the abdominal fat (P < 0.05), and fatty acid synthetase (FAS) and LPL in the liver (P < 0.01), which were accompanied with up-regulation (P < 0.01) of the mRNA expressions levels of these enzymes in the abdominal fat and liver of broilers. Dietary Zn source, and an interaction between Zn source and level, had no effects on any measurements. It is concluded that dietary Zn supplementation improved Zn status and resulted in promoting antioxidant ability and activities and gene expressions of fat metabolism-related enzymes of broilers regardless of Zn source and level, and the addition of 60 mg Zn/kg to the corn-soybean meal basal diet (a total dietary Zn of approximately 90 mg/kg) was appropriate for improving the above aspects of broilers.

Comparison of chelated zinc and zinc sulfate as zinc sources for growth and immune response of shrimp (Litopenaeus vannamei)

Zinc methionine (ZnMet), zinc lysine (ZnLys), zinc glycine (ZnGly) and zinc sulfate (ZnSO4·H2O) were evaluated as dietary zinc sources for Litopenaeus vannamei. Three Zn–amino acid complexes with a molar amino acid to Zn ratio of 2:1 were compared to Zn sulfate using a casein-based purified diet. Five groups with four replicates of shrimps (mean weight 0.72±0.02g) were given a basal diet either unsupplemented (control) or supplemented with 30mgZnkg−1 sulfate (ZnSO4·H2O) or the organic sources respectively, for 12weeks. Results showed that the source of Zn affects shrimp growth, survival and immune parameters. Shrimp fed diets with organic zinc supplementation produced significantly higher growth, survival and immune parameters than ZnSO4 treatment. Shrimp supplemented with ZnMet had the highest weight gain and immune parameters. However, there were no significant differences in weight gain, survival, total hemocyte counts, phagocytotic activity, PO, AKP and SOD between the ZnLys and ZnGly groups. Results suggest that Zn from ZnMet was a better source than the other zinc forms.

Zinc–amino acid complexes are more stable than free amino acids in saline and washed soils

Biodegradability of metal–amino acids (AA) complexes has remained undocumented. Such knowledge is necessary to assess role of AA in metal mobility and bioavailability in the soil environments. In this study, biodegradation of free glycine (Gly), glutamine (Gln), arginine (Arg) and histidine (His) was compared with their Zn complexes in a natural saline soil before and after washing. The soil samples were collected from 0 to 15 cm depth of a saline soil before and 7 days after washing. The heavy washing of the saline soils using low salinity irrigation water (EC < 2 dS m−1) is a common practice applied by the farmers in the region before plant seeding. Mineralization of AA, revealed by CO2 release (35–66% in saline soil and 20–42% in washed soil) after 48 h incubation indicating rapid degradation of AA in soil. Complexation with Zn significantly reduced mineralization of AA. In saline soil treated with AA, the cumulative release of CO2 after 48 h incubation varied from 12.4 to 47.5 mg C kg−1, while it was 5.8–37.9 mg C kg−1 in the same soil treated with Zn–AA complexes (ZnAAC). The effect of complexation with Zn on CO2 release was dependent on AA type. Lower C mineralization and thus, higher stability of ZnAAC compared with free AA supports a conclusion that complexation of metal greatly decreases degradability of AA. According to the results, the effectiveness of complexation with proteinaceous AA in metal mobilization in soil has to be given greater consideration than that reported previously.

The effectiveness of foliar applications of synthesized zinc-amino acid chelates in comparison with zinc sulfate to increase yield and grain nutritional quality of wheat

The effectiveness of foliar spray of certain Zn-amino acid chelates (ZnAAC) including Zn-arginine [Zn(Arg)2], Zn-glycine [Zn(Gly)2] and Zn-histidine [Zn(His)2] on the yield and grain quality of two different Zn-deficiency tolerant wheat cultivars (Triticum aestivum cvs. ‘Back Cross’ and ‘Kavir’) was investigated under field conditions. Foliar application of Zn, regardless of the used source, significantly improved grain yield of both wheat cultivars with a mean increase of 15.2% for the first year and 19.2% for the second year. Grain Zn, iron (Fe) and protein concentrations were on average 14.3% higher in wheat plants sprayed with ZnAAC than those sprayed with ZnSO4. Very significant positive correlation between grain Zn, Fe, and protein concentrations indicates that the genes affecting the grain accumulations of Zn, Fe and protein are probably closely linked. Foliar application of Zn fertilizers resulted in significant decrease (on average 17.9%) of grain phytic acid (PA) and PA:Zn molar ratio (on average 16.3%) in comparison with the control treatment although the magnitude of this reduction was greater for ZnAAC than ZnSO4. According to the results obtained in this study, the ZnAAC should be considered as new Zn fertilizer sources for improving yield and total and bioavailable Zn concentrations of wheat grain.

Relative bioavailabilities of organic zinc sources with different chelation strengths for broilers fed diets with low or high phytate content

A six-day experiment was conducted to estimate the relative bioavailability values (RBV) of zinc (Zn) in three organic sources (oZn) with different chelation strengths compared to inorganic ZnSO4 (iZn) for broilers fed a low or high phytate diet. A total of 1080, one-d-old male broiler chicks were randomly assigned to one of 18 dietary treatments (six replicates cages of ten chicks per cage) in a completely randomized design involving a 2×2×4 factorial arrangement with two levels of added phytate (0 or 10g phytate as sodium phytate/kg), two levels of added Zn (30 or 60mg/kg) and four Zn sources (iZn and three oZn sources) plus one low and one high phytate control treatments without Zn addition. The three oZn sources consisted of (1) Zn amino acid with weak chelation strength (ZnAA-L, formation quotient Qf=6.6, containing 119g Zn/kg), (2) Zn proteinate with moderate chelation strength (ZnPRO-M, Qf=30.7, containing 133g Zn/kg) or (3) Zn proteinate with strong chelation strength (ZnPRO-H, Qf=944.0, containing 186g Zn/kg). Chicks were harvested at 6 days of age and pancreas metallothionein (MT) mRNA expression was used to estimate Zn RBV. Pancreas MT mRNA expression increased (P<0.01) as dietary Zn level increased. Chicks fed high phytate diets had lower (P<0.05) MT mRNA expression than chicks fed low phytate diets. Based on multiple linear regression slope ratios with ZnSO4 set at 1.00, the RBV of ZnAA-L, ZnPRO-M and ZnPRO-H were 1.01, 1.28 and 0.70, respectively, for low phytate diets, and 1.05, 1.39 and 0.92, respectively, for high phytate diets. The slope for the oZn source with moderate chelation strength differed (P<0.05) from iZn and the other two oZn sources. The RBV of ZnAA-L, ZnPRO-M and ZnPRO-H under the high phytate diet increased by 0.04, 0.11 and 0.22, respectively, compared to those under the low phytate diet. Results indicate that the oZn sources with moderate or strong chelation strength offer partial or complete resistance to interference from high dietary phytate during digestion; and the oZn with moderate chelation strength had a greater RBV with both low and high phytate diets than iZn or oZn sources with weak or strong chelation strength.

Biofortification and Bioavailability of Rice Grain Zinc as Affected by Different Forms of Foliar Zinc Fertilization

BackgroundZinc (Zn) biofortification through foliar Zn application is an attractive strategy to reduce human Zn deficiency. However, little is known about the biofortification efficiency and bioavailability of rice grain from different forms of foliar Zn fertilizers.Methodology/Principal FindingsFour different Zn forms were applied as a foliar treatment among three rice cultivars under field trial. Zinc bioavailability was assessed by in vitro digestion/Caco-2 cell model. Foliar Zn fertilization was an effective agronomic practice to promote grain Zn concentration and Zn bioavailability among three rice cultivars, especially, in case of Zn-amino acid and ZnSO4. On average, Zn-amino acid and ZnSO4 increased Zn concentration in polished rice up to 24.04% and 22.47%, respectively. On average, Zn-amino acid and ZnSO4 increased Zn bioavailability in polished rice up to 68.37% and 64.43%, respectively. The effectiveness of foliar applied Zn-amino acid and ZnSO4 were higher than Zn-EDTA and Zn-Citrate on improvement of Zn concentration, and reduction of phytic acid, as a results higher accumulation of bioavailable Zn in polished rice. Moreover, foliar Zn application could maintain grain yield, the protein and minerals (Fe and Ca) quality of the polished rice.ConclusionsFoliar application of Zn in rice offers a practical and useful approach to improve bioavailable Zn in polished rice. According to current study, Zn-amino acid and ZnSO4 are recommended as excellent foliar Zn forms to ongoing agronomic biofortification.

Effects of supplemental zinc source and level on growth performance, carcass traits, and meat quality of broilers

The objective of this study was to investigate the effects of dietary supplemental Zn on growth performance, carcass traits, and meat quality of broilers. Dietary treatments included the corn-soybean meal-based diet (control) and the basal diet supplemented with 60, 120, or 180 mg of Zn/kg as ZnSO(4), Zn amino acid A, Zn proteinate B, or Zn proteinate A. The results showed that birds fed diets supplemented with Zn had higher ADFI, ADG, and percentage of eviscerated yield than birds fed the control diet. Supplemental Zn significantly increased the redness value in breast muscle and pH values in thigh muscle, decreased shear force in thigh muscle, and decreased drip loss in breast and thigh muscle. The DM and intramuscular fat contents of the breast muscle in broilers fed diets with supplemental Zn were higher than those of the control. Results from this study indicated that Zn could promote growth and improve production performance of broilers independent of Zn source.

Effects of zinc source and phytate on zinc absorption by in situ ligated intestinal loops of broilers

Two experiments were conducted to investigate the effects of Zn source and phytate on Zn absorption in broilers. In experiment 1, eight different Zn sources, including ZnSO4, Zn Gly chelate, Zn Met chelate, and Zn amino acid C complex with the weak complex strength (Zn AA C), Zn protein B complex with the moderate complex strength (Zn Pro B), and zinc protein A complex with the strong complex strength (Zn Pro A), and the mixtures of ZnSO4 with either Gly or Met (Zn+Gly or Zn+Met, respectively) were used to study the effects of Zn sources on Zn absorption by in situ ligated intestinal loops of broilers. In experiment 2, 3×4 factorial arrangements of treatments involving 3 phytate levels and 4 Zn sources were used to investigate the effect of phytate on Zn absorption. Three molar ratios of phytate to Zn were 0, 2:1, and 10:1, respectively, and 4 Zn sources included ZnSO4, Zn AA C, Zn Pro B, and Zn Pro A, respectively. No differences (P>0.05) were found among the absorption percentages of Zn as Zn+Gly, Zn+Met, and ZnSO4 in 3 intestinal segments. The absorption percentages of Zn as Zn Gly chelate, Zn Met chelate, Zn AA C, Zn Pro B, and Zn Pro A in the duodenum and jejunum were 29 to 129% higher (P<0.05) than those of Zn as ZnSO4, Zn+Gly, and Zn+Met in the following order: Zn Pro A>Zn Pro B>Zn AA C>Zn Gly chelate or Zn Met chelate>ZnSO4, Zn+Met, or Zn+Gly. The changes of Zn absorption as different Zn sources in the ileum were also observed and were similar to those in the duodenum and jejunum. There was a significant interaction (P<0.05) between phytate levels and Zn sources on Zn absorption in 3 intestinal segments. The absorption percentage of Zn as ZnSO4 in the duodenum with a phytate-added group (10:1) was 40% (P<0.05) lower than that of Zn as ZnSO4 without a phytate-added group. With the increasing phytate levels, the changes of Zn absorption as organic Zn sources in 3 intestinal segments were similar to those of ZnSO4 in the duodenum. However, the reduction of Zn absorption as organic Zn sources was lessened with the increasing complex strengths, and the highest absorption of Zn as Zn Pro A was observed. These results indicated that the absorption of Zn as organic Zn was more effective than that of Zn as inorganic Zn. The organic Zn absorption increased with the increasing complex strengths as well. The simple mixture of ZnSO4 with amino acid did not increase Zn absorption. In addition, the phytate could reduce Zn absorption as different Zn sources in 3 intestinal segments. Organic Zn sources could lessen the negative effect of phytate on Zn absorption, and then the absorption of organic Zn, especially Zn Pro A with strong complex strength, was more effective than inorganic Zn under the high levels of phytate.

Influence of Soil Type on the Mobility and Bioavailability of Chelated Zinc

The objective of this study was to compare the distribution, mobility, and relative effectiveness of Zn from Zn-amino acids (Zn-AA) and Zn-DTPA-HEDTA-EDTA (Zn-CH) (DTPA, diethylenetriaminepentaacetate; HEDTA, N-2-hydroxyethyl-ethylenedinitrilotriacetate; and EDTA, ethylenedinitrilotetraacetate) sources by applying different Zn levels to weakly acidic and neutral soils in laboratory (incubation and soil column studies) and greenhouse conditions. The experiments were carried out for 60 days in incubation and column experiments and for 45 days in a greenhouse experiment. The zinc soil behavior was evaluated by DTPA-TEA and Mehlich-3 extractions and sequential speciation. The incubation experiment showed that the highest concentrations of available Zn in weakly acidic soil occurred with Zn-AA treatments, whereas in the neutral soil Zn-CH treatments produced the highest quantities of available Zn. The column experiment showed that in neutral soil, with slow to moderate permeability in the Ap and Bt horizons, only Zn-CH significantly increased the mobility of Zn through the column with respect to the control and the Zn-AA source: 31% of the Zn applied as synthetic chelate was leached from the column. The greenhouse experiment showed that, at different rates of Zn application, the Zn carriers increased Zn uptake by maize (Zea mays L.). The use of applied Zn by maize, or Zn utilization, was greatest when the Zn treatments were Zn-CH (3.3%) at 20 mg kg-1 and Zn-CH (4.9%) at 10 mg kg-1, in weakly acidic and neutral soils, respectively.

Responses of broilers to dietary zinc concentrations and sources in relation to environmental implications

1. Since high concentrations of zinc are associated with reduced crop yields, environmental concerns are emerging regarding zinc accumulation in areas where poultry production is prevalent. This study investigates growth performance and zinc utilisation during the life cycle of broilers when diets were supplemented with various concentrations of zinc from two different sources. 2. A total of 740 Cobb 500 1-d-old male broiler chicks was randomly distributed into 88 battery cages. Excreta were collected over a 48-h period on d 10, 17, 24, 31, 38, and 45 to measure zinc excretion on a dry matter basis. 3. During the 45-d experimental period, broilers were given a maize–soybean meal basal diet (30 mg/kg zinc) supplemented with 0, 20, 40, and 80 mg/kg of zinc from zinc sulphate, Availa®Zn amino acid complex, or an equal combination of zinc sulphate and Availa®Zn amino acid complex. 4. Progressive additions of zinc to the basal diet significantly increased body weight gain of broilers, but did not affect feed conversion or mortality. Optimum body weight gain was achieved at 80 mg/kg supplemental zinc, which exceeds the NRC recommendations of 40 mg/kg. 5. During each excreta collection period, increased supplemental zinc concentrations significantly increased zinc excretion. However, the zinc source did not influence zinc utilisation. 6. As compared with zinc sulphate supplementation, the cumulative zinc excretion data indicate that adding zinc to the basal diet in the form of Availa®Zn amino acid complex decreased zinc excretion.

Mobility and Availability to Plants of Two Zinc Sources Applied to a Calcareous Soil

The objective of this study was to compare the migration, availability, and relative effectiveness of Zn from liquid Zn‐amino acids (Zn‐AA) and Zn‐DTPA‐HEDTA‐EDTA (Zn‐CH: DTPA, diethylenetriaminepentaacetate; HEDTA, N‐2‐hydroxyethyl‐ethylenedinitrilotriacetate; EDTA, ethylenedinitrilotetraacetate) sources by applying different Zn levels to a calcareous soil in incubation, column, and greenhouse experiments. Zinc soil behavior was evaluated by sequential fractionation, and DTPA and Mehlich‐3 extractions. The results of the incubation study showed that amounts of Zn in the most labile fraction (water soluble plus exchangeable) were detected only when Zn‐CH fertilizer was applied. A large portion of Zn applied to soil occurred in the amorphous Fe oxide bound fraction in all fertilization treatments. The results of the column study showed that addition of Zn‐CH resulted in greatly increased mobility of Zn through the column as compared with the control and the Zn‐AA source, and 49% of Zn applied as Zn‐CH was leached from the column. The results of the greenhouse study showed in the absence of leaching that the application of two Zn sources significantly increased maize (Zea mays L.) dry matter yield compared with the control treatment although the increase in the Zn dosage did not increase dry matter further. The fertilizer treatments also significantly increased Zn concentration in plants, except the lowest dosage of Zn‐AA. Zn‐CH was more effective than Zn‐AA. The differences in plant Zn uptake in the greenhouse experiment between two Zn sources was correlated with the water soluble plus exchangeable fraction and DTPA extractable Zn in the incubation experiment.

Mobility and Availability to Plants of Two Zinc Sources Applied to a Calcareous Soil

The objective of this study was to compare the migration, availability, and relative effectiveness of Zn from liquid Zn-amino acids (Zn-AA) and Zn-DTPA-HEDTA-EDTA (Zn-CH: DTPA, diethylenetriaminepentaacetate; HEDTA, N-2-hydroxyethyl-ethylenedinitrilotriacetate; EDTA, ethylenedinitrilotetraacetate) sources by applying different Zn levels to a calcareous soil in incubation, column, and greenhouse experiments. Zinc soil behavior was evaluated by sequential fractionation, and DTPA and Mehlich-3 extractions. The results of the incubation study showed that amounts of Zn in the most labile fraction (water soluble plus exchangeable) were detected only when Zn-CH fertilizer was applied. A large portion of Zn applied to soil occurred in the amorphous Fe oxide bound fraction in all fertilization treatments. The results of the column study showed that addition of Zn-CH resulted in greatly increased mobility of Zn through the column as compared with the control and the Zn-AA source, and 49% of Zn applied as Zn-CH was leached from the column. The results of the greenhouse study showed in the absence of leaching that the application of two Zn sources significantly increased maize (Zea mays L.) dry matter yield compared with the control treatment although the increase in the Zn dosage did not increase dry matter further. The fertilizer treatments also significantly increased Zn concentration in plants, except the lowest dosage of Zn-AA. Zn-CH was more effective than Zn-AA. The differences in plant Zn uptake in the greenhouse experiment between two Zn sources was correlated with the water soluble plus exchangeable fraction and DTPA extractable Zn in the incubation experiment.

Effects of Feeding Complexed Zinc, Manganese, Copper, and Cobalt to Late Gestation and Lactating Dairy Cows on Claw Integrity, Reproduction, and Lactation Performance

Three hundred multiparous Holstein cows (150 cows per treatment) were blocked according to calving date and randomly assigned to a study to determine the effect of trace mineral source on incidence and severity of claw lesions, reproduction, and lactation performance of dairy cattle. Treatments were 1) all trace minerals supplied by sulfates(ITM)or 2) 360mg Zn from Zn amino acid complex, 200mg Mn from Mn amino acid complex, 125mg Cu from Cu amino acid complex, and 12mg Co from Co glucoheptonate per day(CTM;Availa®; Zinpro Corporation, Eden Prairie, MN) replacing an equivalent amount of Zn, Mn, Cu, and Co from sulfates. Cows received assigned treatments from 21 d prior to calving through 250 d of lactation. Cows fed CTM produced 1.2kg more (P < 0.05) milk, energy-corrected milk, and 3.5% fat-corrected milk than cows supplemented with ITM. The CTM treatment reduced (P < 0.05) days open by 22 d and tended to increase (P < 0.15) percentage of cows pregnant by 150 d in milk (54.8% vs 42.7%) and first service conception rate (27.4% vs 18.4%). Cows fed CTM tended to have a lesser incidence (P < 0.15) of claw disorders than cows fed inorganic trace minerals at 75 d postpartum (23.6% vs 34.1%) and numerically lower incidence at 250 d postpartum (10.0% vs 17.7%). The CTM treatment increased yield of milk, decreased days open, and tended to increase first service conception rates, increase percentage of cows pregnant at 150 d in milk, and decrease claw disorders at 75 d postpartum.

Effect of feeding organic and inorganic sources of additional zinc on growth performance and zinc balance in nursery pigs.

Three experiments were conducted to evaluate the effect of feeding pharmacological concentrations of zinc (Zn), from organic and inorganic sources, on growth performance, plasma and tissue Zn accumulation, and Zn excretion of nursery pigs. Blood from all pigs was collected for plasma Zn determination on d 14 in Exp. 1, d 7 and 28 in Exp. 2, and d 15 in Exp. 3. In Exp. 1, 2, and 3, 90, 100, and 15 crossbred (GenetiPorc USA, LLC, Morris, MN) pigs were weaned at 24+/-0.5, 18, and 17 d of age (6.45, 5.47, and 5.3 kg avg initial BW), respectively, and allotted to dietary treatment based on initial weight, sex, and litter. A Phase 1 nursery diet was fed as crumbles from d 0 to 14 in Exp. 1, 2, and 3, and a Phase 2 nursery diet was fed as pellets from d 15 to 28 in Exp. 1 and 2. The Phase 1 and Phase 2 basal diets were supplemented with 100 ppm Zn as ZnSO4. Both dietary phases contained the same five dietary treatments: 150 ppm additional Zn as zinc oxide (ZnO), 500 ppm added Zn as ZnO, 500 ppm added Zn as a Zn-amino acid complex (Availa-Zn 100), 500 ppm added Zn as a Zn-polysaccharide complex (SQM-Zn), and 3,000 ppm added Zn as ZnO. Overall in Exp. 1, pigs fed 500 ppm added Zn as SQM-Zn or 3,000 ppm added Zn as ZnO had greater ADG (P < 0.05) than pigs fed 150 ppm, 500 ppm added Zn as ZnO, or 500 ppm added Zn as Availa-Zn 100 (0.44 and 0.46 kg/d vs 0.35, 0.38, and 0.33 kg/d respectively). Overall in Exp. 2, pigs fed 3,000 ppm added Zn as ZnO had greater (P < 0.05) ADG and ADFI than pigs fed any other dietary treatment. On d 14 of Exp. 1 and d 28 of Exp. 2, pigs fed 3,000 ppm added Zn as ZnO had higher (P < 0.05) plasma Zn concentrations than pigs on any other treatment. In Exp. 3, fecal, urinary, and liver Zn concentrations were greatest (P < 0.05) in pigs fed 3,000 ppm added Zn as ZnO. On d 10 to 15 of Exp. 3, pigs fed 3,000 ppm added Zn as ZnO had the most negative Zn balance (P < 0.05) compared with pigs fed the other four dietary Zn treatments. In conclusion, feeding 3,000 ppm added Zn as ZnO improves nursery pig performance; however, under certain nursery conditions the use of 500 ppm added Zn as SQM-Zn may also enhance performance. The major factor affecting nutrient excretion appears to be dietary concentration, independent of source.