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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 aim of this study was to determine the effect of the supplementation of a slow-release bolus of zinc (Zn), selenium (Se), and cobalt (Co) at late gestation (6 week prepartum) on performance and some blood metabolites of Mehraban ewes and their lambs until weaning. Seventy pregnant ewes, 6 weeks prior to expected lambing, were randomly divided into two groups (35 heads each) including (1) control group and (2) slow-release bolus group. Blood samples of ewes were obtained on day 10 prepartum and 45 and 90 days postpartum, and milk samples were collected on day 45. Blood samples of lambs were collected on days 10, 45, and 90. Body weight at birth and weaning and average daily gain were higher and percentage of mortality and white muscle disease rate were lower in lambs whose mothers were given a bolus (P < 0.05). Slow-release bolus administration increased serum alkaline phosphatase and whole blood glutathione peroxidase activity, plasma concentrations of Zn, Se, and vitamin B 12 in ewes and their lambs (P < 0.05). In addition, serum creatine phosphokinase activity of lambs whose mothers were given bolus was lower (P < 0.05). Serum concentration of T 3 in bolus given ewes and their lambs was higher (P < 0.05) and serum T 4 concentration was lower (P < 0.05). Zinc, Se, and vitamin B 12 concentrations in milk were significantly higher in treated ewes (P < 0.05). Obtained results showed that maternal supplementation of zinc, selenium, and cobalt as slow-release ruminal bolus in late pregnancy improved some mineral status of ewes and their lambs until weaning and led to higher body weights of lambs at weaning.

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.

This study was conducted to evaluate the effects of dietary supplementation of different sources of zinc on the quantitative and qualitative characteristics of semen and blood testosterone in Mahabadi mature bucks. Twenty-four mature male goats (40 ± 0.86 kg), approximately 1-1.5 years old, were divided into three groups (n = 8) and assigned to experimental treatments for 56 days in a completely randomized design. The treatments included: 1. control (a basal diet containing 22.14 mg/kg zinc without zinc supplement), 2. basal diet + 35 mg/kg Zn as ZnSO4 (an inorganic source of Zn), and 3. basal diet + 35 mg/kg Zn as ZnMet (an organic source of Zn). Qualitative (ejaculate volume, sperm concentration) and quantitative (viability, membrane integrity, morphology, and CASA detected parameters) properties of semen and plasma testosterone and Zn, Cu, and Fe concentrations were evaluated. Results showed that ZnMet vs. ZnSO4 increased sperm membrane integrity and plasma Zn concentration and reduced morphologically abnormal spermatozoa (P=0.05), but there were no significant differences in other parameters. Viability, membrane integrity, morphology, some of the CASA detected parameters (total motility, straight-line velocity, average path velocity, beat cross frequency of sperm), and the plasma concentration of testosterone in zinc-supplemented groups was significantly higher than the control group. In conclusion, the positive effects of an organic source of Zn were seen in reducing abnormal spermatozoa and improving membrane integrity, plasma Zn concentration, and plasma testosterone concentration. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effects of dietary zinc (Zn) source and level of supplementation on performance, egg quality, blood parameters, and egg yolk Zn content in laying hens from 28 to 36 weeks of age. Two hundred laying hens (Hy-Line W-36) were weighed individually and placed randomly in cages with five treatments, five replicates of 8 birds in each using a 2×2+1 factorial arrangement. Treatments consisted of a control diet (cornsoybean meal as a basal diet without Zn supplementation) and the diet supplemented with 80 and 120 mg of Zn/kg, added as either Zinc-sulfate (ZnSulf) or Zn-methionine (ZnMet), respectively. Treatments did not impact on the laying hen performance. Eggshell thickness was improved (P<0.001) by ZnMet in comparison to ZnSulf. Eggshell thickness improved by increasing Zn from 80 to 120 mg/kg of the diet (P<0.05). Plasma HDL (P<0.001), alkaline phosphatase activity (P<0.05), total protein, and albumin concentrations (P<0.001) increased by ZnMet in comparison to ZnSulf supplementation. Plasma Fe, Cu, Zn, and P, and Zn contents of the egg yolk were not affected by Zn sources or levels. Plasma Ca was higher in hens receiving 120 mg/kg ZnMet/kg than other treatments (P<0.01). In conclusion, more positive effects on eggshell quality and some blood parameters were found by dietary ZnMet supplementation at 80 or 120 mg/kg diet than ZnSulf in laying hens under the conditions of this study. [ABSTRACT FROM AUTHOR]

In late pregnancy and early lactation, ewe's demand increases for zinc (Zn), and selenium (Se) for scavenging of free radicals and due to transfer via placenta, colostrum or milk to lamb.This experiment was conducted to study the effect of slow-release bolus of Zn and Se on performance, and some blood parameters of pregnant ewes in the last third of pregnancy, and early lactation as well as their lambs. Twenty-one ewes were estrus synchronized in the breeding season by intra vaginal insertion of sponge containing medroxyprogesterone acetate. Forty-five days before the expected date of parturition, the pregnant ewes (3–4 years old and 55±5.2 kg in weight) were randomly assigned to one of the three groups: 1) control, 2) slow-release glass bolus with mean release of 20 mg Zn and 0.2 mg Se per day (Bolus), and 3) 20 mg Zn and 0.2 mg Se per day as sulfate and selenite, respectively via Daily feeding (Daily). Blood samples were obtained from ewes at 105th and 135th days of pregnancy, at parturition and 15th day postpartum and from lambs at 15 days of age. The results indicated that total feed intake of ewes increased (P = 0.03) in the Bolus and Daily groups than control. Supplementation of Zn and Se in both methodssignificantly increased Total Antioxidant Capacity (TAC) in the ewesand their lambs than the control group. Compared with the control, there was higher triiodothyronine (T 3) in ewes and their lambs and lower tetraiodothyronine (T 4) only in lambs in Bolus and Dailygroups. Increased T 3 to T 4 ratio in ewes (at days 135 of pregnancy and at parturition) and their lambs was recorded in Bolus and Daily than the control group. An increased level of alkalinephosphatase (ALP) in ewes was observed in the Bolus and Daily groups compared with the control. Alanine amino transferase (ALT) activity on day 135 of pregnancy was significantly reduced by Zn and Se supplementation in both methods. Bolus and Daily groups of ewes had lower creatinephosphokinase (CPK), and their lambs had lower aspartate amino transferase (AST), ALT, CPK, and gamma-glutamyltransferase (GGT) than the control group. Regardless of the supplementation method, Zn and Se increased glucose (P = 0.02) and decreased triglyceride (P = 0.06) in ewes. In the ewes supplemented with Zn and Se, creatinine concentration significantly decreased in parturition day compared to control. Total protein, albumin, globulin and ratio of albumin to globulin in ewes and their lambs were not different between treatments. As a result, Zn and Se improved antioxidant status and some blood parameters in ewes and their lambs. Efficacy of slow-release bolus of Zn and Se was similar with daily feeding of these elements. • Supplementation of Zn and Se improved performance of ewes and their lambs. • Efficacy of slow-release bolus of Zn and Se was similar with daily feeding method. • There Was no difference between the use of zinc oxide and zinc sulfate on parameters of ewes and their lambs. • Boluses would be recommended when animals are not fed especially in extensive grazing situations. [ABSTRACT FROM AUTHOR]

Abstract: An experiment of 70days was conducted on 20 male lambs (6–7months of age) to determine the effects of Zn supplementation (ZnSo4 and Zn-proteinate) in a barley based diet on mineral profile, some serum and plasma metabolites and performance in lambs. Animals were randomly allotted to 4 treatments including;1) basal diet containing 22.47mg Zn/kg DM, without supplementary Zn (control); 2) basal diet+40mg Zn/kg DM as ZnSO4 (ZnSO4 40); 3) basal diet+20mg Zn/kg DM as Zn-proteinate (Zn-Pro 20), and 4) basal diet+40mg Zn/kg DM as Zn-proteinate (Zn-Pro 40). The basal diet was provided according to NRC (2007) to meet or exceed lambs requirements except Zn. Blood samples were taken on days 28, 30, 65 and 70 before morning feeding. Daily feed intake, plasma Ca and Cu and beta-carotene concentration did not differ significantly between treatments. Plasma Zn concentration, serum vitamin A concentration, alkaline phosphatase (ALP) and superoxide dismutase (SOD) activity differed significantly between control and Zn supplemented groups (P <0.05) as Zn supplementation improved these parameters. Average daily gain and feed efficiency improved with Zn supplementation (P <0.05). The results of this study show that Zn improved performance of lambs and adding 20mg Zn/kg DM to the basal diet might be sufficient to meet the Zn requirement of the lambs. [Copyright &y& Elsevier]