有机源锌和锰对蛋鸡生产性能、蛋壳和骨质量的影响

文章旨在研究日粮添加有机源锌和锰替代无机锌和无机锰对蛋鸡生产性能、蛋壳和骨骼质量的影响。试验选择31周龄产蛋性能接近的罗曼粉壳蛋鸡616只,随机分为7组,每组4个重复,每个重复22只。基础日粮锌和锰含量分别为50和30 mg/kg,对照组饲喂基础日粮,分别添加氧化锌和硫酸锰(锌40 mg/kg,锰60 mg/kg)。处理组分别在基础日粮中添加20 mg/kg有机锌,30 mg/kg有机锰、20 mg/kg有机锌+30 mg/kg有机锰、40 mg/kg有机锌、60 mg/kg有机锰、40 mg/kg有机锌+60 mg/kg有机锰,上述含量均以相应元素计。试验共进行7周。结果显示:日粮用有机锌或锰替代50%或100%无机锌、锰对蛋鸡生产性能相关参数均无显著影响(P> 0.05)。对照组相比,有机锌或锰替代无机锌或锰的比例对32、46、60和74周龄蛋鸡蛋壳相对重量、蛋壳密度和蛋壳厚度均无显著影响(P> 0.05)。与对照组相比,30 mg/kg有机锰、20 mg/kg有机锌+30 mg/kg有机锰组的蛋壳强度显著提高(P <0.05)。40 mg/kg有机锌+60 mg/kg有机锰组较无机锌、锰组显著提高了60、74周龄及全期蛋壳强度(P <0.05)。日粮添加有机锌或锰对胫骨物理参数及胫骨和趾骨灰分含量均无显著影响。结论 :日粮添加有机锌、锰替代无机锌锰对蛋鸡产蛋性能和骨质量无影响,但可以降低蛋鸡由于年龄升高对蛋壳强度的负面影响。     

氨基酸络合微量元素替代部分硫酸盐对蛋鸡产蛋性能及组织抗氧化机能的影响

试验选择144只3周龄海兰褐壳蛋小鸡,随机分成2个日粮处理组,A为实用日粮,硫酸盐形式Zn、Cu、Mn的添加水平分别为60、10、60mg/kg;B为试验日粮,用氨基酸络合形式的锌、铜、锰替代约70%硫酸盐形式锌、铜、锰的添加量。无机和有机Zn、Cu、Mn的剂量组合为20+40、3+7和20+40mg/kg。试验时间为62周。研究结果表明,氨基酸锌、铜、锰部分替代无机盐对产蛋鸡产蛋性能、蛋品质、牛血清白蛋白(BSA)抗体反应没有显著影响,但显著提高了45周龄蛋鸡血液淋巴细胞对有丝分裂源(ConA和LPS)的增殖反应及皮肤嗜碱性过敏反应(P<0.05),显著增加了45周龄蛋鸡肝脏组织总抗氧化力,降低了脂质过氧化物丙二醛(MDA)的含量(P<0.05)。     

日粮中不同水平、不同来源的锰、锌和铜对蛋鸡产蛋量及其质量性状的影响(一)

试验旨在研究蛋鸡日粮中不同来源的Zn、Mn和Cu(有机vs.无机)对产蛋性能和蛋壳质量的影响。选择180羽38周龄的W36来航蛋鸡随机分到36个蛋鸡笼中,每笼5羽蛋鸡,采食6种试验日粮,每6笼为1个处理组。试验期为38~53周龄。其中3个试验处理,基础日粮中分别含有无机锌、无机锰和无机铜65mg/kg、75mg/kg、7mg/kg;65mg/kg、75mg/kg、7mg/kg;40mg/kg、40mg/kg、7mg/kg。另外的3个试验处理,基础日粮中分别含有有机锌、有机锰和有机铜20mg/kg、20mg/kg、3.5mg/kg;40mg/kg、40mg/kg、7.5mg/kg;60mg/kg、60mg/kg、10.5mg/kg。试验数据表明,日粮处理对蛋鸡的采食量(P0.001)、饲料转化率(P0.001)和破蛋率(P0.05)有显著影响。用锌和铜的氧化物(分别为65mg/kg和75mg/kg)来替代蛋鸡日粮中相同剂量的锌和锰的硫酸盐可显著提高蛋鸡的采食量、饲料转化率、降低破蛋率和哈氏单位(P0.05)。当日粮中锌和锰的氧化物和铜的硫酸盐(分别为65mg/kg、75mg/kg和7mg/kg)被20mg/kg、20mg/kg和3.5mg/kg的相应氨基酸复合物代替后,蛋鸡仍能保持原有的生产性能。试验结果显示,在玉米-豆粕型日粮中添加比NRC要求低50%~70%的有机锌、有机锰、有机铜即能满足蛋鸡的生产需要,又能提高蛋鸡的蛋壳和蛋白品质。     

不同水平蛋氨酸锌对冬毛期蓝狐营养物质消化率及微量元素排出的影响

试验研究了日粮中添加蛋氨酸锌(Zn-Met)对冬毛期蓝狐营养物质利用率及粪中微量元素的影响。试验选用150只体重相近的冬毛期蓝狐，随机分为5组，每组30只。对照组饲喂基础日粮，试验组在基础日粮中分别以Zn-Met形式添加30、60、90、120 mg/kg锌。结果表明：在日粮中添加适量蛋氨酸锌可使粗蛋白、钙、磷的消化率提高，其中B组（30 mg/kg）的添加水平效果最佳，差异显著(P<0.05)，对干物质、粗脂肪的消化率无显著性影响；蛋氨酸锌减少了微量元素铁、铜、锌、锰的排泄量，减少了环境的污染，与对照组相比，B组（30 mg/kg）和C组（60 mg/kg）效果差异显著(P<0.05)；综上所述，冬毛生长期蓝狐日粮中蛋氨酸锌的最适添加水平为30~60 mg/kg。     

日粮钙水平和额外添加有机锌、锰对延养期蛋鸡产蛋性能和蛋品质的影响

试验旨在研究日粮钙水平及额外添加有机锌、锰对蛋鸡延养期产蛋性能和蛋品质的影响。试验选取144只107周龄大午金凤蛋鸡,采用2×2双因子设计随机分为4组,分别为基础日粮组(N,日粮钙水平3.5%,不额外添加有机锌、锰);高钙组(h C,日粮钙水平5.0%,不额外添加有机锌、锰);高锌锰组(h ZM,日粮钙水平3.5%,额外添加有机锌40 mg/kg+有机锰30 mg/kg);高钙锌锰组(h CZM,日粮钙水平5.0%,额外添加有机锌40 mg/kg+有机锰30 mg/kg)。每个处理6个重复,每个重复6只鸡。试验期6周。结果表明:与3.5%的钙水平相比,5.0%的钙水平能够显著提高延养期蛋鸡日产蛋率、平均日产蛋重及蛋壳强度(P0.05),料蛋比和蛋黄占比均显著降低(P0.05),且有提高蛋黄颜色和蛋形指数、降低哈夫单位的趋势(0.05≤P0.10)。额外添加有机锌、锰,有降低破损蛋率和蛋黄颜色的趋势(0.05≤P0.10),对其他产蛋性能及蛋品质均无显著影响(P0.05)。钙和有机锌、锰无交互作用(P0.05)。当日粮钙水平为5.0%时,可以显著提高延养期蛋鸡产蛋性能及蛋品质;额外添加有机锌、锰对延养期蛋鸡有降低破损蛋率、蛋黄颜色趋势。二者无交互作用。     

铁与维生素A及其互作效应对蛋鸡微量元素铁、锰、锌表观

选用210日龄蛋鸡432只,随机分为6组,每组6个重复,每重复12只鸡,采用3&#215;2（Fe&#215;VA）完全随机试验设计,研究日粮中不同水平Fe和VA对蛋鸡产蛋高峰期（30～33周龄和34～37周龄）铁、锰、锌表观存留率的影响。日粮铁的添加量分别为0、30、60mg／kg,VA的添加量分别为4000、8000IU／kg。结果表明：日粮不同铁水平对前后期铁、锰表观存留率影响均显著（P〈0．05）;日粮VA水平对前后期铁表观存留率的影响均显著（P〈0．05）;对后期锰表观存留率影响显著（P〈0．05）;对前期锌表观存留率影响显著（P〈0．05）;铁和维生素A的交互作用对前后期铁、锰、锌表观存留率的影响均显著（P〈0．05）。结果表明日粮中铁添加量为30mg／kg、VA添加量为4000IU／kg时蛋鸡Fe、Mn、Zn表观存留率最佳。     

不同形态的铜对猪生长性能及血清GH、血浆NPY水平的影响

将75头体质量约20kg的“军牧1号”白猪，分成A、B、C、D、E组。A组为对照组，饲以基础日粮，B、C2组分别饲以添加122．5、250mg／kg铜(硫酸铜)的日粮；D、E2组分别饲以添加122．5、250mg／kg蛋氨酸铜的日粮，观测不同形态的铜对仔猪生长性能以及血液GH、血浆NPY水平的影响。结果显示：日粮中添加2种铜均能促进仔猪的生长，提高饲料利用率，升高血液中GH和血浆NPY水平，但对采食量没有显著影响，2种铜源在相同浓度下对猪的促生长性能无差异。     

22～42日龄肉鸡铜、铁、锌、锰不同用量组合的研究

本试验旨在研究饲粮中铜、铁、锌、锰含量对22~42日龄肉鸡生长性能和粪中铜、铁、锌、锰排泄量的影响,进而对微量元素的平衡模式进行探讨。选取940只1日龄爱拔益加(AA)肉公鸡,1~21日龄统一饲喂铜、铁、锌、锰含量分别为16.96、166.66、46.01、60.26 mg/kg的玉米-豆粕型饲粮。试验选用22日龄、体况良好、体重接近的AA肉公鸡900只,随机分为15组,每组6个重复,每个重复10只鸡。对照组饲喂基础饲粮,基础饲粮中铜、铁、锌、锰含量分别为8、125、40、60 mg/kg,试验组饲喂在基础饲粮中按照均匀设计原则添加2~8 mg/kg铜、10~35 mg/kg铁、10~40 mg/kg锌、15~60 mg/kg锰组成的14种试验饲粮。测定肉鸡试验期生长性能,并于38~42日龄时采集粪样测定铜、铁、锌、锰含量。结果表明:1)饲粮铜、铁、锌、锰含量在NRC推荐量至2倍NRC推荐量范围时,对22~42日龄肉鸡的平均日增重(ADG)和料重比(F/G)无显著影响(P0.05)。2)由最优解分析得出,粪中铜排泄量最低为23.11 mg/kg时,饲粮铜、铁、锌、锰含量分别为7.15、116.28、82.82、60.95 mg/kg;铁排泄量最低为438.34 mg/kg时,饲粮铜、铁、锌、锰含量分别为14.78、116.81、38.15、63.72 mg/kg;锌排泄量最低为102.60 mg/kg时,饲粮铜、铁、锌、锰含量分别为7.69、127.40、40.70、133.26 mg/kg;锰排泄量最低为159.37 mg/kg时,饲粮铜、铁、锌、锰含量分别为11.07、136.97、46.13、59.05 mg/kg;粪中铜、铁、锌、锰总排泄量最低为218.94 mg/kg时,饲粮铜、铁、锌、锰含量分别为7.36、125.74、38.23、62.76 mg/kg。综上所述,饲粮铜、铁、锌、锰含量在NRC推荐量至2倍NRC推荐量范围时对22~42日龄肉鸡的生长性能无显著影响;粪中铜、铁、锌、锰任一元素的排泄量均受饲粮中其他微量元素添加量的影响,且针对不同元素最低排泄量存在不同的最佳组合;饲粮铜、铁、锌、锰的含量分别为7.36、125.74、38.23、62.76 mg/kg时,能够满足肉鸡微量元素需要量,同时粪中铜、铁、锌、锰总排泄量最小。     

锌对蛋鸡生产性能的影响研究

为研究锌对蛋鸡生产性能的影响,选取了1 000只360日龄的蛋鸡作为研究对象,将其随机分为四个组,每组均为250只,即对照组添加60 mg/kg一水硫酸锌与试验A组添加60 mg/kg乳酸锌、试验B组添加40 mg/kg乳酸锌、试验C组添加60 mg/kg锌,对比四组的蛋鸡产生性能,选择出适宜的添加剂量。结果显示,锌对蛋鸡生产性能有着较大的影响,在日粮中添加60 mg/kg乳酸锌的效果最佳,能够更好的提高蛋鸡生产性能。     

铁与维生素A及其互作效应对蛋鸡微量元素铁、锰、锌表观存留率的影响

选用210日龄蛋鸡432只,随机分为6组,每组6个重复,每重复12只鸡,采用3×2(Fe×VA)完全随机试验设计,研究日粮中不同水平Fe和VA对蛋鸡产蛋高峰期(30～33周龄和34～37周龄)铁、锰、锌表观存留率的影响。日粮铁的添加量分别为0、30、60mg/kg,VA的添加量分别为4000、8000IU/kg。结果表明:日粮不同铁水平对前后期铁、锰表观存留率影响均显著(P<0.05);日粮VA水平对前后期铁表观存留率的影响均显著(P<0.05);对后期锰表观存留率影响显著(P<0.05);对前期锌表观存留率影响显著(P<0.05);铁和维生素A的交互作用对前后期铁、锰、锌表观存留率的影响均显著(P<0.05)。结果表明日粮中铁添加量为30mg/kg、VA添加量为4000IU/kg时蛋鸡Fe、Mn、Zn表观存留率最佳。     

耐镉乳酸菌对蛋鸡组织和鸡蛋中镉残留及部分矿物元素沉积的影响

试验旨在探明耐镉乳酸菌对蛋鸡的脏器系数、镉在蛋鸡组织及鸡蛋中的残留及钙、铁、锌、锰、铜和硒在组织和鸡蛋中沉积的影响。试验分为5组：对照组,饲喂基础日粮;镉组,基础日粮+5 mg/kg镉（以氯化镉的形式添加）;乳酸菌组,基础日粮+1×10¹⁰ CFU/kg耐镉乳酸菌;镉+低剂量乳酸菌组,基础日粮+5 mg/kg镉+1×10¹⁰ CFU/kg耐镉乳酸菌;镉+高剂量乳酸菌组,基础日粮+5 mg/kg镉+1×10¹¹ CFU/kg耐镉乳酸菌,试验期6周。试验期末,采集各组蛋鸡血液,测定总抗氧化力（T-AOC）和超氧化物歧化酶（SOD）活力;采集各组蛋鸡内脏组织和鸡蛋,计算脏器系数,同时测定组织和鸡蛋中镉、钙、铁、铜、锌、锰及硒元素含量。结果显示,与对照组相比,镉及乳酸菌组显著提高了蛋鸡总抗氧化能力（P<0.05）。各处理组中,镉组脾脏指数最低,镉加乳酸菌组脾脏指数显著高于镉组（P<0.05）;与对照组相比,乳酸菌组显著提高心脏指数（P<0.05）。镉组致蛋鸡肝脏和肾脏中镉残留量远高于其他组织,补加耐镉乳酸菌显著减少了心脏的镉残留量（P<0.05）。与对照组相比,镉组显著降低肾脏钙、脾脏和卵黄的锰含量（P<0.05）;与对照组相比,镉加低剂量耐镉乳酸菌显著增加肾脏锰含量、卵黄铁含量及肾脏和脾脏铜含量（P<0.05）;镉在鸡蛋中的残留量较低,与对照组相比,镉组显著降低鸡蛋铁、锰元素含量（P<0.05）,补加耐镉乳酸菌显著增加铁、锌、锰和硒元素含量（P<0.05）。结果表明,在蛋鸡日粮中添加1×10¹⁰ CFU/kg的耐镉乳酸菌,可显著提高蛋鸡血清总抗氧化力水平和蛋鸡的心脏指数,显著改善镉暴露导致的脾脏萎缩和心脏镉的残留量;同时显著增加锰、铜、铁在肾脏、脾脏及卵黄中的含量及铁、锌、锰和硒在鸡蛋中的含量。     

Effect of dietary supplementation of organic zinc on laying performance,egg quality and some biochemical parameters of laying hens

This study was conducted to evaluate the effects of zinc methionine (Zn‐Met) supplementation on the performance, egg quality, antioxidant status and some biochemical parameters of blood serum in laying hens from 22 to 34 weeks of age. A total of 120 Hisex Brown laying hens of 22‐week‐old were randomly allocated into five treatments with six cage replicates for each (four hens/replicate). Dietary treatments consisted of the basal diet with no Zn‐Met supplementation (control group) and basal diet supplemented with 25, 50, 75 or 100 mg Zn‐Met/kg diet. No significant differences were observed on body weight, body weight gain or feed conversion ratio due to dietary Zn‐Met supplementation. However, highly significant impact was observed on daily feed intake. Egg number, egg weight and egg mass were increased in the group fed diet supplemented with the highest level of Zn‐Met (100 mg/kg of diet) as compared to other groups. All egg quality traits were statistically (p > .05 or .01) affected as a response to dietary Zn‐Met supplementation except egg shape index, shell percentage and yolk index. In comparison with the control group, dietary supplementation of 25, 50, 75 or 100 mg Zn‐Met/kg decreased serum triglyceride and LDL‐cholesterol levels. Serum cholesterol level was increased with all dietary levels of Zn‐Met in comparison with the control group. Dietary Zn‐Met supplementation increased the serum content of zinc, where the highest values were recorded with 50 and 100 mg Zn‐Met/kg diet. Dietary Zn‐Met levels did not affect the antioxidant indices in blood serum except for the activity of copper–zinc superoxide dismutase (Cu‐Zn‐SOD). The activity of Cu‐Zn‐SOD was increased with Zn‐Met supplementations with no differences among supplemental zinc levels. It is concluded that dietary Zn‐Met supplementation reduced serum triglyceride, LDL‐cholesterol and increased Zn status and resulted in promoting antioxidant ability of laying hens, and the addition of 100 mg Zn‐Met/kg to layer diet was appropriate for improving the above parameters in addition to egg production indices and Haugh unit score.     

Effect of dietary trace mineral concentration and source (inorganic vs. chelated) on performance, mineral status, and fecal mineral excretion in pigs from weaning through finishing

Two hundred and sixteen weanling gilts (6.65+/-0.08 kg) were used to determine the effects of decreasing supplemental concentrations of Zn, Cu, Fe, and Mn, and trace mineral source (inorganic vs. chelated) on growth performance, mineral status, and fecal mineral concentrations from weaning through development. The study was conducted over three trials with 72 pigs in each trial. Gilts were blocked by weight and randomly assigned to either 1) control, 2) reduced inorganic, or 3) reduced chelated trace minerals. The control diet was supplemented with 25, 150, 180, and 60 mg/kg of Cu, Zn, Fe, and Mn (in sulfate forms), respectively, during the nursery phase and 15, 100, 100, and 40 mg/kg of supplemental Cu, Zn, Fe, and Mn, respectively, during the growing and gilt-developer phases. Reduced inorganic and reduced chelated treatments were supplemented during all phases with 5, 25, 25, and 10 mg/kg of Cu, Zn, Fe, and Mn, respectively. The reduced chelated treatment supplied 50% of the supplemental Cu, Zn, Fe, and Mn in the form of metal proteinates, with the remainder from sulfate forms. Performance by control pigs did not differ from pigs fed the reduced trace mineral treatments during the nursery and grower-development periods. Gain:feed was lower (P < 0.05) for pigs fed the reduced inorganic compared with those fed the reduced chelated treatment during the nursery period. Trace mineral source did not affect performance during the growing or gilt-developer phase. Plasma Zn concentration and alkaline phosphatase activity were higher (P < 0.01) in control pigs than in those receiving reduced trace minerals during the nursery and growing phases. Plasma Cu concentration and ceruloplasmin activity were generally not affected by treatment. Hemoglobin concentrations were lower (P < 0.05) for the reduced inorganic compared with the reduced chelated treatment in the nursery phase. Fecal concentrations of Cu, Zn, and Mn were lower (P < 0.05) in pigs fed reduced trace minerals than in controls during all production phases. Fecal Zn concentration during the nursery and fecal Cu concentrations during the growing and gilt-developer phases were lower (P < 0.05) in pigs fed the reduced chelated compared with the reduced inorganic treatment. Results indicate that reducing the concentrations of Zn, Cu, Mn, and Fe typically supplemented to pig diets will greatly decrease fecal mineral excretion without negatively affecting pig performance from weaning through development.     

Early growth and environmental implications of dietary zinc and copper concentrations and sources of broiler chicks

1. Environmental accumulation of zinc and copper is becoming a concern in areas having intensive animal production. This study examined performance and excretion of broiler chicks given diets supplemented with graded concentrations of zinc and copper from three different sources. 2. Two experiments were conducted, each utilising 570 1-d-old chicks. In Experiment 1, chicks were given diets containing supplemental zinc concentrations from 40 to 120 mg/kg supplied as zinc sulphate, a zinc amino acid complex (Availa Zn), or a combination of zinc sulphate and Availa Zn with each contributing one-half of the total supplemental zinc. In Experiment 2, broiler chicks were given diets with graded concentrations of supplemental copper ranging from 4 to 12 mg/kg from copper sulphate, a copper amino acid complex (Availa Cu), or a combination of copper sulphate and Availa Cu with each contributing one-half of the total supplemental copper. 3. During the 17-d experimental period, mineral concentration or source did not influence body weight, feed conversion, or the incidence of mortality from 1 to 17 d. 4. Decreasing dietary zinc concentration from 120 to 40 mg/kg reduced zinc excretion by 50%. 5. Copper excretion was decreased by 35% as supplemental copper was reduced from 12 to 4 mg/kg. 6. Reducing dietary zinc and copper concentrations can potentially decrease the accumulation of heavy metals in the environment without compromising bird performance.     

Tolerance for excess basic zinc chloride and basic copper chloride in chicks

(1) Four chick experiments were conducted to determine toxicity estimates for basic zinc chloride (BZC) and basic copper chloride (BCC), now being used as sources for these minerals. (2) In experiment 1, New Hampshire x Columbian crossbred chicks were fed 0, 500, 1000, 1500, 3000 and 5000 mg Zn/kg from BZC (Zn5Cl2(OH)8). Broken-line regression analysis showed that the minimal toxic break points for chick weight gain and gain:food were 1720 and 2115 mg Zn/kg, respectively. (3) Crossbred chicks were fed 0, 150, 250, 500, 750 and 1000 mg Cu/kg from BCC (Cu2(OH)3C) in experiment 2. Regression analysis indicated that the minimal toxic break points for chick weight gain and gain:food were 642 and 781 mg Cu/kg, respectively. (4) In experiment 3, commercial broiler chicks were fed 0, 1500, 2000 and 2500 mg supplemental Zn/kg from BZC or 0, 500, 650 and 800 mg supplemental Cu/kg from BCC. Broiler chicks fed those high inclusion rates of Zn did not show reduced weight gain in comparison to chicks fed no supplemental Zn. All high concentrations of supplemental Cu depressed chick weight gain in comparison to control chicks. (5) Experiment 4 involved two separate 4 x 2 factorial designs with supplemental Zn (0, 2500, 3500 and 4500 mg/kg) or Cu (0, 500, 750 and 1000 mg/kg) and two breeds of chicks (crossbred and commercial). Significant interactions for weight gain, food intake, gain:food and liver Cu suggested that the crossbred and commercial chicks responded differently to high concentrations of supplementary dietary Cu.     

Effects of Dietary Phosphorous and Trace Mineral Source on Immune Function,Mineral Status,and Performance of Stressed Steers

Two experiments were conducted to determine the effects of dietary P and trace mineral source on immune response, mineral status, and performance in steers stressed by weaning and disease exposure. In Experiment 1, 24 Angus and 24 Simmental weaned steers were used. Treatments consisted of 1) inorganic trace minerals, 2) organic trace minerals, 3) 0.15% supplemental P + inorganic trace minerals, and 4) 0.15% supplemental P + organic trace minerals. Copper, Mn, and Zn were added to provide 10, 25, and 25 mg/kg DM, respectively. The organic treatments supplied 50% of the supplemental Cu and Mn, and 66% of the supplemental Zn from metal proteinates, with the remainder supplied by inorganic sulfate forms. Inorganic treatments supplied all of the supplemental Zn, Cu, and Mn from sulfate forms. The basal diet was a corn silage-soybean meal-based diet. On d 2 following weaning, steers received an intranasal inoculation of infectious bovine rhinotracheitis virus (IBRV). Rectal temperatures in response to IBRV inoculation were similar across treatments. On d 9, steers were injected with 10 ml of a 25% pig red blood cell (PRBC) suspension. Total Ig titers against PRBC concentrations were higher (P<0.05) in steers receiving no supplemental P on d 7 postinjection. However, IgG and IgM titers were unaffected by treatment. Cell-mediated immune response (CMI) to phytohemagglutinin (PHA), plasma Cu and Zn concentrations, and 38-d performance were unaffected by treatment. In Experiment 2, 35 Angus steers were fed diets containing either inorganic or organic trace minerals. Performance and percent morbidity were unaffected by treatment. Plasma Cu was higher for steers fed organic trace minerals. Results indicate that increasing dietary P or replacing inorganic trace minerals with organic forms had little effect on immunity or performance of steers stressed by weaning.     

Effects of zinc and vitamin A supplements on plasma levels of thyroid hormones, cholesterol, glucose and egg yolk cholesterol of laying hens

The effects of zinc and vitamin A supplementation to the diet on some blood metabolites were evaluated in Hisex brown laying hens from 56 weeks to 68 weeks of age. A total of 130 birds were divided into two main groups according to vitamin A treatment (0 and 3.44 mg retinyl acetate kg(-1) feed, respectively), each consisting of 65 hens. Hens in both of the main groups were then divided into five zinc treatment groups (0, 25, 50, 100 and 200 mg zinc kg diet(-1) respectively) of 13 hens each. It was observed that plasma T4, T3 and total cholesterol levels were affected by only zinc supplementation. While 100 and 200 mg Zn kg(-1) decreased plasma T4 level compared to control value, plasma T3 level was reduced by 100 mg Zn kg(-1) compared to groups fed less Zn. Adding 50 and 200 mg Zn kg(-1) to the diet increased plasma total cholesterol level in the birds compared to other groups. Vitamin A, zinc, and their interaction did not influence the concentration of plasma high-density lipoprotein (HDL)-cholesterol, glucose and egg yolk cholesterol in laying hens.     

Effect of Organically Complexed Copper,Iron, Manganese,and Zinc on Broiler Performance,Mineral Excretion,and Accumulation in Tissues

Supplementation of trace minerals with a large safety margin in broiler chickens has resulted in a high level of mineral excretion that ends up in the environment. Organically complexed trace minerals (organic minerals) may be able to replace the inorganic trace minerals, because the former appear to have a greater bioavailability. Therefore, a 29-d cage study that included diets with supplemental trace minerals from organic and inorganic sources based on a trace mineral deficient control diet was conducted to examine the possible response of broiler chickens to organic mineral supplements. The results showed that supplementation with 4 mg of Cu and 40 mg each of Fe, Mn, and Zn from organic sources may be sufficient for normal broiler growth to 29 d of age. It is possible to use these lower levels of organic trace minerals in broiler diets to avoid high levels of trace mineral excretion.     

Effects of breed (Angus vs Simmental) and copper and zinc source on mineral status of steers fed high dietary iron

Forty-four Angus (n = 24) and Simmental (n = 20) steers, averaging 301 kg initially, were used to determine the effects of breed and Cu and Zn source (SO4 or proteinate (Prot) form) on Cu and Zn status of steers fed high dietary iron (Fe). Steers were stratified by weight within breed and randomly assigned to treatments. Treatments consisted of: 1) CuSO4 + ZnSO4 ,2) CuSO4 + ZnProt, 3) CuProt + ZnSO4, and 4) CuProt + ZnProt. Copper and Zn sources were added to provide 5 mg Cu and 25 mg supplemental Zn/kg DM. All steers were individually fed a corn silage-based diet supplemented with 1,000 mg Fe (from FeSO4)/kg DM. Liver biopsy samples were obtained at the beginning and end of the 149-d study. Serum samples were collected initially and at 28-d intervals for determination of ceruloplasmin activity and Zn and Cu concentrations. Copper and Zn source did not affect performance, serum or liver Cu and Zn concentrations, or ceruloplasmin activity. Copper status decreased (P < 0.01) in all steers with time, and increasing the level of supplemental Cu from 5 to 10 mg/kg DM on d 84 did not prevent further drops in serum Cu and ceruloplasmin. Simmental steers had lower (P < 0.05) serum and liver Cu concentrations, and serum ceruloplasmin activity throughout the study. These results indicate that neither CuSO4 nor CuProt were effective at the supplemental concentrations evaluated in alleviating the adverse effect of high Fe on Cu status. Simmental steers had lower Cu status than Angus, suggesting a higher Cu requirement.