山药对断奶仔猪生长性能和腹泻率的影响

为了研究日粮中添加不同剂量山药对断奶仔猪生长性能和腹泻率的影响。选择28日龄断奶仔猪132头,随机分为对照组和试验组Ⅰ、Ⅱ、Ⅲ共4个处理组,各处理间试验仔猪体重经统计检验差异不显著（P〉0.05）。试验设1个对照组和3个试验组,每个处理组4个重复,每个重复8头猪,公母各半。对照组饲喂基础饲粮,3个试验组饲粮在基础饲粮基础上分别添加山药,添加量分别为0.05%、0.1%、0.2%。,试验期为28 d。结果表明,日粮中添加1%、2%山药对断奶仔猪具有促进生长,提高饲料转化率的功效,并且能够显著降低断奶仔猪的腹泻率;试验Ⅱ组、试验Ⅲ组之间差异不显著。综合来看以添加1%山药效果最好,将山药作为一种中草药饲料添加剂饲喂家畜会具有广阔的开发前景。     

甘露寡糖对断奶仔猪生长性能和腹泻率的影响

选取28日龄断奶的三元[杜×(大×长)]杂交仔猪96头,平均体重为(7.46±0.38)Kg,按体重和性别随机分为4个处理组,每个处理组3个重复,每个重复8头仔猪,公母各半。第1个处理组为空白组,第2、3、4个处理组在相同的基础日粮中分别添加0.1%、0.2%和0.4%的甘露寡糖,研究甘露寡糖对断奶仔猪生长性能和腹泻率的影响。结果表明:添加0.2%甘露寡糖组断奶仔猪的实验末重、日增重和饲料转化率显著优于其它三组(P<0.05),腹泻率极显著低于对照组(P<0.01)。     

纳米氧化锌对断奶仔猪生长性能及腹泻率的影响

本试验通过研究纳米氧化锌(Nano-ZnO)对断奶仔猪生长性能及腹泻率的影响,旨在进一步探寻较低剂量纳米氧化锌替代高锌的可行性.将135头23日龄断奶仔猪按照体重相近、遗传基础相似的原则分为5个处理组,每个处理组3个重复,每个重复9头,用纳米氧化锌和高剂量氧化锌(ZnO)进行饲养对比试验,试验期24 d.其中第1组为处理1组(0 mg/kg),第2,3,4组分别为200,400,600 mg/kg纳米氧化锌组,第5组为高锌组(3000 mg/kg ZnO).结果表明较处理1组(0 mg/kg)而言,无论是纳米氧化锌(200,400,600 mg/kg)还是高锌组(3000 mg/kg ZnO)均可极显著提高日增重(ADG)(P＜0.01);400 mg/kg纳米氧化锌组与高锌组(3000 mg/kg ZnO)在日增重方面差异不显著(P＞0.05).400 mg/kg纳米氧化锌降低腹泻率效果最好,较对照组(0 mg/kg)腹泻率降低49.1%,达到极显著性差异(P＜0.01),较高锌组(3000 mg/kg ZnO)腹泻率降低21.6%,达到极显著性差异(P＜0.01).根据ADG、平均日采食量(ADFI)、料肉比(F/G)、腹泻率等指标综合得出,第3组(400 mg/kg Nano-ZnO)可以达到甚至超过第5组高锌组(3000 mg/kg ZnO)效果.     

纳米氧化锌对断奶仔猪生长性能的影响

选用63头断奶仔猪,分为处理1组(3000mg/kg普通饲料级氧化锌)、处理2组(250mg/kg纳米氧化锌)、处理3组(500mg/kg纳米氧化锌)三个处理,每个处理3个重复,每个重复7头仔猪,试验期20d。结果表明:纳米氧化锌(500mg/kg)能显著提高断奶仔猪的日增重(与处理1组相比,提高9.91%),改善肉料比,有较好的经济效益。     

纳米氧化锌对断奶仔猪生长性能和肠黏膜屏障的影响

本文旨在研究纳米氧化锌对断奶仔猪生长性能和肠黏膜屏障的影响及其机理。选用96头平均体重为(5.7±0.2)kg的21日龄"杜×长×大"断奶仔猪,随机分成3组:1)对照组,饲喂基础饲粮;2)氧化锌组,饲喂在基础饲粮中添加3 000 mg/kg锌(氧化锌)的试验饲粮;3)纳米氧化锌组,饲喂在基础饲粮中添加300 mg/kg锌(纳米氧化锌)的试验饲粮。每组4个重复,每个重复8头仔猪,试验期14 d。结果表明:1)与对照组相比,纳米氧化锌组断奶仔猪平均日增重提高了7.26%(P<0.05),腹泻率降低了70.82%(P<0.05),但与氧化锌组差异不显著(P>0.05)。2)与对照组相比,纳米氧化锌组仔猪28和35日龄绒毛高度分别提高了12.64%和10.80%(P<0.05);28日龄隐窝深度降低了15.42%(P<0.05);28和35日龄绒毛高度/隐窝深度分别提高了33.61%和17.11%(P<0.05);28和35日龄血浆D-乳酸含量分别降低了28.97%和20.23%(P<0.05),二胺氧化酶活性分别降低了28.61%和24.92%(P<0.05)。氧化锌组和纳米氧化锌组之间各指标差异不显著(P>0.05)。结果提示,断奶仔猪饲粮中添加300 mg/kg锌(纳米氧化锌)可提高平均日增重,降低腹泻率,改善肠黏膜形态,降低肠黏膜通透性,其效果与添加3 000 mg/kg锌(氧化锌)相当。     

水解单宁酸替代部分氧化锌在断奶仔猪中预防腹泻的应用及对生长性能的影响

探讨从五倍子中提取的50%水解单宁酸,作为饲料添加剂部分替代氧化锌对断奶仔猪腹泻的预防作用及对仔猪生长性能的影响。将45头(28±1)日龄断奶的仔猪随机分为3组。基础日粮相同,I组为对照组,加入2kg/t氧化锌(含量75%),Ⅱ和Ⅲ组为试验组,分别加入1kg/t氧化锌(含量75%)+1kg/t水解单宁酸(含量50%)和2kg氧化锌(含量75%)+1kg/t水解单宁酸(含量50%),试验期14天。结果表明,在腹泻率方面,Ⅰ组为3.81%,Ⅱ组和Ⅲ组都为1.90%,与Ⅰ组相比降低了50%。试验组与对照组组间差异显著(P<0.05)。在日增重方面,Ⅱ组和Ⅲ组比Ⅰ组分别提高11.3%和13.0%。在料重比方面,Ⅱ组和Ⅲ组比Ⅰ组分别下降0.14(P<0.05)和0.07(P> 0.05)。试验结果说明使用水解单宁酸为主要成分的植物提取物,在降低氧化锌使用量的同时,还可提高日增重,降低料重比和腹泻率。     

不同形式氧化锌对断奶仔猪生长性能及腹泻的影响

选用24~26日龄"长×大"二元杂交断奶仔猪96头(平均体重6.84 kg±0.16 kg),研究不同形式氧化锌对断奶仔猪生长性能和腹泻的影响。试验仔猪按完全随机区组设计分为4组,每组3个重复,每个重复8头仔猪。对照组饲喂基础日粮,试验1、2、3组分别在基础日粮中添加2800 g/t普通氧化锌、800 g/t包膜氧化锌、500 g/t纳米氧化锌,试验期14 d。结果表明,与对照组相比,试验1、2、3组断奶仔猪平均日增重分别提高了15.26%(P<0.05)、9.88%(P<0.05)和14.69%(P<0.05),料重比降低了9.59%(P<0.05)、7.53%(P<0.05)和10.27%(P<0.05);腹泻率降低了66.67%(P<0.05)、55.55%(P<0.05)和55.55%(P<0.05)。试验1、2、3组之间断奶仔猪的平均日增重、料重比及腹泻率均无显著差异(P>0.05),说明包膜氧化锌和纳米氧化锌是一种代替高剂量普通氧化锌的可行选择。     

丁酸甘油酯对断奶仔猪生长性能和腹泻率影响的Meta分析

研究旨在探讨丁酸甘油酯对断奶仔猪生长性能和腹泻率的影响,运用Meta分析方法进行系统评价。经检索万方、中国知网、维普、Pub Med和Web of Science数据库,搜索丁酸甘油酯对断奶仔猪生长性能影响的文献,按照纳入和排除标准筛选文献、提取资料,用Review Manager 5.4软件进行Meta分析。共纳入12个研究,样本838例。结果显示：丁酸甘油酯组的平均日增重显著高于空白组（P<0.000 1,SMD=1.58,95%CI:0.80～2.36）,平均日采食量与空白组差异不显著（P=0.30,SMD=-0.44,95%CI:-1.28～0.40）,料重比显著低于空白组（P=0.000 2,SMD=-0.85,95%CI:-1.29～-0.40）,腹泻率显著低于空白组（P=0.000 3,SMD=-2.78, 95%CI:-4.27～-1.28）。说明饲料中添加丁酸甘油酯可显著提高断奶仔猪的平均日增重,降低料重比和腹泻率,建议丁酸甘油酯添加量为1%～2%。     

浅谈高水平的氧化锌对断奶仔猪各方面的影响

锌是体内40多种金属酶的组成成分,200多种酶的激活因子,参与核酸和蛋白质合成、能量代谢、氧化还原、细胞免疫和体液免疫过程。而高锌主要用在幼龄畜禽日粮中,国内外有大量报道,早期断奶仔猪日粮中添加高锌能减少仔猪腹泻,改善生长性能,提高日增重,改善饲料报酬,本文就此做一综述。     

Effect of phosphorylated mannans and pharmacological additions of zinc oxide on growth and immunocompetence of weanling pigs

Three experiments were conducted to evaluate the efficacy of phosphorylated mannans (MAN) and pharmacological levels of ZnO on performance and immunity when added to nursery pig diets. Pigs (216 in each experiment), averaging 19 d of age and 6.2, 4.6, and 5.6 kg of BW in Exp. 1, 2, and 3, respectively, were blocked by BW in each experiment, and penned in groups of six. A lymphocyte blastogenesis assay was performed in each experiment to measure in vitro lymphocyte proliferation response. In Exp. 1, diets were arranged as a 2 x 2 factorial with two levels of Zn (200 and 2,500 ppm) and two levels of MAN (0 and 0.3% from d 0 to 10, and 0 and 0.2% from d 10 to 38). Zinc oxide increased (P < 0.05) ADG, ADFI, and G:F from d 0 to 10, and ADG and ADFI from d 10 to 24. In Exp. 2, diets were arranged as a 2 x 3 factorial with two levels of Zn (200 and 2,500 ppm) and three levels of MAN (0, 0.2, and 0.3%). Pigs fed 2,500 ppm Zn from d 0 to 10 had greater (P < 0.05) ADG, ADFI, and G:F than pigs fed 200 ppm Zn. From d 10 to 24, ADG was similar when pigs were fed 200 ppm Zn, regardless of MAN supplementation; however, ADG increased (P < 0.05) when 0.2% MAN was added to dietscontaining 2,500 ppm Zn (MAN x Zn interaction, P < 0.05). In Exp. 3, diets were arranged as a 2 x 3 factorial with two levels of MAN (0 and 0.3%) and three levels of Zn (200, 500, and 2,500 ppm). Zinc was maintained at 200 ppm from d 21 to 35, so only two dietary treatments (0 and 0.3% MAN) were fed during this period. Average daily gain was greater (P < 0.05) from d 7 to 21 when pigs were fed 2,500 ppm Zn compared with pigs fed 200 or 500 ppm Zn. The addition of MAN improved (P < 0.05) G:F from d 7 to 21 and d 0 to 35. Lymphocyte proliferation of unstimulated cells and phytohemagglutinin-stimulated cells was decreased (P < 0.05) in cells isolated from pigs fed MAN compared with cells isolated from pigs fed diets without MAN. Lymphocyte proliferation of pokeweed mitogen-stimulated cells isolated from pigs fed MAN was less (P < 0.05) than for pigs fed diets devoid of MAN when diets contained 200 ppm Zn; however, MAN had no effect on lymphocyte proliferation when the diet contained 500 or 2,500 ppm Zn (MAN x Zn interaction, P < 0.05). Although the magnitude of response to MAN was not equivalent to that of pharmacological concentrations of Zn, MAN mayimprove growth response when pharmacological Zn levels are restricted.     

Effect of mannan oligosaccharides on growth performance of weanling pigs

Four experiments were conducted to evaluate the effects of mannan oligosaccharides (provided by Bio-Mos [BM], a product containing a minimum of 28% glucomannoprotein from S. cerevisiae) on growth performance of nursery pigs. Treatments were replicated with five to six pens of four to five pigs each. Initial BW ranged from 4.7 to 5.4 kg, and pigs were weaned at 16 to 20 d of age. Experiments 1, 2, and 4 consisted of Phase 1 (7 to 8 d), Phase 2 (12 to 14 d), and Phase 3 (7 to 8 d) periods, but Exp. 3 consisted only of Phase 1 (7 d) and 2 (14 d) periods. The diets for Phase 1, 2, and 3 contained 1.6, 1.5, and 1.1% Lys, respectively. The treatments in Exp. 1 were 0, 0.20, and 0.30% BM, which did not affect growth performance. The treatments in Exp. 2 were two levels of excess Zn (0 and 3,000 ppm) and three levels of BM (0, 0.20, and 0.30%) in a 2 x 3 factorial. Excess Zn increased (P < 0.08) ADG and ADFI in Phase 2 and 3 and overall. The 0.20% BM addition increased ADG (Phase 3 and overall) and ADFI (Phase 2 and overall) in the absence of excess Zn but did not affect or decreased these response variables in the presence of excess Zn (Zn x BM quadratic, P < 0.08). Experiment 3 was similar to Exp. 2, but the 0.30% BM addition was not used. Excess Zn decreased (P < 0.09) ADG in Phase 1 but increased (P < 0.09) ADG and ADFI in Phase 2. The BM decreased (P < 0.03) overall ADFI but increased Phase 2 and overall ADG and gain:feed (GF) in the absence of excess Zn but not in the presence of excess Zn (Zn x BM, P < 0.07). The BM decreased ADFI during Phase 2, but the decrease was greater in pigs fed excess Zn (Zn x BM, P < 0.07). Experiment 4 evaluated the interactive effects of the antibiotic (oxytetracycline and neomycin) and BM and of Zn and BM. Antibiotic (no excess Zn) increased (P < 0.01) ADG and ADFI in Phases 2 and 3 and overall. The BM addition decreased ADG and GF in Phase 2 when the antibiotic was not in the diet but increased ADG when the antibiotic was in the diet (antibiotic x BM, P < 0.05). Excess Zn increased (P < 0.07) ADG and ADFI during Phases 2 and 3 and overall. In Phase 2, the 0.20% BM decreased GF when excess Zn was not added to the diet but increased GF when Zn was included (Zn x BM, P < 0.03). Mannan oligosaccharides improved pig performance in some instances during Phase 2 when fed in combination with an antibiotic and no excess dietary Zn, but it had no effect or negative effects in the presence of excess Zn or in the absence of an antibiotic.     

Comparison of growth performance and zinc absorption, retention, and excretion in weanling pigs fed diets supplemented with zinc-polysaccharide or zinc oxide

Fifty weanling crossbred pigs averaging 6.2 kg of initial BW and 21 d of age were used in a 5-wk experiment to evaluate lower dietary concentrations of an organic source of Zn as a Zn-polysaccharide (Zn-PS) compared with 2,000 ppm of inorganic Zn as ZnO, with growth performance, plasma concentrations of Zn and Cu, and Zn and Cu balance as the criteria. The pigs were fed individually in metabolism crates, and Zn and Cu balance were measured on individual pigs (10 replications per treatment) from d 22 to 26. The basal Phase 1 (d 0 to 14) and Phase 2 (d 14 to 35) diets contained 125 or 100 ppm added Zn as Zn sulfate, respectively, and met all nutrient requirements. Treatments were the basal Phase 1 and 2 diets supplemented with 0, 150, 300, or 450 ppm of Zn as Zn-PS or 2,000 ppm Zn as ZnO. Blood samples were collected from all pigs on d 7, 14, and 28. For pigs fed increasing Zn as Zn-PS, there were no linear or quadratic responses (P > or = 0.16) in ADG, ADFI, or G:F for Phases 1 or 2 or overall. For single degree of freedom treatment comparisons, Phase 1 ADG and G:F were greater (P < or = 0.05) for pigs fed 2,000 ppm Zn as ZnO than for pigs fed the control diet or the diet containing 150 ppm Zn as Zn-PS. For Phase 2 and overall, ADG and G:F for pigs fed the diets containing 300 or 450 ppm of Zn as Zn-PS did not differ (P > or = 0.29) from pigs fed the diet containing ZnO. Pigs fed the diet containing ZnO also had a greater Phase 2 (P < or = 0.10) and overall (P < or = 0.05) ADG and G:F than pigs fed the control diet. There were no differences (P > or = 0.46) in ADFI for any planned comparison. There were linear increases (P < 0.001) in the Zn excreted (mg/d) with increasing dietary Zn-PS. Pigs fed the diet containing ZnO absorbed, retained, and excreted more Zn (P < 0.001) than pigs fed the control diet or any of the diets containing Zn-PS. In conclusion, Phase 2 and overall growth performance by pigs fed diets containing 300 or 450 ppm Zn as Zn-PS did not differ from that of pigs fed 2,000 ppm Zn as ZnO; however, feeding 300 ppm Zn as Zn-PS decreased Zn excretion by 76% compared with feeding 2,000 ppm Zn as ZnO.     

功能性低聚糖对断奶仔猪腹泻的防治及生产性能的影响

在仔猪饲粮中分别添加低聚果糖(FOS)、异麦芽低聚糖(GOS)和甘露寡糖(MOS),用48头35日龄杜×长断奶仔猪进行了为期28 d的饲养试验,观察了功能性低聚糖对断奶仔猪腹泻的防治作用及生产性能的影响.将试验猪随机分为4组,即在基础日粮中分别添加FOS 3 g/kg、GOS 2 g/kg和MOS 3 g/kg的3个处理组和1个对照组,观察了仔猪的生长发育情况,记录了各组耗料量和体重,采集血清和全血以及粪样进行了分析测试.结果表明,FOS组仔猪腹泻频率降低了66%;GOS组降低了25%;MOS组降低了54%;FOS、GOS和MOS组的血清SOD、GSH-Px活性均较对照组显著提高(P＜0.05或P＜0.01);3种低聚糖组仔猪的外周血T淋巴细胞数(CD3)、IgG水平均较对照组显著提高(P＜0.05或P＜0.01);3种低聚糖组仔猪的日增重和饲料报酬均有明显的提高.     

发酵乳清粉对断奶仔猪生产性能、腹泻率和消化能力的影响

<正>乳清粉是乳品工业的副产物,含有丰富的营养物质,可向动物尤其是幼龄动物提供丰富的营养素。同时,乳清粉又是一种很容易消化吸收的物质,非常适合刚断奶这一特殊生理阶段的仔猪。目前,在断奶仔猪饲料中乳清粉已被普遍使用。     

Effect of sodium butyrate on growth performance and response to lipopolysaccharide in weanling pigs

Two experiments were conducted to determine the effects of dietary sodium butyrate on growth performance and response to Escherichia coli lipopolysaccharide (LPS) in weanling pigs. In a 28-d experiment, 180 pigs (initial BW 6.3 kg) were fed 0, 0.05, 0.1, 0.2, or 0.4% sodium butyrate, or 110 mg/kg of dietary tylosin. There was no effect of dietary sodium butyrate or tylosin on overall G:F, but there was a linear trend (P < 0.07) toward decreased ADFI and ADG as levels of sodium butyrate increased. In a second 28-d experiment, 108 pigs (initial BW 6.3 kg) were assigned to 1 of 3 dietary treatments: 1) no antibiotics, 2) 0.2% sodium butyrate, or 3) 55 mg/kg of carbadox. On d 14, a subset of pigs from the no-antibiotic and butyrate treatment groups was challenged with E. coli LPS or injected with sterile saline in a 2 x 2 factorial arrangement (+/-LPS challenge; +/-dietary butyrate; n = 6 pigs/treatment group). Four hours after LPS challenge, blood samples were obtained, and samples of LM, liver, and ileum were collected for gene expression analysis. Serum samples were analyzed for IL-6, tumor necrosis factor alpha (TNFalpha), alpha(1)-acid glycoprotein, cortisol, IGF-I, insulin, and metabolites. The relative abundance of tissue cytokine and IGF-I mRNA was measured by real-time PCR. Feeding diets containing sodium butyrate or carbadox did not alter ADG or ADFI compared with pigs fed the control diet. From d 0 to 14, pigs fed diets containing 0.2% sodium butyrate had decreased (P < 0.05) ADG and tended (P < 0.06) to have decreased G:F compared with animals fed diets containing carbadox. Challenge with LPS increased (P < 0.05) serum cytokines and cortisol and decreased (P < 0.05) serum glucose and triglycerides. Injection with LPS increased (P < 0.05) the relative abundance of hepatic IL-6 and TNFalpha mRNA, increased (P < 0.05) LM TNFalpha mRNA content, and decreased (P < 0.05) IGF-I mRNA in LM. For serum cortisol, there was an interaction (P < 0.05) between dietary butyrate and LPS. The increase in serum cortisol attributable to LPS was greater (P < 0.05) in pigs fed butyrate than in pigs fed the control diet. There tended (P < 0.10) to be an interaction between LPS and diet and for butyrate to increase the relative abundance of IL-6 mRNA in LM. Carbadox did not alter cytokine or IGF-I mRNA or serum metabolites, but did decrease (P < 0.05) serum TNFalpha. These data indicate that dietary sodium butyrate does not enhance growth performance, but may regulate the response to inflammatory stimuli in weanling pigs.     

Effect of mannan oligosaccharides and fructan on growth performance, nutrient digestibility, blood profile, and diarrhea score in weanling pigs

A total of 150 weanling pigs [(Yorkshire × Landrace) × Duroc] with an average BW of 7.22 ± 0.80 kg (21 d of age) were used in a 28-d trial to determine the effects of dietary fructan and mannan oligosaccharides on growth performance, nutrient digestibility, blood profile, and diarrhea score in weanling pigs. Pigs were allotted randomly to 1 of 5 dietary treatments: 1) negative control (NC), basal diet; 2) positive control (PC), NC + 0.01% apramycin (165 mg/kg); 3) NC + 0.1% fructan (FC); 4) NC + 0.1% mannan oligosaccharide source (MO); and 5) NC + 0.05% fructan + 0.05% mannan oligosaccharide source (FM). There were 3 replications per treatment with 10 pigs per pen (5 barrows and 5 gilts). From d 0 to 14, ADG and ADFI of pigs fed the PC, MO, and FM diets were greater (P < 0.05) than pigs fed the NC diet. From d 15 to 28, there were no differences (P > 0.05) in ADG, ADFI, and G:F. During the overall period (d 0 to 28), pigs fed the MO diet had a greater ADG than pigs fed the NC diet (P < 0.05). Pigs fed the PC and MO diets increased ADFI (P < 0.05) compared with pigs fed the NC diet. However, no differences were detected among dietary treatments in G:F during the overall experimental period. On d 14, the apparent total tract digestibility (ATTD) of DM and N in pigs fed the PC, MO, and FM diets was greater (P < 0.05) than pigs fed the NC diet. The ATTD of DM increased (P < 0.05) in pigs fed the MO and FM diets compared with pigs fed the FC diet. However, at the end of the experiment, pigs fed the FM diet had a greater (P < 0.05) ATTD of DM compared with pigs fed the NC diet. Additionally, there were no differences in IgG, red blood cells, white blood cells, and lymphocyte counts among dietary treatments on d 0, 14, or 28. The diarrhea score in pigs fed the MO diet was reduced (P < 0.05) compared with pigs fed the NC diet. In conclusion, mannan oligosaccharides have a beneficial effect on growth performance and nutrient digestibility in weanling pigs. Furthermore, mannan oligosaccharides can decrease diarrhea score in weanling pigs.     

Effects of supplemental dietary phytase and pharmacological concentrations of zinc on growth performance and tissue zinc concentrations of weanling pigs

Three experiments were conducted to determine the effects of phytase, excess Zn, or their combination in diets for nursery pigs. In all experiments, treatments were replicated with five to seven pens of six to seven pigs per pen, dietary Ca and available P (aP) levels were decreased by 0.1% when phytase was added to the diets, excess Zn was added as ZnO, a basal level of 127 mg/kg of Zn (Zn sulfate) was present in all diets, and the experimental periods were 19 to 21 d. In Exp. 1, pigs (5.7 kg and 18 d of age) were fed two levels of phytase (0 or 500 phytase units/kg) and three levels of excess Zn (0, 1,000, or 2,000 ppm) in a 2 x 3 factorial arrangement. Added Zn linearly increased ADG and ADFI during Phase 1 (P = 0.01 to 0.06), Phase 2 (P = 0.02 to 0.09), and overall (P = 0.01 to 0.02). Gain:feed was linearly increased by Zn during Phase 1 (P = 0.01) but not at other times. Dietary phytase decreased ADG in pigs fed 1,000 or 2,000 ppm Zn during Phase 2 (Zn linear x phytase interaction; P = 0.10), did not affect (P = 0.27 to 0.62) ADFI during any period, and decreased G:F during Phase 2 (P = 0.01) and for the overall (P = 0.07) period. Plasma Zn was increased by supplemental Zn (Zn quadratic, P = 0.01) but not affected (P = 0.70) by phytase addition. In Exp. 2, pigs (5.2 kg and 18 d of age) were fed two levels of phytase (0 or 500 phytase units/kg) and two levels of Zn (0 or 2,000 ppm) in a 2 x 2 factorial arrangement. Supplemental Zn increased ADG and G:F during Phase 2 (P = 0.02 to 0.09) and overall (P = 0.07 to 0.08), but it had no effect (P = 0.11 to 0.89) on ADG during Phase 1 or ADFI during any period. Phytase supplementation increased ADG (P = 0.06) and G:F (P = 0.01) during Phase 2. Gain:feed was greatest for pigs fed 2,000 ppm Zn and phytase (Zn x phytase interaction; P = 0.01). Bone (d 20) and plasma Zn (d 7 and 20) were increased (P = 0.01) by added Zn but not affected (P = 0.51 to 0.90) by phytase. In Exp. 3, pigs (5.7 kg and 19 d of age) were fed a basal diet or the basal diet with Ca and aP levels decreased by 0.10% and these two diets with or without 500 phytase units/kg. Supplemental phytase had no effect (P = 0.21 to 0.81) on growth performance. Reduction of dietary Ca and aP decreased (P = 0.02 to 0.08) ADG, ADFI, and G:F for the overall data. These results indicate that excess dietary supplemental Zn increases ADG and plasma and bone Zn concentrations. Dietary phytase did not affect plasma or bone Zn concentrations.