不同磷水平饲粮添加植酸酶对猪生长性能及磷和钙代谢影响的研究

为探讨不同磷水平饲粮添加植酸酶对猪生长性能及磷、钙代谢的影响,选择健康、体重均匀且平均体重约41 kg的40头杜长大三元杂种生长猪,根据体重和性别分成4组,每组10头、公母各半,设10个重复,每个重复1头猪,分生长（41~60 kg）和肥育（60~90 kg）两个阶段饲养：对照组饲粮分别含总磷0.55%和0.50%、有效磷0.28%和0.24%;低磷加酶1组饲粮分别含总磷0.50%和0.47%、有效磷0.23%和0.21%,添加植酸酶750 FTU/kg饲粮;低磷加酶2组饲粮分别含总磷0.45%和0.44%、有效磷0.18%和0.18%,添加植酸酶750 FTU/kg饲粮;低磷加酶3组饲粮分别含总磷0.40%和0.40%、有效磷0.13%和0.14%,添加植酸酶750 FTU/kg饲粮。预试期7 d,正试期66 d。结果表明：①生长性能,试验全期,与对照组相比,低磷加酶1组、2组和3组日增重都有一定程度的提高（P〉0.05）,料重比分别降低4.81%（P〉0.05）、8.65%（P〉0.05）和13.14%（P〈0.05）。②血清生化指标,肥育阶段,血清钙含量低磷加酶1组、3组与对照组均差异显著（P〈0.05）,血清磷含量、碱性磷酸酶活性各组差异均不显著（P〉0.05）。③磷、钙排泄量,生长阶段,与对照组相比,低磷加酶1组、2组和3组磷排泄量降低19.06%~26.09%（P〈0.01）,钙排泄量均有一定程度的提高;肥育阶段,与对照组相比,低磷加酶2组和3组磷排泄量分别降低29.70%（P〈0.01）和31.68%（P〈0.01）,低磷加酶1组、2组和3组钙排泄量分别降低2.13%（P〉0.05）、30.18%（P〈0.01）和28.96%（P〈0.01）。综上所述,生长肥育猪饲粮无机磷（磷酸氢钙）添加水平降低,直至全部不加,在添加植酸酶（750 FTU/kg饲粮）的条件下,生长性能没有降低,日增重和饲料转化率有提高的趋势,磷排泄量显著降低。     

添加了植酸酶的生长肥育猪饲粮中粗蛋白质和磷水平对其钙磷代谢的影响

降低饲粮中粗蛋白质含量（CP）添加氨基酸可以减少猪氮的排泄量（O＇Shea et al.,2009）。降低饲粮磷含量添加植酸酶可以减少磷的排泄量（Sands et al.,2001）。但是,重要的是研究饲粮粗蛋白质和磷的交互作用对氮和矿物质利用率的影响,因为,     

日粮添加植酸酶及不同钙磷水平对生长肥育猪生长性能的影响

利用饲养试验和代谢试验方法,研究玉米-豆粕型日粮中添加植酸酶时不同磷水平和钙磷比对生长肥育猪生产性能的影响。试验选用162头20kg左右的杜长大三元杂交猪进行2×3(磷水平×钙磷比)因子饲养试验,研究磷水平、钙磷比对猪生产性能的影响及磷水平×钙磷比互作效应,试验分2个阶段进行,前期为生长期体重为20~60kg,后期为肥育期体重为为60~100kg。将试验猪随机分配到6个处理中,每个处理设3个重复(3个栏),每个重复9头猪,公母各半。日粮磷水平在前期为0.4%和0.5%,后期为0.3%和0.4%;钙磷比例全程均为1∶1、1.3∶1和1.6∶1。试验基础日粮由玉米、豆粕、鱼粉、米糠组成,预混料中添加了植酸酶(活性为5000U,添加量为100g/d)。结果表明添加植酸酶日粮磷水平和钙磷比对猪生长期和肥育期的平均日增重和料重比无显著影响(P>0.05)。     

饲粮中植酸磷水平对生长肥育猪生产性能及植酸磷利用率的影响

24头长白猪(70日龄),随机等分为4组,喂以在玉米淀粉—豆饼为主的基础饲粮中添加不同量植酸钠组成植酸磷水平分别为0.065％、0.15％、0.25％、0.35％(占总磷水平分别为13％、30％、50％、70％)的4种饲粮,试验为期5周,研究饲粮中植酸磷水平对生长猪生产性能的影响。饲养试验结束后,从Ⅰ、Ⅲ、Ⅳ组各选3头公猪饲喂于木制代谢笼中,为期6天,进行全收粪法的代谢试验,研究生长肥育猪对植酸磷的利用率及与饲粮中植酸磷水平的关系。结果表明:1)随着饲粮中植酸磷水平升高,猪的日增重降低,植酸磷水平达0.35％时则极显著降低日增重和饲粮转化率(P<0.01)。2)生长猪对植酸磷的利用率为33％—36％,总磷的利用率40—60％,且与饲粮中植酸磷水平显著相关,相关系数分别为0.95(P<0.05),-0.87(P<0.05)。     

在生长肥育猪低蛋白质饲粮中添加赖氨酸和苏氨酸的效果试验

选择体重30kg左右的杜长大三元杂种猪48头,随机分为4组,每组12头(母猪5头,阉公猪7头),随机接受4种饲粮处理,进行为期88天肥育对比试验。试验饲粮为玉米-豆粕型,各组消化能约13MJ/kg,对照1组蛋白质水平生长期16.42%、肥育期14.76%,对照2组、试验1组、试验2组基础饲粮配方相同,均为蛋白质水平比对照1组降低3个百分点(生长期13.58%、肥育期11.70%)而添加0.2%赖氨酸,试验1组、试验2组又添加0.1%和0.05%苏氨酸。结果,试验1组和试验2组与对照1组相比,生长期日增重分别提高2.0%(P>0.05)和1.5%(P>0.05),料重比略提高或相同;肥育期日增重分别提高/降低2.2%(P>0.05)和0.4%(P>0.05),料重比相近;全期日增重分别提高2.2%(P>0.05)和0.6%(P>0.05),料重比相近;全期饲料成本降低4%左右。对照2组与试验1组、试验2组及对照1组比较,生长期、肥育期、全期日增重最低,且均差异显著,料重比最高。表明,在生长肥育猪的低蛋白质饲粮中添加赖氨酸和苏氨酸不影响其日增重、料重比,可降低饲料成本左右。     

生长肥育猪饲粮中适宜粗纤维水平的研究

通过调节玉米、苜蓿草粉的添加量控制饲粮粗纤维水平,以５％、７％、９％三个粗纤维水平的饲粮饲喂生长肥育猪,试猪体重在２０ｋｇ～３５ｋｇ、３５ｋｇ～６０ｋｇ、６０ｋｇ～９０ｋｇ以及整个２０ｋｇ～９０ｋｇ体重阶段,生长表现组间无显著差异（Ｐ＞０．０５）,表观值,２０ｋｇ～３５ｋｇ阶段５％水平最佳;３５ｋｇ～６０ｋｇ阶段７％与５％水平接近;６０ｋｇ～９０ｋｇ阶段,７％水平最佳。整个２０ｋｇ～９０ｋｇ生长肥育阶段,７％水平最佳,５％水平与其接近,９％水平最差,７％水平经济效益最佳。     

添加植酸酶降低钙磷比可提高生长肥育猪对磷的利用

在以玉米豆粕为基础的猪禽日粮中,大量以植酸形式存在的磷无法被动物有效地吸收利用,导致这一丰富的磷资源大量浪费,而另一方面为了提供动物必需的而常规饲料无法满足的磷的营养需要,又不得不额外添加昂贵的无机磷。因此,围绕植酸磷的转化利用,提高饲料总磷的可消化...     

低磷饲粮中添加粗制植酸酶对产蛋后期蛋鸡生产的影响

选用180只70周龄的罗曼蛋鸡随机分成3组,以含0.4%非植酸磷基础饲粮组为对照组、在含0.1%非植酸磷饲粮中分别添加0.5%和0.0%粗制植酸酶饲粮构成试验Ⅰ组和试验Ⅱ组,研究低磷蛋鸡饲粮中添加粗制植酸酶对产蛋后期蛋鸡生产性能、蛋壳品质、血液生化指标和养分表观存留率的影响,并对其经济效益做初步评价。结果表明:综合试验蛋鸡的各项生产性能表现,在含0.1%非植酸磷蛋鸡饲粮中添加0.5%的粗制植酸酶,可获得与对照组相近的饲养效果,而未添加粗制植酸酶的低磷饲粮组蛋鸡生产性能则明显降低。由此可知,非植酸磷为0.1%的蛋鸡饲粮中添加0.5%粗制植酸酶对蛋鸡的各项生产指标、鸡蛋壳品质及血液生化指标未造成不良影响,并能增加养殖蛋鸡的经济收入,降低排泄物中磷对环境的污染。     

饲粮中添加植酸酶对生长肥育猪矿物元素利用和排泄的影响

选用60头平均体重28.3 kg的杜洛克×长白×大约克夏三元杂交猪,随机分成2组,每组30头,研究在饲粮中添加植酸酶(750 FTU/kg)对生长肥育猪矿物元素利用和排泄的影响。结果表明:1)添加植酸酶使生长猪对铜和锌的消化率、肥育猪对粗灰分、磷、铜和锌的消化率显著提高(P<0.05或P<0.01)。2)添加植酸酶使生长猪对铜和锌的吸收量、肥育猪对粗灰分、磷、铜和锌的吸收量显著提高(P<0.05或P<0.01)。3)添加植酸酶显著降低生长猪粪中铜、肥育猪粪中粗灰分和磷的排泄量(P<0.05)。     

低蛋白饲粮添加植酸酶和非淀粉多糖酶对生长猪生长性能和养分排泄量的影响

试验旨在研究低蛋白质饲粮添加植酸酶和非淀粉多糖(NSP)酶对生长猪生长性能、养分排泄量的影响。54头平均初始体重为(41.92±2.6)kg的杜长大三元杂交猪分为3组,每组3个重复,每个重复6头猪。1组为对照组(饲粮粗蛋白质水平为17.4%),2、3组为试验组,2组在1组基础上,饲粮粗蛋白质水平降至14.3%、总磷水平降低0.1个百分点,添加植酸酶;3组在2组基础上添加NSP酶,试验期38 d。试验结果表明,2组的平均日增重、料重比比1组分别提高7.64%和1.94%(P0.05),其余各组间差异不显著(P0.05);粪N浓度2、3组比1组分别降低18.58%、23.01%(P0.05);粪P浓度2、3组比1组分别降低40.23%、39.08%(P0.01)。由此可见,将常规饲粮粗蛋白质水平降低3个百分点、总磷水平降低0.1个百分点,并添加植酸酶,能显著提高生长猪平均日增重,显著减少粪氮含量,极显著减少粪磷含量;在此基础上,继续添加NSP酶不影响生长猪生长性能和粪中养分含量。     

生长猪低磷日粮添加植酸酶和有机酸以及维生素D_3的研究

本试验通过添加植酸酶、有机酸(柠檬酸、抗坏血酸)和维生素D3、木聚糖酶来减少无机磷的添加量,提高饲料中植酸磷的利用率,降低磷的排泄量。选择30 kg左右的"斯格"纯种猪70头,随机分成7组:常磷组、低磷日粮组(NC)、NC+600 U/kg植酸酶组、NC+600 U/kg植酸酶+10 g/kg的柠檬酸、NC+600 U/kg植酸酶+10 g/kg的柠檬酸+200 mg/kg抗坏血酸、NC+600 U/kg植酸酶+10 g/kg的柠檬酸+200 mg/kg抗坏血酸+100μg/kg的维生素D3、不添加磷酸氢钙。所有日粮中都添加50 mg/kg木聚糖酶。结果表明:低磷日粮添加植酸酶、有机酸(柠檬酸、抗坏血酸)和维生素D3,平均日采食量无显著影响(P0.05),日增重显著提高(P0.05),料重比显著降低(P0.05);养分消化率均显著提高;血液指标着中,白蛋白显著降低(P0.05),碱性磷酸酶、总蛋白、谷草、谷丙转氨酶无影响(P0.05)。     

耐热植酸酶在低钙磷饲粮中添加对仔猪和生长猪的饲用效果研究

为确认经基因工程改造以酵母发酵生产的植酸酶的耐热性及其在肉猪饲粮中的应用效果,本试验结合颗粒饲料生产实际条件检测植酸酶样的耐热性,并以仔猪和生长猪为对象开展饲养试验.以玉米725.00 kg、豆粕203.24 kg、统糠11.26 kg、次粉15.00kg、大豆油15.00 kg和植酸酶30.50kg(5000 U/g)组成混合料,经调质温度为85℃和调质时间为30 s的生产线制粒,分别抽取调质前、调质后和制粒后等3个处理阶段各5个点样,测定各样的植酸酶活量,分别计算出植酸酶在调质前、调质后和制粒后的酶活回收率(%).饲养试验一:90头杜长大仔猪(9.86±0.09)kg随机分为3个处理,每个处理3个重复,每个重复10头;3组分别饲喂3种等蛋白质等能量等钙磷比的玉米-豆粕型试验饲粮(20.0%、13.39 MJ/kg和1.26),为期4周;正对照饲粮含钙0.82%和磷0.65%,负对照饲粮含钙0.62%和磷0.49%,植酸酶饲粮为在负对照饲粮基础上添加植酸酶的饲粮(500 U/kg).饲养试验二:60头杜长大生长猪(22.45±0.67)kg随机分为2个处理,每个处理3个重复,每个重复10头;2组分别饲喂2种等蛋白质等能量等钙磷比的生长猪试验饲粮(17.5%、13.00 MJ/kg和1.0),为期4周;对照饲粮含钙0.66%和磷0.67%,植酸酶饲粮含钙0.56%、磷0.56%和植酸酶(500 U/kg).试验结果表明:(1)调质前、调质后和颗粒产品样的酶活回收率分别为104.8%、73.2%和68.2%(P＜0.05);(2)饲养试验一中的植酸酶组仔猪生产性能与正对照组的差异不显著(P＞0.05),但负对照的增重和耗料增重比分别显著低和高于正对照的(P＜0.05);(3)饲养试验二中的植酸酶组生长猪的耗料量较对照组的降低了9%,耗料增重比降低了11%(P＜0.05).增重提高了2%.此酶样经颗粒料生产全程工序后仍具68.2%的存酶活,具较好的耐热性;在低磷饲粮中应用可提高饲料转化率,因而提高仔猪及生长猪的增重,并降低饲料成本.     

Ileal amino acid and phosphorus digestibility responses of pigs to microbial phytase supplementation of high-phytin diets

The hypothesis that increase in dietary phytin amplifies phytin binding to protein thereby reducing protein digestion, which is alleviated by phytase, was tested. A 2 × 2 factorial arrangement of dietary treatments was used to investigate the response of growing pigs to supplemental phytase (0, or 1200 units/kg) in low- or high-phytin P diets (2.2 or 3.9 g/kg). Eight crossbred barrows (28–30 kg) were canulated and assigned to crates using a double, 4 × 4 Latin Square design. Pigs were fed each of the 4 diets at 3 times metabolic BW (0.09  BW kg ^0.75) for 7 d. Ileal digesta was collected for 12 h on d 6 and d 7 by attaching plastic bags to the cannula. Feed and ileal digesta were analyzed for N, energy and P. Phytase had no effect on apparent ileal digestibility (AID) of N or AAs. The AID of some AAs was higher in the high-phytin diet, which contradicts the hypothesis that higher phytin content would have a negative impact. In contrast, the AID of P was depressed by high dietary phytin (P < 0.01) and increased by phytase (P < 0.01) more so at the higher dietary phytin resulting in a phytin × phytase interaction (P < 0.01).     

Comparison of Aspergillus niger phytase and Trichoderma reesei phytase and acid phosphatase on phytate phosphorus availability in pigs fed on maize-soybean meal or barley-soybean meal diets.

The efficacy of Aspergillus niger (APhy) phytase, Trichoderma reesei (TPhy) phytase and acid phosphatase (TAcPh) preparations in improving the utilization of phytin-phosphorus in the maize-soybean meal (SBM) or barley-SBM (800:200 g kg-1) diets was studied in two separate digestibility and balance trials with ten growing pigs using 5 x 5 Latin square designs. The positive control diet contained a total phosphorus (P) of 6.5 g kg-1, while the negative control as well as the APhy, TPhy and TAcPh supplemented diets which did not contain additional inorganic-P, had a total P of 4.1 g kg-1. The APhy and TPhy supplements provided phytase activity of 1000 PU g-1 together with AcPh of 8000 HFU g-1. TAcPh at a level of 8000 HFU g-1 was the only addition to one diet. The intrinsic phytase activity of barley was 355 PU g-1 while maize and soybean meal showed no phytase activity. Phytase supplements of the APhy and TPhy sources increased ash digestibility in both diets but had only a minor effect on nitrogen utilization. The addition of phytase improved absorption of P by 21%-units in barley-SBM diet and 29%-units in maize-SBM diet, without any difference between the two phytase sources. The retained P in diets with phytase was higher than in diets without phytase, 4.4 (APhy), 4.5 (TPhy) vs. 2.9 g d-1 in barley-SBM-diets and 3.7 (APhy), 4.0 (TPhy) vs. 1.8 g d-1 in maize-SBM-diets. No difference was found between the two sources of phytase. TAcPh without additional phytase did not show any effect on P absorption or retention. Ca absorption and retention were improved due to the phytase treatments. Supplementing pig diets with either APhy or TPhy sources seems to be equally effective in enhancing the availability of phytate-P. Consequently, these supplements can reduce the P-excretion of pigs by 32-40% as compared with the diet supplemented with inorganic-P.     

Water-soluble phosphorus excretion in pigs fed diets supplemented with microbial phytase

Three experiments were conducted to compare the excretion of water-soluble phosphorus (P) of starter, grower, and finisher pigs fed corn-soybean meal-based P-deficient basal diet containing no added inorganic P (B), P-adequate diet (the basal diet with added dicalcium phosphate; B + P), the basal diet plus 500 units of microbial phytase/kg (B + 500), or the basal diet plus 1000 units of microbial phytase/kg (B + 1000). There were 6 barrows per diet, in a randomized complete block design, with an average initial body weight of 10.4, 20.0, or 51.1 kg for each of starter, grower, and finisher pigs in the three phosphorus balance experiments, respectively. In the experiments, the addition of dicalcium phosphate or phytase to the basal diet increased ( P  < 0.05) the digestibility and retention of P, and there were linear reductions ( P  < 0.05) in water-soluble P excretion as a result of supplementing the basal diet with phytase. In the starter pig experiment, phytase addition at 500 or 1000 units/kg reduced ( P  < 0.05) water-soluble P excretion by 28 or 42%, respectively when compared with the B + P diet. In the grower pig experiment, adding phytase at 500 or 1000 units/kg reduced ( P  < 0.05) water-soluble P excretion by 24 or 34%, respectively when compared with the B + P diet. The use of phytase at 500 or 1000 units/kg reduced ( P  < 0.05) water-soluble P excretion by 11 or 30%, respectively in the finisher pig experiment. The proportion of water-soluble phosphorus in total phosphorus was not affected by dietary treatment in any of the three experiments. In conclusion, adding phytase at 1000 units/kg to a corn-soybean meal-based P-deficient diet basal diet containing no added inorganic P compared with B + P diet reduced the daily excretion of water-soluble P in starter, grower, and finisher pigs by 42, 34, and 30%, respectively.     

生长猪添加植酸酶对植物性蛋白饲料磷消化率的影响研究

采用4个3×3拉丁方设计对12头平均体重(42±5)kg杜×长×大阉猪进行消化试验,在基础日粮中分别添加0,250,500,1000 U/kg的植酸酶,评定植酸酶对菜籽粕、棉籽粕植酸磷和总磷消化率的影响.试验结果表明:(1)菜籽粕、棉籽粕中植酸磷消化率与植酸酶的添加量呈极显著二次曲线关系(P＜0.001).当植酸酶添加量分别为945U/kg和873 U/kg时.菜籽粕、棉籽粕中植酸磷消化率达到最优.(2)菜籽粕、棉籽粕总磷消化率随植酸酶添加量的增加而增加.(3)植酸磷的消化率与总磷表现消化率存在极显著线性关系(P＜0.001).     

Influence of different phosphorus levels and phytase supplementation in gestation diets on sow performance

A total of 104 sows of different parities were studied. They were fed four diets with different phosphorus (P) levels during gestation for two reproductive cycles, while the same diet was fed during lactation. The aim was to decrease the total P level in the diet during gestation and to evaluate the effect on sow performance. The gestation treatments were low P (LP-; 3.7 g P/kg feed), low P with phytase (LP+, Ronozyme P; 765 FTU/kg feed), medium P (MP; 4.5 g P/kg feed) and high P (HP; 6.0 g P/kg feed). Daily feed allowances were 2.6 kg during gestation and 9.2 kg during lactation. Number of born piglets and piglet mortality were higher (p < 0.05) in the LP treatments than in the MP and HP treatments. No difference (p > 0.05) in the numbers of live-born piglets, piglet birthweights, sow weights or piglet weight gains was found between the treatments. Phosphorus level in sow milk was the highest (p < 0.05) in the MP treatment, while no effects (p > 0.05) of treatment were found on milk Ca levels, P and Ca levels in serum of sows and piglets, nor on the analysed mineral, fat and protein contents of piglets. The estimated average requirement of P for the entire gestation period was 4.4-4.5 g/day. In conclusion, a reduction of dietary total P content during gestation did not result in negative effects on sow or piglet performance. This suggests that it should be possible to lower the dietary P content for gestating sows, compared with earlier recommendations, and thereby reduce the environmental P pollution.     

Effect of two microbial phytases on mineral availability and retention and bone mineral density in low-phosphorus diets for broilers

1. The efficacy of supplementation of a low-phosphorus (low-P) maize–soyabean meal diet for broiler chickens with two different microbial (fungal and bacterial) phytases was examined.

2. Broiler chickens received a low-P maize–soyabean meal diet containing either no phytase or one of the two phytases included at one and two times the manufacturer's recommended inclusion level for 21 d.

3. Titanium dioxide was included in the diets as an indigestible marker. Excreta were collected quantitatively from d 18 to 21, and at the end of the study the birds were killed and ileal digesta and leg bone samples collected.

4. No differences were observed for body weight gain and feed intake or apparent metabolisable energy (AME) among all dietary treatment groups.

5. Dietary phytase supplementation improved the apparent retention of Ca, Na and Cu and ileal phytate P absorption from 32% to 44% across inclusion levels.

6. Bone mineral density (BMD) was improved for both phytases across inclusion levels by, on average, 9% for the tibia and 13% for the femur.

7. Dietary phytase supplementation of the low-P diet improved apparent ileal digestibility of serine, glycine, valine, isoleucine, tyrosine, histidine, lysine and arginine.

8. When the results from the present study were combined with the results from other similar published studies and analysed statistically, factors such as dietary P and Ca concentration, as well as bird breed and age, rather than the type or activity of microbial phytase, had the greatest impact on the extent to which dietary supplementation improved P and Ca retention.

9. More work is required to explain the interrelationships between the multiple factors influencing the efficacy of phytase on the availability of dietary minerals.     

低蛋白、低钙磷日粮添加苯甲酸对生长肥猪生长性能及钙磷代谢的影响

文章旨在研究日粮降低粗蛋白质、钙和磷水平,同时添加苯甲酸对仔猪生长性能、钙磷代谢的影响。试验采用2×2多因素试验设计,选择平均体重接近12 kg的保育猪500头,分为4组,每组5个重复,每个重复25头猪。试验日粮共4个,即低水平日粮(低蛋白、低钙磷)组,高水平日粮组(高蛋白、高钙磷),低水平日粮+15 g/kg苯甲酸组,高水平日粮+15 g/kg苯甲酸组。低水平日粮组较高水平日粮组显著降低了仔猪的生长速度(P <0.05),使25 kg阶段仔猪的采食量显著降低了13%(P <0.05)。低水平日粮添加苯甲酸较较高水平日粮组显著降低了25和40 kg猪尿液pH(P <0.05)。低水平组显著降低了钙、磷摄入量及粪中钙磷含量(P <0.05)。日粮添加苯甲酸可以显著降低尿钙排泄量和提高尿磷排泄量(P <0.05)。低水平日粮显著提高了血清钙水平及碱性磷酸酶活性(P <0.05)。低水平日粮组显著降低了血清磷水平(P <0.05),而高水平日粮+苯甲酸组较高水平日粮组显著提高了血清碱性磷酸酶活力和血清磷水平(P <0.05)。日粮添加苯甲酸可以影响磷的消化率,提供仔猪生长早期血清碱性磷酸酶活力,对生长后期猪的骨矿化无显著影响。     

Supplementation of carbohydrases or phytase individually or in combination to diets for weanling and growing-finishing pigs

The overall objective of the studies reported here was to evaluate the growth and nutrient utilization responses of pigs to dietary supplementation of phytate- or nonstarch polysaccharide-degrading enzymes. In Exp. 1, growth performance and nutrient digestibility responses of forty-eight 10-kg pigs to dietary supplementation of phytase or a cocktail of xylanase, amylase, and protease (XAP) alone or in combination were evaluated. The growth response of one hundred fifty 23-kg pigs to dietary supplementation of phytase or xylanase individually or in combination was studied in Exp. 2 in a 6-wk growth trial, whereas Exp. 3 investigated the nutrient digestibility and nutrient retention responses of thirty 24-kg pigs to dietary supplementation of the same enzymes used in Exp. 2. In Exp. 1, the pigs were used in a 28-d feeding trial. They were blocked by BW and sex and allocated to 6 dietary treatments. The treatments were a positive control (PC) diet; a negative control (NC) diet marginally deficient in P and DE; NC with phytase added at 500 or 1,000 phytase units (FTU)/kg; NC with xylanase at 2,500 units (U)/kg, amylase at 400 U/kg, and protease at 4,000 U/kg; and NC with a combination of phytase added at 500 FTU/kg and XAP as above. In Exp. 2 and 3, the 5 dietary treatments were positive control (PC), negative control (NC), NC plus 500 FTU of phytase/kg, NC plus 4,000 U of xylanase/kg, and NC plus phytase and xylanase. In Exp. 1, low levels of nonphytate P and DE in the NC diet depressed (P < 0.05) ADG of the pigs by 16%, but phytase linearly increased (P < 0.05) ADG by up to 24% compared with NC. The cocktail of XAP alone had no effect on ADG of pigs, but the combination of XAP and phytase increased (P < 0.05) ADG by 17% compared with the NC treatment. There was a linear increase (P < 0.01) in Ca and P digestibility in response to phytase. In Exp. 2, ADG was 7% greater in PC than NC (P < 0.05); there were no effects of enzyme addition on any response. In Exp. 3, addition of phytase alone or in combination with xylanase improved (P < 0.05) P digestibility. Phosphorus excretion was greatest (P < 0.01) in the PC and lowest (P < 0.05) in the diet with the combination of phytase and xylanase. The combination of phytase and xylanase improved P retention (P < 0.01) above the NC diet to a level similar to the PC diet. In conclusion, a combination of phytase and carbohydrases improved ADG in 10-kg but not 23-kg pigs, but was efficient in improving P digestibility in pigs of all ages.