植酸酶在养鸡生产中的应用

植酸酶能够降解植物性饲料中的植酸盐类，可以提高动物对饲料中植酸磷的利用率，减少无机磷的添加量，降低成本，并已经开始在畜牧业生产中发挥重要的作用。本文拟从植酸磷的性质，植酸酶的作用机理以及植酸酶在养鸡生产中对磷，锌，铜 利用率的影响作一概述。     

植酸酶对畜禽微量元素利用影响的研究进展

植酸广泛存在于植物性饲料中,在畜禽的消化道内,植酸能与铜、铁、锌、锰等微量元素形成不溶螯合物,植酸酶具有解除植酸的抗营养作用,可破坏植酸对微量元素强烈的亲和力。在畜禽的饲料中加入植酸酶,动物对微量元素的吸收率提高,微量元素的添加量减少,饲料的成本降低,使畜禽微量元素的排泄量减少,减缓了对自然环境的污染。文章综述了植酸的抗营养作用、植酸酶的生物学功能及其对动物微量元素利用的影响。     

植酸酶的研究进展

植酸酶是能降解饲料中植酸及其盐的酶。它能提高磷利用率,解除植酸对一些矿物元素如钙、锌、铁、铜等的抗营养效应,不仅对动物具有良好的增重效果,同时可降低动物排泄磷量,有利于环境保护。植酸酶作为饲料添加剂其作用效果受到饲料中钙、磷水平和钙磷比例以及维生素Ｄ含量的影响。植酸酶的运用需要降低饲料中钙、磷水平,维生素Ｄ与植酸酶之间可能存在协同效应。对植酸酶运用的经济分析表明,使用植酸酶能代替饲料中需添加的无机磷。     

植酸酶与钙的互作效应在畜禽生产中的应用研究进展

植酸酶作为一种饲料添加剂,国内外对其应用效果的研究已取得了很大进展,目前在畜禽饲料中亦已得到了广泛应用,但由于一些研究结果仍具有不确定性,有时甚至相互冲突,使得与植酸酶应用相关的一些问题尚未得到解决,而造成这种结果的原因之一便是日粮钙水平。饲料中的植酸能与钙形成难溶性植酸-钙络合物,不利于钙的吸收利用。添加植酸酶可缓解植酸的抗营养作用,提高饲料中钙的利用率,但高剂量的钙又会对植酸酶的添加效果具有一定的抑制作用。因此,本文就植酸酶和钙的互作效应以及在畜禽生产中的应用作一综述,从而为植酸酶在畜禽生产中更好的推广应用提供理论依据。     

植酸酶在不同反应条件下对大口黑鲈饲料中植酸磷降解率的影响

在大口黑鲈饲料中添加不同水平植酸酶(500、1000、1500U/kg),研究在不同反应时间、温度和pH值条件下饲料中植酸磷的降解率的变化。结果显示,植酸磷的降解率与植酸酶添加量的关系为1500U/kg>1000U/kg>500U/kg。饲料中添加500U/kg植酸酶可分解70%左右的植酸磷,添加1000U/kg植酸酶可分解85%左右的植酸磷,添加1500U/kg植酸酶可分解93%左右的植酸磷。1500和1000U/kg组植酸磷的降解率在催化3h后基本趋于平缓,500U/kg组植酸磷降解率在催化4h后趋于平缓。在20～40℃范围内,植酸磷的降解率随催化温度的升高而增加。在pH值1.5～6.5范围内,植酸磷降解率有两个高峰点,分别出现在pH值为2.5与5.5,在pH值为6.5时,各组饲料中植酸磷的降解率最低。在大口黑鲈饲料中添加植酸酶是可行的。     

植酸酶对肉鸭生长性能和磷利用率的影响

植酸酶(phytases)是一种单磷水解酶.植酸酶具有特殊的空间结构,将植酸(盐)降解为肌醇和无机磷,同时释放出与植酸(盐)结合的其它营养物质,改善饲料中磷的利用率.早期研究表明在植物性饲料原料中,约70％的磷以植酸磷形式存在.在饲料中添加植酸酶不仅可以提高植酸磷的利用率,还能促进饲料中蛋白质的分解和利用,有效提升鸭的...     

降低铜、锌含量添加植酸酶对育肥猪生长性能、养分表观消化率及血清生化指标的影响

本试验旨在探讨植酸水平较高饲料中育肥猪适宜的铜、锌添加水平。试验选取108头55 kg左右的苏姜猪,采用2×3因子设计将试验猪随机分为6组,每组3个重复,每个重复6头。将低、中、高剂量铜、锌与植酸酶添加、不添加组合成6种饲料,每组饲喂其中1种饲料。试验期42 d,测定试验期间育肥猪生长性能、养分表观消化率、血清生化指标及血清和掌骨铜、锌含量。结果显示,降低饲料中铜、锌含量并添加植酸酶未显著影响育肥猪生长性能（P>0.05）。将铜、锌水平从高剂量降低到中、低剂量极显著地提高了铜、锌的表观消化率（P<0.01）,极显著降低了血清铜含量（P<0.01）;从高剂量降低到中剂量极显著降低了血清碱性磷酸酶活性（P<0.01）。添加植酸酶极显著提高了粗蛋白质表观消化率（P<0.01）,显著提高了锌表观消化率和血清碱性磷酸酶活性（P<0.05）。铜、锌水平和添加植酸酶对血清和掌骨锌含量、血清铜蓝蛋白和乳酸脱氢酶活力均无显著影响（P>0.05）。综上所述,在较高植酸水平的饲料中将铜、锌含量降到中等水平可提高铜、锌表观消化率,而不影响生长性能。添加植酸酶有利于提高粗蛋白质、锌的表观消化率。因而建议育肥苏姜猪饲料中添加中剂量铜、锌（即25 mg/kg铜＋40 mg/kg锌）并添加植酸酶。     

家禽日粮中应用植酸酶需考虑的问题

植酸(亦称六磷酸肌醇)广泛存在于植物体内,与磷结合为植酸磷。植酸磷是具有潜在利用价值的磷源,但难以被单胃动物利用。大部分植物性饲料中的磷仅1/3能被家禽有效利用(Carter等,1991),且植酸盐能与不同的阳离子和蛋白质结合,降低了蛋白质及钙、锌、镁和铁等矿物质的生物利用率(Graf,1986),是一种抗营养因子,因此,能催化植酸及植酸盐水解的植酸酶在饲料工业中得到广泛应用。植酸酶包括植物本身的植酸酶和利用微生物产生的外源性植酸酶。1植酸酶在家禽日粮中的应用效果1.1对生产性能的影响许多试验结果表明,添加微生物产生的植酸酶可以改善家…     

家禽日粮中应用植酸酶需考虑的问题

植酸(亦称六磷酸肌醇)广泛存在于植物体内,与磷结合为植酸磷。植酸磷是具有潜在利用价值的磷源,但难以被单胃动物利用。大部分植物性饲料中的磷仅1/3能被家禽有效利用(Carter等,1991),且植酸盐能与不同的阳离子和蛋白质结合,降低了蛋白质及钙、锌、镁和铁等矿物质的生物利用率(Graf,1986),是一种抗营养因子,因此,能催化植酸及植酸盐水解的植酸酶在饲料工业中得到广泛应用。植酸酶包括植物本身的植酸酶和利用微生物产生的外源性植酸酶。1植酸酶在家禽日粮中的应用效果1.1对生产性能的影响许多试验结果表明,添加微生物产生的植酸酶可以改善家…     

降低铜、锌含量添加植酸酶对育肥猪生长性能、养分表观消化率及血清生化指标的影响

本试验旨在探讨植酸水平较高饲料中育肥猪适宜的铜、锌添加水平。试验选取108头55kg左右的苏姜猪,采用2×3因子设计将试验猪随机分为6组,每组3个重复,每个重复6头。将低、中、高剂量铜、锌与植酸酶添加、不添加组合成6种饲料,每组饲喂其中1种饲料。试验期42d,测定试验期间育肥猪生长性能、养分表观消化率、血清生化指标及血清和掌骨铜、锌含量。结果显示,降低饲料中铜、锌含量并添加植酸酶未显著影响育肥猪生长性能(P0.05)。将铜、锌水平从高剂量降低到中、低剂量极显著地提高了铜、锌的表观消化率(P0.01),极显著降低了血清铜含量(P0.01);从高剂量降低到中剂量极显著降低了血清碱性磷酸酶活性(P0.01)。添加植酸酶极显著提高了粗蛋白质表观消化率(P0.01),显著提高了锌表观消化率和血清碱性磷酸酶活性(P0.05)。铜、锌水平和添加植酸酶对血清和掌骨锌含量、血清铜蓝蛋白和乳酸脱氢酶活力均无显著影响(P0.05)。综上所述,在较高植酸水平的饲料中将铜、锌含量降到中等水平可提高铜、锌表观消化率,而不影响生长性能。添加植酸酶有利于提高粗蛋白质、锌的表观消化率。因而建议育肥苏姜猪饲料中添加中剂量铜、锌(即25mg/kg铜+40mg/kg锌)并添加植酸酶。     

Dietary phytase increases the true absorption and endogenous fecal excretion of zinc in growing pigs given a corn-soybean meal based diet

We investigated the effect of dietary phytase on the true absorption and endogenous fecal excretion of zinc (Zn) using ⁶⁷Zn in growing pigs given a corn-soybean meal based diet. Ten crossbred barrows were fed the control diet containing 90-mg/kg Zn, 2.3-g/kg phytate-phosphorus and 3.7-g/kg non-phytate-phosphorus or the phytase diet containing similar amounts of Zn and phytate-phosphorus, and 1.4-g/kg non-phytate-phosphorus with 750-PU/kg phytase for 12 h/day. On day 6, the pigs were given 200 g of the corresponding diet labeled by ⁶⁷Zn for 2 h. We measured feed intake, fecal Zn concentration and ⁶⁷Zn abundance for the determination of apparent absorption, true absorption and endogenous fecal excretion of Zn. Although the apparent absorption of Zn did not significantly differ between the dietary groups, the phytase group had significantly more ( P  < 0.05) true absorption of Zn than the control group. The endogenous fecal excretion of Zn tended to be more ( P  = 0.07) in the phytase group than in the control group. These results suggest that dietary phytase improves Zn bioavailability through increasing the true absorption of Zn in growing pigs, which results in stimulating the endogenous fecal excretion of Zn when dietary Zn satisfies its requirement.     

Assessment of dietary zinc requirement of weaned piglets fed diets with or without microbial phytase

Fifty-four pigs, weaned at 26 days of age at an average body weight of 7.74 kg were used in a 26-day experiment to assess the zinc requirement of piglets, using diets based on maize and soybean meal, with or without microbial phytase. The nine experimental diets were the basal diet containing 33 mg of zinc/kg supplemented with 10, 25, 40, 60 or 80 mg of zinc as sulphate (ZnSO(4), 7H(2)O)/kg and the basal diet supplemented with 0, 10, 25 or 40 mg of zinc as sulphate/kg and 700 units (U) of microbial phytase (Natuphos)/kg. Pigs were fed the basal diet for a 7-day adjustment period prior to the 19-day experimental period. Microbial phytase enhanced plasma alkaline phosphatase (AP) activity, plasma zinc and bone zinc concentrations. These parameters increased linearly with zinc intake, with a similar slope with and without phytase. The response of bone zinc-to-zinc added did not plateau. Without microbial phytase, plasma AP activity and zinc concentration were maximized when dietary zinc reached 86 and 92 mg/kg respectively. With microbial phytase they were maximized when dietary zinc concentration reached 54 and 49 mg/kg respectively. Accounting for a safety margin, the recommended supply of zinc for weaned piglets up to 16 kg fed maize-soybean meal diets supplemented with zinc as sulphate is thus of 100-110 mg/kg diet. This supply may be reduced by around 35 mg if the diet is supplemented with 700 U of microbial phytase.     

植酸酶在生长猪中的研究及应用进展

在生长猪日粮中添加植酸酶可以提高猪对钙磷的利用率,提高生长猪的生长性能,降低营养物质排泄量,减少环境污染。文章综述了添加植酸酶对生长猪钙、磷、氨基酸等的表观消化率、血清生化指标的影响,与其他酶的配合使用效果以及在猪生产中的应用效果,旨在为生产提供理论依据。     

Phytate in pig and poultry nutrition

Phosphorus (P) is primarily stored in the form of phytates in plant seeds, thus being poorly available for monogastric livestock, such as pigs and poultry. As phytate is a polyanionic molecule, it has the capacity to chelate positively charged cations, especially calcium, iron and zinc. Furthermore, it probably compromises the utilization of other dietary nutrients, including protein, starch and lipids. Reduced efficiency of utilization implies both higher levels of supplementation and increased discharge of the undigested nutrients to the environment. The enzyme phytase catalyses the stepwise hydrolysis of phytate. In respect to livestock nutrition, there are four possible sources of this enzyme available for the animals: endogenous mucosal phytase, gut microfloral phytase, plant phytase and exogenous microbial phytase. As the endogenous mucosal phytase in monogastric organisms appears incapable of hydrolysing sufficient amounts of phytate‐bound P, supplementation of exogenous microbial phytase in diets is a common method to increase mineral and nutrient absorption. Plant phytase activity varies greatly among species of plants, resulting in differing gastrointestinal phytate hydrolysis in monogastric animals. Besides the supplementation of microbial phytase, processing techniques are alternative approaches to reduce phytate contents. Thus, techniques such as germination, soaking and fermentation enable activation of naturally occurring plant phytase among others. However, further research is needed to tap the potential of these technologies. The main focus herein is to review the available literature on the role of phytate in pig and poultry nutrition, its degradation throughout the gut and opportunities to enhance the utilization of P as well as other minerals and nutrients which might be complexed by phytates.     

低锌饲粮添加植酸酶对1～4周龄鹅生长性能、胫骨发育、免疫性能及抗氧化能力的影响

本试验旨在研究低锌饲粮添加植酸酶对1~4周龄鹅生长性能、胫骨发育、免疫性能及抗氧化能力的影响,探索饲粮添加植酸酶能否提高锌生物学效价和有效降低锌的添加水平。选用1日龄五龙鹅360只,随机分为6组,每组6个重复,每个重复10只鹅(公母各占1/2)。Ⅰ组为正对照组,饲喂基础饲粮,添加80 mg/kg硫酸锌,未添加植酸酶;Ⅱ组为负对照组,饲喂基础饲粮,添加1 200 U/kg植酸酶,未添加锌;Ⅲ~Ⅵ组在负对照组的基础上分别添加16、32、48、64 mg/kg硫酸锌。试验期28 d。结果表明:1)通过二次曲线拟合分析,在饲粮添加1 200 U/kg植酸酶的条件下,饲粮锌添加水平为34.00~44.70 mg/kg时可获得最佳平均日增重与料重比。2)Ⅳ、Ⅴ组的骨密度(BMD)显著高于Ⅱ组(P0.05);Ⅳ、Ⅴ组的骨矿含量(BMC)和血清碱性磷酸酶(AKP)活性显著或极显著高于Ⅰ、Ⅱ组(P0.05或P0.01)。通过二次曲线拟合分析,饲粮锌添加水平为51.38 mg/kg时,血清AKP活性最大。3)Ⅳ组的血清和肝脏总抗氧化能力(T-AOC)显著高于Ⅱ组(P0.05),与Ⅰ组差异不显著(P0.05)。通过二次曲线拟合分析,饲粮锌添加水平分别为50.24和47.49 mg/kg时,血清和肝脏的T-AOC最大。4)Ⅲ~Ⅵ组的胸腺指数和法氏囊指数均显著或极显著高于Ⅰ、Ⅱ组(P0.05或P0.01);Ⅳ~Ⅵ组免疫前后的血清新城疫抗体水平均显著或极显著高于Ⅰ、Ⅱ组(P0.05或P0.01)。由此可见,饲粮中添加植酸酶可以提高1~4周龄五龙鹅的生长性能,促进胫骨发育,增强机体抗氧化能力和免疫性能,有效提高锌利用率,降低饲粮中锌添加水平,增加锌的生物学效价。在饲粮添加1 200U/kg植酸酶的条件下,锌适宜添加水平为44.70~51.38 mg/kg。     

植酸酶对肉仔鸡不同锌源生物利用率的影响

为评定植酸酶添加对不同锌源生物利用率的影响 ,选用 5 6 0只 4日龄肉用公鸡进行为期 2 4d的饲养试验。结果表明 :不管日粮添加植酸酶与否 ,ZnAA的生物利用率均高于ZnSO4 。日粮添加植酸酶ZnAA的相对生物利用率(ZnSO4 为 10 0 )分别为 :10 3(体增重 ) ,10 3.7(饲料转化率 ) ,114 .4 (脱脂胫骨锌含量 ) ,114 .5 (胫骨灰分锌含量 )和 10 8.9(胫骨总锌含量 )。日粮不加植酸酶组这些值相应为 12 0 .8,116 .0 ,139.1,14 1.6和 116 .9。     

低锌水平秸秆饲粮中添加植酸酶对516周龄五龙鹅生长性能、胫骨发育及抗氧化能力的影响

本试验旨在研究低锌水平秸秆饲粮中添加植酸酶对5~16周龄五龙鹅生长性能、胫骨发育及抗氧化能力的影响。选用5周龄五龙鹅360只,随机分为6组,每组6个重复,每个重复10只(公母各占1/2)。Ⅰ组为对照组,饲喂基础饲粮(添加75 mg/kg硫酸锌,未添加植酸酶);ⅡⅥ组在基础饲粮的中分别添加0、15、30、45、60 mg/kg硫酸锌,且均添加1 200 U/kg植酸酶。试验期12周。结果表明:1)Ⅳ、Ⅴ组的体重和平均日增重均极显著高于Ⅰ、Ⅱ组(P0.01),Ⅳ组的平均日采食量显著或极显著高于Ⅰ、Ⅱ组(P0.05或P0.01),Ⅳ、Ⅴ组的料重比显著或极显著低于Ⅰ、Ⅱ组(P0.05或P0.01)。由曲线回归方程得出,饲粮中硫酸锌的添加水平为60.50 mg/kg时平均日增重最大;饲粮中硫酸锌的添加水平为43.44 mg/kg时料重比最低。2)ⅢⅥ组的屠宰率显著或极显著高于Ⅰ、Ⅱ组(P0.05或P0.01),Ⅱ组的半净膛率显著低于其他组(P0.05)。3)ⅣⅥ组的骨密度(BMD)显著或极显著高于Ⅱ组(P0.05或P0.01),ⅣⅥ组的骨中钙、磷含量显著或极显著高于Ⅰ、Ⅱ组(P0.05或P0.01)。4)ⅣⅥ组血清和肝脏总抗氧化能力(T-AOC)显著或极显著高于Ⅱ组(P0.05或P0.01),饲粮中硫酸锌的添加水平为45mg/kg时,血清和肝脏的总抗氧化能力最高。由此可见,低锌水平秸秆饲粮中添加植酸酶提高了516周龄鹅的生长性能,促进了胫骨发育,增强了机体抗氧化能力。饲粮中添加植酸酶能够通过提高锌的生物学效价,降低饲粮中硫酸锌的添加水平。在饲粮中添加1 200 U/kg植酸酶的条件下,饲粮中硫酸锌的适宜添加水平为4060 mg/kg。     

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.     

Efficacy of a genetically modified yeast phytase on phosphorus bioavailability in a corn-soybean meal based diet for growing pigs

We investigated the efficacy of genetically modified yeast (GMY) phytase on phosphorus (P) bioavailability in growing pigs fed a corn–soybean meal based diet. Crossbred barrows were fed a P-adequate, a low-P or a P-deficient diet containing 0.37, 0.27 and 0.14% non-phytate-P, respectively. The P-deficient diet was supplemented with wild-type yeast (WTY), Aspergillus (ASP) or GMY phytase at 750 PU per kilogram of food. Dietary ASP and GMY phytases increased plasma inorganic P (P_i) concentration and the apparent absorption of P, and decreased the concentration of a bone resorption marker, plasma type-I collagen C-terminal telopeptide (ICTP). Wild-type yeast phytase also increased the apparent absorption of P, but the changes in plasma P_i and ICTP concentrations were not significant. Although the dietary P_i-equivalencies based on plasma P_i and ICTP concentrations did not differ between WTY and ASP phytases, the equivalency of ASP phytase based on apparent absorption of P was higher than that of WTY phytase. The equivalency of GMY phytase calculated from each parameter was higher than that of WTY phytase, and did not differ from that of ASP phytase. These results suggest that efficacy of GMY phytase on P bioavailability was higher than WTY phytase, and as effective as ASP phytase in growing pigs.     

Relationship between mineral availabilities and dietary phytate in animals

A large amount of phosphorus (P) in corn and soybean meal is in the form of phytate that is poorly available to monogastric animals. It leads to the presence of large amounts of P in manure, which contributes to the P pollution problem. The fermentation of soybean meal with Aspergillus usamii almost completely degraded phytate and improved P availability in chicks. Although dietary yeast phytase increased P absorption and availability in pigs, its efficacy was less than that of Aspergillus niger phytase. It was suggested that the lesser efficacy of yeast phytase resulted from its lower stability against pepsin. Phytate suppresses zinc availability in monogastric animals. Zinc availability was improved by the substitution of regular soybean meal with fermented soybean meal and by the supplementation with Aspergillus niger phytase in pigs. It has been considered that phytate is easily degraded in the rumen and the availability of phytate P is high in ruminants. However, 20% of phytate in oilseed meals was not degraded in the rumen of sheep. Additionally, heating and formaldehyde treatments with oilseed meals suppressed ruminal degradation of phytate and approximately half of phytate escaped from ruminal degradation in the treated oilseed meals.