动物营养学报  2013, Vol. 25 Issue (9): 2082-2090   PDF (1024KB)    
液态复合酶制剂对肉鸭生长性能及钙、磷代谢的影响
黄学琴1, 任周正1, 曾秋凤1 , 张克英1 , 丁雪梅1, 白世平1, 罗玉衡1, 刘永刚2    
1. 四川农业大学动物营养研究所, 动物抗病营养教育部重点实验室, 雅安 625014;
2. 安迪苏亚太私人有限公司, 新加坡 179360
摘要:本试验旨在研究不同营养水平饲粮中添加液态复合酶制剂对肉鸭生长性能及胫骨和血清钙(Ca)、磷(P)代谢的影响。选择640只1日龄樱桃谷肉公鸭,随机分为5个处理,分别为正对照(PC)组、负对照1(NC1)组、负对照2(NC2)组(在PC组基础上降低418.00 kJ/kg ME、2.50% DAA、0.20% AP和0.15% Ca)以及在NC1和NC2组中分别添加液态复合酶制剂(0.2 mL/kg)的加酶(NC1+E、NC2+E)组,其中PC、NC1和NC1+E组为10个重复,NC2和NC2+E组为5个重复,每个重复16只鸭。试验分前期(1~21日龄)和后期(22~35日龄)2个阶段饲养。结果表明:1)与PC组相比,NC1组肉鸭各期生长性能及胫骨粗灰分(Ash)、Ca和P含量极显著降低(P<0.01),1~35日龄死亡率极显著提高(P<0.01),7和21日龄血清Ca含量及35日龄血清P含量极显著降低(P<0.01),35日龄血清碱性磷酸酶(ALP)活性极显著提高(P<0.01);2)与PC组相比,NC2组肉鸭各期生长性能及胫骨Ash、Ca和P含量进一步极显著降低(P<0.01),7和21日龄血清Ca含量和21日龄血清P含量极显著降低(P<0.01);与NC1组相比,NC2组肉鸭各期生长性能及胫骨Ash、Ca和P含量、21日龄血清P含量以及ALP活性均极显著降低(P<0.01);3)与NC1和NC2组相比,NC1+E和NC2+E组肉鸭体重(BW)、体增重(BWG)和采食量(FI)均极显著提高(P<0.01),NC1+E组胫骨Ash、Ca和P含量极显著提高(P<0.01);NC1+E和NC2+E组死亡率极显著降低(P<0.01)。以上结果提示,以植酸酶和非淀粉多糖酶为主的液态复合酶制剂可明显缓解饲粮低营养水平,尤其是AP水平降低对肉鸭生长性能及Ca、P代谢造成的不利影响。
关键词复合酶     肉鸭     生长性能     钙、磷代谢    
Effects of Liquid Compound Enzyme Preparation on Growth Performance and Calcium and Phosphorus Metabolism of Meat Ducks
HUANG Xueqin1, REN Zhouzheng1, ZENG Qiufen1 , ZHANG Keying1 , DING Xuemei1, BAI Shiping1, LOU Yuheng1, LIU Yonggang2    
1. Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Institute of Animal Nutrition, Sichuan Agricultural University, Ya'an 625014, China;
2. Adisseo Asia Pacific Pte Ltd., Singapore 179360, Singapore
Abstract: This study was conducted to investigate the effects of liquid compound enzyme preparation on the growth performance, serum and bone calcium and phosphorus metabolism of meat ducks supplementation in different nutrient level diets. A total of 640 one-day-old male Cherry Valley ducks were randomly allocated into 5 treatments, the treatments included: positive control (PC) group, negative control 1 (NC1) group, negative control 2 (NC2) group (decreased 418 kJ/kg ME, 2.50% DAA, 0.20% AP and 0.15% Ca on the basis of PC group), and NC1+E and NC2+E groups which supplemented with 0.2 mL/kg liquid compound enzyme preparation on the basis of NC1 and NC2 group. PC, NC1 and NC1+E groups contained 10 replicates, NC2 and NC2+E groups contained 5 replicates, and each replicate contained 16 ducks. The study included two periods: starter (1 to 21 days of age) and later (22 to 35 days of age). The results showed as follows: 1) compared with PC group, the growth performance and the contents of ash, P and Ca in tibia in NC1 group were significantly decreased in all periods (P<0.01), the mortality at 1 to 35 days of age was significantly increased (P<0.01), the serum Ca content at 7 and 21 days of age and serum P content at 35 days of age were significantly decreased (P<0.01), and the serum ALP activity at 35 days of age was significantly increased (P<0.01). 2) Compared with PC group, the growth performance and the contents of ash, P and Ca in tibia in NC1 group were significantly decreased in all periods (P<0.01), the serum Ca content at 7 and 21 days of age and serum P content at 21 days of age were significantly decreased (P<0.01); compared with NC1 group, the growth performance, the contents of ash, phosphorous (P) and Ca in tibia, serum P content and alkaline phosphatase (ALP) activity at 21 days were significantly decreased (P<0.01). 3) Compared with NC1 and NC2 groups, the body weight, body weight gain and feed intake in NC1+E and NC2+E groups was significantly increased (P<0.01), the contents of ash, P and Ca in tibia in NC1+E group were significantly increased (P<0.01); and the mortality in NC1+E and NC2+E groups was significantly decreased (P<0.01). These results indicate that the liquid compound enzyme preparation containing non-starch polysaccharides enzyme and phytase can alleviate the negative effects caused by the low nutrient level, especially the negative effects on growth performance, calcium and phosphorus metabolism caused by the reduction of AP level.
Key words: compound enzyme     meat ducks     growth performance     calcium and phosphorus metabolism    

随着养殖业与饲料工业的快速发展,玉米、豆粕等常规优质原料价格持续上涨,为降低动物饲养成本,非常规原料 逐渐广泛且大量用于家禽饲料中。但由于这些饲料原料中含有较高的植酸和非淀粉多糖(NSP)等抗营养因子,影响了动物对饲料的高效利用。随着酶制剂生产和应用技术的不断发展,大量研究和生产实践证明在畜禽饲粮中通过添加酶制剂可消除植酸和NSP的抗营养作用。且植酸酶与NSP酶具有协同效应[1, 2]或加性效应[3, 4, 5],合用效果优于单一使用。Francesch等[6]报道,在适宜营养水平 的基础上分别降低355 kJ/kg ME、3%可消化氨基酸(DAA)、0.2% AP和0.16% Ca后添加NSP酶与植酸酶的液态复合酶制剂,可显著提高肉鸡的生长性能和胫骨质量,其中生长性能达到正常营养水平,Francesch等[6]认为该酶制剂可为肉鸡饲料配方节约355 kJ/kg ME、3% DAA、0.2% AP和0.16% Ca。肉鸡和肉鸭因肠道消化特性的差异导致对饲料营养物质利用存在显著的差异[7, 8],且肉鸭耐粗饲能力强,商品饲料几乎都是玉米杂粕型,其中抗营养因子含量更高,因此,复合酶制剂是否在肉鸭饲料中也有很好的应用效果,目前研究报道较为缺乏。为此,本试验以樱桃谷肉鸭为研究对象,在降低不同水平的ME、DAA、Ca和AP饲粮中添加植酸酶和NSP酶的液态复合酶制剂,考察其对肉鸭生长性能及胫骨和血清Ca、磷(P)代谢的影响,寻求该复合酶制剂替代基础饲粮的适宜ME、DAA、Ca和AP水平,为该酶制剂在肉鸭生产中的合理应用提供试验依据。

1 材料与方法
1.1 试验材料

液态复合酶制剂由安迪苏亚太私人有限公司提供,其添加量为0.2 mL/kg,可为每千克饲粮提供木聚糖酶1 100 U、β-葡聚糖酶100 U和植酸酶500 U。

1.2 试验设计与试验动物

试验采用2×2+1因子设计,选择640只1日龄健康樱桃谷肉公鸭,随机分为5个组,分别为正对照(PC)组、负对照1(NC1)组(在PC组基础上降低334.40 kJ/kg ME、2.00% DAA、0.15% AP和0.10% Ca)、负对照2(NC2)组(在PC组基础上降低418.00 kJ/kg ME、2.50% DAA、0.20% AP和0.15% Ca)以及在NC1和NC2组中分别添加液态复合酶制剂(0.2 mL/kg)的加酶(NC1+E、NC2+E)组。鉴于低AP水平可能导致肉鸭死亡,试验中最低AP水平组(NC2和NC2+E组)各设5个重复,其余组各10个重复,每个重复16只鸭。

1.3 试验饲粮

试验饲粮为玉米-豆粕-杂粕-米糠型,饲料原料营养成分参照《中国饲料成分及营养价值表2008》。试验分前期(1~21日龄)和后期(22~35日龄)。全程采用颗粒料,制粒温度80 ℃,前期料颗粒直径2.0 mm,后期料颗粒直径3.5 mm;试验饲粮组成及营养水平见表1。 饲粮前期和后期必需氨基酸平衡模式分别为可消化赖氨酸(DLys)∶ 可消化蛋氨酸(DMet)∶ 可消化苏氨酸(DThr)∶ 可 消化色氨酸(DTrp)=100∶ 48∶ 66∶ 27和100∶ 44∶ 67∶ 23[9]。液态复合酶制剂在制粒后用小型喷雾器喷涂。

1.4 指标测定
1.4.1 生长性能

试验第21和35天20:00以重复为单位结算鸭只采食量(FI),断料至次日08:00,以重复为单位空腹称重,计算各阶段鸭体重(BW)、体增重(BWG)、FI和料重比(F/G)。记录各阶段试验鸭死亡情况,计算各阶段死亡率。

1.4.2 血清Ca、P含量和碱性磷酸酶(ALP)活性

试验第8、22和36天各重复选择1只空腹、最接近平均BW的试验鸭颈静脉采血12 mL,3 000 r/min、4 ℃离心10 min取上层血清存于EP管-20 ℃保存,采用全自动生化分析仪测定血清Ca、P含量及ALP活性。

1.4.3 胫骨粗灰分(Ash)、Ca和P含量

试验第8、22和36天各重复选择1只空腹、接近平均BW的鸭只,颈部脱臼处死,分离左侧胫骨于样品袋,-20 ℃保存。测定前,胫骨用沸水煮沸5 min后,完全分离胫骨上的肌肉和结缔组织,经乙醚脱脂24 h后,置于105 ℃烘箱24 h,550 ℃灰化,灰化后进行Ash、Ca、P含量的测定[10]

1.5 统计分析

试验数据采用SPSS 17.0软件进行单因素方差分析,差异显著者用Duncan氏法进行多重比较。数据以平均值±标准误表示,以P<0.05为差异显著,P<0.01为差异极显著。

表1 试验饲粮组成及营养水平(风干基础)

Table 1 Composition and nutrient levels of experimental diets (air-dry basis) %


2 结 果
2.1 液态复合酶制剂对肉鸭生长性能的影响

由表2可知,21日龄NC1和NC2组肉鸭BW极显著降低(P<0.01),与NC1组相比,NC1+E组肉鸭BW极显著提高(P<0.01);与NC2组相比,NC2+E组肉鸭BW显著提高(P<0.05)。1~21日龄,与PC组相比,NC1和NC2组肉鸭BWG和FI均极显著降低(P<0.01);NC1和NC2组F/G及NC2组死亡率极显著提高(P<0.01);与NC1组相比,NC1+E组肉鸭BWG和FI极显著提高(P<0.01),但未达到PC组水平,两者差异极显著(P<0.01),对F/G改善不显著(P>0.05);与NC2组相比,NC2+E组BWG显著提高(P<0.05),FI极显著提高(P<0.01),死亡率极显著降低(P<0.01)。

35日龄NC2+E组肉鸭BW极显著低于其他各组(P<0.01),与PC组相比,NC1组BW极显著降低(P<0.01),与NC1组相比,NC1+E组肉鸭BW极显著提高(P<0.01)。22~35日龄,NC2组鸭只全部死亡;NC2+E组肉鸭BWG和FI均极显著低于其他各组(P<0.01);与PC组相比,NC1组BWG和FI极显著降低(P<0.01),死亡率极显著提高(P<0.01);与NC1组相比,NC1+E组肉鸭BWG极显著提高(P<0.01),FI显著提高(P<0.05),对F/G改善不显著(P>0.05),极显著降低死亡率(P<0.01),其中BWG和FI未达到PC组水平(P<0.01),死亡率达到PC组水平,两者差异不显著(P>0.05)。1~35日龄与22~35日龄结果类似。

表2 液态复合酶制剂对肉鸭生长性能的影响

Table 2 Effects of liquid compound enzyme preparation on growth performance of meat ducks



2.2 液态复合酶制剂对肉鸭血清Ca、P含量和ALP活性的影响

由表3可知,与PC组相比,NC1和NC2组7和21日龄血清Ca含量均极显著降低(P<0.01);NC1组对7日龄血清P含量无显著影响(P>0.05),21日龄血清P含量极显著提高(P<0.01);35日龄血清P含量显著降低(P<0.05),35日龄ALP活性极显著提高(P<0.01);NC2组21日龄血清P含量极显著降低(P<0.01)。与NC1组相比,NC1+E组35日龄血清P含量显著提高(P<0.05),35日龄血清ALP活性极显著降低(P<0.01)。与NC2组相比,NC2+E组7日龄血清Ca含量显著提高(P<0.05),21日龄血清P含量及ALP活性极显著提高(P<0.01)。

表3 液态复合酶制剂对肉鸭血清钙、磷含量和碱性磷酸酶活性的影响

Table 3 Effects of liquid compound enzyme preparation on calcium and phosphorus contents, and

alkaline phosphatase activity in serum of meat ducks mmol/L



2.3 液态复合酶制剂对肉鸭胫骨Ash、Ca和P含量的影响

由表4可知,与PC组相比,NC1和NC2组胫骨Ash、Ca和P含量均极显著降低(P<0.01)。与NC1组相比,NC1+E组胫骨Ash、Ca和P含量极显著提高(P<0.01),但均极显著低于PC组(P<0.01)。与NC2组相比,NC2+E组显著提高了21日龄胫骨Ca含量(P<0.05),但对胫骨P和Ash含量影响不显著(P>0.05)。

3 讨 论
3.1 营养水平及添加液态复合酶制剂对肉鸭生长性能的影响

在一定范围内降低饲粮能量可增加动物的FI。Xie等[11]在0~3周龄北京鸭上的研究发现,饲粮ME水平从12.75 MJ/kg降低至10.26 MJ/kg,FI和F/G显著提高,其中ME水平从12.14 MJ/kg降低到11.50 MJ/kg时FI提高不显著。在本研究中,NC1和NC2组分别在PC组(12.12 MJ/kg)的基础上降低了334.40和418.00 kJ/kg的ME,未能提高动物的FI,可能是因为本试验中PC组饲粮AP水平设置为0.40%,在此基础上降低0.15%和0.20%的饲粮AP后使饲粮AP水平成为导致NC1和NC2组肉鸭FI与生长性能下降的主要因素。众多的研究者发现,AP缺乏导致动物BW、FI降低,F/G提高[12, 13, 14]。P缺乏直接导致的肉鸭骨骼发育障碍和腿病,限制鸭只的采食、饮水等行为的正常进行,严重影响生长性能,导致死亡。本试验也发生类似的现象,当肉鸭饲粮AP水平1~21日龄为0.25%,22~35日龄为0.20%时,肉鸭表现出腿无力,无法采食与饮水,直接导致死亡。由于植酸酶能够水解植酸释放无机P[15],Adeola[16]以7日龄肉鸭为研究对象,发现500、1 000和1 500 U/kg植酸酶的P当量分别为0.453、0.847和1.242 g/kg饲粮。在家禽饲粮中添加植酸酶能显著提高动物BW、BWG和FI[17, 18],弥补饲粮P的不足。本试验得到类似的结果,添加液态复合酶制剂(植酸酶500 U/kg)到NC1和NC2组中,显著提高了肉鸭BW、BWG和FI,但是NC1+E组的BW、BWG和FI仍然低于PC组,可能的原因一方面是该液态复合酶制剂释放出AP值低于原本预计的0.15%,另一方面是基础饲粮本身植酸磷含量较低,导致酶制剂的作用不能完全发挥出来。有研究发现,当P为饲粮第一限制营养因子时,添加木聚糖酶对肉鸡的生长性能没有显著影响[19],这与本试验液态复合酶制剂的添加并没有显著改善肉鸭F/G是一致的。Adeola等[20]在肉鸭上研究发现,在高黏度小麦饲粮中添加木聚糖酶可提高能量、脂肪、氮和淀粉的消化率,但在低黏度小麦饲粮中没有得到类似的结果。从以上研究结果及其他研究结果[21, 22, 23]反映出NSP酶在肉鸭饲粮中的使用效果受基础饲粮组成、饲粮营养水平以及酶制剂质量等诸多因素的影响。

表4 液态复合酶制剂对肉鸭胫骨粗灰分、钙和磷含量的影响

Table 4 Effects of liquid compound enzyme preparation on contents of tibia ash,

calcium and phosphorus of meat ducks %



3.2 营养水平及添加液态复合酶制剂对肉鸭Ca、P代谢的影响

本试验发现,饲粮AP和Ca水平降低对血清Ca、P含量和ALP活性影响的规律性不强,饲粮AP水平的降低并未显著降低1~21日龄血清P含量,其可能原因是动物缺P后机体通过自身的调节机制调节骨骼中的Ca、P代谢来维持血清P含量[24]。而35日龄血清P含量显著降低,与其他研究者的结果一致[14, 25],其可能是由于肉鸭长期缺P后自身的调节能力已不能缓解。Viveros等[14]研究发现,在肉鸡AP水平低的饲粮中添加植酸酶可显著提高血浆P含量,另外较多研究结果也表明,植酸酶可显著提高血清P含量[26, 27, 28]。本试验结果表明,添加含500 U/kg植酸酶的液态复合酶制剂后35日龄肉鸭血清P含量提高了51.4%。由于ALP有50%来自骨组织,在Ca、P代谢紊乱时,是骨形成和转换的重要指标。本试验结果显示,随着饲粮Ca和AP水平的降低,ALP活性显著提高,添加酶制剂后,ALP活性降低,这与许多研究结果相一致[14, 29, 30],因为在低P饲粮添加酶制剂可使P的利用率增加,骨P周转变慢,从而使血清ALP活性降低。但在本试验中,加酶后肉鸭血清ALP活性未降低到与PC组一致的水平,说明加酶后所释放的P仍不能满足肉鸭的需要,肉鸭仍处于P缺乏状态。

相对于生长性能和血清Ca、P代谢指标,胫骨Ash、Ca和P是体现动物对饲粮Ca、P缺乏较敏感的指标。有研究发现,动物满足胫骨生长所需要的Ca、P要高于满足生产需要[6]。饲粮中Ca、P缺乏或者P缺乏均会导致动物胫骨Ash、Ca和P含量的降低。在本研究中,饲粮AP水平降低显著降低了肉鸭胫骨Ash、Ca和P的含量。在低P饲粮中添加植酸酶可显著提高胫骨Ash、Ca和P含量[6, 31],本研究也有类似的结果,但在本研究添加含有500 U/kg植酸酶的液态复合酶制剂后,胫骨Ash、Ca和P含量虽显著提高,但均未达到PC组水平,这说明动物所缺的P超过了该液态复合酶制剂的缓解范围。

4 结 论

① 在本试验条件下,在PC组基础上,降低饲粮ME、DAA、Ca和AP水平,极显著降低了肉鸭的生长性能及胫骨Ash、Ca和P含量,不同程度降低了血清Ca、P含量,显著提高了肉鸭死亡率,其中,当AP水平降低至0.20%(1~21日龄)和0.15%(22~35日龄)时,21日龄后肉鸭全部死亡。

② 在低营养水平饲粮中添加0.2 mL/kg液态复合酶制剂可极显著提高肉鸭BW、BWG和FI,显著提高35日龄血清P含量,其中NC1+E组极显著提高了胫骨Ash、Ca和P含量。

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