植酸磷和植酸酶研究进展

大量研究结果显示,植酸酶在动物生产和环境保护方面具有很好的应用前景。本文从植酸磷和有效磷的关系、植酸磷测定方法、饲料中的植酸磷含量、植酸酶的来源和植酸酶在畜禽饲料中的应用等方面,就近10年来对植酸磷和植酸酶的研究动态和进展进行了简要综述。     

植酸酶和纤维素酶对蛋鸡生产性能的影响及蛋鸡非植酸磷需要量研究

选用18周龄海赛克192只 ,研究了玉米—豆粕型日粮中添加植酸酶和纤维素酶对蛋鸡生产性能的影响以及蛋鸡对非植酸磷的需要量。采用2×2×2因子正交试验设计(L827) ,基础日粮为玉米—豆粕型 ,含玉米60 % ,豆粕27 % ,两个水平非植酸磷(0.38 %、0.16 %) ,两个水平植酸酶(300IU/kg,0) ,两个水平纤维素酶(0.1 % ,0)。试鸡随机分为8组 ,每组4个重复 ,每个重复6只鸡。试验饲养期共7个月。试验结果表明 ,玉米—豆粕型日粮添加0.1 %纤维素酶有降低试鸡日采食量的趋势。添加300IU/kg 植酸酶和0.1 %纤维素酶及其他各因素处理对蛋鸡全试验期平均产蛋率…     

钙和非植酸磷浓度对肉仔鸡利用植酸酶效果的影响

通过比较在添加植酸酶(试验1)和不添加植酸酶(试验2)时的生产性能和骨骼质量参数的表观回归曲线,研究不同水平C a和非植酸磷(NPP)的日粮中添加植酸酶的效果。在这2个试验中,0~16日龄的Cobb×Cobb肉仔鸡饲喂玉米-豆粕型基础日粮。试验1采用4×4因子设计,钙水平分别为:0.38%、0.58%、0.78%和0.98%,NPP水平分别为:0.2%、0.3%、0.4%和0.5%。试验2采用混合循环试验设计,日粮中C a水平为0.38%、0.47%、0.68%、0.89%和0.98%,NPP水平为0.20%、0.24%、0.35%、0.46%和0.50%。需要指出的是,设计中同时含有一个最低水平的C a和NPP(0.38%C a和0.20%NPP)组合。所有C a和NPP的组合均添加657U/kg的N atuphos 5000植酸酶,此外,其中的4个组合(0.38%C a和0.20%NPP,0.47%C a和0.24%NPP,0.68%C a和0.35%NPP及0.89%C a和0.46%NPP)不添加植酸酶,用以确定试验中多个表观回归曲线间比较特殊变量的可行性。通过比较添加与不添加植酸酶的表观曲线,结果显示:在高C a低NPP条件下,植酸酶对生长性能和骨质量的影响最明显,但当C a水平降低或NPP水平提高的情况下,植酸酶的影响程度有所下降。第3个试验证明了在高C a低NPP比低C a低NPP时,植酸酶更能发挥其功效。以上数据说明,在添加植酸酶时,不能仅以单独的NPP等价量来确定其添加量。     

育肥蛋公雏非植酸磷适宜需要量的研究

采用单因子完全随机试验设计,选用“尼克T”白蛋公雏240只,随机等分为6个处理组,每个处理组设4个重复,每个重复10只鸡,并随机分配给6种试验日粮。以玉米-豆粕型日粮为基础日粮(表观代谢能、粗蛋白质、总钙、非植酸磷,0～5周龄和6～10周龄依次分别为13.47MJ/kg、20%、1%、0.22%;13.56MJ/kg、19.3%、1%、0.22%),向基础日粮中等梯度添加参试物磷酸氢钙,使非植酸磷(NPP)添加水平依次分别为0%、0.1%、0.2%、0.3%、0.4%、0.5%。测定育肥蛋公雏,0～5、6～10周龄采食量、体增重、骨骼灰分、骨骼磷含量,预测最佳生产性能时磷的需要量。结果表明:在本试验条件下,以体增重、胫骨灰分含量、趾骨灰分含量、胫骨磷含量、趾骨磷含量为指标测得的育肥蛋公雏NPP需要量0～5周龄、6～10周龄依次分别为:0.48%、0.51%、0.52%、0.51%、0.5%;0.41%、0.5%、0.49%、0.5%、0.5%。     

植酸磷水平对植酸酶使用效果的影响

选用135头体质健康、体重60kg左右的杜×大×长三元杂交猪,随机分为5个处理组,研究不同植酸磷水平对植酸酶使用效果的影响。试验结果表明,加植酸酶情况下,有效磷达0.165%、植酸磷水平为0.25%时大猪的生长性能最好。玉米—豆粕型大猪饲粮中的植酸磷水平能使500IU/kg的植酸酶发挥正常功效,一般不会出现“底物”不足的情况。     

维生素D3的来源和添加量对鸡饲料中植酸磷与非植酸磷利用的影响

2周龄和3周龄的商品、实验杂交品系鸡对1α-O-HD_3有显著的反应(P<0.01)。当在过量胆钙化醇(D_3,25μg/kg)但含磷不足的玉米-豆粕饲粮中添加20μg/kg1a—OHD_3后,鸡骨灰分反应超过50％,磷的排泄量降低(P<0.01),同时,磷的沉积量增加(P<0.01)。本试验用不含D_3、磷不充足的酪氨酸纯净饲粮饲喂鸡,确定添加15μg/kg的D_3。是否足以使非植酸磷的吸收达理想状态。添加0.075％的磷(KH_2PO_4)对骨灰分有影响,同时,饲喂含非植酸磷0.175％饲粮的鸡,其骨灰分对添加的15μg/kg D_3或10μg/kglα—OHD_3进一步表现出明显的反应。但对更高水平的这此D_3成分却再没有出现其他反应。这表明在磷不足(0.28％的植酸磷和0.14％的非植酸磷)的玉米-豆粕饲粮中,15-25μg/kg的D_3足以使非值酸磷达理想吸收状态。饲喂含磷不足(0.13％非植酸磷和15μg/kgD_3)的酪蛋白-右旋糖饲粮,鸡的骨灰分对1α—OHD_3或微生物植酸酶(1470单位/kg)没有反应。因此,在含磷不足但至少含15μg/kgD_3。的玉米-豆粕饲粮中添加1α—OHD_3能显著提高鸡的增重和骨灰分,原因是它提高了植酸磷的利用。     

饲粮非植酸磷水平对褐壳蛋鸡植酸磷利用率的影响

150只蛋鸡随机分为5个处理组，5个处理组非植酸磷水平分别为0.2%,0.25%,0.3%,0.35%,0.4%，钙水平都为3.5%。结果表明：饲粮非植酸磷水平为0.2%时，蛋鸡对植酸磷的表观利用率为65．5％（P＜0．05）。饲粮非植酸磷水平对蛋鸡生产性能无明显影响（P＞0．05）。     

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。     

植酸酶对产蛋鸡生产性能和代谢的影响

磷酸氢钙是饲料中最主要的磷来源之一 ,无机磷资源不仅在我国 ,就是在全世界范围内 ,已经处于匮乏状态 ,磷资源的匮乏使饲用磷产品价格上升 ,增加了饲料成本。植物性饲料中有 65 %～86 %的磷以植酸磷的形式存在 ,这些磷源不仅不能为单胃动物有效利用 ,而且会对环境造成严重的污染。如果能将植酸磷中的磷释放出来供动物利用 ,减少磷酸氢钙的用量 ,可缓解供求矛盾 ,并减轻粪磷污染。本试验旨在应用植酸酶迈特 -5 0 0 0以减少产蛋鸡日粮中的磷酸氢钙用量 ,观察其对产蛋鸡生产性能和代谢的影响。1　材料与方法试验在南京市青龙山养鸡场进行 ,选…     

不同添加量植酸酶对蛋鸡生产性能的影响

选择42周龄海兰褐蛋鸡1200只,随机分成5组,设正对照组、负对照组和3个试验组。3个试验组分别饲喂负对照组日粮基础上含不同添加量植酸酶(150、300、600U/kg)的日粮(营养标准相对正对照组低0.12%有效磷)。试验期60d,考察不同添加量的植酸酶对蛋鸡生产性能的影响。试验结果表明:150U/kg添加组与正对照组生产性能相比,产蛋率提高0.22%,蛋重、采食量、料蛋比分别降低0.16%、0.42%和0.47%,统计上均无显著差异(P>0.05);150U/kg添加组与300、600U/kg添加组相比统计上也无显著差异(P>0.05)。这表明饲料中使用150U/kg该植酸酶可达到与目前市场上普遍使用300U/kg植酸酶的效果,也能满足蛋鸡营养(磷)需要。     

Effect of yeast cell wall supplementation in laying hen feed on economic viability,egg production,and egg quality

Yeast cell walls can strengthen the immune system and promote agglutination of gastrointestinal tract pathogens, thereby improving animal health and productivity. This study evaluated the effect of supplementing the diet of commercial laying hens with 0, 225, 450, or 900 ppm of yeast cell wall supplement on hen productive performance, egg quality, and economic viability. Yeast cell wall supplementation increased the feed intake, egg production, egg mass, albumen height, and Haugh unit score. Shell thickness and yolk color also were affected by the treatments. The economic viability analysis demonstrated that although feeding costs more with supplementation, the production of more eggs is possible, resulting in a greater than proportional increase in the gross margin. Thus, yeast cell wall supplementation had beneficial effects on the productive performance of laying hens, improved the internal and external egg quality, and contributed to greater profitability.     

The effect of dietary supplementation with phytase transgenic maize and different concentrations of non-phytate phosphorus on the performance of laying hens

1. The objective of this study was to evaluate the effects of dietary supplementation with phytase transgenic corn (maize) (PTC) which has a phytase activity of 21 000 units (U) phytase per kg of maize on productive performance, egg quality, tibia bone quality and phosphorus (P) excretion in laying hens.

2. In the experiment, 1800 44-week-old Hy-line brown laying hens were divided into 5 groups with 6 replicates per group and 60 hens per replicate. The experiment lasted for 12 weeks. The layers in the control group (control) were given a basal diet with 0.36% non-phytate P (NPP), while the treatment groups received diets containing 360 U of exogenous phytase/kg with 0.26% NPP (EP) or 360 phytase U of PTC/kg diet with 0.26% (PTC1), 0.21% (PTC2) or 0.16% (PTC3) NPP.

3. The results showed that there was no significant difference in egg production, average daily feed intake, feed efficiency, rate of broken or soft-shell egg production or egg mass among the treatments. There was no significant difference in eggshell thickness or eggshell strength. On the other hand, no differences in any of the bone variables were found between treatments. The faecal P percentage content in EP, PTC1, PTC2 and PTC3 groups was significantly lower than the control group.

4. In summary, the PTC could be used in the feed of laying hens instead of EP to reduce P excretion without effecting production and bone mineralisation.     

Response of broiler chickens to different levels of calcium,non-phytate phosphorus and phytase

1. Five hundred and seventy six-d old Ross 308 broiler chicks (6 cages per diet, 8 birds per cage in 3 × 2 × 2 factorial arrangement) were fed on maize–soybean meal-based diets containing three concentrations of Ca (6, 8 or 10 g/kg), two concentrations of non-phytate phosphorus (NPP) (3 or 4 g/kg) and two levels of exogenous microbial phytase (0 or 500 FTU/kg) from d 0 to 35.

2. Body weight (BW), feed intake (FI) and mortality records were collected. Two birds per replicate were killed at 24 d of age to obtain tibia samples.

3. Increasing Ca level significantly reduced the FI and body weight gain (BWG) between hatch and 10 and 24 d, especially with the phytase-supplemented diets. However, phytase supplementation of the diet containing 4 g NPP/kg improved the FI and BWG at d 10 and 24. At d 24, phytase supplementation improved feed conversion ratio (FCR) of birds that consumed diets containing high NPP. The overall FCR was better in birds offered the phytase-supplemented, medium-Ca diet.

4. There was a significant reduction in length, width and breaking strength of the tibia bone in birds fed on a diet with high Ca and low NPP. Phytase supplementation improved the tibia ash content and bone breaking strength of chicks fed on the diet containing 8 and 4 g/kg Ca and NPP, respectively. The Ca content of the tibia bone was low in birds fed on diets with 6 and 4 g/kg Ca and NPP, respectively, but this was counteracted by phytase supplementation.

5. Birds fed on diets with 4 g/kg NPP had the best carcass percentage and parts yield. Phytase supplementation to high-Ca diets significantly reduced the carcass yield of birds.

6. These results confirmed the detrimental effect of high dietary Ca on phytase activity and subsequent growth and bone development of birds, especially when NPP is in short supply.     

Effect of age of the laying hen on the composition of the egg

1. All eggs laid by a group of 16 light‐body‐weight hens during the laying year were weighed and divided into yolk, albumen and shell and the wet and dry weights of the components determined.

2. After an initial period of about 2 months, the weights of egg, water, wet albumen, wet and dry yolk increased with age, whereas those of dry albumen and wet and dry shell remained constant. Dry shell per square centimetre surface area decreased with age but water per square centimetre surface area remained constant.     

Effect of microbial phytase on production performance of White Leghorn layers fed on a diet low in non-phytate phosphorus

1. An experiment with 150 White Leghorn layers was conducted to examine the effect of microbial phytase supplementation of low non-phytate phosphorus (NPP) diets on egg production, eggshell quality, bone mineralisation and retention of nutrients at 32-48 weeks of age. 2. Four isonitrogenous and isocaloric diets were formulated to contain 1.2, 1.8, 2.4 and 3.0 g NPP/kg diet with the two lowest NPP (1.2 and 1.8) supplemented with microbial phytase (Biofeed Phytase, India) at 500 FTU per kg diet. Each diet was offered ad libitum to 5 replicates of 5 layers throughout the experiment. 3. Body weight gain was reduced significantly in the layers fed on the 1.2 g/kg NPP diet as compared to those given diets containing 1.8-3.0 g/kg. Addition of phytase to the 1.2 g/kg diet significantly enhanced the body weight and was comparable with those given diets containing 1.8-3.0 g/kg NPP. 4. No additional advantage resulted from enhancing the NPP levels beyond 1.8 g/kg or adding phytase to a diet containing 1.8 g/kg NPP. 5. Hen d egg production, food intake, food efficiency, shell weight, shell thickness, shell strength and tibia strength followed the same trends as above. However, adding phytase to the 1.8 g/kg NPP diet significantly enhanced tibia ash. Egg weight, specific gravity and Haugh units were influenced by neither NPP concentration nor phytase supplementation. 6. Adding phytase to the 1.2 g/kg NPP diet significantly enhanced nitrogen and phosphorus retention. 7. It was concluded that addition of 500 FTU of microbial phytase/kg diet can allow the reduction of NPP content to 1.2g/kg in the layer diet, eliminate inorganic phosphorus supplementation and results in significant reduction of nitrogen and phosphorus excretion without affecting the production performance of layers.     

光照与蛋鸡饲养的关系

1 光照的意义 光照是一门科学,要想养好鸡,就必须要懂得这门学问.在蛋鸡饲养上,光照与雏鸡发育、青年鸡生长、成年鸡产蛋等都有着极密切的关系.实践证明,光照的时数与强弱、光照的颜色与波长、光照刺激的起止时间、黑暗期是否连续或间断,都会对蛋鸡的成活率、生长发育、体成熟、性成熟、产蛋率以及繁衍后代的公母交配活动等方面,产生重要的影响.光照是蛋鸡饲养的重要的环境条件之一.换句话说,没有光照条件的环境,是不能进行蛋鸡饲养活动的.