离体法优化肉鸭日粮非淀粉多粮酶酶谱的研究

试验运用均匀设计,采用胃蛋白酶-胰液素两步水解法,探讨NSP酶的组成及活性对提高不同NSP含量和组成的肉鸭日粮可消化能的作用效果,为针对不同类型肉鸭基础日粮筛选优化NsP酶添加剂提供快捷有效的方法.按照均匀设计表U*15(157),将4种NSP酶组合成15个水平的复合酶配方,以5种不同NSP含量的基础日粮作为对照,并分别在这5种基础日粮中加入上述15种复合酶组成15组试验日粮.以离体法测定15组试验日粮及基础对照日粮的离体消化能,建立各个日粮中4种NSP酶添加量与离体消化能值间的四元二次回归方程,经优化求其最优解,即得到最佳酶谱配方.试验结果表明,日粮的NSP组成和含量不同,其最佳酶谱也存在较大差异,且NSP酶和日粮离体消化能之间存在显著的回归关系,因此,针对不同NSP组成和含量的日粮,可以用离体法筛选与之相对应NSP酶谱.     

离体法优化肉鸭日粮非淀粉多糖酶酶谱的研究

试验运用均匀设计,采用胃蛋白酶-胰液素两步水解法,探讨NSP酶的组成及活性对提高不同NSP含量和组成的肉鸭日粮可消化能的作用效果,为针对不同类型肉鸭基础日粮筛选优化NSP酶添加剂提供快捷有效的方法。按照均匀设计表U*15(157),将4种NSP酶组合成15个水平的复合酶配方,以5种不同NSP含量的基础日粮作为对照,并分别在这5种基础日粮中加入上述15种复合酶组成15组试验日粮。以离体法测定15组试验日粮及基础对照日粮的离体消化能,建立各个日粮中4种NSP酶添加量与离体消化能值间的四元二次回归方程,经优化求其最优解,即得到最佳酶谱配方。试验结果表明,日粮的NSP组成和含量不同,其最佳酶谱也存在较大差异,且NSP酶和日粮离体消化能之间存在显著的回归关系,因此,针对不同NSP组成和含量的日粮,可以用离体法筛选与之相对应NSP酶谱。     

预消化处理肉鸡加酶日粮中非淀粉多糖酶解效果的研究

文章旨在研究4种单体NSP酶制剂(木聚糖酶、β-葡聚糖酶、纤维素酶和甘露聚糖酶),经过预消化处理工艺后,对肉鸡日粮中的非淀粉多糖的酶解情况,为进一步研究NSP酶制剂在肉鸡日粮中的合理利用提供参考依据。结果显示,不同的NSP酶添加量对肉鸡日粮的预消化处理效果有着显著的相关关系,木聚糖酶、β-葡聚糖酶、纤维素酶、甘露聚糖酶的最佳添加水平分别为250、350、300、200 mg/kg;初步确定的预消化处理参数是:温度45℃、时间60 min、水分35%。本试验条件下,结合相关的数据分析,试验日粮中最佳酶制剂组合是:木聚糖酶186 mg/kg、β-葡聚糖酶440 mg/kg、纤维素酶337 mg/kg、甘露聚糖酶200 mg/kg(P<0.01)。研究表明,加酶日粮经过预消化处理后,可以有效地降解其中日粮的非淀粉多糖,提高日粮的营养利用率。     

酶在菜籽粕日粮中的应用研究进展

本文分析了在菜籽粕日粮中使用非淀粉多糖(NSP)酶、α-半乳糖苷酶、植酸酶、蛋白酶和淀粉酶等的必要性，并对这些酶在菜籽粕日粮中的作用机理及作用效果进行了概述，旨在为消除菜籽粕中的抗营养因子，提高菜籽粕在畜禽日粮中的应用比例及其营养价值提供一种可行的方法。     

NSP酶在家禽小麦饲粮中的应用研究进展

小麦营养价值很高,但由于其富含具有抗营养作用的阿拉伯木聚糖等非淀粉多糖(NSP),从而降低了小麦中营养物质在家禽中的利用率.NSP主要通过增加动物消化道食糜黏度,阻碍消化酶与营养物质的接触,降低饲料利用率,导致动物生产性能下降.在麦类饲粮中添加NSP酶,可有效消除其抗营养作用.论文主要介绍了非淀粉多糖的抗营养作用、非淀粉多糖酶的作用机理及其在家禽生产中的作用.     

NSP酶在家禽小麦饲粮中的应用研究进展

小麦营养价值很高,但由于其富含具有抗营养作用的阿拉伯木聚糖等非淀粉多糖（NSP）,从而降低了小麦中营养物质在家禽中的利用率。NSP主要通过增加动物消化道食糜黏度,阻碍消化酶与营养物质的接触,降低饲料利用率,导致动物生产性能下降。在麦类饲粮中添加NSP酶,可有效消除其抗营养作用。论文主要介绍了非淀粉多糖的抗营养作用、非淀粉多糖酶的作用机理及其在家禽生产中的作用。     

非淀粉多糖酶制剂在家禽日粮中的应用

在家禽饲养上,人们通常把玉米作为主要的能量饲料,随着我国规模养禽业的迅速发展,对饲料原料的需求日益递增,很多地区玉米已供不应求。这就促使人们考虑用小麦、大麦和燕麦等来饲养家禽。但是,当这类饲料原料在家禽日粮中含量过多时,往往会造成饲料利用率差,家禽生长不良以及产生黏粪,污染环境等问题。这样,就限制了这类饲料原料在家禽日粮中的广泛应用。研究表明熏这主要与其中含有大量的非淀粉多糖(non-starchpolysaccharides熏NSP)有关。近20年来,北欧和北美一些国家对NSP的抗营养作用进行了大量研究。实践证明利用外源性NSP酶制剂可…     

奶牛瘤胃微生物非淀粉多糖酶的利用

非淀粉多糖（Non-Starch Polysaccharides,NSPs）是存在于饲料中的主要抗营养因子,不被消化道所降解,遇水形成胶态溶液,使食糜粘度增大,阻碍营养物质的消化吸收,而非淀粉多糖酶对于改善饲料品质、消除抗营养因子影响、提高动物健康有重要意义。本文主要通过瘤胃微生物非淀粉多糖酶基因的一些主要理化生特性,毒理特性来介绍瘤胃微生物非淀粉多糖和非淀粉多糖酶基因在动物生产和动物保健中的作用与利用现状,以对后续非淀粉多糖及非淀粉多糖酶基因资源的发掘与利用有所启迪。     

几种非淀粉多糖酶对肉仔鸡日粮能量的当量调控

选用木聚糖酶(x_1)、β-葡聚糖酶(x_2)、纤维素酶(x_3)和果胶酶(x_4)4种非淀粉多糖(NSP)酶,利用离体消化技术,分别研究它们对肉仔鸡日粮能量的当量调控效应。结果表明,4种NSP酶的添加水平与离体消化能(y)进行S曲线拟合的回归方程分别为:y=10.9542-0.3391/{1 exp[(x1-470.8)/115.5]}(R~2=0.9812),y=10.9453-0.3499/{1 exp[(x_2-336.9)/114.8]}(R~2=0.9851),y=10.8849-0.2733/{1 exp[(x_3-308.0)/88.2]}(R2=0.9805),y=10.8450-0.2236/{1 exp[(x_4-543.5)/104.4]}(R2=0.9875);对日粮能量调控效应的主次顺序为木聚糖酶>β-葡聚糖酶>纤维素酶>果胶酶。     

非淀粉多糖酶在仔猪高次粉饲粮中的应用研究

选择72头体质量为18kg左右的杜×长×大三元杂交猪,按饲养试验要求随机分成3组,每组3个重复,每个重复8头,母猪与去势公猪各半。其中对照组饲喂玉米饲粮,试验1组和2组分别饲喂0和0.15%NSP酶的高次粉饲粮。试验结果表明,次粉取代部分玉米,仔猪日增质量和采食量均下降,但差异不显著;料重比提高了4.68%,每千克增质量饲料成本降低了3.50%;仔猪肝脏相对质量降低了11.36%,胃、肠和胰的相对质量分别提高了10.81%、8.26%和5.88%,对心脏和肾脏无显著影响;对血钙、血磷、尿素氮和谷丙转氨酶(GPT)无显著影响;血糖、总蛋白、谷草转氨酶(GOT)、生长激素(GH)和胰岛素分别下降了8.81%、11.49%、35.84%、19.75%和12.74%。试验2组与对照组相比,日增质量和采食量分别提高了6.76%和2.22%;料重比降低了4.26%,每千克增质量饲料成本降低10.50%;总蛋白和GH分别提高了13.76%和24.69%,血糖、GPT和胰岛素略有上升,但差异不显著;血钙,血磷、尿素氮和GOT分别下降了7.45%、12.50%、14.26%和37.14%,内脏相对质量无显著变化。在高次粉饲粮中添加NSP酶显著改善了仔猪的生长性能,日增质量和采食量分别提高了15.26%和5.34%;料重比下降了8.54%;仔猪胃、胰脏和小肠的相对质量分别降低了8.54%、11.11%和8.47%,肝脏的相对质量提高了14.87%,对心脏和肾脏的相对质量无显著影响;同时,血液中的血糖、总蛋白、GH和胰岛素的含量升高了13.28%、28.52%、55.38%和21.19%,GPT虽有所上升,但差异不显著;血钙、血磷、尿素氮和GOT分别下降了4.49%、10.85%、17.45%和2.03%。     

饲用酶制剂作用的分子营养学机理与加酶日粮ENIV系统的分子生物学基础

酶制剂在饲料中添加的研究和应用是目前生物技术在饲料工业中应用最受关注的领域，华南农业大学最近几年的5篇博士论文也从不同方面讨论了饲料酶作用的机理（沈水宝，2002；于旭华，2004；黄燕华，2004；左建军，2005；谭会泽，2006）。从全球范围来看，大约65％的含有黏性谷物的家禽饲料中添加了饲料酶制剂（Sheppy，2004）。许多研究表明，饲用酶制剂，特别是非淀粉多糖酶能提高畜禽生产性能。进一步的研究发现，非淀粉多糖酶可以提高营养物质的消化率，例如提高回肠氨基酸表观消化率，而且肠系膜静脉血清总氨基酸的含量显著上升。但是，非淀粉多糖酶在提高肠道可利用氨基酸的同时，是否能提高氨基酸转运蛋白的基因表达？这是饲用酶制剂发挥作用的分子生物学基础。Kaput等（2004）指出，日粮的化学组成可以直接或间接影响动物的基因表达。     

非淀粉多糖酶对体外养分消化和肉鸡生长性能的影响

文章旨在研究两种非淀粉多糖(NSP)酶对肉仔鸡饲粮体外消化率和生长性能的影响。体外模拟消化试验中,采用单因素完全随机设计,分为3个处理组(基础饲粮,基础饲粮+酶A,基础饲粮+酶XB),每个处理5个重复,每个重复1个模拟器。添加酶A和酶XB两种酶制剂显著提高肉仔鸡基础饲粮干物质消化率、粗蛋白质消化率、总能消化率和体外消化能(P<0.05)。饲养试验选择320只1日龄科宝肉仔鸡,随机分为4个日粮处理组,每组8个重复,每个重复10只鸡,分别饲喂正对照组(PC,组1)、负对照组(NC,代谢能较PC低0.63 MJ/kg,组2)、NC+酶XB(组3)和NC+酶A(组4),分0～21 d和22～42 d两期进行。研究结果表明:与组1相比,组2的22～42 d及0～42 d平均体增重显著降低(P<0.05);组2在0～21、22～42 d和0～42 d的料重比均显著高于组1(P<0.05);组3的肉仔鸡体增重在0～21 d和22～42 d均有所改善,全期(0～42 d)组3平均体增重较组2提高47.1 g/只,但未达到显著性水平(P>0.05)。添加NSP酶可显著改善饲粮的体外消化性能,并在一定程度上提高肉仔鸡的体增重。就本研究结果而言,体外试验较准确地评定了两种商品酶制剂产品的效价。     

Performance and nutrient balance in growing swine fed low-protein diets supplemented with amino acids and potassium

Five experiments, using 216 barrows and gilts (initial weight 19.9 to 23.7 kg), were conducted to evaluate the effects of improving amino acid balance by supplementing low-protein corn-soybean meal diets with essential amino acids. Three experiments were growth studies lasting approximately 3 wk, and the other two were 4-d metabolism trials. The control diets in each of the experiments were formulated to contain .80% lysine and contained approximately 17% CP. The other diets were formulated from a basal diet containing a 10.9% CP, fortified corn-soybean meal mixture, which included crystalline L-lysine.HCI, L-tryptophan, L-threonine, L-isoleucine, DL-methionine and L-valine to correct amino acid deficiencies. Nonessential N (glutamic acid or urea) also was added to some of the diets to increase the CP equivalent to 12 or 13%. Supplemental K (as a salt of bicarbonate or glutamate) was included in selected diets to increase the K concentration to the same level as that of the control diet. Growth rate of pigs fed the basal diet was similar (P greater than .05) to that of the control diets in only one growth study. Added glutamic acid and urea did not improve either growth rate or N retention. Added K improved K digestibility but did not increase K retention, N retention or growth rate. Improving amino acid balance by adding essential amino acids to low-protein diets did not benefit performance beyond that of a typical corn-soybean meal diet. Under our conditions, K, N, and nonessential N were not limiting.     

Effects of thermostable phytase supplemented in diets on growth performance and nutrient utilization of broilers

Phytase is an enzyme that has the ability to release phosphorous (P) from phytate by hydrolyzing inositol-phosphate linkages. Recently, thermostable phytases have gained great consideration because the reduction in phytase activity was found when exposed to heat during feed pelleting. In this study, the effects of the granular thermostable phytase (Aspergillus niger) on growth performance and nutrient utilization of broilers were investigated. A total of 96 21-day-old Arbor Acres broilers were randomly distributed into six treatments including basal diet (control) and basal diet supplemented with 500, 1,000, 2,000, 4,000, 8,000 U of phytase/kg. In general, the metabolizable energy (ME) and the apparent and true availability of dry matter (DM), organic matter (OM), ether extract (EE), crude protein (CP), and amino acids (AA) showed both linearly (p < .01) and quadratically (p < .01) increase with increasing levels of phytase in the diet. Additionally, diet supplementation with phytase could improve (p < .05) body weight (BW), average daily gain (ADG), and feed/gain (F/G) on day 42 compared with the control. The results suggested that diet supplementation of the granular thermostable phytase in the crumbled pellets could improve chicken growth performance and nutrient utilization.     

母猪维生素营养需要研究进展

繁殖是母猪生命周期中最重要的阶段之一,也是种猪生产中最关键的环节。因此,母猪营养物质需要一直是猪营养研究领域的重点、难点和热点。本文对近年来母猪维生素营养需要研究进行综述。     

Comparative feeding value of supplemental fat in finishing diets for feedlot steers supplemented with and without monensin

Two comparative slaughter trials and a metabolism trial were conducted. Treatments consisted of: 1) 0 fat, 0 monensin; 2) 4% yellow grease, 0 monensin; 3) 0 fat, 33 mg/kg monensin and 4) 4% yellow grease, 33 mg/kg monensin. Trial 1 involved 104 crossbred beef steers (267 kg) in a 140-d comparative slaughter trial. There were no interactions (P greater than .20) between supplemental fat and monensin on steer performance. Monensin supplementation decreased rate of weight gain (P less than .10) and feed intake (P less than .05) with no effect on energy value of the diet (P greater than .20). Fat supplementation increased (P less than .01) rate of weight gain 12.5% and increased the net energy for maintenance (NEm) and net energy for gain (NEg) value of the diet 8.5 and 9.4%, respectively. Trial 2 involved 154 Holstein steers (290 kg) in a 94-d comparative slaughter trial. There were no interactions between supplemental fat and monensin (P greater than .20). Monensin supplementation did not affect rate or composition of gain (P greater than .20), but supplementation reduced (P less than .05) feed intake and feed required per unit weight gain 3.6%. Fat supplementation increased (P less than .01) fat and energy gain 12.5 and 10.3%, respectively, and the NEm and NEg content of the diet 7.5 and 8.4%, respectively. Trial 3 utilized four crossbred beef steers (220 kg) with cannulas in the rumen, proximal duodenum and distal ileum. There were no interactions between supplemental fat and monensin with respect to site of digestion (P greater than .20). Supplemental fat did not affect (P greater than .20) organic matter, starch, fiber or N digestion. Intestinal digestibility of fat averaged 77.3%. Monensin increased (P less than .10) intestinal digestibility of fat 7.4%. There were negative associative effects between supplemental fat and monensin on ruminal acetate:propionate ratios and estimated methane production. It was concluded that the feeding value of feed fat is underestimated in tables of feed standards currently in use, and that the net effects of monensin on these estimates are additive.     

Rearing conditions influence nutrient availability of plant extracts supplemented diets when fed to broiler chickens

The effects of a standardised mixture of essential oils, including 5% carvacrol, 3% cinnamaldehyde and 2% capsicum (XT 6930; Pancosma S.A), on dietary apparent metabolisable energy corrected for nitrogen retention (AMEn), nutrient digestibility and mucin secretions, measured as sialic acid (SA) were investigated in broilers fed on the same diet but reared under different conditions, that is, cages and floor pens littered with wood shavings used in previous broiler study. The use of XT reduced (p < 0.05) nitrogen digestibility (0.585 vs. 0.544) and tended (p = 0.072) to reduce dry matter digestibility (0.733 vs. 0.717) of the diet when fed to birds reared in cages. However, XT supplementation improved (p < 0.05) fat digestibility (0.844 vs. 0.862) and tended (p = 0.093) to increase AMEn (14.01 vs. 14.25 MJ/kg DM) of the same diet when fed to broilers reared in floor pens. Essential oils supplementation tended (p = 0.059) to increase the secretion of SA, when fed to birds reared in cages (11.24 vs. 14.18 μg), but did not influence (p > 0.05) the SA secretion from birds reared in floor pens. The results obtained from the cage study tend to be the opposite of those obtained from the floor pen study. This suggests that the efficiency of dietary plant extracts may be influenced by the rearing/hygienic conditions of poultry. Based on the overall results, it can be concluded that information on rearing conditions should be taken into account for more complete interpretation of the experimental data emanating from experiments involving use of essential oils typified by those considered in this study.     

家禽磷营养研究进展与应用

磷是饲料配方成本中处于第三位的营养素。磷资源不足与养殖业磷需求量增加形成尖锐矛盾。节约有限的磷资源,提高现有磷源利用率成为饲料和养殖业发展的必然趋势。文中从以下4个方面对家禽磷营养进行综述:磷的来源与效价,家禽磷需要量,内源(动物肠道)植酸酶、植物植酸酶和微生物植酸酶的关系,配方设计中的节磷措施。