挤压参数对组织化大豆蛋白糊化度的影响

本试验以单螺杆挤压膨化机为试验设备对豆粕进行膨化试验,研究工艺参数对膨化指标的影响规律。试验结果表明,豆粕含水率、膨化机螺杆转速和机筒温度对豆粕糊化度具有显著的影响。机筒温度是影响糊化度的主要因素。采用优化方法对试验参数进行了优化计算,当膨化机转速为235 r/min、机筒温度为124℃、豆粕含水率为21%时,膨化机工作性能综合指标达到最优。     

单螺杆挤压机相关参数的优化

本试验采用SDP-45小型单螺杆挤压膨化机,通过三因子五水平二次通用旋转组合设计,研究了豆粕挤压膨化系统诸参数(物料含水率、螺杆转速、机筒温度)对产品容重的影响规律,并优化了挤压膨化系统的最佳参数.结果表明,影响产品容重的豆粕挤压膨化系统诸因素主次排序为:机筒温度>物料含水率>螺杆转速.其较优组合为螺杆转速为240 r/min、机筒温度为130℃、物料含水率为28%.     

挤压膨化与后添加技术在饲料工业中的应用(3)

5乳猪料的挤压膨化工艺传统的膨化机为挤压机,是利用挤压腔内的高温、高压和高剪切的作用使被处理物料在理化性质、质构上发生变化。由于它的挤压条件强烈、产量小、能耗高,目前饲料行业仅用于原料处理(如全脂大豆膨化、全脂米糠膨化、羽毛膨化等)、饼粕脱毒(如棉饼粕、菜籽粕及蓖麻粕脱毒等)、宠物饲料及水产饲料的生产,而无法应用推广到畜禽饲料的生产。另一方面,我国乳猪料是以玉米和豆粕为主,而乳猪的生理消化功能不健全,对植物蛋白利用率很差,特别是大豆或豆粕中致使乳猪下痢的真正抗营养因子betaglycimin和betaconglycimin,在普通加工…     

挤压膨化对血粉消化率的影响

应用P400G干法膨化机，分别探讨挤压膨化加工中血粉含水率、螺杆转速及出料模孔直径对血粉消化率的影响规律，试验结果表明，挤压膨化加工具有改善血粉品质、提高血粉消化率的特点。     

单螺杆和双螺杆挤压膨化机的一般比较

随着双螺杆挤压膨化机应用领域的拓宽。双螺杆挤压膨化机也开始用于宠物、水产、特种经济动物和幼畜哺乳期等饲料加工生产。然而。我国现有的饲料加工仍以单螺杆挤压膨化机为主。主要是由于进口双螺杆挤压膨化机成本太高。而国产双螺杆挤压膨化机技术性能和质量等方面尚有不足，也缺乏针对饲料工业特点应用的大产量机型。尽管从单螺杆和双螺杆的挤压膨化原理及机体结构分析就可看出双螺杆挤压膨化机具有明显的优势并具有更好的性价比。但相对于食品加工业的应用仍要逊色得多。近年来。随着国内企业引进、消化吸收国外先进技术。国产双螺杆挤压膨化机生产技术水平不断提高。特别是针对水产饲料生产推出了双螺杆挤压膨化专用机型，使得用投资单螺杆挤压膨化机的资金同样可以选用双螺杆机型。     

不同温度挤压膨化全脂大豆对肉仔鸡生产性能和养分利用率的影响

为评定膨化全脂大豆的营养价值及膨化加工的适宜条件参数,用肉仔鸡进行了为期４９天的饲养试验和一个预试及正试期各３天的交叉代谢试验。饲养试验选用４０４只１日龄哈巴德母系公雏肉仔鸡,分成４组,每组１０１只。以豆粕＋豆油日粮为对照,分别用北京建中机器厂“Ｂ９９－１”干法挤压膨化机生产的１３０、１４０和１５０℃膨化全脂大豆替代对照日粮中部分豆粕和全部豆油。于饲养试验的第４２天在每个处理中选４笼鸡进行代谢试验,喂给与饲养试验相同的日粮,用全收粪法测定养分消化率。结果表明,在螺旋转速为４５０～５５０ｒｐｍ、大豆水分为１３．１％时,“Ｂ９９－１”膨化机对全脂大豆的适宜膨化温度为１４０～１５０℃。在此条件下,用膨化全脂大豆替代日粮中部分豆粕和全部豆油,可使肉仔鸡全程日增重提高１．９％～２．３％,饲料转化率提高３．４％～４．４％（Ｐ＜０．０５）,氮表观消化率提高４．５％～５．１％,脂肪表观消化率提高５．３％（Ｐ＜０．０５）～５．８％（Ｐ＜０．０５）,日粮部分氨基酸利用率略有改善。     

膨化加工对全脂大豆养分含量和抗营养因子的作用

为评定膨化全脂大豆的营养价值及干法膨化的适宜条件参数，测定了“Ｂ９９－１”干法挤压膨化机生产的３个膨化温度的全脂大豆、生大豆粉和湿法膨化全脂大豆的常规养分、抗营养因子含量、蛋白溶解度、蛋白分散指数和淀粉糊化度。结果表明，生大豆经膨化后，水分和粗纤维分别减少４７％和３６％，总能、蛋白质和钙稍有升高，脂肪含量无变化。干法膨化温度和膨化方法对氨基酸含量和脂肪组成影响很小，随膨化温度升高，赖氨酸含量稳定在２．３７％。膨化加工对全脂大豆理化性状和抗营养因子有重要影响，淀粉糊化度提高约５倍，蛋白分散指数和溶解度大幅度降低，脲酶活性（△ｐＨ）由生大豆的４．４２降低到１５０℃挤压膨化的０．０２和湿法膨化的０．０４，对胰蛋白酶抑制因子的破坏程度由１３０℃干法膨化的８５．６％提高到湿法膨化的９１．５％。经过几年的努力，国产膨化机对全脂大豆有良好的生产性能，“Ｂ９９－１”干法挤压膨化机在螺旋转速为４５０～５５０ｒｐｍ时，对全脂大豆的适宜膨化温度为１４０～１５０℃。     

基于BP神经网络的变压器内部故障保护

本文研究了基于BP神经网络方法的变压器内部故障保护。运用MATLAB/SUMILINK对变压器励磁涌流、励磁涌流与故障电流的差异进行了数字仿真。利用MATLAB的人工神经网络工具箱,建立了BP神经网络模型,对励磁涌流和故障电流的样本进行训练及测试并对训练好的网络进行验证。表明BP神经网络可以较为正确地区分励磁涌流和故障电流,用于变压器内部故障保护。     

基于参数自调整模糊PID算法的饲料膨化机控制仿真分析

为了能够提高饲料膨化的质量,利用参数自调整模糊PID控制算法对其温度进行控制。首先,分析了饲料膨化机温度控制的基本要求;其次,研究了饲料膨化机温度模糊参数自调整PID控制的基本思想;然后,讨论了饲料膨化机温度模糊参数自调整PID控制器的输入和输出;最后,进行了仿真分析,仿真结果表明该方法具有较高的鲁棒性。     

膨化技术及其在饲料中的应用

1膨化与膨化技术1.1 膨化的概念及膨化技术发展的历史沿革 膨化是将物料加湿、加压、加温调质处理,并挤出膜孔或突然喷出压力容器,使之因骤然降压而实现体积膨大的工艺。膨化加工应用于人的食品制造业已有50多年的历史(Ferket,1991),其间膨化技术及相应的机械设备经过许多历史变迁,膨化加工的方法由干法挤压到湿法挤压再发展到气体热压,加工机械从单螺旋到双螺旋,加工方式从间歇到连续。60年代初,联合国儿童基金会(UNICEF)组织膨化机生产商和科学家进行了利用膨化技术生产高质量植物蛋白的大量研究,不久该技术得到了广泛的应用,使发展中国家婴儿的成活率和母亲的体质有了很大的提高(Mustakas等,1964)。在UNICEF这一行动影响和鼓励下,涌现了大批的膨化机生产商,营养、食品等行业的许多科学家对每种加工方式甚至每种机械设备的条件参数进行了大量的研究,膨化技术日趋完善。随着膨化机生产商的资本积累和行业竞争加剧,膨化机构造不断简化,操作更加方便,价格不断下跌,产量的控制更加灵活,完整的技术服务体系亦随之建立。这些变化使膨化设备在发展中国家小型的食品加工厂和全脂大豆粉生产厂得以应用。目前,膨化技术已具有下面公认的优点:     

鹅和鸡4种常用饲料原料的代谢能比较

本试验旨在比较鹅和鸡常用饲料原料的代谢能差异.选用体重为(3.76±0.23)kg的成年扬州鹅(公)和体重为(2.57±0.17)kg的成年新扬州鸡(公)各10只,采用Sibbald真代谢能法测定玉米、豆粕、稻谷、麦麸4种常用饲料原料的代谢能值,内源能测定采用饥饿法.结果表明:玉米、豆粕的表观代谢能(AME)鹅与鸡差异不显著(P＞0.05),真代谢能(TME)鹅显著低于鸡(P＜0.05);而稻谷、麦麸的AME鹅显著高于鸡(P＜0.05),TME鹅与鸡差异不显著(P＞0.05).每小时内源能排出量,除强饲豆粕条件下鹅略高于鸡但差异不显著外(P＞0.05),强饲其他3种饲料条件下,鹅均显著高于鸡(P＜0.05).由此表明,鹅的饲料代谢能与鸡的并不完全相同,部分饲料的代谢能鹅和鸡之间存在显著差异,并且鹅的内源能排出量高于鸡.     

Additivity of values for apparent and standardized ileal digestibility of amino acids in mixed diets fed to growing pigs

The objective of this experiment was to determine whether the digestibility of CP and AA in a mixed diet fed to growing pigs is better predicted when based on standardized ileal digestibility coefficients (SID) or apparent ileal digestibility coefficients (AID). Eight growing pigs (initial BW = 92.1 +/- 3.19 kg) were surgically equipped with a T-cannula in the distal ileum and arranged in an 8 x 8 Latin square design with eight diets and eight periods. Three of the diets contained corn, soybean meal (SBM), or canola meal (CM) as the sole source of CP and AA. Four mixed diets also were formulated using corn and soybean meal (CS); corn and canola meal (CCM); soybean meal and canola meal (SCM); or corn, soybean meal, and canola meal (CSCM). A N-free diet was used to measure the basal ileal endogenous losses (IAAend) of CP and AA. Pigs were fed each of the eight diets during one 7-d period, and ileal digesta were collected during two 10-h periods on d 6 and 7. The AID values were calculated for CP and AA in all diets, except the N-free diet. By correcting the AID for IAAend, the SID for CP and AA in each of the seven protein-containing diets were calculated. As expected, the AID for CP and the majority of AA were greater in SBM than in corn and CM (P < 0.05); however, the SID for CP and most AA did not differ between corn and SBM. For the majority of the AA, SID were less (P < 0.05) in CM than in the other two ingredients. Using the AID and the SID that were measured for CP and AA in corn, SBM, and CM, the AID and the SID in the four mixed diets were predicted and compared with the measured values for these diets. For the three mixed diets containing corn, the measured AID for CP and most AA were greater (P < 0.05) than the predicted AID, but with a few exceptions, no differences between predicted and measured values for SID were observed. For the diet based on SCM, there were no differences between predicted and measured values regardless of the procedure used, except for the AID of Ser. The results of this experiment demonstrate that the digestibility coefficients for a mixed diet containing low-protein feed ingredients, such as corn, are more accurately predicted using SID than AID.     

Bioavailability of threonine in soybean meal for rats and chicks.

The bioavailability of threonine in soybean meal and the effects of the excess amino acids in soybean meal on the estimate were measured using rats and chicks in slope-ratio assays. In Exp. 1, a corn-based diet containing .23% threonine was supplemented with 0 to 45% L-threonine in .05% increments. The growth rate of weanling rats fed these diets increased quadratically (P less than .001) with L-threonine addition, the increase being essentially linear up to the .10% addition. In Exp. 2, the basal diet was supplemented with 0, .025, .050, .075, or 100% threonine from L-threonine, simulated soybean meal (a mixture of crystalline amino acids with a pattern designed to simulate soybean meal), or soybean meal. Regressions of partitioned weight gain and body N gain of rats vs supplemental threonine intake were calculated for each source using multiple regression. Slope ratios (soybean meal:L-threonine) were .91 for weight gain and .92 for body N gain. The additional amino acids in simulated soybean meal did not affect the estimate. For Exp. 3, a corn-soybean meal-based diet containing .48% threonine was supplemented with 0 to 60% L-threonine in .10% increments. The growth rate of broiler chicks fed the diets increased quadratically (P less than .001) with L-threonine addition. The increase was essentially linear up to the .10% addition. In Exp. 4, the basal diet was supplemented as in Exp. 2. Regressions of partitioned weight gain of chicks vs supplemental threonine intake were calculated for each source. The slope ratio for soybean meal:L-threonine was 1.03; however, the model exhibited fundamental invalidity and therefore the estimate should be interpreted with caution. The additional amino acids in the simulated soybean meal did not affect the value.     

Effect of enzyme preparation containing xylanase and beta-glucanase on performance of laying hens fed wheat/barley- or maize/soybean meal-based diets

1. A commercial enzyme preparation (Quatrazyme HP) containing xylanase and beta-glucanase was examined in two laying hen experiments with wheat/barley- or maize-based diets. The activities of other enzymes were measured also. Starch, cell wall contents and effects of Quatrazyme HP on in vitro viscosity of wheat, barley, maize and soybean meal were determined. 2. In the first experiment, 90 ISA Brown laying hens at 28 weeks of age were given a wheat/barley basal diet with or without 20mg of Quatrazyme HP, which provided 560 and 2,800 IU of xylanase and beta-glucanase/kg diet. In the second experiment, 66 ISA Brown laying hens at 45 weeks of age were given a maize/soybean meal basal diet with or without 20 mg of Quatrazyme HP/kg diet for 9 weeks. Egg production, egg weight, egg mass, feed conversion ratio and change in body weight were recorded as response criteria. 3. There was a significant improvement in feed conversion ratio with enzyme supplementation. Birds given an enzyme-supplemented diet gained 86 g while those fed on the unsupplemented diet lost 103 g of their body weight by the end of the experiment. 4. The enzyme preparation did not affect either egg production, egg weight or egg mass of birds fed on the maize/soybean meal diet. However, a significant improvement in feed conversion ratio was detected. Birds on either the supplemented or unsupplemented diet exhibited an increase in their body weight at the end of the experiment. 5. Addition of xylanase and beta-glucanase decreased in vitro viscosity of wheat, barley, maize and soybean meal. This effect was greater for wheat and barley than for maize and soybean meal. 6. It was concluded that the beneficial effect of using an enzyme preparation containing xylanase and beta-glucanase is not limited to wheat/barley-based diets but also occurs with maize/soybean meal-based diets.     

固态发酵菜籽粕对肉仔鸡生长性能、免疫功能及消化酶活性的影响

本试验旨在研究用固态发酵菜籽粕替代部分豆粕对肉仔鸡生长性能、免疫功能及消化酶活性的影响.试验选用1日龄爱拔益加肉仔鸡180羽,随机分为3组,每组6个重复,每个重复10羽,分别饲喂玉米-豆粕型基础饲粮(豆粕对照组)以及用未发酵菜籽粕(菜籽粕组)或固态发酵菜籽粕(发酵菜籽粕组)等氮替代基础饲粮中25％豆粕的饲粮.试验期6周.结果表明:发酵菜籽粕组较菜籽粕组可显著提高肉仔鸡全期的平均日增重(P＜0.05),而发酵菜籽粕组肉仔鸡平均日增重比豆粕对照组稍高,但差异不显著(P＞0.05).21日龄时,与豆粕对照组相比,发酵菜籽粕组显著提高了肉仔鸡的脾脏指数、胸腺指数及十二指肠、空肠、回肠和盲肠的蛋白酶、淀粉酶和脂肪酶活性(P＜0.05);42日龄时,菜籽粕组较豆粕对照组显著提高了肉仔鸡的脾脏指数(P＜0.05),发酵菜籽粕组显著提高了十二指肠、空肠、回肠和盲肠的蛋白酶、淀粉酶和脂肪酶活性(P＜0.05).由此可见,固态发酵菜籽粕等氮替代基础饲粮中25％的豆粕具有提高肉仔鸡生长性能、免疫功能和肠道消化酶活性的作用.     

仿生消化法测定猪饲料原料还原糖释放量的重复性和可加性研究

本试验旨在建立单胃动物仿生消化系统模拟猪饲料原料消化后还原糖释放量的测定方法,为饲料养分生物学效价的评估提供参考。还原糖释放量与上样量的线性关系研究以玉米-豆粕混合物(75%玉米+25%豆粕)为研究对象,上样量设0.2、0.4、0.6、0.8和1.0 g 5个处理,每个处理4个重复,每个重复1根消化管;方法的重复性检验以玉米-豆粕混合物、大麦、花生粕和米糠为研究对象,每个样品设3个批次,每个批次4个重复;方法的可加性检验设19个处理,其中处理1~7分别为玉米、大麦、高粱、大豆粕、花生粕、棉籽粕和米糠,处理8~19为2种或2种以上饲料原料按不同比例组合制备的12种混合饲料,每个处理4个重复,每个重复1根消化管,在仿生消化系统中模拟猪消化后测定各处理的还原糖释放量。结果表明:上样量在0.2~0.8 g时,还原糖总释放量与上样量呈显著的线性关系(R2=0.999 2),还原糖相对释放量在559.56~582.70 mg/g DM变化,变异系数为1.66%,而上样量为1.0 g时,还原糖相对释放量比上样量为0.2~0.8 g时的平均值下降5.37%;3个批次的大麦、花生粕、米糠和玉米-豆粕混合物的还原糖释放量的批内变异系数、批间变异系数和总变异系数均不大于1.68%,批间最大相对偏差分别为0.68%、1.50%、1.39%和0.29%;12种混合饲料还原糖释放量的实测值显著高于计算值(P0.05),而还原糖释放量的计算值与实测值的线性回归模型与y=x相重合(截距P=0.480 5;斜率P=0.514 1)。由此得出,当上样量在0.2~0.8 g时,上样量与还原糖释放量呈显著线性关系;仿生消化法测定猪饲料原料还原糖释放量的重复性和可加性满足定量分析的基本要求。     

Determination of apparent ileal amino acid digestibility in rapeseed meal and cake processed at different temperatures using the direct and difference method with growing pigs.

Studies were conducted with ten barrows, average initial body weight 34.5 +/- 2.1 kg, fitted with a T-cannula at the distal ileum, to study the accuracy of determination of the apparent ileal digestibility (AID) values of crude protein (CP) and amino acids (AA) in rapeseed meal and cake and the effects of processing, using the difference method. Five corn starch-based diets in the studies were formulated to contain 17.7% CP and based on soybean meal, prepress-extraction rapeseed meal, prepress-extraction rapeseed meal plus soybean meal, high-temperature press rapeseed cake plus soybean meal, or low-temperature press rapeseed cake plus soybean meal as the sole source of dietary protein. The design was an incomplete Latin Square involving two three-week periods and five-treatments. It was found that the AID values of CP and most AA determined with the difference or direct method were significantly lower in rapeseed meal or cakes than soybean meal. The AID values of CP and most AA in prepress-extraction rapeseed meal, high-temperature press or low-temperature cakes determined with the difference method were no difference from those in prepress-extraction rapeseed meal determined with the direct method. The AID values of CP and AA in rapeseed meal and cake determined with the difference method were accurate, when the contribution of CP and AA from rapeseed was more than 50%. The AID values of CP and AA (especially lysine) were lower in the high-temperature press rapeseed cake than in the low-temperature press cake or the prepress-extraction meal.     

双低菜籽粕在妊娠母猪日粮中适宜添加量研究

选初产妊娠母猪（长白（♂）与八眉猪（♀）杂交一代母猪）40头,随机分四组进行饲养试验,试验组日粮中分别用6％、9％和12％的双低菜籽粕取代日粮中的豆粕,并与等能量、等蛋白的豆粕日粮作对照。结果表明：用12％双低菜籽粕取代豆粕蛋白饲喂妊娠母猪,对妊娠母猪产仔数和仔猪初生重测定,试验组间差异不显著（P〉0．05）;并通过对...     

不同方法测定瘤胃非降解蛋白质小肠消化率及相关性分析

本试验分别采用移动尼龙袋法、改进三步体外法、原始三步体外法和酸性洗涤不溶氮(ADIN)估测法测定13种精料的瘤胃非降解蛋白质(RUP)小肠消化率,并对移动尼龙袋法与其他方法的测定结果进行相关性分析,同时对常规营养成分和RUP小肠消化率作回归分析,旨在寻找替代移动尼龙袋法测定RUP小肠消化率更简单快速的方法.试验采用单因素试验设计,选取3头装有永久瘤胃瘘管和十二指肠T型瘘管的奶牛.结果表明:移动尼龙袋法测得的豆粕、棉籽粕、菜籽粕、葵花粕、芝麻粕、玉米胚芽粕、玉米、米糠、米糠粕、米糠饼、大麦、麦麸和玉米麸质饲料的RUP小肠消化率分别为98.13％、87.37％、88.47％、82.60％、85.73％、75.40％、93.23％、69.27％、77.83％、92.10％、91.27％、72.37％和79.03％.改进三步体外法测定结果与移动尼龙袋法测定结果的相关系数为0.8383;原始三步体外法测定结果与移动尼龙袋法测定结果的相关系数为0.7899;ADIN估测法预测结果与移动尼龙袋法测定结果无显著相关(P＞0.05);饲料RUP小肠消化率与饲料常规营养成分含量显著相关(P＜0.05).改进三步体外法比原始三步体外法替代移动尼龙袋法测定饲料RUP小肠消化率效果更好.应用体外法替代移动尼龙袋法测定蛋白质饲料RUP小肠消化率比测定能量饲料RUP小肠消化率效果更好.用饲料的常规营养成分含量可较好地预测RUP小肠消化率.