小麦日粮中添加木聚糖酶对肉仔鸡生产性能和养分消化率的影响

试验用360只爱拔益加肉仔鸡,研究了在用小麦全部取代玉米配制的日粮中,添加木聚糖酶对肉仔鸡的生产性能和养分消化率的影响。试验结果表明:小麦全部取代玉米后,肉仔鸡的小肠食糜粘度、耗料增重比和死淘率显著升高,蛋白质、脂肪、淀粉的消化率及能量的利用率均降低;而在此小麦日粮中添加木聚糖酶后,耗料增重比和小肠食糜粘度显著降低(P<0.05),死淘率降低71.9%,能量利用率和蛋白质、脂肪、淀粉的消化率显著提高(P<0.05)。     

溢酸宝对仔猪日粮营养物质消化率影响的探讨

以５头断奶仔猪进行两期消化试验。第一期为对照组，饲喂基础日粮，第二期为试验期，饲喂添加０．１５％溢酸宝的基础日粮，采用内源指示剂法测定日粮中营养物质消化率，试验结果，试验期日粮中粗蛋白，总氨基酸，粗脂肪。粗纤维，钙和磷的表观消化率分别为８６．６１％、８４．６６％、６８．０３％、２７．１８％、８４．７１％和６３．３２％。比对照期分别提高９．３７％（Ｐ〈０．０１），９．７６％（Ｐ〈０．０１），１１．０     

α-乳白蛋白对婴幼儿生长发育的影响研究进展

乳白蛋白是哺乳动物和人类乳汁中的一种钙结合蛋白,占母乳总蛋白质的20%～25%,其结构与溶菌酶相似,含有丰富的赖氨酸、亮氨酸、异亮氨酸、半胱氨酸和色氨酸等必需氨基酸,具有多种营养保健功能,在食品生产中具有广阔的应用发展前景,受到大众广泛的关注。目前,我国6月龄以下纯母乳喂养率低,婴幼儿配方乳粉与母乳对婴儿健康生长至关重要。大量研究表明α-乳白蛋白能够促进神经发育、调节睡眠节律并改善抑郁情绪;还能够提高铁和锌的吸收利用率、促进消化道功能完善和胃肠道发育,对于婴幼儿早期的营养至关重要。本文从α-乳白蛋白的氨基酸组成和结构,对婴幼儿体格、大脑神经以及胃肠道发育的影响等方面综述了国内外相关研究进展,以期为婴幼儿配方乳粉的升级和“母乳化”的推广应用提供理论参考。     

3个肉兔品种对不同水平粗纤维饲粮养分消化率影响的研究

为研究不同品种肉兔对不同粗纤维水平饲粮养分消化率的影响,试验选择四川白兔、齐兴肉兔和新西兰白兔各12只,每个品种随机分成2组,每组6只(公母各半),分别饲喂含低粗纤维水平(12%)和高粗纤维水平(16%)的饲粮,采用全收粪法测定饲粮养分消化率。结果表明,四川白兔、齐兴肉兔和新西兰白兔对低粗纤维组饲粮(12%)粗纤维消化率存在显著差异(P0.05),四川白兔和齐兴兔消化率显著高于新西兰兔,3个品种对干物质、粗蛋白质、粗脂肪、无氮浸出物和粗灰分的消化率差异不显著(P0.05)。四川白兔、齐兴肉兔和新西兰白兔对高粗纤维组(16%)饲粮干物质、粗蛋白质、无氮浸出物和粗纤维消化率存在显著差异(P0.05),四川白兔和齐兴兔消化率显著高于新西兰,3个品种对粗脂肪和粗灰分的消化率差异不显著(P0.05)。由此可见,品种对不同水平粗纤维饲粮养分消化率存在显著差异,特别是高粗纤维饲粮,其中四川白兔和齐兴兔对高粗纤维饲粮有较高的消化率,耐粗饲性较好,而新西兰兔对高粗纤维饲粮的消化率较差,耐粗饲性较差。     

自然霉变饲粮添加酵母细胞壁对仔猪养分消化率和消化酶活性的影响

本试验旨在研究自然霉变饲粮添加酵母细胞壁(YCW)对仔猪养分消化率、肠道消化酶活性的影响。选取40头体重相近(8.32±0.49)kg健康的三元(杜×长×大)杂交仔猪,随机分为4个处理,每个处理10个重复。对照组用优质玉米和玉米蛋白粉配制基础饲粮,50%M组(玉米赤霉烯酮849.4μg/kg;伏马毒素5 661.55μg/kg;呕吐毒素1 576.80μg/kg)为霉变玉米和玉米蛋白粉替代对照组中50%的玉米和玉米蛋白粉,0.10%YCW和0.25%YCW组为50%M组基础上添加0.10%和0.25%的YCW。结果表明:自然霉变饲粮显著降低仔猪养分消化率及十二指肠和空肠淀粉酶(AMS)、胰蛋白酶(TRS)和脂肪酶活性(LPS)(P0.05);YCW显著改善仔猪养分消化率以及消化酶活性(P0.05),并具有剂量效应。由此可知,自然霉变饲粮降低了仔猪养分消化率及AMS、TRS和LPS活性,酵母细胞壁具有一定的改善和脱毒效果。     

日粮中添加豆油对肉牛瘤胃发酵及营养物质消化率影响的研究

本试验选用４ 头装有永久瘤胃和真胃瘘管的阉牛,采用４ ×４ 拉丁方设计,对照组牛饲喂基础日粮,３ 个试组在基础日粮中分别添加豆油１５０ｇ 、３００ｇ 及４５０ｇ 。探讨日粮中添加豆油对肉牛瘤胃发酵及营养物质消化率的影响。结果表明,日粮中添加豆油使瘤胃总挥发性脂肪酸（ Ｔ Ｖ Ｆ Ａ） 浓度显著下降,３ 个试验组平均总挥发性脂肪酸（ Ｖ Ｆ Ａ） 浓度比对照组下降２２ ．３７ ％ 。日粮日添加４５０ｇ 豆油使瘤胃内及全消化道干物质和有机物的消化率显著下降（ Ｐ＜ ０ ．０５） 。日粮中补充豆油时,随着添加量的增加瘤胃内及全消化道中性洗涤纤维（ Ｎ Ｄ Ｆ） 消化率呈下降趋势,而对瘤胃后 Ｎ Ｄ Ｆ 消化率无影响。日粮中补充豆油对酸性洗涤纤维（ Ａ Ｄ Ｆ） 消化率的影响与对 Ｎ Ｄ Ｆ 消化率的影响相一致。４ 个组脂肪酸表观消化率分别为６０ ．３７ ％ 、７８ ．６７ ％ 、８５ ．３５ ％ 和８７ ．８３ ％ ,随着豆油添加量的增加脂肪酸表观消化率线性提高。     

重组人乳铁蛋白对大鼠生长发育作用的实验研究

目的 研究从转基因牛乳中分离纯化的重组人乳铁蛋白是否具有促进动物生长发育的作用.方法 给大鼠灌胃重组人乳铁蛋白共8周,设低、中、高3个剂量组(0.375,0.75和2.25 g/kg BW·d)以水为对照组.检测指标包括动物体重、身长、摄食童和食物利用率.结果 高剂量组体重、身长和食物利用率指标均显著优于对照组,低、中剂量组的体格发育指标较对照组有轻度改善.结论 在本研究条件下,重组人乳铁蛋白具有促进大鼠生长发育的作用.     

发酵非常规蛋白饲料对肉仔鸡生长性能和养分消化率的影响

研究了发酵非常规蛋白饲料(后称发酵饲料)对肉仔鸡生产性能和养分消化率的影响,选用250只肉仔鸡,随机分为5个处理组,试验期6周。A组饲料为基础玉米豆粕日粮,B组添加10%未发酵饲料替代部分豆粕,处理组C、D、E分别添加发酵饲料5%、10%、15%替代部分豆粕。处理组平均日采食量、平均日增重均高于B组,与A组相比差异不显著(P>0.05),D组与A组最为接近。通过代谢试验可得出,发酵饲料与未发酵饲料相比粗蛋白质消化率显著增加(P<0.05),氨基酸消化率差异不显著(P>0.05)。因此,在发酵饲料替代10%豆粕是可行的。     

日粮纤维水平对鹅内源氨基酸排泄量和氨基酸真消化率的影响

30只42日龄鹅为试验动物,以砻糠和玉米秸秆为主要纤维源,在日粮等能量等蛋白的前提下,采用同位素示踪技术,研究了不同日粮粗纤维水平（3％、5％、7％、9％和11％）对鹅内源氨基酸排泄量和氨基酸真消化率的影响。结果表明,内源氨基酸排泄量指标,CF11组（最高）比CF3组（最低）升高了92．13％（P〈0．01）;氨基酸真消化率指标,CF11组（最低）比CF5组（最高）降低了39．88％（P〈0．01）;粗纤维水平在3％。7％范围内随粗纤维水平增加,鹅内源氨基酸排泄量有升高的趋势,但差异不显著（P〉0．05）,氨基酸真消化率较高且较稳定（P〉0．05）;粗纤维在7％-11％范围内随着粗纤维水平的增加,内源氨基酸排泄量极显著升高（P〈0．01）,氨基酸真消化率极显著降低（P〈0．01）。     

凝乳酶和热处理对干酪素消化率的影响

通过体外消化法研究干酪素生产时凝乳酶和热处理对干酪素消化率的影响.结果表明,凝乳酶抑制干酪素的胃肠消化,随着凝乳酶添加量的增加,消化率降低极显著;热处理会降低干酪素的消化率,特别是120～130 ℃会极显著降低消化率.     

茶多酚与牛奶蛋白互作对蛋白质离体消化率的影响

采用胃蛋白酶体外消化法和HPLC法测定了茶多酚与牛奶蛋白互作后蛋白质的离体消化率和几种主要儿茶素含量的变化,并用酒石酸铁比色法测定了两者互作后不同结合状态茶多酚的含量。结果表明:在牛奶蛋白含量为0.5%、茶多酚含量在0-10.0 g/kg的模拟奶茶溶液中,蛋白质的离体消化率随茶多酚浓度的增大而下降,茶多酚含量≥2.0 g/kg时牛奶蛋白的离体消化率显著降低;等体积的纯牛奶和茶水同时食用时,茶水中茶多酚含量≥2.5 g/L时牛奶蛋白的离体消化率显著降低。实验结果还表明,食用条件下茶多酚与牛奶蛋白的结合以物理结合为主,而其中EGCG和ECG 2种儿茶素与牛奶蛋白有较强的反应活性,对牛奶蛋白的离体消化率起主要影响作用。     

Effects of Dietary Crude Protein on Protein and Fat Deposition in Milk-Fed Veal Calves

Research on veal calf production has focused on maximizing lean tissue growth. Nevertheless, limited attention has been paid to the evolution of digestive and metabolic utilization of N and energy as calves get older, whereas age at slaughter increases. The objective of this study was to determine the effects of 4 concentrations of dietary crude protein (CP) content on protein and fat deposition and energy utilization in milk-fed calves at 3 stages of fattening using the balance technique combined with heat production measurements in a respiration chamber. At each stage, 16 Prim’Holstein male calves (mean body weight at each stage: 72, 136, and 212 kg) received 4 isocaloric diets with CP contents of 76, 88, 100, and 112% of a reference CP content fixed at 20% during the first stage and 19% during the 2 later stages. After 2 wk of adaptation to their respective diets and housing conditions, the calves were placed for 1 wk in an open-circuit respiration chamber for N and energy balance measurements (first 6 d) and measurement of the fasting heat production (last day). Measurements for a stage were performed over 2 periods of 4 successive weeks. There was no effect of dietary CP on digestibility during the 2 later stages, but the low-protein diet resulted in lower digestibility coefficients for dry matter, organic matter, gross energy, CP, and crude fat during the first stage. Endogenous fecal N was estimated as 2.5 g/kg of dry matter intake irrespective of stage, and metabolic urinary N was estimated at 0.07 g/kg of body weight^0.85 per day. Maximum N retention was 32.8, 40.5, and 44.0 g/d at stages 1, 2, and 3, respectively. The effect of protein intake on protein deposition was dependent on age of the calves, because the marginal efficiency of digestible protein utilization decreased from 64 to 18% as animals got older. Fat deposition decreased with increasing dietary CP content irrespective of stage. Total energy retention was not modified by dietary CP content. The composition of body weight gain was affected differently for each stage, because the protein content of body weight gain increased with increasing dietary CP content during the first stage, whereas it remained constant during the other 2 stages. Fat and energy content in body weight gain decreased with increasing dietary CP irrespective of stage. These results provide a basis for estimating protein requirement of veal calves according to a factorial approach.     

高温热处理对大豆蛋白消化利用效果的影响

为明确高温热处理杀菌工序中蛋白质热变性程度对大豆蛋白营养有效性的影响,本研究通过体外模拟婴儿消化,分析高温热处理对大豆蛋白消化利用效果的影响。结果表明：与100 ℃相比,高温热处理（超过120 ℃、20 min）后的大豆蛋白易生成更多更低分子质量的酶解产物;与此同时,这种高温热处理也导致体系内的氨基酸大量被破坏,尤其是胱氨酸损失较多（约48%）;因此严重破坏了大豆蛋白氨基酸合理的模式,降低了大豆蛋白本身的营养有效性。     

核桃乳中掺大豆乳的鉴别研究

建立了一种用高效液相色谱法检测核桃乳中掺有大豆乳的方法。样品用甲醇超声提取20 min,料液比为1:9 （体积比）,在4000 r/min条件下离心20 min。使用Promosil C18（4.6 mm×150 mm,5 μm）色谱柱,以甲醇-水作流动相进行梯度洗脱,检测波长为258 nm。结果表明,通过对大豆异黄酮的检测,可以有效地鉴别核桃乳中是否掺有大豆乳;大豆苷和染料木苷的线性范围为0.3~200 μg/mL,大豆苷元和染料木素的线性范围0.1~150 μg/mL。线性相关系数在0.9968和1.0000之间,样品加标回收率为80.73~116.44%,相对标准偏差≤4.62% (n=5),检测限为0.03~0.1 μg/mL,该方法快速、灵敏、简便易行。     

不同奶茶体系共存物对大豆分离蛋白性质的影响

为解决大豆分离蛋白在奶茶体系中稳定性较差的问题,本文探究了奶茶体系中共存物(酪蛋白、单甘脂、奶油、茶多酚、糖类、盐类、奶粉、红茶粉)对大豆分离蛋白乳化性(乳化活性和乳化稳定性)的影响。并通过乳状液ζ-电位和粒径的测量,探讨奶茶体系共存物与大豆分离蛋白相互作用及对其乳化性的影响规律。结果表明:在酪蛋白、茶多酚、乳糖添加量分别为0.2%、0.06%、0.1%时大豆分离蛋白乳化活性最小;在单甘脂、卡拉胶、氯化钠、脱脂奶粉添加量分别为0.15%、0.02%、0.02%、2%时大豆分离蛋白乳化稳定性最大;在乳糖添加量为0.1%时大豆分离蛋白乳化稳定性最小;在酪蛋白、茶多酚、乳糖添加量分别为0.2%、0.06%、0.1%时乳状液ζ-电位绝对值最小;在单甘脂、卡拉胶、碳酸镁添加量分别为0.15%、0.02%、0.01%时乳状液ζ-电位绝对值最大;在柠檬酸钠添加量为0.02%时,乳状液平均粒径最大,在碳酸镁、脱脂奶粉添加量分别为0.01%、2%时,乳状液平均粒径最小。奶茶体系中不同的共存物影响了乳状液的双电层结构,进而改变了大豆分离蛋白的乳化性。     

豆浆机刀具结构及其力学效应对豆浆品质的影响

以大豆为原料制作豆浆,研究刀具结构及豆浆制作过程中的力学效应对豆浆品质的影响。结果表明：刀具倾角α较大时,其打击力较大,切向力较小,制作豆浆时,豆渣率小,豆渣的粒度、硬度小,从而导致豆浆中更多营养物质混入到豆渣中,使得豆浆中蛋白质、游离氨基酸、总糖、脂肪含量少,黏度大;轴向力较大时,其对物料的搅拌更均匀,温度分布的均匀性较好。根据相关性分析,刀具直径与豆渣硬度呈显著性相关,刀齿轴向角度与固形物含量、黏度、蛋白质含量、总糖含量等也呈显著性相关。     

磷酸化和糖基化对大豆蛋白体外消化性的影响

为探究磷酸化和糖基化对大豆蛋白胃肠道酶解物性质及其肠道细胞跨膜转运的影响.以磷酸化大豆蛋白(添加2％,3％和5％三聚磷酸钠),葡萄糖、葡聚糖分别糖基化的大豆蛋白为研究对象,采用体积排阻色谱法、离子交换层析、Caco-2单层细胞模型等方法分析改性和未改性的大豆蛋白体外消化酶解物的分子质量分布、带电性、疏水性以及肠道细胞转...     

Effects of additional milk replacer feeding on calf health, growth, and selected blood metabolites in calves

The objective of the experiment was to evaluate effects of increased milk replacer feeding on growth, intake, feed efficiency, and health parameters in stressed calves. Holstein bull calves (n = 120; approximately 3 to 8 d of age) were purchased from sale barns and dairy farms and housed in fiberglass hutches. In addition, wood shavings contaminated with coronavirus were mixed with clean shavings and added to each hutch before the start of the experiment. Calves were fed either a fixed amount (454 g/d) of a 20% crude protein (CP), 20% fat milk replacer to weaning at 28 d or a variable amount (454, 681, 908, and 454 g/d on d 0 to 7, 8 to 14, 15 to 31, and 32 to 41, respectively) of a milk replacer containing 28% CP and 17% fat without or with added dietary supplement containing bovine serum. Calves were also fed commercial calf starter and water ad libitum. Plasma IgG concentration in most calves on arrival at the facility was < 10 g/L. Intake, change in body weight, feed efficiency, morbidity and mortality, and selected plasma metabolites were determined. Body weight at 28 d, 56 d, daily body weight gain, intake of milk replacer, fecal scores, days with diarrhea, and days treated with antibiotics were increased with feeding variable amount of milk replacer over the 56-d study. Starter intake from d 1 to 56 was reduced from 919 to 717 g/d in calves fed fixed and variable amounts of milk replacer, respectively. Morbidity, measured as the number of days that calves had diarrhea, was increased by 53% when a variable amount of milk replacer was fed. Calves fed variable milk replacer were treated with antibiotics for 3.1 d compared with 1.9 d for calves fed 454 g of milk replacer/d. Concentrations of plasma glucose, urea N, and insulin-like growth factor-I were increased when calves were fed variable amount of milk replacer. Dietary supplement containing bovine serum had no effect on any parameter measured. There was no effect of milk replacer feeding on concentrations of nonesterified fatty acids, total protein, or growth hormone concentrations. Plasma tumor necrosis factor-α was highest in calves with the highest plasma IgG concentrations on the day of arrival and might be related to the calf's ability to identify pathogens in the environment. Under conditions of this study, calves fed variable amount of milk replacer and exposed to immunological challenge before weaning had greater BW gain, but also increased incidence of diarrhea that required added veterinary treatments.     

植酸及几种酚酸对牛奶蛋白体外消化率的影响

研究植酸和几种酚类物质(阿魏酸、单宁、水杨酸、对- 羟基苯甲酸)在常温和灭菌条件下(121℃,20min)对牛奶蛋白体外消化率的影响。结果表明：植酸和4 种酚类物质均降低蛋白质消化率,降幅为5%～27%;反应后延长静置时间可进一步降低蛋白质消化率;增加胃蛋白酶浓度可使蛋白体外消化率提高1%～9%。     

氨基酸分析仪检测牛乳中掺入的大豆蛋白

利用氨基酸分析仪对牛乳和大豆分离蛋白中的17 种氨基酸进行分离测定,氨基酸浓度在0.025～0.350 μmol/mL时,其峰面积和氨基酸浓度的线性相关系数均不小于0.988,重复性较好,牛乳加标回收率范围在94.2%～103.1%,相对标准偏差在0.89%～3.31%。通过对比分析牛乳和大豆的氨基酸图谱找到含量差异较大的6 种氨基酸,并根据模拟掺假实验样品的氨基酸分析6 种氨基酸含量和掺假量的线性关系,相关系数R2达0.889,建立牛乳中大豆蛋白掺假的定性定量检测方法。