体外法估测常用饲料原料内源代谢葡萄糖值

研究拟用体外法来测定日粮丙酸和乳酸的产生量,与体内法的结果相结合,建立日粮内源代谢葡萄糖(LFAG)值的体外估测方法,并估测几种常用饲料原料的LFAG值。试验通过将原料进行粉碎过筛作为底物,进行体外模拟"胃-小肠消化"后,收集残渣并烘干粉碎,通过体外发酵产气测得丙酸及乳酸含量,并与前期体内法测得的大肠丙酸吸收量和门静脉乳酸净吸收量进行回归分析,得到体外法测定LFAG的线性回归方程,确定生长猪最佳体外发酵时间。并在此条件下体外测定常用饲料原料LFAG含量。结果表明:当发酵时间48 h时,回归方程拟合度最佳,且丙酸产生量线性回归方程为Y1=3.826 8X1-6.832 9,R~2=0.968 3;乳酸产生量回归方程为Y_2=0.134 1X_2+3.445 0,R2=0.992 5,通过该方法估测4种常用饲料原料玉米、豆粕、大豆皮、小麦麸LFAG含量分别为177.55、32.83、76.02 g/kg和14.83 g/kg。     

仿生消化法中消化酶与消化时间对评定生长猪常用植物性饲料磷体外消化率的影响

本试验旨在探讨仿生消化过程中生长猪体内4种小肠消化酶以及胃期和小肠期消化时间对植物性饲料磷体外消化率的影响,为确定仿生消化法评定生长猪常用植物性饲料磷体外消化率时模拟小肠消化液的组成与最佳消化时间提供参考。试验在SDS-Ⅰ型单胃动物仿生消化系统中进行,以玉米、豆粕和麦麸为测试原料,分3个试验进行。试验1,设置5个处理,1个不添加小肠消化酶的处理(对照)和4个添加不同小肠消化酶的处理,分别添加胰蛋白酶、胰蛋白酶+糜蛋白酶、胰蛋白酶+糜蛋白酶+淀粉酶、胰蛋白酶+糜蛋白酶+淀粉酶+脂肪酶,胃期消化时间为1.25 h,小肠期消化时间为4.00 h;试验2,确定小肠消化液主要消化酶组成后,设置5个不同的胃期消化时间的处理,分别为0.50、0.75、1.00、1.25、1.50 h,各处理的对应小肠期消化时间均设置为4.00 h;试验3,确定胃期消化时间后,设置6个不同的小肠期消化时间的处理,分别为1.00、2.00、3.00、4.00、5.00、6.00 h。以上各处理均设3个重复,每个重复5根消化管,分别测定3种饲料原料的磷体外消化率。结果表明:1)胰蛋白酶、淀粉酶和脂肪酶均可显著提高玉米、豆粕和麦麸磷体外消化率(P<0.05),糜蛋白酶可显著提高豆粕和麦麸磷体外消化率(P<0.05),却显著降低了玉米磷体外消化率(P<0.05)。2)胃期消化时间由0.50 h增加到1.00 h,玉米和豆粕磷体外消化率均无显著性变化(P>0.05);1.25 h时玉米和豆粕磷体外消化率显著降低(P<0.05);消化时间由0.50 h增加到1.00 h,麦麸磷体外消化率显著升高(P<0.05),1.25 h时达到稳定。3)小肠期消化时间由1.00 h增加到6.00 h,玉米、豆粕和麦麸磷体外消化率均显著增加(P<0.05),并分别在3.00、4.00、5.00 h达到稳定。分析以上结果得出:1)可采用胰蛋白酶、糜蛋白酶、淀粉酶和脂肪酶模拟小肠液。2)确定胃期消化时间为1.00 h,小肠期消化时间为5.00 h。     

一种体外评估猪的植物性饲料原料中磷的全消化道表观消化率的方法的可行性

本研究的目的为证实一种体外酶催化方法评估用于猪日粮的植物源的饲料原料中磷(Phosphorus,P)的全消化道表观消化率(the Apparent Total Tract Digestibility,ATTD)的可行性。16只单独圈养的阉猪(19.5±2.9 kg)饲喂半合成的日粮,空白组(对照)和处理组(小麦、大麦、玉米、马铃薯蛋白浓缩物、大豆饼和菜籽饼)的试验时长均为14d。磷的ATTD使用寅氏盐作为标记间接测量。测量体外分解磷分3个连续步骤:酸性溶液中预先浸泡,在强酸溶液中胃蛋白酶消化,中性溶液中胰液酶消化。结果显示,上述所列的几种饲料原料的磷在体内的ATTD分别为0.21,0.37,0.48,0.41,0.33和0.39。在体内磷的ATTD与体外分解磷线性相关(体外分解磷=-0.118(P0.10)+1.171(P0.01)×体内磷的ATTD,R~2=0.91)。因此,这种体外方法成功地预测了本研究测试的植物性饲料原料中磷在体内的ATTD。并且,此方法可被推荐为一种廉价的工具用以快速评估植物性饲料原料中磷的ATTD。     

多重线性回归法测定猪内源磷排泄量及饲料磷真消化率的研究

本研究采用多重线性回归法测定生长猪内源磷排泄量及花生粕和豆粕磷的真消化率。选用6头健康大白×长白阉公猪为试验动物,平均体重为(24.8±1.42)kg。采用6×6拉丁方设计,设6个磷水平(0.09%、0.17%、0.26%、0.35%、0.43%、0.53%),以豆粕、葡萄糖、玉米淀粉等为基础,以花生粕为待测植物性饲料,配制半纯合试验日粮,花生粕和豆粕为磷唯一来源。日粮中添加0.35%Cr2O3作为外源指示剂。试验分6个试验期,每期8 d,6d适应期,2 d收粪期。结果表明,在以g/kg DMI为计量单位条件下,生长猪粪磷的排出量与日粮磷的摄入量呈线性关系(P=0.000 1),回归法测得生长猪内源磷的排泄量为0.526 6 g/kg DMI,花生粕磷的真消化率为28.00%,豆粕磷的真消化率为38.87%。分析粪磷来源发现,内源磷排泄量基本不变(P=0.13),而日粮来源粪磷随日粮含量的增加而增加(P=0.000 1),说明多重线性回归法可用于测定猪内源磷排泄量及非常规植物性饲料磷的真消化率;比较真消化率和表观消化率值说明,真消化率比表观消化率具有较好的重复性。     

单胃动物体外评价方法研究

试验通过对仔猪消化道中主要消化参数进行体外模拟,筛选出仔猪饲料评价最佳体外消化参数。采用正交试验法主要对仔猪胃部的温度、pH值、胃蛋白酶浓度及消化时间进行模拟,在胃部消化的基础上采用正交试验法对小肠pH值、小肠酶浓度、消化时间及缓冲液体积进行模拟。综合分析结果表明仔猪体外消化的最佳参数为:胃部温度39℃、pH值1.5、胃蛋白酶浓度220U/ml、消化时间4h,此时干物质及粗蛋白消化率最高。小肠最佳消化参数为pH值6.0、小肠酶浓度45mg/g、消化时间12h、缓冲液体积300ml,此时干物质、粗蛋白的消化率最高。据此建立一套仔猪饲料体外评价体系。     

仿生消化系统模拟鸡饲料消化的适宜水解时间的研究

本试验旨在通过探讨基于仿生消化系统的酶法条件下蛋鸡各模拟消化阶段的适宜水解时间,为鸡饲料酶学生物学效价评定方法中模拟消化过程的设计提供参考.采用单因素完全随机设计,其中胃消化期的水解时间设6个处理,即1、2、3、4、5和6 h,小肠消化期的水解时间设3个处理,即12、15和18 h.每个处理5个重复,每个重复1根消化管.分别测定不同消化时间条件下,饲粮的干物质消化率和酶水解物能值.结果表明,在胃模拟消化期,玉米-豆粕型饲粮和玉米-豆粕-棉籽粕型饲粮经4、5、6 h消化后干物质消化率和酶水解物能值均无显著性差异(P>0.05),且显著地高于1、2、3 h消化的相应值(P<0.05).在小肠模拟消化期,玉米-豆粕型饲粮12、15、18 h的干物质消化率差异不显著(P>0.05),但12 h的酶水解物能值与15、18 h的酶水解物能值存在显著性差异(P<0.05).而玉米-豆粕-棉籽粕型饲粮的干物质消化率与酶水解物能值从12 h到15 h均显著升高(P<0.05),当消化时间从15 h延长至18 h,其干物质消化率与酶水解物能值均无显著性差异(P>0.05).综合上述结果,胃模拟消化期的适宜消化时间以4 h为宜,小肠模拟消化期的适宜消化时间以15 h为宜.     

应用体外短期发酵法评定牧草及秸秆干物质的消化率

用体外短期发酵法测定了6种牧草和6种秸秆的消化率。试验结果表明,用稀释瘤胃液(50mL)培养6种牧草和6种秸秆适宜的样量为0.5g,适宜的培养时间为36h。在此条件下测得的消化率与Tilley法测定的消化率极显著的正相关(P<0.01),而且该法有较好的重复性。     

猪仿生消化中小肠阶段消化酶对饲粮总能与粗蛋白质消化率的贡献

本试验旨在探讨猪仿生消化中小肠阶段主要消化酶的组成及活性对饲粮养分消化率的贡献,为仿生消化法评定猪饲粮养分的消化率提供参考。试验采用单因素完全随机设计,5个处理分别为胃模拟消化、胃+小肠(淀粉酶)模拟消化、胃+小肠(淀粉酶+糜蛋白酶)模拟消化、胃+小肠(淀粉酶+糜蛋白酶+胰蛋白酶)模拟消化、胃+小肠(淀粉酶+糜蛋白酶+胰蛋白酶+小肠消化4 h时补充消化酶)模拟消化,每个处理5个重复,每个重复1根消化管。考察各处理条件下玉米、豆粕、小麦麸及玉米-豆粕型饲粮的干物质、粗蛋白质及总能消化率的差异和各消化酶的贡献。结果表明:1)模拟小肠液中淀粉酶、糜蛋白酶均可显著提高胃消化后玉米、豆粕、小麦麸及玉米-豆粕型饲粮的干物质、粗蛋白质以及总能的消化率(P<0.05);胰蛋白酶可以进一步提高胃消化后豆粕、小麦麸的干物质、粗蛋白质以及总能消化率(P<0.05);补充3种消化酶可以提高对小麦麸粗蛋白质及玉米-豆粕型饲粮干物质、粗蛋白质及总能的消化率(P<0.05)。2)小肠液中消化酶对饲粮养分消化率的贡献上,因饲粮底物的不同而异,其中淀粉酶、糜蛋白酶对总能和粗蛋白质消化率的贡献相对较高,而胰蛋白酶和补充消化酶对饲粮养分消化率的贡献虽然相对较少,但也可以引起消化率显著性差异(P<0.05)。在猪的小肠模拟消化阶段,淀粉酶、糜蛋白酶、胰蛋白酶及补充消化酶对饲粮养分的消化程度均有显著性贡献。     

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.     

肉仔鸡体外消化模型的建立及应用效果的研究

<正>众多的体外消化模拟技术各具特色也各有不同程度的不足。尤其是在体外消化参数的确定方法、己消化养分的分离及对影响体外养分消化率的因素考虑全面性等方面,尚存在许多的问题需要解决。有关鸡体外消化模拟技术的研究报道相对较少,大多直接采用猪体外消化操作程序来评定鸡饲料或日粮的营养价值。由于不同动物品种之间各项消化参数差异较大,因此,简单地套用猪体外消化模拟方法来预测和评定鸡日粮体内养分消化率与营养价值,     

Heartworm in dogs in Canada in 1983

In late December 1983, 2 800 veterinarians across Canada were sent a questionnaire in order to assess the status of heartworm disease in Canada in 1983 and 26% of them responded. Veterinarians reported that 59 504 dogs were blood-tested to check for microfilariae and 771 dogs (1.30% of those tested) were found with Dirofilaria immitis. Heartworm disease was diagnosed in all provinces except New Brunswick and Newfoundland but most (733) of the cases were in Ontario.

Heartworm disease was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 31% of the cases were observed with clinical signs of heartworm disease and 64% had a history of not having left Canada. Southwestern Ontario continues to be the focus of the infection and most of the dogs there had not left the province previously.

     

Heartworm in dogs in Canada in 1985

In late December 1985, 1485 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1985 and 44% of them responded. Veterinarians reported that 137,300 dogs were blood-tested to check for microfilariae and 1210 dogs were found with heartworm. Another 36 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number diagnosed in 1985 as 1247 (0.91%).

Heartworm was reported from all provinces except Prince Edward Island, Newfoundland and Saskatchewan but most (1126) of the cases were in Ontario. Southwestern Ontario continued to be the primary focus of the infection in Canada. From Quebec, 91 cases were reported mostly from and around Montreal. From Manitoba, 19 cases were reported from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 28% of the cases were observed with clinical signs of heartworm disease and 78% had a history of not having left Canada.

     

Heartworm in dogs in Canada in 1988

In late November 1988, 1581 small and mixed animal clinics and institutional veterinarians across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1988, and 46% of them responded. Veterinarians reported that 181,577 dogs were blood-tested for heartworm disease and 367 dogs were found with D. immitis microfilariae. Another 60 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1988 as 441 (0.24%).     

Heartworm in dogs in Canada in 1984

In late December 1984, 1853 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1984 and 35% of them responded. Veterinarians reported that 97,794 dogs were blood-tested to check for microfilariae and 1417 dogs (1.45% of those tested) were found with heartworm. Another 34 dogs were amicrofilaremic, but were diagnosed as having heartworm disease, to give the total number diagnosed in 1984 as 1451 (1.48%). Heartworm was reported from all provinces except Prince Edward Island and Newfoundland but most (1310) of the cases were in Ontario. In Quebec, 126 cases were reported mostly from west of Montreal.

Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 27% of the cases were observed with clinical signs of heartworm disease and 72% had a history of not having left Canada. Southwestern Ontario continued to be the primary focus of the infection.

     

Heartworm in dogs in Canada in 1991

In late November 1991, 1883 clinics in Canada were sent a questionnaire to assess the status of Dirofilaria immitis in dogs in 1991 and there was a 60.0% response. There were 344,031 dogs tested for heart-worm (HW), 627 were found infected and the prevalence of HW infection was 0.18%. There were 417 dogs with HW in Ontario, 116 in Manitoba, 38 in Quebec, 53 in British Columbia, three in Alberta, and one in Nova Scotia. In British Columbia, all of the infected dogs but one were from the Okanagan valley which, as from 1991, is a new focus of infection in Canada. Most dogs with HW had not been on preventive medication in 1990, and the prevalence among dogs tested and unprotected was 0.59%. That prevalence was considerably higher in endemic areas. Companion dogs, over three years of age and maintained primarily outdoors in rural areas, were most frequently infected. One cat was diagnosed with D. immitis and 33 dogs had Dipetalonema reconditium.     

Heartworm in dogs in Canada in 1989

In late November 1989, 1732 clinics and institutional veterinarians were sent a questionnaire to assess the status of Dirofilaria immitis, and 51.7% responded. Of 247,716 dogs tested, 394 had D. immitis microfilariae and 51 were amicrofilaremic for a total of 445 cases and heartworm prevalence of 0.17%. Most (408) of these dogs had no preventive medication and the prevalence among dogs tested and unprotected was 1.01%. That prevalence was considerably higher in endemic areas. Thirty-seven dogs with heartworm had preventive medication. Heartworm was most frequent in companion dogs over three years of age maintained outdoors in rural areas. About 75% of the cases had never left Canada, 26% had clinical signs and 125 were not treated.

Heartworm was reported from British Columbia, Manitoba, Ontario, Quebec, Nova Scotia and Newfoundland, but 383 cases were in Ontario. South-western Ontario was the primary focus of infection. There were 33 cases in Quebec and 24 in Manitoba, mainly found in and around Metropolitan Montreal and Winnipeg respectively.

     

Heartworm in dogs in Canada in 1987

In late November 1987, 1246 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1987, and 50% of them responded. Veterinarians reported that 165,428 dogs were blood tested for heartworm disease and 511 dogs were found with D. immitis microfilariae. Another 78 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1987 as 589 (0.35%).     

Heartworm in dogs in Canada in 1986

In late December 1986, 1224 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1986; 46% of them responded. Veterinarians reported that 150,989 dogs were blood-tested for microfilariae and 869 dogs were found with heartworm. Another 65 dogs were amicrofilaremic but diagnosed with heartworm disease and one was found with heartworm at necropsy to give the total number diagnosed in 1986 as 935 (0.62%).

Heartworm was reported from Manitoba, New Brunswick, Ontario and Quebec, but most (810) of the cases were from Ontario. South-western Ontario continued to be the primary focus of the infection in Canada. There were 103 cases reported from Quebec, mostly from and around Montreal, and 21 cases from Manitoba, from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 33% of the cases were observed with clinical signs of heartworm disease and 81% had a history of not having left Canada.