饲料中胰蛋白酶抑制剂的抗营养作用

<正>胰蛋白酶抑制剂的抗营养作用普遍存在于饲料中,它不仅能与动物小肠液中的胰蛋白酶结合来降低胰蛋白酶的活性,还会引起动物体内蛋白质内源性消耗。消除饲料中胰蛋白酶抑制剂对动物体的影响是待解决的难题。本文针对胰蛋白酶在饲料中的抗营养作用作一综述。1胰蛋白酶抑制剂的分布及分类胰蛋白酶抑制剂,又被称作抗胰蛋白酶因子,分子式为C284H432N84O79S7。是一种具有生理活性功能的小分子量的蛋白     

大豆胰蛋白酶抑制因子（TIs）及其钝化

大豆胰蛋白酶抑制因子（ＴＩｓ）及其钝化河南洛阳市农牧局王向阳南京农业大学动科系吴迪，陆治年大豆饼粕是畜禽最重要的蛋白质饲料资源，但是其营养价值受许多抗营养因子的影响。例如：胰蛋白酶抑制因子（ＴｒｙｐｓｉｎＩｎｈｉｂｉｔｏｒｓ——简ＴＩｓ）、低聚糖、植...     

饲草饲料中的抗营养因子及其对畜禽的影响

抗营养因子(anti-nutririon faetor,ANF)是指某些牧草和饲料作物在正常生长代谢过程中所产生,并通过不同机制对畜禽营养过程产生负效应的一类物质。一般来讲,它可引起畜禽生长减慢、饲料转化率降低、体内激素水平改变和器官损伤等,严重者可导致死亡。1.降低畜禽对饲料蛋白质消化利用1.1 蛋白酶抑制剂蛋白酶抑制剂广泛存在于植物界,特别是豆科植物,并以果实中居多(大豆叶子中含量也很高)。已经证实,蛋白酶抑制剂分为二种:即胰蛋白酶抑制剂和胰凝乳蛋白酶抑制剂。     

大豆中抗营养因子及其处理方法

大豆是一种优良的植物蛋白资源,其中含有35％的粗蛋白,经过加工而成的大豆饼粕含有42％左右的粗蛋白,而且必需氨基酸丰富平衡,因此是动物日粮中最常用的蛋白质饲料。但是其中也含有多种抗营养因子（ Antinutritional factors, ANFs）,加工或饲用不当,不仅会造成营养价值下降,而且危害动物健康,影响畜禽生产性能（表1）。1大豆及大豆饼粕中的抗营养因子表1大豆抗营养因子的含量及对动物的危害1.1蛋白酶抑制剂（Protease inhibitors, PI） 　　在自然界中已发现数百种蛋白酶抑制剂,大豆中普遍存在的为胰蛋白酶抑制剂（ Trypsin…     

挤压膨化对全脂大豆中的胰蛋白酶抑制因子和凝集素的影响

长期或短期喂给畜禽生大豆产生不利影响，归于大豆中的主要抗营养因子蛋白酶抑制因子和凝集素所致（Ｌｉｅｎｅｒ，１９８９）。蛋白酶抑制因子包括Ｋｕｎｉｔｚ胰蛋白酶抑制因子和ＢｏｗｍａｎＢｉｒｋ糜蛋白酶抑制因子，前者仅抑制胰蛋白酶的活性，后者既抑制胰蛋白酶又...     

改善大豆饼(粕)品质的途径

大豆饼（粕）含有丰富的蛋白质和优质的氨基酸，其粗蛋白质含量为42％-47％，赖氨酸含量超过2％，除含硫氨基酸稍欠缺外，其它必需氨基酸含量丰富，比例平衡，因此成为畜禽养殖业中重要的蛋白质饲料。生大豆饼（粕）中含有抗营养因子，需予以去除，否则利用效果大为降低。1大豆饼（粕）的抗营养因子及其不良作用生大豆饼（粕）中有多种抗营养因子，分别为胰蛋白酶抑制因子（TrypsinInhibitors，简称TI）、血球凝集素、脲酶、抗维生素因子、促甲状腺肿素、雌激素、皂角素、低聚糖类等。其中TI对畜禽危害最大，因而对它的研究最多。脲酶能…     

饲料抗营养因子机理研究

为满足现代畜牧业蓬勃发展的需要，饲料原料在不断拓宽。但其中许多植物性资源在生长、加工、贮存过程中常产生一些降低饲料营养价值的物质──抗营养因子，使饲料的利用率下降，且影响畜禽的生长性能和产品品质。当前人们已发现有数百种抗营养因子，并研究出一些消除方法，但对抗营养因子对动物的作用机理还研究得不够深入。本文就目前研究的一些结果作一介绍，供深入研究参考。l饲料抗营养因子1.1蛋白酶抑制因子蛋白酶抑制因子（ProteaseInhibitors）因主要抑制蛋白酶活性而得名。蛋白酶抑制因子存在广泛，对它的研究也最多，该抑制因子…     

豆粕制品质量的评定方法

大豆粕是我国以及世界畜牧业生产中主要的植物蛋白质饲料来源，其用量占粕饲料的７０％。大豆饼（粕）蛋白质含量高，一般在４４％左右，赖氨酸含量高于其他粕，其应用价值均优于其他粕。但是，生大豆粕中含有多种抗营养因子，尤其是抗胰蛋白酶抑制因子（ＴＩ），它的活性高低直接关系到单胃动物对大豆粕蛋白质的消化吸收与利用。当猪、禽饲喂生豆粕后，则会引起拉稀，从而影响增重和产蛋率；对于犊牛、仔猪则会引起严重腹泻，增重缓慢，甚至死亡。通过对大豆粕的研究发现，大豆粕中的抗胰蛋白酶抑制因子（ＴＩ）含量与其中的豚酶（ＵＡ）含…     

常见兔饲料中的有毒成分

１胰蛋白酶抑制因子这类物质在生化结构上是由氨基酸残基组成的多肽，它们在胃内不被破坏，进入小肠后与胰蛋白酶结合形成复合物，使胰蛋白酶失去活性。这种复合物在小肠中不会被分解，进入大肠后可被微生物降解，或者经粪便排出体外。因此，胰蛋白酶抑制因子不仅阻碍蛋白质消化，而且会使兔体丧失部分蛋白质（胰蛋白酶本身是一种必需氨基酸含量较高的兔体蛋白）。在家兔的常用饲料中，大豆的胰蛋白酶抑制因子含量特别高（可达１０．７μg／g）。因此，家兔长时间饲喂生大豆可发生胰腺代偿性肿大和蛋白质消化不良现象，以生长兔最为明显，成…     

大豆胰蛋白酶抑制因子及不同加工处理大豆在家兔饲养中的应用研究进展

我国是世界上主要大豆生产国之一 ,大豆及其不同加工处理产品是我国畜禽日粮中主要的植物性蛋白质饲料来源 ,所以对其所含抗营养因子的研究具有重要意义。到目前为止 ,国内外有关大豆中胰蛋白酶抑制因子的研究逐渐深入 ,从对畜禽 (主要是猪、鸡 )和实验动物 (大鼠、小鼠和豚鼠 )生产性能、胰腺重量的影响 ,到对营养物质消化、消化道消化酶活性、胰腺胰液分泌的影响及对某些种类畜禽的危害机理已比较清楚。1　大豆及其所含胰蛋白酶抑制因子1 1　大豆及其营养学特性　大豆为双子叶植物纲豆科大豆属一年生草本植物。大豆中约含35 %粗蛋白质、1…     

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 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.