类胡萝卜素与畜禽产品着色

类胡萝卜素作为一种天然着色剂已经被广泛应用于畜牧生产中。作者简要阐述了类胡萝卜素在动物机体内的分布及其着色机理，并对影响类胡萝卡素着色的因素作一概述。     

共轭亚油酸和叶黄素影响肉鸡生长性能和免疫反应

<正>类胡萝卜素和脂肪酸的相互作用十分重要,同时两者又是细胞膜的组成部分。研究表明共轭亚油酸具有免疫调节作用,影响机体的组成并防止脂肪蓄积。叶黄素是自然界中第二丰富的类胡萝卜素和膳食叶黄素。叶黄素是氧化的类胡萝卜素,维生素A的活性缺失或减少。研究表明,叶黄素可提高机体体液和细胞免疫能力,最终以抗氧化的方式提高机体天然免疫能力。Selvaraj和Klasing报道,家禽叶黄     

类胡萝卜素生物学作用的研究进展

自然界存在的具有类胡萝卜素特性的物质约有600多种,其中有些具有维生素A(VA)原活性,在动物体内可转化成VA。有些是禽产品良好的着色剂。有些在低氧分压条件下是动物体内独一无二的抗氧化剂。近年来还发现,类胡萝卜素在增强机体免疫和抑制肿瘤方面起着独特作用。本文仅就这方面的研究作以综述。     

类胡萝卜素与畜禽产品着色的关系

类胡萝卜素作为一天然着色剂已经被广泛应用于畜牧生产中。本文简要阐述了类胡萝卜素在动物机体内的分布、吸收及着色机理，并对影响类胡萝卜素着色的因素做一概述。     

类胡萝卜素与畜禽产品着色

类胡萝卜素作为一种天然着色剂已经被广泛应用于畜牧生产中。本文简要阐述了类胡萝卜在动物机体内的分布及其着色机理，并对影响类胡萝卜着色的因素作一概述。     

类胡萝卜素代谢及功能研究进展

类胡萝卜素是维生素A的前体,不仅是动物体内维生素A的最主要来源,还在预防疾病、提高机体免疫力、维持动物正常生长与繁殖以及着色等方面发挥着重要的作用。随着研究的深入,类胡萝卜素在人类健康及动物生产中的作用日益受到重视,但其吸收、转运及代谢机制尚不完全明确。本文在论述类胡萝卜素的基本特征、吸收和转运的基础上,重点综述了类胡萝卜素的代谢机制以及生物活性功能方面的研究进展,为进一步研究类胡萝卜素的代谢机制、功能以及发掘新功能提供理论依据。     

β-胡萝卜素的生物学作用及其机理

β-胡萝卜素是哺乳动物体组织中含量最丰富的类胡萝卜素,是维生素A的重要前体物。β-胡萝卜素及其代谢产物是组织代谢中的关键调节信号因子,因而在哺乳动物(包括人)机体中发挥了许多有益作用。本文概述了β-胡萝卜素对动物生产性能、免疫功能和繁殖性能等方面的作用及其机理。     

β-胡萝卜素的生物学功能及在动物生产中的应用

β-胡萝卜素(β-carotene)是类胡萝卜素的一种,又称为维生素A原,具有抗氧化、抗炎、防癌抗癌等特性;其常作为维生素A原及抗氧化剂添加在饲料中,广泛的应用于畜牧生产.本文综述了β-胡萝卜素代谢途径、生物学功能及其在动物生产中的应用,以期为其进一步的开发利用提供参考.     

类胡萝卜素的吸收代谢及其功能的研究进展

本文综述了类胡萝卜素在肠道的消化吸收和代谢转运、类胡萝卜素的抗氧化和免疫调节作用及其在基因表达调控中的重要作用、母源类胡萝h素在胚胎发育的作用及类胡萝卜素相关代谢基因在卵巢中的表达.类胡萝卜素的吸收机理以及生理功能的深入研究对人类健康、其在畜牧业中的应用以及功能性食品的生产具有重要作用.     

类胡萝卜素应用的研究进展

类胡萝卜素在自然界中广泛存在。由于其具有抗氧化、抗癌、诱导肿瘤细胞凋亡等生物活性,因此,其与一些疾病的发生发展存在着相关性。本文就类胡萝卜素的结构、性质及合成途径等方面展开讨论,着重介绍类胡萝卜素的生物活性,以及类胡萝卜素与疾病的关系,为进一步研究类胡萝卜素的代谢分子机制、及其在抗癌等领域的应用奠定基础。     

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 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 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 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 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.