鱼类的核苷酸营养：研究现状及应用展望（续完）

上期回顾：上一期本刊编辑首先提出向畜牧生产推荐此文的目的,随后简要介绍了核苷酸在动物和水产动物营养上的总体研究概况,并提出了有必要对其在水产动物营养上所起作用进行总结和评估的重要性,最后比较详细地介绍了核苷酸的生物化学特征、水产动物对核苷酸及相关代谢产物的消化和吸收和核苷酸对水产动物化学诱食的作用。     

新型水产诱食剂CMDMS的化学合成与应用

水产动物诱食促生长剂，能改变饲料风味、提高摄食速度和摄食量，促进生长，提高饲料利用率，又能水产动物的健康，从而提高生产性能，因此研究，开发新型诱食促生长剂便日益受到广大水产养殖工作者的广泛关注，显示出十分重大的经济效益和社会效益。本文用二甲基硫和溴化乙酸为主要原料合成了一种新型诱食促生长剂－溴化羧甲基二甲基锍（缩写为CMDMS），初步研究了该合成产品对锂鱼的生长影响。     

核苷酸对动物摄食、生长与免疫功能的影响

饲料中的核苷酸对动物生长发育和免疫功能等具有重要作用。核苷酸作为一种无毒无害无残留的新型饲料添加剂,在动物营养方面有很大的发展前途。近年来国内外学者对核苷酸的研究逐渐增多。本文从促生长、诱食和改善免疫功能等方面对核苷酸在动物营养方面的应用做一综述。     

DMPT在水产养殖上的应用

DMPT是一种新型的水产动物诱食促长剂，它广泛存在于水生植物及水产动物体内。DMPT能够促进水产动物的采食并提高水产动物的日增重，但目前对它的研究报道还比较少。本文就DMPT的来源、生理作用及其在水产养殖上的应用做一综述。     

新型水产诱食剂CEDMS的人工合成与应用研究

人工合成了新型水产诱食剂－溴化羧乙 基二甲基锍（缩写为CEDMS）含两个活性甲基，其结构与甜菜碱相似，并研究了它对鲤鱼生长的影响。水产动物诱食促生长剂，既能改变饲料风味，提高摄食速度和摄食量，促进生长，提高饲料利用率，又能改善水产动物的健康，进而提高生产性能，因此研究、开发新型诱食促生长剂便日益受到广大水产养殖工作者的密切关注，显示出巨大的经济效益和社会效益。本文用二甲基硫和β-溴代丙酸为主要原料合成了CEDMS，并初步研究了该合成产品对鲤鱼生长的影响。     

DMPT在水产养殖上的应用

DMPT是一种新型的水产动物诱食促长剂,它广泛存在于水生植物及水产动物体内。DMPT能够促进水产动物的采食并提高水产动物的日增重,但目前对它的研究报道还比较少。     

水产饲料诱食剂的研究现状与展望

由于水产动物生活环境的特殊性，诱食剂在水产动物饲料中的运用显得尤其重要，作者对现阶段水产饲料诱食剂的开发利用现状作了一综述，主要体现在诱食剂的作用机理、功用、诱食剂的种类、诱食剂的研究方法等方面。旨在为开发新的诱食剂和为水产配合饲料科学配制、提高饲料的利用率提供参考依据。     

酿酒酵母营养调控功能及其在水产饲料中的应用研究进展

酿酒酵母细胞壁含有丰富的β-1,3-葡聚糖和甘露寡糖(MOS),可达到细胞壁干重的95%左右,它们在促进水产动物生长、增强非特异性免疫能力方面发挥着非常重要的作用。酵母细胞原生质中含量丰富的核苷酸和氨基酸/小肽能够对水产动物产生强烈的诱食效应,显著促进水产动物生长、提高饲料吸收利用效率,并对水产动物免疫能力具有良好的增强效应。本文综述了酿酒酵母中β-1,3-葡聚糖、MOS、核苷酸和氨基酸/小肽的营养调控功能及其在水产饲料中的应用研究进展,为饲料酵母产品的深入开发利用提供了一定的背景资料。     

诱食剂在水产养殖中的应用

水产动物诱食剂研究不断升温，对诱食剂作用的生理机制进行了分析，概述了目前使用的诱食剂及其诱食效果，简述了诱食剂在渔业生产上利用意义。     

S，S-二甲基-β-溴代丙酸噻亭作为动物诱食剂的研究和应用新进展

近年来．随着高密度集约化养殖业的蓬勃发展．在动物饲料中添加诱食剂以提高饲料产品的利用率是当前饲料生产中面临的主要技术问题之一。动物诱食促生长剂具有多方面的作用与效应。以水产动物诱食剂为例．一方面可以通过自身特殊的气味掩盖饲料中不良气味：另一方面．能加快水产动物的摄食速度．有效降低饲料损耗，提高饲料利用率，减少水体中饲料残饵．减少     

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.