日粮核黄素水平对热应激条件下肉仔鸡免疫机能的影响

本试验采用360只21日龄Arbor Acres商品代肉仔鸡,随机分成6组,每组3个重复,每个重复20只鸡,公母各半,试验期为5周,研究日粮核黄素水平对热应激条件下肉仔鸡免疫机能的影响。日粮中添加的核黄素水平分别为0、1.6、5.2、12.4、23和48mg/kg。试验结果表明,高温条件下添加不同水平的核黄素均可以显著降低肉仔鸡的死亡率(P<0.05)。不同添加水平的核黄素对热应激条件下42日龄、56日龄肉仔鸡的胸腺、脾脏、法氏囊相对重量无显著影响(P>0.05)。不同添加水平的核黄素显著提高了热应激条件下42日龄肉仔鸡血清新城疫抗体效价。随着日龄的增长,添加5.2、12.4、23和48mg/kg水平的核黄素可以显著提高肉仔鸡56日龄血清新城疫抗体效价(P<0.05)。由此得出:添加2倍于NRC水平的核黄素可以显著提高热应激条件下肉仔鸡的血清新城疫抗体效价,降低肉仔鸡的死亡率。     

大肠杆菌产植酸酶在肉仔鸡日粮中的应用效率

本试验研究了添加大肠杆菌产植酸酶对提高肉仔鸡生产性能及营养利用率的影响。将144只7日龄雄性肉仔鸡按体重分为6组，每组6个重复。将6种以玉米一豆粕为基础的粉状日粮随机分给每组。6组日粮中分别有磷充足组（7.7g/kg），低磷组（3.9g/kg）。低磷组添加0.75g或1.5g磷酸钠盐和大肠杆菌产植酸酶500或1000单位/kg。在8～22日龄时饲喂试验日粮。结果表明，大肠杆菌产植酸酶提高了体增重（P＜O.05）、采食量（P＜0.01）、胫骨灰含量（P＜0.01）和磷（P＜0.001）、钙（P＜O.01）、氮（P＜0.05）、氨基酸（P＜0.05）的利用率。因此，大肠杆菌产植酸酶有效地提高了肉仔鸡的生产性能及骨骼沉积，并且可有效提高磷、钙、氮、氨基酸的利用率。     

黄石散对肉仔鸡生产性能和肠道茵群韵影Ⅱl荀

试验采用单因子随机设计,选用1日龄AA肉仔鸡180羽,分成4组（空白组、试验l组、试验2组、试验3组）,每组5个重复,分别饲喂添加0％、0．6％、1．2％、2．4％黄石散的基础日粮,试验为期6W,探讨黄石散对肉仔鸡生产性能,肠道茵群的影响。结果表明：与对照组相比,试验1组和2组日均采食量分别提高了5．5．％、7．82％（P〈O．05）,试验1组、2组和3组与对照组相比平均日增重分别提高了7．55％、11．37％和6．06％（P〈O．05）;试验1、2、3组与对照组相比,空肠和盲肠中乳酸杆菌显著提高（P〈O．05）,大肠杆菌显著降低（P〈0．05）。该试验表明饲料中添加黄石散可提高肉仔鸡的生长性能,有益于肠道微生物区系平衡,且肉仔鸡日粮中添加1．2％黄石散效果较理想。     

一种特殊溶菌酶对肉仔鸡生长性能的影响

选取3200羽1日龄艾维菌肉仔鸡随机分为4组，每组4个重复，每重复200羽，比较在相同的营养水平条件下分别饲喂添加溶菌酶、速大肥及恩拉霉素日粮对肉仔鸡生长性能的影响，试验时间42d。结果表明，在试验前期与对照组相比，饲喂添加溶菌酶日粮能提高肉仔鸡的平均日增质量9．37％（P〈0．05），降低料重比11．98％（P〈0．05），差异显著；在试验后期与对照组相比，饲喂添加溶菌酶日粮也能有效提高肉仔鸡的平均日增质量，降低料重比，但差异不显著。与其他抗生素组相比，饲喂添加溶菌酶日粮的肉仔鸡的生长性能也有明显的改善。试验结果表明，肉仔鸡日粮中添加溶菌酶能提高生长性能，同时可替代日粮中的抗生素。     

核黄素对肉仔鸡免疫功能和生产性能的影响

100只1日龄肉仔鸡随机分成4组，每组25只，I－Ⅲ组为试验组，第Ⅳ组为对照组。对照组喂以基础日粮，其他3组分别喂以含核黄素3．6、7．2、14．4mg/kg的日粮，饲喂6周后观察它们对肉仔鸡外周血细胞、免疫器官及生产性能的影响，结果表明：各试验组鸡血浆中白细胞及异嗜细胞数目均高于对照组，其中Ⅱ、Ⅲ组异嗜细胞数与对照组差异显著（P＜0．05）；脾体比试验Ⅱ、Ⅲ组与对照组有显著差异，I组与对照组无差异；各试验组生产性能也均高于对照组。试验结果表明，核黄素可提高机体的抗感染能力及和免疫力，并可提高肉仔鸡生产性能。     

鸡血清免疫球蛋白制剂的应用研究

为研究鸡血清免疫球蛋白制剂对肉仔鸡的应用效果，将360只1日龄艾维茵肉仔鸡，随机分成3组，I组于2日龄肌注血清免疫球蛋白制剂1mL/只，20日龄按1mL/只气雾吸入；Ⅱ组于1－49日龄采食含金霉素（50mg/kg)的日粮；Ⅲ组为对照组，饲粮中不添加任何药物。试验结果表明：I组鸡的死亡率比Ⅲ组降低了49．96％，日增重提高了6．21％（P＜0．05），料肉比降低了5．77％（P＜0．05），并与Ⅱ组无显著差异。28日龄时，HI抗体效价分别比Ⅱ组和Ⅲ组显著增加了9．70％和5．60％（P＜0．05），AGP抗体阳性率分别比Ⅱ组和Ⅲ组提高了25．00％和11．11％（P＞0．05）。提示血清免疫球蛋白制剂具有增强肉仔鸡的免疫功能、减少疾病和促进生长的作用。     

日粮核黄素水平对热应激条件下肉仔鸡生产性能的影响

本试验采用360只21日龄ArborAcres商品代肉仔鸡 ,随机分成6组 ,每组3个重复 ,每个重复20只鸡 ,公母各半。试验期为5周。研究日粮核黄素水平对热应激条件下肉仔鸡生产性能的影响。日粮中添加的核黄素水平分别为0、1.6、5.2、12.4、23、48mg/kg。试验结果表明 ,高温条件下核黄素添加水平对21～42日龄肉仔鸡平均日增重、料重比无显著影响 (P>0.05)。添加12.4及23mg/kg 核黄素组与对照组相比显著增加了43～56日龄肉仔鸡的平均日增重 ,分别增高30.66 %和35.70 % (P<0.05) ,但对料重比无显著影响(P>0.05)。添加不同水平的核黄素可以显著降低肉鸡的死亡率 (P<0.05) ,显著降低热应激条件下生长中期肉鸡的血清肌酸激酶水平 (P<0.05)。随着日龄的增加 ,在试验中期 (4～6周 ) ,添加不同水平的核黄素日粮可以降低肉鸡14:00的呼吸率 ;在试验后期 (6～8周 ) ,添加12.4mg/kg 水平的核黄素日粮可以降低肉鸡9:00的呼吸率。随着环境温度的升高 ,将日粮核黄素水平提高到48mg/kg有降低肉鸡生长后期肛温的作用(P<0.05)。     

牛磺酸对肉仔鸡生产性能和血清生化指标的影响

本研究旨在探讨牛磺酸对肉仔鸡生产性能和血清生化指标的影响。选用288只1日龄AA肉仔鸡,随机分为6组,每组3个重复。第1组为对照组,饲喂基础日粮（不合抗生素）;第Ⅱ组为抗生素组,在基础日粮中添加50mg／kg的杆菌肽锌;第Ⅲ、Ⅳ、Ⅴ、Ⅵ组为牛磺酸添加组,在基础日粮中分别添加0．05％、0．10％、0．15％和0．20％的牛磺酸,试验期42天。结果表明：（1）日粮中添加0．10％牛磺酸,能够显著提高肉仔鸡42日龄平均末重和平均日增重,显著降低料重比（P〈0．05）;（2）添加0．10％的牛磺酸能显著降低42日龄肉仔鸡血清中葡萄糖（GLU）、尿酸（UA）含量（P〈0．05）,显著提高血清总蛋白（TPO）含量（P〈0．05）;0．15％和0．20％的牛磺酸能显著降低血清中GLU含量（P〈0．05）,0．15％牛磺酸使血清高密度脂蛋白胆固醇（HDL—C）含量显著提高（P〈0．05）;添加牛磺酸可以使42日龄肉仔鸡血清甘油三酯（TG）含量有不同程度降低,但差异不显著（P〉0．05）。     

两种铬源对高密度应激下为仔鸡血糖和血清氮化物的影响

本试验研究在高密度应激下日粮中添加吡啶羧酸铬（CrPi）和三氯化铬（CrCl3）对肉仔鸡血糖、血清氮化物的影响。试验选用264只1日龄体重均匀、健康的艾维茵肉仔鸡，随机分成11组，分别喂11种不同饲粮：1组为对照组，喂基础日粮；2-6组为有机铬组，分别在基础日粮基础上添加0.5、1.0、1．5、2．0、2.5mg／kg铬（CrPi）；7～11组为无机铬组，分别在基础日粮基础上添加0．5、1.0、1．5、2.0、2．5mg／kg铬（CrCl3）.在19日龄进行高密度处理。试验表明：①高密度应激显著提高了血糖、尿素氮含量，降低血总蛋白含量（P〈0.05）。而2种铬源均能有效地提高肉仔鸡的抗应激能力。其中添加0．5mg／kg（CrPi）和2mg／kg（CrCl3）组效果较好；②吡啶羧酸铬和三氯化铬作为肉仔鸡饲料微量元素添加剂使用是可行的。     

日粮中添加半胱胺对肉鸡生产性能的影响

选择144只1日龄肉用仔鸡，随机分成4组．每组36只．适应饲养1周后，分别于其基础日粮中添加0、50、100、150mg／kg半胱胺（CS），并于饲喂添加CS日粮后2、4、6、8周屠宰．研究CS对肉仔鸡生长性能的影响。结果表明：（1）在饲料中持续添加CS的前期可影响饲料的适口性。（2）随时间的延长，屠宰率、半净膛率、全净膛率随剂量的加大而升高。（3）在连续添加CS的后期（第6周、第8周）添加50mg／kg的CS组的日增重及料肉比均最好，与对照组相比日增重提高了22．9％、17．8％，料肉比下降了15．7％和3．5％。     

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.