鸭源呼肠孤病毒对雏鸭致病性研究

30只10日龄樱桃谷肉鸭随机平均分为试验组和对照组,试验组静脉接种分离的鸭源呼肠孤病毒(DRV)SDWF株,每只0.2mL(ELD50=10-2.36/0.2mL),对照组每只静脉接种0.2mL生理盐水。于感染后3、6、9、12、15d每组随机抽取3只采血,利用流式细胞术分析外周血CD4+/CD8+比值变化,并测定血清中IL-6及INF-γ含量以及免疫器官指数,同时观察试验组鸭临床症状、剖检变化及病理组织学变化。结果显示,攻毒后3d,试验组雏鸭表现精神沉郁,食欲不振,生长发育缓慢,体质量下降。剖检变化表现为脾脏出血、肿大、坏死,肝脏坏死。病理组织学变化表现为脾脏、法氏囊淋巴细胞流失严重,网状纤维显现;脾脏坏死,形成肉芽肿,血管动脉管壁疏松、增厚。攻毒后3d,外周血CD4+/CD8+比值升高,随后于攻毒后6、9d开始迅速下降,显著低于对照组(P0.05),后期虽有所回升,但是CD4+/CD8+比值仍然低于对照组;血清中IL-6及IFN-γ含量变化规律与外周血CD4+/CD8+比值变化规律相似,在攻毒后9d均显著低于对照组(P0.05);胸腺、法氏囊指数均在攻毒后6d显著低于对照组(P0.05),脾脏指数在整个试验观察期间高于对照组。结果表明,脾脏、法氏囊是雏鸭感染DRV的主要靶器官,免疫器官淋巴细胞流失严重,T细胞数量减少,IL-6、IFN-γ分泌量降低,从而导致机体免疫抑制。     

Crossbreeding effects for body weight and carcase traits in Pekin duck

1. Three sire lines of Pekin duck, three dam lines and 9 crosses between these two groups were tested in replicated tests from 1987 to 1991. Body weight at the age of 7 weeks (n = 5189), carcase percentage, percentage of abdominal fat and thickness of breast muscles were recorded (n = 1432 for carcase traits).

2. The data were analysed by linear models. All models contained the factors test and sex. When analysing only crosses, general and specific combining abilities (GCA and SCA respectively) were included as well as their interactions with the test. Using the complete data set (lines and crosses), direct genetic and heterotic effects were considered.

3. The factors test and sex were significant in both data sets for all traits.

4. For body weight, all genetic factors were significant. The average heterosis was 65 g ± 9 g (2.2%); the highest observed heterosis was 7.7%.

5. For carcase percentage, the heterosis was always negative (up to — 2.1%), whereas in abdominal fat, a desirable negative heterosis was observed only in one cross. No significant heterotic or combining ability effects were observed in the thickness of breast muscles.

6. Significant interactions between at least one genetic factor and test were found in all traits.

7. The relative importance of GCA and SCA, possible sources of confounding estimates of genetic effects, the importance of heterotic effects and genotype × environment interactions are discussed.     

肉鸭养殖高产高效的五项措施

一选良种,增效益 品种优良的肉鸭,其生产性能的遗传潜力较高,在同等饲养管理条件下,生长速度、抗病力、对饲料的利用率等均优于其它品种的肉鸭,这是肉鸭养殖取得高产高效的前提。优良的肉鸭品种主要有北京鸭、樱桃谷鸭、狄高鸭、上海白鸭等。以北京鸭为例,其体形较大,肉嫩味美,育肥性能好,是闻名中外的“北京烤鸭”的制作原料,     

The effects of tannins on nutrient utilisation in the White Pekin duck

1. Two experiments were conducted to determine the effects of tannins on nutrient utilisation in the White Pekin duck. 2. Experiment 1 was a rapid nutrient balance assay to determine the nitrogen (N) retention and metabolisable energy (ME) of maize, low-tannin sorghum (P-954063) (Sorghum bicolor (L). Moench) and high-tannin sorghum (IS-4225) cultivars for ducks. The assay lasted 120 h, with an initial 24 h food-deprivation period, a 48 h excreta collection period for endogenous losses and a 48 h excreta collection period for ingredient losses. The true metabolisable energy (TMEn) content was lower (P<0.05) in the high-tannin sorghum cultivar (13.85 MJ/kg) than the maize (14.94 MJ/kg) and the low-tannin sorghum cultivar (14.39 MJ/kg). True N retention was lower (P<0.05) for the high-tannin sorghum (0.24 g) than for maize (1.33 g) and low-tannin sorghum (1.1 g). 3. In experiment 2, the brush-border membrane vesicles technique was used to determine whether tannic acid caused inhibition of L-threonine transport across duck intestinal brush-border membrane. The brush-border membrane vesicles were mixed with tannic acid solutions (pH 7.4) to give gradient tannic acid concentrations of 0, 0.05, 0.10, 0.25, 0.50, 1.00 and 2.50%. As a fraction of the control (no tannic acid), the maximal inhibition of L-threonine transport (Imax) under the sodium-gradient condition was 77.10% (P<0.05). Under the sodium-free condition, the maximal inhibition of L-threonine transport (Imax) was 45.15% (P<0.05). 4. These results demonstrated that nutrient utilisation in the White Pekin duck was lower from the high-tannin sorghum cultivar than from the low-tannin sorghum cultivar. The results also suggested that the antinutritive effects of tannins in foodstuffs are due partly to their inhibitory action on intestinal brush-border bound amino acid transporter proteins.     

饲养商品肉鸭六个条件

商品肉鸭生长速度快,饲料转化率高,生产周期短,是农家致富的良好养殖项目。养殖肉鸭,必须提供合适的饲养管理条件,包括温度、密度、光照、饲料、饮水。免疫等,任何一个方面的缺失或不足,都可能大幅度降低养殖效益,甚至导致养殖失败。     

高铜在肉鸭日粮中的应用

选用510只1日龄仙湖3号商品肉鸭，随机分为5组(公母各半)，1—5组全价日粮中含铜水平分别为7、150、200、250和300mg／kg。试验结果表明，肝脏、肌肉与日粮中铜水平相关系数分别为0．889、0．772，而屠宰性能与对照组差异不显著。     

Age-related changes in the distribution of lean, fat with skin and bones in duck carcases

The experimental birds were Pekin ducks (352 males and 352 females) reared to the age of 13 weeks. They were fed standard diets ad libitum. Starting from the second week, 21 males and 21 females were slaughtered every 7 d. Their carcases were divided into the following elements: neck, wings, legs, breast and back, which were then dissected into lean, skin with fat and bones. The body weights of one-day-old ducklings were similar (circa 62 g), but at 5 weeks of age the males were heavier than the females, and at 13 weeks of age their body weights were 3537 g and 2994 g, respectively. In 2-week-old ducks 55.77% of lean was located in the legs, 15.91% in the back part, 2.78% in the wings, 12.47% in the neck and only 13.12% in the breast. Considerable changes in the distribution of lean were noted in the ducks aged 7 weeks. Its percentage decreased in the legs (to 29.34%) and increased in the breast and wings (to 36.86% and 10.96%, respectively). Age-related changes in the distribution of skin with fat were smaller. Its percentage increased in the wings, legs and back, and decreased in the neck and breast. Until the age of 7 weeks the percentage of bones was decreasing quickly in the legs and increasing in the neck and breast, compared with their total weight in the carcase.     

商品肉鸭的饲养管理

１肉雏鸭的饲养管理樱桃谷鸭及北京鸭等肉鸭属快大型肉鸭，０～３周龄为雏鸭，肉雏鸭具有水禽的习性和生理特点，也具有雏禽的一些共性，可是与雏鸡相比，又有不同的特点，在管理上可以稍粗放些，但是肉雏鸭生长发育快，出壳重为５２～６０g，４０～５０日龄上市，体重可达３～４kg，体重增长５０多倍，饲料报酬比较高；另外，雏鸭自身调节温度的机能还不完善；胃容积小，采食少，所以在饲养管理上也必须做到科学和认真，给雏鸭创造一个最理想的环境条件，如适宜的温度、湿度、空气、光照、营养，以及清洁安静的环境等，尽量减少应激，使雏…     

肉鸭的健康养殖

近年来,随着科技不断进步,先进的生产技术和生产方式被广泛应用到养殖业发展中,品种的选育、饲料的配方、生物制品和药物的研发都达到了较高的水平,客观上为养殖业的发展提供了条件和保障。由于养鸭业饲养周期短、见效快、效益好,再加上品种、饲料、疫苗药品等方面有保障,养鸭业发展越来越快,规模越来越大,规模养殖场越来越多。     

商品肉鸭的饲养管理

1雏鸭的饲养管理对肉鸭生产来说,雏鸭的饲养管理是一项即重要又细致的工作,必须抓住每一个环节,每一项措施。1.1雏鸭的生理特点1.1.1调节体温的能力差因为雏鸭绒毛稀短,不能抵御低温环境,所以雏鸭自身调节体温的机能较差,应创造合适的环境温度。1.1.2雏鸭的消化器官容积小,机能尚未健全刚出壳的雏鸭消化器官尚未经过饲料的刺激和锻炼,贮存食物的能力有限,消化机能尚未健全,应有一个逐步锻炼的过程。应给予营养丰富而易于消化的饲料,每次上料不宜太多,吃完再加,保证料盘随时有料,让其自由采食。1.1.3雏鸭十分娇嫩,适应新环境的能力较差雏鸭刚…     

山东部分地区肉鸭群鸭圆环病毒血清学调查

为了解鸭圆环病毒(DuCV)在山东地区的流行情况,本研究采用已建立的间接ELISA(iELISA)方法对山东省潍坊和泰安两个地区的17个肉鸭场1 130份血清进行DuCV抗体检测。结果显示,肉鸭场的DuCV抗体个体阳性率为2%～78%,平均为29.91%(338/1130),群体阳性率为100%(17/17)。潍坊地区的抗体阳性率(42.81%)明显高于泰安地区(17.73%),显示DuCV在老养殖区鸭群中污染更加严重。     

Thoracic teratoma in a white Pekin duck (Anas platyrhinchos domesticus)

Teratomas are infrequent tumors in domestic fowl and have been rarely reported in ducks. It appears that the only case of mediastinal teratoma in a Pekin duck was observed by Alezais and Cotte in 1908. A lobulated, firm mass occupied the thorax of a 7-mo-old male white Pekin duck (Anas platyrhinchos domesticus). The tumor was composed of squamous epithelium, feather follicles, glandular epithelium, bone and cartilage, and thymus and was classified as tridermic, thoracic teratoma.     

多元回归方程估测北京鸭屠体性状的研究

试验测定了202只6周龄北京鸭公鸭的体重X1、体尺性状(体斜长X2、龙骨长X3、胸宽X4)和屠体性状(胸肉重Y1、腿肉重Y2、皮脂重Y3、腹脂重Y4、瘦肉重Y5和脂肪重Y6)共10项指标,在分析体重、体尺性状与屠体性状的相关关系的基础上,以体重、体尺性状为自变量,屠体性状为依变量,构建了估测北京鸭活体屠体性状的回归方程。结果表明:6周龄北京鸭胸肉重、腿肉重、皮脂重、瘦肉重、脂肪重分别与体重、体尺性状呈极显著正相关(P<0.01),腹脂重与体重呈极显著正相关(P<0.01),与体尺性状呈显著正相关(P<0.05);建立的6个最优多元回归方程,经F检验回归关系均达极显著水平(P<0.01),各回归系数也均达到极显著水平(P<0.01),表明各方程的自变量与依变量之间真实存在着多元回归关系,可为估测北京鸭活体胸肉重、腿肉重、皮脂重、腹脂重、瘦肉重和脂肪重提供理论依据,具有一定的参考使用价值。     

提高肉鸭育雏率的几项措施

为提高肉鸭４周龄的育雏率，应采取以下措施。１选择优良雏鸭 符合本品种特征；脐部不内凹，不外凸，不干瘪；肛门周围洁净、无黄、白、绿色粪便粘着；脐部吸收良好，无血迹、血块；喙、眼、颈、腿、爪无畸型。２适宜的育雏条件２．１温度应注意观察雏鸭的活动规律及精神状态及时调温。其温度范围见表１。２．２湿度 １０日龄前舍内的相对湿度为６０％～６５％，１０日龄以后为５０％～５５％。２．３密度较好的雏群密度范围，见表２。２． ４饮水及洗浴雏鸭出壳 ２４ ｈ即开始饮水。雏鸭应饮用温开水，水中可加入适量的大蒜汁，也可用 ５０…     

肉鸭日粮中添加加酶益生素的饲喂效果试验

选用400只1日龄樱桃谷商品肉鸭,随机分成两组,试验组的日粮中添加0.2%的加酶益生素,以探讨在肉鸭日粮中添加加酶益生素对其生长、死亡率、饲料转化率和经济效益的影响.试验结果表明,加酶益生素能促进肉鸭增重、提高饲料报酬、降低死亡率和提高经济效益.     

Genetic analysis of a duck circovirus detected in commercial Pekin ducks in New York

The genetic organization of the duck circovirus (DuCV) 33753-52 detected in commercial Pekin duck flocks from Long Island, NY, is described. The nucleotide sequence of virus 33753-52 exhibited high similarity with DuCVs previously detected in Germany and Hungary. It is possible that this DuCV from New York shares the same ancestor with the European counterparts. The virus 33753-52 exhibited genetic features characteristic of other circoviruses, such as the presence of two major open reading frames (rep and cap), two intergenic regions, one stem-loop structure, four intergenic direct repeats, and the conserved motifs for the rolling circle replication and for the dNTP binding domain in the Rep protein. This report is the first report of the presence of DuCV in commercial Pekin duck farms in the United States. The clinical and pathologic significance of DuCV in the duck farms located on Long Island needs to be clarified. DuCv was detected in culled birds, due to low body development, leg deformities, or arthritis. Staphylococcus aureus and Riemerella anatipestifer serotype 4 were isolated from some of the DuCV-positive birds. The apparent low prevalence of the virus suggests that at this time, this infection is not a significant problem for the duck industry in New York. However, the immunosuppressive properties of this virus need to be clarified as well as its role as a predisposing agent for other diseases.