Faecal shedding detected earlier than immune responses in goats naturally infected with Mycobacterium avium subsp. paratuberculosis

Paratuberculosis was diagnosed in a goat herd that participated in a sanitation program against Mycobacterium avium subsp. paratuberculosis. The aim of this study was to characterise the development of gamma interferon (IFN-γ) and antibody responses as well as the occurrence of faecal shedding. Faecal culture appeared surprisingly sensitive as about 18% and 40% of the goats were positive at 9 and 15-17 months of age, respectively, and shedding was often seen prior to peripheral immune responses. Peripheral IFN-γ responses were not related to protection as clinical and high shedding goats often had high responses. An IFN-γ response usually preceded a humoral response. However, positive antibody titers could sometimes be seen simultaneously with, and even prior to, IFN-γ responses. In conclusion, faecal culture appeared as sensitive as IFN-γ testing. Furthermore, the antibody ELISA and the IFN-γ assay may perform equally well in an infected herd if surveillance is conducted annually.     

用重组核衣壳蛋白ELISA检测PRRSV抗体的研究

ＰＲＲＳＶ重组Ｎ蛋白ＥＬＩＳＡ检测人工感染猪血清７５份,与ＩＤＥＸＸ公司ＥＬＩＳＡ试剂盒及ＩＦＡ的符合率分别为９７．３％和１００％。检测疫苗免疫猪血清,阳性率１００％。在免疫后６ｄ就能检出抗体,比ＩＦＡ敏感。检测８５份我国田间猪血清,阳性率１８．８％。     

Effect of supplementing graded concentrations of non-phytate phosphorus on performance,egg quality and bone mineral variables in White Leghorn layers

1. An experiment was conducted to determine optimal non-phytate phosphorus (NPP) concentrations for White Leghorn (WL) layers (22–72 weeks) fed diet containing 38 g Ca/kg.

2. Eight diets with graded concentrations (1.5–3.25 g/kg in increments of 0.25 g) of NPP were prepared. Each diet was fed to eight pen replicates containing 88 birds in each. Performance data was evaluated in three different phases (phase I-22–37 weeks, phase II-38–53 weeks and phase III-54–72 weeks). Optimum levels of NPP were determined by fitting a quadratic polynomial (QP) regression model.

3. Egg production (EP) was not affected (P = 0.059) by the concentration of NPP and interaction between NPP and diet phase was non-significant, indicating that the lowest concentration (1.5 g/kg diet) of NPP used in the study was adequate across the three phases. However, EP was influenced by phase (P < 0.001).

4. Optimum concentration of NPP for feed intake (FI) was estimated to be 1.5, 1.71 and 2.40 g/kg diet during phases I, II and III, respectively. FI per egg mass (EM) or feed efficiency (FE) responded quadratically with NPP and also differed significantly between phases. Optimum concentration of NPP for FE during phases I, II and III was 1.5, 2.56 and 2.32 g/kg diet, respectively.

5. Egg weight (EW), EM, shell weight and thickness were not affected by NPP concentration although all of these variables (except shell weight) were influenced by phases.

6. Breaking strength of tibia and Ca contents in tibia ash were not affected by the concentration of NPP, but bone ash and P contents in tibia ash were influenced (P < 0.001) by NPP. Predicted optimal concentrations of NPP for responses for tibia ash at 44 or 72 weeks, tibia ash P at 44 weeks and tibia ash P at 72 weeks were 1.55, 2.63 and 1.5 g/kg diet, respectively.

7. Based on the results, it was concluded that WL layers required 1.5 g, 2.63 g and 2.4 g, respectively/kg diet during phase I, II and III with the calculated daily intake of 137.3, 278.3 and 262 mg NPP/b/d.     

Modelling cumulative egg production in laying hens and parent stocks of broiler chickens using classical growth functions

ABSTRACT

1. The objective of the present study is to introduce fresh insight into modelling of egg production by applying classical growth functions to egg production records reported by Aviagen Management Guide to laying hens and the parent stock of broiler chickens.

2. The functions (monomolecular, logistic, Gompertz, Richards and Morgan) were fitted using nonlinear regression procedures of SAS software, and their performance was assessed using goodness-of-fit statistics (coefficient of determination, residual mean squares, Akaike information criterion and Bayesian information criterion).

3. Overall, except for the logistic and Gompertz, the growth functions evaluated gave an acceptable fit to the cumulative egg production curves, with the Morgan equation ranking first followed by the Richards equation. The Morgan and Richards equations provided satisfactory predictions of weekly egg yield at different egg production stages, from early to late production, whereas the least accurate estimates were obtained with the logistic equation.

4. In conclusion, classical growth functions proved feasible alternatives to fit cumulative egg production curves of laying hens and parent stock of broiler chickens, resulting in suitable statistical performance and accurate estimates of production.     

苯酚在兽医生物制品检测中的应用

作者们发现可以用低浓度苯酚作为破乳剂将油乳剂疫苗中水相分离出来,利用后者在体外进行免疫学测定。应用这个方法发现市售减蛋综合症疫苗中的血凝价为２１０,市售卵黄抗体中新城疫病毒血凝抑制价和抗法氏囊病病毒抗体价分别为２７～２９和２５～２７。     

饲料中添加单宁酸对鹌鹑蛋品质、生产性能及屠宰性能的影响

试验旨在研究日粮中添加不同浓度的单宁酸对鹌鹑蛋品质、生产性能及屠宰性能的影响.选取300只10日龄平均体重(34±4.45)g的健康蛋用鹌鹑,随机分3组,每组3个重复,每个重复33只,按照单因素设计进行饲养试验.对照组饲喂基础日粮,试验组在玉米-豆粕型日粮基础上添加单宁酸(0.10％、0.20％),预试期7 d,正试期...     

Effects of main cereal type and feed form on production performance,egg quality and egg sanitary indices of laying hens

ABSTRACT

1. The experiment was conducted to evaluate the effects of cereal types (maize or wheat) and feed forms (pelleted or mash feed) on production performance, egg quality and egg sanitary indices in laying hens.

2. Three hundred and sixty hens (Jinghong No. 1) at 18 weeks of age were randomly assigned to four treatments with six replicates of 15 hens per replicate according to a 2 × 2 factorial design with two cereal types (maize or wheat) and two feed forms (pelleted or mash feed).

3. Compared with the wheat-based diet, the maize-based diet improved (P < 0.05) average egg weight of laying hens. Yolk colour of hens fed with the maize-based diet was higher (P < 0.05) in comparison to those fed the wheat-based diet, while Haugh units were lower (P < 0.05) for the maize-based treatment. Egg mass and average daily feed intake of hens fed the pelleted diet were higher (P < 0.05) than of those fed the mash diet. However, the mash diet improved (P < 0.05) yolk colour compared with the pelleted diet. The percentage of dirty eggs for the wheat-based diet was higher (P < 0.05) than for the maize-based diet. The percentage of dirty eggs was higher (P < 0.05) in birds fed the pelleted diet compared with those fed the mash diet. There were interactions (P < 0.05) between cereal type and feed form, with regard to average egg weight and shell thickness.

4. In conclusion, dietary cereal type affected average egg weight, yolk colour and Haugh units in eggs, while feed form influenced egg mass, average daily feed intake and yolk colour.     

蛋氨酸螯合锌的制备及其对蛋鹑生产性能的影响

本文介绍了蛋氨酸螯合锌的制备方法及其对蛋鹑生产性能的影响。试验结果表明 :获得蛋氨酸螯合锌的最佳条件为 :反应液蛋氨酸浓度为 6.1 2 % ,p H值为 5。运用自制的蛋氨酸螯合锌饲喂蛋鹑 ,将 66只蛋鹑随机分成 3组 ,每组基础日粮相同 , 、 组为试验组 ,分别添加0 .0 2 %的蛋氨酸螯合锌 +0 .0 2 %硫酸锌 ,0 .0 4 %蛋氨酸螯合锌。 组为对照组 ,添加 0 .0 4 %硫酸锌。试验结果表明 :各试验组与对照组相比 ,总产蛋数、总产蛋重及料蛋比均差异显著 (P<0 .0 5) ,平均蛋重及蛋中概略养分各试验组与对照组相比差异不显著 (P>0 .0 5)。     

锌对几种淋巴类细胞生长和功能影响的研究

本文研究比较了锌和螯合剂ＥＤＴＡ对淋巴类细胞株ＰＤｃ－Ｂ－１、Ｊｕｒｋａｔ、ＢｏＬｃＬ、６Ｃ９和奶牛ＰＢＭＣ增殖及功能的影响。除奶牛ＰＢＭＣ之外，锌对各株细胞的增殖和功能均无促进作用，在浓度为１０￣１００μｍｏｌ／Ｌ时有明显抑制甚至毒性作用。ＥＤＴＡ对各株细胞的增殖只有抑制作用，在同一浓度时对杂交瘤细胞增殖和抗体分泌的抑制作用基本一致，而对ＰＢＭＣ增殖和Ｉｇ分泌程度不同的抑制作用，是因为不同功能的     

产蛋鸡日粮中添加Vc的效果试验

选取海兰商品蛋鸡１０８只,分为对照和试验Ⅰ、Ⅱ３组,每组３６只,分别饲喂添加０、１００、２００ｍｇ／ｋｇＶｃ的蛋鸡日粮。４２天的试验结果：Ⅰ组提高蛋鸡产蛋数６．３６％,饲料转化效率提高６．７％,经济效益增加１７．０２％;Ⅱ组降低蛋鸡产蛋数１．４５％,降低饲料转化效率２．９４％,比对照组少收入６．３％。说明适宜的Ｖｃ添加量能显著提高产蛋鸡的生产性能。