Correlation analysis of the total IgY level in hen serum,egg yolk and offspring serum

The correlation between IgY levels of the serum and the yolk has been well documented in wild and domestic birds. The levels of total yolk IgY can be an index of the general health status of birds and may contribute to breeding programs when fitness of the offspring is a concern. We measured the levels of total serum IgY and yolk IgY in three different breeds (White Leghorn, Silkie and Dongxiang blue-shell) using indirect ELISA, and found that there was a significantly positive correlation between the levels of total serum IgY and total yolk IgY in all three breeds (White Leghorn: r = 0.404, P < 0.001, n = 100; Silkie: r = 0.561, P < 0.001, n = 70; Dongxiang blue-shell: r = 0.619, P < 0.001, n = 30). We also measured the total serum IgY levels in the 3-day-old offspring hatched from the Silkie hens and results were significantly correlated for serum IgY levels (r = 0.535, P < 0.001, n = 70) and the yolk IgY levels (r = 0.481, P < 0.001, n = 70). The regression analysis showed simple linear regression between IgY levels in hen serum, yolk and offspring serum. Our results suggest that total IgY level could be used as an index for chicken fitness.     

Correlation analysis of the total IgY level in hen serum,egg yolk and offspring serum

The correlation between IgY levels of the serum and the yolk has been well documented in wild and domestic birds. The levels of total yolk IgY can be an index of the general health status of birds and may contribute to breeding programs when fitness of the offspring is a concern. We measured the levels of total serum IgY and yolk IgY in three different breeds （White Leghorn, Silkie and Dongxiang blue-shell） using indirect ELISA, and found that there was a significantly positive correlation between the levels of total serum IgY and total yolk IgY in all three breeds （White Leghorn： r = 0.404, P 〈 0.001, n = 100; Silkie： r = 0.561, P 〈 0.001, n = 70; Dongxiang blue-shell： r = 0.619, P 〈 0.001, n = 30）. We also measured the total serum IgY levels in the 3-day-old offspring hatched from the Silkie hens and results were significantly correlated for serum IgY levels （r = 0.535, P 〈 0.001, n = 70） and the yolk IgY levels （r = 0.481, P 〈 0.001, n = 70）. The regression analysis showed simple linear regression between IgY levels in hen serum, yolk and offspring serum. Our results suggest that total IgY level could be used as an index for chicken fitness.     

Growth of Salmonella typhimurium and Salmonella enteritidis in egg yolks from highly immunized hens.

This experiment was conducted to ascertain whether the growth of Salmonella Enteritidis (SE) or Salmonella Typhimurium (ST) would be suppressed in the presence of antibodies contained in egg yolks. Specific pathogen-free chickens (102 days of age) were subcutaneously immunized with oil-adjuvanted bacterin of SE or ST, twice within a four-week interval. During 160 to 170 days of age, eggs were collected, the yolks were removed and mixed with an equal volume of physiological buffered saline, inoculated with ten colony forming units (CFU) of SE or ST, and incubated at 37 degrees C or 20 degrees C for 23 hr. The growth of organisms in each yolk solution was examined. The egg yolk derived from non-immunized hens was examined in the same manner as the controls. There was no difference in the growth titer between the antibody-positive yolk and the negative yolk. The result suggests that the antibodies in the yolk do not influence the growth of each organism, even if the hens are highly immunized.     

Effects of nonimmunized egg yolk powder-supplemented feed on Salmonella enteritidis prevention and elimination in broilers

Chicken consumption is a newly identified risk factor in Salmonella enterica serovar Enteritidis (SE) infection in humans. SE is widely distributed in commercial chicken flocks and high levels of cecal carriage and shedding may lead to broiler meat contamination. In the present study, the preventive and eliminative effect of nonimmunized freeze-dried egg yolk powder (EYP) on SE in broilers was investigated. In the prevention trial, reduced SE counts were observed in liver (P < or = 0.05), cecal contents, and fecal shedding (P < or = 0.05) in birds fed 10% or 5% EYP. Histological examination of cecal wall and cecal tonsils at 23 days postinfection indicated a lesser degree of intestinal pathology. In the elimination trial, a significantly lower (P < or = 0.05) number of SE reached the liver and spleen, and a reduction in cecal carriage and fecal shedding was observed. The histological changes in the cecal mucosa and cecal tonsils reflected an apparent inflammation and mucosal repair and also suggested that the infection had not completely resolved, confirming SE bacterial isolations in the cecal tissue. The present study indicates that supplementing the diets of broilers with 5% nonimmunized EYP, at the early stages of the growing period, reduces preharvest Salmonella load with a minimal degree of intestinal pathology.     

鸭卵黄免疫球蛋白IgY研究进展

鸭卵黄抗体IgY作为一种特异性多克隆抗体，被称为新生代抗体。它有完整型的和缺失型的两种类型的IgY，其缺失型IgY（△Fc）可以有效的排除假阳性反应，能够与别的特异性抗原有效结合而不会发生交叉反应。两种类型的IgY仅在一定的盐浓度环境中产生沉淀反应，目前己建立起多种鸭IgY分离纯化方法。卵黄抗体IgY具有类似于哺乳类IgG、IgE的功能，但鸭I既具有IgG的生物活性，又具有许多比哺乳类IgG更为优越的特点。     

Effect of dietary karaya saponin on serum and egg yolk cholesterol in laying hens

1. The objective of the study was to investigate the effect of dietary karaya saponin on cholesterol deposition in laying hens. 2. A total of 40 Boris Brown hens were randomly assigned at 20 weeks of age to 4 treatment groups and fed on diets supplemented with 0 (control), 25, 50 or 75 mg/kg karaya saponin for an 8-week experimental period. 3. After 8 weeks of dietary supplementation, karaya-saponin-treated groups had significantly lower serum cholesterol (23·0%) and triglycerides but increased high density lipoproteins cholesterol concentration than controls, irrespective of karaya saponin content in the diet. Egg yolk cholesterol and triglycerides were also significantly reduced by dietary karaya saponin. Hepatic cholesterol and triglycerides were significantly reduced by karaya saponin but bile acids concentration in the faeces and liver were significantly increased by karaya saponin. The concentrations of oleic, linoleic and linolenic acids in the yolk were greater in hens receiving karaya saponin than in controls. Karaya saponin significantly increased egg production, feed efficiency and yolk colour compared with controls. Karaya saponin tended to increase egg weight, feed consumption, Haugh units, albumen weight and yolk index. 4. In conclusion, karaya saponin is a potential agent for reducing yolk cholesterol concentration together with an overall increase of production performance and improvement in egg quality.     

Salmonella enteritidis and other Salmonella in laying hens and eggs from flocks with Salmonella in their environment.

Seven Canadian layer flocks with Salmonella enteritidis in their environment were investigated to determine the numbers of hens infected with S. enteritidis, the localization of S. enteritidis in organs of infected hens and the numbers of S. enteritidis-infected eggs produced by two affected flocks. By a microagglutination test (MAT) using S. pullorum antigens, these flocks had more seropositive hens (mean 51.9 +/- 16.9%) than two Salmonella-free flocks (mean 13.0 +/- 4.2%). Culture of tissues of 580 hens (433 seropositive) from the seven flocks detected 26 (4.5%) S. enteritidis-infected hens from two flocks. In one flock, 2/150 hens were infected with S. enteritidis phage type (PT) 8, which was confined to the ceca, and no Salmonella spp. were isolated from 2520 eggs (one day's lay). In the second flock, where 24/150 hens were infected with S. enteritidis PT13, extraintestinal infection was found in nine hens and involved the ovaries and/or oviduct in two hens. Salmonella enteritidis PT13 was isolated from one sample of egg contents and from one sample of cracked shells from among 14,040 eggs (one day's lay) from this flock. The overall prevalence of S. enteritidis-contaminated eggs from the two flocks with infected hens was less than 0.06%. Other Salmonella spp. isolated were S. heidelberg from 58 hens (10%), and S. hadar, S. mbandaka and S. typhimurium from one hen (0.2%) each. The MAT with antigens of S. pullorum had a sensitivity of 81% and a specificity of 24% for detecting S. enteritidis-infected hens.(ABSTRACT TRUNCATED AT 250 WORDS)     

Secretion of Salmonella-specific antibodies in the oviducts of hens experimentally infected with Salmonella enteritidis

The production and secretion of Salmonella enteritidis whole cell antigen-specific antibodies in the oviducts and in the serum of laying hens experimentally infected with Salmonella enteritidis, was analyzed by ELISA. The dynamics of the antibody levels in the oviducts were identical to that in the serum. Subclasses of antibodies (IgA, IgG, and IgM) in the infected hens were found to increase significantly (p < 0.01) compared to those in the control uninfected hens throughout the experiment. IgG and IgM levels in both oviducts and in sera reached to a peak by 14 days post-inoculation, and remained elevated throughout. The secretion of IgA seemed to be transient since the IgA levels increased to a peak 7 days after both primary and secondary inoculations, and declined rapidly. The elevated levels of antibodies were followed by partial clearance of Salmonella organisms from the oviducts. The present results indicate a significant local immune reaction against the Salmonella infection and suggest an association of the local antibodies with the clearance of Salmonella from the oviducts at least partially.     

Colonization of reproductive organs and internal contamination of eggs after experimental infection of laying hens with Salmonella heidelberg and Salmonella enteritidis

Internal contamination of eggs laid by hens infected with Salmonella enteritidis has been a prominent international public health issue since the mid-1980s. Considerable resources have been committed to detecting and controlling S. enteritidis infections in commercial laying flocks. Recently, the Centers for Disease Control and Prevention also reported a significant association between eggs or egg-containing foods and S. heidelberg infections in humans. The present study sought to determine whether several S. heidelberg isolates obtained from egg-associated human disease outbreaks were able to colonize reproductive tissues and be deposited inside eggs laid by experimentally infected hens in a manner similar to the previously documented behavior of S. enteritidis. In two trials, groups of laying hens were orally inoculated with large doses of four S. heidelberg strains and an S. enteritidis strain that consistently caused egg contamination in previous studies. All five Salmonella strains (of both serotypes) colonized the intestinal tracts and invaded the livers, spleens, ovaries, and oviducts of inoculated hens, with no significant differences observed between the strains for any of these parameters. All four S. heidelberg strains were recovered from the interior liquid contents of eggs laid by infected hens, although at lower frequencies (between 1.1% and 4.5%) than the S. enteritidis strain (7.0%).     

Effects of inulin on performance, egg quality, gut microflora and serum and yolk cholesterol in laying hens

1. The present study was conducted to investigate the effects of inulin on laying hens. A total of 360 Brown Nick laying hens were divided randomly into 6 groups of 60 with 6 replicates of 10 hens and fed on diets containing 0 (control), 0·1, 0·5, 1·0, 1·5 or 2·0% inulin during the 4-week trial. 2. Dietary supplementation of inulin reduced cholesterol concentration (mg/g yolk) and content (mg/egg) in eggs. Cholesterol content in eggs decreased linearly with increasing levels of dietary inulin level. 3. Supplementation of inulin in diets decreased coliform bacteria counts and pH in the caecum. The lowest coliform bacteria counts (6·30 ± 0·03 log10 cfu/g) and pH (6·47 ± 0·01) were obtained in the 2·0% inulin group, the two indices decreasing by 21·6% and 3·0% respectively, compared with the control group. Coliform bacteria count and pH were changed linearly in accordance with increasing levels of dietary inulin level. Caecal Bifidobacteria counts were increased in the 2·0%-inulin group. 4. Inulin supplementation of layer diets did not appear to have any adverse effects on laying rate, egg weight, feed intake, feed conversion efficiency, cracked-egg rate, eggshell thickness or Haugh unit compared with the control laying hens. 5. Therefore, dietary supplementation with inulin may lead to the development of low-cholesterol chicken eggs as demanded by health-conscious consumers.     

Deposition of phage type 4 and 13a Salmonella enteritidis strains in the yolk and albumen of eggs laid by experimentally infected hens

Because egg yolk and albumen differ substantially in their abilities to support bacterial growth, the initial level and location of Salmonella enteritidis deposition are critical for determining whether proposed standards for refrigerating eggs are likely to protect public health by preventing extensive microbial multiplication. In the present study, three groups of laying hens were infected with oral doses of approximately 10(9) cells of different S. enteritidis strains (two were phage type 4 and one was phage type 13a) in two replicate trials. For all three S. enteritidis strains, the incidence of yolk contamination (approximately 2.5% overall) was significantly greater than the incidence of albumen contamination (approximately 0.5% overall). The phage type 13a strain was less often isolated from fecal samples at 2 wk post-inoculation than were the phage type 4 strains, but no significant differences between strains were observed in the incidence of egg contamination. Most freshly laid contaminated eggs contained fewer than 1 S. enteritidis cell/ml of egg yolk or albumen, and no sample contained more than 67 S. enteritidis cells/ml.     

鸡蛋中胆固醇含量调控原理与措施

随着人口的老龄化,心血管疾病逐渐成为威胁人类健康的重要杀手。临床和流行病学研究发现,动脉粥样硬化是导致心血管疾病的重要因素。而高脂、高胆固醇膳食与动脉粥样硬化有着密切关系。膳食胆固醇(CH OL)来源于动物性食物,鸡蛋是动物性食品中CH OL含量较高的一种,平均213m g/枚[1]。鸡蛋中的CH OL具有升高血浆总CH OL、LDL-CH OL水平的潜在作用。由于担心其CH OL会引起动脉粥样硬化,人们减少了鸡蛋食用。美国人年均消费鸡蛋从1965年的402枚降至1991年的233枚,全美的鸡蛋消费量下降了16%~25%[1]。因此,从改善人们的饮食和健康、提…     

猪流行性腹泻病毒及其卵黄抗体研究进展

猪流行性腹泻病毒是引起仔猪病毒性腹泻甚至死亡的关键诱因,而安全高效的抗猪流行性腹泻病毒卵黄抗体具有降低仔猪腹泻率、死亡率等优点已应用于生猪养殖。本文总结了近年来猪流行性腹泻病毒的致病机理及其卵黄抗体的制备与应用效果的研究进展,为卵黄抗体在防治猪流行性腹泻上的应用提供理论基础和技术指导。     

Characteristics of Salmonella enteritidis contamination in eggs after oral,aerosol, and intravenous inoculation of laying hens

Experimental infection models are useful tools for understanding how Salmonella enteritidis is deposited in eggs and for testing potential strategies to control eggborne transmission of disease to humans. Oral inoculation of laying hens is presumed to provide the closest simulation of naturally occurring infections, but alternatives such as intravenous or aerosol inoculation have sometimes been recommended as options to induce higher incidences of egg contamination. The present study compared the frequency, level, and location of S. enteritidis deposition in egg contents after experimental inoculation by three different routes. In two replicate trials, specific-pathogen-free laying hens were infected with an S. enteritidis culture mixture prepared to optimize invasive behavior. Groups of hens received either an oral dose of 10(9) S. enteritidis, an aerosol dose of 10(9) S. enteritidis, or an intravenous dose of 10(5)-10(7) S. enteritidis. Oral inoculation led to the highest incidence of fecal shedding of S. enteritidis, whereas intravenous inoculation produced the highest specific antibody titers. Eggs laid during the first 21 days postinoculation were cultured to detect and enumerate S. enteritidis in the yolk and albumen. No significant differences were observed among the three inoculation routes in the frequencies of isolation of S. enteritidis from either yolk or albumen. For all three routes of administration, S. enteritidis was recovered more often from yolk (at frequencies ranging from 4% to 7%) than from albumen (0 to 2%). Over 73% of contaminated eggs harbored fewer than 1 colony-forming unit (CFU) of S. enteritidis per milliliter, and only 3% of such eggs contained more than 100 CFUs/ml. Significantly higher levels of S. enteritidis contaminants were associated with intravenous inoculation than with the other routes. No advantage of using aerosol or intravenous administration of S. enteritidis as an alternative to oral inoculation for inducing the production of contaminated eggs was evident in this study.     

Detection of antibody to Salmonella enteritidis and S typhimurium in the yolk of hens' eggs

Enzyme-linked immunosorbent assays (ELISAs) have been developed to detect IgG antibodies to Salmonella enteritidis and S typhimurium in the yolk of hens' eggs. Better discrimination and more consistent results were obtained between eggs from experimentally infected and uninfected hens by using saline-dilution of yolk rather than chloroform extraction. Threshold absorbance values were determined in three salmonella-free flocks, and on the basis of these results ELISA optical density values greater than 0.25 were considered to be positive for antibodies to salmonella. Four flocks with a history of salmonella infection were examined; three contained birds which were seropositive for S enteritidis by ELISA and from which S enteritidis was isolated, and a large proportion of eggs from these birds contained antibody to S enteritidis. Eggs from the fourth flock had no detectable antibody, although serum antibody was detected in some birds. No salmonellae were isolated from the yolks of the eggs from any of the four flocks.