Effect of faecal extract on the growth of Salmonella enteritidis in artificially contaminated hens' eggs.

1. Salmonella enteritidis PT 4 grew in eggs stored at 25 degrees C, but not at 10 degrees C. 2. The incidence of generalised infection of the egg contents (greater than 10(6) salmonellas/ml) was greater in eggs inoculated with cells suspended in faecal extract compared to those with cells in Ringer's solution. 3. The removal of most of the iron did not decrease the growth-promoting effect of the faecal extract.     

Control of Salmonella enteritidis phage type 4 experimental infection by fosfomycin in newly hatched chicks

One hundred and twenty 1-day-old broiler chickens were divided into four groups: group I unmedicated and orally challenged with 1.5×10⁸ cfu of Salmonella enteritidis phage type 4; group F infected and treated with 300 ppm of fosfomycin in their drinking water; group CF uninfected and treated, and group C maintained as a control group. Their performance, clinical signs, S. enteritidis PT4 reisolation and biochemistry variables were compared. Group F showed fewer symptoms and gross lesions than those from group I. Fosfomycin treatment at 300 ppm improved body weight at 7 days of age by 42.3%. S. enteritidis PT4 reisolation in group I was higher than in the treated group, but total decontamination of challenged birds was not achieved. There was an increase in the levels of total protein and globulins in group I but not in the treated group. Fosfomycin caused no adverse effects on chickens from group CF, assessed by performance and biochemical variables. The results indicate that fosfomycin could be used in the treatment of S. enteritidis PT4 experimental infection.     

"聚焦沙门氏菌"专栏四:种蛋的沙门氏菌污染

沙门氏菌污染是种鸡场要面临的一个问题,这是因为如果种蛋及其内容物受到沙门氏菌的污染,种蛋孵出的子代雏鸡、进而引入该雏鸡的鸡场存在受到污染的可能性. 在过去一段时间中,沙门氏菌阳性种鸡群很可能将污染许多子代鸡群或鸡场,而且这种情况不只在一个国家出现. 需要指出的是,如果我们位居育种"金字塔"的顶端,也就是说处于曾祖代种鸡水平,沙门氏菌通过此金字塔向下垂直传播的后果可能会更加显著,因为更多的鸡群最终将受到污染.     

Non-invasive determination of heart rate in newly hatched chicks.

1. Using a flexible piezoelectric probe, we detected non-invasively the cardiogenic precordial movements of domestic fowl chicks and measured heart rate (HR) daily over the first week after hatching (day 0) for comparison with previously measured embryonic HR. 2. HR of the hatchlings was much more variable than embryonic HR. The mean HR at a given age also varied among the 5 chicks measured. 3. The overall mean HR was 280 +/- 20 (SD, n = 5) bpm on day 0. This value was similar to the prepipping HR and lower than that of externally pipped embryos. It increased to 342 +/- 39 bpm 3 days later.     

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)     

Isolation of Salmonella enteritidis from internal organs of experimentally infected hens

Tissues from experimentally infected hens were examined for the presence of Salmonella enteritidis (SE). SE was recovered from internal organs of both orally inoculated hens and hens infected by horizontal contact transmission. SE was isolated from 58% of the ceca, 51% of the livers, 47% of the spleens, 17% of the ovaries, and 17% of the oviducts of hens sampled during the first 5 weeks after exposure. SE was recovered at a low frequency from all internal organs sampled for as long as 22 weeks after exposure.     

Effect of cadmium injected in ovo on hatching results and the activity of plasma hydrolytic enzymes in newly hatched chicks

The aim of the study was to determine the toxicity of cadmium ions in chick embryos, using plasma hydrolytic enzyme as its biomarker. Hatching eggs (n = 300) from Ross 308 broilers were incubated under standard conditions. On day 4 of incubation, 50 μl of saline solution, containing Cd ions at a concentration from 0 (control group) to 24 μg, was injected in ovo into the egg albumen. The results indicate that the administration of cadmium at doses exceeding 1 μg/egg caused a gradual decrease in hatchability, with an LD50 of 3.9 μg/egg. The greatest differences between the groups in the enzymatic activities studied were found for N-acetyl-β-D-glucosaminidase (NAG), β-D-mannosidase (β-MAN) and arylsulphatase (ARYL). Compared to the control group, in the blood serum of chicks from the groups receiving 3, 6 and 12 μg Cd/egg the NAG activity increased by 79, 108 and 54% and β-MAN activity by 33, 119 and 108%, respectively. Exposure to cadmium at a dose of 1 to 6 μg per egg caused an about 60% increase in ARYL activity while a dose of 12 μg decreased the activity by about 35% below the level observed in the control group. These findings show that cadmium has a similar toxicity mechanism in mammals and birds, which opens the possibility of using NAG activity as a biomarker of the cytotoxic effect of cadmium in birds.     

柔嫩艾美耳球虫感染对蛋鸡生产肠炎沙门氏菌污染蛋和感染肠炎沙门氏菌敏感性的影响

为揭示球虫感染对蛋鸡的肠炎沙门氏菌敏感性及鸡蛋的肠炎沙门氏菌污染率的影响而进行了本研究。结果显示,柔嫩艾美耳球虫感染对蛋鸡生产肠炎沙门氏菌污染蛋及感染肠炎沙门氏菌的敏感性均具有增强作用。具体表现为：柔嫩艾美耳球虫感染可使肠炎沙门氏菌污染蛋壳显著增多（Ｐ＜０．０５）;球虫感染鸡所产蛋,无论是新鲜的还是贮存１周后的,其蛋内容物的肠炎沙门氏菌阳性率比仅感染肠炎沙门氏菌鸡所产蛋要高;球虫感染鸡盲肠中的沙门氏菌阳性率和沙门氏菌数显著增加（Ｐ＜０．０１）;球虫感染鸡输卵管中的肠炎沙门氏菌也有增多;球虫感染使泄殖腔拭子的肠炎沙门氏菌阳性率增加。研究结果表明,柔嫩艾美耳球虫感染可以增加鸡群中肠炎沙门氏菌的水平及其垂直传播的危险。     

Effects of probiotics and maternal vaccination on Salmonella enteritidis infection in broiler chicks

The effects of probiotics and maternal vaccination with an inactivated Salmonella Enteritidis (SE) vaccine on day-old chicks challenged with SE were evaluated. A 2 X 3 factorial arrangement was used (with or without probiotics; breeders nonvaccinated, vaccinated intramuscularly, or vaccinated intraperitoneally). Three trials were conducted in isolation cabinets and SE challenge was different between trials. The number of SE organisms per chick and the time interval between housing and introduction of seeder birds (hereafter called challenge) were 1.6 X 10(8) and 1 hr (Trial I), 1.8 X 10(6) and 12 hr (Trial II), and 1.2 X 10(4) and 24 hr (Trial III). SE recovery was assessed in ceca and liver at 3, 5, and 7 days postchallenge, and the number of colony-forming units (CFU) in ceca was evaluated at 5 and 7 days postchallenge. The number of SE (log CFU) in the ceca reduced 0.56 log (from 7.59 to 7.03) and 1.45 log (7.62 to 6.17) because of the treatment with probiotics in Trials II and III, respectively. The greater reduction in Trial III indicates the importance of the early use of probiotics on the prevention of SE infection. Treatment with probiotics resulted in a smaller number of SE-positive livers after 5 days postchallenge on Trial III. Although there was no significant effect of maternal vaccination on the number of SE CFU in the ceca, a significant effect of maternal vaccination on the SE CFU was observed in the liver, but not in the ceca at 5 days after challenge.     

Effects of rearing conditions on the colonization of Salmonella enteritidis in the cecum of chicks.

Salmonella enteritidis is the cause of human salmonellosis associated with contaminated eggs. In this study, we artificially challenged S. enteritidis to chicks just after hatching, and the effects of breeding conditions on the intestinal carriage of S. enteritidis were examined. S. enteritidis was not directly detected from spleen, liver and blood, but were constantly isolated from the cecal contents throughout the experiment. When chicks were reared in the unsanitary conditions and in the high housing density, the numbers of S. enteritidis increased. The subsequent experiment was undertaken to examine whether the antibacterial additive in a feed would have any impact on S. enteritidis colonization in chicks. Some antibiotic effective on the growth promotion had an influence on S. enteritidis colonization.     

Relationship between the weight of hatching eggs and subsequent early performance of broiler chicks

1. The effect of egg weight on the subsequent performance of individual growing chicks was studied. Eggs from commercial broiler breeder hens were collected at 52, 55 and 57 weeks of age and incubated. The chicks were reared for 18 d. 2. Egg weight and hatched chick weight were not affected by the age of the hens during the 52 to 57-week period, but there was a close correlation between egg weight and hatching weight, irrespective of the age of the hens (r = 0.89). Chick:egg weight ratio at hatching was about 0.71 and independent of hen age. One d after hatching, chick weights had decreased by about 1.5 g. 3. The initial high correlation between egg weight and chick weight decreased markedly during post-hatching growth, becoming insignificant 5 d after hatching. At 18 d of age, however, chicks from eggs of older hens tended to be heavier than those from younger birds. The greater 18-d weights appeared to be associated more with higher food intake during that period, than with greater egg weight. 4. It was concluded that, in individual broiler chicks, the advantage of the initially higher weight attributable to a larger egg diminishes rapidly after hatching, and the main factor affecting final body weight is food intake.     

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.     

Effect of species-specific sound stimulation on the development and hatching of broiler chicks

1. Previous research has reported that chicken embryos develop a functionary auditory system during incubation and that prenatal sound may play an important role in embryo development and alter the hatch time. In this study the effects of prenatal auditory stimulation on hatch process, hatch performance, the development of embryo and blood parameters were investigated.

2. Four batches of Ross 308 broiler breeder eggs were incubated either in control or in sound-stimulated groups. The sound-stimulated embryos were exposed to a discontinuous sound of species-specific calls by means of a speaker at 72 dB for 16 h a day: maternal calls from d 10 to d 19 of incubation time and embryo/chick calls from d 19 until hatching. The species-specific sound was excluded from the control group.

3. The onset of hatch was delayed in the sound-stimulated group compared to the controls. This was also supported by comparison of the exact hatching time of individual focal chicks within the two groups. However, the sound-stimulated embryos had a lower hatchability than the control group, mainly due to significantly increased numbers of late deaths.

4. The embryos exhibited a similar growth pattern between the sound-stimulated group and the control group. Although sound exposure decreased body weight at d 16, no consistent effect of sound on body weight at incubation stage was observed. Species-specific sound stimulation also had no impact on chick quality, blood values and plasma corticosterone concentrations during hatch.     

Investigations into possible alternative decontamination methods for Salmonella enteritidis on the surface of table eggs

Investigations into various alternative techniques for decontamination of the surfaces of artificially contaminated shell eggs were carried out. Ionized air, exposure to ozone in a dry atmosphere and use of a commercial herbal antibacterial product were not effective. Application of ozone in a humid environment was only partially effective but a commercial ionized water anolyte was highly effective in eliminating Salmonella from egg surfaces.     

饲料中添加吡喹酮在鸡蛋中的残留及其对孵化率的影响

试验在蛋种鸡饲料中按1:4 000 比例添加吡喹酮,连喂3 d后测定血清和蛋黄中吡喹酮的存留量,停喂后1天收集种蛋进行孵化,以检验吡喹酮对孵化性能的影响.结果表明,吡喹酮在鸡血液中的存留时间较短,但在鸡蛋中还是有积累效应.饲喂吡喹酮期间和以后一段时间内种蛋的受精率和孵化率受到显著影响.     

Effect of used litter from floor pens of adult broilers on Salmonella colonization of broiler chicks.

The effect of used pine-shaving litter from broiler floor pens on Salmonella colonization resistance was evaluated in broiler chicks. One-day-old chicks were placed in floor pens on fresh unused litter or on used litter. All chicks were challenged orally with 10(4) S. typhimurium at 3 days of age. The study was replicated in three trials with used litter that was collected and stored for 1 day (Trial 1), 4 days (Trial 2), or 50 days (Trial 3) before the start of each trial. Cecal concentrations of volatile fatty acids (VFAs) were significantly higher (P < 0.05) in chicks placed on used litter than in chicks on new litter. In all three trials, the number of Salmonella in the cecal contents and the number of Salmonella cecal-culture-positive chicks was significantly lower (P < 0.01) at 10 days and 20 days of age in the chicks on used litter than in the chicks on new litter. The results indicated that newly hatched chicks reared on used litter had higher cecal VFA concentrations and higher resistance to Salmonella colonization than chicks reared on new litter.     

加工工艺参数对杀灭肉鸡饲料中沙门氏菌的影响

本试验目的是研究调质温度、时间和水分对杀灭肉鸡饲料中沙门氏菌数量级的影响,建立调质工艺杀灭饲料中沙门氏菌的数量级与温度、时间和水分等工艺参数间关系的数学模型,优化出杀灭饲料中4个数量级沙门氏菌的调质工艺参数。在实验室条件下,采用3因子3水平Box-Behnken模型的响应面设计。温度水平为60、80、100℃;时间水平为20、160、300s;水分水平为5%、10%、15%。温度越高,时间越久,水分越大,调质工艺杀灭饲料中的沙门氏菌的数量级越大。最大效应值为6.51,最小效应值为0.38,获得了相应的数学模型,研究还得到10组可以杀灭4个数量级沙门氏菌的调质工艺参数。这说明响应面设计可以应用于颗粒饲料加工过程中调质工艺参数的优化。试验结果表明,当调质温度为100℃,时间20s时,水分最少为13.78%;调质时间20s,水分15%时,温度最少应为95.2℃,这在实际肉鸡颗粒饲料加工中是可行的。     

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%).