Prevalence of antibodies to 'Mycoplasma synoviae' in laying hens and possible effects on egg shell quality

'Mycoplasma synoviae' ('M. synoviae') can cause respiratory disease, synovitis, or result in a silent infection in chickens and turkeys. The importance of 'M. synoviae' is well established in broilers but only a few studies have been conducted in layers. In the present study, the prevalence of 'M. synoviae' in commercial layer flocks was estimated using ELISA. For this study, 19 commercial layer flocks were selected randomly from New South Wales and Queensland region of Australia from producers who were willing to participate in the survey. Sixty eggs per flocks were randomly collected, out of these 30 eggs were used for ELISA and remaining 30 eggs were used to estimate various egg shell quality parameters. Subsequently, association between the serological status of eggs for 'M. synoviae' and egg shell quality was studied. In the flocks under study, seroprevalence of 'M. synoviae' was found to be high at 69% (95% confidence interval (CI) = 41.3-89.0). Statistical analysis showed an association between serological status for 'M. synoviae' and egg quality parameters such as translucency, shell breaking strength, % shell reflectivity and shell deformation. On the other hand, there was no significant association between serological status for 'M. synoviae' and other egg quality parameters such egg weight, egg shell weight, % egg shell or shell thickness

Prevalence of 'Mycoplasma synoviae' in eggs from laying hens using ELISA

'Mycoplasma synoviae' ('M. synoviae') can cause respiratory disease, synovitis, peritonitis, egg apical abnormalities or a subclinical infection. The importance of 'M. synoviae' is well established in broilers but only a few studies have been conducted in layers. In the present study, the prevalence of 'M. synoviae' in commercial layer flocks was determined by ELISA using egg yolk antibodies. Subsequently, a possible correlation between the serological status of 'M. synoviae' and egg shell quality was also studied. In the flocks under study, seroprevalence of 'M. synoviae' was found to be 69 % (95 % confidence interval (CI) = 47 to 91). Statistical analysis showed that the vaccinated group (3.0 ± 0.1) had the highest translucency score as compared to infected (2.4 ± 0.1) and uninfected (2.5 ± 0.1) groups, whereas % shell reflectivity was highest in the infected group (31.41 ± 0.3) as compared to the other two groups. Shell breaking strength (39.5 ± 0.5 Newtons) and shell deformation (298.7 ± 3.8 μm) values were significantly lower in the infected group than in the uninfected and vaccinated groups. There was no significant difference among these three groups for egg quality parameters egg weight, egg shell weight, % egg shell, shell thickness

Effect of egg washing and correlation between cuticle and egg penetration by various 'Salmonella' strains

In Australia, Europe and the United States, eggs and egg products are frequently associated with 'Salmonella' food poisoning outbreaks. Many of the egg-associated 'Salmonella' outbreaks have been due to the products such as mayonnaise, ice-cream and cold desserts which are eaten without cooking following the addition of raw egg. The ability of four 'Salmonella' isolates (one each of S. Singapore, S. Adelaide, S. Worthington and S. Livingstone) to penetrate washed and unwashed eggs using whole egg and agar egg penetration methods was investigated in the current study. The results of the agar penetration experiment indicated that all the isolates used in the present study have the capacity to penetrate the eggshell. Eggshell penetration by the S. Worthington isolate was higher but not significant (p = 0.06) in washed eggs compared to unwashed eggs. However, for all other isolates (S. Singapore, S. Adelaide andS. Livingstone), there was no significant difference in penetration of washed and unwashed eggs. Statistical analysis indicated that cuticle score was a significant linear predictor of Salmonella eggshell penetration.Whole egg penetration results showed that all of the 'Salmonella' isolates used in the present study were capable of surviving on the eggshell surface after 21 days of incubation (at 20 °C) following a high dose of inoculation (105 CFU/mL). The combined data of all isolates demonstrated that, the survival rate of 'Salmonella' on eggshells (inoculated with 105 CFU/mL)was significantly higher (p = 0.002) at 20 °C as compared to 37 °C. S. Singapore, S. Worthington, and S. Livingstone were not detected in egg internal contents whereas S. Adelaide was detected in one egg's internal contents

Effect of egg washing and correlation between eggshell characteristics and egg penetration by various Salmonella Typhimurium strains.

Salmonella is an important foodborne pathogen, causing an estimated 11,992 cases of infection in Australia per year. Egg or egg product related salmonellosis is a major concern for the egg industry. Worldwide, S. Typhimurium is one of the most common serovars identified in Salmonella food poisoning cases. The current study investigated the ability of five S. Typhimurium strains to penetrate washed and unwashed eggs using whole egg and agar egg penetration methods. All S. Typhimurium strains were able to penetrate eggshells and survive in egg albumen (at 20°C) according to whole egg penetration results. Polymerase Chain Reaction results demonstrated that S. Typhimurium strain 2 (10(3) and 10(5) CFU/mL), and strain 5 (10(3) and 10(5) CFU/mL) egg penetration was significantly higher (p<0.05) in washed eggs when compared to unwashed eggs. Statistical analysis of the agar penetration experiment indicated that S. Typhimurium was able to penetrate washed eggs at a significantly higher rate when compared to unwashed eggs (p<0.05). When compared to unwashed eggs, washed eggs also had significantly damaged cuticles. Statistical analysis also indicated that eggshell penetration by S. Typhimurium was related to various eggshell ultrastructural features such as cap quality, alignment, erosion, confluence, Type B bodies and cuticle cover

Survival of <i>Salmonella</i> Typhimurium strains on eggshell surface of unwashed eggs after 21 days of incubation: Comparison between 20°C and 37°C.

<p>ND: not detected.</p

Whole egg penetration by different <i>Salmonella</i> Typhimurium strains: Comparison between washed and unwashed eggs at 20°C.

<p>Whole egg penetration by different <i>Salmonella</i> Typhimurium strains: Comparison between washed and unwashed eggs at 20°C.</p

SEM image of damaged eggshell surface and exposed eggshell pore in washed eggs.

<p>SEM image of damaged eggshell surface and exposed eggshell pore in washed eggs.</p

SEM image of good quality mamillary caps with better confluence.

<p>SEM image of good quality mamillary caps with better confluence.</p

Relationship between eggshell ultrastructural parameters and penetration by <i>Salmonella</i> Typhimurium.

<p>Relationship between eggshell ultrastructural parameters and penetration by <i>Salmonella</i> Typhimurium.</p

Relationship between eggshell ultrastructural parameters and penetration by <i>Salmonella</i> Typhimurium.

<p>Relationship between eggshell ultrastructural parameters and penetration by <i>Salmonella</i> Typhimurium.</p