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Although deposition of Salmonella Enteritidis inside yolks is less common than deposition in albumen or on the vitelline (yolk) membrane in naturally contaminated eggs laid by infected hens, bacterial migration iflto the yolk to reach its nutrient-rich contents could lead to extensive multiplication. The present study used an in vitro egg contamination model to assess the ability of small initial numbers of Salmonella Enteritidis to penetrate the vitelline membrane and multiply inside yolks of eggs laid by 6 genetically distinct commercial lines of hens during 24 h of storage at 30°C. Eggs from each line were tested at 4 different hen ages by inoculation of approximately 100 cfu of Salmonella Enteritidis onto the outside of the vitelline membranes of intact yolks in plastic centrifuge tubes and then adding back the albumen into each tube before incubation. Overall, the frequency of penetration of Salmonella Enteritidis into the yolk contents of eggs from individual lines of hens ranged from 30 to 58% and the mean concentration of Salmonella Enteritidis in yolk contents after incubation ranged from 0.8 to 2.0 login cfu/mL. For both of these parameters, values for one hen line were significantly higher than for 2 other lines, but no other differences were observed. Hen age did not have a significant effect on egg yolk penetration by Salmonella Enteritidis. These results indicate that opportunities for the migration and growth of small initial numbers of Salmonella Enteritidis to attain more dangerous levels inside contaminated eggs during storage at warm temperatures can sometimes vary between different lines of laying hens. [ABSTRACT FROM AUTHOR]

Although Salmonella deposition inside yolks is uncommon in naturally contaminated eggs, migration through the vitelline membrane into the nutrient-rich yolk contents could enable rapid bacterial multiplication. Egg refrigeration restricts both penetration and growth, but a recently proposed national Salmonella Enteritidis control program would allow unrefrigerated ambient temperature storage of eggs on farms for up to 36 h. The present study used an in vitro egg contamination model to assess the ability of small numbers of 4 Salmonella Enteritidis strains and 4 Salmonella Heidelberg strains to penetrate the vitelline membrane and multiply inside yolks during 36 h of storage at either 20 or 30°C. After inoculation onto the exterior surface of the vitelline membrane, all 8 Salmonella strains penetrated to the yolk contents (at a mean frequency of 45.1%), and most strains grew to significantly higher levels (with a mean log10 bacterial concentration of 2.2 cfu/mL) during incubation at 30°C. Significant differences in penetration frequency and yolk multiplication were observed between individual strains and between serotypes (Salmonella Enteritidis > Salmonella Heidelberg for both parameters). Penetration and multiplication were significantly less frequent during incubation at 20°C. These results demonstrate that controlling ambient temperatures during prerefrigeration storage may be an important adjunct to prompt refrigeration for limiting Salmonella growth in eggs and thereby for preventing egg-transmitted human illness. [ABSTRACT FROM AUTHOR]

Eggs that harbor Salmonella in their edible contents pose a significant risk of transmitting disease to consumers. Although Salmonella deposition inside yolks does not usually occur at a high frequency in naturally contaminated eggs, bacterial penetration through the vitelline membrane could lead to rapid and extensive multiplication in the nutrient-rich yolk contents. The present study used an in vitro egg contamination model to assess the ability of Salmonella strains to penetrate the vitelline membrane and multiply inside yolks. An S. enteritidis strain and 2 Salmonella heidelberg strains, initially inoculated onto the outside of the vitelline membrane, were able to enter the yolk contents (at frequencies ranging from 10 to 25% of experimentally contaminated eggs) during 24 h of incubation at 30°C. Variants of these parent strains, obtained by in vivo passage into eggs laid by infected hens, penetrated the yolk membrane at significantly higher frequencies. These results demonstrate that pathogens such as S. enteritidis and S. heidelberg can penetrate into and begin to multiply inside the yolks of contaminated eggs during the first day of storage at warm temperatures. [ABSTRACT FROM AUTHOR]

Presents the mathematical relationships between beam vibration and the imposed launch loading. Background of the investigation; Analysis and modelling of profile-dependent loads; Total transient solution of Uniform Segments Method (USM); Two areas of concern in developing a gun model for use by the USM; Results of gun dynamic simulation of a hybrid launch; Conclusions.

An abstract of the article "Effect of passage through laying hens on organ invasiveness and phenotypic heterogeneity of Salmonella Enteritidis," by R.K. Gast and colleagues is presented.

The housing of laying hens is important for social, industrial, and regulatory aspects. Many studies have compared hen housing systems on the research farm, but few have fully examined commercial housing systems and management strategies. The current study compared hens housed in commercial cage-free aviary, conventional cage, and enriched colony cage systems. Environmental and eggshell pool samples were collected from selected cages/segments of the housing systems throughout the production cycle and monitored for Salmonella andCampylobacter prevalence. At 77 wk of age, 120 hens per housing system were examined for Salmonella and Campylobacter colonization in the: adrenal glands, spleen, ceca, follicles, and upper reproductive tract. All isolates detected from environmental swabs, eggshell pools, and tissues were identified for serotype. Two predominant Salmonella were detected in all samples: S. Braenderup and S. Kentucky. Campylobacter coli and C. jejuni were the only Campylobacter detected in the flocks. Across all housing systems, approximately 7% of hens were colonized withSalmonella, whereas > 90% were colonized with Campylobacter.Salmonella Braenderup was the isolate most frequently detected in environmental swabs (P < 0.0001) and housing system impactedSalmonella spp. shedding (P < 0.0001). Campylobacter jejuni was the isolate most frequently found in environmental swabs (P < 0.01), while housing system impacted the prevalence of C. coli and jejuni in ceca (P< 0.0001). The results of this study provide a greater understanding of the impact of hen housing systems on hen health and product safety. Additionally, producers and academia can utilize the findings to make informed decisions on hen housing and management strategies to enhance hen health and food safety. [ABSTRACT FROM AUTHOR]

Disease outbreaks can dramatically impact a producer's production schedule by disrupting the pullet movement into the hen house. One alternative is to early molt laying hens as they are coming into production. Early molted birds had lower production compared to controls with no differences in egg weight or egg components percentages. Bird welfare impacts were minimal as a result of the early molt. This management practice could be employed to allow pullets to be held minimizing production schedule disruptions as a result of a disease outbreak. [ABSTRACT FROM AUTHOR]

More than 90% of the commercial egg production in the United States is pledged to be in cage-free systems by 2025. Management practices like induced molting and litter area management have come under scrutiny because of the housing system change. The aim of this study was to determine the welfare and production implications of different litter substrates and also evaluate induced molting of hens in a cage-free system. Bovan White hens were housed in a multi-tier aviary system with daily access to open litter area of either Astroturf (AT), wood shavings (SH), or straw (ST) and bare concrete floor (CO) serving as control. At 68 wk of age, molt was induced in half of the hens whereas the other half continued without molting to 116 wk. Production and welfare parameters were measured periodically throughout first and second cycles. Litter substrate did not influence hen-day production and case-weight measurements. However, CO had the lowest total number of eggs produced during the first cycle (P < 0.05). Hen-day percentage was approximately 14% greater in molted hens during the second cycle with egg case weight being heavier in non-molt hens toward the end of second cycle (P < 0.05). The only welfare parameter influenced by litter substrate during the first cycle was a greater crop feather loss in AT than ST at mid-lay (P < 0.05). Keel deformations increased with age irrespective of the litter substrate with 91.5% of palpated hens having keel deformations at the end of first cycle (P < 0.05). Molting did not influence the keel palpation and footpad scores whereas frequency of moderate comb wound was greater in molt hens during molt (P < 0.05). Severe feather loss was seen in non-molt hens during the second cycle (P < 0.05). Litter substrate does not affect production and physical parameters of welfare of hens in a multi-tier aviary system. Additionally, induced molting can be successfully carried out in the multi-tier cage-free system. [ABSTRACT FROM AUTHOR]

In the United States, there is an increase in need for cage-free eggs in retail and food manufacturing sectors. Understanding the impact of cage-free systems and the corresponding management on egg quality is pertinent as the U.S. industry adapts existing housing and builds new cage-free housing structures. A study was conducted comparing 2 brown shell and 2 white shell hen strains housed in a cage-free aviary system. Each set of eggs were placed in cold storage and assessed at 0, 2, 4, 8, and 12 wk. Eggs were collected at 21, 31, 42, and 60 wk of hen age. A full profile of physical quality measurements was conducted on up to 18 intact eggs for each hen strain/egg storage/hen age combination. Egg weight increased approximately 10 g for brown shell and 14 g for white shell eggs as hens aged. Many of the properties monitored were significantly impacted by all 3 main effects (hen strain, egg storage, and hen age) resulting in 3-way interactions. A brown and a white shell strain had stronger shells (44 N; P < 0.0001) than the remaining brown and white shell strains (42 N and 39 N, respectively). The current study also determined volume of shell, total length, maximum width, and percent length at maximum width to more accurately indicate egg shape than shape index. One brown shell strain produced eggs with the most consistent shape characteristics over the hen ages monitored. White shell eggs from the cage-free aviary housing produced the highest whole-egg total solids between 31 to 60 wk of hen age, whereas brown shell eggs resulted in the most consistent level of whole-egg total solids (22–23.5%). The brown and white shell strains in the current study produce cage-free aviary eggs with distinctive physical quality attributes. The outcomes from this study can be utilized by the U.S. egg industry in planning management strategies and market placement of cage-free eggs. [ABSTRACT FROM AUTHOR]

Summary: The methanogenic endosymbionts of anaerobic protists represent the only known intracellular archaea, yet, almost nothing is known about genome structure and content in these lineages. Here, an almost complete genome of an intracellular Methanobacterium species was assembled from a metagenome derived from its host ciliate, a Heterometopus species. Phylogenomic analysis showed that the endosymbiont was closely related to free‐living Methanobacterium isolates, and when compared with the genomes of free‐living Methanobacterium, the endosymbiont did not show significant reduction in genome size or GC content. Additionally, the Methanobacterium endosymbiont genome shared the majority of its genes with its closest relative, though it did also contain unique genes possibly involved in interactions with the host via membrane‐associated proteins, the removal of toxic by‐products from host metabolism and the production of small signalling molecules. Though anaerobic ciliates have been shown to transmit their endosymbionts to daughter cells during division, the results presented here could suggest that the endosymbiotic Methanobacterium did not experience significant genetic isolation or drift and/or that this lineage was only recently acquired. Altogether, comparative genomic analysis identified genes potentially involved in the establishment and maintenance of the symbiosis, as well provided insight into the genomic consequences for an intracellular archaeum. [ABSTRACT FROM AUTHOR]

Hen housing for commercial egg production continues to be a societal and regulatory concern. Controlled studies have examined various aspects of egg safety, but a comprehensive assessment of commercial hen housing systems in the US has not been conducted. The current study is part of a holistic, multidisciplinary comparison of the diverse aspects of commercial conventional cage, enriched colony cage, and cage-free aviary housing systems and focuses on environmental and egg microbiology. Environmental swabs and eggshell pools were collected from all housing systems during 4 production periods. Total aerobes and coliforms were enumerated, and the prevalence of Salmonella and Campylobacter spp. was determined. Environmental aerobic and coliform counts were highest for aviary drag swabs (7.5 and 4.0 log cfu/mL, respectively) and enriched colony cage scratch pad swabs (6.8 and 3.8 log cfu/mL, respectively). Aviary floor and system wire shell pools had the greatest levels of aerobic contamination for all eggshell pools (4.9 and 4.1 log cfu/mL, respectively). Hens from all housing systems were shedding Salmonella spp. (89–100% of manure belt scraper blade swabs). The dry belt litter removal processes for all housing systems appear to affect Campylobacter spp. detection (0–41% of manure belt scraper blade swabs) considering detection of Campylobacter spp. was much higher for other environmental samples. Aviary forage area drag swabs were 100% contaminated with Campylobacter spp., whereas enriched colony cage scratch pads had a 93% positive rate. There were no differences in pathogen detection in the shell pools from the 3 housing systems. Results indicate egg safety is enhanced when hens in alternative housing systems use nest boxes. Additionally, current outcomes indicate the use of scratch pads in hen housing systems needs to be more thoroughly investigated for effects on hen health and egg safety. [ABSTRACT FROM PUBLISHER]

A move from conventional cages to either an enriched cage or a noncage system may affect the safety or quality, or both, of the eggs laid by hens raised in this new environment. The safety of the eggs may be altered either microbiologically through contamination of internal contents with Salmonella enterica serovar Enteritidis (Salmonella Enteritidis) or other pathogens, or both, or chemically due to contamination of internal contents with dioxins, pesticides, or heavy metals. Quality may be affected through changes in the integrity of the shell, yolk, or albumen along with changes in function, composition, or nutrition. Season, hen breed, flock age, and flock disease-vaccination status also interact to affect egg safety and quality and must be taken into account. An understanding of these different effects is prudent before any large-scale move to an alternative housing system is undertaken. [ABSTRACT FROM AUTHOR]

Floodwaters in New Orleans from Hurricanes Katrina and Rita were observed to contain high levels of fecal indicator bacteria and microbial pathogens. generating concern about long-term impacts of these floodwaters on the sediment and water quality of the New Orleans area and Lake Pontchartrain. We show here that fecal indicator microbe concentrations in offshore waters from Lake Pontchartrain returned to prehurricane concentrations within 2 months of the flooding induced by these hurricanes. Vibrio and Legionella species within the lake were more abundant in samples collected shortly after the floodwaters had receded compared with samples taken within the subsequent 3 months; no evidence of a long-term hurricane-induced algal bloom was observed. Giardia and Cryptosporidium were detected in canal waters. Elevated levels of fecal indicator bacteria observed in sediment could not be solely attributed to impacts from floodwaters, as both flooded and nonflooded areas exhibited elevated levels of fecal indicator bacteria. Evidence from measurements of Bifidobacterium and bacterial diversity analysis suggest that the fecal indicator bacteria observed in the sediment were from human fecal sources. Epidemiologic studies are highly recommended to evaluate the human health effects of the sediments deposited by the floodwaters. [ABSTRACT FROM AUTHOR]