The impact of different housing systems on egg safety and quality

Impacts of access to legume- or grass-based pasture on behaviour, physiological responses and bacterial load of laying hens

Despite the plethora of studies on the impacts of access to runs on chickens, there is a paucity of information on the welfare and behavioural repertoire of hens raised in the deep litter houses with or without access to legume- or grass-based pasture. Therefore, this study aimed to evaluate the impact of access to grass or legume pastures by laying hens on behaviour, physiological responses and bacterial load. The study was conducted to evaluate the influence of exposure of egg-type chickens to runs on grass or legume pastures on their welfare and behaviours. The study involved the use of 240 ISA brown pullets from 12 weeks of age and and lasted for 48 weeks. The treatments were deep litter housing with grass-based pasture run (PG), deep litter housing with legume-based pasture run (PL) and deep litter housing without runs (LD) having 80 pullets with four replicates of twenty birds each. Behavioural observations of the hens in each pen were made at 52 weeks of age and tonic immobility was assessed by making the birds lie on their back with their head resting in a U-shaped wooden cradle. The measurements of the respiratory rate and rectal temperature of the hens were assessed at 1:00 p.m. at different laying phases. The gastrointestinal and egg bacterial counts were conducted at 60 weeks of age. Results revealed that the proportion of time spent eating was highest (p < 0.05) in the deep litter housing system, while the legume and grass pasture were similar. The hens spent most of their time standing and eating in the three treatments. However, the time spent standing in PL and PG was similar but significantly higher (p < 0.05) than in LD. Results on tonic immobility duration showed that the time spent by the hens in LD during the reaction was significantly longer than those of the PL and PG in the first, second and third phases of the experiments. However, the time spent by the hens in PL and PG was similar. The rectal temperatures of PL and PG birds were comparable and higher than those of LD during the second phase. On the other hand, there was no difference in the respiratory rate. Plasma triiodothyronine (T3) of the hens did not follow a consistent pattern. The bacterial count in the large intestine in LD and PL was similar but significantly (P < 0.05) higher than that of the PG. It was concluded that access to pasture influenced the behaviours of hens and that tonic immobility duration was shorter in the hens on the pasture, suggesting that access to pasture favoured hens' welfare.

Knowledge and handling practices for raw hen's eggs during purchase, preparation, storage, and consumption: a cross sectional study

The study aimed to assess the hen's eggs knowledge, handling practices, and consumption among Palestinian consumers using the cross-sectional survey design. Online questionnaire was sent via social media platforms including well-known Facebook and WhatsApp groups in West bank, Gaza and Jerusalem, along with an invitation explaining the research objectives and the voluntary participation. The online questionnaire consisted of three main sections: socio demographic, knowledge and practices for hen's eggs during purchase, preparation, storage, and consumption. The items were developed based on previous literature and international guidelines for hen's eggs purchase and handling, and subjected to content validity process, followed by a pilot study to determine the reliability of the questionnaire using Cronbach's alpha test. The final data were analysed based on the dichotomous Rach model for knowledge and polytomous Rasch model for practices using Winsteps version 5.1.3. The Rasch SPSS output interval data files were used in the inferential analyses tests (one-way ANOVA test and independent samples t-test). The Rasch analysis showed that on average the participants had quite low level of knowledge of hen's eggs consumption safety, (person ability Mean 0.10 logit). The item difficulty measures ranged between + 1.65 (most difficult) and - 2.24 logit (easiest). It was not easy for the participants to endorse the items pertaining their practices in handling the hen's eggs during purchase, preparation, storage and consumption, (person ability Mean - 0.11 logit). The item difficulty measures ranged between + 2.68 logits (most difficult) to - 2.45 logit (easiest). In addition, female participants significantly outperformed males in knowledge scores; and the level of hen's eggs hygiene practices and storage during purchase depended on participants' knowledge level. The research recommended interventional programs to enhance Palestinians' awareness and knowledge about hen's eggs knowledge, handling practices, and consumption. Further quantitative and qualitative research studies were also recommended.

Salmonella in eggs and egg-laying chickens: pathways to effective control

Eggs contaminated with Salmonella have been internationally significant sources of human illness for several decades. Most egg-associated illness has been attributed to Salmonella serovar Enteritidis, but a few other serovars (notably S. Heidelberg and S. Typhimurium) are also sometimes implicated. The edible interior contents of eggs typically become contaminated with S. Enteritidis because the pathogen's unique virulence attributes enable it to colonize reproductive tissues in systemically infected laying hens. Other serovars are more commonly associated with surface contamination of eggshells. Both research and field experience have demonstrated that the most effective overall Salmonella control strategy in commercial laying flocks is the application of multiple interventions throughout the egg production cycle. At the preharvest (egg production) level, intervention options of demonstrated efficacy include vaccination and gastrointestinal colonization control via treatments such as prebiotics, probiotics, and bacteriophages, Effective environmental management of housing systems used for commercial laying flocks is also essential for minimizing opportunities for the introduction, transmission, and persistence of Salmonella in laying flocks. At the postharvest (egg processing and handling) level, careful regulation of egg storage temperatures is critical for limiting Salmonella multiplication inside the interior contents.

Listeria Occurrence in Conventional and Alternative Egg Production Systems

Listeria continues to be a persistent foodborne pathogen that is responsible for human cases of listeriosis when contaminated food products are consumed. Human subjects considered to be most susceptible include the elderly, immunocompromised, and pregnant women. Listeria is characterized as a saprophytic organism with the capability of responding and adapting to constantly changing environments because it possesses multiple stress response mechanisms to overcome varying temperatures, salt concentrations, and pH, among others. Primary foods and food products associated with listeriosis include dairy products and ready-to-eat meats such as turkey products. Historically, chicken eggs have not been identified as a primary source of Listeria, but the potential for contamination during egg production and processing does exist. Listeria species have been isolated from egg-processing plant equipment and are presumed to occur in egg-processing plant environments. Whether Listeria is consistently disseminated onto eggs beyond the egg-processing plant is a risk factor that remains to be determined. However, research has been conducted over the years to develop egg wash solutions that generate combinations of pH and other properties that would be considered inhibitory to Listeria. Even less is known regarding the association of Listeria with alternative egg production systems, but Listeria has been isolated from pasture flock broilers, so it is conceivable, given the nature of the outdoor environments, that layer birds under these conditions would also be exposed to Listeria and their eggs become contaminated. This review focuses on the possibility of Listeria occurring in conventional and alternative egg-laying production and processing systems.

Reproduction and production performance of improved chickens, their production constraints, and opportunities under Ethiopian conditions

Chickens have important roles in human food security and social and cultural values throughout the world. The current review focused on improved chickens' reproduction and production performance, their production constraints, and opportunities under Ethiopian conditions. The review covered nine performance traits, thirteen commercial breeds, and eight crossbreds between commercial breeds, and local chicken. The genotypes affected the age of the first egg, eggs per hen per year, and average egg weight. The three exotic breeds with short ages at first egg were Lohmann Brown, Novo Brown, and Potchefstroom Koekoek at 137, 140, and 142 days, respectively. The three genotypes with the highest egg production were Sasso T44, Bovans Brown, and Isa Browns laying 229, 235, and 276 eggs per hen per year. The three with the highest egg weight were Isa Browns, Bovans Brown, and Sasso T44 with their eggs weighing 58.8, 60.3, and 65.6 g each, respectively. Crossbreeding indigenous chicken with exotic breeds improved the age at first egg-lay, eggs per hen per year, and egg weigh. Crossbreeding indigenous chicken with exotic breeds shortened the age at first egg-lay. Crossbred of indigenous chicken with Fayoumi, Rhode Island Red, and White Leghorn reduced age at first egg-lay to 196.0, 198.3 and 224.3 days, respectively. Crossbreeding Dominant Red Barred with indigenous chicken reduced the age at first egg-lay from 137.3 to 130.7 days. Among the crossbred chicken, crossing between local chicken and Fayoumi, White Leghorn, and Yarkon laid the most eggs per hen per year being 119, 120, and 129 eggs, respectively. The crossbreed between Dominant Red Barred, and Horro ecotype aged 41-44 weeks laid eggs weighing 56.3 g. The management practices affected age at first egg with the smallholder production system tending to delay it and reduced the eggs per hen per year and average egg weight. The age at first egg-lay for Bovans Brown breed ranged from 165.6 to 196.2 days under this system. Potchefstroom Koekoek chicken breed reared under this system laid 130.5 to 187.0 eggs per hen per year. When additional feed was provided, Bovans Brown chicken breed increased their egg production from 133.5 to 235.9 eggs per hen per year. The average egg weight was 43.0, 52.1, and 52.5 g for Fayoumi, White Leghorn, and Rhode Island Red chicken, repectivelly, under this system in northern Ethiopia. Most chicken breeds were reared under inadequate management practices resulting in suboptimal performance. Crossbreeding exotic and indigenous chicken breeds and intensifying the management will improve performance. The existence of suitable market demand for chicken products, readily available commercial feeds, and government and private investor involvement are emerging opportunities for enhanced chicken performance in Ethiopia.

Management of the poultry red mite Dermanyssus gallinae with physical control methods by inorganic material and future perspectives

Poultry red mite (PRM), the ectoparasitic mite Dermanyssus gallinae found in laying hen farms, is a significant threat to poultry production and human health worldwide. It is a suspected disease vector and attacks hosts' other than chickens, including humans, and its economic importance has increased greatly. Different strategies to control PRM have been widely tested and investigated. In principle, several synthetic pesticides have been applied to control PRM. However, recent alternative control methods to avoid the side effects of pesticides have been introduced, although many remain in the early stage of commercialization. In particular, advances in material science have made various materials more affordable as alternatives for controlling PRM through physical interactions between PRM. This review provides a summary of PRM infestation, and then includes a discussion and comparison of different conventional approaches: 1) organic substances, 2) biological approaches, and 3) physical inorganic material treatment. The advantages of inorganic materials are discussed in detail, including the classification of materials, as well as the physical mechanism-induced effect on PRM. In this review, we also consider the perspective of using several synthetic inorganic materials to suggest novel strategies for improved monitoring and better information regarding treatment interventions.

Mislaying behavior detection in cage-free hens with deep learning technologies

Floor egg-laying behavior (FELB) is one of the most concerning issues in commercial cage-free (CF) houses because floor eggs (i.e., mislaid eggs on the floor) result in high labor costs and food safety concerns. Farms with poor management may have up to 10% of daily floor eggs. Therefore, it is critical to improving floor eggs management. Detecting FELB timely and identifying the reason behind its cause may address the issue. The primary objectives of this research were to develop and test a new deep-learning model to detect FELB and evaluate the model's performance in 4 identical research CF houses (200 Hy-Line W-36 hens per house), where perches and litter floor were provided to mimic commercial tiered aviary system. Five different YOLOv5 models (i.e., YOLOv5n, YOLOv5s, YOLOv5m, YOLOv5l, and YOLOv5x) were trained and compared. According to a dataset of 5400 images (i.e., 3780 for training, 1080 for validation, and 540 for testing), YOLOv5m-FELB and YOLOv5x-FELB models were tested with higher precision (99.9%), recall (99.2%), mAP@0.50 (99.6%), and F1-score (99.6%) than others. However, the YOLOv5m-NFELB model has lower recall than other YOLOv5-NFELB models, although it was tested with higher precision. Similarly, the speed of data processing (4%-45% FPS), and training time (3%-148%) were higher in the YOLOv5s model while requiring less GPU (1.8-4.8 times) than in other models. Furthermore, the camera height of 0.5 m and clean camera outperform compared to 3 m height and dusty camera. Thus, the newly developed and trained YOLOv5s model will be further innovated. Future studies will be conducted to verify the performance of the model in commercial CF houses to detect FELB.

Wind Speed and Landscape Context Mediate Campylobacter Risk among Poultry Reared in Open Environments

Foodborne pathogens cause over 9 million illnesses in the United States each year, and Campylobacter from chickens is the largest contributor. Rearing poultry outdoors without the use of antibiotics is becoming an increasingly popular style of farming; however, little is understood about how environmental factors and farm management alter pathogen prevalence. Our survey of 27 farms in California, Oregon, Washington, and Idaho, USA, revealed a diversity of management practices used to rear poultry in the open environment. Here, we assess environmental and management factors that impact Campylobacter spp. prevalence in 962 individual chicken fecal samples from 62 flocks over a three-year period. We detected Campylobacter spp. in 250/962 (26.0%) of fecal samples screened, in 69.4% (43/62) of flocks, and on 85.2% (23/27) of farms. We found that Campylobacter spp. prevalence was predicted to increase in poultry on farms with higher average wind speeds in the seven days preceding sampling; on farms embedded in more agricultural landscapes; and in flocks typified by younger birds, more rotations, higher flock densities, and the production of broilers. Collectively, our results suggest that farms in areas with higher wind speeds and more surrounding agriculture face greater risk of Campylobacter spp. introduction into their flocks.

Prebiotics can restrict Salmonella populations in poultry: a review

Antibiotics were over the years, the common supplement used for poultry production. There is a global trend to lessen antibiotics' use due to the contamination of consumed meat with antibiotic residues. Also, there is a concern that human treatments might be jeopardized due to the emergence of antibiotic-resistant bacteria. Prebiotics are attractive supplements, particularly in poultry production, because of the diversity of their effects, including pH amendments, production of short-chain fatty acids (SCFA) and the inhibition of pathogens' growth. The commonly used prebiotics are carbohydrate sources that cannot be easily broken down by chickens. However, they can efficiently be utilized by the intestinal tract's microflora. Oligosaccharides, polysaccharides and lactose are non-digestible carbohydrate sources that are typically used in poultry diets as prebiotics. This review covers current applications and prospects for using prebiotics to improve poultry performance and reduce pathogens, particularly Salmonella, in gastrointestinal tract.

Scale Difference from the Impact of Disease Control on Pig Production Efficiency

Epidemic disease prevention plays a critical role in ensuring the healthy development of livestock farming, and the subjective willingness of breeders can be affected by the cost of epidemic disease prevention. To correct the misconception that farmers regard the cost of disease control as an ineffective cost, and to promote the healthy development of the pig breeding industry, our study employed the data envelopment analysis super-efficiency model and panel threshold regression model to evaluate the combination of the cost of epidemic disease prevention and swine productivity using data collected from 1998-2018 across 30 provinces in China. The following results were obtained. (1) The cost of epidemic disease prevention generated a non-linear on swine productivity when the swine farming scale was limited; (2) When the number of animals at the beginning of the year was less than 6.0002, swine productivity was impacted negatively; (3) When the number of animals at the beginning of the year ranged between 6.0002 and 12.9994, the impact was insignificant; (4) A strong correlation was observed between the expenses of epidemic disease prevention and animal productivity when the number of animals at the beginning of the year exceeded 12.9994. These results indicate that publicity should be enhanced to elucidate the combination of epidemic disease prevention and swine productivity among breeders. In addition, the government should introduce relevant policies to encourage the development of large-scale pig farming, such as subsidies for the construction of large-scale farms and insurance.

Potential Health Effects of Heavy Metals and Carcinogenic Health Risk Estimation of Pb and Cd Contaminated Eggs from a Closed Gold Mine Area in Northern Thailand

Gold-mining activities have been demonstrated to result in significant environmental pollution by Hg, Pb, and Mn, causing serious concerns regarding the potential threat to the public health of neighboring populations around the world. The present study focused on heavy-metal contamination in the eggs, blood, feed, soil, and drinking water on chicken farms, duck farms, and free-grazing duck farms located in areas < 25 km and > 25 km away from a gold mine in northern Thailand. In an area < 25 km away, Hg, Pb, and Mn concentrations in the eggs of free-grazing ducks were significantly higher than > 25 km away (p < 0.05). In blood, Hg concentration in free-grazing ducks was also significantly higher than those in an area > 25 km away (p < 0.05). Furthermore, the Pb concentration in the blood of farm ducks was significantly higher than in an area > 25 km away (p < 0.05). The concentration of Cd in drinking water on chicken farms was significantly higher for farms located within 25 km of the gold mine (p < 0.05). Furthermore, a high correlation was shown between the Pb (r2 = 0.84) and Cd (r2 = 0.42) found between drinking water and blood in free-grazing ducks in the area < 25 km away. Therefore, health risk from heavy-metal contamination was inevitably avoided in free-grazing activity near the gold mine. The incremental lifetime cancer risk (ILCR) in the population of both Pb and Cd exceeded the cancer limit (10−4) for all age groups in both areas, which was particularly high in the area < 25 km for chicken-egg consumption, especially among people aged 13−18 and 18−35 years old. Based on these findings, long-term surveillance regarding human and animal health risk must be strictly operated through food chains and an appropriate control plan for poultry businesses roaming around the gold mine.

The Occurrence of Lead in Animal Source Foods in Iran in the 2010s Decade: A Systematic Review

Lead is a toxic, non-biodegradable, and accumulative heavy metal released into the environment by natural and anthropogenic activities. Despite health concerns due to the consumption of lead-contaminated foods, no systematic and comprehensive review studies have been published about the lead occurrence in animal source foods in Iran. The present study aimed to review the papers investigating the Pb contamination in animal-based food groups (including meat, fish, milk and dairy products, egg and honey) in Iran. A comprehensive search was performed with selected keywords in databases of Scopus, Web of science, and Magiran to find articles that had been published from January 2010 to December 2019. Of 371 identified articles on Pb contaminations in foods, 60 articles were selected using PRISMA. The lead concentrations were higher than the maximum recommended limits in 3 of 9 studies on meat and meat products, 12 of 26 studies on fish and canned fish, and 5 of 18 studies on milk and dairy products. However, the Pb contamination observed in studies on honey and egg was not comparable due to the lack of national and international standards. These results represent the importance of environmental monitoring and assessment for reducing exposure of animals to Pb, resulting in an improvement of food safety.

Health significant alarms of toxic carcinogenic risk consumption of blood meal metals contamination in poultry at a gold mining neighborhood, northern Thailand

The proposes of this study were to compare THg (total mercury), Pb(Lead), Cd(Cadmium), and Mn (Manganese) contamination in poultry blood between polluted areas (≤ 25 km) and unpolluted areas (> 25 km) adjacent to the largest gold mining in northern Thailand. The THg level in the free-grazing duck in polluted areas was significantly higher than unpolluted area. Both THg and Pb levels in free-grazing duck were also highest in polluted areas. In contrast, the level of (Mn) in chicken blood was the highest in polluted areas. Cadmium in farmed duck from polluted areas was significantly higher than unpolluted areas. The target hazard quotient (THQ) and hazard index (HI) of Hg, Pb, Cd, and Mn in all age groups in both areas did not exceed 1, meaning there is no possibility of the non-carcinogenic toxicity. Whereas, the incremental lifetime cancer risk (ILCR) of both Pb and Cd exceeded 1 × 10^-4 in all age groups and these were particularly higher in the polluted area and considered to yield significant health effects of increasing the cancer risk. The ILCR in descending order for Pb and Cd was 13-18 years old = 18-35 years old > 6-13 years old = 35-65 years old > 3-6 years old > 65 up years old, respectively. The results revealed that the human cancer risk related to consuming poultry blood contaminated with both Pb and Cd in all age groups must be of concern, especially 13-18 and 18-35 years, it must be recommended to avoid raising animals in contaminated areas, especially free-grazing duck.

Microbiome Applications for Laying Hen Performance and Egg Production

Management of laying hens has undergone considerable changes in the commercial egg industry. Shifting commercial production from cage-based systems to cage-free has impacted the housing environment and created issues not previously encountered. Sources of microorganisms that become established in the early stages of layer chick development may originate from the hen and depend on the microbial ecology of the reproductive tract. Development of the layer hen GIT microbiota appears to occur in stages as the bird matures. Several factors can impact the development of the layer hen GIT, including pathogens, environment, and feed additives such as antibiotics. In this review, the current status of the laying hen GIT microbial consortia and factors that impact the development and function of these respective microbial populations will be discussed, as well as future research directions.

Effect of housing environment and hen strain on egg production and egg quality as well as cloacal and eggshell microbiology in laying hens

This study was conducted to determine the effect of housing environment and laying hen strain on performance, egg quality, and microbiology of the cloaca and eggshell. A total of 1,152 Hy-Line Brown (HB) and Hy-Line W-36 White Leghorn (W-36) hens were used. All hens were kept in conventional cages (CC) from 18 to 32 wk of age and then moved to either enriched colony cages (EC) or free-range (FR) pens or continued in CC. Hens were randomly allocated into a 2 × 3 factorial arrangement of 2 laying hen strains (brown and white) and 3 housing environments (CC, EC, and FR) in a split plot in time (hen age) design. The experiment was conducted from 32 to 85 wk of age. The experiment was divided into 2 phases: early phase (32-51 wk of age) and late phase (52-85 wk of age). A 3-way interaction was observed for hen day egg production (HDEP) among housing environments, hen strain, and bird age in the early phase (P = 0.004) as well as in the late phase (P < 0.0001). In both of the phases, HDEP was higher in CC and FR than in EC. Hy-Line W-36 hens raised in EC had the lowest HDEP compared to other treatments. A 3-way interaction was observed for feed intake (FI; P = 0.017) and feed conversion ratio (FCR) in the late phase (P < 0.0001). The lowest FI and highest FCR were observed in EC for W-36 hens. Free-range hens performed in-between for eggshell quality when compared to CC and EC while HB had better egg quality than W-36. Free-range hens had higher cloacal bacterial counts for aerobes, anaerobes, and coliforms than CC and EC. Higher eggshell bacterial contamination was observed in eggs from FR versus eggs from CC and EC. These results indicate that both housing environment and laying hen strain affect performance and egg quality as well as cloacal and eggshell microbiology. Further studies should be conducted to determine food safety and economic impacts when using different hen strains and housing environments.

Productive parameters in three production models: floor, cage and grazing in layer poultry in Ocaña Norte de Santander

ABSTRACT The objective was to evaluate the three housing systems in laying birds to determine animal welfare and productivity parameters of the Isa Brown line. 135 laying hens distributed in 45 hens were used for each exploitation system; the managed feeding was 114gr/bird/day in the floor and cage systems for the entire trial period, for the grazing system 14 gr less of concentrate were used; the study had a duration of 8 weeks, of which the first was for accustoming and 7 for testing; At the end of each week, 9 eggs were collected to be studied and analyzed in the animal nutrition laboratory, using 3 eggs for each housing system. The information obtained was analyzed using SPSS for each variable. The parameters of production, consumption, feed conversion, and egg weight, were evaluated; where one-factor ANOVA and Tukey HSD test and least significant difference. The percentage production was no significant difference between the three cage floor and grazing production models being (P-Value <0.05), for the food consumption parameter there is a significant difference (P-Value> 0.05) for each housing system (34.54 ± 6.93), also happened with the conversion variable between the floor, cage production models with the grazing one (1.93 ± 0.6), for the egg weight they were similar in all housing systems (61.1 g in cage, 60.8 g in floor and 60.6 g in grazing) where there were no significant differences. In conclusion, birds with a lower housing density allow better behavior, which is an indicator of comfort, generating higher productivity.

Research Note: Contamination of eggs by Salmonella Enteritidis and Salmonella Typhimurium in experimentally infected laying hens in indoor cage-free housing

Contaminated eggs are a leading source of human Salmonella infections and this problem continues to challenge public health authorities and egg industries around the world. Salmonella invasion of the ovaries and oviducts of infected laying hens can result in bacterial deposition inside the edible portions of developing eggs. The introduction, persistence, and transmission of salmonellae in commercial egg-laying flocks are influenced by flock management practices, but the food safety ramifications of different types of laying hen housing remain unresolved. The present study assessed the frequency of internal contamination of eggs after experimental Salmonella Enteritidis and S. Typhimurium infection of laying hens in indoor cage-free housing. Groups of 72 hens were housed on wood shavings in isolation rooms simulating commercial cage-free barns with community kick-out nest boxes and perches and 1/3 of the hens in each room were orally inoculated with 8.0 × 10⁷ cfu of 2-strain mixtures of either S. Enteritidis (2 rooms) or S. Typhimurium (2 rooms), and the entire internal contents of all eggs laid 5 to 30 d postinoculation in nest boxes or on the flooring substrate were cultured to detect Salmonella. Contaminated eggs were laid between 8 and 28 d postinoculation. The overall incidence of S. Enteritidis isolation from eggs (3.41%) was significantly (P = 0.0005) greater than S. Typhimurium (1.19%). The contamination frequencies associated with the 2 egg collection locations were not significantly different (P > 0.05). These results demonstrate that oral infection of a relatively small proportion of laying hens in indoor cage-free housing with invasive Salmonella serovars can result in the production of internally contaminated eggs at low frequencies over a period of nearly a month postinoculation.

Prebiotics and alternative poultry production

Alternative poultry production systems continue to expand as markets for organic and naturally produced poultry meat and egg products increase. However, these production systems represent challenges associated with variable environmental conditions and exposure to foodborne pathogens. Consequently, there is a need to introduce feed additives that can support bird health and performance. There are several candidate feed additives with potential applications in alternative poultry production systems. Prebiotic compounds selectively stimulate the growth of beneficial gastrointestinal microorganisms leading to improved health of the host and limiting the establishment of foodborne pathogens. The shift in the gastrointestinal microbiota and modulation of fermentation can inhibit the establishment of foodborne pathogens such as Campylobacter and Salmonella. Both current and potential applications of prebiotics in alternative poultry production systems will be discussed in this review. Different sources and types of prebiotics that could be developed for alternative poultry production will also be explored.

Effect of laying hens age and housing system on physicochemical characteristics of eggs

In this study, the objective was to evaluate the effect of the age of Hy-line Brown hens – 44 and 60 weeks of age (26 and 42 weeks of laying) and housing system (enriched cages and litter) on the quality of eggs. According to our results, eggs with a better quality of albumen were obtained from younger hens than from older hens. Moreover, older hens produced eggs with inferior quality related to shell parameters, such as greater elastic deformation, poorer breaking strength, and thinner shells. However, hens kept in a litter housing system laid eggs with superior shell quality characteristics of less flexible and greater breaking strength, even though the thickness, weight, and percentage were similar in both housing systems. In addition, a higher amount and activity of lysozyme were obtained from eggs laid by hens kept in the litter housing system than those obtained from hens kept in cages. The maintenance system and age of birds also had a significant (P≤0.05) effect on the basic chemical composition of eggs, as well as on the proportion of individual elements and fatty acid profile. Taking these results into account, we can conclude that the more valuable characteristics from the morphological and nutritional point of view were observed in eggs obtained from younger Hy-line hens kept in the litter housing system.

Guinea fowl (Numida meleagris) eggs and free-range housing: a convenient alternative to laying hens' eggs in terms of food safety?

The aim of this study was to evaluate the impact of the genotype (guinea fowl, native breed Leghorn, and commercial hybrid hens), storage time (0, 14, 28 d) and storage temperature (fresh, 5, 20°C) on eggshell quality traits and microbiological contamination of eggshell, eggshell membranes, and albumen. A total of 150 hens (50 hens per genotype—divided into 2 equal groups because of the results replication) were used. There were 150 eggs (50 per genotype) used for microbial analysis and 600 eggs used for the analysis of eggshell quality. The effects of genotype, storage time, and storage temperature were observed. Moreover, interactions between these factors were calculated. The significant effect of genotype (P = 0.0001) was found in egg weight, in all observed parameters of eggshell quality (proportion, thickness, strength, surface, and index), eggshell contamination of Escherichia coli (EC) and total number of micro-organisms (TNM), penetration of TNM into eggshell membranes (P = 0.0014), and penetration of TNM into albumen (P = 0.0019). Storage time significantly affected egg weight and all parameters of eggshell quality except the eggshell strength and index. It also significantly affected count of Enterococcus (ENT) on eggshell, TNM in eggshell membranes and TNM in albumen. Storage temperature significantly influenced egg weight (P = 0.0001) and all parameters but eggshell thickness and surface. Regarding the microbial contamination, storage temperature significantly affected a count of ENT on shell, TNM in shell membranes, and TNM in albumen. Concerning significant interactions, the interaction among genotype and storage time was found significant (P = 0.0148). Fresh and 28-day-old commercial hybrid eggs were the most contaminated, whereas guinea fowl eggs (fresh and 14 d old) and Leghorn hen eggs (fresh, 14, 28 d old) had the lowest level of contamination by EC. When looking for an alternative to laying hens, guinea fowls should be taken into consideration due to their higher resistance to diseases, ability of adaptation to different environmental conditions, and especially in terms of eggshell quality and therefore egg safety.

Combined Effect of Genotype, Housing System, and Calcium on Performance and Eggshell Quality of Laying Hens

Simple Summary

Hen performance and eggshell quality are affected by a wide range of factors from which genotype. The housing conditions and feed calcium (Ca) level might be considered the most important. Here, we compared the performance and eggshell quality of commercial hybrids (ISA Brown, Bovans Brown) and traditional Czech hybrid (Moravia BSL). Laying hens were housed in enriched cages and on littered pens and fed two different Ca levels (3.00% vs. 3.50%). Contrary to the commercial hybrids, Moravia BSL performed better under the lower feed Ca level in enriched cages. Additionally, the data pointed out the importance of studying the interaction between factors, which might help to decide the best housing system and feed Ca level for a certain hen genotype.

Abstract

The objective of this study was to evaluate hen performance and eggshell quality response to genotype, housing system, and feed calcium (Ca) level. For this purpose, an experiment was conducted on 360 laying hens of ISA Brown, Bovans Brown (commercial hybrids), and Moravia BSL (traditional Czech hybrid). Laying hens were kept in enriched cages and on littered floor and fed similar feed mixtures with different Ca content (3.00% vs. 3.50%). In terms of hen performance, ISA Brown had the highest egg production (84.2%) compared to Moravia BSL (74.3%) and Bovans Brown (71.4%). Regarding eggshell quality, Bovans Brown showed the highest values of all eggshell quality parameters. Increasing feed Ca level augmented egg production (p ≤ 0.001) but had no effect on other performance parameters. Except eggshell thickness, all eggshell quality parameters were affected by the three-way interaction of genotype, housing, and Ca. Bovans Brown, which had the strongest eggshells (5089 g/cm²) when housed on a littered floor system and fed 3.00% Ca, while Moravia BSL housed on a littered floor had the weakest eggshells (4236 g/cm²) at 3.50% Ca. The study pointed out the importance of the interactions between studied factors on performance and eggshell quality compared to an individual factor effect.

Strategies to Improve Poultry Food Safety, a Landscape Review

Food safety remains a significant public health issue for the poultry industry. Foodborne pathogens can be in contact at all phases of poultry production, from initial hatch to processing and ultimately to retail and meal preparation. Salmonella and Campylobacter have been considered the primary foodborne pathogens associated with poultry. Both organisms are major causative agents of human foodborne illness. Limiting these pathogens in poultry production requires identifying their sources and routes of transmission. This involves the ability to isolate and precisely identify them using methodologies capable of discernment at the genome level. Interventions to reduce their occurrence in poultry production employ two basic strategies: prevention of establishment and elimination of already-established pathogens. This review provides an overview of current findings and prospects for further research on poultry food safety issues.

Pb, Cd, and Cu Play a Major Role in Health Risk from Contamination in Duck Meat and Offal for Food Production in Thailand

Zinc, Pb, Cd, Mn, Fe, Cr, and Cu levels in duck meat from large-scale farms have been found to be significantly higher than those from free-grazing duck farms. Zinc, Co, Mn, Cr, and Cu contamination levels in duck liver from large-scale farms were significantly higher than those from free-grazing farms; only Cd in duck liver from free-grazing farms was higher than in liver samples from large-scale farms at P < 0.05. Lead, Cd, Fe, and Cr levels in duck intestine samples from free-grazing farms were higher than large-scale farms at P < 0.001. Moreover, the average concentrations of Pb in duck meat and liver samples from large-scale farms and Cd levels in duck liver samples from free-grazing farm also exceeded the FAO/WHO and Codex Alimentarius limits by 100% (55/55), 100% (54/54), and 67.6% (23/34), respectively. PCA analysis showed a strong positive relationship between the eight metals in meat, liver, and intestine was > 0.69, > 0.69, and > 0.72, in order. The relationship of the liver combined with the intestine was > 0.65. This study indicated that consumers may incur health risks from long-term consumption of duck due to high Pb and Cd concentrations from both types of farms, particularly from large-scale duck farms.

Sustainability and Quality Aspects of Different Table Egg Production Systems: A Literature Review

Eggs are of considerable importance in feeding the population, as they are a relatively inexpensive and complex food source of very high biological value. The daily animal protein requirement for the human body can be covered with eggs in the cheapest way and with the lowest environmental impact. As animal welfare, as well as environmental and health awareness issues, become increasingly prominent in developed countries, consumer demand for eggs has also changed significantly in recent years, with an increasing number of consumers buying eggs produced in non-cage housing systems. In recent years, cage housing has been more frequently debated in EU member states. An initiative was launched in 2018 to end cage housing technologies and the sale of eggs produced in this way. However, in addition to animal welfare, a number of other factors need to be considered in relation to sustainable production. For this reason, the aim of this research is to provide a comprehensive overview of the sustainability issues of various housing technologies, as well as quality factors affecting consumer health and egg consumption based on the relevant international references and databases. Although there is a growing demand for products produced in non-cage housing systems due to the increasing relevance of environmental protection, health awareness and animal welfare issues in Western societies, research has shown that non-caged production is not the best solution for environmentally, socially and economically sustainable egg production.

Pooling of Laying Hen Environmental Swabs and Efficacy of Salmonella Detection

ABSTRACT

Environmental testing for Salmonella Enteritidis is required for U.S. shell egg producers with ≥3,000 hens on a farm. The egg producer assumes all costs for the mandatory testing. According to the U.S. Food and Drug Administration (FDA) Egg Rule, either manure scraper or drag swabs can be collected according to published guidelines and requirements. The present study was undertaken to determine the efficacy of Salmonella detection with one-, two-, and four-swab pools of either manure scraper or drag swabs. Resistant isolates of Salmonella serovars Enteritidis (1,000 ppm of streptomycin), Heidelberg (200 ppm of nalidixic acid [NA]), Typhimurium (200 ppm of NA), and Kentucky (200 ppm of NA) were utilized. Low (approximately 8.4 CFU) and high (approximately 84 CFU) levels of inocula were introduced onto a single swab within a pool. Single flocks from each conventional cage (manure scraper swabs) and cage-free barn (drag swabs) were monitored throughout the study at the ages required under the FDA Egg Rule. The highest and most consistent recovery of inoculum was found in single swab samples. For low dose inocula, recovery of isolates was low from single manure scraper swabs (57.9 to 29.2%) and decreased as more swabs were added to the pool. Recovery of isolates from manure scraper swabs was higher for high dose inocula, although Salmonella Heidelberg was outcompeted by the naturally occurring flora and had the lowest rate of recovery among the isolates tested. One- and two-swab pools of drag swabs had similar rates of recovery at both low and high doses for Salmonella Enteritidis, Salmonella Heidelberg, and Salmonella Typhimurium. When Salmonella Enteritidis and Salmonella Kentucky were combined in an inoculum, Salmonella Enteritidis was recovered at a much higher rate than was Salmonella Kentucky for all types of swabs and doses of inocula. Pooling of two drag swabs allowed for similar detection of low and high dose Salmonella, but the pooling of manure scraper swabs decreased detection of low dose Salmonella.

HIGHLIGHTS

Rapid detection of Salmonella in poultry environmental samples using real-time PCR coupled with immunomagnetic separation and whole genome amplification

We evaluated the combination of immunomagnetic separation (IMS), multiple displacement amplification (MDA), and real-time PCR to detect Salmonella from poultry environmental samples. The limits of detection (LODs) of IMS-MDA real-time PCR with different culture enrichment hours (0, 4, 6, and 8 h) were determined in artificially inoculated litter samples from a specific pathogen-free (SPF) poultry farm. In addition, Salmonella detection rate of IMS-MDA real-time PCR with 8-h culture enrichment was compared with that of conventional real-time PCR and culture-based detection by analyzing 174 poultry environmental samples (boot swabs, drag swabs, and litter), and the levels of Salmonella in the samples were quantified using the most probably number method. The LODs of IMS-MDA real-time PCR with 0, 4 to 6, and 8-h enrichment were 10, 1, and 0.1 CFU/g, respectively. Salmonella was detected in 25 of the 174 environmental samples (14.4%) by IMS-MDA real-time PCR, compared with 24 (13.8%) by conventional real-time PCR and 19 (10.9%) by culturing. Cohen's kappa index indicated strong concordance (0.79) between IMS-MDA real-time PCR and culture detection. We demonstrated the potential of the IMS-MDA real-time PCR assay as a faster and more sensitive alternative to culture-based Salmonella detection from poultry environmental samples.

Gastrointestinal microbiomes of broilers and layer hens in alternative production systems

Alternative poultry production systems consisting of free-range or pasture flock raised poultry continues to increase in popularity. Based on the perceived benefits of poultry products generated from these alternative poultry production systems, they have commercial appeal to consumers. Several factors impact the health and well being of birds raised and maintained in these types of production systems. Exposure to foodborne pathogens and potential for colonization in the gastrointestinal tract has to be considered with these types of production systems. The gastrointestinal tract microbial composition and function of birds grown and maintained in alternative poultry operations may differ depending on diets, breed, and age of bird. Dietary variety and foraging behavior are potential influential factors on bird nutrition. The gastrointestinal tract microbiomes of birds raised under alternative poultry production systems are now being characterized with next-generation sequencing to identify individual microbial members and assess the impact of different factors on the diversity of microbial populations. In this review, the gastrointestinal tract microbiota contributions to free-range or pasture-raised broiler and egg layer production systems, subsequent applications, and potential future directions will be discussed.

Contamination of eggs by Salmonella Enteritidis in experimentally infected laying hens of four commercial genetic lines in conventional cages and enriched colony housing

Human illness caused by the consumption of eggs contaminated with Salmonella Enteritidis is a continuing international public health concern. This pathogen is deposited inside the edible contents of eggs as a consequence of its ability to colonize reproductive tissues in infected hens. Conditions in the housing environment can influence the persistence and transmission of avian Salmonella infections, but the food safety ramifications of different poultry management systems are not entirely clear. The present study assessed the deposition of S. Enteritidis inside eggs laid by groups of experimentally infected laying hens of 4 commercial genetic lines (designated as white egg lines W1 and W2 and brown egg lines B1 and B2). Groups of hens from each line were housed at 555 cm2 of floor space per bird in both conventional cages and colony units enriched with access to perches and nesting areas. All hens were orally inoculated with 5.75 × 107 cfu of a 2-strain S. Enteritidis mixture, and the internal contents of eggs laid 5 to 24 D post-inoculation were cultured to detect the pathogen. No significant differences in egg contamination frequencies were found between the 2 housing systems for any of the hen lines. Contaminated eggs were laid between 7 and 21 D post-inoculation at an overall frequency of 2.47%, ranging from 0.25 to 4.38% for the 4 hen lines. The frequency of S. Enteritidis recovery from egg samples was significantly (P < 0.05) lower for line B2 than for any of the other lines, and the egg contamination frequency for line W1 was significantly greater than for line W2. The overall incidence of contamination among white eggs (3.38%) was significantly higher than among brown eggs (1.56%). These results demonstrate that S. Enteritidis deposition inside eggs can vary between genetic lines of infected laying hens, but housing these hens in 2 different systems did not affect the production of contaminated eggs.

Prevalence and Genetic Analysis of Salmonella enterica from a Cross-Sectional Survey of the New Zealand Egg Production Environment

Epidemiological evidence suggests that Salmonella on New Zealand eggs is not an important pathway for human salmonellosis. However, robust nationally representative data for Salmonella contamination of eggs is not available to support this. To better understand the exposure of New Zealand commercial eggs to Salmonella, a cross-sectional survey collected data on prevalence and serotypes of Salmonella in the feed, laying sheds (feces, dust, and boot or manure belt swabs), and packhouses (egg contact surfaces) of New Zealand commercial egg layer farms. Salmonella was not detected on 16 of 28 surveyed farms, and 4 farms had only one positive sample. Of the 43 (13.3%) of 323 Salmonella-positive samples, dust samples had the highest prevalence (19 of 67, 28.4%), followed by boot or manure belt swabs (11 of 67, 16.4%), feces (7 of 67, 10.4%), packhouse egg contact surfaces (5 of 87, 5.7%), and feed (1 of 33, 3.0%). A significantly higher prevalence was from caged (33 of 75, 44.0%; P < 0.001) compared with cage-free (4 of 126, 3.2%) systems, yet multiple practices differ between laying systems, which could influence prevalence. Salmonella-positive packhouse samples were only identified on the three farms with the highest laying shed prevalence, and isolates were genetically related (as determined by single nucleotide polymorphism analyses) suggesting cross-contamination between the laying shed and packhouse surfaces. Serotypes isolated included Salmonella Infantis, Salmonella Thompson, Salmonella Typhimurium, Salmonella Anatum, and Salmonella Mbandaka. Importantly, Salmonella Enteritidis, which causes egg-associated outbreaks internationally, was not isolated. Genomic comparisons of isolates supported the presence of a common contamination source in the shed and farm environments rather than multiple sporadic contamination events. This survey establishes a benchmark of Salmonella prevalence and types in the New Zealand egg production environment and provides a reference point for assessing the impact of changes to practices on Salmonella prevalence.

The influence of the conditions of acquisition and storage of table eggs on changes in their quality and the presence of mycobiota and Fusarium mycotoxins

The study showed that the hen housing system and egg storage conditions had significant influence on differences in the qualitative traits of eggs. The most rapid qualitative traits changes were observed in the eggs laid by the hens kept in the free-range and litter systems. After the first week of storage fungi were found on the eggshell surface but significant growth of fungi on the eggshell surface was noted after 3 wk, regardless of the storage conditions. Higher humidity during egg storage causes the dynamic development of fungi in the albumen. The principal component analysis proved the dependency between ergosterol and the trichothecene concentration in the albumen. Mycotoxins in the albumen indicate the presence of pathogenic species of microscopic fungi. The albumen of the eggs laid by the hens kept in cages had the lowest concentration of mycotoxins. The results of the study showed that the conditions of the henhouse environment significantly influenced the initial contamination of eggshells. Egg storage conditions, i.e., high air humidity, favor the development of fungi on the eggshell surface, affect the dynamics of fungal growth into the albumen and the production of mycotoxins.

Prevalence, Persistence, and Antimicrobial Resistance of Campylobacter spp. from Eggs and Laying Hens Housed in Five Commercial Housing Systems

Husbandry practices for laying hens in commercial egg production is a topic of interest from a social, economic, and regulatory standpoint. Animal welfare concerns regarding the use of conventional cages have arisen and consumer perceptions of hen welfare have led to a higher demand for cage-free eggs. The aim of this study was to assess the impact of housing systems on prevalence, persistence, and antimicrobial resistance (AMR) of Campylobacter from laying hens and shell eggs. A total of 425 samples were collected over a 10-month period from the North Carolina Layer Performance and Management Test and Campylobacter isolates were identified by serological, biochemical, and molecular tests. Genetic variability was evaluated using pulsed-field gel electrophoresis (PFGE) and AMR testing was performed. Prevalence of Campylobacter spp. ranged from 11.1% in the enrichable cages to 19.7% in the conventional systems. A greater prevalence of Campylobacter was found in the fecal swab samples from free-range birds compared with those of birds housed in the more intensive housing systems (p > 0.05). Overall, 72 isolates were confirmed as Campylobacter spp. by PCR. More than 90% of the isolates (n = 66) were identified as Campylobacter jejuni, followed by Campylobacter coli (n = 6). C. jejuni isolates displayed high levels of resistance to tetracycline (67%). Genetic variability of Campylobacter was high, with more than 20 PFGE patterns identified. Pattern "a" comprised 42% of isolates from all housing systems and was also the most persistent. This study suggests that housing systems of laying hens used for commercial shell egg production may impact the rate of Campylobacter shedding by layers. Isolation rates and tetracycline resistance levels of this pathogen are still of concern, emphasizing the need for well-implemented biosecurity measures on the farm.

Effects of litter floor access and inclusion of experienced hens in aviary housing on floor eggs, litter condition, air quality, and hen welfare

With different cage-free (CF) housing styles and management schemes, retailers have developed their own CF criteria. One highly debated aspect is if hens may be kept inside the system for part of the day-during the first few hours after lights-on. Research is lacking regarding the impacts of such a practice on hen welfare, incidence of eggs laid on the litter floor, litter condition, and air quality. This 14-mo field study was conducted to help assess such impacts. Hens (Dekalb White) in an aviary house (50,000-hen nominal capacity) were allowed to have full litter access (FLA) vs. part-time litter access (PLA) from 10:50 am to 9:00 pm, coupled with the absence or presence of experienced hens (1.5% of the population), hence a 2 × 2 factorial arrangement. The measured variables included a) incidence of floor eggs, b) percentage of birds remaining on litter floor at night, c) mortality, d) body weight (BW) and BW uniformity, e) litter condition (depth, moisture content, texture, amount removed, and bacteria concentration), f) environmental conditions, and g) welfare conditions (10 variables). Compared to FLA, PLA had a significantly lower incidence of floor eggs (1.4 ± 0.1 vs. 12.6 ± 1.1 eggs per hen housed as of 76 weeks of age (WOA), i.e., approximately 89% reduction), less manure deposition on the floor (0.53 ± 0.02 vs. 1.05 ± 0.04 kg/100 hens/d, dry basis, i.e., approximately 50% reduction), and lower ammonia concentrations due to drier litter (averaging 22% lower). Inclusion of 1.5% experienced hens in the young flock did not show benefit of reducing the incidence of floor eggs (P = 0.48). The percentage of hens remaining on the floor at night was low (< 0.01%) in all cases from 24 WOA onward. No differences were detected between FLA and PLA in hen welfare conditions, mortality, BW, BW uniformity, bacteria concentration in the litter, air temperature, or relative humidity.

Health Risk Assessment for Human Exposure to Trace Metals and Arsenic via Consumption of Hen Egg Collected from Largest Poultry Industry in Iran

The relative contribution of foodstuffs to intake of heavy metal is still equivocal, and thus, available data are rare. Here, the concentration of ten heavy metals and arsenic were measured in the content of hen egg from five strains of commercial laying hens to evaluate contamination level and potential health risk among local and international consumers in Iran. The estimated daily intake (EDI) of all heavy metals was significantly lower than the provisional tolerable daily intake (PTDI) and respective tolerable daily intake (TDI). The non-carcinogenic and carcinogenic risk values for eating eggs were in the safe range for all consumers, indicating that the no health risk for consumers due to the daily intake of either arsenic or heavy metals. Therefore, intake of heavy metal exposure through the consumption of commercial egg product in Iran is completely safe for both national and international consumers.

Managing Marek's disease in the egg industry

The industrialization of farming has had an enormous impact. To most, this impact is viewed solely in the context of productivity, but the denser living conditions and shorter rearing periods of industrial livestock farms provide pathogens with an ideal opportunity to spread and evolve. For example, the industrialization of poultry farms drove the Marek's disease virus (MDV) to evolve from a mild paralytic syndrome to a highly contagious, globally prevalent, deadly disease. Fortunately, the economic catastrophe that would occur from MDV evolution is prevented through the widespread use of live imperfect vaccines that limit disease symptoms, but fail to prevent transmission. Unfortunately, the continued rollout of such imperfect vaccines is steering MDV evolution towards even greater virulence, and the ability to evade vaccine protection. Thus, there is a need to investigate alternative economically viable control measures for their ability to inhibit MDV spread and evolution. In what follows we examine the economic viability of standard husbandry practices for their ability to inhibit the spread of both virulent MDV and very virulent MDV throughout an industrialized egg farm. To do this, we parameterize a MDV transmission model and calculate the loss in egg production due to MDV. We find that MDV strain and the cohort duration have the greatest influence on both disease burden and egg production. Additionally, our findings show that for long cohort durations, conventional cages result in the least per capita loss in egg production due to MDV infection, while Aviary systems perform best over shorter cohort durations. Finally, we find that the least per capita loss in egg production for flocks infected with the more virulent MDV strains occurs when cohort durations are sufficiently short. These results highlight the important decisions that managers will face when implementing new hen husbandry practices.

Salmonella control in poultry flocks and its public health impact

An increase in confirmed human salmonellosis cases in the EU after 2014 triggered investigation of contributory factors and control options in poultry production. Reconsideration of the five current target serovars for breeding hens showed that there is justification for retaining Salmonella Enteritidis, Salmonella Typhimurium (including monophasic variants) and Salmonella Infantis, while Salmonella Virchow and Salmonella Hadar could be replaced by Salmonella Kentucky and either Salmonella Heidelberg, Salmonella Thompson or a variable serovar in national prevalence targets. However, a target that incorporates all serovars is expected to be more effective as the most relevant serovars in breeding flocks vary between Member State (MS) and over time. Achievement of a 1% target for the current target serovars in laying hen flocks is estimated to be reduced by 254,400 CrI95[98,540; 602,700] compared to the situation in 2016. This translates to a reduction of 53.4% CrI95[39.1; 65.7] considering the layer-associated human salmonellosis true cases and 6.2% considering the overall human salmonellosis true cases in the 23 MSs included in attribution modelling. A review of risk factors for Salmonella in laying hens revealed that overall evidence points to a lower occurrence in non-cage compared to cage systems. A conclusion on the effect of outdoor access or impact of the shift from conventional to enriched cages could not be reached. A similar review for broiler chickens concluded that the evidence that outdoor access affects the occurrence of Salmonella is inconclusive. There is conclusive evidence that an increased stocking density, larger farms and stress result in increased occurrence, persistence and spread of Salmonella in laying hen flocks. Based on scientific evidence, an impact of Salmonella control programmes, apart from general hygiene procedures, on the prevalence of Campylobacter in broiler flocks at the holding and on broiler meat at the end of the slaughter process is not expected.

Heavy Metal (Cd and Pb) and Aflatoxin Contamination in Tissues and Eggs from Free Grazing Ducks and Their Environment in Central Thailand

The cross-sectional study of heavy metals and aflatoxins was conducted by studying duck egg, blood, liver, feed, and water samples from 11 free grazing farms. The duck feed, soil, and rice samples were lower than the standard limit for aflatoxins at 20 ng g^-1. The highest levels of aflatoxin were detected in the liver, intestine, and egg yolk; these were 3.04, 1.73, and 4.56 ng g^-1 respectively, while the average levels were 1.6 ± 0.73, 1.31 ± 0.23, and 1.87 ± 0.99 ng g^-1, respectively. Interestingly, aflatoxin was not detected in any of the egg white albumin samples (90/90 samples), whereas aflatoxin contamination was predominantly found in the yolk. Additionally, the means and standard deviations of Pb and Cd found in the duck eggs were 118.61 ± 22.25 and 13.84 ± 9.06 ng g^-1 respectively. The maximum levels of Pb and Cd in eggs were 134.34 and 29.72 ng g^-1, respectively. Moreover, Pb contamination occurred in the duck liver tissue in 93.61% (88/94) of the samples, whereas Cd contamination was found in 100% (100/100). The maximum levels of Pb and Cd in the duck liver tissues were 606.16 and 22,946.20 ng g^-1, which was higher than those in the eggs. Pb contamination in the water from rice paddy fields after grazing was significantly higher than that in water samples taken before grazing. This is the first report of Pb and Cd contamination in blood, egg, and liver samples of free grazing ducks in Thailand.

Comparison of zinc, lead, cadmium, cobalt, manganese, iron, chromium and copper in duck eggs from three duck farm systems in Central and Western, Thailand

This was a comparative study of the heavy metal levels (Zn, Pb, Cd, Co, Mn, Fe, Cr and Cu) in eggs from free grazing duck, small-scale, and large-scale farms in central and western regions of Thailand. A questionnaire was used to gather demographic data for the analysis of heavy metal contamination in feed, drinking water and wastewater. The correlation between the amounts of heavy metal contamination in eggs was studied against the heavy metals found in feed, drinking water and wastewater. The levels of Pb, Cd, Cr and Cu in eggs from large-scale farms were significantly higher than small farms and free grazing farms at P < 0.001. Zn in eggs from free grazing farms was higher than in the small farms and large-scale farms sampled. The contamination of Pb in eggs from all types of farms exceeded the standard limits of ACFS 6703-2005. The average levels of Pb in the eggs from small-scale farms correlated significantly with the level of Pb found in the feed at P < 0.05, while the average levels of Pb in eggs from free grazing duck farms correlated significantly with the levels of Pb found in the drinking water at P < 0.05. Additionally, the average level of Cu in duck egg from large-scale farms correlated significantly with the level of Cu found in the feeds at P < 0.001. Furthermore, from a calculation of the provisional tolerable daily intake (WHO-FAO) of heavy metals in this study, it was concluded that consumers face health risks from Cd contamination. Thus, heavy metal contamination, especially Pb and Cd in duck egg, must be of concern due to the health risks and the route of crucial heavy metals contamination should be elucidated and long - term monitoring of heavy metals posing health effects in farm systems should be carried out.

Impact of Different Rearing Systems and Age on Bovans White Layer’s Performance, Egg Quality Traits and Synthesis of Heat Shock Protein 70 kDa

This study was conducted to investigate the performance of laying hens and to determine possible age-related changes on external and internal quality traits of their eggs and synthesis of heat shock protein 70 kDa (HSP70) in the conventional cage and organic rearing systems. For this purpose, 4 different Bovans White hybrid flocks of the same age were monitored in each of these two systems for 52 weeks. While a total of 360 eggs were examined to determine the effects of rearing system and age (30 and 60 weeks) on egg quality traits, 48 liver tissue samples were examined for the analysis of HSP70. Egg production (hen-day) and dirty egg ratio were higher in the organic rearing system (P<0.05). The age at 50% yield, the age at peak of lay, and peak production rate were calculated as 156, 218.75 days and 95.98% in the conventional system, and 155.75, 201.50 days, and 96.56% in the organic system, respectively (P>0.05). While egg weight, albumen weight, yolk weight, shell weight, shape index, and yolk colour were higher in the organic system, the crude ash ratio of eggshell and shell ratio were higher in the conventional system (P<0.05). It was also found that the egg weight, albumen weight, yolk weight, shell weight, and the percentage of yolk were higher at 60 weeks of age (P<0.001). The percentage of shell and albumen, shape index, and yolk colour were higher at 30 weeks of age (P<0.001). The interactions between rearing system and age were statistically significant in terms of shell thickness, shape index, crude ash ratio, and yolk colour (P<0.001). Stress protein (HSP70) level was affected only by the rearing system and was higher in the organic system (P<0.001). As a result, the organic system can be considered as advantageous in terms of egg production and quality traits and the eggs of young hens exhibited better properties. The high level of HSP70 in the organic system could indicate that hens were affected by the environmental conditions at higher rates and/or the hens reared in the organic system had a stronger antioxidant defence system.

Characterisation of the Mycobiota on the Shell Surface of Table Eggs Acquired from Different Egg-Laying Hen Breeding Systems

Microbial safety is an important factor contributing to the egg quality. During egg acquisition, there is significant risk of contamination of the eggshell surface with microscopic fungi. Mycelial hyphae may grow on the eggshell surface and penetrate into the egg content. However, there is no information on the populations of microscopic fungi on the eggshell surface and, consequently, on possible production of mycotoxins. Therefore, the aim of the study was to identify the species of microscopic fungi present on the eggshell surface acquired from different breeding systems and to measure the number of selected mycotoxins. The qualitative analysis resulted in the identification of 41 isolates on the surface of eggs. There were 7 isolates from the organic production system, 11 from the free-range production system, 14 from the deep litter indoor housing system and 9 from the cage farming production system. The research proved that the diversification in the population of mycobiota on the eggshells depended on the egg-laying hen breeding system. The microscopic fungi isolated from the eggshells included toxigenic and pathogenic species such as Fusarium culmorum and F. equiseti. As the egg storage time increased, fungi, including the pathogenic species, penetrated through the eggshells. In consequence, mycotoxins were identified in the egg whites. Type-A and type-B trichothecenes were found in the eggshell samples containing F. culmorum.