Hearing conservation in the primary aluminium industry.

BACKGROUND: Noise-induced hearing loss has been an intractable problem for heavy industry. AIMS: To report our experience in reducing the incidence of age-corrected confirmed 10 dB hearing shifts (averaged over 2, 3 and 4 kHz) in employees in the primary aluminium industry in Australia over the period 2006-13. METHODS: We analysed annual audiometric data to determine the number of permanent hearing shifts that occurred in employees in two bauxite mines, three alumina refineries and two aluminium smelters. Annual hearing shift rates were calculated based on the number of employees tested per year. Hearing conservation initiatives undertaken during the study period are described. An assessment of similar exposure group noise exposures was also undertaken to determine the magnitude of noise exposure reduction during the study period. RESULTS: Across all operations, hearing shift rates declined from 5.5% per year in 2006 to 1.3% per year in 2013 (P < 0.001). The decline in shift rates was greater in mines and refineries, where baseline shift rates were higher, than in smelter workers. Modest reductions in noise exposure occurred during the study period. CONCLUSIONS: We observed a substantial decline in hearing shift rates during the study period. We describe the hearing conservation initiatives that were collectively associated with this decline. We suspect these initiatives could be deployed relatively easily and at modest cost in other industries with noise-exposed employees.

Environmental augmentation with bacteriophage prevents colibacillosis in broiler chickens.

Bacteriophages are viruses that kill bacteria. They are plentiful in nature; are safe, having no known activity to human or animal cells; and are an attractive alternative to antibiotics. The objectives of this research were to establish an experimental model of colibacillosis induced by indirect exposure to Escherichia coli and to determine if bacteriophage could protect the birds from developing colibacillosis. In study 1 there were 6 treatments with 2 replicate pens of 25 birds. The treatments were control warm brooded; control cold stressed; litter inoculated with E. coli, warm brooded; litter inoculated with E. coli, cold stressed; seeder birds (5 per pen) challenged with E. coli, warm brooded; and seeder birds (5 per pen), cold stressed. The study concluded when the birds were 3 wk of age. Body weights at 1, 2, and 3 wk of age were significantly decreased (P ≤ 0.05) by cold stress, decreased at 1 and 2 wk of age by both the litter and seeder bird treatments compared with the control treatment and by the seeder bird treatment at 3 wk of age. Study 2 consisted of 8 treatments with 2 replicate pens of 20 birds per treatment. The treatments were control, warm brooded; control, cold stressed; litter inoculated with E. coli, cold stressed; and seeder birds (5/pen) challenged with E. coli, cold stressed with and without bacteriophage treatment. In the bacteriophage treatments the bacteriophages were sprayed on the litter. The study was concluded at 3 wk of age. Body weights at 1 wk of age were significantly (P ≤ 0.05) decreased from the control treatment by the seeder bird treatment and were significantly (P ≤ 0.05) higher in all the bacteriophage treatments compared with their matched untreated treatments, except in the control cold stressed treatment. Mortality was significantly (P ≤ 0.05) decreased by bacteriophage in the litter challenged treatment. These data suggest that augmentation of the environment with bacteriophage is a practical and efficacious way to prevent colibacillosis in broiler chickens.

Method of administration affects the ability of bacteriophage to prevent colibacillosis in 1-day-old broiler chickens.

Bacteriophages are viruses that kill bacteria. They are plentiful in nature with no known activity in human or animal cells, making them an attractive alternative to antibiotics. The objective of this research was to determine if a coarse or a fine spray of bacteriophage would prevent colibacillosis induced by an intratracheal (IT) challenge with Escherichia coli. Two studies were conducted with 6 treatments: untreated control, birds treated with a spray administration of bacteriophage and not challenged, birds administered bacteriophage IT and not challenged, birds not treated and challenged IT with E. coli, birds sprayed with bacteriophage and IT challenged with E. coli, and birds administered bacteriophage IT and challenged IT with E. coli. There were 3 replicate pens of 10 birds per pen, per treatment, and all treatments were administered at 1 d of age. Study 1 was concluded when the birds were 19 d of age, and study 2 was concluded when the birds were 21 d of age. In both studies, neither a coarse nor a fine spray protected the birds from an IT E. coli challenge; however, when bacteriophage was administered IT there was complete protection. This research demonstrates the necessity for the administration of bacteriophage therapeutics to deliver high bacteriophage titers to the site of a bacterial infection.

Use of plant-derived antimicrobials for improving the safety of poultry products.

Salmonella Enteritidis and Campylobacter jejuni are the 2 major foodborne pathogens transmitted through poultry products. Chickens are the reservoir hosts of these pathogens, with their intestinal colonization being the most significant factor causing contamination of meat and eggs. Effective preslaughter strategies for reducing the colonization of birds with these pathogens are critical to improve the microbiological safety of poultry products. An antimicrobial treatment that can be applied through feed represents the most practical and economically viable method for adoption on farms. Additionally, a natural and safe antimicrobial will be better accepted by producers without concerns for toxicity. This symposium talk discussed the potential use of plant-derived, GRAS (generally recognized as safe)-status molecules, caprylic acid, trans-cinnamaldehyde, eugenol, carvacrol, and thymol as feed supplements for reducing cecal populations of Salmonella Enteritidis and C. jejuni in chickens. Additionally, the effect of plant molecules on Salmonella virulence genes critical for cecal colonization in chickens was also discussed.

Effect of trans-cinnamaldehyde nanoemulsion wash on chicken embryo development in fertilized eggs.

Cleanliness of eggs is critical in successful hatching egg operations. The objective of this study was to investigate the effect of trans-cinnamaldehyde nanoemulsion (TCNE) wash treatments, as a sanitation strategy, on embryonic development in fertilized eggs. Trans-cinnamaldehyde is a generally recognized as safe status phytochemical obtained from cinnamon bark. TCNE were prepared with emulsifiers Tween 80 (Tw.80) or gum Arabic and lecithin (GAL) by sonication. Day-old fertilized eggs were subjected to TCNE wash treatments at 34°C for 5 min, followed by 18 d of incubation at 37.7°C. Washing of fertilized eggs with TCNE-Tw.80 or GAL at 0.48% concentration did not significantly alter the egg weight at d 18 of incubation, as compared to baseline and control (P > 0.05). The egg weight loss (calculated as percentage) did not differ significantly between eggs subjected to nanoemulsion wash treatments and control eggs (P > 0.05). In case of embryo fertility and mortality, for baseline and control, ∼ 95% fertility rate was achieved, with combined early and midterm mortality at 16%. Likewise, TCNE-Tw.80 or TCNE-GAL resulted in 95% fertility (P > 0.05), with 11% and 17% combined early and midterm mortality, respectively. Furthermore, TCNE wash treatments did not differ significantly in yolk sac and embryo weight (as compared to control) and did not affect the length of the d 18 embryo (P > 0.05). Moreover, TCNE wash treatments did not alter tibia weight and length (P > 0.05). Results suggest that TCNE could potentially be used as a natural antimicrobial for fertilized egg sanitation. Further studies in industry settings are warranted.

Trans-cinnamaldehyde nanoemulsion wash inactivates Salmonella Enteritidis on shelled eggs without affecting egg color.

Salmonella Enteritidis is a major foodborne pathogen that causes enteric illnesses in humans, primarily through the consumption of contaminated poultry meat and eggs. Despite implementation of traditional disinfection approaches to reduce S. Enteritidis contamination, egg-borne outbreaks continue to occur, raising public health concerns and adversely affecting the popularity and profitability for the poultry industry. Generally Recognized as Safe (GRAS) status phytochemicals such as Trans-cinnamaldehyde (TC) have previously shown to exhibit anti-Salmonella efficacy, however, the low solubility of TC is a major hurdle in its adoption as an egg wash treatment. Therefore, the present study investigated the efficacy of Trans-cinnamaldehyde nanoemulsions (TCNE) prepared with emulsifiers Tween 80 (Tw.80) or Gum Arabic and lecithin (GAL) as dip treatments, at 34°C, for reducing S. Enteritidis on shelled eggs in presence or absence of 5% chicken litter. In addition, the efficacy of TCNE dip treatments in reducing trans-shell migration of S. Enteritidis across shell barrier was investigated. The effect of wash treatments on shell color were evaluated on d 0, 1, 7, and 14 of refrigerated storage. TCNE-Tw.80 or GAL treatments (0.06, 0.12, 0.24, 0.48%) were effective in inactivating S. Enteritidis by at least 2 to 2.5 log cfu/egg as early as 1 min of washing time (P < 0.05). In presence of organic matter, nanoemulsions (0.48%) reduced S. Enteritidis counts by ∼ 2 to 2.5 log cfu/egg as early as 1 min, (P < 0.05). Nanoemulsion wash also inhibited trans-shell migration of S. Enteritidis, as compared to control (P < 0.05). The nanoemulsion wash treatments did not affect shell color (P > 0.05). Results suggest that TCNE could potentially be used as an antimicrobial wash to reduce S. Enteritidis on shelled eggs, although further studies investigating the effect of TCNE wash treatments on organoleptic properties of eggs are necessary.

Caprylic acid reduces Salmonella Enteritidis populations in various segments of digestive tract and internal organs of 3- and 6-week-old broiler chickens, therapeutically.

We investigated the efficacy of feed supplemented with caprylic acid (CA), a natural, 8-carbon fatty acid for reducing Salmonella enterica serovar Enteritidis colonization in commercial broiler chickens. In separate 3- and 6-wk trials, 1-d-old straight-run broiler chicks (n = 70 birds/trial) were assigned to a control group (challenged with Salmonella Enteritidis, no CA) and 2 replicates of 0.7 and 1% CA (n = 14 birds/group). Water and feed were provided ad libitum. On d 1, birds were tested for any inherent Salmonella (n = 2 birds/group). For the 3-wk trial, on d 5, birds were challenged with 8 log(10) cfu of Salmonella Enteritidis of a 4-strain mixture by crop gavage, and after 5 d postchallenge, birds (n = 2 birds/group) were euthanized to ensure Salmonella Enteritidis colonization. Caprylic acid was supplemented the last 5 d before tissue collection (n = 10 birds/group). For the 6-wk trial, on d 25, birds were challenged and confirmed for Salmonella Enteritidis colonization. The birds (n = 10 birds/group) were euthanized for tissue samples after CA supplementation for the last 5 d. Caprylic acid at 0.7 or 1% decreased Salmonella Enteritidis populations in cecum, small intestine, cloaca, liver, and spleen in both 3- and 6-wk trials. Body weight of birds did not differ between the groups (P ≥ 0.05). Further, to elucidate a potential antibacterial mechanism of action of CA, we investigated if CA could reduce Salmonella Enteritidis invasion of an avian epithelial cell line and expression of invasion genes hilA and hilD. The cell invasion study revealed that CA reduced invasive abilities of all Salmonella Enteritidis strains by ~80% (P < 0.05). Gene expression studies indicated that CA downregulated (P < 0.001) Salmonella invasion genes hilA and hilD. These results suggest that supplementation of CA through feed could reduce Salmonella Enteritidis colonization in broiler chicken and potentially reduces the pathogen's ability to invade intestinal epithelial cells by downregulating key invasion genes, hilA and hilD.

Water administration of the medium-chain fatty acid caprylic acid produced variable efficacy against enteric Campylobacter colonization in broilers.

Campylobacter is one of the most common causes of foodborne illness, and poultry are considered a primary source of Campylobacter infections. Caprylic acid, an 8-carbon fatty acid, has been shown in previous studies to reduce enteric cecal Campylobacter concentrations in poultry when administered in the feed. For greater ease of application for producers, a water-soluble form of caprylic acid, sodium octanoate, was evaluated for efficacy against enteric Campylobacter. The first trial consisted of 70 birds in 7 groups (n = 10 chicks/group): an untreated control and 6 other groups that were challenged with Campylobacter at d 3 and that received 0, 0.175, 0.35, 0.7, 1.4, or 2.8% water-soluble caprylic acid in water 3 d before necropsy at d 14. The second trial consisted of 80 birds in 8 groups (n = 10 chicks/group): an untreated negative control and 7 other groups, all of which were challenged with Campylobacter at d 3 and received 0, 0.044, 0.088, 0.175, 0.35, 0.7, or 1.4% water-soluble caprylic acid for 3 d before necropsy at d 14. In trial 1, only the 0.175% dose caused a reduction in cecal Campylobacter counts in comparison with the positive control (approximately a 3-log reduction). In trial 2, no treatment reduced Campylobacter counts compared with the positive control. Unlike the efficacy of caprylic acid in feed, treatment with caprylic acid in water had an inconsistent effect on intestinal Campylobacter counts.

Immune interference of bacteriophage efficacy when treating colibacillosis in poultry.

A study was conducted to determine if prior exposure with bacteriophage would limit the ability of the same bacteriophage to treat colibacillosis. There were 5 treatments with 3 replicate pens of 20 birds per pen. The treatments consisted of 1) control, 2) birds treated with bacteriophage at 10 and 17 d of age, 3) birds challenged with Escherichia coli at 17 d of age, 4) birds challenged with E. coli and treated with bacteriophage at 17 d of age, and 5) birds treated with bacteriophage at 10 d of age and challenged with E. coli and treated with bacteriophage at 17 d of age. Colibacillosis was induced by injecting 0.1 mL of E. coli into the thoracic airsac containing 1 x 10(6) cfu. The bacteriophage was administered by i.m. injection of 0.1 mL into the thigh, providing a dose of 6.8 x 10(8) pfu. The study was concluded 14 d after E. coli challenge. Mortality in the birds challenged with E. coli and not treated with bacteriophage was 55% (treatment 3), and bacteriophage therapy significantly (P < or = 0.05) reduced mortality to 8% (treatment 4), which was not significantly (P < or = 0.05) different from the 2 non-E. coli-challenged controls (3%, treatment 1, and 2%, treatment 2). However, mortality in the birds administered bacteriophage before challenge with E. coli and treated with bacteriophage (treatment 5) was 33%, which was not significantly different (P < or = 0.05) from the birds that were challenged with E. coli and untreated (55%, treatment 3). A kinetic in vitro assay of bacteriophage activity found that serum from birds pretreated with bacteriophage (treatment 5) inhibited bacteriophage activity. The IgG levels to the bacteriophage in serum from birds pretreated with bacteriophage (treatment 2) were significantly higher at all dilutions compared with control serum (treatment 1). These data demonstrate that prior exposure to bacteriophage will limit bacteriophage therapeutic efficacy and suggests that the reduced efficacy is due to an immune response to bacteriophage.

Bacterial clearance, heterophil function, and hematological parameters of transport-stressed turkey poults supplemented with dietary yeast extract.

Yeast extracts (YE) contain biological response modifiers that may be useful as alternatives to antibiotics for controlling pathogens in poultry production and mitigating the deleterious effects of production stressors. The objective of the present study was to determine the ability of a commercial dietary YE (Alphamune) to modulate the immune response in male turkey poults challenged with Escherichia coli and subjected to transport stress. Alphamune was added to turkey poult diets at 0, 500, or 1,000 g/ton. Poults were challenged by air sac injection with 60 cfu of E. coli at 1 wk of age. At 3 wk of age, these challenged birds were subjected to transport stress and birds were bled and necropsied the following morning. Blood cell numbers and percentages, hematological parameters, and clinical chemistry values were determined. Oxidative burst activity of isolated heterophils was measured using stimulation with phorbol myristate acetate and a 2',7'-dichlorofluorescein diacetate assay. Data were analyzed using GLM and least squares means procedures of the SAS program. The numbers and percentages of heterophils in peripheral blood were increased and their oxidative burst activity was stimulated by YE. The stress challenge dramatically increased oxidative burst and this increase was significantly modulated by YE treatment. Serum levels of calcium, phosphorus, and triglycerides were decreased and uric acid levels, erythrocyte numbers, hemoglobin, and hematocrit were increased by YE supplementation. Bacteria were isolated from the air sac and liver of a lower percentage of birds provided with YE. These results suggest that dietary YE has potential as a nonantibiotic alternative for decreasing bacterial pathogens in turkey production.

Comparisons of sperm storage tubule distribution and number in 4 strains of mature broiler breeders and in turkey hens before and after the onset of photostimulation.

The biological basis of sustained fertility in broiler and turkey hens is their capacity to store sperm in the oviductal sperm storage tubules (SST) located in the uterovaginal junction. The objectives of this study were to determine if the numbers of SST varied between 4 strains of broiler breeders and determine the number of SST in the turkey before (less than 9 d of photostimulation) and after (up to 22 d of photostimulation and laying) photostimulation. No statistical differences were observed in SST numbers in the 4 strains of broilers examined or in turkey hens before and after the onset of egg production. The mean numbers of SST for broilers and turkeys were 4,893 and 30,566, respectively. We conclude that any differences between the fertility of the 4 broiler breeder strains examined cannot be explained by differences in SST numbers. However, differences in the duration of fertility between broilers and turkeys are, in part, related to their respective numbers of number of SST. Furthermore, we conclude that turkey SST are morphologically differentiated and functional before the onset of photostimulation and while the oviduct is morphologically undeveloped.

Carvacrol attenuates Campylobacter jejuni colonization factors and proteome critical for persistence in the chicken gut.

Campylobacter jejuni is a major foodborne pathogen that causes gastroenteritis in humans. Chickens act as the reservoir host for C. jejuni, wherein the pathogen asymptomatically colonizes the ceca leading to contamination of carcasses during slaughter. The major colonization factors in C. jejuni include motility, intestinal epithelial attachment, acid/bile tolerance, and quorum sensing. Reducing the expression of the aforementioned factors could potentially reduce C. jejuni colonization in chickens. This study investigated the efficacy of subinhibitory concentration (SIC; compound concentration not inhibiting bacterial growth) of carvacrol in reducing the expression of C. jejuni colonization factors in vitro. Moreover, the effect of carvacrol on the expression of C. jejuni proteome was investigated using liquid chromatography-tandem mass spectrometry. The motility assay was conducted at 42°C, and the motility zone was measured after 24 h of incubation. For the adhesion assay, monolayers of primary chicken enterocytes (∼105 cells/well) were inoculated with C. jejuni (6 log cfu/well) either in the presence or absence of carvacrol, and the adhered C. jejuni were enumerated after 90 min of incubation at 42°C. The effect of carvacrol on C. jejuni quorum sensing and susceptibility to acid/bile stress was investigated using a bioluminescence assay and an acid-bile survival assay, respectively. The SIC (0.002%) of carvacrol reduced the motility of C. jejuni strains S-8 and NCTC 81-176 by ∼50 and 35%, respectively (P < 0.05). Carvacrol inhibited C. jejuni S-8 and NCTC 81-176 adhesion to chicken enterocytes by ∼0.8 and 1.5 log cfu/mL, respectively (P < 0.05). Moreover, carvacrol reduced autoinducer-2 activity and increased the susceptibility of C. jejuni to acid and bile in both the strains (P < 0.05). Liquid chromatography-tandem mass spectrometry revealed that the SIC of carvacrol reduced the expression of selected C. jejuni colonization proteins critical for motility (methyl-accepting chemotaxis protein), adhesion (GroL), growth and metabolism (AspA, AcnB, Icd, Fba, Ppa, AnsA, Ldh, Eno, PurB-1), and anaerobic respiration (NapB, HydB, SdhA, NrfA) (P < 0.05). Results suggest the mechanisms by which carvacrol could reduce C. jejuni colonization in chickens.

Implementing artificial insemination as an effective tool for ex situ conservation of endangered avian species.

Approximately 503 of the known species of birds are classified as 'endangered' or 'critical'. Captive propagation programs have proven useful in maintaining genetic diversity and restoring wild populations of certain species, including the Peregrine falcon, California condor and Whooping crane. Artificial insemination (AI) has the potential of solving problems inherent to reproductive management of small, closed populations of endangered birds, including dealing with demographic instability, physical and behavioral disabilities, sexual incompatibility, lack of synchrony, and need to maintain gene diversity. In this review, we address the necessary methods and factors that allow AI to be applied effectively to manage rare bird populations. It is clear that semen availability and quality are the greatest limiting factors to implementing consistently successful AI for birds. Behavioral sensitivity to animal handling and the ability to minimize stress in individual birds also are keys to success. Multiple, deep vaginal inseminations can improve fertility, particularly when semen quality is marginal. Laparoscopic methods of semen transfer also have produced fertile eggs. All of these practices leading to successful AI remain dependent on having adequate basic knowledge on female reproductive status, copulatory behavior, endocrine profiles and duration of fertility, especially as related to oviposition. The overall greatest challenge and highest priority is defining these normative traits, which are highly species-specific.

The natural feed additive caprylic acid decreases Campylobacter jejuni colonization in market-aged broiler chickens.

Campylobacter causes human foodborne illness, and epidemiological evidence indicates poultry and poultry products as a significant source of human infection. Decreasing Campylobacter in the poultry intestinal tract would decrease contamination of poultry products. Caprylic acid is a medium-chain fatty acid reported to be effective in killing a variety of bacterial pathogens, including Campylobacter jejuni, but its effect has not been investigated in the control of C. jejuni in preslaughter market-aged poultry already colonized with this bacterium. The objective of this study was to determine the therapeutic effect of caprylic acid on C. jejuni counts in the cecal contents of 42-d-old chickens. Four trials were conducted. In the first 2 trials, day-of-hatch chicks (n = 60 per trial) were assigned to 6 treatment groups (n = 10 birds per treatment group): positive controls (Campylobacter, no caprylic acid), 0.7 or 1.4% of caprylic acid in feed for the last 3 d of the trial with or without a 12-h feed withdrawal. Treatments were similar for trials 3 and 4 except the doses used were 0.35 or 0.7% caprylic acid supplementation for the last 7 d of the trial. On d 42, ceca were collected and Campylobacter counts determined. The supplementation of caprylic acid at 0.35 and 0.7% consistently decreased (P < 0.05) the colonization of C. jejuni in the chicken ceca compared with positive control treatment. When these treatments were evaluated after a 12-h feed withdrawal period, 0.7% caprylic acid decreased Campylobacter colonization in the 3-d treatment supplementation. Body weight and feed consumption did not differ between the caprylic acid and control groups. The results suggest that therapeutic supplementation of caprylic acid in the feed can effectively decrease Campylobacter in market-aged chickens and may be a potential treatment for decreasing pathogen carriage in poultry.

Carvacrol antimicrobial wash treatments reduce Campylobacter jejuni and aerobic bacteria on broiler chicken skin.

Campylobacter jejuni, a major cause of human gastroenteritis worldwide, is often associated with the consumption of contaminated poultry products. With increasing consumer preference to natural and minimally processed foods, interventions utilizing natural antimicrobials for controlling C. jejuni on poultry products are gaining popularity. This study investigated the efficacy of the generally recognized as safe compound carvacrol (CR) as a wash treatment in reducing C. jejuni and aerobic bacteria on chicken skin. Two separate studies, each with 2 trials, were conducted. In the first study, the efficacy of CR suspension (0, 0.25, 0.5, 1, and 2%) was investigated, whereas in the second the efficacy of CR as suspension, emulsion, and nanoemulsion was studied. In both studies, skin samples were inoculated with 50 µL (∼8 log10 cfu/sample) of a cocktail of 4 wild strains of C. jejuni. After 30 min of attachment, samples were washed with the respective treatments for 1 min, drip dried for 2 min, and processed at 0, 8, 24, h post-treatment for enumeration of C. jejuni and aerobic bacterial counts (n = 5/treatment/time point). In addition, the effect of treatments on the color of chicken skin was evaluated. Data were analyzed using PROC MIXED procedure of SAS. In the first study, all the tested doses of CR suspension consistently reduced C. jejuni counts across all time points. The 2% CR suspension wash reduced C. jejuni counts by ∼2.4 to 4 log10 cfu/sample (P < 0.05). In addition, 1% and 2% CR suspensions significantly reduced aerobic counts at all the time points. The results from the second study suggest that anti-Campylobacter efficacy of CR emulsion or nanoemulsion treatments was not improved compared to CR suspension. Several CR suspension treatments were more effective than corresponding emulsion or nanoemulsion treatments. No significant differences were observed in the color of the samples between treatments (P > 0.05). The results suggest that CR could potentially be used as an antimicrobial wash treatment in postharvest poultry.

Pectin or chitosan coating fortified with eugenol reduces Campylobacter jejuni on chicken wingettes and modulates expression of critical survival genes.

Campylobacter jejuni infection in humans is strongly associated with the consumption of contaminated poultry products. With increasing consumer demand for minimally processed and natural product, there is a need for novel intervention strategies for controlling C. jejuni. Antimicrobial coatings are increasingly being used for preventing food contamination due to their efficacy and continuous protection of product. This study investigated the efficacy of pectin and chitosan coating fortified with eugenol to reduce C. jejuni on chicken wingettes. Pectin, chitosan, and eugenol are generally recognized as safe status compounds derived from berries, crustaceans, and cloves respectively. Each wingette was inoculated with a mixture of 4 wild-type strains of C. jejuni (approximately 107 CFU/sample) and randomly assigned to controls, pectin (3%), chitosan (2%), eugenol (0.5, 1, or 2%), or their combinations. Following 1 min of coating, wingettes were air-dried, vacuum sealed, and sampled on 0, 1, 3, 5, and 7 d of refrigerated storage for C. jejuni and aerobic counts (n = 5 wingettes/treatment/d). In addition, the effect of treatments on wingette color and expression of C. jejuni survival/virulence genes was evaluated. All 3 doses of eugenol or chitosan significantly reduced C. jejuni and aerobic bacteria from 0 d through 7 d. Incorporation of 2% eugenol in chitosan improved coating efficiency and reduced C. jejuni counts by approximately 3 Log CFU/sample at the end of 7 d of storage (P < 0.05). Similarly, the antimicrobial efficacy of pectin was improved by 2% eugenol and the coating reduced C. jejuni by approximately 2 Log CFU/sample at 7 d of storage. Chitosan coating with 2% eugenol also showed greater reductions of total aerobic counts as compared to individual treatments of eugenol and chitosan. No significant difference in the color of chicken wingettes was observed between treatments. Exposure of C. jejuni to eugenol, chitosan, or combination significantly modulated select genes encoding for motility, quorum sensing, and stress response. Results demonstrate the potential of pectin or chitosan coating fortified with eugenol as a postharvest intervention against C. jejuni contamination on poultry products.

Therapeutic supplementation of caprylic acid in feed reduces Campylobacter jejuni colonization in broiler chicks.

Poultry colonized with Campylobacter species are a significant source of human food-borne illness. The therapeutic use of the medium chain fatty acid caprylic acid consistently reduced enteric C. jejuni colonization in chicks by 3 to 4 logs in three separate trials. These results support caprylic acid's potential to reduce Campylobacter carriage in poultry.

Bacteriophages for prophylaxis and therapy in cattle, poultry and pigs.

The successful use of virulent (lytic) bacteriophages (phages) in preventing and treating neonatal enterotoxigenic Escherichia coli infections in calves, lambs and pigs has prompted investigation of other applications of phage therapy in food animals. While results have been very variable, some indicate that phage therapy is potentially useful in virulent Salmonella and E. coli infections in chickens, calves and pigs, and in control of the food-borne pathogens Salmonella and Campylobacter jejuni in chickens and E. coli O157:H7 in cattle. However, more rigorous and comprehensive research is required to determine the true potential of phage therapy. Particular challenges include the selection and characterization of phages, practical modes of administration, and development of formulations that maintain the viability of phages for administration. Also, meaningful evaluation of phage therapy will require animal studies that closely represent the intended use, and will include thorough investigation of the emergence and characteristics of phage resistant bacteria. As well, effective use will require understanding the ecology and dynamics of the endemic and therapeutic phages and their interactions with target bacteria in the farm environment. In the event that the potential of phage therapy is realized, adoption will depend on its efficacy and complementarity relative to other interventions. Another potential challenge will be regulatory approval.

Caprylic acid supplemented in feed reduces enteric Campylobacter jejuni colonization in ten-day-old broiler chickens.

Campylobacter is one of the leading causes of human foodborne illness in the United States, and epidemiological evidence indicates that poultry and poultry products are a significant source of human Campylobacter infections. Reducing Campylobacter in the intestinal tract would reduce contamination of poultry products and eggs. Caprylic acid, an 8-carbon medium-chain fatty acid has been shown to be bactericidal against several pathogenic bacteria. It has, however, not been tested in the control of Campylobacter in chickens. Four trials were carried out to evaluate the efficacy of caprylic acid against cecal Campylobacter jejuni colonization in 10-d-old chicks. In the first 2 trials, day-of-hatch chicks (n=40 per trial) were assigned to negative controls (no Campylobacter, no caprylic acid), positive controls (Campylobacter, no caprylic acid), and a low (0.7%) and a high (1.4%) dose of caprylic acid supplemented in regular chick starter feed (n=10 chicks/treatment). Two more trials were carried out to evaluate a wider range of caprylic acid doses on cecal Campylobacter counts, in which day-of-hatch chicks (n=90 per trial) were assigned to 9 treatments: negative controls (no Campylobacter, no caprylic acid) and caprylic acid doses of 0 (positive controls), 0.35, 0.525, 0.7, 0.875, 1.05, 1.225, and 1.4% (n=10 chicks/treatment). Except for the negative controls, chicks were orally gavaged with approximately 1 x 10(6) cfu Campylobacter on d 3. On d 10, cecal contents were collected and Campylobacter concentrations were determined in each trial. In all 4 trials, the 0.7% dose of caprylic acid consistently reduced Campylobacter content counts compared with the positive control. In trials 3 and 4, doses less than 1.05% consistently reduced cecal Campylobacter content in both trials. At the higher doses, caprylic acid reduced feed consumption and body weight, but did not affect feed conversion when compared with the positive controls. These data suggest that low-dose supplementation with caprylic acid in feed may reduce Campylobacter colonization in young chickens.