Problem statement: Poultry industry usually exposing birds to a variety of actions and stressors includs fasting for gastrointestinal emptying before transportation and where birds are often exposed to high environmental temperature during the summer months. These environmental stressors may have influences on bird performance and susceptibility to pathogens such as Salmonella enteritidis by altering the intestinal micrbiota and changes in the gut integrity. Approach: This research was conducted to show that acute stressors in the poultry production can induce changes in the normal intestinal microbiota and epithelium structure and execratory functions, which may cause an increase in the opportunities of attachment of Salmonella enteritidis. Results: Experiments were conducted to determine the influence of 24 h feed withdrawal with 24 h exposure to high temperature (30°C) on intestinal characteristics of broilers. Attachment of Salmonella enteritidis to ileal tissue was determined using an in vitro ileal loop assay. Changes in commensally intestinal microbial populations were determined using gel electrophoresis and alterations in ileal morphology were determined histologically. The results showed that attachment of Salmonella enteritidis to ileal tissues increased by 1.5 logs (9.05 log 10 Vs 7.59 log 10 Salmonella enteritidis/g of ileal tissue; p = 0.0006) in broilers fasted for 24 h also, ileal tissues from birds subjected to 30°C for 24 h had increased the attachment of Salmonella enteritidis (8.77 log 10 Vs 8.50 log 10 Salmonella enteritidis/g of ileum; p = 0.01) compared with birds held at 23°C. Exposure to 30°C for 24 h also altered the microbial structure in the ileum and cecum. Where subjecting birds to 30°C for 24 h reduced the crypt depth (6.0 Vs 7.8 µm, respectively; p = 0.002), but it had no effect on villus height or villus: Crypt ratio. Conclusion: The findings of the experiment explained the mechanisms by which stressors alters the normal intestinal characterization and induces susceptibility to enteric infection. Future work should focus on the use of prophylactic measures to reduce the stress conditions causing alteration of the intestinal microbiota and changes in gut integrity like considering the probiotic organisms the offer a promising solution for reducing pathogen colonization when fed orally.

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Problem statement: Poultry industry is intensive and consistently applies an all-in, all-out system with the aim of minimizing infection pressure and targeting specific pathogens like Salmonella which remains one of the leading causes of food-borne illness, many questions regarding the introduction and persistence in animal production still remain. Therefore disinfection during production break is a routine part of the biosecurity programs of poultry houses. The correct usage of disinfectants is an important key of a successful biosecurity program in poultry farms and in-turn the role of the scientist was to evaluate the efficacy of these disinfection programs. Approach: In this study five commercial disinfectants [Green work (green non anionic surfactant), Sanidate RTU (hydrogen peroxide compound), Hi-yeild^®consan 20^® (phenolic compound), Tektrol_® (quaternary ammonium compound) and Kreso_®D (phenolic compound)] were evaluated against Salmonella typhimurium in two different experimental conditions. In Experiment I, S. typhimurium was inoculated into fresh poultry litter (aluminum trays L: 30 cm x W: 25 cm x D: 6 cm filled with wood shavings) by inoculums size of ~107 CFU mL^-1 and then mixed with 100 g of fresh poultry droppings. Sample sizes of 3 g were obtained daily for the bacterial counts. Green work achieved100% killing of S. typhimurium by day 7 (p≤0.0001); Sanidate RTU achieved100% killing by day 6 (p≤0.001); Hi-yield^® Consan^®, Tektrol_® and Kreso_® D achieved100% killing by day 5 (p≤0.001). Disinfectants were also compared to each other in their efficacy each day. At day 1, Green work was inferior to all other disinfectants at (p≤0.05). On day 2, Kreso_® D was significantly superior to Tektrol_®, Hi-yield^® Consan^®, Sanidate RTU and Green work at p≤0.01, p≤0.01, p≤0.01, p≤0.005; respectively. At day 4 Kreso_® D was significantly superior to Hi-yield^® Consan^® at p≤0.01, Tektrol_® was also significantly superior to Green work at p≤0.01. In experiment II; MIC use-dilution test was used to evaluate the five disinfectants against S. typhimurium (~107CFU mL^-1) in the absence of organic matter. Results: Hourly samples were collected for the bacterial counts. Maximum efficacy (100% killing efficacy against S. typhimurium) was achieved for Green Work after 16 h (p≤0.0001), with Sanidate RTU after 8 h (p≤0.0001), with Hi-yield^® Consan^® and Kreso_® D after 2 h at (p≤0.0001) and with Tektrol_® after 4 h (p≤0.0001). In presence of organic matter Green work and Sanidate RTUachieved 100% killing efficacy against S. typhimurium after 16 h (p≤0.0001), Hi-yield^® Consan^® and Kreso_® D after 2 h at (p≤0.0001);...

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