In modern poultry production systems, environmental stressors may influence bird performance and susceptibility to pathogens such as Salmonella Enteritidis. Experiments were conducted to determine the influence of 24-h feed withdrawal and 24-h exposure to high temperature (30 degrees C) on intestinal characteristics of broilers. Attachment of Salmonella Enteritidis to ileal tissue was determined using an in vitro ileal loop assay. Changes in commensal intestinal microbial populations were determined using denaturing gradient gel electrophoresis, and alterations in ileal morphology were determined histologically. Ex vivo attachment of Salmonella Enteritidis to ileal tissues increased by 1.5 logs (9.05 log10 vs. 7.59 log (10) Salmonella Enteritidis/g of ileal tissue; P = 0.0006) in broilers fasted for 24 h. Similarly, ileal tissues from birds subjected to 30 degrees C for 24 h had increased ex vivo 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 degrees C. Exposure to 30 degrees C for 24 h also altered microbial community structure in the ileum and cecum. Subjecting birds to 30 degrees C for 24 h reduced crypt depth (6.0 vs. 7.8 microm, respectively; P = 0.002), but had no effect on villus height or villus:crypt ratio. This research shows that acute stressors in poultry production systems can cause changes in the normal intestinal microbiota and epithelial structure, which may lead to increased attachment of Salmonella Enteritidis.

In an effort to reduce carcass contamination and consequent reprocessing, market-age broilers are often subjected to feed withdrawal (FW) before processing to reduce intestinal content and intestinal ruptures during processing. However, little is known regarding the effects of FW on mucus content and intestinal morphology. Therefore, 2 experiments were conducted to determine the effects of FW on intestinal characteristics. Male broilers were raised in floor pens on standard industry diets to 42 and 39 d of age for Experiments (Exp.) 1 and 2, respectively. In Exp. 1, feed was removed 24, 12, 8, and 0 h before sampling, respectively (n = 5 birds/time). Birds remained on litter with access to water for the first 4-h of the FW period and were then placed in crates. Body weights, left pectoralis major weights, and distal ileal and jejunal segments were collected for determination of morphological characteristics. For Exp. 2, birds (n = 8 birds/time) were subjected to 0, 12, and 24 h of FW. Birds were injected with 5-bromo-2'-deoxyuridine and thymidine at 24 and 21 h, respectively, before sampling to determine epithelial cell migration rates. One-centimeter distal ileal segments were collected for mucus quantification at 0, 12, and 24 h. In Exp. 1, ileal villi heights were unaffected by FW, but villus width and crypt depth decreased with increasing FW time (P < or = 0.05). Jejunal villus height increased as FW progressed. Jejunal crypt depths increased until 12 h of FW and then declined at 24 h. Mucus content decreased linearly and was reduced by 46% from 0 to 24 h FW (P < 0.05). The intestinal morphology alterations and the depletion of intestinal mucus that occur during a short-term FW may reduce the integrity of the intestine.

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Copper sulfate is often added to broiler and laying hen diets at prophylactic dosages due to its antimicrobial and growth promoting effects despite reduced P digestibility, whereas P use from other Cu sources is unknown. Therefore, male broiler chicks were fed diets containing 0 or 250 ppm Cu from Cu sulfate (Cu SUL), Cu citrate (Cu CIT), Cu lysinate (Cu LYS), or CuCl from 9 to 22 d of age (8 cages/diet, 6 birds/cage) to determine the effect of each Cu source on performance characteristics, bone mineralization, and P retention. Body weight gain was not different among treatments (P > 0.05). Supplementation with 250 ppm Cu from Cu LYS resulted in chicks having greater toe and tibia ash weights as compared with chicks fed Cu SUL (P < or = 0.05) but was not significantly different from those of birds fed Cu CL, Cu CIT, and 0 ppm Cu diets. Supplementation with Cu LYS resulted in birds with greater toe ash percentage as compared with birds fed Cu CIT, Cu SUL, and the 0 ppm Cu diets (P < or = 0.05) but was not significantly different than those of birds fed the CuCl diet. Birds fed the Cu LYS diet had greater tibia ash percentage as compared with birds fed Cu SUL and 0 ppm Cu diets (P < or = 0.05) but were not significantly different than birds fed the Cu CL or Cu CIT diet. Supplementation with 250 ppm Cu SUL or Cu CIT reduced apparent P retention by 0.029 and 0.053 percentage-units of the diet, respectively (P < or = 0.05) as compared with the 0 ppm diet; whereas the apparent P retention when 250 ppm Cu LYS or Cu CL was fed was not different from the 0 ppm Cu diet (P > 0.05). Feeding of different Cu sources in a subsequent experiment had no influence on P retention in laying hens (P > 0.05). In conclusion, supplementation with 250 ppm Cu from Cu CIT or Cu SUL resulted in decreased apparent P retention. Supplementation with 250 ppm Cu CL or Cu LYS, however, improved apparent P retentions as compared with Cu CIT or Cu SUL.

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