Necrotic enteritis, caused by Clostridium perfringens type A, is more prevalent in broilers fed wheat or barley diets than in those fed a corn diet. We compared the effects of wheat, barley and corn diets on in vitro proliferation of C. perfringens type A. Bacteria were inoculated into the supernatants delivered from either digested or non-digested barley, wheat and corn diets mixed with thioglycollate medium (1:3). Colony forming units were counted following incubation for 6 h at 40°C. There were no significant differences in clostridial proliferation among non-digested diets. Bacterial proliferation in the digested wheat and barley diets was significantly higher than in the digested corn diet. These findings suggest that the increased incidence of necrotic enteritis in broilers fed barley and wheat diets compared with those fed a corn diet may be due in part to increased clostridial proliferation associated with the wheat and barley diets, or to decreased proliferation associated with the corn diet.

The aim of this study was to examine the main and interaction effects of 3 dietary nutrient densities (low-, medium-, high-density), 2 feed forms (mash, pellet), and 2 lighting programs (20L:4D, 12L:12D) on the walking ability and skeletal quality of broiler chickens raised to a young age (35 d). Forty-eight birds per treatment (nutrient density x feed form x lighting program subclass) were randomly selected (0 d) for assessment of their gait score (GS) and BW at 11, 18, 25, and 32 d. Samples of birds from various GS classifications were selected at 32 d for radiographs and histology of the femur and tibiotarsus. Bone ash (BA) content was evaluated at 35 d from the right tibiotarsus to assess bone quality. Overall, the mean GS values were low (GS <1). An interaction existed between lighting and sex. Males provided with 20L:4D had a higher GS (0.74) than females (0.45), and this score was greater than for broilers provided with 12L:12D (0.34 and 0.26 for males and females, respectively). Feeding mash reduced the GS (0.29) compared with pellet rations (0.62). The GS increased with age, and by 32 d 2.43% of birds had a GS >/=3. Broilers fed mash had a higher BA content (50.6%) than birds fed pellet diets (49.8%), and the 12L:12D value (50.5%) was greater than for 20L:4D (48.9%). Last, males had a lower BA content (49.8%) than females (50.6%). A positive correlation existed between BW and GS based on sex, where BW at 11, 18, and 25 d affected bird mobility at 32 d (r(2) = 0.39, 0.49, and 0.50 for males; r(2) = 0.34, 0.37, and 0.36 for females, respectively). Radiography and histology were unaffected by GS. This study confirmed that a reduced growth rate improved GS but also demonstrated that overall bird mobility was good and the incidence of skeletal disease was low.

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Commercial caged layer flocks in Alberta, Canada, are commonly monitored for Salmonella enterica serovar Enteritidis (SE) and S. enterica serovar Typhimurium (ST) by environmental sampling. In one recent case, a SE strain isolated from the egg conveyor belt was a source of persistent infection for the flock. This study was undertaken to examine Salmonella colonization on egg conveyor belts and to determine whether the rdar morphotype, a conserved physiology associated with aggregation and long-term survival, contributed to persistence. Four woven belts constructed of natural or nonnatural fibers and a 1-piece belt made of vinyl were tested with rdar-positive ST and SE strains and a rdar-negative ST DeltaagfD reference strain. The type of egg belt was the most important factor influencing Salmonella colonization and persistence. The vinyl belt, with the least surface area available for colonization, had the fewest Salmonella remaining after washing and disinfection, whereas the hemp-plastic belt, with the greatest surface area, had the most Salmonella remaining. Real-time gene expression indicated that the rdar morphotype was involved in colonizing the egg belt pieces; however, it was not essential for persistence. In addition, rdar-positive and rdar-negative strains were equally similarly to disinfection on the egg belt pieces. The results indicate that Salmonella can persist on a variety of egg belts by mechanisms other than the rdar morphotype, and that using egg conveyer belts with reduced surface area for bacterial colonization can lessen contamination problems.

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