Effects of Feed Particle Size and Feed Form on Survival of Salmonella typhimurium in the Alimentary Tract and Cecal S. typhimurium Reduction in Growing Broilers
There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.
Abstract
An in vitro experiment and an in vivo experiment were conducted to investigate the
effects of feed particle size (coarse and fine) and feed form (mash and pellet) on
the survival of Salmonella typhimurium (ST) in the alimentary tract, and the reduction
of cecal ST in growing broilers in a 2 x 2 factorial design. All diets in the 2 trials
were corn and soybean meal-based diets that differed only in physical characteristics.
Diets were provided for birds from d 1 to 22 of age. In the in vitro trial, the relative
gizzard weight was lower in birds that were fed the pellet diet (P < 0.01), whereas
the relative weight of the cecum was higher in these birds (P < 0.01). Broilers receiving
the pellet diet had enhanced concentrations of volatile fatty acids in contents from
both the gizzards and the ceca. In addition, there was an increase in gizzard pH (P
< 0.01) with the pellet diet, but a reduction in cecal pH (P < 0.05). Pellet-fed birds
showed a significantly decreased and increased in vitro death rate of ST in the contents
from gizzards (P < 0.01) and ceca (P < 0.05), respectively. A higher in vitro ST death
rate in the gizzard was observed in birds given the coarse mash diet compared with
those given the fine mash diet. In the in vivo experiment, cecal volatile fatty acid
concentrations were increased, whereas cecal pH was decreased significantly (P < 0.05)
when birds were fed the pellet diet compared with the mash diet. Furthermore, cecal
ST concentrations were higher (P < 0.05) in broilers fed the pellet diet than in those
fed the mash diet. Results indicated that the pellet diet increases the incidence
of ST in gizzards and ceca in growing broilers and provide evidence demonstrating
that the gizzard may play a critical role in reducing ST contamination in growing
broilers.