Performance of broilers experimentally inoculated with Salmonella Typhimurium and fed diets with addition of lactulosis

The objective of this experiment was to evaluate the influence of lactulose on performance as well as its ability to prevent colonization by Salmonella Typhimurium in broilers orally inoculated with this pathogen. The design adopted was completely randomized, with 630 one-day-old male chicks distributed into six treatments, with seven replications and 15 birds per experimental unit. The treatments comprised the following procedures: T1 (control group) - no S. Typhimurium inoculation or supply of lactulosis; T2 - only inoculation of S. Typhimurium; T3 - only lactulosis supply; T4 supply of lactulosis and S. Typhimurium inoculation on the first day of life; T5 - supply of lactulosis 48 hours before S. Typhimurium inoculation; and T6 - supply of lactulosis 48 hours after inoculation of S. Typhimurium. Performance variables were evaluated on the seventh, 14th, 21st and 28th days of age; fragments of the duodenum and jejunum were collected and sent to histomorphometric assessment at 14 days of age, and S. Typhimurium excretion was verified in cloacal swabs on the 10th, 24th and 35th days of age. Performance data were analyzed by ANOVA and Tukey's test (5%) and fecal excretion data were assessed by non-parametric chi-square test. Better weight gain and feed conversion were observed in groups fed lactulosis with or without challenge of S. Typhimurium up to 21 days of age. Reduced duodenum villous height was verified on the 14th day in groups challenged with the pathogen. Reduction of S. Typhimurium fecal excretion was verified in broilers fed lactulosis from the first day of life on and 48 hours before receiving S. Typhimurium directly into the crop. Lactulosis increases broiler performance up to one week after its inoculation, influences duodenum villous height and reduces the fecal excretion of Salmonella Typhimurium

Correlation of the Highest-energy Cosmic Rays with the Positions of Nearby Active Galactic Nuclei.

Data collected by the Pierre Auger Observatory provide evidence for anisotropy in the arrival directions of the cosmic rays with the highest energies, which are correlated with the positions of relatively nearby active galactic nuclei (AGN) \cite{science}. The correlation has maximum significance for cosmic rays with energy greater than ~ 6x10^{19}$ eV and AGN at a distance less than ~ 75 Mpc. We have confirmed the anisotropy at a confidence level of more than 99% through a test with parameters specified {\em a priori}, using an independent data set. The observed correlation is compatible with the hypothesis that cosmic rays with the highest energies originate from extra-galactic sources close enough so that their flux is not significantly attenuated by interaction with the cosmic background radiation (the Greisen-Zatsepin-Kuz'min effect). The angular scale of the correlation observed is a few degrees, which suggests a predominantly light composition unless the magnetic fields are very weak outside the thin disk of our galaxy. Our present data do not identify AGN as the sources of cosmic rays unambiguously, and other candidate sources which are distributed as nearby AGN are not ruled out. We discuss the prospect of unequivocal identification of individual sources of the highest-energy cosmic rays within a few years of continued operation of the Pierre Auger Observatory.Comment: 33 pages, 8 figures, submitted to Astropart. phys. Now match the published versio