Effects of Lactobacillus-Based Probiotic on Performance, Gut Microflora, Hematology and Intestinal Morphology in Young Broiler Chickens Challenged with Salmonella Typhimurium

This experiment was conducted to compare the effects of multi-strain probiotic inclusion levels on performance, intestinal morphology, gut microflora and hematological changes in Salmonella typhimurium (ST) infected broiler chickens. A total of 120 day old Ross 308 broiler chickens were distributed into 20 floor pens and reared for 10 days under 5 experimental treatments including a corn-soy basal diet with no probiotic (Control), or 0.5 g (0.05%), 1 g (0.1%), 1.5 g (0.15%) and 2 g (0.2%) probiotic/kg diet. Chickens were infected orally with ST at second day of experiment. Broilers under 0.15% of probiotic had higher body weight gain compared to other treatments. Probiotic supplementation, except at 0.05%, significantly improved feed conversion ratio. The use of 0.1 and 0.15% of probiotic reduced the population of Salmonella in ileum. The lowest heterophil:lymphocyte ratio was observed in 0.15% of probiotic, although 0.1 and 0.2% of probiotic significantly reduced this ratio compared to control group. Adding 0.15% of probiotic to the basal diet increased (P