Abstract

The experiment was conducted to evaluate the effects of different levels of Citrus sinensispeel extract (CSPE) on gastrointestinal microbial population of broilers. Four hundred Ross 308 one-day broilers in a completely randomized design with five treatments (fourreplicates per treatment and each replicate had 20 chicks) were categorized. Eachtreatment used regulatory diet including either 1000 or 1250 ppm (CSPE) in the drinking water and in two periods of 1^st to 21^st day and 1^st to 42^nd days or based diet without anyadditive for six weeks. Data analysis was performed using SAS software and mean comparison was conducted by Duncan method. The results determined that the mean of Lactobacilli in ileum on day 42 showed that the means of the treatments were significantly different (p < 0.05). The highest mean was related to 1250 ppm (CSPE) treatment up to the end of the rearing period and the lowest mean to the control treatment. The resultsdetermined that the mean of Lactobacilli in cecum on day 42 showed that the means of the treatments were significantly different (p < 0.05). The results determined that the mean of Escherichia coli in ileum on day 42 showed that the means of the treatments were significantly different (p < 0.05). The lowest mean was related to 1250 ppm (CSPE) treatment up to the end of the rearing period and the highest mean to the control treatment. The results determined that the mean of coliforms in ileum on day 42 showed that all the experimental treatments were significantly different from the control treatment(p < 0.05). The highest mean was related to the control treatment and the lowest meanwas related to 1250 ppm (CSPE) treatment up to the end of the rearing period.

Key words: Broilers, Citrus sinensis peel extract, microbial population, Salmonella.