Abstract
In this work, the effects of the addition of probiotics and citric acid to drinking water on performance, serum biochemistry, relative organ weight and carcass characteristics of broiler chicks were evaluated. Two hundred forty-one-day-old chicks (female Ross 308) were divided into 6 groups and submitted to 6 different treatments for 42 days, with 4 replicates in each treatment, with 10 birds in each. Drinking water was supplemented with a commercial probiotic mixture (Lactofeed®, Takgene Co, Iran) at 0 (control), 0.1 g/L (day 1 to 21) and 0.05 g/L (day 22 to 42), and citric acid at concentrations of 0 (control), 0.2 and 0.4% (day 1 to 42). Compared with controls, no significant changes (P>0.05) were found in the performance, serum biochemistry parameters and relative organ weights of broiler chicks receiving water supplemented with probiotics or citric acid after 42 days of experiment. However, a significant (P<0.05) interaction effect was observed between probiotic and citric acid supplementation on feed intake within the first 21 days. Moreover, chicks receiving water supplemented with probiotic and 0.2% of citric acid had highest (P<0.05) body weight at 42 days of age, as well total carcass weight. Results indicate that water supplementation with Lactofeed® and 0.2% of citric acid are promising strategies to enhance growth performance of broilers.