The objective of the current study was to investigate the cumulative effects of purine and pyrimidine nucleosides on performance, gut morphology, digestive enzymes and immune system in broilers from 0 to 21 days of age. A total of 360 day-old male chicks (Cobb 500) were randomly assigned to 4 experimental diets with 6 replications of 15 birds each in a completely randomized design. Experimental diets were 1) control diet based on maize-soybean meal which supplemented with following nucleosides: 2) 0.05% Adenosine+0.025% Uridine+0.025% Cytidine (AUC); 3) 0.05% Guanosine+0.025% Uridine+0.025% Cytidine (GUC); 4) 0.025% Adenosine+0.025% Guanosine+0.025% Uridine+0.025% Cytidine (AGUC). Body weight and feed intake of birds were measured on days 10 and 21 to calculate the average daily gain, average feed intake and FCR. On days 11 and 21, 2 birds per cage (12 birds/treatment) were selected to collect blood samples and euthanize to obtain jejunal, bursa and spleen samples. Results showed that AUC significantly increased body weight and average daily gain, intestinal villus height and width, activity of brush border enzymes (alkaline phosphatase and aminopeptidase). AUC and AGUC significantly increased high density lipoprotein and uric acid, respectively, while dietary nucleosides did not affect cholesterol and triglyceride concentrations in serum samples. AUC significantly improved immune indices such as the relative weight of the Bursa of Fabricius and the concentration of Ig A. In conclusion, the present study clearly demonstrated that combination of adenosine+uridine+cytidine could be useful feed additive for improving economically important traits in broilers.

Keywords