Effect of dietary acidification on some blood parameters and weekly performance of broiler chickens

A total number of 90 Ross 308 broiler chickens were randomly divided into three treatments with three replicates of 10 chicks each. The first treatment having 0% citric acid was served as control and fed corn-soybean meal base diet. While, the other two treatments were received the basal diet supplemented with citric acid at different levels of 3 and 6%, respectively. The experiment was lasted for 42 days. Some blood parameters (metabolites of serum, enzyme activities and plasma mineral concentrations), gastrointestinal tract (GI-tract) morphology and weekly performance were measured. The results indicated that diets including citric acid had significant effect (P<0.01) on weekly feed intake, body weight gain and body weight but there was no significant improvement on feed conversion ratio during any experimental weeks. Also, citric acid had significant effect on carcass yield (P<0.01) and relative heart weight (P<0.05) but had no significant effect on relative weights of liver and abdominal fat. The effect of citric acid was significant on GI-tract morphology, cholesterol concentration, serum alkaline phosphatase and lactate dehydrogenase activities (P<0.05) but did not significantly affect urea, triglycerides, total protein concentrations and serum alanine aminotransferase and aspartate aminotransferase activities. Dietary effect of citric acid was significantly shown on plasma P and Fe concentrations (P<0.05) but not shown on plasma Ca, Mg and Zn concentrations. The results showed that addition of 3% citric acid significantly improved weekly growth performance but adding 6% citric acid had a negative effect on weekly performance factors of broiler chicks.