Effects of high dietary levels of citric acid on productive performance, serum enzyme activity, calcium and phosphorus retention and immune response in broiler chickens

Abstract

Summary In total, 180 Ross 308 male broiler chickens were used to investigate the effects of 0, 30 and 60Â g of citric acid (CA) per kg of diet on productive performance, selected blood metabolites, immune response, and Calcium and phosphorus retention in 6 replicates of 10 birds each up to day 42 of age. Growth performance, daily feed intake, tibia phosphorous (P) retention and ileal digestibility of total P (tP) were improved by the diets containing 30Â g kg –1 of CA ( P<Â 0.01) but all variables were suppressed as CA increased to 60Â g kg –1 ( P<Â 0.01). Dietary CA at 30Â g kg –1 improved and at 60Â g kg –1 reduced the ileal digestibility of tP at day 35 of age ( P<Â 0.01). Diets containing 60Â g kg –1 of CA reduced plasma P and cholesterol concentration and serum alkaline phosphatase activity ( P<Â 0.05) and increased serum aspartate aminotransferase and lactate dehydrogenase activity ( P<Â 0.01) at day 42 of age. The percentages of bursa of Fabricius and thymus were greater in the birds fed on diets containing 60 and 30Â g kg –1of CA, respectively ( P<Â 0.01). It was concluded that inclusion of 60Â g kg –1of CA in the diet exhibits adverse effects in broiler chickens demonstrated by suppressed performance, reduced Ca and P retention in tibia and altered liver enzyme activity.