Abstract
A total of 800 day-old broiler chicks were assigned to four test diets to assess the efficacy of phytase, fermented from Aspergillus niger, and boron, as boric acid, on the growth performance and mineral profile in chickens. The dietary treatments included the basal diet and the basal diet supplemented with boron (20 mg/kg), phytase (500 phytase units/kg diet), or a combination of boron and phytase. The following parameters were measured: growth performance indices, serum biochemicals, ash and the mineral profile of the tibia, breast muscle, liver and excreta. Boron decreased the overall feed conversion ratio by 1.9% (P<0.05) but did not affect the body weight and feed consumption of chickens grown for 42 days (P>0.05). The performance indices were not significantly influenced by dietary regimens for the first 21 days of the experiment (P>0.05). The addition of boron alone and boron + phytase resulted in significant increases in the boron concentrations of serum, bone, breast muscle, liver and excreta (P< 0.001). The serum alanine aminotransferase activity of chicks fed phytase was higher (P<0.05) than all other treatments. The ash content and mineral composition of the breast meat, liver and tibia did not respond to individual or combined dietary modifications (P>0.05). The chickens administered a diet with boron excreted less Cathrough excreta. However, the ash content and Fe and Cu concentrations in the excreta increased in response to phytase supplementation (P<0.05). In summary, supplementation with boron alone improved the feed conversion efficiency of broiler chickens fed diets containing adequate levels of nutrients. However, the combination of boron and phytase did not cause further improvements in broiler performance or the bioavailability of minerals.