The Digestibility of Organic Trace Minerals along the Small Intestine in Broiler Chickens

An experiment was conducted to evaluate the effects of low concentrations of organic and inorganic dietary trace minerals on broiler performance and trace mineral digestibility along the small intestine of 35-day-old broiler chickens reared under floor-pen conditions. Eight hundred male, day-old Cobb broiler chickens were randomly allocated to 4 dietary treatments (25 birds per pen with 8 replicates per treatment). Broilers fed diets supplemented with 4, 20, 40 and 30 mg/kg, respectively, of Cu, Fe, Mn and Zn from organic chelates and inorganic salts achieved the same body weight gain as those supplemented at the NRC levels (8 mg Cu, 40 mg Fe, 60 mg Mn and 40 mg Zn/kg, respectively) from inorganic salts. However, birds fed a control diet without any supplementation at dietary levels of 7.4-8.8, 60.1-69.2, 14.6-15.4 and 19.1-20.6 mg/kg of Cu, Fe, Mn and Zn, respectively, had decreased feed intake and growth rate. There was no significant difference in the digestibility of Cu in all regions of the small intestine. Throughout the small intestine the apparent absorption of Mn from both organic and inorganic sources was small, whereas the digestibility of Zn seemed to be more complex, exhibiting differences in the apparent absorption due to both mineral source and intestinal site. Therefore, the digestibility of organic Zn was improved (p<0.01) in the ileum compared to inorganic Zn. The digestibility of Zn in the duodenum was smaller (p<0.05) than that in the ileum.