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Separate feeding of calcium improves performance and ileal nutrient digestibility in broiler chicks

Wilkinson, S. J., Selle, P. H., Bedford, M. R., Cowieson, A. J.
Animal production science 2014 v.54 no.2 pp. 172-178
amino acids, broiler chickens, calcium, calcium carbonate, choice feeding, digestibility, experimental diets, feed intake, ileum, minerals, nitrogen, phosphorus, weight gain
A total of 144 Cobb 500 broilers were used to investigate if modern commercial broilers could regulate their calcium (Ca) intake using choice feeding and whether separating the delivery of a portion of the Ca from the mixed ration would be advantageous for performance and nutrient recovery. Birds were fed corn+soy-based diets formulated to contain 2.5, 5.0, 7.5 or 10.0 g/kg total Ca and all groups had access to a separate Ca source (CaCO3). The trial was conducted from Day 1 to Day 21 and birds had ad libitum access to both the experimental diets and a separate Ca source throughout. Total feed and separate Ca intake were monitored daily, weight gain and feed intake weekly and on Day 21, the apparent ileal digestibility of DM, nitrogen, selected minerals and amino acids were determined. Consumption of the separate Ca source increased (P < 0.05) with decreasing total Ca concentration of the mixed ration. No differences (P > 0.05) in toe ash were found. Increasing dietary Ca concentration negatively influenced the apparent ileal digestibility of DM, nitrogen, minerals and amino acids. It can be concluded that broilers can select and consume Ca from a separate source to broadly maintain their requirement. Feeding a separate source of Ca in combination with reduced dietary Ca in the mixed ration had beneficial effects on nutrient digestibility, phosphorus excretion and performance.