Abstract

MINON-HUESCA, Ernesto et al. Biological and economic optimum levels of dietary copper in broilers. Agrociencia [online]. 2006, vol.40, n.2, pp.163-170. ISSN 2521-9766.

Copper (Cu) is used to promote growth in broilers. However, the optimum supplement level for improving productive performance is unknown. In the present study, an evaluation was made of the effect of eight levels (0, 50, 100, 150, 200, 250, 300, 350 mg kg−1) of Cu on the productive performance of sexed broilers, for the purpose of calculating the biological optimum level of Cu that maximizes weight gain (BOLWG), minimizes feed conversion (BOLFC), and the economic optimum level that maximizes profits (EOLMP). A completely randomized design was used with an 8×2 factorial arrangement. The means of the principal effects were compared with the Tukey test. Orthogonal contrasts were used to test linear, quadratic or cubic effects of the levels of Cu on productive performance. Econometric models were used to calculate the BOLWG, the BOLFC and the EOLMP. The levels of Cu did not affect the productive performance of the broilers of 1 to 21 d of age. The sex affected (p≤0.05) feed consumption, weight gain and live weight. In the stage of 22 to 42 d, differences (p≤0.05) were observed in feed consumption (CON), weight gain (WG), feed conversion (FC) and live weight (LW), due to the levels of Cu. The sex had no effect. Quadratic trends (p≤0.05) were detected for WG, FC and LW, and cubic (p≤0.05) for CONS and LW. The values for BOLWG, BOLFC and EOLMP were 122.99, 163.36 and 127.17 mg kg−1. The EOLMP was sensitive to the price changes of broilers.

Keywords : Dietary copper; maximum gain; maximum profit; minimum conversion; chicken.

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