Resumen

GODOY, Susmira et al. Growth and bone mineralization in chicken broilers fed with national phosphates. Zootecnia Trop. [online]. 2007, vol.25, n.4, pp.291-299. ISSN 0798-7269.

In order to determine the effect of different phosphorus sources on growth, bone mineralization, and phosphorus retention in birds, 440 male chicks of the commercial hybrid Cobb x Cobb, one day born, fed up to the fourth week on age, were distributed in five treatments, in a completely randomized design, using a factorial arrangement 5 x 2 (5 phosphorus sources, 2 levels of phosphorus additions), with four replications with 10 birds each. Phosphorus sources were calcinated bone (HHC), a fertilizer, triple superphosphate (SFT), and three raw rock phosphates, Riecito (RIO), Lizardo (LIZA), and Jají (JAJI). Phosphates were added to a basal diet (0.35% P) at two phosphorus levels (0.25 and 0.50%). Diets contained 3,100 kcal ME/kg, 23.5% CP, with a constant calcium level (1%). Body weight and feed intake were measured. Four birds per treatment were sacrificed to take both tibias to determine density, ash, and phosphorus. A balance technique was used to determine phosphorus net retention and utilization efficiency. Body weight (g/bird) at 0.25 and 0.50% P levels was greater (P<0.05) for SFT, followed by HHC, intermediate for RIO and JAJI and lower for LIZA, with values of 813 and 805, 747 and 745, 436 and 760, 393 and 661 and, 286 and 415, respectively, for treatments and levels. RIO phosphate was similar to HHC and SFT when added at 0.50% phosphorus level. Differences between levels were significant (P<0.05) only for sedimentary phosphates. Feed intake and feed efficiency showed similar tendency in relation to body weight. Bone ash content (%) for 0.25 and 0.50% added phosphorus, was higher (P< 0,05) for SFT followed by HHC, RIO, LIZA and JAJI, with values of 40.7 and 45.5, 38.7 and 43.7, 36.8 and 42.4, 35.0 and 40.1, and 33.2 and 38.2, respectively for phosphates and levels. Bone ash content expressed in mg/cm3 presented similar tendency to the percent expression. There were not differences in bone phosphorus content and values ranged were between 16.8 and 18.5%. Apparent phosphorus net retention (%) for 0.25 and 0.50% added phosphorus was greater (P<0.05) for SFT, followed by HHC, RIO, and LIZA and lower for JAJI, with values 76.4 and 73.7, 71.8 and 69.3, 71.5 and 65.5, 69.4 and 66.2, and 62.7 and 58.6%, respectively for the same order of treatments and levels. Phosphorus utilization efficiency (%) was greater for SFT (66.7) and HHC (63.1), followed by RIO (61.5) and LIZA (62.0) and lower for JAJI (57.0). It is concluded that sedimentary phosphates had variable limitations, depending upon deposit origin, for growing chicks feeding and that absorption measures showed similar tendency as body weight and bone mineralization, in relation to a better response for SFT, followed of HHC, RIO, LIZA and JAJI

Palabras clave : Phosphates; chicken; phosphorus bioavailability.

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