مقايسه زيست فراهمى منابع تجارى مختلف دى كلسيم فسفات در جوجه هاى گوشتى

Application

Environmental and economic concerns regarding phosphorus (P) in broiler production pledge a reduction in dietary P provision. However, to maintain growth performance and bone mineralisation, optimisation of P utilisation appears crucial.

Introduction

In broilers, P is involved in many essential functions, representing a Ney element in the maintenance of growth performance and bone mineralisation (Le ́ tourneau-Montminy et al., 2010). Thus, it must be of major concern that current economic and environmental pressures leading to an unavoidable decrease in dietary P supply represent a threat to animal productivity. Then it is necessary to find P sources with high levels of bioavailability. The aim of the present study was to determine the bioavailability of P from six commercial sources of dicalcium phosphate (DCP2: 17.75% P; DCP3: 17% P; DCP4: 17% P; DCP5: 18.5% P; DCP6: 17% P; DCP7: 18.06% P) relative to standard source (P1=Phosphoric acid 85%, contains 26.87% P), for broiler chicNs.

Material and methods

A total of 440 1-d-old Ross-308 female broiler chicNens were randomly allotted to 1 of 4 replicate cages (5 chicNs/cage) for each of 22 treatments in a completely randomized design involving seven P sources and 3 levels of added P (0.15, 0.30, or 0.45%) plus a control diet containing 0.15% available P. Feed and water were available ad libitum for an experimental phase of 42-d. Data were analysed using the GLM procedure of SAS. Duncan’s multiple range test was used to determine differences among treatment means at P<0.05. Relative bioavailability values of P were estimated using P1 as the standard source by slope ratio comparison from multiple linear regressions (Little et al., 1997).

Results

Body weight gain (BW), average daily feed intaNe, FCR, carcass and breast fractional weight, alNaline phosphatase (ALP), tibia characteristics (length (L), ash content, bone strength (BS)) were different significantly, between P levels and sources at 42d. Based on slope ratios from the linear regression of BW, FCR, ALP, BS, L and ash%, on added levels of available P, the bioavailability of P in source no. 2, 3 and 7 were the same, relative to phosphoric acid.

Conclusion

Phosphorous originated from sources no. 2, 3, 5 and 7 were 20% and 40% more available to broilers than sources no. 4 and 6, respectively, in enhancing tibia length (Figure 1).

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