Resumo

PATINO P, René et al. Nutrient absorption in lambs fed diets containing different amounts of phosphorus. Rev.MVZ Cordoba [online]. 2013, vol.18, n.2, pp.3444-3451. ISSN 0122-0268.

Objective. Evaluate the effect of increasing P intake on nutrient digestibility, and compare the true and apparent absorption coefficients of P and Ca in lambs. Materials and methods. Twenty-four Santa Ines sheep, with an average weight of 33.6 ± 1.6 kg, were distributed into four treatments (0, 2, 4 and 6 g/day of supplementary P) with forage: concentrate ratio of 70:30. The study of apparent nutrient digestibility was conducted during the first week, using the total feces collection method. During the second week, after injection of 7.4 MBq of ³²P and 7.7 MBq of ⁴⁵Ca, apparent (AAC) and true (TAC) absorption coefficients of P and Ca were determined. The lambs were kept in metabolic cages. Results. The increase in P intake did not affect (p>0.05) dry matter, crude protein, NDF or ADF digestibility, but the TAC of P and Ca and mineral matter digestibility decreased. The AAC was not affected (p=0.10). A cubic relationship was observed between P intake and TAC (TAC=2.16-1.95X+0.55X²-0.04X³; R²=0.38) and linear relationship with the TAC of Ca (TAC=0.559-0.03X; R²=0.26). TAC and AAC values were different (p<0.001). Conclusions. The increase in P intake doesn’t impact organic matter digestibility, but does affect P and Ca absorption. Apparent digestibility is not a reliable parameter to determine the efficiency of P and Ca absorption.

Palavras-chave : Absorption; calcium; phosphorus; radioisotopes; ruminants.

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