| Popis: |
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 (p0.05) la digestibilidad aparente de la materia seca, proteína bruta, FDN o FDA. El CAV de Ca y de P y la digestibilidad de la materia mineral presentaron una reducción. EL AAC no fue afectado (p=0.10). La ecuación CAV=2.16-1.95X+0.55X²-0.04X³ (R² = 0.38) explicó la relación entre el CAV de P y el incremento en su ingestión, y la ecuación TAC=0.559 - 0.03X (R²=0.26), la relación entre el CAV de Ca y la ingestión de P. Los valores de AAC y CAV difirieron entre sí (p |
