Efficiency of microbial phytase supplementation in diets formulated with different calcium:phosphorus ratios, supplied to broilers from 22 to 33 days old.

Autor: Naves LP; Department of Animal Science, Federal University of Lavras, Lavras, Brazil., Rodrigues PB; Department of Animal Science, Federal University of Lavras, Lavras, Brazil., Teixeira LDV; Department of Animal Science, Federal University of Lavras, Lavras, Brazil., de Oliveira EC; Department of Animal Science, Federal University of Lavras, Lavras, Brazil., Saldanha MM; Department of Animal Science, Federal University of Lavras, Lavras, Brazil., Alvarenga RR; Department of Animal Science, Federal University of Lavras, Lavras, Brazil., Corrêa AD; Department of Chemistry, Federal University of Lavras, Lavras, Brazil., Lima RR; Department of Exact Sciences, Federal University of Lavras, Lavras, Brazil.
Jazyk: angličtina
Zdroj: Journal of animal physiology and animal nutrition [J Anim Physiol Anim Nutr (Berl)] 2015 Feb; Vol. 99 (1), pp. 139-149. Date of Electronic Publication: 2014 Mar 31.
DOI: 10.1111/jpn.12186
Abstrakt: An experiment was conducted with broilers from 22 to 33 days of age to evaluate the efficiency of six microbial phytases supplemented in diets (1500 FTU/kg) that were formulated with three different calcium:available phosphorus (Ca:P(avail)) ratios (4.5:1.0, 6.0:1.0 and 7.5:1.0). A positive control diet without phytase was formulated with a Ca:P(avail) ratio of 7.5:3.4 to meet the nutritional requirements of the broilers. The P and ash contents of the tibia, magnesium in the plasma, performance, balance and retention of phytate phosphorus (P(phyt)), intake of total P and nitrogen (N), nitrogen-corrected apparent metabolizable energy and apparent digestibility of dry matter of the diets were not influenced (p > 0.05) by the type of phytase or the dietary Ca:P(avail) ratio. However, there was an interaction (p < 0.05) between the phytase type and the Ca:P(avail) ratio for the retention coefficients of total P, Ca and N. Phytase B resulted in the highest Ca deposition in the tibia (p < 0.01). Phytases D, E and F reduced the Ca concentrations in the tibia (p < 0.01) and plasma (p < 0.05). Phytase D increased the P level in the plasma and decreased the total P excretion (p < 0.01). Phytases E and F increased Ca excretion, while phytase A reduced it (p < 0.01). Regardless of the phytase type, increasing the dietary Ca:P(avail) ratio reduced (p < 0.05) the plasma P concentration and the excretion of total P and N and, conversely, increased (p < 0.05) the plasma concentration, intake and excretion of Ca. For the rearing period evaluated, it is possible to reduce the P(avail) of the diet to 1.0 g/kg when Ca is maintained at 7.5 g/kg, and the diet is supplemented with 1500 FTU of phytase A, C, D or E/kg. This diet allows the maintenance of performance and adequate bone mineralization, and it improves the Ca, total P and P(phyt) utilization in addition to reducing the excretion of N and P into the environment.
(Journal of Animal Physiology and Animal Nutrition © 2014 Blackwell Verlag GmbH.)
Databáze: MEDLINE
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