Ciência e Agrotecnologia
Print version ISSN 1413-7054
SILVA, Hunaldo Oliveira et al. Phytase in rations of growing pigs: performance, blood parameters and bone mineral content. Ciênc. agrotec. [online]. 2004, vol.28, n.6, pp.1428-1436. ISSN 1413-7054. http://dx.doi.org/10.1590/S1413-70542004000600028.
It was intended with the present work to verify the effect of phytase on the performance, bone mineralization and content of plasma urea of swine. 80 swine (30 ± 3.1 kg/LW), crossbred (LD x LW) males and females, allocated to a randomized block design (RBD) with four treatments and five replicates. The treatments consisted of a growing swine diet on the basis of corn, soybean meal and defatted rice bran (DRB) supplemented with four levels of phytase (0, 400, 800 and 1200 FTU/kg) The diet was formulated to meet the requirements of growing swine except for available calcium and phosphorus, the levels of which were 0.64 and 0.25%, respectively. The enzyme phytase utilized was Natuphos 5000. Over the experimental period every eight days, blood of two animals per block was collected through a puncture in the sinus orbital, to determine the plasma urea content. At the final of the experimental period, two animals were slaughtered for collection of the metacarpus bone, aiming to verify the mineral content. The variables analyzed were: daily average weight gain (DAWG), daily average ration consumption (DARC), feed conversion (FC), content of plasma urea, content of ashes, calcium, phosphorus, manganese, zinc and magnesium in the bone. The phytase levels provided a linear improvement (P<0.05) on feed conversion and a quadratic effect on swine's plasma urea content. Phytase promoted a linear increase (P<0.05) on the content of calcium and phosphorus in the swine's metacarpus bone. The level of 750 FTU/kg provided the lowest plasma urea content. It is concluded that the use of the enzyme phytase in growing swine diets improved feed conversion, decreased the plasma urea content and increased the contents of calcium and phosphorus in the bone.
Keywords : Enzyme; minerals; plasma; urea.