Abstract

GONZALEZ, Carlos Augusto; CHICA, Javier Eduardo  and  BARAHONA, Rolando. EFFECT OF VITAMIN 1 α OH-D₃ AND 25-OH-D₃ ON PERFORMANCE INDICES AND BONE MINERALIZATION IN COMMERCIAL PULLETS. rev.udcaactual.divulg.cient. [online]. 2015, vol.18, n.1, pp.155-162. ISSN 0123-4226.

In high-confinement poultry production systems, there is high incidence of broken eggs, cage fatigue or tibial dyschondroplasia, which is part of a set of skeletal changes that reduce bird welfare, problems that have been associated with low blood circulating levels of the active metabolite of vitamin D (1,25-(OH)2-vitamin D₃) during the period of greatest tibia growth. In the present study, four treatments were evaluated: a control diet based on corn and soybean with 50g phytase per ton as a control treatment; 12.5g 1 alphahydroxy-cholecalciferol or 1α-OH D₃ "On Top"; 12.5g of 1α- OH D₃ "matrixed" or 5.52g of 25-hydroxy-cholecalciferol or 25-OH-D₃ "On Top". A completely randomized design with six replications using 960 Lohmann Brown pullets four weeks of age, housed in 24 pens with 40 birds each was used. There were no statistical differences for the average weight at 16 weeks (1493g), feed conversion (4.61) or mortality among birds assigned to different treatments. Tibia length did not differ between birds receiving different treatments, being 5.58, 7.97, 9.51 and 10.1cm at 4, 8, 12 and 16 weeks, respectively. Likewise, mineral content (%) in bone was not influenced by the source or by the inclusion level of vitamin D₃, averaging 21.64 for calcium, 17.18 for phosphorus and 38.54 for ashes. However, the inclusion of vitamin 1α-OH D₃ matrixed represented a 1.0% reduction in feed costs compared with the use of 25-OH-D₃ "On Top".

Keywords : Bone mineralization; calcium deposition; feed conversion; tibia length; vitamin D.

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