NR 46. Growth and bone mineralization of sheep fed with high fluorine phosphates

To evaluate the effect of phosphate with high levels of fluorine on growth and bone mineralization of sheep, triple superphosphate (SPT) and two raw rock phosphate, Riecito (RIO) and Monte Fresco (MONTE) vs dicalcium phosphate (DICAL), 24 West African sheep with an initial body weight 14.5 kg were assigned to the phosphorus sources in a complete randomized design. The animals were fed with forage, Pennisetum purpureum, ad libitum and supplemented with one kg/animal/day of a concentrate with 36.2 % corn cobs, 38.2 % corn, 9.3 % molasses, 6.3 % soy, 2.9 % urea and the different phosphates sources to provided 0.2 % total phosphorus. The diet were isocaloric (2.2 Mcal EME/kg) and isoproteic (24 % PC), with 1 % of calcium. The duration of the experiment was 15 months with the body weight controls every 28 days, forage intake every two weeks and water ad libitum. At the end of the experimental period 4 animals/treatment were injected trough the jugular vein with 200 mCi 32P and a oral dose of 200 mCi 45Ca. Seven days later biopsy of ribs were carried out to measure bone mineralization and the uptake of the radioactive material. The final weight (kg/animal) was higher (P<.05) for DICAL (34.4) and RIO (33.3) in relation to MONTE (30.5) and SFT (29.9). The daily body gain (g/animal/ day) was 113.62, 108.56, 89.38 and 73.53 for DICAL, RIO, MONTE and SFT, respectively, being the values significantly higher for DICAL and RIO. The intake of the supplement (g/animal/day) was higher (P<.05) for DICAL (883.0) with no significant differences with RIO (818.6) and MONTE (830.2) and lower for (SFT). Bone mineralization measured in terms of density (g/cc), bone ash, calcium, phosphorus (%, mg/cc) was grater for DICAL and SFT in relation to RIO and MONTE. Bone specific activity was lower for DICAL (9.13 and 0.72) than RIO (17.82 and 1.52), MONTE (29.28 and 2.15) and SFT (12.24 and 1.54), both for 32P (x10-4 cpm) and 45Ca (x10-7 cpm), respectively. The accumulation of fluorine in the bone tissue was higher (P<.05) for SFT (3133) and MONTE (2667) in relation to RIO (2433) and DICAL (816.7)