Estimación de excreción fecal en alpacas (Vicugna pacos) bajo condiciones estabuladas usando dióxido de titanio

The aim of this study was to estimate the production of faeces in alpacas with the use of titanium dioxide (TiO2). A square 4x4 Latin design was used, with four animals, four treatments and four periods. Each period last for 14 days of evaluation and seven days of rest. The treatments were: T2.5 (1), 2.5 g of TiO₂/animal/day; T1.25(2), 2.5 g of TiO₂/animal/day divided into two doses (07:00, 16:00); T5(1), 5 g of TiO₂/animal/day; T2.5(2), 5 g of TiO₂/animal/day divided into two doses (07:00, 16:00). The percentages of the recovery of TiO₂ were 90, 82, 78 and 52% for T2.5(1), T1.25(2), T5(1) and T2.5(2), respectively, being T2.5(2) different from the other treatments (p=0.00013). The parameters of the TiO₂ excretion pattern were: intercept of the curve of TiO₂ excretion at time zero (a), maximum excretion of TiO₂ at time (b), constant rate of excretion of b (c), time needed of excretion of TiO₂ so that it has excreted half of the initial concentration (T_1/2), and time to reach the balance of excretion of the marker (T _(a+b)). There was no difference between treatments for the values of a, c, mean T and T, but there was a significant difference in the value of b between the administration of the marker of 2.5 vs 5 g (p<0.0001). The averages of faecal production estimated with TiO₂ vs. faecal production observed directly was different in T1.25(2), T5(1) and T2.5(2) (p<0.05), but not in T2.5(1). In conclusion, the time in which the excretion equilibrium of TiO₂ is reached is approximately eight days and the dose of 2.5 g of TiO₂ once a day more accurately estimates faecal production in alpacas.