The objective of this research was to evaluate the effect of different ionophores and acid-base balance of diets (DEB) on young broiler chicks (one to twenty one days of age) performance and incidence of tibial dyschondroplasia (TD). One thousand and sixty one day old "Cobb" male broilers chickens were allotted to a completely randomized design in 3 x 2 factorial arrangement (DEB = 230, 260 and 290 mEq/kg x ionophores = lasalocid e salinomicin) and two control treatments (230 and 260 mEq/kg). The ionophores x DEB interaction, for weight at 21 days (W21) and feed intake (FI), was unrolled and, by using lasalocid, it was observed quadratic effect, in function of DEB levels for W21 and FI. Minimum values for these variables were obtained at levels of 261 and 268 mEq/kg, respectively. When salinomycin was used, DEB effect was observed. Feed: gain ratio was influenced neither by ionophores nor by DEB. In the contrasts comparison, the better W21 was observed when the ionophores were added to the diets, but for the feed intake and feed: gain ratio no differences were observed. In the comparisons between ionophores, the birds fed salinomycin showed better weight than those fed lasalocid. There was no effect of salinomycin on the epiphysis areas, independently of DEB, however, when lasalocid was used, these areas increased, as DEB levels increased. It was concluded that the use of diets with lasalocid reduced the broiler chicks performance, and the birds fed salinomycin showed better W21 and were not affected by DEB on TD incidence. However, when lasalocid was used, the bone areas increase, that characterized TD, as DEB levels increased.
coccidiostatic; acid-base balance; lasalocid; leg problems; salinomycin
