Efecto de la adición de minerales en agua o en alimento sobre variables productivas y fisiológicas en pollos de engorde bajo estrés calórico

in order to evaluate the effect of mineral supplying in water or feed on productive and physiological variables in broilers under acute and chronic heat stress during final growth stage an experiment was conducted. using a completely randomized design, a total of 195 broilers were randomly assigned to three treatments with 8 replicates of 8 birds each one. the treatments were t1 = basal diet with no mineral addition; t2 = basal diet plus mineral addition in feed; t3 = basal diet plus mineral addition in water, which were applied from 28 days of age. before this period all broilers were receiving a same balance diet. the composition of the mineral formula used was: nahco3 (0,83%); nh4cl (0,07%); nacl (0,30%), obtaining an electrolytes balance of 240 meq. between 28 to 35 days of age, all these groups of birds were subjected at 30 oc and the following day an acute heat stress was simulated using 36oc for 6 hours. at 28 to 36 days old the following parameters were measured: feed and water consumption, body weight gain, feed conversion index, body temperature (bt), hyperventilation level (hl) and mortality (m) during acute stress. an anova test was applied to all variables except m, which a chi-squared test was performed. no significant effects on productive variables were found with minerals adding, neither to the water nor to the feed. water consumption was 34% greater in t3 and t2 (p=0,016) regard to t1, which not received minerals. mineral addition in water reduced significantly (p=0,007) bt (42,80 ± 0,16 °c), hl (159,95 ± 4,93 breaths/min) and m was reduced until 22% during acute heat stress period. it is concluded that mineral supplying affects mostly physiological variables and mortality