Influence of varying sources of dietary electrolytes on the performance of broilers reared in a high temperature environment

Abstract

Experiment using 297 broiler chicks, kept from 1 to 42 days under cyclic heat stress (minimum 29.3 °C and maximum 38 °C), was conducted to investigate the relative efficacies of three sodium (NaHCO 3, Na 2CO 3, Na 2SO 4), and potassium (KHCO 3, K 2CO 3, K 2SO 4) supplements at an identical dietary electrolyte balance (DEB) 250 mEq/kg and two chloride supplements (CaCl 2 and NH 4Cl) at DEB 50 mEq/kg. The desired levels of DEB were achieved by substitution of individual mineral supplement at the expense to builder's sand in the basal starter (DEB 185.6 mEq/kg) and finisher (DEB 174 mEq/kg) diet containing only salt as a source of Na and Cl. Each diet (one basal and eight experimental) was fed to three experimental units having 11 chicks each. The growth performances in K supplements, except KHCO 3, were poorer than those of Na supplements. The NaHCO 3, Na 2CO 3, Na 2SO 4 and NH 4Cl increased body weight gain, feed intake and improved feed to gain ratio than those of K 2CO 3 and K 2SO 4 after 42 days of age. These supplements also increased the water intake and resulted in lowered body temperature as well as reduced mortality. Very poor performance in CaCl 2 supplement was associated with disturbed calcium:phosphorus and very low blood pH (7.19). Better performance was noted with bicarbonate than that with carbonate and sulfate sources. The KHCO 3 accentuate the respiratory alkalosis by increasing blood HCO 3 contents (26.09 mmol/l) and gave poorer performance than NaHCO 3. Blood lymphocytes, hemoglobin, hematocrit and electrolyte balance in heat stressed broilers were better improved by NH 4Cl, NaHCO 3, Na 2CO 3, Na 2SO 4 and KHCO 3 than those of CaCl 2, K 2CO 3 and K 2SO 4 supplements. Present findings emphasized the importance of considering metabolisable anions supplemented in association with cations while balancing the dietary electrolyte equations. That is why DEB equation cannot be used to predict the relative benefits of different mineral supplements.