A series of experiments were envisaged to evaluate the effect of supplementation of dietary electrolytes with applicability of dietary electrolyte balance by using different salts on growth and carcass responses, body physiological responses and litter condition of modern day broiler chickens under phase feeding system.
Day-old straight-run Hubbard broiler chicks were randomly allocated to eight dietary treatments replicated four times in such a way that a floor space of 0.09 m2 was provided to each bird. Birds were housed in environmental control system. Continuous light was provided 24 hours for the first 3 day and thereafter a light pattern of 23L:ID was adopted for the entire experimental. In each experiment, a basal diet was formulated having lowest level of each electrolyte. In experiment 1, Na and DEB in the basal diet were maintained at 0.08% and 160 mEq/kg, respectively. This basal diet was then supplemented with sodium bicarbonate (NaHCO3) and disodium sulphate (Na2SO4) to maintain four levels of Na (0.17, 0.26, 0.35, and 0.44%) by fixing K and Cl with DEB 200, 240, 280 and 320 mEq/kg, respectively. In experiment 2, a basal diet was prepared to contain the lowest level of K and DEB i.e. 0.70% and 160 mEq/kg, respectively. This basal diet was supplemented with potassium sulphate (K2S04) and potassium carbonate (K2C04) by fixing Na and Cl. So, four levels of K (0.86, 1.02, 1.18, and 1.34%) were maintained in eight dietary treatments. In experiment 3, a basal diet was prepared to contain the lowest level of Cl and DEI3 i.e. 0.17% and 320 rnEq/kg, respectively. This basal diet was supplemented with ammonium chloride (NH4CI) or calcium chloride (CaCl2), so that, in each diet, we can have the increase of 40 mEq/kg DEB at 0.3 I, 0.45, 0.59 and 0.73% of Cl at DEB 280, 240, 200 and 160 mEq/kg, respectively, by fixing Na and K.

At the end of each phase (pre-starter, starter, grower and finisher); data of feed intake, weight gain, feed to gain ratio, mortality, water intake, water intake-to-feed intake ratio and litter quality were collected and evaluated. At the end of each experiment, two birds were slaughtered for their carcass and body physiological responses. Blood was also collected from these same birds for blood pH. glucose and serum mineral analyses. For statistical analyses, four (4) levels of electrolyte were used with two (2) sources of salt in a factorial arrangement of 4 x 2 under completely randomized design using GLM.

In experiment 1, highest weight gain and feed intake were found in birds consuming 0.17% (NaHCO3) and 0.44% (Na2SO4) dNa, respectively during d 1-10. However during d 11-20, weight gain and feed:gain were reduced with same levels of dNa. Maximum weight gain was found in diets containing 0.17 and 0.24% dNa during d 21-33 and 34-42, respectively. Improved FG was the result of diets containing 0.20% (NaHCO3) and 0.37% (Na2SO4) dNa during d 2 1-33. Linear rise in water intake was observed in birds with increasing dNa during d 1-42. Minimum litter dampness was seen at 0.37% (NaHCO3) and 0.2 1% (Na2SO4) during d 1-10. Minimum and maximum mortality were observed at 0.37% level of dNa in case of supplementation of NaHCO3 and Na2SO4, respectively. Significantly increased pH and kidney weight while reduced dressing percentage were observed by amount and salt of dNa. Increased breast, thigh and gizzard weights were observed with increasing sodium. Weights of pancreas, gall bladder, bursa, and lungs, and shank length were affected by interaction of amount and salt of dNa.

In experiment 2, BWG (P0.03) and feed:gain (P0.05) was improved at 1.20% dK during 32 to 42 d of age. K2S04 supplemented diets increased feed intake during I to 10 d (P<0.05), water intake during 34 to 42 d (P0.04) and mortality during 1 to 42 d (PE0.02). Water intake was increased linearly with increasing dK when supplemented by K2C03 whereas this was decreased linearly with increasing dK with that of K2S04 during 11 to 20 d (P0.002). The K2S04 supplemented diets lowered the blood pH (P0.00l), dressing (P0.04), abdominal fat (P0.03) weights and shank length (P0.02). A significant salt x dK effect was observed where low levels of dK with K2C03 and high levels with K2504 exhibited lower litter moisture during all phases. Increasing concentration of serum cations was observed by increasing dK, by balancing of increasing serum HCO3 with decreasing Cl at the end of the experiment.

In experiment 3, body weight gain and water consumption were optimized at 0.73%, and 0.73% (CaCI2) and 0.45% (NH4CI), respectively, during d 1-10. During d 2 1-33, maximum weight gain and feed intake were observed at 0.42%, and 0.63% (CaCI2) and 0.63% (NH4CI), respectively. Highest weight gain (0.60% dcl), feed intake (0.61% CaCI2 0.42% NH4CI) and mortality (0.73%) while improved feed:gain (FG; 0.38% dCl) were obtained by interaction effects of amount and source of dCl during d 34-42. Fl (0.60%), feed:gain (0.3 8%) and litter moisture (0.31% NH4CI; 0.35 CaCl2) was affected during I -42d by amount of dcl. Increased blood pH, serum glucose and dressing percentage were found by dCl and replacing CaCI, with NH4C1. Improved breast meat, thigh meat and shank length while reduced abdominal fat were observed by replacing salts (CaCI2 withNH4Cl).

It is concluded that birds showed better growth performance and reduced mortality against high levels of dietary sodium in Na2SO4 than NaHCO3 supplemented diets, while significant rise in pH, breast and thigh meat yield while reduced dressing percentage were observed with increasing dietary sodium. The importance of high concentration of dK for better weight gain and feed efficiency was depicted in later stages of production. K2C03 increased survivability and dressing responses but both dK levels and salts played important role for water intake, litter condition, carcass characteristics and serum mineral concentration. Birds were also suggested to be more sensitive to amount and source of dC1 in later part of their life.