Growth, water intake, litter moisture, carcass and physiological traits of broiler chickens fed varying levels and sources of potassium under phase feeding system

The concept of dietary electrolyte balance (DEB) was evaluated using 1-d-old straight-run Hubbard broiler chicks (total, 1472) and 4 dietary K (dK) levels (0.86%, 1.02%, 1.18%, and 1.34%) and 2 sources of dK salt (K2CO3 and K2SO4) in a 4×2 factorial arrangement of treatments. The 4 dK levels corresponded to DEB values of 200, 240, 280, and 320 mEq/kg, respectively. Each of the 8 dietary treatments was randomly allocated to 4 replicates with 46 birds per replicate. The experimental diets were prepared separately for each phase, i.e., prestarter (d 1–10), starter (d 11–20), grower (d 21–33), and finisher (d 34–42). Analyzed water characteristics (pH, temperature, salinity, dissolved oxygen, electrical conductivity, and total dissolved solids) and electrolytes were found within the recommended range. Feed intake (P=0.05), daily water intake (P=0.04), and mortality (P=0.02) were increased by replacing K2CO3 with K2SO4. The source and level interaction was found to affect litter moisture (P=0.04). Either varying levels or replacing salts of dK did not result in improved growth performance that was mainly associated with the simultaneously reduced capacity of the digestive (gizzard and proventriculus) and lymphoid (bursa and spleen) organs of the body. The dK and changing salt (K2CO3 with K2SO4) resulted in a greater dressing percentage (P=0.008), abdominal fat (P=0.03), and blood pH (P=0.01) but did not affect body, breast, and thigh weights. Increasing serum K, Na, and HCO3 were compensated with reduced serum Ca and Cl in higher dK diets. It is inferred that lower levels of dK (i.e., 0.86%) could be used to enhance broiler growth. The supplementation of K2SO4 improved feed and water intake, but reduced livability. The increasing supplementation of dietary K from K2SO4 improved carcass responses and reduced the digestive and lymphoid organ capacity.