A basal diet (0.8 g/kg dNa) was formulated in which each of the two sources ($NaHCO_3$ and $Na_2SO_4$) were supplemented in such a way to attain four levels (1.7, 2.6, 3.5, and 4.4 g/kg) of total dNa, respectively, under $4{ imes}2$ factorial arrangement. Eight dietary treatments were replicated four times, with 40 birds in each replicate (n = 1,280). The diets supplemented with $Na_2SO_4$ to attain higher levels of dNa showed highest BW gain and feed intake (FI) during d 1 to 10 (interaction effects) while 2.6 g/kg dNa exhibited improved BW gain and gain:feed (FG) during d 11 to 20. Linear rise in daily water intake (DWI) was associated with diets containing increasing dNa during d 1 to 42 ($p{leq}0.036$). During the first 10 d, DWI:FI was found highest in $NaHCO_3$ diets while $Na_2SO_4$ diets showed highest DWI:FI during last 10 d of the experiment ($p{leq}0.036$). Increasing dNa and changing $Na_2SO_4$ with $NaHCO_3$ salt increased pH and resulted in poor growth performance. Dressing weight ($p{leq}0.001$) and abdominal fat ($p{leq}0.001$; quadratic effect) were reduced, whereas breast ($p{leq}0.001$) and thigh (p<0.001) weights were aggravated with increasing dNa (linear effects). Present findings suggested higher levels of dNa from $Na_2SO_4$ as the supplemental salt in broiler diets would produce better growth performance, especially in first ten days of life, and improve carcass and body organ characteristics.