The present study aimed to investigate the effect of incorporation of increasing levels of two organic acid salts as acidifires (calcium propionate and calcium lactate) in Nile tilapia (Oreochromis niloticus) diets. Therefore seven experimental diets were formulated to be isocaloric (2600 Kcal/kg diet metabolizable energy) and isonitrogenous (30% crude protein). The first one represented the untreated diet (control), the other six diets were supplemented by Ca-propionate (D2, D3 and D4) and Ca-lactate (D5, D6 and D7). For each organic salt three doses were supplemented to the diets (0.5, 1.0 and 1.5%), respectively. The initial body weight for fish received the different treatments ranged between 1.16 and 1.19 g. At experiment termination (after 90 days) results showed that, fish fed the diet supplemented by 1% Ca-lactate (D6) showed the highest significant BW (16.00 g) and control group showed the lowest BW (12.80 g).
Compared to control diet (D1) the other supplemented diets by organic salts significantly increased BW and the same trend was also observed for body length (BL), weight gain (WG), Specific growth rate (SGR), Feed intake (FI), feed conversion ratio (FCR) and protein efficiency ratio (PER). Supplementation of the basal diets with Ca-propionate or Ca-lactate by the different tested doses (0.5, 1.0 or 1.5%) significantly improved Apparent digestibility coefficients (ADC) for lipids and crude protein and decreased ADC for carbohydrates. And the same trend was also observed of mineral absorption whereas supplementation of the experimental diets by either of Ca-propionate or Ca-lactate significantly (P