Effect of Dietary Sodium Nitrate Consumption on Egg Production, Egg Quality Characteristics and Some Blood Indices in Native Hens of West Azarbaijan Province

The aim of the study was to evaluate the effect of sodium nitrate consumption on egg quality and quantity, and some blood parameters of native breeder hens of West Azerbaijan province. One hundred native hens were used from wk 25 to 32 of age. These birds were divided into two groups. One group was fed the control diet (CD) but the other fed the same diet supplemented with 4.2 g/kg sodium nitrate (ND). After 2 wks of adaptation, eggs were collected daily and egg mass and egg production were measured weekly for five weeks. To assess the egg quality parameters, two eggs from each replicate pen were collected for three consecutive days each week. At the end of experimental period (wk 32 of age), blood samples of 5 birds per replicate were collected from the wing vein into anticoagulant tubes. Dietary sodium nitrate didn't affect the egg production, shell stiffness, shell thickness and Haugh unit (p>0.05) but it decreased the both egg production and egg mass during the last three weeks (wks 30, 31 and 32) (p<0.05). Furthermore, a treatment effect was observed for yolk colour (p<0.05). Both the egg production and egg mass were increased over time (p<0.05). No significant treatment${\times}$time interaction was observed for egg weight, egg production and egg mass (p>0.05). No effect of time or treatment${\times}$time were observed for shell stiffness (p>0.05). Over time, shell thickness was decreased while Haugh unit increased (p<0.05). None of the blood TP and TG or the activity of ALT, AST and LDH enzymes were affected by dietary consumption of sodium nitrate at wk 32 of age (p>0.05). Sodium nitrite decreased both the TAC and TC at wk 32 of age (p<0.001). It was concluded that the lower body antioxidant capacity of nitrate fed birds resulted in the lower performance (egg weight, egg production and egg mass).