Impact different levels of probiotic on blood biochemical, carcass traits and nitrogen excretion of broiler chickens fed low protein diets

The study aims to know effect of different levels of probiotic on blood biochemical, carcass traits, nitrogen excretion, jejunum morphology and tibia traits of birds”. Two-hundred and fifty of 1-day-old Ross308 chicks were bought from a local hatchery. The birds were randomly divided into five treatments with five replicate (pen) and ten birds for each pen. The treatments were as follows: basal diet (Control); basal diet with lowering of protein level by 10% less than NRC recommendation without inclusion of probiotic (LP); LP with inclusion of probiotic by 50 mg /kg diet (LP+ P50); LP with inclusion of probiotic by 100 mg/kg diet (LP+ P100) and LP with inclusion of probiotic by 150 mg/kg diet (LP+ P150). The results indicated that lowering dietary protein and addition of probiotic did not affect on the concentration of protein, albumin and glucose in the serum blood (p>0.05). While the cholesterol and triglyceride were remarkably decreased (p< 0.01) in the LP+ P100 and LP+ P150 treatments compared to the control and LP treatments. The dressing percentage and percentage of breast and leg were remarkably improved (p< 0.05) in the LP+150 treatment compared to LP and LP+ P50 treatments. percentage of abdominal fat was the lowest (P = 0.0002) in LP+ P150 treatment followed by LP+P100 and control treatments compared to LP+ P50 and LP treatments. Reducing dietary protein and probiotic addition did not effect on percentage of wings, liver, heart and gizzard. The jejunum morphology was noteworthy enhanced in LP+ P150 and LP+ P100 treatments compared to other treatments (p = 0.04; p