Effect of Different Metabolizable Energy Diets on Broilers' Growth Performance, Nutrient Digestibility, Organ Weight, Fecal Score and Lesion Score.

This study was conducted to investigate the effect of diets with different metabolizable energy (ME) levels on broiler growth performance, nutrient digestibility, fecal score, organ weight and lesion score. A total of 1134 1-day-old Ross broiler chicks with an initial body weight (BW) of 44.33 ± 1.70 g were randomly assigned to three dietary treatment groups. There were 21 replicate pens per treatment, including 18 male birds per pen. The experimental period was divided into 3 phases and the diets were provided to broilers from days 1 to 34 of age: the starter (days 1-7), growing (days 8-20), and finishing (days 21-34). The dietary treatments included CON, basal diet (3200 Kcal/kg), TRT1, basal diet - 50 kcal/kg ME (3150 Kcal/kg), and TRT2, basal diet + 50 kcal/kg ME (3250 kcal/kg). The TRT2 group showed a reduced (p < 0.05) feed conversion ratio (FCR) compared to the TRT1 group during the growing phase. During the overall experimental period, TRT2 group broilers showed an increased (p < 0.05) average daily gain (ADG) and a reduced (p < 0.05) FCR than in the TRT1 group. However, there were no differences observed in feed intake (FI) and body weight gain (BWG), nutrient digestibility, fecal score, organ weight and lesion score. In conclusion, feeding a diet at 3250 kcal/kg ME from days 1-34 could be suitable for improving both average daily gain and feed conversion ratio in broiler chickens.