Effect of diets with different energy and lipase levels on performance, digestibility and carcass trait in broilers

A 28-d trial was conducted to evaluate the effect of diets with different energy and lipase levels on performance, nutrient digestibility, serum profiles, gut health, and carcass quality in broilers.

A total of 720 one-day-old male Ross 308 broilers (45.4±0.5 g) were randomly assigned to one of the following four treatments: i) RET, reduced energy treatment (metabolizable energy = 2,950 and 3,100 kcal/kg for starter and finisher diet), ii) BDT, basal diet treatment (metabolizable energy = 3,050 and 3,200 kcal/kg for starter and finisher diet, iii) RET015, RET+0.15 g/kg lipase, and iv) RET03, RET+0.3 g/kg lipase. There were 10 replications (cages) per treatment with 18 birds per cage.

During d 1 to 14, broilers fed BDT, RET015, and RET03 diets had higher (p<0.05) body weight gain than those fed RET diet. During d 1 to 14, 15 to 28 and the overall experiment, feed conversion ratio in RET03 treatment was lower (p<0.05) compared with RET treatment. On d 14, the apparent total tract digestibility (ATTD) of dry matter (DM), ether extract (EE), and gross energy in RET03 treatment was higher (p<0.05) than those in RET treatment, while the ATTD of N was increased (p<0.05) by RET03 treatment. On d 28, broilers fed RET03 diet had higher (p<0.05) ATTD of DM than those fed RET and RET015 diets, while the ATTD of EE in BDT and RET03 treatments was increased (p<0.05) compared with RET and RET015 treatments. Broilers fed RET03 diet had higher villus height (VH) and VH:crypt depth (CD) ratio than those fed RET and BDT diets. The activity of pancreatic lipase in BDT and RET03 treatments was higher (p<0.05) than that in RET treatment.

Taken together, lipase supplementation (3,000 U/kg feed) increased growth performance, nutrient digestibility, VH, VH:CD ratio and lipase activity, but decreased triglyceride, low-density lipoprotein cholesterol and the abdominal fat percentage in broilers fed reduced energy diet.