Two hundred and forty, one day old unsexed Arbor Acres broiler chicks were
used to examine the effect of supplementing pectinase enzyme (PE) with varying levels of
metabolizable energy (ME) on growth performance, quality of carcass and meat, and feeding
cost. Chicks were randomly allocated into six treatments (2x3 factorial design) each had four
replicates (n=10). Chicks were fed corn-soybean diet supplemented with two levels of
pectinase enzyme (0 and1000 U/kg), and three ME levels which were standard strain
recommendation (STD), 100 kcal lower than STD (E100) and 150 kcal lower than STD
(E150) of each feeding phase. The dietary ME values were 3000, 2900 and 2850 kcal/kg diet
at starter phase; 3100, 3000 and 2950 kcal /kg at grower phase; and 3200, 3100 and 3050
kcal/kg at the finisher phase. All diets were formulated to save the strain requirements from
the rest of nutrients. All chicks were housed in open system broiler house and received the
same managerial conditions and veterinary program during experimental period (1-40 d of
age). Parameters of growth performance, carcass characteristics, physical and chemical
evaluation of broiler meat were carried out and feeding cost was calculated.
The recorded results showed that, pectinase (PE) supplementation could not change growth
performance significantly, while values of breast pHu, drip loss % of thigh and total protein
(TP) of broiler meat were increased. Among ME levels, the reduction in ME of diet by 150
kcal/kg led to significant reduction of final body weight, while the reduction in ME by 100
kcal/kg led to significant reduction of abdominal fat %. Values of breast pHu, MDA and LDL
of broiler meat at 40 days of age decreased significantly by the reduction in ME at both level
(E100 and E150), while values of feed intake, feed conversion ratio, breast meat yield%,
thigh%, drum stick %, drip loss % of breast and TP of broiler meat were increased
significantly compared with STD values. Among all treatments the results showed
significantly effected on growth performance, carcass and meat quality parameters.
Calculation of feeding cost showed that STD group recorded the lowest value than other
treatments. The overall results of PE and ME indicated that both could not improve growth
performance parameters and feeding cost, while the quality of carcass and meat were
enhanced. Applying E100+PE diets could help producers to get acceptable marketing weight
with better carcass and meat quality.