A total number of 72 unsexed one-day-old broiler chicks were divided equally
into four groups {each of 18 chicks) and fed the starter recommended diet {1} during
the first week of age. Then , from 14 to 21 days of age , birds where allocated to three
tested energy-protein restriction diets representing 90%. 80% or 70% of starter
requirements (groups 2 ,3 and 4 ), compared to those ted 100% of the starter
requirements (control). Then, birds were switched again to the control starter diet [1).
All birds were fed grower and finisher diets from 22 to 37 and from 38 to 49 days of
age. respectively. Body weight, carcass characteristics. carcass analysis and serum
biochemical variables were taken at the end of experimental period (49 days of age}.
Results obtained can be abstracted as follow:
1-Body weight, relative weight values of carcass, liver, gizzard. kidney and heart did
not significantly affected by levels of energy-protein restriction used in the current
study.
2-Abdominal fat percentage was destined gradually and significantly (P<0.05) as feed
restriction levei increased.
3-Commercial carcass cuts {breast and thigh muscles) yielded a higher (P >005)
percentage distribution for breast portion and less (P>0.05) percentage distribution
for thighs than the control group.
4-Dry matter and ash content were nearly similar in all groups, while protein content
insignificantly increased with increasing energy-protein restriction levels. However,
ether extract of control group recorded the highest value compared to the others.
5-Serum total protein, albumin, globulin and uric acid content exhibited insignificant
values in treatment groups.
B-Total cholesterol, triglycerides, HDL and LDL levels in restricted feed broilers were
concomitant with those of body fat content and abdominal fat.
7-Semm glucose, T3 and T4 levels were insignificantly fluctuating in broilers fed
different feed restriction regimes.
It could be suggested that the effect of feed restriction in broilers at an early
age is more evident in lipid metabolism rather than protein metabolism, to obtain a
better understanding of their nutritionai and physiological responses.