Abstract:
Two experiments were carried out to evaluate the effects of feed restriction during the
starter stage and lysine supplementation during realimentation on productivity and
carcass characteristics of Ross 308 broiler chickens. In the first experiment, the effects of
level and period of feed restriction during the starter period on subsequent productivity
were evaluated. A 2 (male and female chickens) x 3 (feeding levels, ad libitum and 75%
and 50% of ad libitum) x 3 (restriction periods of 5, 7 and 9 days), factorial arrangement
in a Completely Randomized Design was used. The effects interactions were not included
in the results because earlier analyses including all the interactions showed that they were
not important. Level and period of feed restriction during the starter stage had an effect
(P<0.05) on live weight of the chickens at 21 days of age. However, female and male
chickens had similar live weights at 21 days of age. Chickens on 75% ad libitum feeding
attained complete live weight compensation at the age of 42 days. However, chickens on
50% ad libitum feeding did not ‘catch-up’ with those on ad libitum feeding. Differences
due to the period of feed restriction during the starter stage were maintained up to the age
of 42 days. Male chickens had higher (P<0.05) live weights at 42 days of age. Abdominal
fat pad was not affected (P>0.05) by level and period of feed restriction and sex of
chickens at 42 days of age.
The second experiment evaluated the effects of feed restriction during the starter stage
(14 to 21 days) and levels of lysine supplementation during realimentation (21 to 42
days) on productivity and carcass characteristics of male and female chickens. Feed
v
restriction affected (P<0.05) live weight of chickens at the age of 21 days and males were
heavier (P<0.05) than females at the same age. Chickens on 75% ad libitum feeding
attained complete compensation in live weight while those on 50% ad libitum feeding did
not. Lysine supplementation during realimentation had no effects (P>0.05) on live weight
and carcass characteristics of the chickens at 42 days of age. Male chickens attained
higher (P<0.05) live weights than female chickens at 42 days of age.
