J. Yaissle et Ms. Lilburn, EFFECTS OF DIETARY-PROTEIN AND STRAIN ON THE GROWTH OF BROILER BREEDER PULLETS FROM ZERO TO 5 WEEKS OF AGE, Poultry science, 77(11), 1998, pp. 1613-1619
In a series of four experiments, the effects of differences in dietary
protein intake on BW, skeletal growth and the weight of the Pectorali
s major muscle was studied in Hubbard Standard and Hubbard Hi-Y broile
r breeder pullets. In Experiment 1, pullets were fed diets with either
15, 17, or 19% CP from 1 to 21 d. There was a linear increase in BW g
ain and feed consumption with each increase in CP and Hubbard Standard
pullets consumed significantly more feed than Hubbard Hi-Y pullets. F
rom 21 to 34 d, pullets were subjected to feed restriction every day (
ED) or every-other-day (EOD). On Day 35, pullets were given ad libitum
access to feed and ED-restricted pullets consumed significantly more
feed than EOD-restricted pullets through 3.5 h postfeeding. In Experim
ent (Exp.) 2, pullets were fed the 19% CP diet for approximately 14 d
(300 g) or 20 d (600 g) before being switched to the 15% CP diet. In E
xperiment 3, the 19% CP diet was fed for exactly 7 or 21 d before swit
ching to the 15% CP diet. Ln all experiments, Hubbard Standard pullets
weighed significantly more than Hubbard Hi-Y pullets and had increase
d overall skeletal growth. When the pullets from both strains were res
tricted to only 380 g BW at 28 d, (Exp. 3) the longer period of protei
n intake significantly enhanced breast muscle weight but there were no
significant strain differences. When BW at 28 d was increased to 480
g, (Exp. 2), dietary protein and strain differences were observed.