Feed allowance-genotype interactions in broiler breeder hens.
Ad libitum feeding reduces livability and reproductive fitness in broiler breeder hens. Two genotypes, a standard (S) and an experimental dwarf broiler breeder (E), were fed ad libitum (SA and EA, respectively), restricted at 55% of ad libitum feed intake (intermediate restriction) from 6 to 15 wk of age (SI and EI, respectively), or restricted (SR and ER, respectively) to match a standard growth curve with a diluted mash feed (2,400 kcal/kg). The experiment was repeated at 2 locations (experiment 1 = 672 hens in pens from 0 to 40 wk; experiment 2 = 420 hens in pens and cages from 0 to 53 wk). Feed restriction reduced adult BW by 20% compared with ad libitum feeding, delayed sexual maturity by 2 to 4 wk, and improved livability. Hens fed the intermediate diet immediately compensated after 15 wk of age to reach BW, sexual maturity, and livability close to those of ad libitum-fed hens. The E genotype exhibited better tolerance to ad libitum feeding than the S genotype in all measured aspects. Average laying rate during the first 24 wk of lay was 66.4, 77.4, 69.9, 47.2, 57.9, and 72.4% for EA, EI, ER, SA, SI, and SR respectively in experiment 2. Egg abnormalities (double yolk, shell problems) decreased after the peak of lay but remained consistently higher for S compared with E, and for ad libitum and intermediate diets compared with the restricted diet. Yolk deposition rate was measured by a double dye technique. Duration of yolk rapid growth was 8.8 d in E and 9.3 d in S hens (P < 0.001), but this difference did not explain the observed variations in laying rate. The potential to increase feed allowances even with a diluted diet in broiler breeder hens requires adapted genotypes.
Bruggeman
V
V
Katholieke Universiteit Leuven, Kasteelpark Arenberg 30, Leuven B-3001, Belgium.
Onagbesan
O
O
Ragot
O
O
Metayer
S
S
Cassy
S
S
Favreau
F
F
Jego
Y
Y
Trevidy
J J
JJ
Tona
K
K
Williams
J
J
Decuypere
E
E
Picard
M
M
D000375:Aging; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002645:Chickens / Q000235:genetics*; D004032:Diet / Q000662:veterinary*; D004530:Egg Yolk / Q000502:physiology; D005260:Female; D005508:Food Deprivation; D005838:Genotype; D010058:Oviposition; D010063:Ovum / Q000502:physiology; D015430:Weight Gain