Dietary supplementation with xanthophyll as an effective way of identifying low-producing broiler breeder hens.
The relationship between dietary levels of xanthophyll, the degree of pigmentation in the hen, and egg production rate was studied in commercial broiler breeders (Anak 2000). In the first study, the degree of shank and beak coloration, measured with a 15-grade Roche yolk color fan, was determined in broiler breeder pullets until 34 wk of age. Although overall body coloration decreased with age following initiation of egg production, the degree of shank coloration was two- to threefold higher than that of the beak. In the second study, Roche Carophyll-red (canthaxanthin, 10%) was supplemented at levels of 0, 10, and 20 mg/kg in a corn and soybean diet containing xanthophyll, and given to hens for a period of 4 wk beginning at 55 wk of age. Increasing dietary canthaxanthin levels increased pigmentation of beak and egg yolk in a quadratic manner, whereas pigmentation increased linearly in the shank. The production rate was inversely related to the degree of shank and beak pigmentation. In a third study, the relationship between hen pigmentation (using Carophyll-red, 30 mg/kg of diet) and production rate was examined in a commercial flock of broiler breeder hens. Hens were sampled according to shank coloration (Grades 1 to 3) and egg production was monitored. The production rate of hens with high coloration was significantly lower (by approximately 33%) than the flock average. At peak production, shank pigmentation was too low to differentiate visually between degrees of coloration. Dietary supplementation of 5% corn gluten meal increased shank pigmentation and enabled efficient identification of the nonlaying hens.
Pinchasov
Y
Y
Department of Animal Science, Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot, Israel.
David
G
G
Zohari
S
S
D000821:Animal Feed; D000818:Animals; D001502:Beak / Q000187:drug effects; D001947:Breeding; D002645:Chickens / Q000502:physiology*; D004530:Egg Yolk / Q000187:drug effects*; D005260:Female; D005503:Food Additives; D006614:Hindlimb; D014975:Lutein; D010060:Ovulation / Q000502:physiology; D010858:Pigmentation / Q000187:drug effects*
D005503:Food Additives; D014975:Lutein