NEONATAL IMMUNE-RESPONSE AND GROWTH-PERFORMANCE OF CHICKS HATCHED FROM SINGLE COMB WHITE LEGHORN BREEDERS FED DIETS SUPPLEMENTED WITH BETA-CAROTENE, CANTHAXANTHIN, OR LUTEIN

Forty Single Comb White Leghorn (SCWL) hens and 8 SCWL cocks were randomly divided into four treatment groups. Each group was fed a diet containing .02% beta-carotene, canthaxanthin, lutein, or basal control. After 20 d of feeding, eggs were collected daily from each experimental group for incubation. Two different hatches were set and chicks from each hatch were used for one of two different experiments. In both experiments, 24 chicks per treatment were vaccinated against Newcastle disease virus at 1 d of age and raised for 5 wk on a basal diet. In the second experiment, birds were revaccinated at 3 wk of age. In both experiments, at the end of 5 wk birds were killed and bursa of Fabricius, liver, and spleen were collected. For both experiments, there were no differences in antibody titers, weight gain, feed conversion ratio, and relative bursa weights of chicks. However in the second experiment, birds hatched from breeders fed lutein had significantly lower relative liver weights than chicks of the other treatments, whereas birds hatched from the breeders fed P-carotene and canthaxanthin had significantly lower spleen weights than the control. These experiments suggest that carotenoids may not be effective in increasing neonatal immune response when they supplement practical breeder diets.