Breeder age and pre-placement feed are factors that can affect broiler performance during grow out. This study evaluated the effects of breeder age (29 and 55 weeks old) on IgY transference to egg yolk in addition to the effects of breeder age (29 and 55 weeks old) and pre-placement feed (with or without), in a factorial arrangement, on IgY concentration in chick serum. Forty-eight eggs were collected from a breeder flock and considered the experimental units. Eighteen chicks from each breeder age were randomly selected to determine IgY at pulling. After 48 h of placement, old breeders had greater egg weight and yolk weight (p ≤ 0.05) than the young ones. Breeder age (p > 0.05) had no effect on IgY concentration of egg yolk. Breeder age (p > 0.05) had no effect on IgY concentration of chick serum at pulling. There was no interaction (p > 0.05) between breeder age and pre-placement feed for IgY concentration of chick serum at housing. There was also no effect of breeder age or pre-placement feed during placement time (48 h) on IgY concentration of chick serum at housing (p > 0.05). In conclusion, 48 h of fasting had no effect on IgY concentration in chick serum despite breeder age. It appears that the immunoglobulins from the residual yolk sac are not used as a protein source during the period between hatching and housing.
Keywords: chick serum; fasting; immunoglobulin; old breeders; placement time; young breeders.
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