EFFECTS OF EGG AND YOLK WEIGHTS ON YOLK ANTIBODY (IGY) PRODUCTION IN LAYING CHICKENS

Twenty 35-wk-old chickens, including 10 Single Comb White Leghorn (SCW L) and 10 Rhode Island Red (RIR) hens, were used to examine the effect s of egg and yolk weights on egg yolk antibody (IgY) production in the two strains of chickens immunized with BSA. The SCWL chickens had a g reater (P < 0.01) percentage hen-day production and greater egg and yo lk weights than did the RIR chickens. However, the anti-BSA antibody a ctivities determined by ELISA in the serum and the egg yolk were simil ar (P > 0.05) between the SCWL and RIR chickens. Similarities between the two strains of hens were also observed in protein and total IgY co ntents (expressed as the percentage of wet weight of yolk) and the per centage of BSA-specific antibody in the total IgY. It was concluded th at both the SCWL and RIR chickens immunized with BSA can produce egg y olk IgY containing similar proportions of BSA-specific antibodies. The refore, the egg yolk weight and the percentage hen-day production, bot h of which are greater in the SCWL hens, are considered to be importan t factors for the efficient production of IgY.