Maternal dietary ratio of linoleic acid to alpha-linolenic acid affects the passive immunity of hatching chicks

The objective of the current study was to examine the effect of dietary ratio of linoleic acid (LA) to alpha-linolenic acid (LNA) on the humoral immune response in laying hens and further on the passive immunity of their progeny. Thirty-two Single Comb White Leghorn laying hens, 24 wk of age, were randomly assigned to 1 of 4 diets that had LA-to-LNA ratios of 0.8, 5.4, 12.5, and 27.7, respectively, by changing the proportions of sunflower and linseed oils. After 5 wk on the experimental diets, hens were immunized intramuscularly with 1 mg of BSA, followed by 2 boosters 2 and 6 wk later. Serum and egg yolk were obtained weekly from 0 to 6 wk following the first injection of BSA. One week after the second booster, fertile eggs were collected and incubated. The sera of 11-d-old embryos and hatchlings were collected. All serum samples were stored at -20 degrees C before analysis. The results showed that dietary LA-to-LNA ratio had no effect on the total IgG and BSA-specific antibody IgG concentrations in the serum or egg yolk of laying hens. Hatchlings from hens fed the diet containing the LA-to-LNA ratio of 12.4 showed lower (P < 0.05) BSA-specific IgG titer in the serum than those from hens given the diet containing LA-to-LNA ratio of 0.8. A lower (P < 0.05) total IgG concentration was observed in hatchlings from hens fed the diet containing LA-to-LNA ratio of 12.4 compared with those from hens fed diets containing 0.8 and 5.4 of LA-to-LNA ratios. It is suggested that the dietary ratio of LA to LNA has no effect on laying hen humoral response but affects the passive immunity of hatching chicks.