DIETARY UNSATURATED FATTY-ACIDS AFFECT ANTIBODY-RESPONSES AND GROWTH OF CHICKENS DIVERGENTLY SELECTED FOR HUMORAL RESPONSES TO SHEEP RED-BLOOD-CELLS

The effect of linoleic and linolenic acid on antibody (Ab) responses t o SRBC and BSA and on growth performance were studied in pullets of th ree genetically different laying lines. Pullers were fed one of three diets: a control diet, a linoleic acid-enriched diet, or a linolenic a cid enriched-diet. The linoleic and linolenic acid enriched-diets were the control diet enriched with either sunflower oil or linseed oil. T wo chicken lines divergently selected for high (H) and low (L) Ab resp onses to SRBC, and a randombred control (C) line were used. Total Ab r esponses to SRBC were not affected by diet, but in the H line a tenden cy for higher IgG titers to SRBC after primary immunization were found when birds were fed the linoleic diet. The humoral response to BSA wa s significantly affected by a line by immunization by diet interaction . In the H line birds, the linoleic diet significantly enhanced Ab tit ers to BSA as compared to the normal diet and linolenic acid-enriched diet. The linolenic acid-enriched diet sig significantly decreased Ab titers to BSA in the C line birds. No dietary effects on the titer to BSA were found in the L line birds. During the first 3 wk of life, the linolenic acid-enriched diet resulted in reduced BW gain of H line bi rds. After that period, no effects of diet on BW gain was found. It is concluded that modulation of Ab responses of poultry to T cell-depend ent antigens by essential fatty acids is affected by genotype. The rel ationship between magnitude of Ab responsiveness, BW, and essential fa tty acids is discussed.