Dietary polyunsaturated fatty acid effects on immune cells of the porcine lung

The effects of various dietary polyunsaturated fatty acids (PUFAs) on the function of immune cells of the porcine lung was studied. Groups of six pigs were fed diets containing 10.5% corn oil [CO; enriched in linoleic acid (18:2, n-6)], linseed oil (LO; enriched in alpha-linolenic acid (18:3, n-3)], menhaden oil (MO; enriched in eicosapentaenoic (20:5; n-3) and docosahexaenoic (22:6; n-3) acids], linseed + corn oil (1:1; LC), and menhaden + corn oil (1:1; MC) for 28-30 days. Basal levels of alveolar macrophage (m phi) tumor necrosis factor-alpha (TNF-alpha) production were higher (P < .05) for LC- and MC-fed pigs than for CO- and LO-fed pigs. Lipopolysaccharide (LPS)-stimulated LC and MC m phi s produced more TNF than m phi s from pigs fed CO, LO, and MO diets. Macrophages from pigs receiving the CO and LC diets had higher (P < .05) levels of leucine aminopeptidase than m phi s from the other dietary groups. Lipopolysaccharide did not increase m phi nitrite production over basal levels except in the MO diet group. However, LPS-stimulated m phi s from the CO, MO, and LC dietary groups produced more nitrite than m phi s from MC-fed pigs. Alveolar lymphocytes from pigs receiving the MC diet produced more T cell growth factors than LO and MO m phi s. Alveolar m phi s from the different dietary groups did not differ in their capacity for non-immune-mediated phagocytosis of fluorescent latex beads. These results indicate that dietary PUFAs can modulate some functions of porcine alveolar immune cells and that this may prove significant for host response to respiratory disease agents.