The effects of diets supplemented with increasing ratios of n-6 to n-3 polyunsaturated fatty acids on leukotriene B synthesis in dog skin and neutrophils were evaluated.

Thirty Beagles were conditioned for 2 months on a diet with an n-6 to n-3 fatty acid ratio of 28:1. Experimental diets, containing n-6 to n-3 ratios of 5:1, 10:1, 25:1, 50:1 and 100:1 (six dogs/group), were fed for 12 weeks.

At the end of the 2 month control diet period, and again at 6 and 12 weeks of treatment feeding, leukotriene B4 and leukotriene B5 were quantitated in skin and neutrophils.

Neutrophils from dogs fed the 5:1 and 10:1 diets synthesized 30–33 per cent less leukotriene B4 (P < 0.05) and 370–500 per cent greater leukotriene B5 (P < 0.05) at 6 and 12 weeks, but had no change in the release of superoxide anions during respiratory burst.

Lipopolysaccharide-stimu-lated dog skin synthesized 48–62 per cent less leukotriene B4 (P < 0.05) and 48–79 per cent more leukotriene B5 (P <0.05) at 12 weeks.