IMMUNE MODULATION BY ALTERED NUTRIENT METABOLISM - NUTRITIONAL CONTROL OF IMMUNE-INDUCED GROWTH DEPRESSION

The ability of conjugated isomers of linoleic acid (CLA) to prevent re duced growth rate following endotoxin (lipopolysaccharide, LPS) inject ion was studied in two chick trials and one rat trial. Chicks (10 per treatment) were fed a com and soybean meal-based diet with or without .5% CLA. At 21 days of age, chicks were weighed and injected i.p. with 1 mg/kg BW Escherichia coli LPS and sterile PBS. Body weights were ag ain determined 24 h later. Antibody responses to SRBC were also determ ined. Rats fed .5% stearic acid or CLA for 4 wk (seven per treatment) were also injected with LPS, and BW change over a 24-h postinjection p eriod was determined. Antibody responses to BSA, phytohemagglutinin fo ot pad swelling, and phagocytosis of elicited peritoneal macrophages w ere also determined. The CLA had no adverse effects on any immune vari ables measured in the chicks and rats. The CLA enhanced the phytohemag glutinin response and macrophage phagocytosis in rats. Chicks fed CLA and injected with LPS continued to grow, whereas those not fed CLA eit her failed to grow or lost weight following LPS injection. Both contro l and CLA-fed rats lost weight over the 24-h period after LPS injectio n; however, the loss of weight in rats fed CLA was only half of the we ight loss of the control rats. Thus, CLA is effective in preventing th e catabolic effects of immune stimulation.