Dietary fish oil impairs induction of gamma-interferon and delayed-type hypersensitivity during a systemic Salmonella enteritidis infection in rats.
Fish oil that is rich in n-3 polyunsaturated fatty acids markedly modulates immunological responses. Literature data indicate that the fish oil reduces cellular immunity and therefore impairs resistance to infections. We have investigated how dietary fish oil affects the immune response against a facultative intracellular pathogen, Salmonella enteritidis. Wistar rats were fed a diet containing 16% (w/w) of either fish oil or corn oil. After a 4-week adaptation period, rats were intraperitoneally challenged with 4 x 10(5) cfu of S. enteritidis. During the 14-day infection period, urine was collected on a daily basis. At days 2 and 14, eight rats per group were sacrificed. Urinary nitrate, used as a marker for NO production, was lower on a fish oil diet during days 3-8. At day 2, serum gamma-interferon was 48 +/- 7 pg/mL in the fish oil-fed rats compared with 162 +/- 52 pg/mL in the corn oil-fed rats. No effects were found on living salmonella in liver and spleen. At day 14, as markers of an impaired T-helper 1 (Th-1) response, a 38% lower delayed-type hypersensitivity responses and a lower salmonella-specific IgG2b were observed in the fish oil-fed rats. Although here dietary fish oil has affected only immune parameters, this impairment of the innate and Th-1-mediated immune response may have implications for the host resistance against other intracellular pathogens.
Snel
Johannes
J
NIZO Food Research, Division of Health & Safety, Ede, The Netherlands. Hans.snel@nizo.nl
Born
Leontine
L
van der Meer
Roelof
R
D000818:Animals; D005395:Fish Oils / Q000008:administration & dosage*; D006968:Hypersensitivity, Delayed / Q000517:prevention & control*; D007371:Interferon-gamma / Q000096:biosynthesis*; D008297:Male; D009569:Nitric Oxide / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D012481:Salmonella Infections, Animal / Q000276:immunology*; D012477:Salmonella enteritidis
D005395:Fish Oils; D009569:Nitric Oxide; D007371:Interferon-gamma