Phospholipid fatty acids of brain and liver are modified by alpha-tocopherol and dietary fat in growing chicks
Fuhrmann, H.; Sallmann, H.P.
British Journal of Nutrition 76(1): 109-122
ISSN/ISBN: 0007-1145 PMID: 8774221 Accession: 009188009
Dietary fatty acids modify phospholipid fatty acids in brain and liver of growing chickens post-hatching. The effect of vitamin E deficiency on this process is unknown and may be relevant to the pathogenesis of chick nutritional encephalomalacia (NE). Therefore laying hens received a diet low in vitamin E (10 mg alpha-tocopherol/kg feed). Resulting chicks were assigned to nine dietary groups each fed with either oleic (18: In-9, 58 g/kg), linoleic (18:2n-6, 57 g/kg) or linolenic (18:3n-3, 56 g/kg) acid together with 5, 25 or 125 mg alpha-tocopherol/kg feed. NE affecting the cerebellum only occurred in the group given linoleic acid and 5 mg alpha-tocopherol/kg. in 1-d-old chicks and after 1 and 2 weeks the phospholipid fatty acid composition of liver, cerebrum and cerebellum (additionally after 3 weeks) was determined. The feed fatty acids were incorporated into the liver very efficiently during the first week of fife. Unsaturation of liver membranes decreased in the order dietary linolenic gt linoleic gt oleic acid. In liver, also, the effect of alpha-tocopherol supplementation on phospholipid fatty acids was most pronounced. The unsaturation index increased during deficiency, whereas n-9 fatty acids decreased. In the chicken brain the alterations were delayed and less distinct. The cerebellum phospholipids were rich in n-9 fatty acids and as a whole more saturated in comparison with the cerebrum. Cerebellar unsaturation increased when linolenic or linoleic acid was given. However, NE-producing dietary conditions were not accompanied by specific alterations in cerebellar phospholipid fatty acids due to the alpha-tocopherol content of the diet. Rather the alterations of membrane fatty acids in the liver seem to play a role in the pathogenesis of NE.