Abstract • 6
Arachidonic acid (AA) is the third most abundant polyunsaturated fatty acid (PUFA) in colostrum (around 1% total FA). AA is the precursor of prostaglandins, thus its functional role in defense mechanisms may be relevant for extrauterine life. We have investigated the concentrations of the two essential PUFA (linoleic acid, LA, and α-linoleic acid, LnA), AA and its direct metabolic precursor, di-homo-γ-linolenic acid, DHGLA, in plasma and colostrum of lactating mothers. Pooled colostrum from all the feedings over 24 hours was collected during the first day of lactation from 21 mothers after delivery of full-term infants. The maternal plasma samples were collected after an overnight fasting. Fatty acid (FA) methyl esters were analyzed by capillary gas-chromatography. Statistics: Spearman's r. FA % values (mean, coefficient of variation) were respectively: for plasma, LA: 26, 13%; LnA: 0.41, 28%; DHGLA: 1.5, 18%, AA: 5.9, 22%; for colostrum, LA 11, 17%; LnA 0.67, 35%; DHGLA 0.65, 25%; AA 0.91, 12%. Concerning the relationships between PUFA in plasma and colostrum, r values were 0.37 for LA (P=0.09), 0.80 for LnA (P<0.001), 0.39 for DHGLA (P=0.07) and 0.15 for AA (P=0.49). AA in colostrum has a limited variability and seems to depend less on maternal concentrations compared to other PUFA. Regulatory mechanisms in the mammary gland may act to preserve AA in colostrum.
