High dietary 18:3n-3 increases the 18:3n-3 but not the 22:6n-3 content in the whole body, brain, skin, epididymal fat pads, and muscles of suckling rat pups

Abstract

The objective of this study was to test the hypothesis that increasing maternal dietary 18:3n-3 by decreasing the 18:2n-6/18:3n-3 ratio will increase the 18:3n-3 and 22:6n-3 content of the whole body, liver, skin (epidermis, dermis, and subcutaneous tissue), epididymal fat pads, and muscles (arms and legs) of 2-wk-old rat pups. Sprague-Dawley dams at parturition were fed semipurified diets containing either a low (18:2n-6 to 18:3n-3 ratio of 24.7:1) or a high (1 8:2n-6 to 18:3n-3 ratio of 1.0:1) 18:3n-3 fatty acid content. During the first 2 wk of life, rat pups received only their dams' milk. Fatty acid composition of the pups' stomach contents (dams' milk), whole body, brain, liver, skin, epididymal fat pads, and muscles was determined. The stomach fatty acid composition of 18:3n-3 reflected the dams' diet. The content of 18:3n-3 in whole body, brain, liver, skin, epididymal fat pads, and muscles was significantly (P< 0.05) greater in rat pups fed the high compared with the low 18:3n-3 fatty acid diet. The 22:6n-3 content of the whole body, brain, skin, epididymal fat pads, and muscles was not quantitatively different in rat pups fed either the low or high 18:3n-3 fatty acid diet. The 20:5n-3 and 22:5n-3 content of the whole body, skin, and epididymal fat pads was significantly increased in rat pups fed the high compared with the low 18:3n-3 fatty acid diet. High content of 18:3n-3 was found in the skin of rat pups fed either a low or high 18:3n-3 fatty acid diet. These findings demonstrate that high maternal dietary 18:3n-3 significantly increases the 18:3n-3 but not the 22:6n-3 content of the whole body, brain, skin, epididymal fat pads, and muscles with approximately 39 and 41% of the whole body 18:3n-3 content being deposited in the skin of suckling rat pups fed either the low or high 18:3n-3 diet, respectively.