Fatty acid profile of colostrum and milk of ewes supplemented with fish meal and the subsequent plasma fatty acid status of their lambs.

The objectives of the current study were to 1) determine whether a fish-meal-supplemented diet fed to ewes during late gestation and early lactation would increase the proportion of docosahexaenoic acid (22:6n-3) in colostrum and milk and 2) examine the subsequent effect on the plasma fatty acid profile of nursing lambs. Eight gestating ewes (Rideau-Arcott; 97 +/- 5 kg of initial BW; 100 d of gestation) were used in a completely randomized design. Ewes were individually housed and fed a control diet (supplemented with soybean meal) or a fish-meal-supplemented diet for 6 wk before lambing and throughout 7 wk of lactation. Colostrum at d 0 and milk samples at d 36 and 49 of lactation were collected. Blood samples were collected from lambs throughout the preweaning period (at 0, 36, and 49 d of age). Fatty acids of the samples were analyzed by GLC. The ewes fed the fish-meal-supplemented diet had greater (P <or= 0.013) percentages (g/100 g of total fatty acids) of eicosapentaenoic acid (20:5n-3, 0.16 vs. 0.08), docosahexaenoic acid (0.33 vs. 0.09), total n-3-PUFA (2.72 vs. 1.91), total CLA (0.83 vs. 0.64), and total very long chain n-3-PUFA (>C18, 0.70 vs. 0.38), in colostrum and milk compared with the ewes fed the control diet. However, these fatty acids, excluding total n-3-PUFA, did not change over time, nor was there an interaction between diet and time. The percentage of total SFA was increased (P = 0.012) linearly over time without having any diet effect. The ratio of n-6-PUFA to n-3-PUFA in colostrum and milk from the control group was greater (P = 0.003) than that of the fish-meal-supplemented group. This ratio was decreased over time (P = 0.001). At birth (d 0), lambs born to the fish-meal-supplemented ewes had greater (P = 0.001) plasma concentrations (g/100 g of total fatty acids) of eicosapentaenoic acid, docosahexaenoic acid, and total very long chain n-3-PUFA than the lambs born to the control ewes. The concentrations of these fatty acids were further increased over time (P = 0.001) for the lambs nursing ewes fed the fish-meal-supplemented diet. The present findings suggest that the concentrations of docosahexaenoic acid in ewe colostrum and milk can be enhanced through diet supplementation with fish meal. The docosahexaenoic acid status of their suckling lambs can also be further enhanced, and this may contribute to improve neural tissue development and overall performance of suckling lambs.