Dietary Fatty Acid Composition Impacts the Fatty Acid Profiles of Different Regions of the Bovine Brain

SIMPLE SUMMARY: The fatty acid composition of the mammalian brains varies by functional region, development, sex, and diet. In the current study, diets for growing female and castrated male bovines were supplemented with the calcium salts of palm or fish oil for 220 days. The cattle had unrestricted access to the supplements. At slaughter, the brains were removed from the cranium and blocked to the functional region. Analysis of the fatty acid content of the brain revealed they had similar fatty acid contents to other species including rodents and wild ungulates. Although diet differences across the regions were small, cattle supplemented with fish oil had greater contents of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), with arachidonic acid levels being greater in palm-oil-supplemented cattle. Fatty acid contents across regions were similar to what has been reported for other species, and it suggests that a conserved lipid metabolism creates a uniform brain fatty acid profile. ABSTRACT: Fatty acid composition across functional brain regions was determined in bovine brains collected from cattle that were provided supplements of calcium salts containing either palm or fish oil. The Angus cattle were divided into two groups, with one group offered the supplement of calcium salts of palm oil and the other offered the calcium salts of fish oil (n = 5 females and n = 5 males/supplement) for 220 days. These supplements to the basal forage diet were provided ad libitum as a suspension in dried molasses. The fish oil exclusively provided eicosapentaenoic acid (EPA, C20:5 n-3) and docosahexaenoic acid (DHA, C22:6 n-3). The functional regions were dissected from the entire brains following commercial harvest. While the cattle provided diets supplemented with the calcium salts of palm oil had increased (p < 0.01) liver concentrations of C18:1 n-9, C18:2 n-6, and arachidonic acid, the fish-oil-supplemented cattle had greater (p < 0.01) concentrations of liver EPA, DHA, and C18:3 n-3. In the brain, DHA was the most abundant polyunsaturated fatty acid. In the amygdala, pons, frontal lobe, internal capsule, and sensory cortex, DHA concentrations were greater (p < 0.05) in the brains of the cattle fed fish oil. Differences among the supplements were small, indicating that brain DHA content is resistant to dietary change. Arachidonic acid and C22:4 n-6 concentrations were greater across the regions for the palm-oil-supplemented cattle. EPA and C22:5 n-3 concentrations were low, but they were greater across the regions for the cattle fed fish oil. The effects of sex were inconsistent. The fatty acid profiles of the brain regions differed by diet, but they were similar to the contents reported for other species.