Distribution of fatty acids in the plasma lipids of herbivores grazing pasture: a species comparison.

The research considers how fatty acids are allocated in the plasma lipids of different herbivores that graze grass. It was observed that cows have different fatty acid ratio in their plasma lipids compared to other herbivores studied.

Research Details

• The research examined the distribution of fatty acids in the plasma lipids of various herbivores when they graze on pasture. These herbivores included cows, sheep, goats, horses, donkeys, llamas, wallabies, and rabbits. There was a focus on the occurrence of certain types of fatty acids, namely polyunsaturated fatty acids, in their plasma.
• The researchers observed a correlation in the content of polyunsaturated fatty acids between two plasma components – cholesteryl esters and lecithin. This relationship was considered to be linear, meaning that the value of one would predictably correspond to the value of the other.
• Specifically, they found that for every one unit of cholesteryl ester C18:2 acid, there was one unit of the same fatty acid in the beta position of the plasma lecithin, and the same 1:1 ratio was found for C18:3 acid. The exception to this trend was in cows, in which for every two units of cholesteryl ester C18:3 acid, there was one unit of the same fatty acid in the beta position of lecithin.
• Considering this tendency observed in cows, the researchers suggested that in cows the enzyme plasma lecithin-cholesterol acyltransferase (which acts in the process of transferring fatty acids such as the C18:3 acid) has a high specificity for C18:3 acid.

Implications of the Research

• As referenced in the introduction, during a previous research on plasma lipids of ruminant animals, the researchers noted that cholesteryl esters in cows contained a higher percentage of C18:3 fatty acids than those in sheep and goats (Leat, 1966). This information, in combination with the new findings on the different fatty acid ratio in cows, may suggest the role of dietary lipid in shaping this difference.
• Although the researchers used a variety of herbivores for their study, they also mentioned that the diets of these animals were not well-defined, which raises the possibility that diet could be an important factor in these differences in fatty acid distribution. This consideration sets the stage for future research in identifying whether and how dietary differences among various herbivores might affect the distribution of fatty acids in plasma lipids.