Scientists have developed a new cattle-feed supplement, which dramatically boosts the content of unsaturated fatty acids over saturated fats in cows' milk.
The new supplement, based on naturally occurring proteins, could significantly improve the health value of milk, say the researchers from University of California. It also provides dairy processors with the ability to modify various food qualities, such as the spreadability of butter and the flavour of cheese.
The University of California funded the research and has filed both United States and international patent applications on the new feed supplement.
Milk, butter and meats have long been known to contain high levels of saturated fats, implicated in contributing to a higher risk of cardiovascular disease and high cholesterol in humans.
Cows commonly eat a variety of plant-based feeds, which contain varying amounts of vegetable oils. The vegetable oils are naturally high in unsaturated fats but these fats are transformed into saturated fats during the digestive process by microorganisms that live in the cow's rumen, part of the animal's stomach.
"Its been clear for decades that in order to reduce the saturated fats in milk and meat, we would have to protect the unsaturated dietary fats from these microbes in the rumen," said Ed DePeters, animal science professor at the university.
Unlike earlier methods to alter this process, the supplement devised by Rosenberg and DePeters relies on proteins that occur naturally in milk and other foods, without using any synthetic chemicals. By taking advantage of the unique properties of proteins, the researchers were able to form complexes between those proteins and lipids, which are high in unsaturated fatty acids. These complexes protect the lipids against modification by the microorgnisms that live in the rumen.
During feeding trials, the researchers mixed the supplement with the cows' normal feed. The study involved more than 750 cow-days, with more than 1500 milk samples analyzed. Within less than three days, they recorded as much as an 800 per cent increase in the proportion of specific unsaturated fatty acids, such as linolenic acid, in the cows' milk.
Although the supplement's effect has only been studied on the fatty-acid composition of milk, the researchers indicate that it might have similar benefits in reducing the level of saturated fats in meat.