The effect of diet supplemented with vegetable oils and/or monensin on the vaccenic acid production in continuous culture fermenters

Studies have shown that supplementing ruminant diets with vegetable oils modulated the rumen biohydrogenation and increased polyunsaturated fatty acid in their products. These positive values are often accompanied by a marginal loss of supplemented unsaturated fatty acids and rise in the concentrations of saturated fatty acids. This study were carried out mainly to investigate the effect of supplementing diets with sunflower oil, olive oil with or without monensin on the production and accumulation of vaccenic acid(VA) in continuous culture fermenters as a long term in vitro rumen simulation technique.Eight dual-flow continuous culture fermenters were used in an 8 replication experiment lasted 10 days each(first 7 days for adaptation and last 3 days for samples collection). Supplementing diets with plant oils and monensin in the present experiment increased VA and conjugated linoleic acids(P > 0.05) in ruminal cultures. The results suggest that supplementing diets with both olive oil and sunflower oil and monensin increased VA accumulation compared to plant oils supplemented alone without affecting the rumen dry matter and organic matter digestibility.

The scope for manipulating the polyunsaturated fatty acid content of beef:a review

Since 1950, links between intake of saturated fatty acids and heart disease have led to recommendations to limit consumption of saturated fatty acid-rich foods, including beef. Over this time, changes in food consumption patterns in several countries including Canada and the USA have not led to improvements in health. Instead, the incidence of obesity, type II diabetes and associated diseases have reached epidemic proportions owing in part to replacement of dietary fat with refined carbohydrates. Despite the content of saturated fatty acids in beef, it is also rich in heart healthy cis-monounsaturated fatty acids, and can be an important source of long-chain omega-3（n-3） fatty acids in populations where little or no oily fish is consumed. Beef also contains polyunsaturated fatty acid biohydrogenation products,including vaccenic and rumenic acids, which have been shown to have anticarcinogenic and hypolipidemic properties in cell culture and animal models. Beef can be enriched with these beneficial fatty acids through manipulation of beef cattle diets, which is now more important than ever because of increasing public understanding of the relationships between diet and health. The present review examines recommendations for beef in human diets, the need to recognize the complex nature of beef fat, how cattle diets and management can alter the fatty acid composition of beef, and to what extent content claims are currently possible for beef fatty acids.

Fatty Acids and Triglycerides Composition in Uruguayan Cow, Sheep and Goat Cheeses

Adverse health consequences are associated with consumption of so-called trans fatty acids （FAs） generated during chemical hydrogenation processes. Naturally-occurring trans fats, including trans vaccenic acid （TVA） derived from a conjugated isomer of linoleic acid （18：2 cis-9, trans-11）, （CLA） in contrast, are recognized as having potentially beneficial effects on human health. These natural trans FAs are found in fat from dairy products and meat of ruminants, and have distinct effects compared with trans FAs industrially produced. The lipid composition of cheeses depends on the milk used. In this work was determined CLA and TVA content in milk fat of sheep and cow to be 1.4% and 3.2%, respectively, and from goat, 0.7% and 1.8%. Also, differences in CLA and TVA content were found in fat extracted from samples of the same cheese type made from cow＇s milk from the same company but with different production dates during a year. The levels of CLA and TVA found in Uruguayan cheeses were generally higher than levels reported in previous studies with comparable cheeses produced in other countries. Milk fat is well-known to confer specific properties to foods. This in turn will affect the rheology and sensory attributes as food. For this reason, it is of interest to determine the triglyceride （TAG） composition in milk-derived foods. Results show that there are characteristic differences in the TAG composition of the different cheeses. We found minimal differences between cheeses from goat and sheep but found distinct characteristics for TAGs from cow milk-derived cheese.