Abstract
There is increased competition in the protein market with the entrance of cell-based and plant-based products. Consumers issues with consumption of red meat typically center around saturated (SFA) fatty acid content and environmental impacts associated with production. Nutritional system used for finishing beef and lamb alters fatty acid composition of the meat product. Forages and grasses that are utilized in a grass-fed finishing system increases the animal’s intake of a-linolenic acid (C18:3 n-3), the main fatty acid present in plants (57%) that can be converted to eicosapentaenoic (C20:5 n-3), docosapentaenoic (C22:5 n-3) and docosahexaenoic (C22:6 n-3) acids in animal tissues. Grain-fed finishing systems increases the animal’s intake of linoleic acid (C18:2 n-6), the main fatty acid present in corn grain (57%), that can be converted to arachidonic acid (C20:4 n-6) and docosatetraenoic acid (C22:4 n-6) in animal tissues. Biohydrogenation of polyunsaturated fatty acids (PUFA) is extensive in the rumen (> 80% of dietary PUFA) and rumen protected supplements are needed to enhance PUFA content of ruminant meat products. Saturated (SFA) and monounsaturated (MUFA) fatty acids are the majority (>75% of total fatty acids) of fatty acids present in ruminant meat products. Therefore, finding approaches to attain greater desaturation of palmitic and stearic acids to their MUFA products, palmitoleic and oleic acids, would be most beneficial. The content of oleic acid and MUFA in beef is highly heritable and some breeds have high levels of MUFA. Stearoyl-CoA desaturase (SCD1) is the rate limiting enzyme in the production of MUFA. More research is needed to find ways of altering SCD1 expression in meat animal tissues to enhance MUFA and lower SFA content.
STUDIES ON THE FATTY ACID OXIDIZING SYSTEM OF ANIMAL TISSUES