Insights into the role of major bioactive dietary nutrients in lamb meat quality: a review

Feed supplementation with alpha-linolenic acid (ALA) and linoleic acid (LA) increases their content in muscle, ALA increases n-3 polyunsaturated fatty acids and decrease n-6/n-3 ratio in muscle, and LA increases rumenic acid. However, high LA supplementation may have negative effects on lambs' lipid oxidative stability of meat. When the sources of ALA and LA are fed as fresh forage, the negative effects are counterbalanced by the presence of other bioactive compounds, as vitamin E (mainly alpha-tocopherol) and polyphenols, which delay the lipid oxidation in meat. There is a wide consensus on the capability of vitamin E delaying lipid oxidation on lamb meat, and its feed content should be adjusted to the length of supplementation. A high dietary inclusion of proanthocyanidins, phenolic compounds and terpenes reduce the lipid oxidation in muscle and may improve the shelf life of meat, probably as a result of a combined effect with dietary vitamin E. However, the recommended dietary inclusion levels depend on the polyphenol type and concentration and antioxidant capacity of the feedstuffs, which cannot be compared easily because no routine analytical grading methods are yet available. Unless phenolic compounds content in dietary ingredients/supplements for lambs are reported, no specific association with animal physiology responses may be established.

Automated summary

Feeding lamb with feed supplemented with alpha-linolenic acid (ALA) and linoleic acid (LA) can increase the fatty acid content in muscle, but high LA supplementation may negatively affect lipid oxidative stability. The presence of other bioactive compounds in fresh forage, such as vitamin E and polyphenols, can counterbalance the negative effects and delay lipid oxidation. The recommended inclusion levels of phenolic compounds in feed depend on type, concentration, and antioxidant capacity.