Submitted to: Cow Country News
Publication Type: Popular Publication
Publication Acceptance Date: 7/31/2015
Publication Date: 8/6/2015
Citation: Aiken, G.E. 2015. From the Lab Bench: Plant secondary metabolites: The good and the bad. . Cow Country News. Pg. 68.
Interpretive Summary: Protein, carbohydrates, and lipids are plant primary metabolites that gain most of the attention in agriculture because they are required by both plants and animals for survival. Although plant secondary metabolites are used for a specific function, such as defense or improved tolerances to environmental stress, certain secondary metabolites in forage plants may enhance the performance and health of grazing animals. A metabolite from hops, ß acid, and one in clovers, biochanin a, have shown in laboratory studies with goat rumen fluid to both inhibit hyper-ammonia producing bacteria that breakdown protein in the rumen of grazing animals. As much as half of the protein consumed by grazing cattle can be degraded, which can be wasteful to the animal and cause the amino acids, the building blocks of proteins, to be modified to change the quality of the protein to one that falls short of meeting cattle requirements. Field studies are being conducted to determine if these secondary metabolites benefit animal performance, health, and well-being. These natural products could ultimately be accepted by food scientists and consumers as healthy and safe replacements for synthetic feed additives.
Technical Abstract: A column was written to discuss the negatives and positives of plant secondary metabolites. Primary metabolites are those metabolites that are required for survival, such as protein, carbohydrates, and lipids. Plant secondary metabolites are produced from primary metabolites and are not required for survival, but rather for a specific function, such as defense against environmental stresses. Secondary metabolites have commonly been associated with having negative effects on livestock, but we are starting to believe that certain secondary metabolites may enhance cattle growth, health, and well-being. Laboratory studies were conducted to determine the effects of certain secondary metabolites on rumen bacteria. Two secondary metabolites; beta acid (ß acid), which is produced by hops, and biochanin a, a metabolite produced by clover plants, most notably by red clover. Using rumen fluid from goats, Flythe treated the fluid with ß acid and demonstrated that it inhibited hyper-ammonia producing bacteria that can degrade as much as half of the ruminal protein. This microbial protein degradation is wasteful to the animal and causes the amino acids, the building blocks of proteins, to be modified to change the quality of the protein to one that falls short of meeting cattle requirements. These studies provided evidence that ß acid and biochanin can enhance the nutrition of cattle on forage-based diets.