Antinutritionals of importance in animal nutrition

Antinutritionals of importance in animal nutrition

Antinutritional factors are substances that, even in a vestigial state, reduce or prevent the use of a nutritional element. These antinutritional factors are mostly secondary metabolites, which can be defined as compounds that do not have a recognized role in the maintenance of the fundamental vital processes of the plant that synthesize them, on the other hand, they play an important role in the interaction of the plant with its environment. Anti-nutritional factors are usually not viewed with “good eyes”. Although the term antinutritional factors refer only to the “bad” characteristics of these substances, it is worth remembering that they are not only responsible for generating adverse effects. On the contrary, practically all of them, if not all, are also capable of conferring possible beneficial effects on the animal organism. Some phenolic compounds that are most representative in animal feed are tannins, lignins, and gossypol. However, there are also saponins, mimosines, phytate, lecithins, protease inhibitors, and cyanogenic glycosides.


Tannins result from the secondary metabolism of plants. These are phenolic compounds with some solubility in water and the ability to form insoluble complexes with proteins, gelatins, and alkaloids. Tannins are of great ecological and economic interest.

Broiler chickens that ingest tannins may have low trypsin and alpha-amylase activity. However, it is worth remembering that tannins are an alternative to conventional antimicrobials, obtaining good results when applied correctly.


It is a yellowish phenolic pigment produced by the pigment glands found in the roots, aerial parts, and seeds of cotton. The thermal processing of the seeds causes gossypol to bind to the constituent amino acids of the cotton proteins, especially lysine. Conjugated, it has no toxicological importance. In free form, it brings major problems for animal nutrition.

Gossypol is more toxic to monogastrics and may reduce the oxygen-carrying capacity of the blood, resulting in short breaths and pulmonary edema. It also causes decreased growth rate, anorexia, weakness, apathy, and death if on prolonged consumption.

One of the main problems is linked to reproduction. Gossypol promotes reduced concentration, inhibition of motility, and increased sperm mortality.

Protease Inhibitors

They are proteins with wide distribution in the plant kingdom, capable of inhibiting the activities of trypsin, chymotrypsin, amylase, etc. Most studies are focused on trypsin, more precisely on soybeans.

It is attributed to ingestion of raw soy or derivatives without sufficient treatment, lower growth rate, excessive fecal loss of endogenous protein, among other harms.

In addition to those mentioned, we still have phytate, saponins, mimosines, lecithins, and non-starch polysaccharides – PNA’s.

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