Recent media reports have brought to light a subject that has been the subject of research and concern in the field of bird feeding for some time: Biogenic Amines (AB). There is an argument even defending the need for standardization regarding the maximum levels of these substances in the feed ingredients, especially those of animal origin.

But what is the importance of AB in the production of chickens and eggs? Based on the scientific literature, would AB really be able to cause damage to birds considering the usual levels of inclusion of ingredients of animal origin in feed? What is the argument for decision making and from what concentration would this be a real concern?

Does it make sense to be concerned about consumer safety from the consumption of chicken meat or eggs from poultry that have been fed a diet containing AB? These questions moved the authors to prepare this brief text. The intention is to contribute to the consumer chains of poultry production through objective analysis and recommendations for practical application.

Characterization and biological role of biogenic amines

Biogenic amines (AB) are low molecular weight, nitrogenous organic compounds common to all living things. Some of these substances are synthesized by the own animal organism for its corporal metabolism, where they fulfill essential role to the life promoting the synthesis of DNA, RNA and proteins and the stabilization of ribosomes.

They can still present endogenous antioxidant action and increase of amino acids absorption by the cells. The AB can also be synthesized by the bacteria through the process of decarboxylation of aminoacids or by the amination and transamination of aldehydes and ketones in the decomposition process. Common presence in animal feed and human food ingredients.

Depending on the amino acid that originates the AB, different compounds are obtained, such as cadaverine (from the amino acid lysine), histamine (histidine), putrescine and agmatin (arginine), spermine and spermidine (ornithine), tryptamine (tryptophan), tyramine (tyrosine) and phenyltilamine (phenylalanine).

AB are classified according to their chemical structure into aliphatic (putrescine, cadaverine, spermidine and spermine), aromatic (tyramine and phenyltylamine) and heterocyclic (histamine and tryptamine). The polyamines (spermidine and spermine) present some particularities due to the presence in practically all types of cells and for the role as essential components in the synthesis of macromolecules and in the cellular multiplication.

It is not the aim of this text to go into the function of AB in depth, but the importance of these substances in the body can be exemplified by spermidine. This was the subject of a recent publication in Science Magazine (Madeo et. al, 2018) that focused on the anti-aging effects of spermidine due to its ability to induce autophagy for cell protection.

According to the authors, spermidine would be involved in the degradation of damaged and potentially toxic organelles and protein aggregates that pose a risk to the cell. Thus, the authors report improvements in mental capacity in animal models from the ingestion of spermidine.

Also in the case of polyamines, studies in humans have shown that high levels of spermine and spermidine from breast milk can protect infants from allergies (Dandrifosse et al., 2000). According to observations made with rats, the action is possibly a consequence of lower intestinal permeability to antigenic macromolecules, as well as the induction of the maturation of the immune system associated with the small intestine.

These findings have proven to be important for the human area, where the use of breast milk substitutes is common, considering the possibility of adding polyamines to these products. It is worth remembering that the use of milk replacers is also common in animal production.

On the other hand, the AB is a public health concern. The problems resulting from the ingestion of high levels of the various AB are well described in the literature, with characterization of the symptoms for the case of toxicity of the different AB.

The main reports refer to intoxication by fish meat consumption, scombrotoxicosis, as a consequence of contamination by high levels of histamine. It is a primary biogenic and heterocyclic diamine, non-volatile and thermostable, originated by the decarboxylation of L-histidine when the conditions of handling and storage of fish are inadequate because they favor the multiplication of the microbiota of fish. Histamine has allergenic potential and can cause intoxication in humans.

For this reason, limitations have been imposed on the presence of histamine in food, as is the case of the United States Department of Agriculture (USDA) in the United States (100 mg/kg) and the European Food Safety Authority (EFSA) in Europe (50 mg/kg). In Brazil, IN °46/2011 of the Ministry of Agriculture, Livestock and Supply (Mapa) establishes a tolerance of 100 ppm of histamine in canned fish.